General requirements and special requirements of valves in petrochemical plants and advantages of API valves

Our North Valve Group Co., Ltd. is a manufacturer of research and development, production and sales of standard general industrial valves such as high-pressure valves, ball valves, gate valves, butterfly valves and globe valves, with diameters ranging from 10mm to 3000mm and nominal pressure PN ranging from 1Mpa to 80Mpa. At the same time, we can also customize non-standard valves for you. Welcome to call us.

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General requirements for valves in petrochemical plants

1. Internal leakage problem

The amount of internal leakage is the main technical index to measure the quality of a high-pressure gate valve. Q In the general petrochemical production process, flammable, flammable, explosive and toxic media are handled. When the high-pressure gate valve is closed, it is hoped that the leakage through the gate (that is, internal leakage) will be as little as possible, and even some media will be involved.

The leakage requirement of quality is zero. The commonly used standards for judging the internal leakage of high-pressure gate valves are AP1598, ANSIB 16.104 X ZBJ 16006 and JB/T 9092-99. The requirements of the standard for high-pressure gate valves before leaving the factory are as follows: shell pressure test and sealing test are carried out before leaving the factory. Sealing test includes upper sealing, low-pressure sealing and high-pressure sealing test. Only high-pressure gate valves with upper sealing structure, such as gate valves and globe valves, are subjected to upper sealing C shell pressure test. Generally, water with a temperature not exceeding 52℃ or non-corrosive fluid with a viscosity not greater than water is used at a nominal pressure of L 5 times at 38 C.. Low pressure sealing test, generally using air or gas, with 0.5-0. 7\IPa pressure. The high-pressure sealing test is carried out with air or inert gas as the medium and the pressure is L1 times the nominal pressure.

2. Leakage problem

External leakage refers to the external leakage of medium through the valve stem packing and bonnet gasket, which is also an important index to measure the quality of high-pressure gate valve. For some media, the requirement of external leakage is even stricter than that of internal leakage, because it directly leaks into the atmosphere; It will directly cause accidents or personal injuries. C In this case, bellows sealing valves and diaphragm valves are sometimes used to ensure that the leakage of high-pressure gate valves is zero. At present, most of the standards for limiting leakage are limited by the US Environmental Protection Agency, that is, no more than 500PPm. Low Emissions test standard, using chlorine as the test.

3, material quality

Material quality is an important index to measure the strength, reliability and service life of high-pressure gate valves. As we know, most of DNN50 high-pressure gate valves are cast valve bodies. If the casting quality is not good, it will directly affect the reliability and service life of high-pressure gate valves. C In general, the requirements of China's material standards are relatively low. In order to ensure that materials can better meet the requirements of operation under harsh conditions, many optional additional inspection items have been added to these standards. How designers choose these additional items according to the use conditions is a highly technical problem, and improper requirements will increase infrastructure investment meaningless.

X43F46\PO fluorine-lined plug valve

Special requirements for valves in petrochemical plants

1. Ball valves, plug valves and other special high-pressure gate valves with general structure used for process materials, extremely and highly hazardous media and combustible media pipelines should have fireproof and antistatic structures. The manufacturer shall have the testing means conforming to API 607.

2. For the high-pressure gate valve with soft seal, the pressure and temperature parameters of the seal shall meet the requirements of pipeline design conditions.

3. For high-pressure gate valves (except check valves) in cryogenic systems, the extended bonnet structure should be selected.

4. For the elastic gate valve of cryogenic system, an exhaust hole should be opened on the valve disc on the high pressure side.

5. The high-pressure gate valve with threaded bonnet should not be used for extremely and highly hazardous media and liquefied combustion pipelines.

High pressure ball valves Q41N, Q61N, Q11N

Advantages of API valve

Since the beginning of 1990s, domestic API high-pressure gate valves have been widely used in China's petrochemical industry. Manufacturers producing API high-pressure gate valves are also generally blooming; There are dozens of manufacturers that have obtained API certification. Practice has proved that high-pressure gate valves have many advantages compared with high-pressure butterfly valves. Therefore, China also introduced GB high-pressure gate valve equivalent to high-pressure gate valve in the early 1990s.

However, it has not been popularized for various reasons. Therefore, at present, high-pressure gate valves are generally used in the pipelines of large external economic series.

Generally speaking, compared with the high-pressure butterfly valve, the high-pressure gate valve has the following advantages:

A, the structural design is reasonable. The main performance is that the DN250 high-pressure gate valve adopts elastic gate (for gate valve), which can automatically adjust its fit with the sealing surface of the valve seat, thus reducing internal leakage;

B, the standard is relatively complete and complete;

C, there is a special quality and product certification body.

After reading this article "General Requirements, Special Requirements and Advantages of API Valves for Petrochemical Devices", I believe you have a certain understanding of high-pressure valves. Our North Valve Group Co., Ltd. is a manufacturer of high-pressure valves. For decades, the company has sold high-quality valve products, and the product technology and quality have been certified by national authorities, reaching national standards and deeply trusted by customers.

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