Dry gas seal near zero leakage and working medium recovery system

Abstract

The application discloses a kind of dry gas seal near zero leakage and working medium recovery system, and the sealing gas import of dry gas seal body and the outlet of system high-pressure tank are communicated, the leakage gas outlet of dry gas seal body and the inlet of leakage gas collection tank are communicated, the outlet of leakage gas collection tank is communicated with the inlet of emptying gas collection tank by air blower, the outlet of emptying gas collection tank is divided into two roads, one road is communicated with the isolation gas import of dry gas seal body and the inlet of compressor, the outlet of compressor is divided into two roads, one road is communicated with the hot side inlet of system pre-cooler, the other road is communicated with the inlet of low-temperature two-phase expander by cooler, the outlet of low-temperature two-phase expander is communicated with the inlet of system liquid storage tank, motor is connected with low-temperature two-phase expander and compressor, and the system can recover the working medium and energy of dry gas seal leakage device.

Description

Technical Field

[0001] The invention belongs to the technical field of supercritical carbon dioxide cycle power generation and relates to a dry gas seal near-zero leakage and working medium recovery system. Background Art

[0002] Supercritical carbon dioxide power generation technology has the advantages of high efficiency, small size, and fast peak-shaving speed. As a cutting-edge and revolutionary power generation technology, supercritical carbon dioxide cycle power generation technology has many advantages over the traditional steam Rankine cycle due to the working fluid itself and the cycle endowment. These advantages include a simple power generation system, small equipment size, compact layout, high thermoelectric conversion efficiency, wide heat source adaptability, good deep peak-shaving and rapid peak-shaving potential, and complete thermoelectric decoupling that allows thermoelectricity to be output in any proportion.

[0003] Dry gas seals are essential sealing devices for carbon dioxide compressors and turbines. Currently, their leakage rate is approximately 0.2% of the main flow rate. However, in some special industries or confined spaces, the leakage rate is required to be as low as 0.1% or even lower. Therefore, it is very necessary to study and design the working fluid recovery and energy recovery system of the dry gas seal leakage device. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a dry gas seal near-zero leakage and working fluid recovery system, which can recover the working fluid and energy of the dry gas seal leakage device.

[0005] To achieve the above-mentioned purpose, the dry gas seal near-zero leakage and working medium recovery system of the present invention includes a transfer device and a dry gas seal body, a system high-pressure tank, a leakage gas collecting tank, a blower, an emptying gas collecting tank, a compressor, a system precooler hot side inlet, a cooler, a low-temperature two-phase expander, a system liquid storage tank and a motor;

[0006] The sealing gas inlet of the transfer equipment and the dry gas sealing body is connected to the outlet of the system high-pressure tank, the leakage gas outlet of the transfer equipment and the dry gas sealing body is connected to the inlet of the leakage gas collecting tank, the outlet of the leakage gas collecting tank is connected to the inlet of the emptying gas collecting tank via a blower, the outlet of the emptying gas collecting tank is divided into two paths, one of which is connected to the isolation gas inlet of the transfer equipment and the dry gas sealing body, and the other is connected to the inlet of the compressor, the outlet of the compressor is divided into two paths, one of which is connected to the hot side inlet of the system precooler, and the other is connected to the inlet of the low-temperature two-phase expander via the cooler, the outlet of the low-temperature two-phase expander is connected to the inlet of the system liquid storage tank, and the motor is connected to the low-temperature two-phase expander and the compressor.

[0007] The motor is coaxially arranged with the low-temperature two-phase expander and the compressor.

[0008] The outlet of the compressor is connected to the inlet of the system pre-cooler hot side through a system pre-cooler hot side inlet valve.

[0009] The outlet of the low-temperature two-phase expander is connected to the inlet of the system liquid storage tank through a system liquid storage tank inlet valve.

[0010] When the main circulation system needs to supplement the working medium, the system pre-cooler hot side inlet valve is opened, and the system liquid storage tank inlet valve is closed.

[0011] The start-up condition of the air blower is that the working medium pressure in the leakage collection tank is greater than 1.2 times the local atmospheric pressure.

[0012] The shutdown condition of the air blower is that the working medium pressure in the leakage collection tank is less than 0.8 times the local atmospheric pressure.

[0013] The design pressure of the compressor inlet is 0.3-0.5 MPa, and the inlet temperature is 20-40 DEG C.

[0014] The start-up condition of the compressor is that the working medium pressure in the emptying collection tank is greater than 0.5 MPa.

[0015] The shutdown condition of the compressor is that the working medium pressure in the emptying collection tank is less than 0.45 MPa.

