Gasification black water waste heat recovery steam production device

Abstract

The utility model belongs to the technical field of coal chemical industry, and particularly discloses a gasified black water waste heat recovery steam making device which comprises a waste heat recovery system, a heating medium water circulation system, a steam making system and a low-pressure steam compression system. The waste heat recovery system comprises a low-pressure flash tank, a vacuum flash tank and a black water heat exchanger; the heat medium water circulation system comprises a heat medium water circulation pump and an absorption heat pump, the heat medium water circulation pump is used for conveying heat medium water in the black water heat exchanger to the absorption heat pump, and then the heat medium water is cooled by the absorption heat pump and conveyed back to the black water heat exchanger; the steam preparation system comprises a deaerator device, a deaeration water pump and a steam buffer tank, the deaerator device is used for deaerating demineralized water, and the steam buffer tank is used for carrying out gas-liquid separation; the low-pressure steam compression system comprises a steam compressor, and a steam inlet of the steam compressor is connected with a steam outlet of the steam buffer tank.

Description

Technical Field

[0001] The utility model relates to the technical field of coal chemical industry, in particular to a steam production device for recovering waste heat from gasified black water. Background Art

[0002] With the joint release of the "Notice on Promoting the Healthy Development of the Modern Coal Chemical Industry" by six ministries including the National Development and Reform Commission and the Ministry of Industry and Information Technology, it is clearly proposed to strengthen the clean and efficient use of coal, promote the high-end, diversified and low-carbon development of the modern coal chemical industry, accelerate the promotion and application of green and low-carbon technologies and equipment, guide existing modern coal chemical enterprises to implement energy-saving, carbon reduction, water-saving and pollution reduction transformation and upgrading, strengthen refined management of the entire process, improve resource and energy utilization efficiency, strengthen the leading and constraining role of energy efficiency, water efficiency and pollutant emission standards, and steadily improve the green and low-carbon development level of modern coal chemical industry.

[0003] During the cooling and scrubbing process of high-temperature coal gas in coal chemical gasification units, vaporized black water at 230-260°C is generated. This black water is typically cooled to approximately 130-140°C through high- and low-pressure flash evaporation. The steam generated by flash evaporation is used as a heat source for other processes, effectively utilizing energy. After low-pressure flash evaporation, the 130-140°C vaporized black water is then cooled to 70-80°C through vacuum flash evaporation. The low-pressure exhaust steam from vacuum flash evaporation is of low quality and cannot be used directly. It is typically condensed with circulating cooling water and discharged into the black water tank, resulting in a waste of energy and water resources. Summary of the Invention

[0004] The purpose of the present invention is to provide a steam-making device for recovering waste heat from gasified black water, so as to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above objectives, the present invention provides the following technical solutions: a device for recovering waste heat from gasified black water to produce steam, comprising a waste heat recovery system, a heat medium water circulation system, a steam production system and a low-pressure steam compression system.

[0006] The waste heat recovery system includes a low-pressure flash tank, a vacuum flash tank, and a black water heat exchanger. The low-pressure flash tank and vacuum flash tank are connected to the black water inlet and outlet of the black water heat exchanger, respectively. The black water heat exchanger unit utilizes a fully welded straight-channel plate structure, with heat transfer elements made of 2205 duplex stainless steel. This design offers advantages such as anti-clogging, corrosion resistance, wear resistance, high heat transfer efficiency, and reduced resistance.

[0007] The heat transfer water circulation system includes a heat transfer water circulation pump and an absorption heat pump. The heat transfer water circulation pump is connected to the heat transfer water outlet of the black water heat exchanger and the heat transfer water inlet of the absorption heat pump, respectively. The heat transfer water outlet of the absorption heat pump is connected to the heat transfer water inlet of the black water heat exchanger. The heat transfer water circulation pump is used to transfer heat transfer water from the black water heat exchanger to the absorption heat pump, where it is then cooled and returned to the black water heat exchanger.

