世界最大海水淡化项目——以色列Ashkelon

Element type TDS Feed Boron Feed Temperature pH Feed Recovery % mg/L mg/L °C
BW30-400 1,500 – 5,500 5.0 – 10.0 19 – 32 6.0 – 6.5 > 85
Normalized flow (relative) Design flow @ start-up Sep-05 Oct-05 Nov-05 Dec-05
世界上最大的海水淡化项目 以色列Ashkelon
王大新 July, 2007
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内容
• • • • • 硼的化学特性 高pH条件下硼的脱除率 工艺流程介绍 系统的性能 总结
200
Performance data TDS product Boron product Feed pressure mg/L mg/L bar 25 – 120 3.0 – 6.5 8.5 – 12.0
150
100
50
Normalized salt passage (relative) Design salt passage @ start-up
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4段透盐率
200 normalized salt passage (relative) (relative) (%) 180 160 140 120 100 80 60
高pH条件下硼的脱除率
Boron vs. pH
100 % presence 80 60 40 20 0 7 8 9 pH 10 11 H3BO3 H2BO3-
H3BO3 ↔ H+ + H2BO3反渗透系统对没有电荷的分子脱除率低！
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总出水量已经突破100,000,000吨
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7
以色列Ashkelon330,000 吨/天海水淡化项目：
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8
原水含盐量40,000ppm 硼 4.8 – 6.3ppm 海水
Performance data TDS product Boron product Feed pressure mg/L mg/L bar 2 – 11 <0.24 7.3 – 11.0
RO2-1
Sep-05
Oct-05
Nov-05
• 透盐率小于设计透盐率 • 随着温度的降低透盐率还在降低
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最终产水 第一段 前级产水 20%
- CO2 + NaHCO3
第二段
产水 70% 产水
- CO2 + NaHCO3
含盐量<40ppm 硼<0.35ppm
浓水第一段
浓水第二段
酸
第三段
第四段
后级产水
浓水第三段
浓水第四段
10 %
SW30HR LE-400
BW30LE-440
BW30-400
BW30LE-440
段内分级产水（两端产水）设计
进水
20%产水
80%产水
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一段海水膜堆端头
4段产水量
120 Normalized permeate flow (relative) (%) 100 80 60 40 20 0 Aug-05 Normalized flow (relative) Design flow @ start-up Sep-05 Oct-05 Nov-05 Dec-05 RO4
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2段产水量
130 Normalized permeate flow (relative) (%) 120
Normalized flow (relative) Design flow @ start-up Sep-05 Oct-05 Nov-05 Dec-05
• 调整期: “润湿”过程 第1-10天 • 连续5个月稳定运行 • 流量超过设计值
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硼的化学特性
影响反渗透系统对硼的脱除率的因素
• pH
pH越高，硼脱除率越高
Conditions
RO2-1
110 100 90 80 70 60 50 Aug-05
Element type TDS Feed (rear) Boron Feed (rear) Temperature pH Feed Recovery % mg/L mg/L °C
BW30LE-440 >300 1.0 – 2.5 19 – 32 > 10 75-87
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3段产水量
120 normalized permeate flow (relative) (%) 100
Conditions
RO3
80 60 40 20 0 Aug-05
• 产水量大于设计产水量 • 初始阶段：泵的调整
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3段透盐率
250 Normalized salt passage (relative) (%) RO3
Conditions Element type TDS Feed Boron Feed Temperature pH Feed Recovery % mg/L mg/L °C BW30-400 25 – 120 3.0 – 6.5 19 – 32 > 10 90
• 运行初期产水量大于设计产水量 • 调整期: “润湿”过程 第1-5天 • 产水量下降(11/5)： 系统调整
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硼的化学特性
典型的硼平衡反应方程式 大多数海水淡化系统中，我们需要考虑如下方程式所给出 的化学平衡机理： pKb ~ 4.8 (with pOH) − B (OH ) 3 + H 2O ↔ B (OH ) 4 + H + 在标准条件下，大多数的海水淡化反渗透膜元件对B(OH)3 的脱除率在80-95%
世界最大海水淡化项目 按装了超过40,000支 FILMTEC 海水和苦咸水 膜元件
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项目建造者 售水价格 项目成本 项目占地面积 吨水最大耗电量 进水温度 进水含盐量 产水含盐量 脱盐率 硼去除率
IDE集团, Vivendi水务集团 Dankner-Ellem建设集团 0.527美金/吨 2.12亿美金 75,000平方米(300米 x 250米) 小于4千瓦时 16ºC - 32ºC (反渗透部分) 40,750ppm 小于40ppm 99.9% 大于92%
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高pH条件下硼的脱除率
Boron的脱除率 vs. pH
Seawater 100 Element rejection (%) 80 60 Temperature: 25C 40 20 0 5 7 9 pH 11 13 SW & BW Standard Test conditions Brackish Water Low Energy Brackish Water
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2段透盐率
160 Normalized salt passage (relative) (%) 140 120 100 80 60 40 20 0 Aug-05 40.0 35.0 Temperature (C) 30.0 25.0 20.0 15.0 10.0 5.0 0.0 Dec-05 Normalized salt passage (relative) Design salt passage @ start-up Temperature
• 温度 温度升高时，由于pkb下降，B(OH)3增多而使得硼脱除率下降 • 流量
高流量可以降低硼的透过率
• 反渗透膜片的状态
过度或长时间的清洗会造成硼脱盐率的降低
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Ashkelon 操作运营公司2006年10月宣布 投运一年以来，系统无论是产水水质还是产水量都完全达到了设计的标准。
0 Aug-05
Sep-05
Oct-05
Nov-05
Dec-05
• •
初始透盐率远小于设计值 浮动：运行条件不断在调整
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DOW RESTRICTED - For internal use only
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系统性能
标准化产水量
–2段 –3段 –4段
标准化透盐率
–2段 –3段 –4段 通过FILMTEC™ FTNORM软件 进行标准化