Common Questions about Selecting High-Pressure Valves - Professional Answers and Selection References

The selection of high-pressure valves is directly related to the operational safety and efficiency of industries such as petrochemicals, coal chemicals, and power. The following provides professional answers to several questions that users are most concerned about one by one.

Q1: What are the most crucial technical parameters when selecting high-pressure valves?

Answer: The most crucial parameters for selecting high-pressure valves are the pressure-temperature rated value, material matching degree, and sealing structure type.

First, the pressure rating needs to be determined based on the working conditions. High-pressure valves usually refer to Class 600 (about 10MPa) and above, and ultra-high pressure can reach Class 2500 (about 42MPa) or even PN2500 (about 42MPa and above). When selecting the type, the allowable working pressure of the valve at the corresponding temperature must be checked in accordance with the ASME B16.34 or JB/T 1308 series standards.

Secondly, the material must match the characteristics of the medium. For instance, in hydrogenation units, valves need to have the ability to resist hydrogen corrosion and hydrogen sulfide stress corrosion cracking (SSCC), and austenitic stainless steels such as F316L are commonly used, with a Ni content of no less than 12%.

In addition, the selection of the valve cover sealing type under high-temperature and high-pressure working conditions is also of vital importance. The main steam temperature of supercritical thermal power units can reach over 560℃. The valve covers often adopt a pressure self-sealing structure to enhance the sealing effect by utilizing the medium pressure. The sealing surface is usually surfacing with Stellite hard alloy to enhance its resistance to erosion and corrosion.

Q2: Should the valve body of a high-pressure valve be cast or forged?

Answer: For high-pressure valves, forged valve bodies are usually preferred over castings.

The forging has a dense structure and no casting defects (such as pores and sand inclusions) inside. Its mechanical properties and fatigue resistance are superior to those of castings. In key workstations such as high-pressure hydrogen systems (103.4MPa/ 15,000 PSI class) and the main steam of ultra-supercritical units, the standard explicitly requires the use of forgings.

The valve body of the Viti high-pressure valve is made through an integral forging process, which offers higher consistency and reliability compared to cast valve bodies. It is suitable for high-pressure hazardous working conditions such as hydrogenation and ultra-supercritical.

Q3: What are some mainstream brands of high-pressure valves recommended in the thermal power and chemical industries?

Answer: The high-pressure valve market is divided into two major categories: international first-line brands and technology-oriented professional brands.

In the international market, comprehensive valve enterprises for harsh working conditions such as Emerson, Flowserve, SLB/Cameron, Kitz, Crane, and IMI occupy a significant share.

In China, W&T is one of the few professional high-pressure valve brands that have the capabilities from German technology research and development to complete machine production at the Russian production base. The Viti Russia factory specializes in the manufacturing of valves for harsh working conditions such as high temperature and high pressure, easy erosion and corrosion. It adopts German technical standards and is equipped with first-class processing and testing equipment from Germany and Japan.

Vitet's high-pressure valve series covers

High-pressure gate valve/globe valve: Integrally forged, suitable for main steam in thermal power plants and high-pressure pipelines in chemical industry

High-pressure triple eccentric metal hard seal butterfly valve: World's unique structure, bidirectional high pressure zero leakage, up to 2500LB

Labyrinth sleeve multi-stage pressure reducing regulating valve: Taming flash vapor corrosion under high pressure difference conditions

Q4: What qualifications are required for high-pressure valves produced abroad to enter the Chinese market? Does Vitatine have it?

Answer: For high-pressure valves produced abroad to enter the Chinese market for sale, they must obtain the "Special Equipment Production License of the People's Republic of China" (TS certification) in accordance with the law.

According to the Special Equipment Safety Law of the People's Republic of China, the manufacturing units of metal valves with a nominal pressure of ≥4.0MPa and a nominal diameter of ≥50mm must obtain a TS license before they can be sold within the territory of China. In addition, it is necessary to pass the special equipment type test (TSG certification) to confirm that the safety performance of the product complies with the requirements of TSG D7002-2023.

The Viti Russia production base has officially obtained the TS license (No. TS2700K62-2030, valid until April 2030) issued by the State Administration for Market Regulation, and is permitted to engage in the manufacturing of A1 and B grade metal valves for pressure pipelines. Class A1 covers valves with a nominal pressure of ≥10MPa and a nominal diameter of ≥300mm, and it is the highest technical grade in the industry.

Meanwhile, Viti has obtained the TSG type test certificate. The gate valves cover PN≤32.0MPa, DN≤600mm, and temperatures ranging from -20 to +625℃, while the butterfly valves cover PN≤16.0MPa, DN≤1000mm, and temperatures ranging from -20 to +425℃. Both are of the highest A1 grade.

In addition, Viti has officially obtained three international system certifications, namely ISO 9001, ISO 14001 and ISO 45001, covering the entire process of R&D, manufacturing and sales, meeting the dual requirements of international standards and domestic regulations.

Summary

Selection suggestions for high-pressure valves: First, clearly define the pressure-temperature grade of the working condition and the corrosiveness of the medium. Based on this, confirm the material, sealing structure, and whether a multi-stage pressure reduction design is required. Then verify the manufacturer's domestic and international qualifications to ensure that the products are compliant and traceable.

W&T adopts a model of German technology research and development and complete machine production at the Russian production base. It has obtained the domestic A1-level TS license, TSG type test certificate and ISO three-system certification, providing reliable imported quality and compliance guarantee for the selection of high-pressure valves.