Chloromethane screw compressor sealing system

Abstract

The utility model relates to a sealing technology of a screw compressor, in particular to a sealing system of a chloromethane screw compressor, which not only can meet the variable speed requirement of the screw compressor, but also can be suitable for the working condition that chloromethane gas contains a few impurities, and comprises a female rotor and a male rotor which are arranged in a compressor shell, the two ends of the female rotor and the two ends of the male rotor are connected with bearing mechanisms respectively, and the two sides of the female rotor and the two sides of the male rotor are each provided with a carbon ring seal and a double-end-face mechanical seal.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of sealing technology of screw compressor, specifically a methyl chloride screw compressor sealing system. BACKGROUND

[0002] Methyl chloride is an important methylating agent in organic synthesis in chemical industry, and its process flow needs to compress methyl chloride into high-pressure gas. Due to the characteristics of flammable and explosive, oil and water prohibited, the past generally uses reciprocating piston compressor to compress methyl chloride. In recent years, for the purpose of reducing cost and increasing efficiency, screw compressor with dry gas seal is used to compress methyl chloride. However, dry gas seal is generally used for sealing of screw compressor with constant speed, and is not suitable for use on screw compressor with variable speed. SUMMARY

[0003] To solve the above technical problems, the utility model provides a kind of methyl chloride screw compressor sealing system, which can meet the variable speed requirement of screw compressor and be suitable for the working condition that methyl chloride gas contains a little impurity.

[0004] The technical scheme is as follows: a kind of methyl chloride screw compressor sealing system, which comprises a female rotor and a male rotor installed in a compressor housing, and the two ends of the female rotor and the male rotor are connected to a bearing mechanism, characterized in that the two sides of the female rotor and the male rotor are respectively provided with carbon ring seal and double-end mechanical seal.

[0005] Further characterized in that the carbon ring seal comprises an inlet end carbon ring seal and an outlet end carbon ring seal, the inlet end carbon ring seal and the outlet end carbon ring seal are respectively connected to a first seal gas pipeline and a second seal gas pipeline, a first regulating valve and a first pressure gauge are arranged on the first seal gas pipeline, the outlet end carbon ring seal is further connected to a compressor inlet pipe through a balance pipe, a second pressure gauge is installed on the balance pipe, a second regulating valve is arranged on the second seal gas pipeline, and the balance pipe and the second seal gas pipeline are connected to a differential pressure transmitter.

[0006] The double-end mechanical seal comprises an inlet end double-end mechanical seal and an outlet end double-end mechanical seal, the inlet end double-end mechanical seal comprises an inlet end female rotor seal and an inlet end male rotor seal, the outlet end double-end mechanical seal comprises an outlet end female rotor seal and an outlet end male rotor seal, the inlet end female rotor seal, the inlet end male rotor seal, the outlet end female rotor seal and the outlet end male rotor seal are connected to an oil inlet main pipe through an oil supply pipe, a stop valve, an orifice plate and a pressure gauge are arranged on the oil supply pipe, and a third pressure gauge and a self-operated differential pressure regulating valve are arranged on the oil return pipe connected to the outlet end double-end mechanical seal.

[0007] The carbon ring sealing and the double-end mechanical sealing are adopted to seal the compressor in the cavity, and the sealing gas pressure and the sealing oil pressure are reasonably controlled to ensure the sealing property, so that the variable speed requirement of the screw compressor can be met, and the working condition that the chloromethane gas contains a little impurity can be applied. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is the internal front view of the compressor of the utility model;

[0009] Figure 2 It is the internal plan view of the compressor of the utility model;

[0010] Figure 3 It is the carbon ring sealing process flow chart;

[0011] Figure 4 It is the double-end mechanical sealing process flow chart. DETAILED DESCRIPTION

[0012] As shown in Figure 1 , Figure 2 A chloromethane screw compressor sealing system, which comprises a female rotor 3 and a male rotor 7 installed in a compressor shell 1, both ends of the female rotor 3 and the male rotor 7 are connected with bearing mechanisms 5, the bearing mechanisms 5 comprise bearings and their supports, both sides of the female rotor 3 and the male rotor 7 are provided with carbon ring sealings and double-end mechanical sealings, the carbon ring sealings comprise an inlet carbon ring sealing 2 and an outlet carbon ring sealing 4, the double-end mechanical sealings comprise an inlet double-end mechanical sealing 8 and an outlet double-end mechanical sealing 6, one end of the female rotor 3 and the male rotor 7 is connected with a meshing synchronous gear 9.

