Flash steam energy recovery system and coal water slurry gasification furnace system

Abstract

The utility model discloses a flash steam energy recovery system and a coal water slurry gasifier system.The flash steam energy recovery system comprises a non-condensable gas separation unit, a gas-liquid separation tank, a power generation unit and a recovery unit, and an inlet of the gas-liquid separation tank communicates with a liquid outlet of the non-condensable gas separation unit; and the power generation unit is communicated with the gas outlet of the gas-liquid separation tank and the recovery unit. The non-condensable gas is separated from the initial black water discharged from the gasification furnace and the washing tower through the non-condensable gas separation unit to form the secondary black water, the saturated steam is flashed from the secondary black water through the gas-liquid separation tank, and the pressure potential energy of the saturated steam is used for acting to drive the power generation unit to generate power. The low-temperature and low-pressure dead steam obtained after acting is introduced into a recovery unit to be recovered; according to the method, the non-condensable gas in the initial black water is separated and then is subjected to flash evaporation power generation, so that the non-condensable gas can be recycled, the situation that the non-condensable gas participates in power generation to lower the power generation efficiency can be avoided, and the energy recovery efficiency of the initial black water is remarkably improved.

Description

Technical Field

[0001] The present application relates to the field of energy recovery technology, and in particular to a flash steam energy recovery system and a water-coal slurry gasification furnace system. Background Art

[0002] Coal-water slurry gasification is widely used in the chemical industry. During the coal-water slurry gasification process, the black water produced by scrubbing and cooling is treated through high-flash, low-flash, and two-stage vacuum flash evaporation to reduce the temperature, recover heat, concentrate the black water, and desorb acidic gases. The step-by-step flash evaporation of the high-temperature black water produces large amounts of saturated steam at varying pressures. This saturated steam contains large amounts of dust, corrosive media, combustible gases, and other non-condensable gases, making it difficult to recycle. Currently, with the exception of the low-flash steam, which is entirely used for deoxidation and heating, the remaining flash steam is largely not effectively recycled, resulting in significant energy losses. Summary of the Invention

[0003] The purpose of this application is to overcome the shortcomings of low flash steam recovery efficiency in the prior art and to provide a flash steam energy recovery system and a water-coal slurry gasification furnace system with higher energy recovery efficiency.

[0004] The technical solution of the present application provides a flash gas energy recovery system, comprising a non-condensable gas separation unit, a gas-liquid separation tank, a power generation unit and a recovery unit;

[0005] The non-condensable gas separation unit is used to receive the initial black water discharged from the gasifier and the scrubber and separate the non-condensable gas. The inlet of the gas-liquid separation tank is connected to the liquid outlet of the non-condensable gas separation unit. The gas-liquid separation tank is used to receive the secondary black water after the non-condensable gas is separated and flash evaporate saturated steam.

[0006] The power generation unit is connected to the gas outlet of the gas-liquid separation tank and the recovery unit. The saturated steam drives the power generation unit to generate electricity to be converted into low-temperature and low-pressure exhaust steam and then introduced into the recovery unit. The liquid outlet of the gas-liquid separation tank is connected to the front-end reaction system.

[0007] Furthermore, the non-condensable gas separation unit includes a non-condensable gas separation tank and a non-condensable gas compression device;

[0008] The inlet of the non-condensable gas separation tank is used to receive initial black water, the inlet of the non-condensable gas compression device is connected to the gas outlet of the non-condensable gas separation tank, the outlet of the non-condensable gas compression device is used to connect to the conversion reaction system to send the compressed non-condensable gas into the conversion reaction system, the liquid outlet of the non-condensable gas separation tank is connected to the front-end reaction system, and the liquid outlet of the non-condensable gas separation tank is connected to the inlet of the gas-liquid separation tank.

[0009] Furthermore, the non-condensable gas compression device includes a compressor and an electric motor;

[0010] The gas inlet of the compressor is communicated with the gas outlet of the non-condensable gas separation tank, the gas outlet of the compressor is communicated with the shift reaction system, and the motor is connected to the compressor for driving the compressor to work.

[0011] Furthermore, the compressor is a multi-stage isothermal compressor.

[0012] Furthermore, the compressor pressurizes the non-condensable gas to 6±0.1 MPa.

[0013] Furthermore, the pressure of the non-condensable gas separation tank is controlled between 2.4±0.1 MPa.

