A propylene compressor dry gas seal gas switching system

Abstract

The utility model relates to propylene compressor technical field, concretely relates to a propylene compressor dry gas seal gas switching system, through the stable high pressure nitrogen gas of sealing nitrogen import in starting and stopping machine stage provides as the first stage seal gas, avoided the demand of buying professional equipment production first stage seal gas, sealing nitrogen regulating valve and differential pressure transmitter interlock, accurate control nitrogen pressure, ensure the sealing effect while reducing nitrogen consumption, heater and temperature sensor interlock, keep the main seal gas that enters dry gas seal has 20 DEG C superheat, improve seal reliability, the combination design of first bypass switch valve, second bypass switch valve and first connection switch valve, third connection switch valve, outlet check valve, realized after starting completion automatic switching to compressor outlet process gas as first stage seal gas, further reduced the operation cost, the whole system passes through the automatic switching mechanism, effectively solved the technical problem of high cost of user.

Description

Technical Field

[0001] This utility model relates to the field of propylene compressor technology, and in particular to a dry gas sealing gas switching system for propylene compressors. Background Technology

[0002] Propylene compressors play a crucial role in industrial production. They are primarily used to compress propylene gas to the required pressure and are widely used in chemical, petroleum, and pharmaceutical industries. They are key equipment for gas compression and transportation in industrial production. Propylene is an important chemical raw material, mainly used in the production of polypropylene, acrylonitrile, propylene oxide, and other chemicals. Propylene is an organic compound, a colorless, odorless gas with a slightly sweet smell. It is flammable and burns with a bright flame. Its explosive limits in air are 2% to 11.1%. High concentrations of propylene have an anesthetic effect on humans, while lower concentrations may irritate the eyes and skin.

[0003] Due to the above characteristics of propylene, propylene leakage poses a great danger to the environment. In order to reduce the leakage of propylene compressor seals, especially propylene compressors operating under high outlet pressure conditions, series dry gas seals are generally selected. Series dry gas seals have a better sealing effect. The sealing gas is divided into a first-stage sealing gas and a second-stage sealing gas. The pressure of the first-stage sealing gas is much higher than that of the second-stage sealing gas. Because the pressure of the first-stage sealing gas is higher, and this gas is allowed to enter the compressor process pipeline without reacting with the process gas.

[0004] However, due to the above reasons, it is difficult for general users to find a suitable compressed air source as the primary sealing air source. To solve this problem, users generally need to purchase professional equipment to continuously produce the primary sealing air source, which greatly increases the user's operating costs. Summary of the Invention

[0005] The purpose of this utility model is to provide a dry gas and sealing gas switching system for propylene compressors, which aims to solve the technical problem that, due to the above reasons, it is difficult for general users to find a suitable compressed gas source as the first-stage sealing gas source. To solve this problem, users generally need to purchase professional equipment to continuously produce the first-stage sealing gas source, which greatly increases the user's operating costs.

[0006] To achieve the above objectives, this utility model employs a dry gas-sealed gas switching system for a propylene compressor, comprising a sealed nitrogen inlet, a heater, a filter, and a compressor. A sealed outlet valve is provided at the outlet end of the sealed nitrogen inlet. A sealed nitrogen regulating valve is provided at one outlet end of the sealed outlet valve, and an inlet check valve is provided at the other outlet end of the sealed outlet valve. A first bypass switch valve is provided at one bypass end of the heater, and a second bypass switch valve is provided at the other bypass end. A first connecting switch valve is provided at the outlet ends of the first and second bypass switch valves, with the first bypass switch valve located at the inlet end of the first connecting switch valve and the second bypass switch valve located at the outlet end of the second bypass switch valve. The inlet check valve communicates with the first connecting switch valve and is located at the inlet end of both the first connecting switch valve and the first bypass switch valve. The filter communicates with the first connecting switch valve and is located at the outlet end of both the first connecting switch valve and the second bypass switch valve. The filter communicates with the compressor and is located at the inlet end of the compressor. The compressor is connected between the inlet check valve, the first bypass switch valve, and the outlet end of the first connecting switch valve.

