A supercritical carbon dioxide compressor dry gas seal pressure control system and method

Abstract

The invention relates to the technical field of compressors, and in particular to a supercritical carbon dioxide compressor dry gas seal pressure control system and method; the supercritical carbon dioxide compressor dry gas seal pressure control system comprises a compressor body, a balance pipe, a first pressure transmitter, an exhaust pipeline, a second pressure transmitter, a first gas charging pipeline, a first switch valve, a high-pressure storage tank, a third pressure transmitter, an air supply pipe, a regulating valve, a pressure difference transmitter and an air supply mechanism; when the compressor body is started, the air supply mechanism is adjusted to increase the pressure of the high-pressure storage tank, and by continuously comparing the values ​​of the second pressure transmitter and the third pressure transmitter, when the value of the second pressure transmitter reaches the value of the third pressure transmitter, the air supply mechanism stops supplying air to the high-pressure storage tank, the first switch valve is opened, and the high-pressure storage tank is supplied with air by the exhaust pipeline, so that the pressure control of the sealing gas at each stage can be realized, the smooth injection of the sealing gas is ensured, and the safe operation of the dry gas seal is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a dry gas seal pressure control system and method for a supercritical carbon dioxide compressor. Background Art

[0002] The closed-cycle power system using supercritical carbon dioxide as the working fluid can greatly reduce the size of equipment such as turbines and compressors. The inlet pressure of the supercritical carbon dioxide compressor in the system is close to the critical point, and the power consumption in the pressure-boosting process is low, which can greatly improve the power generation efficiency of the system. The inlet pressure of the compressor is generally 8MPa, and the outlet pressure can reach 15-20MPa. Dry gas seals are used at the inlet and outlet shaft ends, and the leakage is reduced by relying on the tiny air film formed between the dynamic and static rings of the dry gas seal. In order to ensure the formation of the air film and prevent dry friction between the dynamic and static rings, high-pressure sealing gas needs to be injected, and the pressure of the sealing gas must be higher than the gas pressure in the shell to ensure that the sealing gas flows from the dry gas seal to the medium side, flushing the sealing surface to prevent impurities in the gas in the circulation process from flowing back and damaging the sealing surface. However, the existing sealing gas is taken from the compressor outlet pipe. During the startup phase of the compressor, the outlet high pressure has not yet been established, and sealing gas cannot be provided, which affects the operation of the compressor. Summary of the invention

[0003] The purpose of the present invention is to provide a supercritical carbon dioxide compressor dry gas sealing pressure control system and method, aiming to solve the problem that the existing compressor sealing gas is taken from the compressor outlet pipeline. During the compressor startup phase, the outlet high pressure has not yet been established and sealing gas cannot be provided, which affects the operation of the compressor.

[0004] To achieve the above-mentioned object, in a first aspect, the present invention provides a supercritical carbon dioxide compressor dry gas seal pressure control system, comprising a compressor body, a balance pipe, a first pressure transmitter, an exhaust pipeline, a second pressure transmitter, a first charging pipeline, a first switch valve, a high-pressure storage tank, a third pressure transmitter, an air supply pipe, a regulating valve, a pressure differential transmitter and an air supply mechanism;

[0005] The balance pipe is connected to the compressor body and is located on one side of the compressor body; the first pressure transmitter is fixedly connected to the balance pipe and is located on one side of the balance pipe; the exhaust pipeline is connected to the compressor body and is located on one side of the compressor body; the second pressure transmitter is fixedly connected to the exhaust pipeline and is located on one side of the exhaust pipeline; the first charging pipeline is connected to the exhaust pipeline and is located on one side of the exhaust pipeline; the first switch valve is fixedly connected to the first charging pipeline and is located on one side of the first charging pipeline; the high-pressure storage tank is connected to the first charging pipeline and is located on one side of the first charging pipeline; the third pressure transmitter is arranged on the high-pressure storage tank; the air supply pipe is connected to the high-pressure storage tank, and is connected to the compressor body, and is located between the high-pressure storage tank and the compressor body; the regulating valve is fixedly connected to the air supply pipe and is located on one side of the air supply pipe; the differential pressure transmitter is arranged between the balance pipe and the air supply pipe, and the differential pressure transmitter is electrically connected to the regulating valve; the air supply mechanism is arranged on one side of the high-pressure storage tank.

