SHS 01009-92 管壳式换热器维护检修规程

Maintenance and Service Procedure for Petr

ochemical Equipment--

General Equipment

Maintenance and Service Procedure for Shell and Tube Heat Exchang er

（管壳式换热器爱护检修规程）

SHS 01009-92

(For Trial Implementation)

Promulgated by SINOPEC

SINOPEC Publishing House

Contents

1 General 2

2. Period and Content of Maintenance 2

3. Maintenance and Quality Standard 3

4. Testing and acceptance 9

5. Service and Troubleshooting 12

1 General

1.1 Subject and scope

1.1.1 This procedure specifies the period and content of maintenance, maintenance and quality standard, testing and acceptance, and service and troubleshooting of heat exchanging equipment.

1.1.2 This procedure is applicable to the petrochemical steel shell-and -tube heat exchangers like fixed tubesheet exchanger, floating-head exchan ger, U-tube exchanger etc., and kettle-type reboilers, with operating pressu re below 35Mpa.

1.1.3 The service of pressure elements shall comply with SHS01004-92 “Maintenance and Service Procedure for Pressure Vessels”

1.1.4 References

SY21003-73 Maintenance and Service Procedure for Heat Exchang er in Oil Refinery

GB151-89 Steel Tubular Exchanger

2. Period and Content of Maintenance

2.1 Maintenance period

The maintenance interval can be determined by individual enterprise according to the features of its production equipment.

2.2 Maintenance content

2.2.1 Cleaning tube bundle and shell.

2.2.2 Welding joint and expanded joint treatment of tube bundle and the replacement individual tube.

2.2.3 Check and repair the tube box, front and back cover, small and big floating heads, and fittings etc., as well as their seal faces, replace g askets and test with pressure.

2.2.4 Replace some of the bolts and nuts.

2.2.5 Repair the thermal insulation of the shell and make anticorrosio n treatment

2.2.6 Replace the tube bundle or the shell.

2.2.7 Replace the shell.

3. Maintenance and Quality Standard

3.1 Preparations prior to Service

3.1.1 Have full knowledge of the operation conditions, and make all the necessary drawings and documents at hand.

3.1.2 Prepare all the necessary service tools, test stand, clamping app aratus etc.

3.1.3 Displace and clean out the internal fluid, to meet the requireme nts of safety service.

3.2 Content of the inspection

3.2.1 Clean the tube bundle and shell.

3.2.2 Inspect visually the shell, tube bundle, and components for any corrosion, crack, deformation, etc. Have a spot check with surface flaw detection, if necessary.

3.2.3 Inspect the anticorrosive coating for any sign of aging and peel ing off.

3.2.4 Inspect the lining for any corrosion, swell, fold, and crack.

3.2.5 Check the seal faces and the gaskets.

3.2.6 Check the wear condition of the fasteners. Clean and examine t he high-pressure bolts and nuts one by one, and carry out surface nondest ructive inspection if necessary.

3.2.7 Inspect the foundation for any settlement, inclining, damage and crack. Check its anchor bolts and pats to see if they are loosened and d amaged.

3.3 Maintenance quality standard

3.3.1 The scaling on the inner and outer surface of the tube bundle shall be cleaned out.

3.3.2 In case there is a partition plate in the tube box, its gaskets sh all be machined monolithically, and shall be free of any defects that may affect the sealing.

3.3.3 When blocking leaking tubes of tube bundles, on the same tube side, the number of tubes being blocked to stop leaking shall not exceed 10% of the total number of the tubes. Within the allowed range of proc ess index, the number of blocked tubes may be increase by an appropriat

e amount.

3.3.4 All the parts and components used shall conform to the relevan t technical specifications, and shall be provided with certificate of complia nce for materials.

3.3.5 Replacing tube bundles

3.3.5.1 The tube surface shall be free of such defections as cracks, f olds, double-skin, etc.

3.3.5.2 When it is necessary to splice the tubes, only one welding jo int as maximum is allowed on the same heat exchanging tube (U-tube ma y have two welding joints). The minimum tube length shall be no less th an 300mm and no welding joints for splicing shall not be allowed within the elbow section of U-tube, while the length of straight tube section sh all be no less than 50mm, and the unfitness of butt joint shall not excee

d 15% of th

e tube wall thickness and not be greater than 0.5mm.