[0007] The compressor is equipped with a second connecting switch valve, and a flare is installed at one end of the second connecting switch valve.

[0008] A third connecting valve and an outlet check valve are provided between the compressor and the outlet ends of the inlet check valve, the first bypass switch valve, and the first connecting switch valve, and the outlet check valve is connected between the outlet ends of the inlet check valve, the first bypass switch valve, and the first connecting switch valve.

[0009] The propylene compressor dry gas sealing gas switching system also includes a differential pressure transmitter, which is located between the sealing nitrogen regulating valve and the compressor.

[0010] The propylene compressor dry gas sealing gas switching system also includes a temperature sensor, which is located between the heater and the filter, at the outlet end of the filter, and is interlocked with the heater.

[0011] This utility model discloses a dry gas sealing gas switching system for a propylene compressor. During start-up and shutdown, a stable high-pressure nitrogen gas is provided as the first-stage sealing gas through the sealing nitrogen inlet, eliminating the need to purchase specialized equipment to produce the first-stage sealing gas. The sealing nitrogen regulating valve is interlocked with the differential pressure transmitter to precisely control the nitrogen pressure, ensuring sealing effectiveness while reducing nitrogen consumption. The heater is interlocked with the temperature sensor to maintain a 20°C superheat for the main sealing gas entering the dry gas seal, improving sealing reliability. The combined design of the first bypass switch valve, the second bypass switch valve, the first connecting switch valve, the third connecting switch valve, and the outlet check valve enables automatic switching to the compressor outlet process gas as the first-stage sealing gas after startup, further reducing operating costs. The entire system, through its automatic switching mechanism, effectively solves the technical problem of high costs for users. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the dry gas sealing gas switching system of the propylene compressor of this utility model.

[0014] 1-Sealed nitrogen regulating valve, 2-Inlet check valve, 3-First bypass switch valve, 4-Heater, 5-Second bypass switch valve, 6-Temperature sensor, 7-Filter, 8-Differential pressure transmitter, 9-Compressor, 10-Sealed outlet valve, 11-Second connecting switch valve, 12-Outlet check valve, 13-First connecting switch valve. Detailed Implementation

[0015] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0016] Please see Figure 1This utility model provides a dry gas sealing gas switching system for a propylene compressor, including a sealing nitrogen inlet, a heater 4, a filter 7, and a compressor 9. A sealing outlet valve 10 is provided at the outlet end of the sealing nitrogen inlet. A sealing nitrogen regulating valve 1 is provided at one outlet end of the sealing outlet valve 10, and an inlet check valve 2 is provided at the other outlet end of the sealing outlet valve 10. A first bypass switch valve 3 is provided at one bypass end of the heater 4, and a second bypass switch valve 5 is provided at the other bypass end. A first connecting switch valve 13 is provided at the outlet ends of the first bypass switch valve 3 and the second bypass switch valve 5, and the first bypass switch valve 3 is located at the... The first connecting switch valve 13 is located at its inlet end, the second bypass switch valve 5 is located at its outlet end, the inlet check valve 2 is connected to the first connecting switch valve 13 and is located at the inlet end of the first connecting switch valve 13 and the first bypass switch valve 3, the filter 7 is connected to the first connecting switch valve 13 and is located at the outlet end of the first connecting switch valve 13 and the second bypass switch valve 5, the filter 7 is connected to the compressor 9 and is located at the inlet end of the compressor 9, and the compressor 9 is connected between the inlet check valve 2, the first bypass switch valve 3 and the outlet end of the first connecting switch valve 13.

[0017] In this embodiment, the combined design of the sealed nitrogen inlet, the sealed outlet valve 10, the sealed nitrogen regulating valve 1, and the inlet check valve 2 enables the use of stable high-pressure nitrogen as the first-stage sealing gas source during start-up and shutdown, avoiding the need for users to purchase specialized equipment to produce the first-stage sealing gas, thereby significantly reducing initial investment and operating costs. The heater 4, through the cooperation of the first bypass switch valve 3, the second bypass switch valve 5, and the first connecting switch valve 13, automatically switches to the process gas outlet of the compressor 9 as the sealing gas source during stable operation, further optimizing the gas source selection. The filter 7 ensures the cleanliness of the gas entering the compressor 9, preventing impurities from damaging the seals and extending the equipment's service life. As a core component, the compressor 9, through its interconnection design with various valves, achieves seamless switching of the gas source, ensuring the continuity and reliability of system operation.

