Effects of Preparation Parameters on Paraffin Wax Microemulsion

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Influence of preparation method on performance of a metal supported perovskite catalyst for comb

J OURNAL OF RARE EARTHS,Vol.28,No.1,Feb.2010,p.54F j y M y f S T y f B j (D 55)LUOG (@)DOI 6S ()65Influence of pr eparation method on performance of a metal suppor ted per ovskite catalyst for combustion of methaneZHAI Yanqing (翟彦青),XIONG Jieming (熊杰明),LI Cuiqing (李翠清),XU Xin (徐新),LUO Guohua (罗国华)(Department of Chemical Engineering,Beijing Institute of Petro-chemical Technology,B eijing 102617,China)Received 21March 2009;revis ed 1June 2009Abstract:A different method was employed for the preparation of a metal supported perovskite catalyst for the catalytic combustion of meth-ane.The prepared metallic catalysts were characterized by means of X-ray diffractometer (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM),and also by ultrasonic and thermal shock tests and catalytic activity.It was found that the process factors during the preparation,e.g.the preparation of the catalyst precursor and the coating slurry,the calcination temperature,all had strong effects on the activity and stability of the coated catalyst.Based on the experimental results,it was proposed that the sample adopted spray-pyrolysis method showed better catalytic activity and adhesion stability than those adopted co-precipitation and sol-gel.The increasing calcinations temperature could enhance adhesion stability,but reduce catalytic activity.For the coated samples,XRD illuminated that the typical well-crystallized perovskite structure was formed on the metallic surface after calcined at 800 C.SEM and TEM micrographs of the samples showed obvious dissimilarity at morphology aspect by different preparation methods.The LaMnO 3catalyst on the support by the spray-pyrolysis method had a mass loss 26%after 30min ultrasonic treatment and 7%after 10times thermal shock.Keywords:methane combustion;metallic monolith;perovskite catalyst;preparation method;adhesion;catalytic activity;rare earthsNatural gas is cleaner fuel than coal and petroleum.How-ever,the temperature of the methane combustion flame is higher than 1300C,and thus leads to a large amount of ther-mal NO x emission and a substantial heat loss [1].The catalytic combustion of the methane is one of the most promising processes to produce environmentally clean energy [2].In view of a practical application,the monolithic struc-tured catalyst is the only possible configuration of the cata-lytic combustion catalyst.The monolith catalyst has a lower gas-dynamic resistance than granulated catalyst.In addition,in monolith catalyst the cross section of heat and mass flows are uniform and decrease the probability of the formation of “hot ”zones and improve the time-on stream behavior of the catalyst and process selectivity [3].Metallic monolith exhibits several advantages over ce-ramic monolith,e.g.,with a better thermal and mechanical shock resistance,a high thermal conductivity,thus delaying catalytic and structural thermal damage.Moreover,it can be made with thinner walls than its ceramic counterpart,thus possessing a higher contact surface area.However,some disadvantages may be attributed to a metallic monolith,such as the non-porous nature of the metal,and the mismatch in the thermal expansion between the support and the coating layer [4].FeCrAl alloy has been used as a support in catalytic combustion due to its outstanding resistance to a high tem-perature,up to 1200C in air.This behavior depends on the diffusion of Al towards the surface and its oxidation into a pro-tecting layer of α-alumina,thus preventing the metals fromfurther oxidation and undesired alloy degradation.The aluminalayer is also quite useful for catalyst layer anchoring purpose [5].Perovskite-type catalyst has attracted great attention for combustion application as alternative to the very active no-ble metal catalyst [6].Development of the perovskite-based structured catalysts appears to be a very promising strategy to cope with all of those applications of catalytic combustion,which does not require extremely high activity at low tem-perature,but can benefit from a more heat-resistant and du-rable catalyst [7].Despite a considerable number of papers dealing with perovskite in the oxidation reactions,a few pa-pers have focused on the preparation of perovskite-based monolithic catalyst using La stabilized γ-Al 2O 3[8],corun-dum [9],zirconia [10]substrates or directly extruding active honeycomb structure system [11].For the metallic support,Cerri and colleagues [12]have investigated the catalytic per-formance of catalytic burner by employing the combination of a FeCrAl alloy fiber and perovskite catalyst.They have developed and optimized the technology of spray-pyrolysis of perovskite catalyst on metal surface.This paper reported the results of a study on FeCrAlloy supported perovskite for catalytic combustion of methane.The influence of the preparation method and calcination temperature on phase composition,micrograph,catalytic ac-tivity and adhesive of catalyst layer was investigated.1Experimentalound at ion ite m:Pro ect supported b the inistr o c ience and echnol og o ei ing 2008100000142Corre sponding a uthor :uohua E-m ail :luoguohua :10.101/1002-072109000-8ZHAI Yanqing et al.,Influence of preparation method on performance of a metal supported perovskite catalyst for combustion (55)1.1Prepar ationThe FeCr alloy(0.1mm thick)was used as the support. The sheet was cleaned ultrasonically in acetone and de-ionized water,and then was calcined at900C for5h. The heating rate was5C/min.1.1.1Co-precipitation A mixed solution of La,Mn nitrates with a total concentration of around1mol/L was employed, and a mixed solution of(NH4)2CO3and NaOH was used as a precipitating agent.The precipitation was carried out at am-bient temperature with pH9–10,followed by aging for3h. The precursor material was filtrated,washed and dried at 120C,and finally was calcined at700C for3h.The obtained powder dispersed with10wt.%ethanol and acetylacetone in a mixed solution of1:1.The suspension was then subjected to ball milling for10h.The pretreated sup-port was dipped into the slurry for3min and withdrawn slowly to ensure uniformity.Afterwards,the material was dried at80C for10min and calcined at800C for1h.The dip-coating and calcination process was repeated three times. Finally,the material was calcined at800,900,and1000C for5h in air,respectively.1.1.2Sol-gel The preparation process was as follows:the mixture of La(NO3)36H2O,Mn(CH3COO)24H2O was mixed with30wt.%citric acid and40wt.%water.The ob-tained solution was slowly heated at80C,until generating little viscous liquid.The pretreated metallic support was immerged in the vis-cous liquid for3min and withdrawn slowly to ensure uni-formity,then dried at120C and calcined at800C for1h. The dip-coating and calcinations process was repeated sev-eral times in order to obtain suitable loading of the catalyst on the support.Finally the material was calcined at800,900, and1000C for5h,respectively.1.1.3Spray-pyrolysis The mixture solution was composed of La(NO3)36H2O and Mn(CH3COO)24H2O with a molar ratio of1:1,30wt.%of citric acid and40wt.%water.The resulting equivalent LaMnO3concentration was0.7mol/L. The pretreated metallic support was heated in an oven up to900C,quick immerged in above solution,taken out af-ter10s,then dried at120C and calcined at800C for1h. The above process was repeated several times.Finally the material was calcined at800,900,1000C for5h,respec-tively.1.2Charact erizationXRD patterns were collected by a Rigaku D/max2500 X-ray diffractometer using the Cu Kαradiation(λ=0.15418nm), tube voltage40kV,tube current100mA.The morphology of samples was observed by a Quanta 400scanning electron microscope(FEI Corporation).The textural features of catalyst powder were studied by TEM with a JEM-100CX II.T f y y yT,treated in an ultrasonic bath for0.5–30min.The mass loss was measured.The thermal shock test was carried out by heating the coated sheets to800C at a heating rate10 C/min,holding for20min at800C,and dropping them immediately into water at25 C.After dried at120C,the mass loss was measured.The process was repeated10times. The catalytic activity was measured with a conventional tubular reactor under atmospheric pressure.The metal sheets coated with catalyst were cut into pieces of0.2–0.3×2–3cm.A bundle of pieces containing around0.3g perovskite were retained in the quartz tube vertically.A gas mixture of1.5 vol.%CH4and98.5vol.%air was used as a feed at a space velocity of60000ml/(g h),calculated according to the mass of the catalyst layer.The composition of the product was analyzed by an on-line Angilent4890gas chromatography with a thermal conductivity detector.2Results and discussion2.1Effect of the support pre-treat mentPretreatment must be conducted on support’s surface,be-cause smooth metallic surface is difficult to adhere catalyst. It has been demonstrated that at temperatures higher than 900C the aluminum diffuses preferentially,compared with the other alloy components,from the bulk of the material to the surface where the compact alumina was formed[5].The advantage associated with the alumina film is its compati-bility with alumina-containing washcoat,which substantially eases application and ensures its adhesion to the support. Furthermore,the Al2O3film protects the core of support free of further oxidation.For above reason,900C is selected as pretreatment temperature for the metallic support.The alloy possesses an obvious metallic luster and a smooth surface before pre-treatment.The metallic luster disappears and its surface becomes coarse after the alloy has been calcined at900C.The XRD pattern demonstrates that α-Al2O3phase forms,as seen in Fig.1(5).Fig.2(a)shows the SEM micrographs of pre-treated support.It can be seen that a coarse and dense oxide layer is well anchored to the metal surface with a tight structure.A lot of alumina whisk-ers completely cover metal surface,which increases greatly the surface area of the metal support.2.2Loading of catalystThe influences of the preparation method and calcination temperature on the loading of catalyst are listed in Table1.It clearly shows that the preparation method intensively affects loading of catalyst.For sample prepared by co-precipitation method,the loading attains around3%after two coatings only,whereas similar loading is attained after five coatings for samples prepared by sol-gel and spray-pyrolysis method.The influence of calcination tem-ff,he adhesion o the catal st la er was measured b an ul-trasonic test and a thermal shock test.he coated sheets were immersed in petroleum ether inside a sealed beaker and then perature on loading is negligible.Compared these three di erent method the loading is the56JOURNAL OF RARE EARTHS,Vol.28,No.1,Feb.2010Table 1Preparation method and the weight gains after coatingand calcination of samplesSamplePreparation methodNumber of coating Calcination temperature/C Mass gain/%1Co-precipitation 2800 3.22Co-precipitation 2900 3.03Co-precipitation 21000 3.14Sol-gel 5800 3.05Sol-gel 5900 3.16Sol-gel 51000 2.97Spray-pyrolysis 5800 3.18Spray-pyrolysis 5900 3.19Spray-pyrolysis510002.9highest for co-precipitation method,whereas coating number is the least.For co-precipitation method,the possible reason is that catalyst with certain perovskite structure adheres to support ’s surface in the form of powder,therefore the sample possesses the highest loading.For the sample prepared by sol-gel and spray-pyrolysis method,the precursor salt ad-heres to support surface firstly,then perovskite structure forms on the support after dryness and calcination processes.A lot of water and gas are removed,therefore a part of mass loses.In addition,a part of products in a foamy and brittle state adhere to the support,the foamy products ought to knock for next coating,so repetitious coating is needed for definite loading of catalyst.2.3XRD of the sampleThe XRD patterns of three catalyst coatings in comparison with that of a metal support and a catalyst precursor are de-picted in Fig.1.It shows that the XRD pattern,relative to the powder,shows the presence of rather well crystallized rhombohedral perovskite phase only after calcined at 700 C.For the coated samples,the typical well-crystallized per-ovskite structure is formed on the metallic surface after cal-cined at 800C in despite of different precursor history [13].In the coated samples,weak peaks of Al 2O 3attributed to sup-port ’s surface are detected.No other products are detectable.2.4SEM and TEM micrographs of sam plesThe SEM micrographs of the sample surface by different preparation methods and calcined at 800C are shown in Fig.2.The three samples exhibit obvious dissimilarity at mor-phology aspect.The sample 1shows that the exiguous cata-lyst powder is so close to one another as to form layer.The powder has homogeneous distribution onto the surface of the sheet,without evident conglomeration of catalyst particles.Sample 4reveals that the catalyst possesses two different morphologies, e.g.powder and crystal block.Exiguous catalyst powder particles are so close to one another as to form compact and even layer on the surface of metal.The irregular and vermiform catalyst crystal blocks occupy the complanate powder catalyst surface and form a secondary layer.Sample 7emerges that bigger crystal block close to the support surface and randomized surface cracks exists in the catalyst layer.From SEM it can be seen that a little catalyst exfoliates for all samples.It is known that the thermal expansion coeffi-cients for the perovskite and metallic support are 12×10–6K –1and 16×10–6K –1,respectively [5].With the temperature increasing,thermal stress between support and catalyst be-comes greater,which introduces cracks of a catalytic layer and falling of a small quantity of the catalysts.From TEM micrograph (Fig.3)obvious different size and shape of particles can be seen.The catalyst comprises of round particles for sample 1,whereas it is hexagonal with different size for samples 4and 7.On the basis of extensive image analysis,the average particle size of the catalyst of sample 1is about 100nm,whereas that of the other two samples is about 200nm.2.5Adhesion of catalyst on the supportThe adhesion of catalyst on the support is the important per-formance for the monolith catalyst,whereas many researchersFig.1XRD patterns of samples(1)Metal support calcined at 900C;(2)Perovskite powder cal-cined at 700C;(3)Sample 1;(4)Sample 4;(5)Sample7F S M f ,()S ;()S ;()S ;()S ig.2E micrographs o support calcined at 900C and samples 14and 7a upport calcined at 900C b ample 1c ample 4d ample 7ZHAI Yanqing et al.,Influence of preparation method on performance of a metal supported perovskite catalyst for combustion …57Fig.3TEM image of powder scraped from coated samples prepared by different method(a)Sample 1;(b)Sample 4;(c)Sample 7neglected it.The adhesion of the catalyst on the support pre-pared by different methods and at calcination temperatures has been investigated with ultrasonic and thermal shock test.Similar methods were used by Zhao et al.[14]and Ismagilov et al.[15]Typical mass loss-time curves for all samples during the ultrasonic test are presented in Fig.4.It can be seen that the mass loss increases as the ultrasonic treating time prolongs.For all samples,the figure of trend line is similar in ultrasonic test.The adhesion decreases gradually for the samples prepared by spray-pyrolysis,sol-gel,and co-precipitation method at the same calcination temperature.For the same preparation method,higher tem-perature is beneficial to improving adhesion.The sample 9has the highest stability.The mass loss data for all samples during the thermal shock test are illustrated in Fig.5.The comparative positions of curves of the samples in Figs.4and 5are more similar.During the two different tests,sample 9possesses the highest stability,with a mass loss 26%after 30min ultrasonic treat-ment and 7%after 10times thermal shock,while sample 1possesses the least stable among the 9samples.It can be found that the preparation method and calcina-tion temperature intensively affect the adhesion of catalyst on the support.The mass-loss is the least for the monolith prepared by spray-pyrolysis,due to the in situ pyrolysis oc-curring on the hot panel surface,in which catalyst crystalli-zation occurs leading to a fairly uniform load of catalyst,rather well anchors to the support.Besides abovereasons,F Wf Fig.5Mass loss-number curves ofthermocycletreating of samplesthe catalyst layer with a great deal of gaps can availably prevent the catalyst from falling off during ultrasonic test,because the catalyst falls off as tiny crystal block form with-out a larger piece of catalyst.For co-precipitation method,the catalyst composes integrate coating layer without crack,the catalyst breaks off with a large piece when the sample takes a beating,so mass loss is the most.2.6Catalyt ic activityThe activities for methane combustion reaction of all sam-ples are illustrated in Fig.6.The preparation method and calcinations temperature of samples have obvious effect on the activity.At the same calcination temperature,the cata-lytic activity of the sample prepared by spray-pyrolysis method is the highest with the light-off temperature (denoted 10%conversion)close to 500C,whereas the sample using sol-gel method presents the lowest catalytic activity,with light-off temperature approaching 600 C.The crystalline phase of the sample prepared by spray-pyrolysis method is formed completely,which is in favor of combustion of methane.The activity sequence does not show any relevance to the loading of the active layer.For a specific preparation method,catalytic activity obviously decreases with the in-crease of calcination temperature.3y ,y y ,ig.4eigh t lo ss-time curves du ring u ltrason ic treatment o samplesConclusionsAn active and stable methane combustion composite cata-l st based on a perovskite used as the catal tic la er and a58JOURNAL OF RARE EARTHS,Vol.28,No.1,Feb.2010Fig.6Catalytic activity of samplesFeCr alloy,used as the support was designed.The influence of the three different preparation techniques on the perform-ance of sample was studied.(1)FeCr alloy calcined at900C formed compact and coarse alumina layer,which was benignant for adhesion. (2)All the three technologies(spray-pyrolysis,co-pre-cipitation and sol-gel)were capable of making metallic monolith,which based deposition of LaMnO3catalyst on the support.(3)The preparation method had obvious effect on the ex-terior micrograph,adhesion,and catalytic activity of mono-lith.As a whole,the spray-pyrolysis technology was a prom-ising method for preparing metallic monolith.A higher tem-perature was propitious to increase adhesion,but decreased catalytic activity of monolith.References:[1]Thevenin P O,Menon P G,J r s S G.Catalytic processes toconvert methane:Partial or total oxidation,Part II Catalytic to-tal oxidation of methane.Cattech,2003,7:10.[2]Choudhary T V,Banerjee S,Choudhary V R.Catalysts forcombustion of methane and lower alkanes.A ppl.Catal.,A, 2002,234:1.[3]Norton D G,W etzel E D,Vlachos D G.Fabrication of sin-gle-channel catalytic microburners:effect of confinement on the oxidation of hydrogen/air mixtures.Ind.Eng.Chem.Res., 2004,43:4833.[4]Ferrandon M,Berg M,Bjornbom E.Thermal stability ofmetal-supported catalysts for reduction of cold-start emission in a wood-fired domestic boiler.Catal.T oday,1999,53:647.[5]Badini C,Laurella F.Oxidation of FeCrAl alloy:influence oftemperature and atmosphere on scale growth rate and mecha-nism.Surf.Coat.T echnol.,2001,135:291.[6]Barbero B P,Gamboa J A,Cadu s L E.Synthesis and charac-terization of La1–x Ca x FeO3perovskite-type oxide catalysts for total oxidation of volatile organic compounds.A ppl.Catal.,B, 2006,65:21.[7]Zhao Xin,Yang Qiuhua,Cui Jinjin.XPS study of surface ab-sorbed oxygen of ABO3mixed oxides.Journal ofRare Earths, 2008,26:511.[8]Cimino S,Lisi L,Pirone R,Russo G,Turco M.Methane com-bustion on perovskites-based structured catalysts.Catal.T oday, 2000,59:19.[9]Lyubov A Isupova,Galina M Alikina,Sergei V Tsybulya,Alek-sei N Salanov,Nataliya N Boldyreva,Elena S Rusina,IzabellaA Ovsyannikova,Vladimir A Rogov,Rimma V Bunina,Vladislav A Sadykov.Honeycomb-supported perovskite cata-lysts for high-temperature processes.Catal.T oday,2002,75: 305.[10]Cimino S,Pirone R,Lisi L.Zirconia supported LaMnO3mono-liths for the catalytic combustion of methane.A ppl.Catal.,B, 2002,35:243.[11]Fabbrini L,Rossetti I,Forni L.Effect of primer on honey-comb-supported La0.9Ce0.1CoO3±δperovskite for methane catalytic flameless combustion.A ppl.Catal.,B,2003,44:107.[12]Cerri I,Saracco G,SpecchiaV,Trimis D.Improved-performanceknitted fibre mats as supports for pre-mixed natural gas cata-lytic combustion.Chem.Eng.J.,2001,82:73.[13]Steenwinkel Y Z,Beckers J,Bliek A.Surface properties andcatalytic performance in CO oxidation of cerium substituted lanthanum-manganese oxides.A ppl.Catal.,A,2002,235:79.[14]Zhao S,Zhang J,Weng D,W u X.A method to form well-ad-heredγ-Al2O3layers on FeCrAl metallic supports.Surf.Coat.T echnol.,2003,167:97.[15]Ismagilov Z R,Pushkarev V V,Yu O.Podyacheva N A.Kory-abkina,V eringa H.A catalytic heat-exchanging tubular reactor for combining of high temperature exothermic and endother-mic reactions.Chem.Eng.J.,2001,82:355.。