[0013] As shown in Figure 3 The inlet carbon ring sealing 2 and the outlet carbon ring sealing 4 are connected with a first sealing gas pipeline 10 and a second sealing gas pipeline 11 respectively, the first sealing gas pipeline 10 and the second sealing gas pipeline 11 are connected with a sealing gas main pipe 12, the sealing gas main pipe 12 is provided with a main pipe pressure gauge PG01, a differential pressure gauge PDG01 and a filter 13, the first sealing gas pipeline 10 is provided with a first regulating valve PCV01 and a first pressure gauge PG02, the first regulating valve PCV01 is a self-powered pressure regulating valve, the outlet carbon ring sealing 4 is further connected with a compressor inlet pipe 15 through a balance pipe 14, the compressor inlet pipe 15 introduces process gas into the compressor, the balance pipe 14 is provided with a second pressure gauge PG03, the second sealing gas pipeline 11 is provided with a second regulating valve PV01, the balance pipe 14 and the second sealing gas pipeline 11 are connected with a differential pressure transmitter PDT01, and the differential pressure transmitter PDT01 feeds back a differential pressure signal to the second regulating valve PV01.

[0014] As shown in Figure 4As shown, the intake end double face mechanical seal includes an intake end female rotor seal and an intake end male rotor seal, and the exhaust end double face mechanical seal includes an exhaust end female rotor seal and an exhaust end male rotor seal. The intake end female rotor seal, the intake end male rotor seal, the exhaust end female rotor seal and the exhaust end male rotor seal are connected to an oil supply main pipe 17 through four oil supply pipes 16. A pressure transmitter PT1 is arranged on the oil supply main pipe 17. The four oil supply pipes 16 are provided with stop valves (J04, J03, J02, J01), orifices (R04, R03, R02, R01) and pressure gauges (PG05, PG04, PG03, PG02). The oil supply pressure can be changed by adjusting the opening degree of the stop valves, and the oil supply amount is limited. The oil return pipe 18 connected to the exhaust end double face mechanical seal is provided with a third pressure gauge PG01 and a self-operated pressure differential regulating valve PDCV01. The oil return pipe 18 connected to the exhaust end double face mechanical seal and the oil return pipe 19 connected to the intake end double face mechanical seal are combined into an oil return main pipe 20 for discharge. The oil return pipe 19 is further provided with a stop valve J05, an orifice R05 and a pressure gauge PG06. The oil return pipe 18 and the oil return pipe 19 are further respectively provided with a thermometer TG1 and a thermometer TG2.

[0015] See Figure 3 As shown, the carbon ring sealing process flow is as follows: the sealing gas is divided into two paths after passing through the filter 13. One path enters the intake end carbon ring seal 2 through the first regulating valve PCV01, and the other path enters the exhaust end carbon ring seal 4 through the second regulating valve PV01. For the intake end carbon ring seal 2, the compressor inlet process gas has stable and low temperature and pressure, and is not easy to produce polymer. Therefore, the gap between the intake end carbon ring seal 2 and the shaft is free of impurities, and the process gas pressure in the gap is a fixed value. After the sealing gas pressure is adjusted by the first regulating valve PCV01 (the sealing gas pressure of the intake end is higher than the process gas intake pressure), the pressure of the first pressure gauge PG02 is stable, which can ensure that the process gas cannot leak from the intake end carbon ring seal 2. For the exhaust end carbon ring seal 4, the process gas is compressed by the compressor and is high in temperature and pressure, which may cause polymer to block in the gap between the exhaust end carbon ring seal 4 and the shaft, and thus the pressure of the process gas in the exhaust end carbon ring seal 4 is variable (the pressure can be measured by the second pressure gauge PG03). The second regulating valve PV01 adjusts the sealing gas pressure of the exhaust end carbon ring seal 4 to be always 0.05 MPa higher than the pressure in the balance pipe 14 through the feedback signal of the pressure differential transmitter PDT01, thereby playing a sealing role. The sealing gas refers to high-pressure chloromethane gas, and the process gas refers to chloromethane gas.