[0006] Among them, the supercritical carbon dioxide compressor dry gas seal pressure control system also includes a controller; the controller is electrically connected to the first pressure transmitter, the second pressure transmitter, the first switch valve, the third pressure transmitter, the regulating valve, the differential pressure transmitter, and the gas supply mechanism respectively.

[0007] The compressor body includes a casing, a main shaft, a first-stage impeller, a first-stage wheel back seal, a first-stage dry gas seal dynamic ring, a first-stage dry gas seal static ring, a first-stage labyrinth seal, a second-stage impeller, a second-stage carbon ring seal, a second-stage dry gas seal dynamic ring, a second-stage dry gas seal static ring and a second-stage labyrinth seal;

[0008] The casing is connected to the exhaust pipe and is located on one side of the exhaust pipe; the main shaft is arranged inside the casing; the first-stage impeller is arranged at one end of the main shaft; the first-stage wheel back seal is arranged on one side of the first-stage impeller, the first-stage dry gas seal dynamic ring is arranged inside the casing, the first-stage dry gas seal static ring is arranged inside the casing, and a first-stage sealing surface is formed between the first-stage dry gas seal dynamic ring and the first-stage dry gas seal static ring; the first-stage labyrinth seal is arranged on the side of the first-stage dry gas seal dynamic ring, and a first-stage sealing cavity is formed between the first-stage labyrinth seal and the first-stage dry gas seal static ring, and the first-stage labyrinth seal and the A primary balance cavity is formed between the primary wheel back seals; the secondary impeller is arranged at one end of the main shaft away from the primary impeller; the secondary carbon ring seal is arranged on one side of the secondary impeller, the secondary dry gas seal dynamic ring is arranged inside the casing, the secondary dry gas seal static ring is arranged inside the casing, and a secondary sealing surface is formed between the secondary dry gas seal dynamic ring and the secondary dry gas seal static ring; the secondary labyrinth seal is arranged on the side of the secondary dry gas seal dynamic ring, a secondary sealing cavity is formed between the secondary labyrinth seal and the secondary dry gas seal static ring, and a secondary balance cavity is formed between the secondary labyrinth seal and the secondary carbon ring seal.

[0009] Wherein, the air supply mechanism includes an air charging component and a pressurizing component; the pressurizing component is arranged between the air charging component and the high-pressure storage tank.

[0010] Wherein, the inflation assembly includes a liquid storage tank, a liquid infusion tube, an evaporation device and a second switch valve;

[0011] The infusion tube is connected to the liquid storage tank and is located on one side of the liquid storage tank; the evaporation device is respectively connected to the infusion tube and the boosting component and is located between the infusion tube and the boosting component; the second switch valve is fixedly connected to the infusion tube and is located on the side of the infusion tube.

[0012] Wherein, the boosting assembly includes a boosting pump, an exhaust pipeline, a third switch valve, a boosting pipe, a fourth switch valve and a one-way valve;

[0013] The boost pump is connected to the evaporation device and is located on one side of the evaporation device; the exhaust pipeline is arranged at the outlet of the boost pump; the third switch valve is fixedly connected to the exhaust pipeline and is located on one side of the exhaust pipeline; the boost pipe is respectively connected to the boost pump and the high-pressure storage tank and is located between the boost pump and the high-pressure storage tank; the fourth switch valve is fixedly connected to the boost pipe and is located on one side of the boost pipe; the one-way valve is arranged on the boost pipe.