CFS_预处理对不同秸秆原料酶解和理化结构的影响

山西农业科学 2023，51（12）：1426-1434Journal of Shanxi Agricultural SciencesCFS 预处理对不同秸秆原料酶解和理化结构的影响田鑫，王雨萌，徐师苗，汪强杰，胡轲，张海波，程红艳（山西农业大学资源环境学院，山西太谷 030801）摘要：高铁酸钾复合液（CFS ）是制备高铁酸钾的剩余滤液，其含有大量碱（OH -）和氧化剂（ClO -和Fe 6+），具有破坏木质纤维素顽固结构、提升酶解效率的潜力。

为实现秸秆的资源化利用与高铁酸钾制备废液的再利用，以山西储量丰富的玉米秸秆（CS ）、高粱秸秆（SS ）和谷子秸秆（MS ）为原料，采用CFS 进行预处理，对比3种秸秆的酶解糖化率，分析秸秆的理化结构变化。

结果表明，CFS 预处理中碱和氧化剂共同参与了3种秸秆的降解，促进了酶解糖化率；在最佳预处理时间24 h 下，CS 、SS 和MS 的还原糖产量分别较对照提高252.77%、236.39%、216.66%，其中CS 的酶解效率最高；组分分析表明，CFS 处理能有效去除3种秸秆中木质素成分，增加纤维素相对含量，进而有利于纤维素酶的可及性；结构分析显示，CFS 处理后，3种秸秆的理化结构发生了不同程度变化，粗糙度增加，官能团发生断裂，纤维结晶度升高，热稳定性变差。