[0018] Furthermore, the compressor 9 is provided with a second connecting switch valve 11, and a flare is provided at one end of the second connecting switch valve 11.

[0019] In this embodiment, the flare device can safely release process gas in case of system malfunction or emergency shutdown, preventing equipment damage or safety accidents caused by pressure buildup, and improving the system's safety and emergency response capabilities.

[0020] Furthermore, a third connecting valve and an outlet check valve 12 are provided between the compressor 9 and the outlet ends of the inlet check valve 2, the first bypass switch valve 3 and the first connecting switch valve 13, and the outlet check valve 12 is connected between the outlet ends of the inlet check valve 2, the first bypass switch valve 3 and the first connecting switch valve 13.

[0021] In this embodiment, the outlet check valve 12 can prevent process gas from flowing back into the sealing gas path, avoiding reverse pressure impact on the seal. At the same time, the third connection switch valve provides the system with an additional shut-off function, which facilitates gas path isolation during maintenance and repair, and improves the operability and safety of the system.

[0022] Furthermore, the dry gas and sealing gas switching system of the propylene compressor 9 also includes a differential pressure transmitter 8, which is located between the sealing nitrogen regulating valve 1 and the compressor 9.

[0023] In this embodiment, the differential pressure transmitter 8 monitors the pressure difference between the main sealing gas and the sealing chamber of the compressor 9 in real time, and forms a closed-loop control with the sealing nitrogen regulating valve 1. By precisely adjusting the nitrogen pressure, the differential pressure range of 0.22MPa.a-0.28MPa.a is maintained, which ensures the sealing effect and avoids excessive nitrogen consumption, thereby reducing operating costs while ensuring sealing reliability.

[0024] Furthermore, the dry gas sealing gas switching system of the propylene compressor 9 also includes a temperature sensor 6, which is disposed between the heater 4 and the filter 7, and is located at the outlet end of the filter 7. The temperature sensor 6 is interlocked with the heater 4.

[0025] In this embodiment, the temperature sensor 6 is installed between the heater 4 and the filter 7 and is interlocked with the heater 4 to maintain the main sealing gas entering the dry gas seal of the compressor 9 at a superheat of 20°C. The differential pressure transmitter 8 monitors the pressure difference between the main sealing gas and the sealing chamber of the compressor 9 in real time, and the sealing nitrogen regulating valve 1 is interlocked to keep the pressure difference before and after the sealing nitrogen regulating valve 1 between 0.22 MPa and 0.28 MPa.

[0026] In this invention, upon startup, the outlet check valve 12 and the sealed outlet valve 10 are opened, the first bypass switch valve 3 and the second bypass switch valve 5 are closed, and the sealed nitrogen regulating valve 1 is opened simultaneously. The maximum source pressure of the sealing nitrogen is 2.8 MPa.a. When the pressure difference between the valve and the sealing chamber pressure of the compressor 9 is less than 0.2 MPa.a, the valve automatically and gradually opens until the pressure difference between the valve and the sealing chamber pressure of the compressor 9 is greater than 0.22 MPa. At this point, the valve stops opening and maintains the current opening. Since nitrogen is not easily liquefied after expanding through the dry gas sealing body, when nitrogen is used as the main sealing gas, it can be introduced into the dry gas seal without overheating. When the pressure difference between the sealed nitrogen regulating valve 1 and the sealing chamber pressure of the compressor 9 is greater than 0.3 MPa.a, the valve automatically and gradually closes until the pressure difference between the valve and the sealing chamber pressure of the compressor 9 is less than 0.28 MPa. At this point, the valve stops closing and maintains the current opening. After the compressor 9 has finished starting, due to the stable speed of the compressor 9... Once the system stabilizes, the outlet pressure of compressor 9 reaches 3.1 MPa, and the sealing chamber pressure reaches 2.5 MPa. First, open the first bypass valve 3 and the second bypass valve 5, then gradually close the first connecting valve 13. At this time, the heater 4 and the temperature sensor 6 are interlocked, maintaining the sealing gas after the heater 4 as a superheated gas of 20°C. Then, gradually open the second connecting valve 11 between the compressor outlet and the process gas, and then gradually open the third connecting valve between the compressor outlet and the process gas. Since the process gas pressure at the compressor outlet is 0.6 MPa higher than the sealing chamber pressure of compressor 9, and the pressure after the sealing nitrogen regulating valve 1 is higher than the pressure after the inlet check valve 2, nitrogen cannot be used as the first-stage sealing gas source to enter the first-stage dry gas sealing gas source of compressor 9 through the inlet check valve 2. The process gas at the compressor outlet automatically replaces nitrogen as the first-stage dry gas sealing gas source.

