编者按
前两期介绍循环水蒸汽结构创新及干氯气密封，本期关注强腐蚀液体。从盐水精制到盐酸制备，衬层渗透、鼓包和脱落是常见问题。益龙以PTFE衬塑产品家族覆盖不同工段。
工况挑战
盐水、湿氯气、稀硫酸及盐酸要求材料和结构具备适配性。腐蚀性成分渗入衬层与金属之间可能积气鼓包；盐水颗粒会冲刷内件；不同浓度温度的液体需要多种阀型配合。
材料与工艺
采用PTFE和PFA衬里，原文强调其对多种酸、碱、有机溶剂的耐受性，同时将熔融碱金属及元素氟列为例外。配方优化降低孔隙率，减缓渗透。模压和烧结使衬层与金属紧密结合，避免气泡杂质，按阀型采用整体或分段衬塑以减少接缝风险。
产品家族
衬塑单座调节阀用于精确加酸加碱；衬塑隔膜阀适用于含颗粒盐水；衬塑蝶阀适合大口径低压差循环酸液。
EGSC衬塑单座阀采用PTFE波纹管及内件，铸造锚固孔加强衬里结合，扩大出口并设润滑装置；DN20–DN100，PN16/ANSI Class 150，−30°C至150°C，泄漏IV级，灰铸铁+PFA阀体，线性或等百分比特性，法兰连接。
EDVC蝶阀采用氟橡胶嵌入式密封，阀杆下轴包覆及耐蚀轴套隔离介质；DN50–DN600，PN6/10/16或ANSI Class 150；PFA为−30°C至180°C，PTFE为−30°C至150°C；泄漏IV–VI，线性特性，法兰或对夹连接。
应用实绩
原文报告在烟台万华、茌平信发华宇氧化铝及氯碱、山东海力等大型离子膜烧碱项目使用，涉及盐水精制、电解、氯氢处理和酸碱罐区，并称使用寿命、操作可靠性和维护频次得到改善。
系列结语
从水蒸汽到干氯气，再到强腐蚀液体，三期体现按工况进行材料与结构选择的思路。我们深入现场，理解需求，为用户确定适合的方案。
产品规格表
| 参数 | Lined EGSC single-seat control valve |
|---|
| 标准 | GB/T 4213-2024; HG/T 20592/20615-2009; ANSI/ASME B16.5-2009 |
| 口径 | DN20–DN100 |
| 压力等级 | PN16; ANSI Class 150 |
| 温度范围 | −30°C to 150°C |
| 泄漏等级 | IV |
| 阀体 | 灰铸铁加PFA |
| 阀芯与阀座 | PTFE |
| 流量特性 | 线性或等百分比 |
| 连接 | 法兰 |
| 附件 | Diaphragm actuator, electropneumatic/smart positioner, filter regulator |
| 参数 | EDVC lined butterfly valve |
|---|
| 标准 | GB/T 4213-2024; HG/T 20592/20615-2009; ANSI/ASME B16.5-2009 |
| 口径 | DN50–DN600 |
| 压力等级 | PN6/10/16; ANSI Class 150 |
| PFA温度范围 | −30°C to 180°C |
| PTFE温度范围 | −30°C to 150°C |
| 泄漏等级 | IV–VI |
| 阀体、蝶板与阀座 | 碳钢或不锈钢加PTFE或PFA |
| 流量特性 | 线性 |
| 连接 | 法兰或对夹 |
| 附件 | Piston cylinder, electropneumatic/smart positioner, filter regulator |
Editor’s introduction
The first two articles in this series examined structural improvements for circulating water and steam, followed by materials and sealing for dry chlorine. This final installment turns to strongly corrosive liquid service.
From brine treatment to hydrochloric-acid preparation, permeation that causes lining blisters and separation is a persistent concern. Yilong’s PTFE-lined product family is intended to address this wider range of corrosion duties.
1. Challenges in corrosive service
Chlor-alkali processes involve brine, wet chlorine, dilute sulfuric acid and hydrochloric acid. The article highlights three challenges:
- Permeation and blistering: corrosive species may penetrate a conventional fluoropolymer lining and reach the interface with the metal body. Gas accumulation can blister, deform or detach the lining.
- Wear and erosion: small amounts of solids in brine can erode internal components at high flow velocity.
- Broad application requirements: a large plant handles many corrosive fluids at different concentrations and temperatures, requiring more than one valve type.
2. Materials and lining processes
PTFE and PFA materials
Yilong selects PTFE and PFA for the lining. The article describes their broad resistance to acids, alkalis and organic solvents, while excluding molten alkali metals and elemental fluorine from that general claim. Formulation improvements are intended to lower porosity and reduce permeation that can cause blistering.
Molding and sintering
The manufacturing process aims to bond the lining closely to the metal body without bubbles or contamination. Depending on the valve construction, integral or optimized segmented lining is used to reduce leakage paths at joints.
A complete product family
- Lined single-seat control valves for accurate acid and alkali dosing.
- Lined diaphragm valves for particle-bearing brine, with smooth passages and reduced dead spaces.
- Lined butterfly valves for large-diameter, low-differential-pressure circulating-acid transfer.
3. Product specifications
The lined single-seat valve uses PTFE bellows and trim, cast lining anchors, an enlarged outlet passage and a lubrication provision to reduce stem resistance.
| Parameter | Lined EGSC single-seat control valve |
|---|
| Standards | GB/T 4213-2024; HG/T 20592/20615-2009; ANSI/ASME B16.5-2009 |
| Nominal size | DN20–DN100 |
| Pressure rating | PN16; ANSI Class 150 |
| Temperature range | −30°C to 150°C |
| Leakage class | IV |
| Body | Grey cast iron with PFA |
| Plug and seat | PTFE |
| Flow characteristic | Linear or equal percentage |
| Connection | Flanged |
| Accessories | Diaphragm actuator, electropneumatic/smart positioner, filter regulator |
The lined butterfly valve uses an embedded fluororubber seal, lining around the lower shaft and stem, a corrosion-resistant bushing and a PTFE stem seal. Direct actuator connection removes the need for a separate gland flange.
| Parameter | EDVC lined butterfly valve |
|---|
| Standards | GB/T 4213-2024; HG/T 20592/20615-2009; ANSI/ASME B16.5-2009 |
| Nominal size | DN50–DN600 |
| Pressure rating | PN6/10/16; ANSI Class 150 |
| PFA temperature range | −30°C to 180°C |
| PTFE temperature range | −30°C to 150°C |
| Leakage class | IV–VI |
| Body, disc and seat | Carbon steel or stainless steel with PTFE or PFA |
| Flow characteristic | Linear |
| Connections | Flanged or wafer |
| Accessories | Piston cylinder, electropneumatic/smart positioner, filter regulator |
4. Reported applications
The article reports use in several large membrane-cell caustic-soda projects, including:
- Yantai Wanhua Chemical Group.
- Chiping Xinfa Huayu alumina/chlor-alkali operations.
- Shandong Haili Chemical.
- Other large chlor-alkali manufacturers.
It describes applications in brine purification, electrolysis, chlorine/hydrogen handling and acid/alkali storage areas. Reported customer feedback includes longer valve life, dependable operation and less frequent replacement and maintenance.
5. Completing the series
The three articles cover water and steam, dry chlorine, and strongly corrosive liquids. Together they present Yilong’s approach to application-based solutions across the chlor-alkali process. Our aim is to understand the plant’s actual operating conditions and develop an appropriate configuration with the user.