[0014] In a second aspect, the present invention further provides a method for controlling dry gas seal pressure of a supercritical carbon dioxide compressor, comprising:

[0015] When the compressor body is inflated, the first switch valve is closed, and the gas supply mechanism inflates the high-pressure storage tank to make the pressure in the balance pipe reach the specified starting pressure of the dry gas seal;

[0016] When the compressor body is started, the air supply mechanism is adjusted to increase the pressure of the high-pressure storage tank, so that the regulating valve can ensure that the differential pressure transmitter is at the set value within the adjustable range;

[0017] The values ​​of the second pressure transmitter and the third pressure transmitter are continuously compared. When the value of the second pressure transmitter reaches the value of the third pressure transmitter, the gas supply mechanism stops supplying gas to the high-pressure storage tank, the first switch valve opens, and the exhaust pipeline supplies gas to the high-pressure storage tank.

[0018] The present invention provides a supercritical carbon dioxide compressor dry gas seal pressure control system and method, wherein the high-pressure storage tank stores high-pressure carbon dioxide as a seal gas, which is injected into the compressor body through the air supply pipe after the pressure is adjusted by the regulating valve; when the compressor body is inflated (inflating means inflating the compressor body from atmospheric pressure to a pressure value at which the dry gas seal allows rotation), the first switch valve is closed, and the air supply mechanism inflates the high-pressure storage tank so that the pressure in the balance pipe reaches the specified starting pressure of the dry gas seal (at this time, all pressures in the compressor body are equal to the pressure value of the first pressure transmitter, and the pressure value of the second pressure transmitter is also equal to the pressure value of the first pressure transmitter); when the compressor body is started, the air supply mechanism is adjusted so that The pressure of the high-pressure storage tank increases, so that the regulating valve is within the adjustable range (opening 20-60%) to ensure that the differential pressure transmitter is at the set value; by continuously comparing the values ​​of the second pressure transmitter and the third pressure transmitter, when the value of the second pressure transmitter reaches the value of the third pressure transmitter, the gas supply mechanism stops supplying gas to the high-pressure storage tank, the first switch valve opens, and the exhaust pipeline supplies gas to the high-pressure storage tank. When the compressor body is shut down normally or shut down due to power failure, a certain amount of high-pressure gas is stored in the high-pressure storage tank, which can be used as a sealing gas source for a certain period of time until the compressor body completes the run-down; through the above method, the sealing gas pressure control at each stage can be achieved to ensure the smooth injection of the sealing gas and maintain the safe operation of the dry gas seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1It is a structural schematic diagram of a supercritical carbon dioxide compressor dry gas seal pressure control system of the present invention.

[0021] Figure 2 It is a structural schematic diagram of the compressor body and the exhaust pipeline of the present invention.

[0022] Figure 3 The present invention is a flow chart of a method for controlling dry gas seal pressure of a supercritical carbon dioxide compressor.

[0023] 1- compressor body, 2- balance pipe, 3- first pressure transmitter, 4- exhaust pipeline, 5- second pressure transmitter, 6- first charging pipeline, 7- first switch valve, 8- high pressure storage tank, 9- third pressure transmitter, 10- air supply pipe, 11- regulating valve, 12- differential pressure transmitter, 13- air supply mechanism, 14- controller, 15- casing, 16- main shaft, 17- first-stage impeller, 18- first-stage wheel back seal, 19- first-stage dry gas seal dynamic ring, 20- first-stage dry gas seal static ring, 21- first-stage labyrinth seal, 22- second-stage impeller, 23- Secondary carbon ring seal, 24-secondary dry gas seal dynamic ring, 25-secondary dry gas seal static ring, 26-secondary labyrinth seal, 27-first-level sealing surface, 28-first-level sealing chamber, 29-first-level balance chamber, 30-secondary sealing surface, 31-secondary sealing chamber, 32-secondary balance chamber, 33-inflating component, 34-boosting component, 35-liquid storage tank, 36-infusion tube, 37-evaporation device, 38-second switch valve, 39-boosting pump, 40-emptying pipeline, 41-third switch valve, 42-boosting pipe, 43-fourth switch valve, 44-check valve. DETAILED DESCRIPTION

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0025] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, in the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0026] See also Figure 1 to Figure 3 In the first aspect, the present invention provides a supercritical carbon dioxide compressor dry gas seal pressure control system: comprising a compressor body 1, a balance pipe 2, a first pressure transmitter 3, an exhaust pipeline 4, a second pressure transmitter 5, a first charging pipeline 6, a first switch valve 7, a high-pressure storage tank 8, a third pressure transmitter 9, an air supply pipe 10, a regulating valve 11, a pressure difference transmitter 12 and an air supply mechanism 13;