在3种秸秆中，CS 结构变化最明显，更有利于被生物转化。

综上，CFS 预处理可改变作物秸秆的理化结构，破坏其致密结构，促进后续酶解效率，是一种理想的预处理技术。

关键词：高铁酸钾复合液（CFS ）；预处理；作物秸秆；还原糖产量；理化结构中图分类号：S141.4 文献标识码：A 文章编号：1002‒2481（2023）12‒1426‒09Effects of CFS Pretreatment on Enzymatic Hydrolysis and PhysicochemicalStructure of Different Straw MaterialsTIAN Xin ，WANG Yumeng ，XU Shimiao ，WANG Qiangjie ，HU Ke ，ZHANG Haibo ，CHENG Hongyan（College of Resources and Environment ，Shanxi Agricultural University ，Taigu 030801，China ）Abstract ： Composite ferrate solution(CFS) is the residual filtrate for preparing potassium ferrate. It contains a lot of alkali (OH -) and oxidant(ClO - and Fe 6+), which has the potential to destroy the recalcitrant structure of lignocellulose and improve the efficiency of enzymatic hydrolysis. In order to realize the utilization of straw resources and reuse of preparation waste liquid of potassium ferrate, in this paper, corn straw(CS), sorghum straw(SS), and millet straw(MS), which are abundant in Shanxi province, were pretreated with CFS, the enzymolysis and saccharification rates of the three kinds of straw were compared, and the change of physicochemical structure of the straw was analyzed. The results showed that the alkali and oxidant in the pretreatment of CFS were involved in the degradation of three kinds of straw, which promoted the enzymatic hydrolysis rate and saccharification rate. Under the optimal pretreatment time of 24 h, the reducing sugar yield of CS, SS, and MS was increased by 252.77%, 236.39%, and 216.66% compared with that of the control, respectively, and the enzymatic hydrolysis efficiency of CS was the highest. Component analysis showed that CFS treatment could effectively remove lignin in three kinds of straw and increase the relative content of cellulose, which was beneficial to the accessibility of cellulase. Structural analysis showed that after CFS treatment, the physicochemical structure of the three kinds of straw changed in different degrees, roughness increased, functional group fractured, fiber crystallinity increased, and thermal stability decreased. Among the three kinds of straw, CS had the most obvious structural change and was more conducive to biotransformation. In conclusion, CFS pretreatment could change the physicochemical structure of crop straws, destroy the dense structure and promote the efficiency of subsequent enzymatic hydrolysis, so it was an ideal pretreatment technology.Key words ：composite ferrate solution(CFS); pretreatment; crop straw; reducing sugar yield; physicochemical structuredoidoi:10.3969/j.issn.1002-2481.2023.12.11收稿日期：2023-01-04基金项目：山西省高等学校科技创新项目（2020L0137）；山西农业大学科技创新基金项目（2018YJ39）；山西省优秀博士来晋工作奖励基金（SXYBKY201803）；国家自然科学基金（52100149）；山西省水利科学技术研究与推广项目（2022GM034）作者简介：田　鑫（1997-），女，山西汾阳人，在读硕士，研究方向：农业环境保护与废弃物资源化利用。

Presentation -08102014 (1)

1st of May - Middle of May Methodology
Baixi Zhu
36%
101 relavent academic articles 1950 - 2014 36% of the literatures after 2002
Problem Statement
Based on The Literature Review GapFill in The TheIndustry Gap
Certain Drilling Method
Diamond Analysis of Different Factors or Percussive or Rotary Rotary Different Statistics and Mathematical Method or Percussive
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ANN results
Drilling method Sample points R value MSE Rotary 198 Diamond Percussive 60 56
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Introduction
The Importance of Drillability Model:
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Consider Common Parameters

两性离子-阴离子双交联P（AAm-co-AAc-co-SBMA-co-AMPS）

第 4 期第 183-191 页材料工程Vol.52Apr. 2024Journal of Materials EngineeringNo.4pp.183-191第 52 卷2024 年 4 月两性离子-阴离子双交联P（AAm-co-AAc-co-SBMA-co-AMPS）/Fe3+水凝胶的摩擦学性能研究Tribological properties of zwitterionic-anionicdual-crosslinked P（AAm-co-AAc-co-SBMA-co-AMPS）/Fe3+ hydrogel李子恒1，王斌斌1，尤德强1，李卫1，王小健1，2*（1 暨南大学先进耐磨蚀及功能材料研究院，广州 510632；2 暨南大学韶关研究院，广东韶关 512029）LI　Ziheng1，WANG　Binbin1，YOU　Deqiang1，LI　Wei1，WANG　Xiaojian1，2*（1 Advanced Wear & Corrosion Resistant and Functional Materials，Jinan University，Guangzhou 510632，China；2 Shaoguan ResearchInstitute of Jinan University，Shaoguan 512029，Guangdong，China）摘要：水凝胶是一种理想的软骨修复材料，但目前很难有人工材料能实现软骨的超低摩擦因数。

使用两性离子单体［2-（甲基丙烯酰氧基）乙基］二甲基-（3-磺丙基）（SBMA）和阴离子单体2-丙烯酰氨基-2-甲基丙磺酸（AMPS）合成一种两性离子-阴离子双交联P（AAm-co-AAc-co-SBMA-co-AMPS）/Fe3+水凝胶。

在水和PBS中进行摩擦学测试，以评估两性离子和阴离子基团对摩擦因数（CoF）的影响。

结果表明：SBMA和AMPS引入的物理交联点可以提高水凝胶的抗压强度，在水中实现了较低CoF（0.04）；此外，在PBS中观察到CoF进一步降低至0.015，CoF的降低是由于水凝胶在PBS中浸泡产生的高度水合上层所造成的。

氢氧化镍材料制备的研究进展

氢氧化镍材料制备的研究进展吕祥;和晓才;俞小花;谢刚【摘要】The preparation methods of nickel hydroxide [Ni (OH)2],such as liquid phase precipitation,homogeneousprecipitation,hydrothermal,oxidation,high pressure hydrolysis,ion exchange resin,microemulsion,electrolysis and mechanochemical synthesis were described.The effects of preparation process on thestructure,morphology,size and capacity of products were discussed.The preparation method of doped Ni (OH)2 was reviewed and the influence of the added elements on the structure,capacity and electrochemical performance of Ni(OH) 2 was analyzed.The influence of pH and CO32-on the size and morphology of Ni (OH)2 particles during the hydroxide was discussed,preparation of modified nickel was discussed.The application foreground of nano-size Ni(OH) 2 and doped Ni(OH) 2 was prospected.%对氢氧化镍[Ni(OH)2]的制备方法,如液相沉淀法、均相沉淀法、水热法、氧化法、高压水解法、离子交换树脂法、微乳液法、电解法和机械化学合成法等进行叙述;阐述制备工艺对产物结构、形貌、尺寸和容量等方面的影响.进一步综述掺杂Ni(OH)2制备工艺方法并分析添加元素对Ni(OH)2结构、容量、电化学性能的影响;讨论制备改性Ni(OH)2过程中pH值、CO32-对Ni(OH)2颗粒尺寸与形貌的影响.展望纳米Ni(OH)2和掺杂Ni(OH)2的应用前景.【期刊名称】《电池》【年(卷),期】2017(047)001【总页数】4页(P56-59)【关键词】氢氧化镍[Ni(OH)2];掺杂;纳米材料;电化学性能;尺寸;形貌【作者】吕祥;和晓才;俞小花;谢刚【作者单位】昆明理工大学冶金与能源工程学院,云南昆明650093;昆明冶金研究院,云南昆明650031;昆明理工大学冶金与能源工程学院,云南昆明650093;昆明理工大学冶金与能源工程学院,云南昆明650093;昆明冶金研究院,云南昆明650031【正文语种】中文【中图分类】TM912.2为开发比容量高、温度范围广、可大电流放电、成本低、无污染的镍基电池，需要不断加深对正极材料氢氧化镍[Ni(OH)2]性质的了解。

费-托合成中的水煤气变换反应

费-托合成中的水煤气变换反应蔡丽萍沈菊李唐浩东刘化章* 杨霞珍(浙江工业大学工业催化研究所杭州 310014)摘要评述了近年来有关费-托合成中的水煤气变换反应的研究进展，着重介绍了费-托反应条件下发生的水煤气变换反应的热力学分析、反应机理和动力学。

同时介绍了催化剂制备、操作参数等因素对水煤气变换反应的影响。

关键词水煤气变换反应费-托合成机理动力学The Water Gas Shift Reaction in Fischer-Tropsch SynthesisCai Liping, Shen Juli, Tang Haodong, Liu Huazhang *, Yang Xiazhen(Catalysis Institute of Zhejiang University of Technology, Hangzhou 310014)Abstract In this paper, the development of research on the water gas shift(WGS) reaction in theFischer-Tropsch synthesis (FTS) was reviewed. The WGS reaction is important when synthesis gas with nonstoichiometric amounts of hydrogen is used, whereas CO efficiency is decreased accordingly. Its thermodynamic analysis, reaction mechanism and kinetics in conjunction with the FTS are presented. The WGS reaction is equilibrium or close to equilibrium reaction under Fischer-Tropsch conditions on catalysts with a high water gas shift activity such as iron-based FTS catalysts, which may operate via a mechanism with a formate species or via a direct oxidation mechanism. The kinetic studies assumed that the WGS reaction proceeds on a different catalytic site than the FTS. The effects of catalyst preparation and operation parameters on the WGS reaction activity are also summarized. The importance and prospect of research on the WGS reaction under the Fischer-Tropsch conditions are proposed.Key words Water gas shift reaction(WGS reaction), Fischer-Tropsch synthesis(FTS), Mechanism,Kinetics21世纪，世界能源的需求量仍将继续增长，费-托合成(Fischer-Tropsch synthesis ，简称为FTS)作为一个清洁利用煤炭和天然气资源的途径，受到各国能源部门的重视。

