本文分享氯碱行业进口阀门选型经验，涉及山东海力、滨化、万华等项目。一次二次盐水、离子膜电解槽出口氢氯气调节、氯压缩、烧碱蒸发及盐酸制备，各有不同要求。
工艺概览
原盐溶解后经过一次、二次盐水精制及离子膜电解，产出碱液、氢气与氯气。碱液浓缩进入液碱或固碱后续流程；氢氯处理可进入氯化氢合成、盐酸生产及有关下游工序。
一、盐水精制
流量大、腐蚀强，调节精度通常不如电解槽出口要求严格。可选衬塑蝶阀、旋塞、球阀和隔膜阀，原文推荐XOMOX和Saunders，均属CRANE集团。PFA衬里致密性和耐氯离子渗透能力是选型重点。原图比较PTFE放大2000倍与PFA放大10000倍的微观结构，并强调外漏控制。应用列举山东海力、滨化、山东金岭和烟台万华。
二、电解槽出口
为维持膜两侧压力平衡，需要高精度调节。氢气应用采用SCPH2阀体及316内件，原文推荐MOTOYAMA 3889，介绍其与旭化成及北化机设备的供货经验。湿氯气酸性强，推荐特材波纹管单座阀及HC波纹管密封，原图展示3889内部与波纹管结构。
三、氯气压缩
原文限定干氯气含水低于50 ppm，所述MOTOYAMA方案采用3889波纹管单座阀，SCPH2阀体、316内件及波纹管，并称不含Ti的316材料有利于该工况抗点蚀。顶部六角导向减少波纹管脆裂。文章介绍本山自1928年从事波纹管制造，并报告齐鲁石化氯碱厂1988年安装的阀门在原文撰写时仍保持良好运行。
四、烧碱蒸发精制
回流碱液需限制铁离子污染，原文推荐2916特材蝶阀，SCS18阀体、HC内件。非回流碱液则推荐304阀体、316内件的3889单座调节阀。
五、盐酸制备
腐蚀强、温度一般不高，精确调节推荐Kammer 132000衬塑单座阀；精度要求较低时可选XOMOX衬塑产品。
切断阀
腐蚀工况采用XOMOX衬塑蝶阀、旋塞、球阀或Saunders隔膜阀；非腐蚀工况根据需求选用常规蝶阀或球阀。
山东龙飞机电设备有限公司在离子膜烧碱项目积累十余年经验，希望通过现场应用经验，为用户提供选型支持，共同合作发展。
To our colleagues working on chlor-alkali production lines: this article shares practical experience in selecting imported valves. Projects at Shandong Haili, Befar and Wanhua have provided useful lessons on matching products to critical duties.
Different process stages place different demands on control valves. The principal applications discussed here are primary and secondary brine purification, hydrogen and chlorine control at membrane-cell outlets, chlorine compression, caustic-soda evaporation and purification, and hydrochloric-acid preparation.
Process overview
Raw salt is dissolved and passes through primary and secondary brine purification before membrane electrolysis. The process produces caustic liquor, hydrogen and chlorine. Caustic concentration leads to downstream liquid or solid products; hydrogen and chlorine treatment also feed hydrogen-chloride synthesis, hydrochloric-acid production and related downstream processes.
1. Primary and secondary brine purification
These stages involve high flow rates and strong corrosion, while the required regulating precision may be less demanding than at the electrolyzer outlets. Suitable types include lined butterfly, plug and ball valves and diaphragm valves.
The article recommends XOMOX lined butterfly, plug and ball valves and Saunders diaphragm valves. Both brands are part of the CRANE group. It describes XOMOX as an early developer of fluoropolymer-lined valves and Saunders as a pioneer of the diaphragm valve.
The source highlights PFA linings for density and resistance to chloride penetration. Its micrograph compares PTFE at 2,000× magnification with PFA at 10,000×, illustrating the denser appearance of the PFA sample. It also emphasizes external-leakage control.
Applications cited include membrane-cell projects at Shandong Haili Chemical, Befar Group, Shandong Jinling and Yantai Wanhua chlor-alkali operations.
2. Hydrogen and chlorine at the electrolyzer outlet
Accurate control is required to maintain the pressure balance across the membrane. Hydrogen and chlorine duties require different material and sealing arrangements.
Hydrogen
The article specifies an SCPH2 body and 316 stainless-steel trim. It cites the MOTOYAMA 3889 single-seat valve and the manufacturer’s supply history with Asahi Kasei and equipment packages from Beijing Chemical Machinery. The source reports broad use in Chinese membrane-cell plants and favorable accuracy and service-life experience.
Wet chlorine
The wet chlorine leaving the electrolyzer is strongly acidic. The article specifies a special-material, bellows-sealed single-seat valve, citing the MOTOYAMA 3889 with an HC-alloy bellows seal for long service life and precise control. The original illustrations show the 3889’s internal construction and bellows arrangement.
3. Chlorine compression
The article describes dried chlorine with moisture below 50 ppm. For this stated duty, its MOTOYAMA configuration is a 3889 bellows-sealed single-seat valve with an SCPH2 body and 316 trim and bellows. The source states that the manufacturer’s 316 material contains no titanium and associates this selection with resistance to pitting in the specified service.
Top hexagonal guidance is intended to reduce brittle bellows failure. The article notes MOTOYAMA’s history in bellows manufacture from 1928 and reports that valves installed at Qilu Petrochemical’s chlor-alkali plant in 1988 had remained in service without failure when the source article was written.
4. Caustic-soda evaporation and purification
The medium is mainly sodium hydroxide, with different requirements for recycled and non-recycled caustic liquor.
- Recycled caustic: where iron-ion contamination must be avoided, the article recommends a special-material butterfly valve, principally the MOTOYAMA 2916 with an SCS18 body and HC trim.
- Non-recycled caustic: the article identifies the MOTOYAMA 3889 single-seat valve with a 304 body and 316 trim as an option.
5. Hydrochloric-acid preparation
The principal issue is strong corrosion, generally at relatively modest temperatures. Where high regulating accuracy is required, the source recommends the Kammer 132000 lined single-seat valve. Where accuracy is less demanding, XOMOX lined products are suggested.
Shut-off valves
For corrosive isolation duties, the article recommends lined butterfly, plug and ball valves or diaphragm valves, including XOMOX and Saunders products. For non-corrosive duties, it identifies conventional XOMOX butterfly and ball valves as suitable options according to the service requirements.
Application support
Shandong Longfei Electromechanical Equipment Co., Ltd. describes more than a decade of valve-application experience in membrane-cell caustic-soda projects. We offer this experience to help customers review their operating conditions and select appropriate configurations, and welcome cooperation on future projects.