[0027] The balance pipe 2 is connected to the compressor body 1 and is located on one side of the compressor body 1; the first pressure transmitter 3 is fixedly connected to the balance pipe 2 and is located on one side of the balance pipe 2; the exhaust pipeline 4 is connected to the compressor body 1 and is located on one side of the compressor body 1; the second pressure transmitter 5 is fixedly connected to the exhaust pipeline 4 and is located on one side of the exhaust pipeline 4; the first charging pipeline 6 is connected to the exhaust pipeline 4 and is located on one side of the exhaust pipeline 4; the first switch valve 7 is fixedly connected to the first charging pipeline 6 and is located on one side of the first charging pipeline 6; the high pressure The storage tank 8 is connected to the first inflation pipeline 6 and is located on one side of the first inflation pipeline 6; the third pressure transmitter 9 is arranged on the high-pressure storage tank 8; the air supply pipe 10 is connected to the high-pressure storage tank 8 and is connected to the compressor body 1, and is located between the high-pressure storage tank 8 and the compressor body 1; the regulating valve 11 is fixedly connected to the air supply pipe 10 and is located on one side of the air supply pipe 10; the differential pressure transmitter 12 is arranged between the balancing pipe 2 and the air supply pipe 10, and the differential pressure transmitter 12 and the regulating valve 11 are electrically connected; the air supply mechanism 13 is arranged on one side of the high-pressure storage tank 8.

[0028] In this embodiment, the high-pressure storage tank 8 stores high-pressure carbon dioxide as a sealing gas, which is injected into the compressor body 1 through the air supply pipe 10 after the pressure is adjusted by the regulating valve 11; when the compressor body 1 is inflated (inflation refers to inflating the compressor body 1 from atmospheric pressure to a pressure value at which the dry gas seal allows rotation), the first switch valve 7 is closed, and the air supply mechanism 13 inflates the high-pressure storage tank 8 so that the pressure in the balance pipe 2 reaches the specified starting pressure of the dry gas seal (at this time, all pressures in the compressor body 1 are equal to the pressure value of the first pressure transmitter 3, and the pressure value of the second pressure transmitter 5 is also equal to the pressure value of the first pressure transmitter 3); when the compressor body 1 is started, the air supply mechanism 13 is adjusted to increase the pressure of the high-pressure storage tank 8. High, so that the regulating valve 11 is within the adjustable range (opening 20-60%) to ensure that the differential pressure transmitter 12 is at the set value; by constantly comparing the values ​​of the second pressure transmitter 5 and the third pressure transmitter 9, when the value of the second pressure transmitter 5 reaches the value of the third pressure transmitter 9, the gas supply mechanism 13 stops supplying gas to the high-pressure storage tank 8, the first switch valve 7 is opened, and the exhaust pipe 4 supplies gas to the high-pressure storage tank 8. When the compressor body 1 is shut down normally or shut down due to power failure, there is a certain amount of high-pressure gas in the high-pressure storage tank 8, which can be used as a sealing gas source for a certain period of time until the compressor body 1 completes the run-down; through the above method, the sealing gas pressure control at each stage can be achieved to ensure the smooth injection of the sealing gas and maintain the safe operation of the dry gas seal.

[0029] Furthermore, the supercritical carbon dioxide compressor dry gas seal pressure control system also includes a controller 14; the controller 14 is electrically connected to the first pressure transmitter 3, the second pressure transmitter 5, the first switch valve 7, the third pressure transmitter 9, the regulating valve 11, the differential pressure transmitter 12, and the gas supply mechanism 13 respectively.

[0030] In this embodiment, the first pressure transmitter 3 , the second pressure transmitter 5 , the first switch valve 7 , the third pressure transmitter 9 , the regulating valve 11 , the differential pressure transmitter 12 and the air supply mechanism 13 can be controlled by the controller 14 .