3.3.5.3 Test the hardness of the tubes. Normally it is required that th

e hardness o

f the tube shall be 30HB lower than that of the tube sheet. I n case the tube hardness is higher than or closer to the tubesheet hardnes s, the annealin

g treatment shall be made to the two ends of the tubes. T

h e tube length subjected to the annealing treatment shall be 80mm~100mm longer than the thickness of the tube sheet.

3.3.5.4 The ends of the tube shall be clean and free of grease and d irt, and shall not have any defects that may affect the tightness of the ex panded joints, such as penetrated, longitudinal or spiral scores.

3.3.5.5 The both ends of tubes shall project beyond the tube sheets, and the length of the tube ends projected from the tube sheets shall be 4 1mm.

3.3.5.6 The degree of expanded tube joint shall be within the range of 0.7~1.6%.

(d’ID –dID) –(d0 –d)

Degree of expanded tube joint = 10 0%

d0

where: d’ID the inside diameter of the tube after expanded for joint;

dID the inside diameter of the tube before expand ed for joint ;

d th

e outside diameter o

f the tube before expanded for joint ;

d0 t he aperture of the tubesheet before expanded for joint.

3.3.5.7 The expanding operation should not be carried out at a tempe rature below 0oC. After expansion, the expanded section and the transitio n section of the tube shall be smooth, without any crack and groove. The re-expansion of each expand shall not exceed twice.

3.3.5.8 When welding the tube and tubesheet together, the surface of the cut on the tube shall be smooth, and free of burrs, convex and conc ave, crack and lamination, and the position for welding shall be free of s

uch foreign matters as slag, iron oxide and greasy dirt, which may affect the welding quality.

3.3.6 The integral replacement of the tube bundle shall be carried out according to GB151-89 “Steel Tubular Exchanger”or the requirements of design drawing.

3.3.7 The repair of the shell shall be made according to SHS01004-9

2 “Maintenance and Service Procedure for Pressure Vessels”

3.3.7.1 After repair welding, the steel plate, which has been heat-treat ed before, shall be retreated.

3.3.7.2 Pass the pressure-tight test or air-tightness test.

3.3.7.3 Data and records are complete.

3.3.8 The replacement of gaskets shall comply with the design requir ements, or refer to Table 1.

Note: ①Benzene can dissolve the acrylonitrile rubber in the oil-resis tant rubber asbestos gasket, therefore PN≤2.5MPa.

②For benzene medium with temperature lower than or equal t o 200oC, the wound type gasket shall also be used.

③It is not suggested to select the non-metal soft gaskets for the internal connection of floats, etc.

④Wound type gasket or clad rubber asbestos plate should be selected for the inflammable, explosive, poisonous, and easy permeable m edia.

⑤The wound type gasket normally is not applicable to the fla nge with flat facing.

3.3.9 When it is necessary to replace the bolts and nuts on the exch anger, they shall be selected and used according to the design requirement s or with reference to Table 2.

3.3.9.1 The threads shall be free of burrs and flaws. Thread with slig ht local fracture shall not exceed 1/4 of one turn, and the total length of such thread shall not exceed one turn.

3.3.9.2 For bolts with operation temperature over 250oC, the anti-occl usion agent shall be applied during the assembling.

3.3.10 Cold exchanging equipment with anticorrosive coating

3.3.10.1 Check the coating of water coolers visually, and make sure t he surface is smooth, without any phenomenon of dripping, flow, missing coating, etc.

25Cr2MoV A 30Cr2MoA - 20 ~ +500 25Cr2MoV A - 20 ~ +550 1Cr5Mo 1Cr5Mo - 20 ~ +600 2Cr13 1Cr13, 2Cr13 - 20 ~ +450 0Cr19Ni9 25Cr2MoV A - 20 ~ +550 0Cr19Ni9 - 196 ~ +700 0Cr17Ni12Mo2

0Cr17Ni12Mo2

- 196 ~ +700

3.3.10.3 When handling, installing, servicing and cleaning the equipm ent, care shall be taken not to damage the anticorrosive coating.