脱细胞脂肪组织制备：能否成为异体注射或原位成脂的软组织填充物

《中国组织工程研究》 Chinese Journal of Tissue Engineering Research
脱细胞脂肪组织制备：能否成为异体注射或原位成脂的软组织填充物 ·综述·
聂佳莹，易阳艳，朱元正(南昌大学第二附属医院整形美容科，江西省南昌市 330006)
DOI:10.3969/j.issn.2095-4344.2213
摘要背景：通过脱细胞脂肪组织构建无种子细胞的组织工程脂肪为当前软组织填充的研究热点。目的：探讨近年来脱细胞脂肪组织的制备方法对其移植后诱导脂肪再生效果的影响，并展望其临床应用前景。方法：检索 1971 年 1 月至 2018 年 12 月 PubMed 数据、Elsevier 数据库相关文献，英文检索词为“adipose tissue engineering；adipose tissue extracellular matrix；soft tissue repair；angiogenesis；adipogenic induction”。阅读近年国内外与脱细胞脂肪组织制备和移植相关的文献，从脱细胞脂肪组织制备方法的改良，交联细胞因子和生物材料等方面进行总结归纳。结果与结论：当前研究表明，脂肪组织细胞外基质可作为软组织填充的理想支架材料，植入皮下可募集宿主干细胞并诱导期增殖和成脂分化。但现有的脱细胞方案会导致细胞外基质蛋白和结构的损失，这极大的影响了脱细胞脂肪组织植入体内的脂肪再生能力，但通过超临界二氧化碳设备脱油、机械力预处理、交联细胞因子或生物材料等手段可以减少脱细胞脂肪组织制备过程中细胞外基质蛋白的损失和或补充具有促进组织再生功能的蛋白，最终提高脱细胞脂肪组织移植后的血管和脂肪新生能力。脱细胞脂肪组织由于其天然的成脂诱导能力，在脂肪组织工程中具有强大的应用前景，若能克服其制备流程中细胞外基质蛋白损耗或在安全可控的前提下，有望成为可异体注射并原位成脂的理想软组织填充物。关键词：脂肪组织工程；脂肪组织细胞外基质；软组织修复；血管新生；成脂诱导中图分类号：R446；R496；R318 基金资助：国家自然科学基金资助项目(81660326)，项目负责人：易阳艳；江西省自然科学基金资助项目(20171ACB20037)，项目负责人：易阳艳

pid参数整定方法（PIDparametertuningmethod）

pid参数整定方法（PID parameter tuning method）PID parameter tuning methodIn view of the combined device instrument loop control rate is relatively low, most of the circuit is operated manually, which not only increases the operator's workload, but also have a certain impact on the quality of the products, especially the preparation of a PID parameter tuning method.First, modify the PID parameter must have "SUPPERVISOR" and above permissions, permissions with the keyboard keyHandover permission, the key has been sent to a joint director Chen Sheng hands;Two, open the modified control loop detail screen, turn to the page shown below, modify the PID control backThe three parameters of the path setting are K, T1, T2;Three, the meaning of the PID parameter representsK: proportional gain (amplification), ranging from 0 to 240;T1: integral time, the range is 0 to 1440, the unit is minutes, and the 0 represents no integral action;T2: differential time, the range is 0 to 1440, the unit is minutes, and the 0 represents no differential action.Four, the role of PID parameters(1) the characteristics of proportional adjustment: 1, the adjustment function is quick, the system appears a deviation, the regulator immediately amplifies the deviation K times; and 2, the system has residual.The smaller the K transition process is more stable, but more than the larger difference; the increase of K, residual error will be reduced, but can not completely eliminate the residual error, can only play the role of coarse, but K is too large, the transition process is easy oscillation, K is too large, there may be divergence oscillation.(2) the characteristics of integral regulation: regulation and output change integral input deviation is proportional to the integral and integral function can eliminate the residual error, but reduces the stability of the system, T1 changes from big to small, integral effect from weak to strong, eliminate the residual capacity only from weak to strong, the elimination of bias, the output will stop change.(3) the characteristics of the differential regulation of the output differential regulation is regulated variable rate is proportional to, can improve the quality control in the introduction of differential effect, but the differential effect is too strong, will sometimes open and closed by the control valve, so T2 can not take too much, when T2 increases. Differential effects of capacity lag from weak to strong, has obvious effect, but the effect of no delay.Five. If you want to know how the control loop works, you canenter the detailed picture of the control loop and enter the page shown below:Among them, "CTLACTN" represents the mode of action of the controller, and "REVERSE" means reaction, and "DIRECT" represents the positive function.Six 、 controller selection method(1) the choice of P controller: it is suitable for controlling the system with smaller channel delay, little load change, and allowing the controlled quantity to vary within a certain range;(2) the selection of PI controller: it is suitable for the control system with less delay and little load change, and the controlled quantity is not allowed to be surplus;(3) the choice of PID controller: it is suitable for the control system, such as temperature control system, which has large load change, large capacity delay and high quality control requirements.Seven, PID parameter tuning methodIn engineering applications, empirical test method is adopted.The empirical method is most practical in practice. In setting parameters, the system response must be carefully observed, and the parameters are adjusted according to the response of the system. To observe the response of the system, you can look atthe real-time trend curve in the control loop detail screen, and the decay curve is preferably 4:1, that is, the ratio between the previous peak and the latter peak is 4:1.Experience value: in actual debugging, you can only set an experience value roughly, and then modify it according to the adjustment effect. The P here represents the degree of proportionality, P = 1/K.Parameter rangeControl systemP (1 / K)KT1 / MinT2 / Minlevel20% to 80%1.25 to 5--pressure30% to 70%1.43 to 3.40.4 to 3-flow40% to 100%1 to 2.50.1 to 1-temperature20% to 60%1.7 to 5From 3 to 100.3 to 1In short, in the whole time can not let the system appeardivergent oscillation, such as divergence oscillation, should be immediately cut for the manual, etc. system stability decreases after amplification, increase or decrease the differential integral time time again to switch to automatic control.The smaller the amplification is, the more stable the transition process is, but the larger the residual error is. The larger the amplification is, the easier the oscillation occurs during the transition. The smaller the integration time, the faster the elimination of the residual difference, but the system oscillation will be larger, and the larger the integration time, the slower the system will eliminate the residual error. The differential time is too large, the system oscillation frequency increases, the regulation time increases, the differential is too small, the system regulation is slow.Steps of the method of controller parameter testing:Because the ratio is controlled, so the basic proportion, trying to be good, the transition process has been basically stable, and then add the integral eliminateresidual error finally joined the differential role to further improve the quality control, the basic steps are as follows:(A) for the P controller, the magnification is placed in a smaller position, and the K is gradually increased. The transition process curve of the controlled quantity is observed until the curve is satisfied;(B) the PI controller, the first set of T1=0, according to theproportion of the role of pure tuning amplification to achieve 4:1 attenuation curve; then K reduced (10 ~ 20%), the integral time T1 from large to small gradually added, until the decay process of 4:1;(C) of PID controller, T2 = 0; according to the PI effect of trying setting procedures K, T1 parameters, and then the magnification increases to more than the original large (10 ~ 20%), after T1 also reduced properly to T2 increases gradually, observe the transition curve, until a satisfactory. Through the process of.In a word: when setting parameters, we should carefully observe the system output and the amount of change, and then modify the PID parameters according to the specific conditions. It can be said that as long as process technicians spend more time, most control systems adopt PID regulation to meet the requirements.Eight 、 series pole control loop settingThe setting of the cascade control circuit can be accomplished by two steps, that is, setting the secondary circuit first, then setting the main loop, or adopting a one step method, that is, setting the main and auxiliary circuits simultaneously.(1) when the experience value of the secondary circuit is used as the following value, the general auxiliary circuit only uses proportional control:Secondary variableMagnification factor (K)Degree of proportionality (P)temperature5 to 1.720% to 60%pressure3 to 1.430% to 70%flow2.5 to 1.2540% to 80%level5 to 1.2520% to 80%(2) cascade control loop system is put into operation, and then the parameters of the main controller are adjusted according to the single loop control system parameter tuning method;(3) if there is "resonance" in the tuning process, only the main and auxiliary controller decreases the magnification can be eliminated, if the resonance is too intense, the first switch to manual production, to be stable after re operation, re setting.In conclusion, P is the most basic control function. After adding I, it can control the difference and improve the control accuracy. Adding D can improve the quality of control.Nine, matters needing attention(1) the parameter tuning before calibration of sensors and actuators, ensure the instrument is normal, you can just getDynamic control test, manual state measurement parameters should be stable and reliable.(2) setting the K parameter according to the experience value, turning off the integral adjustment temporarily, and switching to the automatic observation step response,It should be noted that the output of the controller, to determine what is not the negative feedback circuit (wiring design and check whether there are loopholes, when new system debugging will encounter this kind of situation, such as: the need to close the opening of the regulator, it is to enlarge the degree);(3) to ensure the stability of the process when settingparameters, it should be cut immediately when the product quality and process parameters are affectedManual control,When the process is stable, the PID parameter is automatically modified.(4) if it is a cascade and proportional control loop, we must first make a loop, a loop setting, we should also pay attention to the firstThe principle of inner ring, outer back and outer ring.(5) when manually cut to the automatic, make sure that the given value is approximately consistent with the measured value, but for a combinationHoneywell DCS does not have this problem; when manually, the given value automatically tracks the measurements.Ten 、 PID parameter setting shorthandTo find the optimal parameter setting, check the order from small to greatFirst proportion, then integral, and finally add differential additionThe oscillation curve is very frequent, put a small magnificationFloating around the curve magnification to a WAN,The curve deviates slowly and the integration time drops The curve fluctuates long and the integral time is longer The curve oscillates with a frequency that falls off first Moment to slow wave, differential time should be lengthenedThe ideal curve has two waves, the front high and the rear 1, and the lower 4A look at two tones, more analysis, the quality of regulation will not be lowEleven typical control loop1 、 single loop control:(1) control valve action mode selection principle:Control valve in accordance with the role of gas distribution, gas off two. The air opening valve is opened with the increase of the signal pressure, and has no letterNo. when the valve in the fully closed state; on the other hand, with the increase of signal pressure, the valve gradually closed, no signal when the valve is fully open state for gas off valve.The selection principle is mainly from the safety of production, from the guarantee of product quality, from the loss of raw materials and power, from the characteristics of the media to consider these aspects.(2) selection of controller action mode:Selection principle: make the whole single loop constitute negative feedback system.Regulations：Control valve: gas open for "+", "gas off" type -";Controller: the positive action is "+", and the reaction is "" -";Object: when the material or energy increases through the control valve, according to the process mechanism analysis, if the controlled quantity increases with "+", then decreases to "-"";Transmitter: generally considered as a positive link.Then the positive and negative selection discriminant of the controller is:(the controller is "+") (the control valve "+") (object "+") = "-"2 、 cascade loop control:In the single loop control system, it has been pointed out that the principle of selecting the positive and negative modes of the controller is to make the whole control system constitute a negative feedback system, and the discriminant of "product is negative" is given. This criterion is also applicable to the choice of the positive and negative modes of the primary and secondary controllers in the cascade control system.(1) main controller action mode selection:(main controller +) (sub object +) (main object =) = (-)So when the main and auxiliary variables change in the same direction, the main controller should be counterproductive, reversal is the role of Party A.Type.(2) acting mode selection of auxiliary controller:(auxiliary controller +) (control valve +) (secondary object =) = (-)(3) cascade control loop is put into operation:The operation of the utility model is to transfer the master and the auxiliary controllers from the manual operation state to the working state through proper stepsState. Operation method of cascade control system, there are two kinds: one is the first deputy after the main ring ring; the other is the first investment after the main ring ring. Operation method is widely used for the first time, put into operation to ensure the switch without disturbance, because the Honeywell DCS with PV automatic tracking function so basically can switch without disturbance, and the operation is relatively simple.3, split control systemThe split control system is the output signal of a controller to control two or more control valves, each of themThe control valve works only within a signal of the entire range of the output signal.That is, multi valve and sub pass.The implementation method mainly uses two kinds: one is through each control valve positioner, two is through the DCS software realization, in the use of DCS control, we usually through the DCS configuration implementation.In process control system, in accordance with the control valve of the gas switch action and gas can be divided into two categories: one is the same as the action to the valve, the control valve input signal increases or decreases, the valve open or open, the other is different to the valve action, as control valve input signal increases or decreases, the valve is always according to a valve closed and another valve openingdirection of action. The choice of the same or opposite direction of the control valve is determined by the need of the process. As detailed below:4, ratio control loopA ratio control circuit is a system that automatically maintains a certain proportion of two or more of the two materialsThe amount of material from the raw material with the amount of change according to a certain ratio, such as gas waste heat boiler and air intake volume is proportional to the combustion of the boiler to achieve the best effect.。