[0014] Furthermore, the power generation unit includes an expander and a generator, and the expander is provided with a high-pressure gas inlet, a low-pressure gas outlet and a power output end;

[0015] The high-pressure gas inlet is communicated with the gas outlet of the gas-liquid separation tank, the low-pressure gas outlet is communicated with the recovery unit, and the generator is connected to the power output end of the expander.

[0016] Furthermore, the recovery unit includes a heat exchanger and a liquid storage tank;

[0017] The inlet of the heat exchanger is communicated with the low-pressure gas outlet, the inlet of the liquid storage tank is communicated with the outlet of the heat exchanger, and the outlet of the liquid storage tank is communicated with the front-end reaction system.

[0018] Furthermore, the heat exchanger is a water cooler or a fluid heater.

[0019] The technical solution of the present application also provides a water-coal slurry gasification furnace system, including the flash steam energy recovery system as described above.

[0020] The above technical solution has the following beneficial effects:

[0021] The present application first separates the non-condensable gas from the initial black water discharged from the gasifier and the washing tower through a non-condensable gas separation unit to form secondary black water, then flashes saturated steam from the secondary black water through a gas-liquid separation tank, uses the pressure potential energy of the saturated steam to drive the power generation unit to generate electricity, and then passes the low-temperature and low-pressure exhaust steam after the work into the recovery unit for recovery; first separating the non-condensable gas in the initial black water and then flashing it to generate electricity can not only realize the recycling of the non-condensable gas, but also avoid the non-condensable gas participating in power generation and lowering the power generation efficiency, thereby significantly improving the energy recovery efficiency of the initial black water. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The disclosure of this application will become easier to understand with reference to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. In the drawings:

[0023] Figure 1 It is a structural diagram of a flash steam energy recovery system in one embodiment of the present application.

[0024] Reference table of accompanying symbols:

[0025] Non-condensable gas separation unit 01: non-condensable gas separation tank 11, compressor 12, motor 13;

[0026] Gas-liquid separation tank 02;

[0027] Power generation unit 03: expander 31, generator 32;

[0028] Recovery unit 04: heat exchanger 41, liquid storage tank 42. DETAILED DESCRIPTION

[0029] The specific implementation of this application is further described below with reference to the accompanying drawings.

[0030] It is easy to understand that according to the technical solution of this application, a variety of structural methods and implementation methods can be replaced with each other by those skilled in the art without changing the essential spirit of this application. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of this application and should not be regarded as the entire application or as a limitation or restriction of the technical solution of the application.

[0031] In this specification, directional terms such as "up," "down," "left," "right," "front," "back," "front," "back," "top," and "bottom" are defined relative to the configurations shown in the accompanying drawings. These terms are relative and may vary depending on the device's location or usage. Therefore, these and other directional terms should not be construed as restrictive. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0033] The flash gas energy recovery system in the embodiment of the present application is as follows: Figure 1 As shown, it includes a non-condensable gas separation unit 01, a gas-liquid separation tank 02, a power generation unit 03 and a recovery unit 04;

[0034] The non-condensable gas separation unit 01 is used to receive the initial black water discharged from the gasifier and the scrubber and separate the non-condensable gas. The inlet of the gas-liquid separation tank 02 is connected to the liquid outlet of the non-condensable gas separation unit 01. The gas-liquid separation tank 02 is used to receive the secondary black water after the non-condensable gas is separated and flash evaporate saturated steam.

[0035] The power generation unit 03 is connected to the gas outlet of the gas-liquid separation tank 02 and the recovery unit 04. The saturated steam drives the power generation unit 03 to generate electricity to be converted into low-temperature and low-pressure exhaust steam and then introduced into the recovery unit 04. The liquid outlet of the gas-liquid separation tank 02 is connected to the front-end reaction system.

[0036] Specifically, the high-temperature, high-pressure initial black water discharged from the gasifier and scrubber first flows into the non-condensable gas separation unit 01, where it is depressurized and the non-condensable gas is separated to form secondary black water. In the water-coal slurry gasifier system, the primary components of non-condensable gas are CO, H₂, and CO₂. The separated non-condensable gas is essentially water-free and can be recycled. The secondary black water then flows from the liquid outlet of the non-condensable gas separation unit 01 into the gas-liquid separator tank 02, where it undergoes further pressure reduction and flash evaporation to produce saturated steam. The saturated steam is then passed from the gas outlet of the gas-liquid separator tank 02 to the power generation unit 03, where the pressure potential energy of the saturated steam is used to perform work, ultimately converting it into electrical energy. After performing work, the saturated steam is converted into low-temperature, low-pressure exhaust steam, which is then passed to the recovery unit 04 to recover the remaining energy and can be returned to the front-end reaction system for recycling. Simultaneously, the remaining condensate in the gas-liquid separator tank 02 is also returned to the front-end reaction system through the liquid outlet for recycling.