[0008] The steam production system includes a deaerator, a deoxygenated water pump, and a steam buffer tank. The deoxygenated water pump is connected to the deoxygenated water outlet of the deaerator and the deoxygenated water inlet of the absorption heat pump, while the steam buffer tank is connected to the deoxygenated water outlet of the absorption heat pump. The deaerator is used to deoxygenate the deoxygenated water, and the steam buffer tank is used to separate gas and liquid.

[0009] The low-pressure steam compression system includes a steam compressor, the steam inlet of the steam compressor is connected to the steam outlet of the steam buffer tank. The steam compressor is used to compress steam

[0010] As a preferred embodiment of the present invention, a flash tank liquid level control valve is connected between the black water heat exchanger and the vacuum flash tank, and the liquid level control valve is provided to control the liquid level of the black water after heat exchange. The black water heat exchanger is a non-filtered, full-flux black water heat exchanger.

[0011] As a preferred embodiment of the present invention, a constant pressure water replenishment device is connected between the black water heat exchanger and the heat medium water circulation pump. The constant pressure water replenishment device is used to ensure the pressure of the circulation system and prevent the heat medium water from losing pressure and gasifying.

[0012] As a preferred embodiment of the present invention, a heat transfer water flow control valve is provided between the heat transfer water circulation pump and the absorption heat pump, and a heat transfer water return control valve is connected between the heat transfer water inlet and the heat transfer water outlet of the absorption heat pump. The heat transfer water flow control valve is used to control the flow of the heat transfer water, and the heat transfer water return control valve can control the heat transfer water to return to the absorption heat pump.

[0013] As a preferred embodiment of the present invention, the absorption heat pump is connected to a circulating cooling water device, which is used to ensure the energy balance of the system.

[0014] As a preferred embodiment of the present invention, the deaerator device is provided with a deaerator liquid level control valve at the desalted water inlet, and a deaerator pressure control valve is provided on the deaerator device. The deaerator liquid level control valve is used to control the liquid level flow of the desalted water, and the deaerator pressure control valve is used to control the pressure within the deaerator device.

[0015] As a preferred embodiment of the present invention, a compressor return valve is connected between the steam inlet and the steam outlet of the steam compressor, and the compressor return valve can return the steam in the steam outlet of the steam compressor to the steam compressor for compression.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] In summary, this device recovers waste heat from the blackwater at the outlet of the low-pressure flash tank of the gasification unit, reducing the amount of flash steam in the vacuum flash tank. It also reduces the amount of circulating water used to cool the exhaust steam from the original vacuum flash tank top, thereby reducing energy waste. The recovered energy is used to produce medium-pressure steam for various heat users, achieving energy recycling and reducing carbon emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the utility model process.

[0019] In the figure: 1. Low-pressure flash tank; 2. Vacuum flash tank; 3. Black water heat exchanger; 4. Heat medium water circulation pump; 5. Constant pressure water make-up device; 6. Absorption heat pump; 7. Steam buffer tank; 8. Steam compressor; 9. Deaerator device; 10. Deaerator water pump; 11. Circulating cooling water device; 12. Flash tank liquid level control valve; 13. Heat medium water flow control valve; 14. Heat medium water return control valve; 15. Compressor return valve; 16. Deaerator pressure control valve; 17. Deaerator liquid level control valve. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0022] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0023] See also Figure 1 The utility model provides a technical solution: a steam production device for recovering waste heat from gasified black water, including a waste heat recovery system, a heat medium water circulation system, a steam production system and a low-pressure steam compression system.

[0024] Furthermore, the waste heat recovery system includes a low-pressure flash tank 1, a vacuum flash tank 2, and a black water heat exchanger 3. The low-pressure flash tank 1 and the vacuum flash tank 2 are respectively connected to the black water inlet and black water outlet of the black water heat exchanger 3. The black water heat exchange unit adopts a fully welded straight channel plate structure, and the heat transfer elements are made of 2205 duplex stainless steel, which has the advantages of anti-clogging, corrosion resistance, wear resistance, high heat transfer efficiency, and reduced resistance.