生物质能源课程结业论文

生物质能源课程结业论文SHENGWUZHINENGYUAN KECHENGJIEYELUNWEN学院：西南林业大学材料工程学院专业：生物质能源与材料工程姓名：卢宇晗学号：20151113015教师：郑志锋静电纺丝法制备木质素基碳纤维卢宇晗摘要：碳纤维材料是一种性能优异的、相对较新的多功能型材料，现在市场上最多的碳纤维材料多是以石油基或是沥青基为前体的，但随着石油能源危机与环境保护意识的日益崛起，碳纤维材料不得不寻找新的前体来保证它的供应。

木质素，一种天然的可再生的有机材料出现在人们的视野。

木质素基碳纤维的出现，不仅解决了能源短缺的问题，同时也符合可持续性地绿色发展的社会需求。

目前对于碳纤维的制备方法以熔融纺丝为主，干法纺丝等为辅，但缺少对于静电纺丝方法制备碳纤维的系统性研究，所以本文除了对木质素基碳纤维的概述外，还对静电纺丝方法制备碳纤维做一个总体的了解。

关键字：木质素基碳纤维，静电纺丝法Preparation of lignin based carbon fibers by electrospinningYuhan LuAbstract: Carbon fiber material is a kind of superior performance and new type of multifunctional material，at present，most of the carbon fiber materials in the market are based on petroleum base or asphalt base，but with the rising of oil energy crisis and environmental protection consciousness，carbon fiber material has to look for new precursors to ensure its supply . Lignin, a natural and renewable organic material that appears in people's field of vision . The emergence of lignin based carbon fiber, not only solve the problem of energy shortage, but also in line with the social needs of sustainable green development . At present，the preparation method of carbon fiber is mainly based on melt spinning，dry spinning，and so on . But the study on Preparation of carbon fibers by electrospinning method was very seldom . So this paper not only on an overview of the lignin based carbon fibers，but a general understanding of the electrospinning method preparing carbon fiber.Key words: Lignin, Carbon fiber, Lignin based carbon fiber, electrospinning引言碳纤维（Carbon Fibre）是一种含碳量在95%以上的、具有高拉伸强度和拉伸模量的、相对较新的轻质材料，由于其产品的高端性，最初只在航空航天工业上使用[1]。