[0016] The present application has the following beneficial effects:

[0017] The dry gas seal near-zero leakage and working medium recovery system in the specific operation, through the leakage collection tank collects the leakage gas, then through the air blower pressurization, and then sent to the emptying collection tank, the working medium in the emptying collection tank is divided into two ways, one way is sent into the turbine equipment and dry gas seal body as isolation gas, the other way enters into the compressor, and then recycled through the compressor compression, to realize the recovery of the working medium and energy of the dry gas seal leakage device, the structure is simple, the operation is convenient, the practicality is extremely strong, the system turbine leakage rate can be reduced to the level of one ten millionth or even lower, and the energy utilization rate of the system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structural schematic view of the present application.

[0019] 1 is turbine equipment and dry gas seal body, 2 is sealing gas inlet, 3 is isolation gas inlet, 4 is leakage gas outlet, 5 is leakage collection tank, 6 is air blower, 7 is emptying collection tank, 8 is compressor, 9 is motor, 10 is low-temperature two-phase expander, 11 is cooler, 12 is system pre-cooler hot side inlet valve, 13 is system liquid storage tank inlet valve. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0021] The accompanying drawings illustrate schematic diagrams of the structures of the disclosed embodiments of the present invention. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0022] refer to Figure 1 The dry gas seal near-zero leakage and working medium recovery system of the present invention includes a transfer device and a dry gas seal body 1, a sealing gas inlet 2, an isolation gas inlet 3, a leakage gas outlet 4, a leakage gas collecting tank 5, a blower 6, an emptying gas collecting tank 7, a compressor 8, an electric motor 9, a low-temperature two-phase expander 10, a cooler 11, a system precooler hot side inlet valve 12 and a system liquid storage tank inlet valve 13;

[0023] The sealing gas inlet 2 of the converter equipment and the dry gas sealing body 1 is connected to the outlet of the system high-pressure tank, and the leakage gas outlet of the converter equipment and the dry gas sealing body 1 is connected to the inlet of the leakage gas collecting tank 5. The outlet of the leakage gas collecting tank 5 is connected to the inlet of the emptying gas collecting tank 7 via the blower 6. The outlet of the emptying gas collecting tank 7 is divided into two paths, one of which is connected to the isolation gas inlet 3 of the converter equipment and the dry gas sealing body 1, and the other is connected to the inlet of the compressor 8. The outlet of the compressor 8 is divided into two paths, one of which is connected to the hot side inlet of the system precooler through the hot side inlet valve 12 of the system precooler, and the other is connected to the inlet of the low-temperature two-phase expander 10 through the cooler 11. The outlet of the low-temperature two-phase expander 10 is connected to the inlet of the system liquid storage tank through the system liquid storage tank inlet valve 13. The low-temperature two-phase expander 10, the motor 9 and the compressor 8 are coaxially arranged.

[0024] Furthermore, the emptying gas collecting tank 7 is also connected to the system high-pressure emptying.

[0025] The specific working process of the present invention is:

[0026] During the dry gas seal leakage recovery process, the high-pressure working fluid output by the system high-pressure tank is injected into the converter equipment and the dry gas seal body 1 through the sealing gas inlet 2, and the low-pressure isolation gas is injected through the isolation gas inlet 3. The dry gas seal leakage gas is discharged through the leakage gas outlet 4 and enters the leakage gas collecting tank 5. The gas output by the leakage gas collecting tank 5 enters the emptying gas collecting tank 7 through the blower 6. Among them, the gas output by the emptying gas collecting tank 7 is divided into two paths, one of which is sent to the converter equipment and the dry gas seal body 1 as isolation gas, and the other enters the compressor 8 for compression. Among them, the compressed gas output by the compressor 8 is divided into two paths, one of which enters the low-temperature two-phase expander 10 to do work, and then enters the system liquid storage tank, and the other enters the hot side inlet of the system precooler.

[0027] It should be noted that the pressure of the working fluid at the sealing gas inlet 2 is 15MPa-30MPa and the temperature is 100°C-150°C. The pressure of the working fluid at the leakage gas outlet 4 is 0.1MPa and the temperature is 20°C-40°C.

[0028] The function of the leakage gas collecting tank 5 is to collect the dry gas seal leakage gas and keep the inlet pressure of the blower 6 stable; the function of the blower 6 is to increase the pressure of the working fluid in the emptied gas collecting tank 7 to 0.3~0.5MPa to meet the gas usage requirements of the isolation gas; the blower 6 operates at a variable speed, and the starting condition is that the working fluid pressure in the leakage gas collecting tank 5 is greater than 1.2 times the local atmospheric pressure, and the shutdown condition is that the working fluid pressure in the leakage gas collecting tank 5 is less than 0.8 times the local atmospheric pressure.

[0029] One of the functions of the emptying gas collecting tank 7 is to collect and store the low-pressure working fluid output by the blower 6, maintain the outlet pressure of the blower 6 stable, and at the same time collect and recover the high-pressure emptying working fluid from other points in the system; the pressure of the working fluid in the emptying gas collecting tank 7 is 0.3~0.5MPa, and its outside does not need thermal insulation cotton, it is directly exposed to the atmosphere and dissipates heat outward, and the temperature in the emptying gas collecting tank 7 is maintained the same as the ambient temperature; the gas output by the emptying gas collecting tank 7 is led out to connect to the isolation gas inlet 3 on one side to meet the gas requirements of the isolation gas, and the other side is connected to the compressor 8.