[0031] Further, the compressor body 1 includes a casing 15, a main shaft 16, a first-stage impeller 17, a first-stage wheel back seal 18, a first-stage dry gas seal dynamic ring 19, a first-stage dry gas seal static ring 20, a first-stage labyrinth seal 21, a second-stage impeller 22, a second-stage carbon ring seal 23, a second-stage dry gas seal dynamic ring 24, a second-stage dry gas seal static ring 25 and a second-stage labyrinth seal 26;

[0032] The casing 15 is connected to the exhaust pipe 4 and is located on one side of the exhaust pipe 4; the main shaft 16 is arranged inside the casing 15; the first-stage impeller 17 is arranged at one end of the main shaft 16; the first-stage wheel back seal 18 is arranged on one side of the first-stage impeller 17, the first-stage dry gas seal dynamic ring 19 is arranged inside the casing 15, the first-stage dry gas seal static ring 20 is arranged inside the casing 15, and a first-stage sealing surface 27 is formed between the first-stage dry gas seal dynamic ring 19 and the first-stage dry gas seal static ring 20; the first-stage labyrinth seal 21 is arranged on the side of the first-stage dry gas seal dynamic ring 19, and a first-stage sealing cavity 28 is formed between the first-stage labyrinth seal 21 and the first-stage dry gas seal static ring 20, and the first-stage labyrinth seal 21 and the first-stage dry gas seal dynamic ring 19 are provided. A primary balance chamber 29 is formed between the stage wheel back seals 18; the secondary impeller 22 is arranged at the end of the main shaft 16 away from the primary impeller 17; the secondary carbon ring seal 23 is arranged on one side of the secondary impeller 22, the secondary dry gas seal dynamic ring 24 is arranged inside the casing 15, the secondary dry gas seal static ring 25 is arranged inside the casing 15, and a secondary sealing surface 30 is formed between the secondary dry gas seal dynamic ring 24 and the secondary dry gas seal static ring 25; the secondary labyrinth seal 26 is arranged on the side of the secondary dry gas seal dynamic ring 24, a secondary sealing chamber 31 is formed between the secondary labyrinth seal 26 and the secondary dry gas seal static ring 25, and a secondary balance chamber 32 is formed between the secondary labyrinth seal 26 and the secondary carbon ring seal 23.

[0033] In this embodiment, the first-stage impeller 17 and the second-stage impeller 22 are suspended at both ends of the main shaft 16; the first-stage wheel back seal 18 is arranged on the back of the first-stage impeller 17, and the first-stage dry gas seal dynamic ring 19 is installed behind the first-stage wheel back seal 18; the second-stage impeller 22 is provided with the second-stage carbon ring seal 23 on the back, and the second-stage dry gas seal dynamic ring 24 is installed behind the second-stage carbon ring seal 23; a high-speed motor or gear box is arranged between the first-stage impeller 17 and the second-stage impeller 22.

[0034] The high-pressure storage tank 8 stores high-pressure carbon dioxide as sealing gas. After the pressure is adjusted by the regulating valve 11, the high-pressure carbon dioxide is respectively injected into the primary sealing chamber 28 and the secondary sealing chamber 31 through the air supply pipe 10. The secondary balancing chamber 32 is connected to the primary balancing chamber 29 through the balancing pipe 2. The pressure of the secondary balancing chamber 32 and the primary balancing chamber 29 is the same, which is equal to the pressure of the balancing pipe 2 (measured by the first pressure transmitter 3). The differential pressure transmitter 12 measures the pressure difference between the balancing pipe 2 and the pressure after the regulating valve 11, and feeds it back to the The regulating valve 11 automatically adjusts the opening to ensure that the differential pressure transmitter 12 is always at the set value, that is, to ensure that the pressure after the regulating valve 11 is always greater than the pressure of the balancing pipe 2 minus the set value, thereby ensuring that the sealing gas always flows from the primary sealing chamber 28 to the primary balancing chamber 29, and from the secondary sealing chamber 31 to the secondary balancing chamber 32, that is, to ensure the flow rate at the gap between the primary labyrinth seal 21 and the secondary labyrinth seal 26, so that impurities in the circulating process gas do not flow to the primary sealing surface 27 and the secondary sealing surface 30. The secondary carbon ring seal 23 is provided on the back of the secondary impeller 22, and a small gap is used to prevent the gas on the back of the secondary impeller 22 from leaking in large quantities to the back of the primary impeller 17 through the secondary balancing chamber 32, the balancing pipe 2, the primary balancing chamber 29, and the primary wheel back seal 18 in sequence, thereby reducing the leakage in the compressor body 1 and improving the efficiency of the compressor body 1.