Effects of processing parameters on the mechanical properties

Material PropertiesEffects of processing parameters on the mechanical propertiesof polypropylene random copolymerSenol Sahin,Pasa Yayla*Mechanical Engineering Department,Engineering Faculty,Kocaeli University,41040Kocaeli,TurkeyReceived9June2005;accepted19July2005AbstractThe mechanical properties of polypropylene random copolymer(PP-R)with different processing parameters were studied. Special attention is devoted to the investigation of the inﬂuence of masterbatch addition on the variation in the mechanical properties of injection moulded PP-R.Tensile,instrumented Charpy impact,Shore D hardness,differential scanning calorimeter(DSC)and Vicat softening temperature(VST)tests were conducted on the test samples containing different colour masterbatches varying from0.5to10wt%.The observed changes in the mechanical behaviour are explained by the type and level of masterbatch content.The natural UV weathering performance of the PP-R material was studied from the masterbatch type point of view.The effect of processing parameters on material performance was studied on samples which were directly obtained from extruded pipes and on injection moulded samples.Finally,the effects of storage time on the polymer properties were investigated.q2005Elsevier Ltd.All rights reserved.Keywords:Polypropylene random copolymer;Processing parameters;Masterbatch types;Masterbatch contents;Ultraviolet degradation; Storage time1.IntroductionThe use of plastic materials in pipe applications is well established because of the lightweight,high performance, and excellent corrosion performance they can offer compared with metallic materials such as iron and copper. Having achieved high level of penetration in different applications,varying from water supply to gas distribution networks,from sanitary and heating systems to waste water collection and discharge systems,the use of plastics is expected to continue growing steadily at a rate of about5–10%per year[1].In many applications it is necessary to pigment the resin to speciﬁc colour for modifying the optical appearance for design,styling and functional purposes.Because of the importance of pigment addition to the base polymer,many studies[2,3]have been undertaken to understand their effects on the performance of plastics,especially since it has been shown that incorporating additives into polymeric materials during fabrication often affects rheological[4], mechanical[5,6]and optical properties[7]in an unpredict-able,and sometimes detrimental manner.PP can be coloured by two different methods.In theﬁrst method, certain types of colouring pigments are added to the natural base polymer at a certain pre-deﬁned percent by the converters during either injection moulding or extrusion of theﬁnal product.In the second method,the base polymer is coloured by the raw material producer by compounding during the production process.Since the second method gives more uniform colouring,both the raw material producers and,generally,the end-users prefer compounded polymer.The polymer producers claim thatthe *Corresponding author.Tel.:C902623351148;fax:C902623352812.E-mail address:pyayla@.tr(P.Yayla).development of coloured PP-R raw material has to be done by the polymer producers due to the fact that speciﬁcally designed compounding equipment is used to obtain proper pigment and additive distribution without damaging the molecular structure[8].Furthermore,it is generally claimed that coloration with masterbatches done by the converters leads in general to poor pigment dispersion,resulting in pigment agglomerates acting as defects in the polymer matrix and impairing the mechanical properties of the ﬁnished product.In fact,when a colour masterbatch is used during the converting,the distribution level achieved in the extruder is usually not acceptable,resulting in uneven distribution[8].Despite these disadvantages,colouring by the polymer converter is cheaper and gives them some additional logistic advantages.Moreover,it is fairly seldom that a speciﬁc colorant is added to the reactants during a polymerisation process,unless such polymer resin is required in a large volume.Polypropylene random copolymer(PP-R)is one of the fastest growing of plastics being used in sanitary and heating applications.The overall mechanical properties of PP are strongly inﬂuenced by testing and processing parameters of the polymer.Hence,knowledge of relations between structure and mechanical properties of polymers enables the manufacturers to produce materials with certain morphologies by altering the processing conditions[9]. The inﬂuence of testing parameters on the overall performance was discussed in Part1of this work[10]. Determining the effects of processing parameters on the mechanical properties of PP-R is the objective of this study. Special attention is devoted to the investigation of inﬂuence of masterbatch addition on the variation in the mechanical properties.2.Experiments2.1.MaterialsThe base polymer used in this study is a natural colour polypropylene random copolymer(PP-R),produced by Borealis S.A.,trade name Borealis RA130 E.The properties of this natural PP-R are given in the work by Sahin and Yayla[10].It is known that colouring in general and the method of colouring in particular,might have some inﬂuence on the mechanical properties of the polymer[11].In this study,the effect of colouring methods on the overall mechanical performance of PP-R is investigated.In addition to the method of colouring,the types of pigment used for colouring could inﬂuence the overall mechanical performance of the material.In general,inorganic pigments yield more stable and better mechanical properties than organic anic pigments, however,are known for their high colour strength, brightness and good transparency[12].In order to determine the effects of different colouring on material properties,four different colour masterbatches were used.The masterbatches used to make theﬁnal product in different colours were supplied by local masterbatch manufacturers.They were supplied in granule form and the carrier resin for pigments for the all types of masterbatches was PP-R.The typical properties of masterbatches used in this study are detailed in Table1.Four different coloured PP-R materials,compounded during polymerisation by the above named producer,were used to prepare test samples.From the producers’point of view,there is no signiﬁcant difference in the typical properties of these different colour compounds.2.2.Specimen preparationFour different groups of samples were prepared in this investigation.For theﬁrst group,an un-compounded natural material was coloured during the injection process. For this group of samples,different types of masterbatches at pre-deﬁned ratios,varied between0.5,1,2.5,5and 10%in weight,were added during the injection process of the test samples.Before introducing the resin and masterbatches into the injection moulding machine,the masterbatch and the resin were put in a mixer and mixed for about30min.For the second group,a compounded PP-R material in blue,white,grey and green was used to prepare test samples by injection moulding.For these two groups,the detailed information on the injection mould and injection parameters was given elsewhere[10].For the third and fourth groups,the test samples were directly cut and extracted from the extruded pipe manufactured from white colour compounded,and1%white colour masterbatch added materials,respectively.These third andTable1Typical properties of masterbatches used in this studyM1M2M3M4 Colour White Green Blue Black Pigment type Organic Organic/Inorganic Organic/Inorganic Inorganic Total pigment concentration(%)60503040Meltﬂow index(gr/10min) (2308C,21.2N)6.017.934.1!0.01S.Sahin,P.Yayla/Polymer Testing24(2005)1012–10211013fourth groups of samples are coded as W1and W2,respectively.3.Mechanical testsUnless otherwise mentioned,all tensile tests were carried out at a crosshead speed of 50mm/min and,before testing,all samples were conditioned at room temperature for a period of 30days.All the results are average of three tests.The effects of processing parameters,masterbatch types and content and natural UV weathering on the properties of material were monitored using tensile,Charpy impact,Shore D hardness,and DSC tests.The details on these three tests were outlined elsewhere [10].3.1.Microstructural analysisAs the addition of any types of additives may alter the crystallisation characteristics of PP [13],a differential scanning calorimeter (DSC)analysis was used to evaluate thermal and morphological characteristics and the degree of crystallinity in the moulded samples containing different types of masterbatches at different concentrations.Tests were carried out on a Rheometric Scientiﬁc Polymer Laboratories instrument.Samples,each having a weight of about 13mg,were extracted from the middle sections of injection moulded samples,shown in Fig.1(c)of Sahin and Yayla [10].In the DSC tests,each sample was heated from 30to 2008C at a rate of 108C/min under a nitrogen atmosphere.Both thermal and crystallisation parameters were obtained from the heating scans.The level of crystallinity was calculated with the Eq.(1).c ZD H scc100(1)where D H sc is the melting enthalpy of the semi-crystalline material to be studied,and D H c is the enthalpy of 100%crystalline material.Since,a speciﬁc value of D H c for PP-Rdoes not exist,and the enthalpy of fusion for 100%crystalline polypropylene is almost independent of the isotacticity and equals 207J/g [14],the value of D H c for PP-R is taken as 207J/g.The melting temperature was taken as the peak temperature in the curves.The peak area,calculated automatically by the DSC instrument,was taken as the melting enthalpy.Typical thermal histories of some PP-R samples are given in Fig.1.It is evident that there is an endothermic melting peak in the heating scans.From the thermograms,it could be deduced that the onset of melting temperature is around 1108C and the melting point,the maximum of endothermic of melting peak in the scan,is around 1458C.From the ﬁgure,the crystallinity could be calculated as 30%.It has been demonstrated that there is very little difference between samples containing the natural and 1%of different colour masterbatches.Another important feature to be considered in Fig.1is that the DSC scans of all samples,namely natural,1%white colour masterbatch containing PP-R,white compound,W1and W2samples differ remarkably from each other,not only in their overall history but also in their melting temperature peaks.These variations are mainly due to the method that the samples are coloured,pounding or 1%masterbatch addition,and the way the samples are prepared,i.e.injection or extrusion.The cooling history of the extruded pipes and injected samples is rather different,resulting in some morphological variations in the samples.The early peaks and other multiple peak phenomena in the DSC tests are attributed to the compositional hetero-geneity of the crystal morphology of the polymer [15,16],and to lower-molecular weight polymer,which melted very early (i.e.wax,processing aid,dispersion aid)[17].3.2.Colouring effectsThe colouring of plastic products can be achieved easily by adding a small percentage of colour masterbatches during processing.To determine the effects of masterbatch concentration on the tensile properties of PP-R,tensile tests on samples containing 0.5,1,2.5,5and 10%masterbatches,detailed in Table 1,were carried out.Fig.2depicts the variation of yield stress with different colour masterbatch content.The ﬁgure shows that the addition of masterbatch diminishes the yield stress for masterbatch contents of up to about 0.5%.Moreover,the yield stress recovers with increasing the masterbatch content,and increasing the content enhances the yield stress as well.It is worth pointing out that the yield stresses of white,green and blue colour compounds are very comparable and more or less similar to that of 0.5%masterbatch samples.The decrease in the yield stress with masterbatch content is due to the high MFI value of the masterbatch (see Table 1).On the other hand,the recovery and increase in the yield stress is attributed to the reinforcing effect of pigments in the masterbatch [11],as well as the nucleating effects of these pigments [18,19].203550658095110125140155170185–1.8–1.5–1.2–0.9–0.6–0.30.00.3 Natural 1% White White W2 W1H e a t F l o w [m c a l /s ]Temperature [°C]Fig.1.DSC thermal history of natural and coloured PP-R showing remarkable inﬂuence of the method of colouring and the way the sample is prepared.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211014The last point in Fig.2to be mentioned is that the yield stresses of samples extracted from the pipe,namely W1and W2,are signiﬁcantly lower than that of the injection moulded test samples.The difference between W1and W2is thought to be mainly due to the method of colouring,and the differences between W1,W2and others are due to differences between the crystallisation histories of injection and extrusion of the samples.This is another illustrative example of the strong interrelationship between structure,processing,morphology and ﬁnal polymer [20].Fig.3shows the variation of yield strain with masterbatch content of the samples.The ﬁgure clearly reveals that adding the masterbatch reduces the yield strain,and this decline is almost linear for all masterbatch types.The yield strain also depends on colour compound and is much lower for the samples extracted directly from the pipe.The decline in yield strain as a function of masterbatch content is attributed to the reinforcing effect of pigments in the masterbatches.Y i e l d S t r e s s [N /m m 2]Masterbatch Content [%]Fig.2.Variation of yield stress with masterbatch contents for PP-R material.(The bars W,white colour compound;GN,green colour compound;B,blue colour compound;GR,grey colour compound;W1,White colour compound pipe;W2,1%white colour masterbatch containing pipe).Y i e l d S t r a i n [%]Masterbatch Content [%]Fig.3.Variation of yield strain with masterbatch contents for PP-R material.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211015The variation of Charpy impact energy with masterbatch content is shown in Fig.4,showing that for all types of masterbatches the total Charpy impact energies increase with masterbatch content up to 1%,after which the impact energy remains constant.However,the impact energy increases almost linearly with the white masterbatch content.Regarding the compounded samples,the green and blue compounded samples showed the highest impact resistance.Fig.4indicates more clearly that the inorganic based pigments (namely green,blue,and black compounds and masterbatch added samples)give better impactproperties than organic compounds (namely white,PP-R polymer).As pointed out elsewhere [10],the Charpy impact crack initiation and propagation resistance of the material are rather sensitive to the test temperature.The lower transition temperature is around 08C,and above 858C the material becomes too ductile to break.The present investigation made it clear that neither the content nor the type of masterbatch had any effect on this brittle-ductile transition.The effect of masterbatch content on melting tempera-ture,extracted from the DSC scans,is shown in Fig.5indicating that,except for the white masterbatch,addingC V [k J /m 2]Masterbatch Content [%]Fig.4.Variationof Charpy impact energy (C v )with masterbatch contents for PP-R material.M e l t i n g P o i n t [°C ]Masterbatch Content [%]Fig.5.Variation of melting point [T m ]with masterbatch contents for PP-R material.