[0027] During shutdown, as the speed of compressor 9 gradually decreases, the pressure of the process gas at the compressor 9 outlet decreases. When the pressure of the process gas at the compressor 9 outlet is lower than the maximum gas source pressure of nitrogen (2.8 MPa), the gas pressure after the outlet check valve 12 is higher than the pressure before the valve. At this time, the process gas cannot pass through the outlet check valve 12. Nitrogen enters the dry gas seal of compressor 9 through the sealing nitrogen regulating valve 1, replacing the process gas at the compressor 9 outlet as the first-stage sealing gas source for the dry gas seal. After compressor 9 completely stops, the pressure in the compressor 9 system is released, and the shutdown is completed. All valves are then closed.

[0028] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Those skilled in the art can understand that implementing all or part of the above-described embodiments and making equivalent changes in accordance with the claims of the present utility model are still within the scope of the utility model.

Claims

1. A dry gas sealing gas switching system for a propylene compressor, characterized in that, The system includes a sealed nitrogen inlet, a heater, a filter, and a compressor. A sealed outlet valve is provided at the outlet end of the sealed nitrogen inlet. A sealed nitrogen regulating valve is provided at one outlet end of the sealed outlet valve, and an inlet check valve is provided at the other outlet end of the sealed outlet valve. A first bypass switch valve is provided at one bypass end of the heater, and a second bypass switch valve is provided at the other bypass end. A first connecting switch valve is provided at the outlet ends of the first and second bypass switch valves, with the first bypass switch valve located at the inlet end of the first connecting switch valve and the second bypass switch valve located at the outlet end of the second bypass switch valve. The inlet check valve communicates with the first connecting switch valve and is located at the inlet end of both the first connecting switch valve and the first bypass switch valve. The filter communicates with the first connecting switch valve and is located at the outlet end of both the first connecting switch valve and the second bypass switch valve. The filter communicates with the compressor and is located at the inlet end of the compressor. The compressor is connected between the inlet check valve, the first bypass switch valve, and the outlet end of the first connecting switch valve.

2. The propylene compressor dry gas sealing gas switching system as described in claim 1, characterized in that, The compressor is equipped with a second connecting switch valve, and a flare is provided at one end of the second connecting switch valve.

3. The propylene compressor dry gas sealing gas switching system as described in claim 2, characterized in that, A third connecting valve and an outlet check valve are provided between the compressor and the outlet end of the inlet check valve, the first bypass switch valve, and the first connecting switch valve, and the outlet check valve is connected between the outlet end of the inlet check valve, the first bypass switch valve, and the first connecting switch valve.

4. The propylene compressor dry gas sealing gas switching system as described in claim 3, characterized in that, The propylene compressor dry gas sealing gas switching system also includes a differential pressure transmitter, which is located between the sealing nitrogen regulating valve and the compressor.

5. The propylene compressor dry gas sealing gas switching system as described in claim 4, characterized in that, The propylene compressor dry gas sealing gas switching system also includes a temperature sensor, which is located between the heater and the filter, and at the outlet end of the filter. The temperature sensor is interlocked with the heater.

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