Abstract: In the chemical engineering, the valve occupies an important position and is an important guarantee for the smooth and safe development of chemical production. The selection of the valve is the content that chemical engineering design should pay attention to. This article analyzes the commonly used valve selection strategies in chemical design and hopes to provide some help for the development of the chemical industry.
Keywords: chemical design; commonly used valves; selection strategy In chemical production, the types of valves are various and play different roles, including control, isolation, and prevention of backflow, and are important components for controlling chemical production efficiency and progress. Production safety also plays a role that cannot be ignored. In the current market, the types of valves are various. If you choose to make mistakes, it will seriously affect the smooth development of chemical production, or even cause serious safety incidents. Therefore, it is an important part of chemical design to master reasonable and commonly used valve selection strategies. jobs.
1 Basic points of valve selection in chemical engineering design In chemical engineering design, in order to ensure the rationality and reliability of valve selection, the following basic points must be mastered:
First of all, it is necessary to clarify the specific use of the valve. There are tens of thousands of types of valves, and there are differences in the performance and applicable conditions of different valves. When selecting a type, it is necessary to understand the pressure, control methods, etc. of the pipeline first, and to clarify the specific requirements of the valve function and parameter indicators in order to make Targeted selection, improve the selection of reasonable; Second, select the appropriate type. In a wide variety of valves, there are significant differences in the production process and performance. In the selection process, it is necessary to first grasp the type of valve, select the appropriate valve from the same type of function, and prohibit the use of mixed valves. , determine the valve port. The valve is connected with the pipeline to constitute the chemical production system. The valve connection port is an important factor affecting its application safety. Therefore, it is necessary to pay more attention to the valve port and do a good job of selection control. Fourth, do a good job of valve quality control. Valve manufacturing materials, processes, etc. will affect the quality of the valve, in the current market, the quality of the valve varies, in the selection, the need to do a good job of valve quality testing, strict quality control, can improve the reliability of the use of the valve.
2 Specific strategies for valve selection in chemical engineering design In chemical engineering, the commonly used types of valves include gate valves, butterfly valves, ball valves, throttle valves, globe valves, and plug valves. Valve performance, characteristics, operating parameters, and applicable conditions The other aspects are the key points to be considered in the selection process. The specific selection strategy is:
2.1 Valve selection strategy In the current valve market, the gate valve occupies a considerable proportion, the basic principle is to drive the valve plate through the valve stem, to achieve the control of the lifting movement, with a light switch, good elastic memory, good airtightness , Switching operation flexibility and outstanding adjustment performance, but there are structural deficiencies, maintenance difficulties. According to the characteristics of the gate valve, in the chemical design, the gate valve has a wide range of applications, including solid particle media, steam and oil products in the chemical production, has a good effect on the use of vacuum systems, exhaust valves. In addition, in the selection of the gate valve in the production of solid particulate media, it is necessary to cooperate with the blowhole to prevent the gate valve from being blocked by particles. When the medium temperature is low, a special low-temperature gate valve needs to be selected to avoid affecting the normal use of the gate valve.
2.2 The strategy of butterfly valve selection In chemical engineering design, when the pipeline size of the project is large and the structure size is short, the butterfly valve is suitable for the rapid opening and closing of the pipeline, and the control capacity of the pipeline flow is strengthened. Air media compression and oil aspects. In the operating range of 1KPa and 80°C, the pressure loss of the butterfly valve will exceed the gate valve. Therefore, the selection of the butterfly valve also needs to take into account the pipeline pressure factor. When the pressure requirement is relatively low, the butterfly valve may be used. The gate valve has a high degree of safety.
2.3 Ball valve selection strategy Ball valve has many advantages, including good wear resistance, good sealing and long service life, has wide applicability to the medium, viscosity, low temperature, high pressure and corrosive media, can be used Ball valve is the most widely used valve in chemical design. However, in the selection of the ball valve, it is necessary to take into account the problem of the diameter. When the diameter of the ball valve is large, it is necessary to assist the turbine transmission device to complete the opening and closing of the ball valve with external force, thereby ensuring the play of the ball valve.