[0016] See Figure 4As shown, the double-end-face mechanical seal process flow; high-pressure sealing oil through the inlet is divided into 4 oil supply pipes, respectively into the inlet end female rotor mechanical seal, inlet end male rotor mechanical seal, exhaust end female rotor mechanical seal, exhaust end male rotor mechanical seal, sealing oil through the inlet end double-end-face mechanical seal and exhaust end double-end-face mechanical seal after the collection to the oil return pipe discharge. For the inlet end double-end-face mechanical seal 8, because the inlet end carbon ring seal 2 sealing gas pressure is fixed, its oil supply pressure only needs to be higher than the sealing gas pressure, generally high 0.1MPa. For the exhaust end double-end-face mechanical seal 4, the exhaust end carbon ring seal 4 sealing gas pressure is variable, the sealing oil pressure needs to be higher than the sealing gas pressure, so the self-acting differential pressure regulating valve PDCV01 is installed on the oil return pipe of the exhaust end double-end-face mechanical seal 6, to ensure that the pressure difference of the two pressure points is stable at 0.1MPa, the high-pressure side of the pressure point is the exhaust end double-end-face mechanical seal 6 oil return pressure, the low-pressure side pressure point is the exhaust end carbon ring seal 4 gas pressure, there may be a small amount of sealing oil leaked into the gap between the mechanical seal and the carbon ring seal, which can be discharged after shutdown Figure 3 V01, V02, V03, V04 hand valves of the medium carbon ring seal blowdown line. Among them, the sealing oil refers to high-pressure lubricating oil.

Claims

1. A methyl chloride screw compressor seal system comprising a female rotor and a male rotor installed in a compressor housing, both ends of the female rotor and the male rotor are connected with bearing mechanisms, respectively, characterized in that, The female rotor and the male rotor are respectively provided with carbon ring seals and double-end mechanical seals on both sides.

2. A methyl chloride screw compressor seal system as claimed in claim 1, wherein, The carbon ring seals include an intake end carbon ring seal and an exhaust end carbon ring seal, the intake end carbon ring seal and the exhaust end carbon ring seal are respectively connected with a first seal gas pipeline and a second seal gas pipeline, the first seal gas pipeline is provided with a first regulating valve and a first pressure gauge, the exhaust end carbon ring seal is further connected with a compressor intake pipeline through a balance pipeline, the balance pipeline is provided with a second pressure gauge, the second seal gas pipeline is provided with a second regulating valve, and the balance pipeline and the second seal gas pipeline are connected with a differential pressure transmitter.

3. A methyl chloride screw compressor seal system as claimed in claim 1, wherein, The double-end mechanical seals include an intake end double-end mechanical seal and an exhaust end double-end mechanical seal, the intake end double-end mechanical seal includes an intake end female rotor mechanical seal and an intake end male rotor mechanical seal, the exhaust end double-end mechanical seal includes an exhaust end female rotor mechanical seal and an exhaust end male rotor mechanical seal, the intake end female rotor mechanical seal, the intake end male rotor mechanical seal, the exhaust end female rotor mechanical seal and the exhaust end male rotor mechanical seal are connected with an oil supply main pipeline through oil supply pipelines, the oil supply pipelines are provided with stop valves, orifices and pressure gauges, and the oil return pipeline connected with the exhaust end double-end mechanical seal is provided with a third pressure gauge and a self-operated differential pressure regulating valve.

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