[0035] Furthermore, the air supply mechanism 13 includes an air charging component 33 and a pressurizing component 34 ; the pressurizing component 34 is disposed between the air charging component 33 and the high-pressure storage tank 8 .

[0036] In this embodiment, the carbon dioxide sealing gas can be obtained through the inflation component 33, and the booster component 34 can deliver the carbon dioxide sealing gas into the high-pressure storage tank 8 and pressurize the carbon dioxide sealing gas in the high-pressure storage tank 8.

[0037] Furthermore, the inflation assembly 33 includes a liquid storage tank 35, a liquid infusion tube 36, an evaporation device 37 and a second switch valve 38;

[0038] The infusion tube 36 is connected to the liquid storage tank 35 and is located on one side of the liquid storage tank 35; the evaporation device 37 is respectively connected to the infusion tube 36 and the boosting component 34 and is located between the infusion tube 36 and the boosting component 34; the second switch valve 38 is fixedly connected to the infusion tube 36 and is located on the side of the infusion tube 36.

[0039] In this embodiment, liquid carbon dioxide is stored in the liquid storage tank 35 , and enters the evaporation device 37 through the second switch valve 38 to be evaporated into gas and sent to the booster assembly 34 .

[0040] Further, the boosting assembly 34 includes a boosting pump 39, an exhaust pipeline 40, a third switch valve 41, a boosting pipe 42, a fourth switch valve 43 and a one-way valve 44;

[0041] The boost pump 39 is connected to the evaporation device 37 and is located on one side of the evaporation device 37; the exhaust pipe 40 is arranged at the outlet of the boost pump 39; the third switch valve 41 is fixedly connected to the exhaust pipe 40 and is located on one side of the exhaust pipe 40; the boost pipe 42 is connected to the boost pump 39 and the high-pressure storage tank 8 respectively and is located between the boost pump 39 and the high-pressure storage tank 8; the fourth switch valve 43 is fixedly connected to the boost pipe 42 and is located on one side of the boost pipe 42; the one-way valve 44 is arranged on the boost pipe 42.

[0042] In this embodiment, the evaporation device 37 sends carbon dioxide into the booster pump 39 for pressurization, passes through the fourth switch valve 43 and the one-way valve 44, and flows into the high-pressure storage tank 8. The outlet of the booster pump 39 is also provided with the exhaust pipeline 40, which is controlled by the third switch valve 41.

[0043] In a second aspect, the present invention further provides a method for controlling dry gas seal pressure of a supercritical carbon dioxide compressor, comprising:

[0044] When the S1 compressor body 1 is inflated, the first switch valve 7 is closed, and the gas supply mechanism 13 inflates the high-pressure storage tank 8 to make the pressure in the balance pipe 2 reach the specified starting pressure of the dry gas seal;

[0045] When the compressor body 1 is inflated (inflation refers to inflating the compressor body 1 from atmospheric pressure to a pressure value at which the dry gas seal allows rotation), the first switch valve 7 is closed and the third switch valve 41 is closed, the second switch valve 38 and the fourth switch valve 43 are opened, and the air supply mechanism 13 inflates the high-pressure storage tank 8 so that the pressure in the balance pipe 2 reaches the specified starting pressure of the dry gas seal (at this time, all pressures in the compressor body 1 are equal to the pressure value of the first pressure transmitter 3, and the pressure value of the second pressure transmitter 5 is also equal to the pressure value of the first pressure transmitter 3).