[0037] In the embodiment of the present application, the non-condensable gas in the initial black water is first separated and then flash evaporation is performed to generate electricity, which can not only realize the recycling of the non-condensable gas, but also avoid the non-condensable gas from participating in power generation and lowering the power generation efficiency, thereby significantly improving the energy recovery efficiency of the initial black water.

[0038] In one embodiment, the non-condensable gas separation unit 01 includes a non-condensable gas separation tank 11 and a non-condensable gas compression device;

[0039] The inlet of the non-condensable gas separation tank 11 is used to receive the initial black water, the inlet of the non-condensable gas compression device is connected to the gas outlet of the non-condensable gas separation tank 11, the outlet of the non-condensable gas compression device is used to connect to the transformation reaction system to send the compressed non-condensable gas into the transformation reaction system, and the liquid outlet of the non-condensable gas separation tank 11 is connected to the inlet of the gas-liquid separation tank 02.

[0040] In the embodiment of the present application, the non-condensable gas separation unit 01 uses the non-condensable gas separation tank 11 to reduce the pressure of the initial black water. The non-condensable gas after depressurization is discharged from the gas outlet at the top of the non-condensable gas separation tank 11 to the non-condensable gas compression device. The non-condensable gas compression device compresses and pressurizes the non-condensable gas after depressurization and sends it into the conversion reaction system to participate in the conversion reaction, thereby realizing the recovery and utilization of the non-condensable gas in the initial black water; at the same time, the secondary black water after the non-condensable gas is separated flows into the gas-liquid separation tank 02 from the liquid outlet at the bottom of the non-condensable gas separation tank 11 to continue to reduce the pressure and recover.

[0041] In one embodiment, the non-condensable gas compression device includes a compressor 12 and a motor 13;

[0042] The gas inlet of the compressor 12 is connected to the gas outlet of the non-condensable gas separation tank 11 , the gas outlet of the compressor 12 is connected to the shift reaction system, and the motor 13 is connected to the compressor 12 for driving the compressor 12 to work.

[0043] Preferably, a multi-stage isothermal compressor is used as compressor 12. Compressor 12 is driven by motor 13. Non-condensable gas enters compressor 12 through its gas inlet. Compressor 12 compresses the non-condensable gas to a pressure close to that of the shift reaction system. The gas is then fed into the shift reaction system through its gas outlet to participate in the shift reaction, thereby recycling the non-condensable gas.

[0044] For example, the initial black water discharged from the gasifier and scrubber is at a pressure of approximately 6±0.1 MPa. This initial black water is depressurized in the non-condensable gas separator 11, where the pressure is controlled between 2.4±0.1 MPa to separate the non-condensable gas from the initial black water. The separated non-condensable gas is then further pressurized by compressor 12 to a reaction system pressure of 6±0.1 MPa before being recycled into the shift reaction system to continue the reaction, thus avoiding affecting the pressure within the reaction system.

[0045] In one embodiment, the power generation unit 03 includes an expander 31 and a generator 32, and the expander 31 is provided with a high-pressure gas inlet, a low-pressure gas outlet and a power output end;

[0046] The high-pressure gas inlet is connected to the gas outlet of the gas-liquid separation tank 02 , the low-pressure gas outlet is connected to the recovery unit 04 , and the generator 32 is connected to the power output end of the expander 31 .

[0047] In the embodiment of the present application, the expander 31 utilizes the pressure of saturated steam to convert the pressure potential energy of saturated steam into mechanical energy and outputs it to the generator 32. The generator 32 converts the mechanical energy into electrical energy, thereby realizing the recovery and utilization of the pressure potential energy of saturated steam.

[0048] In one embodiment, the recovery unit 04 includes a heat exchanger 41 and a liquid storage tank 42;

[0049] The inlet of the heat exchanger 41 is communicated with the low-pressure gas outlet, the inlet of the liquid storage tank 42 is communicated with the outlet of the heat exchanger 41 , and the outlet of the liquid storage tank 42 is communicated with the front-end reaction system.

