China's petrochemical industry control valve demand technology outlook

Abstract: The petrochemical industry is called petrochemical for short. It plays an important role in the development of China's national economy and is one of China's pillar industries. The petrochemical industry has a long production line and involves a wide range of fields. In the petrochemical industry, the control valve is one of the most important devices. The quality of the control valve is directly related to the operation of the DCS control system and the operation of the process device, once the control valve fails. The entire control system will fail.

The petrochemical industry is called petrochemical for short. It plays an important role in the development of China's national economy and is one of China's pillar industries. The petrochemical industry has a long production line and covers a wide range of areas. Only Sinopec Group has nearly 6,000km of crude oil, refined oil, natural gas and other oil transmission and gas pipelines, 24,000 gas stations, petrochemical companies' oilfields, oil production plants, oil refineries, and chemical plants. Depots, oil depots, gas stations, and oil (gas) pipelines cover all cities, townships, railway stations, terminals, hotels, and households throughout the country. The petrochemical industry's production processes include oil and gas exploration, oil and gas field development, drilling engineering, oil production engineering, oil and gas gathering and transportation, crude oil storage and transportation, petroleum refining, chemical production, and sales of oil products, and production of gasoline, kerosene, diesel oil and lubricants needed by society. More than 3,000 petroleum and chemical products such as chemical raw materials, synthetic resins, synthetic rubber, synthetic fibers, and chemical fertilizers are closely related to people's clothing, food, housing, and transportation.

In the petrochemical industry, the control valve is one of the most important devices. The quality of the control valve is directly related to the operation of the DCS control system and the operation of the process device. Once the control valve fails, the entire control system will fail. The petrochemical industry has a large variety of control valves in China, and the structure and material selection of different valves vary greatly, and the needs of users vary widely. This issue of the magazine specifically interviewed Mr. Yu Xubo, Senior Engineer of the Instrument Control Room of Sinopec Shanghai Engineering Co., Ltd., and conducted an exclusive interview on the status and prospects of the demand for control valves in the petrochemical industry. Yu Xubo's engineers have been deeply involved in the petrochemical field for a long time. He is familiar with the status of the control valve in the front line. He combines the facts and points out many problems of the domestic control valve products, and puts forward many valuable opinions to the domestic control valve manufacturers in order to guide the order of the domestic control valve industry. High-speed further development.

For the special conditions, overall, the current domestic control valve problem lies in the application of high temperature and high pressure conditions, the main problem is that the maintenance cycle is short, especially when the material contains particles, it is difficult to deal with, which is forcing Users have to directly introduce foreign products in some key applications. In high temperature conditions, structural design, finishing and assembly are particularly important, and the technical level of domestically produced control valves is not mature enough in this respect. The application of low temperature conditions, the domestic control valve is basically able to deal with. In general, the quality of domestic single-seat valves is relatively stable and the market share is also high. It is worth noting that the domestic butterfly valve has made rapid progress in recent years.

In our petrochemical industry, most designers use American Standards when selecting control valves, or adopt domestic standards equivalent to American Standards, which cover material, inspection, and test standards.

In general, more than 75% of the operating conditions in the petrochemical industry are not very harsh, but there are also many special conditions, such as large-diameter and micro-flow valves. Judging from the application of products at this stage, large-diameter valves are not a problem. Many domestic valves are doing well. On the contrary, micro-flow valves are a problem. On the one hand, the application of these valves is relatively small, not very attention; on the other hand, their spools are very small and very easy to wear, such as high pressure differential injection valve, the domestic manufacturers in this area is still very little research This led to the blankness and backwardness of the product in this area.

From the perspective of our actual project and project status, there are many situations in which the user specifies the supplier of the source. Sometimes the solution we provide for the user must be carried out in the case of the brand and specified type specified by the patent operator. The control valve manufacturer should This caused attention.

The length of life of a control valve, first look at the application conditions, and then see the control valve material and sealing performance.

For sealing, it is divided into seat seal and packing seal. We know that the control valve emphasizes the continuous control function and does not require strict close-off function. Therefore, even if there is a certain leakage, the valve seat seal is not paid much attention; and depending on the operating conditions and the structure of the control valve, for example, Ball valve, valve seat sealing grade is very high, as a very close function is very appropriate.

We know that if there is a leak in the valve seat seal, at least the fluid is still in the pipe, and the packing seal will cause problems. The chemical medium may be directly discharged into the environment and the consequences will be unimaginable. With the improvement of the environmental protection requirements of the country, the engineering design nowadays is paying more and more attention to packing seals. As an engineering designer, we are also looking forward to the upgrading of domestically-made control valve packing seals, which in the final analysis will be material and manufacturing standards. If according to the requirement of low leakage, the index of the home-made packing does not pass; In addition, some processing links, such as the smoothness of the valve stem, are related to the leakage amount. According to our understanding, European countries and the United States have long launched a series of products that they call environmental protection fillers to meet the environmental requirements of the local government. In recent years, domestically-made control valves have gradually begun to use double-layer packing to achieve low leakage. For example, Wuxi tooling, they have been able to provide double-layer packing products, and have been used in European and American joint ventures. I hope that more domestic control valve companies can pay attention to this issue.