4. Testing and acceptance 4.1 Testing

4.4.1 The service records shall be complete and correct.

4.1.2 The construction unit shall confirm that the quality is acceptabl e, and conditions for test are fulfilled.

4.1.3 Pressure test

4.1.3.1 The test value shall adopt the larger one obtained from the f ollowing formulas:

a. Hydraulic pressure test value

PT = ?????

+1

.0][][25.1P P

t σσ

b. Air pressure test value

PT = ?????+1

.0][][15.1P P

t σσ

Where: PT the test value of pressure-tight test, MPa;

P the maximum operating pressure of the tube side

or shell side, MPa;

[

] the allowable stress of the material under test te

mperature, MPa;

[ ]t the allowable stress of the material under the ope rating temperature,

Mpa;

[

]

[ ]t

4.1.3.2 When making the pressure test, the pressure shall be increase d gradually to the specified value. Holding time of constant pressure for l ow-pressure heat exchanger shall not be less than 5min, for medium and high pressure heat exchanger shall not be less than 20min. Then, reduce to the operating pressure and make careful inspection. Exchangers withou t fracture, leakage and residual deformation will be taken as qualified. If there are problems as leakage etc., the exchanger shall be re-tested after t he remedy is made.

4.1.3.3 Sequence and requirements of pressure test 4.1.3.3.1 Fixed tubesheet exchanger

a. Pressure test of shell side: check the shell body, the joints to conn ect heat exchanging tubes with the tube sheet, and other related positions.

b. Pressure test of tube side: check the tube box and other related p ositions.

4.1.3.3.2 U-tube exchanger, kettle-type reboiler (with U-type tube bun dle) and stuffing box exchanger

a. Pressure test of shell side (use the proving ring): check the shell body, tube sheet, the connections between heat exchanging tubes and tube plate, and other related positions.

b. Pressure test of tube side: check the related positions of the tube box.

4.1.3.3.3. Floating heat exchanger, kettle-type reboiler (with floating-h ead tube bundle)

≥ 1.8, the value 1.8 will be taken for the calculation.

When

a. Make pressure test to the connections between the tubes and tubes heet with proving ring and special pressure test tools for floating head. F or kettle-type reboiler, a special shell for pressure test on the connections between the tubes and tubesheet shall also be used, in order to check th e connections between heat exchanging tubes and the tube sheet, and the related position.

b. Pressure test of tube side: check tube box, floating head and the r elated positions.

c. Pressure test of shell side: check the shell body, connections betwe en heat exchanging tubes and tube plate, and the related positions.

4.1.3.3.4 When test pressure of the tube side is higher than that of t he shell side, the pressure test of connections shall follow the specificatio n on the drawing, or the method agreed by both the production unit and the construction unit.

4.1.3.3.5 Overlapping heat exchanger

The pressure test for joints shall be carried out on the unit-by-unit b asis. When the ranges of sides for each heat exchanger are jointed togeth er, the pressure test of tube side and shell side shall be carried out after the overlapping assembling. Check the seal on the connecting flange.

4.2 Acceptance

4.2.1 After the equipment has been put into operation for one week, all the indexes shall reach the technical requirements or meet the producti on needs,

4.2.2 The anticorrosion of the equipment is well preserved without an y damage, and meets the standard of intact.

4.2.3 Submit the following technical documents

4.2.3.1 Notices for design change and material substitution, and the c ertificates of compliance for materials and parts.

4.2.3.2 Service records.

4.2.3.3 Inspection report on the quality of welding joints (including v isual inspection and nondestructive test).

4.2.3.4 Test records.

5. Service and Troubleshooting

5.1 Routine maintenance

5.1.1 Carefully check the operation parameters of the equipment. Ove r-temperature and over-pressure are strictly prohibited.

5.1.2 The operator shall strictly observe the safety operation proceudr es, conduct regular tour inspection to the heat exchanging equipment, to c heck for the stability of its foundation and supports, and the leaking of t he equipment.

5.1.3 When the cold exchanging equipment with anticorrosive coating is under operation, the temperature shall be strictly controlled in order to avoid the damage to the coating.

5.1.4 Maintain the completeness of the insulation.

5.1.5 Painting the equipment periodically to prevent corrosion.

5.2 Common troubles and troubleshooting (see Table 3)

Additional Note:

Jinxi Refinery and Petrochemical Plant is responsible for the draft of this procedure.

The draftsman of this procedure is Mr. Xu Zhongliang.