The petrochemical industry plays a vital role in the national economy, and chemical process pumps, as essential auxiliary equipment, are increasingly attracting attention. Due to the complexity of chemical media and the growing demands from users, manufacturers must make informed choices. What factors should be considered? These questions are crucial. Based on the company's product features and my understanding of chemical pump selection, I would like to share some insights to help colleagues in this field perform their tasks more effectively.
Corrosion resistance is one of the most critical concerns in chemical equipment. A single oversight can lead to equipment damage or even serious accidents. According to statistics, about 60% of chemical equipment failures are caused by corrosion. Therefore, selecting the right materials for chemical pumps is essential. There is a common misconception that stainless steel is a "universal material" suitable for all environments, which is dangerous. Below are some key considerations for selecting pumps based on different chemical media:
1. **Sulfuric Acid**: As a highly corrosive medium, sulfuric acid requires careful material selection. For concentrated sulfuric acid (over 80% concentration) at temperatures below 80°C, carbon steel and cast iron offer good corrosion resistance. However, they are not suitable for high-speed flow. Common stainless steels like 304 and 316 have limited use. High-silicon cast iron and high-alloy stainless steels (e.g., 20 alloy) are often used for pump valves. Fluoroplastic pumps, such as F46-lined pumps, are cost-effective options. Our products include IHF lining pumps, PF (FS) corrosion-resistant centrifugal pumps, and CQB-F fluoroplastic magnetic pumps.
2. **Hydrochloric Acid**: Most metals, including stainless steel, are not resistant to hydrochloric acid. Non-metallic materials like rubber and plastic (e.g., polypropylene, fluoroplastics) are better choices. Our product range includes IHF fluorine-lined pumps, PF (FS) strong corrosion-resistant pumps, and CQ polypropylene or fluoroplastic magnetic pumps.
3. **Nitric Acid**: Most metals are corroded by nitric acid. Stainless steel is widely used, but molybdenum-containing grades like 316 may not perform better than standard stainless steels. For high-temperature nitric acid, titanium and titanium alloys are preferred. Our products include DFL (W) H, DFL (W) PH shielded pumps, DFCZ process pumps, and others.
4. **Acetic Acid**: One of the most corrosive organic acids, acetic acid can severely corrode ordinary steel. Stainless steel is an excellent choice, especially 316 with molybdenum for high-temperature dilute solutions. For high-concentration or harsh conditions, high-alloy stainless steels or fluoroplastic pumps are recommended.
5. **Alkali (Sodium Hydroxide)**: Steel is commonly used for sodium hydroxide solutions below 80°C and 30% concentration. At higher temperatures, titanium or high-alloy stainless steel is preferred. Our company offers cast iron pumps for low-temperature, low-concentration applications, and stainless steel or fluoroplastic pumps for special requirements.
6. **Ammonia (Ammonia Hydroxide)**: Most metals and non-metals show minimal corrosion in ammonia solutions. Copper and its alloys should be avoided. Our pumps are suitable for ammonia transportation.
7. **Saline (Seawater)**: Ordinary steel corrodes quickly in seawater. Painting or using 316 stainless steel is common. Many companies use 316 pumps for such applications.
8. **Alcohols, Ketones, Esters, Ethers**: These media are generally non-corrosive, and common materials can be used. However, care should be taken with sealing materials, as some rubbers may dissolve in these substances.
There are many other media not covered here. In short, material selection should not be arbitrary—consulting information or learning from experience is essential.
**Cooling Issues**: High-temperature media require special cooling systems. For media below 120°C, most pumps rely on self-cooling. For temperatures above 120°C up to 300°C, cooling chambers and double mechanical seals are necessary. For temperatures over 300°C, advanced cooling systems and metal bellows seals are required. Our company offers various high-temperature pumps, including DFCZ, GRG, HPK, and CQB-G models.
**Sealing Problems**: Leak-free operation is the goal of chemical equipment. Magnetic and shielded pumps are popular, but challenges remain regarding lifespan, material pitting, and static seal reliability. Static seals typically use O-rings, while dynamic seals mainly use mechanical seals, with double-end seals for high-temperature or viscous media.
**Viscosity Issues**: Viscosity significantly affects pump performance. Higher viscosity reduces head and flow while increasing power consumption. Pulp and paste-like liquids may require screw pumps. Our DFGG single-screw pump can handle media with viscosity up to 1,000,000 cSt.
In conclusion, selecting the right pump involves understanding both the media and the application environment. Careful consideration of material, cooling, sealing, and viscosity ensures optimal performance and safety.
Low Temperature Battery Additive,Lithium Bis(fluorosulfonyl)imide,Lithium Trifluoromethanesulfonate,Lithium Salt Additives
Suzhou Cheerchem Advanced Material Co., Ltd. , https://www.szcheerchem.com