2.4 The strategy of globe valve selection The globe valve has a good adaptability to the operating environment, and has good ability to adjust the pressure and temperature. It can be used in high pressure and high temperature medium pipelines, but the adjustment accuracy is low and the fluid resistance is certain. The requirements apply only to pipelines with low fluid resistance values ​​and do not apply to conditions where the viscosity is high or the medium particles precipitate more. Generally speaking, the cut-off valve can be selected in the pipe with small diameter, low adjustment performance requirements or steam pipeline with DN below 200mm. In addition, when the pipeline medium is liquid or toxic gas, it is also necessary to select the cut-off valve and use the cut-off valve. Good sealing performance to prevent the leakage of liquid or toxic gas and improve the safety of chemical design. Finally, the globe gasket replacement is very convenient. In the installation operation, only the direction of the valve and the direction of the fluid can be unified, the construction is simple, and it is widely used in chemical engineering design.
2.5 Throttle valve selection strategy Throttle valve plays a significant role in energy conservation in chemical production. In the selection of throttle valve, the applicable conditions are the smaller diameter and low regulation performance of the pipeline. Compared with the cut-off valve, the two are similar in structure, but the throttling valve has more throttling components, which has obvious advantages in energy saving and is in line with the requirements of modern sustainable development. The disadvantages are mainly reflected in the low control precision and the requirement. Relatively strict piping does not apply.
2.6 Plug Valve Selection Strategy The characteristics of the plug valve are mainly the fast opening and closing speed. It is applicable to the pipeline with high requirements for start-stop, but in the media, high-temperature medium is not applicable. Suspended particles and high-viscosity media It has good applicability. In the actual chemical design, this kind of complex medium requirement restricts the use of the plug valve to a certain extent, and needs to be selected according to its applicable conditions.
3 Conclusion In summary, in the chemical design, the valve selection is very critical, will directly affect the design quality, strengthen the study of the selection of commonly used valves, master the correct selection strategy, to improve the level of chemical design, safeguard chemical industry Production safety is of great significance.
references:
[1] Li Jin. Research on the selection methods of commonly used valves in chemical design [J]. Chemical Industry Management, 2017(35).
[2]Chen Ziqiang. Research on the selection method of valves commonly used in chemical engineering design[J]. Chemical Industry Management, 2016(14).
[3]Luo Zhonglin. Selection strategy of commonly used valves in chemical design[J]. Chemical Engineering Design and Communications, 2016(03).
Keywords: chemical design; commonly used valves; selection strategy In chemical production, the types of valves are various and play different roles, including control, isolation, and prevention of backflow, and are important components for controlling chemical production efficiency and progress. Production safety also plays a role that cannot be ignored. In the current market, the types of valves are various. If you choose to make mistakes, it will seriously affect the smooth development of chemical production, or even cause serious safety incidents. Therefore, it is an important part of chemical design to master reasonable and commonly used valve selection strategies. jobs.
1 Basic points of valve selection in chemical engineering design In chemical engineering design, in order to ensure the rationality and reliability of valve selection, the following basic points must be mastered:
First of all, it is necessary to clarify the specific use of the valve. There are tens of thousands of types of valves, and there are differences in the performance and applicable conditions of different valves. When selecting a type, it is necessary to understand the pressure, control methods, etc. of the pipeline first, and to clarify the specific requirements of the valve function and parameter indicators in order to make Targeted selection, improve the selection of reasonable; Second, select the appropriate type. In a wide variety of valves, there are significant differences in the production process and performance. In the selection process, it is necessary to first grasp the type of valve, select the appropriate valve from the same type of function, and prohibit the use of mixed valves. , determine the valve port. The valve is connected with the pipeline to constitute the chemical production system. The valve connection port is an important factor affecting its application safety. Therefore, it is necessary to pay more attention to the valve port and do a good job of selection control. Fourth, do a good job of valve quality control. Valve manufacturing materials, processes, etc. will affect the quality of the valve, in the current market, the quality of the valve varies, in the selection, the need to do a good job of valve quality testing, strict quality control, can improve the reliability of the use of the valve.