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211016masterbatch does not have a signiﬁcant inﬂuence on the melting point of the polymer.The melting points of coloured and compounded samples do not differ signiﬁ-cantly from each other.Fig.6indicates the volume percentage of crystallinity of compounded and coloured PP-R samples.It could be concluded from the ﬁgure that the addition of masterbatch and compounding diminishes the crystallinity and the level of crystallinity differs from one masterbatch to another,which could be attributed to the different level of nucleating activity of each pigment [18].Therefore,different types of pigments incorporated in PP-R result in different degrees of crystallisation.These results agree with the ﬁndings of Kening et al.[21]and Krisher and Marshall [22],which showed that incorporating pigments into PP affected its mechanical properties mainly in a positive fashion.3.3.Time effectsIt is known that the properties of the polymeric material may signiﬁcantly change just after conversion,i.e.by extrusion or injection processes.However,the history of this property change is not known for this material,so it is worth investigating what changes take place and how they depend on time.After injection moulding,the PP-R samples were conditioned at 228C and 50%relative humidity for a wide range of times—between 5min and 23months—in a box which excluded light.Fig.7shows the effect of storage time on yield strength and Charpy impact resistance of 1%white and 1%green masterbatch containing PP-R material.It is seen that the impact strength decreases considerably with storage time,and that it stabilizes about 30days after production.As for the yield stress,Fig.7shows that the yield stress increases gradually with storage time and that after around 30days itc [%]Masterbatch Content [ % ]Fig.6.Variation of crystallinity with masterbatch contents for PP-R material.05101520253035Conditioning Time [hour]σy [N /m m 2]C V [k J /m 2]Fig.7.Effects of storage time on yield stress (s y )and Charpy impact energy (C v )of 1%white and 1%green masterbatch containing PP-R material.Conditioning Time [hour]T m [°C ]c [%]Fig.8.Effect of storage time on melting temperature (T m )and crystallinity (c)of natural PP-R material.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211017remains fairly unchanged.The ﬁgure also reveals that time dependent tensile strength and impact resistance values are not sensitive to the type of masterbatch.The variation of melting temperature and crystallinity with storage time is shown given in Fig.8,indicating that both crystallinity and melting temperature increase with storage time and that both values stabilise after about 30days.Similarly,the variation of Shore D hardness with storage time is plotted in Fig.9,pointing out that the hardness increases gradually after the injection of the samples and remains relatively unchanged after more than 30days after production.Vicat softening temperature tests (VST)were utilised to determine the softening temperature of the material.A Zwick Vicat softening temperature tester at 50N force and 508C/h heating rate was utilised to determine temperature at which the indentor penetrates 1mm into the material.This value is particularly important for the conversion of the material into the product.The variation of VST with storage time is given in Fig.10,showing a minor increase with conditioning time for natural PP-R.3.4.Natural UV weatheringEvery polymeric material exposed to direct sunlight undergoes some damage.Plastic pipes made from PP-R could be used outdoors and thus may undergo ultraviolet (UV)degradation.This is especially the case for PP-R pipes used in solar heating systems.For this type of application,it is particularly important to decide what colour of PP-R pipe to use and how its mechanical properties deteriorate with the UV exposure time.Exposure of many plastics to ultraviolet radiation causes a loss in their mechanical properties.The mechanical property most severely affected is usually theV S T [°C ]Conditioning Time [hour]Fig.10.Effect of storage time on VST for natural PP-R material.H a r d n e s s (S h o r e D )Conditioning Time [hour]Fig.9.Effect of storage time on Shore D hardness for natural and 1%w white masterbatch containing PP-R material.50010001500200025003000350040004500500055000.00.51.01.52.02.53.03.54.0Januar 02December T m 5.3°C ϕm 85.9%October T m 16.7°C ϕm 70.4%September T m 21.7°C ϕm 66.8%November T m 11.2°C ϕm 74.4%August T m 24.6°C ϕm 73.3%July T m26.1°Cϕm 68.6%June T m 22.5°C ϕm 60.3%A b s o r b e d T o t a l S o l a r R a d i a t i o n E n e r g y [G J /m 2]Solar Exposure Time [hour]Fig.11.Absorbed total solar radiation energy variation as a function of UV exposure time considered in this study.T m and 4m represent the average temperature and humidity,respectively.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211018ductility of the material [23].Pigment systems,on the other hand,inﬂuence to what extent materials are affected by ultraviolet radiation exposure.Some colours,such as black,may make the material less susceptible to ultraviolet radiation degradation than others [24].Several series of tensile,Charpy impact,Shore D and DSC tests were carried out on test samples exposed to sunshine for different times,up to six months during the summer time.All samples were suspended so that they could freely rotate,enabling each surface to be UV affected uniformly.Fig.11shows the total absorbed energy as a function of exposure time.The variation of tensile properties with exposure time is shown in Fig.12.The ﬁgure reveals that both yield stress and yield strain decreases with UV exposure time for all samples.Most signiﬁcantly,the greatest decrease is seen in the natural PP-R.The least UV affected sample is the PP-R containing 1%black masterbatch.The effect of natural UV weathering time on the Charpy impact resistance of PP-R material is shown in Fig.13,showing that for all the samples the Charpy impact energydiminishes with the UV exposure time.However,black samples are the least and natural samples the most affected.Fig.14shows the variation of the Shore hardness with UV exposure time.The ﬁgure shows that just after the beginning of natural UV exposure,the hardness of the samples increases with exposure time for all samples.It is also worth mentioning that the least affected are the natural colour samples,which have higher opacities.The hardness increase in blue and green samples is pronounced.Black samples are exceptions,mainly due to the carbon black content of the masterbatch.As stated by Turton and White [24],pigments that simply reﬂect or scatter UV,preventing it from penetrating far into the plastics,also limit degradation to a region close to the surface.Fundamental studies in the area of polymer morphology almost universally employ DSC.Thermal analysis has also played a signiﬁcant role in the degradation studies of semicrystalline polymers [25].DSC tests on UV degraded samples could be a good indication of morphologicalWeathering Time [hour]εy [%]σy [N /m m 2]Fig.12.Natural UV weathering time effect on yield stress (s y )and yield strain (3y )of natural and 1%coloured PP-R material.Weathering Time [hour]C V [k J /m 2]Fig.13.Natural UV weathering time effect on Charpy impact strength (C v )of natural 1%coloured PP-R material.Weathering Time [Hour]H a r d n e s s [S h o r e D ]Fig.14.Natural UV weathering time effect on Shore D hardness of natural and 1%coloured PP-R material.7085100115130145160175190–1.6–1.1–0.6–0.10.40.90 hour 504 hour 2304 hour 4776 hourH e a t F l o w [m c a l /s ]Temperature [°C]Fig.15.Natural UV weathering time effect on the DSC thermal history of natural PP-R material.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211019changes in the material.The DSC scans obtained in this study show that the degree of UV degradation sensitivity differs from one colour to other.From the comparison of Figs.15–17,it could be deduced that the most affected sample is the natural (Fig.15)and the least effected ones are the black,blue (Fig.16),white (Fig.17)and green coloured samples,respectively,showing strong structural modiﬁ-cations due to UV degradation.This dependence is attributed to the fact that the different pigments used in the masterbatches have different UV absorption/screening mechanisms,resulting in different protective mechanisms against UV exposure [26,27].The effect of adding different colour masterbatches on the UV performance of PP-R material was also evaluated using the melt ﬂow index (MFI)study.MFI was measured at 2308C at 21.6N according to ISO 1133standard on UV exposed samples containing 1wt%blue,black,green and white colour masterbatch.For the sake of comparison,the variation of MFI with exposure time for natural PP-R was also measured.The results in Fig.18show that natural andgreen samples were the most affected and black,blue and white samples were the least UV affected.The results of these MFI measurements correlate with the DSC results in Figs.15–17.The increase in MFI is attributed to the chain scission and formation of new groups [25].4.ConclusionsThe results of the present investigation indicate that the way the test samples are produced,i.e.injection or extrusion,strongly inﬂuences the overall mechanical properties of polymers.Mechanical and DSC tests showed that both the type and content of masterbatches in PP-R inﬂuence not only the degree of crystallinity but also the structure and mechanical properties of the polymer.The addition of colour masterbatches increases the short term yield stress and impact strength but reduces the yield strain .The yield and Charpy impact resistance of both natural and 1%masterbatch containing PP-R material continuously vary during the room temperature conditioning period of about 30days,and then remain fairly constant.The property changes in mechanical and thermal properties,particularly in yield strength and Charpy impact resistance,after the injection moulding could not solely be explained through ‘post-crystallisation’.Apart from the slight variation in crystallinity,the inﬂuence of the polymer parameters ﬁxed in the synthesis,namely average molar mass,molar mass distribution and chain regularity [28]as well as the reduction of free volume of the amorphous phase has to be taken into account [29].For all naturally aged PP-R samples coloured in different ways the yield strength,yield strain and Charpy impact energy decrease with increasing natural UV weathering time.Shore D hardness,on the other hand,increased with the degradation time.Tensile and impact properties were affected mostly by UV in samples having higher opacities.7085100115130145160175190–1.7–1.5–1.3–1.1–0.9–0.7–0.5–0.30 hour 504 hour 2304 hour 4776 hour H e a t F l o w [m c a l /s ]Temperature [°C]Fig.16.Natural UV weathering time effect on the DSC thermal history of 1%blue coloured PP-R material.Weathering Time (hour)M F I (g r /10 m i n )Fig.18.Effect of natural UV weathering time on the variation of MFI values for PP-R material containing 1%white,green,blue and black masterbatch and natural PP-R.7090110130150170190–2.0–1.5–1.0–0.50.0504 hour 2880 hour 4320 hour H e a t F l o w [m c a l /s ]Temperature [°C]Fig.17.Effect of Natural UV weathering time on the variation of DSC melting curves for PP-R material containing 1%white masterbatch.S.Sahin,P.Yayla /Polymer Testing 24(2005)1012–10211020Morphology,crystallization and melting behaviour is also affected by the addition of masterbatch to a degree which depends on masterbatch type.This study provides a clear view of the inﬂuence of masterbatch type and content on both mechanical proper-ties.Similarly,the UV degradation of the PP-R is very much masterbatch,thus pigment,dependent,making it clear that pigments vary in their UV stability.With this work it is evidenced that the MFI tests on UV degraded samples are quite useful to assess the extent of degradation.This has practical implications for durability assessment and stabil-ization strategies.AcknowledgementsWe are greatly indebted to colleagues at both industrial as well as university laboratories for their positive interest, and especially to Turkkablo A.O.,Emas A.S.,and Pipelife A.S.The raw materials supplied by Borealis S.A.are gratefully acknowledged.Dr P.S.Leevers of Imperial College UK,and Prof.Dr E.Cavusoglu of Arili Plastik of Turkey are also appreciated for their valuable discussion and comments on the manuscript.References[1]G.Beer,Polypropylen(PP),Kunststoffe86(10)(1996)1460–1463.[2]R.L.Gray,R.E.Lee,Inﬂuence of co-additive interactions onstabilizer performance,ANTEC’96(1996)2683–2687. 