[0046] When the S2 compressor body 1 is started, the air supply mechanism 13 is adjusted to increase the pressure of the high-pressure storage tank 8, so that the regulating valve 11 is within the adjustable range (opening degree 20-60%) to ensure that the differential pressure transmitter 12 is at the set value;

[0047] S3 continuously compares the values ​​of the second pressure transmitter 5 and the third pressure transmitter 9. When the value of the second pressure transmitter 5 reaches the value of the third pressure transmitter 9, the gas supply mechanism 13 stops supplying gas to the high-pressure storage tank 8, the first switch valve 7 opens, and the exhaust pipeline 4 supplies gas to the high-pressure storage tank 8;

[0048] The controller 14 continuously compares the values ​​of the second pressure transmitter 5 and the third pressure transmitter 9. As the speed of the compressor body 1 increases, the value of the second pressure transmitter 5 gradually increases. When the value of the second pressure transmitter 5 reaches the value of the third pressure transmitter 9, the controller 14 performs the following operations in sequence: first, the third switch valve 41 is controlled to open, and the exhaust pipeline 40 is connected to the atmosphere. At this time, the one-way valve 44 can prevent the backflow of high-pressure gas; the fourth switch valve 43 is controlled to close; the second switch valve 38 is controlled to close, and the liquid carbon dioxide is disconnected; the booster pump 39 and the evaporation device 37 are manually shut down; then the controller 14 controls the first switch valve 7 to open, and the exhaust pipeline 4 and the first charging pipeline 6 supply gas to the high-pressure storage tank 8. When the compressor body 1 is shut down normally or shut down due to power failure, a certain amount of high-pressure gas is stored in the high-pressure storage tank 8, which can be used as a sealing gas source for a certain period of time until the compressor body 1 completes the rotation; through the above method, the sealing gas pressure control at each stage can be achieved to ensure the smooth injection of sealing gas and maintain the safe operation of dry gas sealing.

[0049] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A supercritical carbon dioxide compressor dry gas seal pressure control system, characterized in that: It includes a compressor body, a balance pipe, a first pressure transmitter, an exhaust pipeline, a second pressure transmitter, a first charging pipeline, a first switch valve, a high-pressure storage tank, a third pressure transmitter, an air supply pipe, a regulating valve, a differential pressure transmitter and an air supply mechanism; The balance pipe is connected to the compressor body and is located on one side of the compressor body; the first pressure transmitter is fixedly connected to the balance pipe and is located on one side of the balance pipe; the exhaust pipeline is connected to the compressor body and is located on one side of the compressor body; the second pressure transmitter is fixedly connected to the exhaust pipeline and is located on one side of the exhaust pipeline; the first charging pipeline is connected to the exhaust pipeline and is located on one side of the exhaust pipeline; the first switch valve is fixedly connected to the first charging pipeline and is located on one side of the first charging pipeline; the high-pressure storage tank is connected to the first charging pipeline and is located on one side of the first charging pipeline; the third pressure transmitter is arranged on the high-pressure storage tank; the air supply pipe is connected to the high-pressure storage tank, and is connected to the compressor body, and is located between the high-pressure storage tank and the compressor body; the regulating valve is fixedly connected to the air supply pipe and is located on one side of the air supply pipe; the differential pressure transmitter is arranged between the balance pipe and the air supply pipe, and the differential pressure transmitter is electrically connected to the regulating valve; the air supply mechanism is arranged on one side of the high-pressure storage tank.

2. A supercritical carbon dioxide compressor dry gas seal pressure control system as claimed in claim 1, characterized in that: The supercritical carbon dioxide compressor dry gas seal pressure control system also includes a controller; the controller is electrically connected to the first pressure transmitter, the second pressure transmitter, the first switch valve, the third pressure transmitter, the regulating valve, the differential pressure transmitter, and the gas supply mechanism respectively.