2 Specific strategies for valve selection in chemical engineering design In chemical engineering, the commonly used types of valves include gate valves, butterfly valves, ball valves, throttle valves, globe valves, and plug valves. Valve performance, characteristics, operating parameters, and applicable conditions The other aspects are the key points to be considered in the selection process. The specific selection strategy is:
2.1 Valve selection strategy In the current valve market, the gate valve occupies a considerable proportion, the basic principle is to drive the valve plate through the valve stem, to achieve the control of the lifting movement, with a light switch, good elastic memory, good airtightness , Switching operation flexibility and outstanding adjustment performance, but there are structural deficiencies, maintenance difficulties. According to the characteristics of the gate valve, in the chemical design, the gate valve has a wide range of applications, including solid particle media, steam and oil products in the chemical production, has a good effect on the use of vacuum systems, exhaust valves. In addition, in the selection of the gate valve in the production of solid particulate media, it is necessary to cooperate with the blowhole to prevent the gate valve from being blocked by particles. When the medium temperature is low, a special low-temperature gate valve needs to be selected to avoid affecting the normal use of the gate valve.
2.2 The strategy of butterfly valve selection In chemical engineering design, when the pipeline size of the project is large and the structure size is short, the butterfly valve is suitable for the rapid opening and closing of the pipeline, and the control capacity of the pipeline flow is strengthened. Air media compression and oil aspects. In the operating range of 1KPa and 80°C, the pressure loss of the butterfly valve will exceed the gate valve. Therefore, the selection of the butterfly valve also needs to take into account the pipeline pressure factor. When the pressure requirement is relatively low, the butterfly valve may be used. The gate valve has a high degree of safety.
2.3 Ball valve selection strategy Ball valve has many advantages, including good wear resistance, good sealing and long service life, has wide applicability to the medium, viscosity, low temperature, high pressure and corrosive media, can be used Ball valve is the most widely used valve in chemical design. However, in the selection of the ball valve, it is necessary to take into account the problem of the diameter. When the diameter of the ball valve is large, it is necessary to assist the turbine transmission device to complete the opening and closing of the ball valve with external force, thereby ensuring the play of the ball valve.
2.4 The strategy of globe valve selection The globe valve has a good adaptability to the operating environment, and has good ability to adjust the pressure and temperature. It can be used in high pressure and high temperature medium pipelines, but the adjustment accuracy is low and the fluid resistance is certain. The requirements apply only to pipelines with low fluid resistance values ​​and do not apply to conditions where the viscosity is high or the medium particles precipitate more. Generally speaking, the cut-off valve can be selected in the pipe with small diameter, low adjustment performance requirements or steam pipeline with DN below 200mm. In addition, when the pipeline medium is liquid or toxic gas, it is also necessary to select the cut-off valve and use the cut-off valve. Good sealing performance to prevent the leakage of liquid or toxic gas and improve the safety of chemical design. Finally, the globe gasket replacement is very convenient. In the installation operation, only the direction of the valve and the direction of the fluid can be unified, the construction is simple, and it is widely used in chemical engineering design.
2.5 Throttle valve selection strategy Throttle valve plays a significant role in energy conservation in chemical production. In the selection of throttle valve, the applicable conditions are the smaller diameter and low regulation performance of the pipeline. Compared with the cut-off valve, the two are similar in structure, but the throttling valve has more throttling components, which has obvious advantages in energy saving and is in line with the requirements of modern sustainable development. The disadvantages are mainly reflected in the low control precision and the requirement. Relatively strict piping does not apply.
2.6 Plug Valve Selection Strategy The characteristics of the plug valve are mainly the fast opening and closing speed. It is applicable to the pipeline with high requirements for start-stop, but in the media, high-temperature medium is not applicable. Suspended particles and high-viscosity media It has good applicability. In the actual chemical design, this kind of complex medium requirement restricts the use of the plug valve to a certain extent, and needs to be selected according to its applicable conditions.
3 Conclusion In summary, in the chemical design, the valve selection is very critical, will directly affect the design quality, strengthen the study of the selection of commonly used valves, master the correct selection strategy, to improve the level of chemical design, safeguard chemical industry Production safety is of great significance.
references:
[1] Li Jin. Research on the selection methods of commonly used valves in chemical design [J]. Chemical Industry Management, 2017(35).
[2]Chen Ziqiang. Research on the selection method of valves commonly used in chemical engineering design[J]. Chemical Industry Management, 2016(14).
[3]Luo Zhonglin. Selection strategy of commonly used valves in chemical design[J]. Chemical Engineering Design and Communications, 2016(03).
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