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March 30, 2012China Petroleum Processing and Petrochemical Technology2012,V ol. 14, No. 1, pp 15-19Scientific Research1　IntroductionSince 1959 Jack H. Schulman and his co-workers pro -posed the word ‘microemulsion’, there have been exten -sive studies done on microemulsions in the last few de-cades. Microemulsions are optically isotropic, transparent, and thermodynamically stable homogeneous solutions of oil and water, stabilized by addition of a surfactant which is usually coupled with a cosurfactant. The droplets of microemulsions are in the 10—100 nanometer range [1-4].Paraffin wax emulsion is one of the most important spe -cial wax products, and it is prepared by paraffin wax and several different types of emulsifiers and finally all com -ponents form a stable and multiphase emulsion consisting of solid emulsifier, oil and water. This paraffin wax mi -croemulsion can flow freely and can be used without be -ing melted or dissolved in solvent. However, the study on emulsifying wax in our country and production areas is still in the initial stage, characterized by few assortments, poor quality, and small scale that cannot meet the needs of various industries. Therefore a part of wax emulsion products also rely on imports. Besides, coarse particle size and poor stability lead to constraints in the applica -tion of paraffin wax emulsion. The study on the paraffin wax microemulsion, on the one hand, can improve the quality of existing products, and on the other hand, can open up new fields of its applications.2　ExperimentalMaterials and Instruments: The fully refined paraffin wax No.58—60 were provided by the Beijing Yanshan Petro-chemical Company. Fatty alcohol-polyoxyethylene ether, anionic surfactant, KOH and medium-chain alcohols were all chemically pure reagents. The JJ-1 electric mixer was made by the Jintan Medical Instrument Factory. The HH-S water bath pot was made by the Yuhua Instrument Company. The TGL-16 high-speed centrifuge was made by the Changzhou Guohua Electric Appliance Co., Ltd. The LS13320 laser particle size analyzer was made by the Beckman Coulter Co., Ltd.Preparation of the Paraffin Wax Microemulsion: The paraffin wax and emulsifier were put in a beaker, which was heated at 80 ℃, and mixed well at a slower stirringCorrresponding Author: Professor Li Fengyan, Telephone: +86-10- 88583326 ; E-mail: lifengyantd@.Effects of Preparation Parameters on ParaffinWax MicroemulsionDai Danghui 1; Li Fengyan 2; Zhao Tianbo 3(1. Department of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029; 2. Department of Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617;3. Department of College of Science, Beijing Institute of Technology, Beijing 100081)Abstract: The paraffin wax microemulsion was prepared from fully refined paraffin wax No.58—60 in the presence of a nonionic surfactant and an anionic surfactant. The influence of manufacturing parameters on the particle diameter of paraf -fin wax microemulsion included the quantity of the emulsifier, the temperature and emulsification time, the stirring speed, the pH value and the auxiliary ingredient (cosurfactant). The test results showed that the temperature of emulsification had little effect on the particle size of paraffin wax microemulsion in a temperature range of 75—85 ℃. Other manufacturing parameters all had a great effect on the particle size of paraffin wax microemulsion. The optimum preparation conditions in -cluded: a w (emulsifier) of 6%, an emulsification temperature of 80 ℃, an emulsification time of 40 min, a pH value of about 8, and a stirring speed of 600 r/min, with n -amyl alcohol serving as the co-surfactant. Under these conditions, a translucent and baby blue paraffin wax emulsion was prepared with its particle size equating to 97 nm.Key words: paraffin wax; microemulsion; particle diameter; influencing factorsChina Petroleum Processing and Petrochemical Technologyspeed (a). The co-surfactant was at first added in the wa-ter and mixed well with glass rod, and then the mixture was preheated in the water-bath pot until the temperature reached 70 ℃ (b). Some of the mixture (b) was added to the oil phase (a) slowly so that the mixture would form a W/O emulsion under stirring for 25 minutes. And then the remaining mixture (b) was added faster to the mixture un-der stirring for 15 min, so that the previous W/O emulsion would be transformed into an O/W emulsion.Solid Content Measurements: 2 g of sample was weighed in a weighing bottle, and was then dried in a loft drier for 2 hours at 105 ℃. Then the dried sample was weighed again with the solid content expressed by Eq. 1[5]:Solid content=sample mass after drying/sample mass before drying×100% (1) Determination of Stability: The emulsion was put in the sample tubes and was then subjected to high-speed cen-trifugalization for 30 minutes at a centrifugal speed of 3 000 r/min. The ratio of water to oil was recorded to measure the stability of the emulsion. The emulsion scores were measured according to the ratio of water to oil in the emulsion (Table 1). The equation for calculating the ratio of water to oil is shown in Eq. 2:The ratio of water to oil=volume of water phase/total volume of emulsion×100% (2)Table 1　Stability ScoringRatio of water in oil, %Score010<10910—15815—20720—25625—30530—35435—40340—45245—501Emulsion free0 Particle Size Measurements: The particle size was mea-sured at room temperature using the LS13320 laser particle size analyzer. One or two drops of paraffin wax microemulsion were added into the instrument and the particle size distribution curves were recorded after the measurements.Determination of Dispersion[6]: The dispersion of the emulsion was determined by measuring the concentrated emulsion and was divided into five grades with a decreas-ing order: 1>2>3>4>5.3　Results and Discussion3.1 E ffect of emulsifier amount on paraffinwax microemulsionFigure 1 shows the particle size distribution of the emul-sion when the mass fraction of the emulsifier was 4%, 5%, 6% , 7%, and 8%, respectively. It can be seen from Figure 1 that the quantity of emulsifier had a great in-fluence on the particle size of the emulsion. When the emulsifier amount was less, for example 4%, the particle size was bigger and its distribution was not concentrated. However, at an excessive amount of emulsifier (8%), the viscosity of the emulsion was increased with poor flow property, and its average particle size reached up to 180 nm. The average particle size of emulsion reached 97 nm, when the emulsifier amount was 6% which had attained abest performance of the emulsion.Figure 1　Effect of quantity of emulsifier on the particlediameter of paraffin wax emulsion▲—4%; ▼—5%;■—6%;—7%; ●—8%3.2 E ffect of the emulsifying temperature onparaffin wax microemulsionFigure 2 shows the particle size distribution when the emulsifying temperature was 70 ℃, 75 ℃, 80 ℃, and 85 ℃, respectively. The particle size was the smallest at 80 ℃and was equal to 97 nm. The emulsifying temperature had little effect on the paraffin wax microemulsion in the tem-2012,14(1):15-19perature range of 70 ℃ to 85 ℃, but the property of non-ionic surfactant was influenced by temperature. It is well-known that the increase of temperature makes non-ionic surfactants more hydrophobic (with appearance of cloud point) while ionic surfactants become hydrophilic[7]. Hence a nonionic-anionic surfactant mixture, whose prop-erties are temperature insensitive, has been suggested[8]. Figure 2　Effect of temperature on particle diameter ofparaffin wax emulsion▼—70 ℃; ▲—75 ℃;—80 ℃;●—85 ℃3.3 E ffect of emulsifying time on paraffin waxmicroemulsionFigure 3 shows the particle size distribution when the emulsifying time was 30 min, 40 min, and 50 min, re-spectively. If the emulsification time was too short, the paraffin wax would not be fully emulsified. If the particle size of the emulsion is large, the distribution is broader and the particles would be prone to coalescence. The larger the range of the emulsification time is, the weaker the stability of emulsion would be. If the stirring of emul-sification mixture was continued, the coalescing particles in emulsion will disperse gradually to form uniform and exquisite emulsion. The particle size would reach 97 nm when the emulsifying time was 40 min.3.4 E ffect of stirring speed on paraffin waxmicroemulsionFigure 4 shows the particle size distribution when the stirring speed was 400, 600, and 800 r/min, respectively. The stirring speed had a great influence on emulsion formation. If the stirring speed was too low, the paraffin wax and emulsifier would not be mixed thoroughly and the emulsion particles will be uneven because of lack of necessary shear force. However, if the stirring speed was too fast, there would be a large number of air bubbles involved, and it would be difficult to defoam the liquid mixture, resulting in an inferior emulsion quality. Hence a suitable stirring speed should make the particles of the emulsion uniform in size. After the relevant investigation▼—40 min; ▲—50 min▲—30 minFigure 3　Effect of emulsifying time on the particle diameterof paraffin wax emulsionFigure 4　Effect of the stir speed on the paraffin waxemulsion particle diameter▼—400 r/min; ▲—600 r/min;●—800 r/minDai Danghui, et al. Effects of Preparation Parameters on Paraffin Wax MicroemulsionChina Petroleum Processing and Petrochemical Technologywas performed, a stirring speed of 600 r/min was consid-ered to be more appropriate.3.5 E ffect of pH value on paraffin wax mi-croemulsionFigure 5 shows the particle size distribution in paraffin wax microemulsion when the pH value of emulsion was 6, 7, 8, 9, and 10, respectively. The particle size was the smallest and was equal to 97 nm when the pH value was 8 for the formation of the required paraffin wax micro-emulsion. When the pH value decreased or increased beyond this value, the particle size of microemulsion would also increase, because the anionic surfactant used in experiments was stable in a weakly alkaline medium. Under acidic conditions, the anionic surfactant was prone to hydrolysis, while in a neutral medium, the autocata-lytic hydrolysis would lead to hydrolysis of the anionic surfactant. Therefore the surfactant mixtures would retain higher activity and stability when the pH value of the so-lution was 8.Figure 5　Effect of pH value on particle diameter of paraffinwax microemulsionpH value:▼—6;—7;■—8;●—9;▲—103.6 E ffect of cosurfactant on the particle sizeof paraffin wax microemulsionFigure 6 shows the particle size distribution when etha-nol, n-butyl alcohol, n-amyl alcohol, and n-hexyl alcohol, respectively, was used as the co-surfactant. In the previ-ous studies, medium-chain alcohols have been mainly used as cosurfactants. The cosurfactant is mainly parti-tioned between the surfactant layer and the oil domain inside the microemulsion phase. Since the solubility of the cosurfactant in the oil domain is fairy large, the appar-ent solubilizing capability of the mixed surfactant (ionic surfactant + cosurfactant) is low. To avoid the loss of cosurfactant, a long-chain alcohol should be used. How-ever, since lamellar liquid crystals are formed over a wide range of temperatures in a mixed system of ionic surfac-tant and higher alcohol, it is difficult to produce isotropic fluid microemulsions. The combination of ionic surfactant and lipophilic poly(oxyethylene) type nonionic surfactant is considered to be a good candidate for creating micro-emulsions. In this study, n-amyl alcohol was the best co-surfactant, resulting in a dominant microemulsion particlesize of 97 nm.Figure 6　Effect of the cosurfactants on the paraffin waxemulsion particle diameter▼—ethanol;—n-butyl alcohol;▲—n-amyl alcohol; ●—n-hexyl alcohol4　ConclusionsIn case o f paraffin wax microemulsion formation using the system consisting of fatty alcohol-polyoxyethylene ether, anionic surfactant, and n-amyl alcohol:(a) The temperature of emulsification had little effect on the particle size of paraffin wax microemulsion in the temperature range of 75—85 ℃. The other manufacturing parameters all had a great influence on the particle size of paraffin wax microemulsion.(b) Optimum conditions for microemulsion formation included: a w (emulsifier) of 6%, an emulsification tem-perature of 80 ℃, an emulsification time of 40 min, a pH value of about 8, and a stirring speed of 600 r/min, with n-amyl alcohol serving as the co-surfactant.(c) Under the afore-mentioned conditions, a translucent and baby blue pa raffin wax emulsion with a particle size2012,14(1):15-19of 97 nm had been prerpared. Acknowledgements: This work was supported by The National Natural Science Funds (Project No. 21076025).References[1]　H uh C. Interfacial tensions and solubilization ability of amicroemulsion phase that coexists with oil and brine [J]. J.Colloid Interface Sci, 1979, 71(2): 408-426[2]　B arakat Y, Fortney L N, Schechter R S, et al. Alpha olefinsulfonates for enhanced oil recovery [C]. Proc of the Sec-ond European Symposium on EOR, 1982: 11-20[3]　B arakat Y, Fortney L N, Schechter R S, et al. Criteria forstructuring surfactants to maxmizing solubilization of oil and water. Part 2. Alkyl benzene sodium sulfonates [J]. J Colloid Interface Sci, 1983, 92(2): 561-574[4]　B ellocq A M, Bourbon D, Lemanceau B, et al. Thermody-namic, interfacial, and structural properties of polyphasic microemulsion systems [J]. J Colloid Interface Sci, 1982, 89(2): 427-440[5]　C hen Shu, Xiao Qing, Chen Hongming. Synthesis andapplication of modification anionic micro-emulsion [J]. Ji-angxi Chemical Industry, 2007 (3): 91-93 (in Chinese) [6]　Q uan Hongping, Huang Zhiyu, Liu Chang. Preparation ofhigh wax emulsion and investigation on affecting factors [J].Advances in Fine Petrochemicals, 2007(4): 43-45 (in Chinese) [7]　S chubert K V, Busse G, Strey R, et al. Microemulsions withformamide as polar-solvent [J] . J Phys Chem, 1993, 97(1): 248[8]　K unieda H, Hanno K, Yamaguchi S, et al. The three-phasebehavior of a brine / ionic surfactant / nonionic surfactant / oil system: Evaluation of the hydrophile-lipophile balance (HLB) of ionic surfactant [J]. J Colloid Interface Sci., 1985, 107(1): 129-137Dai Danghui, et al. Effects of Preparation Parameters on Paraffin Wax MicroemulsionAcceptance Test of Biomass Based DME Demonstration Unit at Guangzhou Energy InstituteThe international science and technology cooperative project, “The key technique and demonstration project for fuel synthesis based on biomass gasification”, which is sponsored by the Science and Technology Ministry of PRC and undertaken by the CAS Guangzhou Institute of Energy has passed the acceptance test of relevant departments. The continuous and stable operation tests of this pilot scale demonstration unit have revealed that 6—7 tons of biomass can produce one ton of dimethyl ether (DME). The composite gasification rate of biomass was ≥80%, and the once-through conversion of biomass to DME reached ≥70%, with DME selectivity reaching ≥90%.This institute after importing the advanced Italian tech-nology for biomass gasification with oxygen-enriched air has completed an optimized design of biomass gas-ification system and fuel gas clean-up system and set up a pilot-scale demonstration unit for fuel synthesis based on biomass gasification. When this project was of-ficially launched in 2008, the research team has engaged in innovative research work regarding the technique for biomass gasification with oxygen-enriched air, technol-ogy and equipment for cleaning of raw syngas through catalytic reforming and gas components adjustment, and process and catalysts for synthesis of DME from bio-mass derived syngas, and eventually worked out a 300 Nm3/h biomass syngas reforming and adjusting system in the presence of oxygen containing stream. The said system features a lot of functions such as the high-tem-perature settling by inertia, reforming and clean-up of tar and gas components adjustments in the catalyst bed, the high-temperature waste heat utilization, the low-temperature filtration of gas and the high-efficiency dust remover after cleanup of tar. Furthermore, a bifunctional CuZnAl/AlOOH catalyst with homogeneous structure and composition has also been developed.The synthesis of DME through biomass gasification is an indirect liquefaction technique, which is character-ized by high feedstock adaptability, high purity of prod-uct, absence of NO x and SO x emissions after combustion of DME that has been garnering worldwide attention amid escalating prices of petrochemical resources.。