[0030] The design pressure of the compressor 8 inlet is 0.3-0.5MPa, the inlet temperature is 20℃-40℃, the outlet pressure is 8MPa, and the outlet temperature is 270℃-290℃; when the main circulation system needs to make up the working fluid, the system precooler hot side inlet valve 12 is opened, the system liquid storage tank inlet valve 13 is closed, and the working fluid output by the compressor 8 is directly merged into the system precooler hot side inlet; when the main circulation system does not need to make up the working fluid, the system precooler hot side inlet valve 12 is closed, the system liquid storage tank inlet valve 13 is opened, the working fluid output by the compressor 8 is cooled to 20℃-40℃ by the cooler 11, and then enters the low-temperature two-phase expander 10 for expansion, and is cooled and depressurized to a gas-liquid two-phase working fluid of -15℃--20℃ and 2MPa, and then is injected into the system liquid storage tank; one of the functions of the low-temperature two-phase expander 10 is to recover expansion work, and the other function is to cool and depressurize the high-pressure working fluid to a low-temperature and low-pressure two-phase working fluid, and inject it into the system liquid storage tank.

[0031] The cantilevered arms of the low-temperature two-phase expander 10 and compressor 8 are mounted on either end of the motor 9. The three components rotate coaxially and at the same speed, enabling variable speed operation. Compressor 8 is activated when the working fluid pressure within the evacuated gas collecting tank 7 exceeds 0.5 MPa, and is shut down when the working fluid pressure within the evacuated gas collecting tank 7 falls below 0.45 MPa.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A dry gas seal near-zero leakage and working fluid recovery system, characterized in that: It includes a transfer device and a dry gas seal body (1), a system high-pressure tank, a leaking gas collecting tank (5), a blower (6), an emptying gas collecting tank (7), a compressor (8), a system precooler hot side inlet, a cooler (11), a low-temperature two-phase expander (10), a system liquid storage tank and a motor (9); The sealing gas inlet (2) of the converter device and the dry gas sealing body (1) is connected to the outlet of the system high-pressure tank, the leakage gas outlet of the converter device and the dry gas sealing body (1) is connected to the inlet of the leakage gas collecting tank (5), the outlet of the leakage gas collecting tank (5) is connected to the inlet of the emptying gas collecting tank (7) via the blower (6), the outlet of the emptying gas collecting tank (7) is divided into two paths, one of which is connected to the isolation gas inlet (3) of the converter device and the dry gas sealing body (1), and the other is connected to the inlet of the compressor (8), the outlet of the compressor (8) is divided into two paths, one of which is connected to the hot side inlet of the system precooler, and the other is connected to the inlet of the low-temperature two-phase expander (10) via the cooler (11), the outlet of the low-temperature two-phase expander (10) is connected to the inlet of the system liquid storage tank, and the motor (9) is connected to the low-temperature two-phase expander (10) and the compressor (8); The outlet of the compressor (8) is connected to the hot side inlet of the system precooler through the hot side inlet valve (12) of the system precooler.

2. The dry gas seal near-zero leakage and working medium recovery system according to claim 1 is characterized in that: The electric motor (9) is coaxially arranged with the low-temperature two-phase expander (10) and the compressor (8).

3. The dry gas seal near-zero leakage and working medium recovery system according to claim 1 is characterized in that: The outlet of the low-temperature two-phase expander (10) is connected to the inlet of the system liquid storage tank via the system liquid storage tank inlet valve (13).

4. The dry gas seal near-zero leakage and working medium recovery system according to claim 3 is characterized in that: When the main circulation system needs to replenish the working fluid, the hot side inlet valve (12) of the system precooler is opened and the inlet valve (13) of the system liquid storage tank is closed.

5. The dry gas seal near-zero leakage and working medium recovery system according to claim 1, characterized in that: The starting condition of the blower (6) is: the working fluid pressure in the leaking gas collecting tank (5) is greater than 1.2 times the local atmospheric pressure; The stop condition of the blower (6) is: the working fluid pressure in the leaking gas collecting tank (5) is less than 0.8 times the local atmospheric pressure.

6. The dry gas seal near-zero leakage and working medium recovery system according to claim 1, characterized in that: The design pressure of the compressor (8) inlet is 0.3-0.5 MPa, and the inlet temperature is 20°C-40°C.

7. The dry gas seal near-zero leakage and working medium recovery system according to claim 1, characterized in that: The starting conditions of the compressor (8) are: the working medium pressure in the evacuated gas collecting tank (7) is greater than 0.5 MPa; The shutdown condition of the compressor (8) is: the working medium pressure in the evacuated gas collecting tank (7) is less than 0.45 MPa.

Images