3. A supercritical carbon dioxide compressor dry gas seal pressure control system as claimed in claim 2, characterized in that: The compressor body comprises a casing, a main shaft, a first-stage impeller, a first-stage wheel back seal, a first-stage dry gas seal dynamic ring, a first-stage dry gas seal static ring, a first-stage labyrinth seal, a second-stage impeller, a second-stage carbon ring seal, a second-stage dry gas seal dynamic ring, a second-stage dry gas seal static ring and a second-stage labyrinth seal; The casing is connected to the exhaust pipe and is located on one side of the exhaust pipe; the main shaft is arranged inside the casing; the first-level impeller is arranged at one end of the main shaft; the first-level wheel back seal is arranged on one side of the first-level impeller, the first-level dry gas seal dynamic ring is arranged inside the casing, the first-level dry gas seal static ring is arranged inside the casing, and a first-level sealing surface is formed between the first-level dry gas seal dynamic ring and the first-level dry gas seal static ring; the first-level labyrinth seal is arranged on the side of the first-level dry gas seal dynamic ring, a first-level sealing cavity is formed between the first-level labyrinth seal and the first-level dry gas seal static ring, and a first-level balancing cavity is formed between the first-level labyrinth seal and the first-level wheel back seal; the second-level impeller is arranged on one end of the main shaft away from the first-level impeller; the second-level carbon ring seal is arranged on one side of the second-level impeller, the second-level dry gas seal dynamic ring is arranged inside the casing, the second-level dry gas seal static ring is arranged inside the casing, and a second-level sealing surface is formed between the second-level dry gas seal dynamic ring and the second-level dry gas seal static ring; The secondary labyrinth seal is arranged on the side of the secondary dry gas seal dynamic ring, a secondary sealing cavity is formed between the secondary labyrinth seal and the secondary dry gas seal static ring, and a secondary balancing cavity is formed between the secondary labyrinth seal and the secondary carbon ring seal.

4. A supercritical carbon dioxide compressor dry gas seal pressure control system as claimed in claim 3, characterized in that: The air supply mechanism includes an air charging component and a pressurizing component; the pressurizing component is arranged between the air charging component and the high-pressure storage tank.

5. A supercritical carbon dioxide compressor dry gas seal pressure control system as claimed in claim 4, characterized in that: The gas filling assembly includes a liquid storage tank, a liquid infusion tube, an evaporation device and a second switch valve; The infusion tube is connected to the liquid storage tank and is located on one side of the liquid storage tank; the evaporation device is respectively connected to the infusion tube and the boosting component and is located between the infusion tube and the boosting component; the second switch valve is fixedly connected to the infusion tube and is located on the side of the infusion tube.

6. A supercritical carbon dioxide compressor dry gas seal pressure control system as claimed in claim 5, characterized in that: The boosting assembly includes a boosting pump, an exhaust pipeline, a third switch valve, a boosting pipe, a fourth switch valve and a one-way valve; The boost pump is connected to the evaporation device and is located on one side of the evaporation device; the exhaust pipeline is arranged at the outlet of the boost pump; the third switch valve is fixedly connected to the exhaust pipeline and is located on one side of the exhaust pipeline; the boost pipe is respectively connected to the boost pump and the high-pressure storage tank and is located between the boost pump and the high-pressure storage tank; the fourth switch valve is fixedly connected to the boost pipe and is located on one side of the boost pipe; the one-way valve is arranged on the boost pipe.

7. A supercritical carbon dioxide compressor dry gas seal pressure control method, applied to a supercritical carbon dioxide compressor dry gas seal pressure control system as claimed in any one of claims 1 to 6, characterized in that: include: When the compressor body is inflated, the first switch valve is closed, and the air supply mechanism inflates the high-pressure storage tank to make the pressure in the balance pipe reach the specified starting pressure of the dry gas seal; When the compressor body is started, the air supply mechanism is adjusted to increase the pressure of the high-pressure storage tank, so that the regulating valve can ensure that the differential pressure transmitter is at the set value within the adjustable range; The values ​​of the second pressure transmitter and the third pressure transmitter are continuously compared. When the value of the second pressure transmitter reaches the value of the third pressure transmitter, the gas supply mechanism stops supplying gas to the high-pressure storage tank, the first switch valve opens, and the exhaust pipeline supplies gas to the high-pressure storage tank.

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