[0050] Specifically, after saturated steam passes through power generation unit 03 and performs work, it becomes low-temperature, low-pressure exhaust steam. The energy in the low-temperature, low-pressure exhaust steam is not fully recovered, and its temperature is still relatively high. Recovery unit 04 includes a heat exchanger 41 to further recover and condense the low-temperature, low-pressure exhaust steam into condensate. Heat exchanger 41 can be a water cooler or fluid heater, utilizing the temperature of the low-temperature, low-pressure exhaust steam to heat water or other fluids. The condensed low-temperature, low-pressure exhaust steam then flows into liquid storage tank 42 and is recycled back to the front-end reaction system to continue participating in the reaction.

[0051] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0052] The water-coal slurry gasification furnace system in the embodiment of the present application includes the flash steam energy recovery system provided in the aforementioned embodiment. Since the water-coal slurry gasification furnace system in the embodiment of the present application has the same advantages as the flash steam energy recovery system provided in the aforementioned embodiment, they will not be repeated here.

[0053] The above description is merely the principle and preferred embodiments of the present application. It should be noted that, for those skilled in the art, implementation methods obtained by appropriately combining the technical solutions disclosed in different embodiments are also included in the technical scope of the present invention. Based on the principles of the present application, several other variations can be made and should also be considered as the scope of protection of the present application.

Claims

1. A flash gas energy recovery system, characterized in that: It includes non-condensable gas separation unit, gas-liquid separation tank, power generation unit and recovery unit; The non-condensable gas separation unit is used to receive the initial black water discharged from the gasifier and the scrubber and separate the non-condensable gas. The inlet of the gas-liquid separation tank is connected to the liquid outlet of the non-condensable gas separation unit. The gas-liquid separation tank is used to receive the secondary black water after the non-condensable gas is separated and flash evaporate saturated steam. The power generation unit is connected to the gas outlet of the gas-liquid separation tank and the recovery unit. The saturated steam drives the power generation unit to generate electricity to be converted into low-temperature and low-pressure exhaust steam and then introduced into the recovery unit. The liquid outlet of the gas-liquid separation tank is connected to the front-end reaction system.

2. The flash gas energy recovery system according to claim 1, characterized in that: The non-condensable gas separation unit includes a non-condensable gas separation tank and a non-condensable gas compression device; The inlet of the non-condensable gas separation tank is used to receive initial black water, the inlet of the non-condensable gas compression device is connected to the gas outlet of the non-condensable gas separation tank, the outlet of the non-condensable gas compression device is used to connect to the conversion reaction system to send the compressed non-condensable gas into the conversion reaction system, and the liquid outlet of the non-condensable gas separation tank is connected to the inlet of the gas-liquid separation tank.

3. The flash gas energy recovery system according to claim 2, characterized in that: The non-condensable gas compression device includes a compressor and an electric motor; The gas inlet of the compressor is communicated with the gas outlet of the non-condensable gas separation tank, the gas outlet of the compressor is communicated with the shift reaction system, and the motor is connected to the compressor for driving the compressor to work.

4. The flash gas energy recovery system according to claim 3, characterized in that: The compressor is a multi-stage isothermal compressor.

5. The flash gas energy recovery system according to claim 3, characterized in that: The compressor pressurizes the non-condensable gas to 6±0.1 MPa.

6. The flash gas energy recovery system according to claim 2, characterized in that: The pressure of the non-condensable gas separation tank is controlled between 2.4±0.1 MPa.

7. The flash gas energy recovery system according to any one of claims 1 to 6, characterized in that: The power generation unit includes an expander and a generator, wherein the expander is provided with a high-pressure gas inlet, a low-pressure gas outlet and a power output end; The high-pressure gas inlet is communicated with the gas outlet of the gas-liquid separation tank, the low-pressure gas outlet is communicated with the recovery unit, and the generator is connected to the power output end of the expander.

8. The flash gas energy recovery system according to claim 7, characterized in that: The recovery unit includes a heat exchanger and a liquid storage tank; The inlet of the heat exchanger is communicated with the low-pressure gas outlet, the inlet of the liquid storage tank is communicated with the outlet of the heat exchanger, and the outlet of the liquid storage tank is communicated with the front-end reaction system.

9. The flash gas energy recovery system according to claim 8, characterized in that: The heat exchanger is a water cooler or a fluid heater.

10. A water-coal slurry gasification furnace system, characterized in that: The method comprises the flash steam energy recovery system according to any one of claims 1 to 9.

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