Regarding the material issue, it is also a difficult problem that our petrochemical industry control valve products need to deal with. The petrochemical industry has a wide variety of working conditions and fluids, and the choice of valve material is of utmost importance. The selection of suitable materials will ensure the longevity of the control valve. The domestic control valve factory should conduct in-depth research, especially for the improvement of the material, and it should be studied.

There are two suggestions for how to prolong the life of the control valve:

First, control valve manufacturers should increase research and development efforts and work hard on the valve core components. The response of customers is that the valve life of domestically produced control valves is short. This is of course related to the process operating conditions, but it should also be related to the manufacture of control valves. We try to use the appropriate structure of the valve core, also hope that the domestic control valve manufacturers in the manufacturing process to improve stability, which is an engineering system, involving materials, processing, assembly, inspection.

Second, make a fuss about the soft seal seat. The soft seal life of the domestic control valve is short, causing users to choose the metal seal control valve. In fact, in Europe, soft-seal valve seat control valve accounts for a certain percentage, in the case of compliance with the process, soft seat valve control valve can reduce most of the investment, and life is also guaranteed. In terms of non-metal materials, there is a big gap between domestic products and foreign countries. Take the taps in our lives, this is a simple valve, and the sealing sheet is generally made of rubber, and its service life is not long. This kind of thinking also affects the valves in the industrial sector.

In the petrochemical industry, the selection of control valves can be appropriate. In general, there is no need to exceed the design of the valve for normal conditions. If it is a severe working condition and the introduction of a regulating valve is used, it is recommended to add inspection steps and test reports.

The so-called safety and operability requirements are all based on proper selection and use. For different working conditions, analyze the valve from the perspective of its structure, material, type, and restriction conditions. Of course, correct operation and proper maintenance are also important factors.

Domestically produced control valves have improved a lot in terms of conventional and low temperature, and they perform well, but strictly speaking, there is still a product to be improved in the domestically produced control valve field. That is the positioner. Now all of them are familiar with foreign brands. The stability and repeatability of domestically-made locators are different from theirs. In actual use, they also purchase locators from imported brands.

Secondly, there is a gap between domestic precision machining and assembly technology, and the same assembly is processed and assembled in China. The quality is always discounted. Even some of the imported brands have repeatedly encountered such problems. The root cause is that the quality system cannot Maintain long-term stability.

We should strive to catch up with foreign products and increase research and development efforts.

It should be said that the quality of imported brand control valves is generally excellent. Of course, they are expensive and have long delivery times. Due to geographical constraints and certain weaknesses of multinational corporations, imported brand control valves are generally not satisfactory in after-sales service; in the impression of many users, the sales of big brand products are always slow or do not get very good. Good after-sales service,

On the contrary, domestically produced control valve products have done a good job overall. Whether it is the follow-up of after-sales services, or the timely replacement of spare parts, on-site adjustments and improvements, etc., in these respects, domestically produced control valve manufacturers have considered very comprehensively. The user is very caring.

We believe that in addition to the need to introduce foreign control valves in particularly critical operating conditions, most other companies prefer control valves for domestic or joint ventures. This reduces procurement costs, guarantees delivery time, and ensures on-site service.

There are two points about the development trend:

Firstly, in the current international control valve market, the dominant products are spherical single-seat valve, sleeve valve, adjusting butterfly valve and cam flexure valve. In our country, the first three types have dominated the control valve market. Half of the country, but the only cam deflection valve has not been widely used, why not get a good promotion of good things?

In fact, cam deflection valve structure, control performance is not bad, the relative flow capacity, in the 4 inch diameter above the price advantage, such as MASONEILAN, FISHER, FLOWSERVE these brands are in the production of cam deflection valve, the application in foreign countries is indeed very However, it is regrettable that it cannot be promoted in China. Ten years ago we talked about the prospects of cam deflection valves. In principle, its spool is relatively thick and resistant to wear. It may be a trend for future development. However, it has not been promoted in practical applications. Users do not accept it, there are not many manufacturers. The reason is that at that time, domestic awareness of rotary valves was not enough. No one was willing to spend time investing in R&D. There were too few manufacturers producing rotary valves and the market share was of course low. Now domestic butterfly valve products have made rapid progress. It should be said that the cam deflection valve is still promising.

The second is the sluice valve. The structure of the valve is very simple. Two sliding plates perpendicular to the flow direction of the medium are installed in the valve body. One slide plate is fixed inside the valve body, and throttling with the same width and different lengths is opened on the plate. The slot, the other is just a movable slide connected to the valve stem, it is close to the fixed slide, also has a throttle slot on it. Moving the skateboard can change the size of the media flow area to control the flow of the media. This kind of valve structure is very suitable for clean gas working conditions, and the maintenance volume is small, which is worthy of wide application.