[0025] Furthermore, the heat medium water circulation system includes a heat medium water circulation pump 4 and an absorption heat pump 6. The heat medium water circulation pump 4 is connected to the heat medium water outlet of the black water heat exchanger 3 and the heat medium water inlet of the absorption heat pump 6, respectively. The heat medium water outlet of the absorption heat pump 6 is connected to the heat medium water inlet of the black water heat exchanger 3. The heat medium water circulation pump 4 is used to send the heat medium water in the black water heat exchanger 3 to the absorption heat pump 6, which then cools the heat medium water and sends it back to the black water heat exchanger 3.

[0026] Furthermore, the steam production system includes a deaerator device 9, a deoxygenated water pump 10, and a steam buffer tank 7. The deoxygenated water pump 10 is connected to the deoxygenated water outlet of the deaerator device 9 and the deoxygenated water inlet of the absorption heat pump 6. The steam buffer tank 7 is connected to the deoxygenated water outlet of the absorption heat pump 6. The deaerator device 9 is used to deoxygenate the desalted water, and the steam buffer tank 7 is used to perform gas-liquid separation.

[0027] Furthermore, the low-pressure steam compression system includes a steam compressor 8, and a steam inlet of the steam compressor 8 is connected to a steam outlet of the steam buffer tank 7. The steam compressor 8 is used to compress steam.

[0028] Furthermore, a flash tank level control valve 12 is connected between the black water heat exchanger 3 and the vacuum flash tank 2. The level control valve is used to control the level of the black water after heat exchange. The black water heat exchanger 3 is a non-filtered, full-flux black water heat exchanger 3.

[0029] Furthermore, a constant pressure water replenishing device 5 is connected between the black water heat exchanger 3 and the heat medium water circulation pump 4. The constant pressure water replenishing device 5 is used to ensure the pressure of the circulation system and prevent the heat medium water from losing pressure and gasifying.

[0030] Furthermore, a heat medium water flow control valve 13 is provided between the heat medium water circulation pump 4 and the absorption heat pump 6, and a heat medium water return control valve 14 is connected between the heat medium water inlet and the heat medium water outlet of the absorption heat pump 6. The heat medium water flow control valve 13 is used to control the flow of the heat medium water, and the heat medium water return control valve 14 can control the heat medium water to return to the absorption heat pump 6.

[0031] Furthermore, the absorption heat pump 6 is connected to a circulating cooling water device 11, which is used to ensure the energy balance of the system.

[0032] Furthermore, a deaerator liquid level control valve 17 is provided at the desalted water inlet of the deaerator device 9, and a deaerator pressure control valve 16 is provided on the deaerator device 9. The deaerator liquid level control valve 17 is used to control the liquid level flow of the desalted water, and the deaerator pressure control valve 16 is used to control the pressure within the deaerator device 9.

[0033] Furthermore, a compressor return valve 15 is connected between the steam inlet and the steam outlet of the steam compressor 8. The compressor return valve 15 can return the steam in the steam outlet of the steam compressor 8 to the steam compressor 8 for compression.

[0034] In summary, the specific process of using this device is as follows:

[0035] Waste heat recovery

[0036] Black water at approximately 145°C from the bottom of the coal gasification unit's low-pressure flash tank 1 is fed to the hot side of black water heat exchanger 3. After exchanging heat with the heat transfer medium on the cold side of the black water heat exchanger 3, it is cooled to approximately 70°C. The water then passes through the low-pressure flash tank level control valve 12 and returns to vacuum flash tank 2, recovering the black water's waste heat. The black water heat exchanger unit utilizes a fully welded straight-channel plate structure with heat transfer elements made of 2205 duplex stainless steel, offering advantages such as anti-clogging, corrosion-resistant, and wear-resistant properties, high heat transfer efficiency, and reduced resistance.

[0037] Heat transfer water cycle

[0038] The heat transfer water on the cold side of black water heat exchanger 3 draws heat and is heated to 125°C. It is then pumped through heat transfer pump 4 to boost its pressure and sent to absorption heat pump 6, which transfers the heat from the heat transfer water. After releasing the heat, the heat transfer water cools to approximately 65°C before returning to black water heat exchanger 3 to draw heat again, repeating the cycle. To prevent the heat transfer water from decompressing and vaporizing, a constant-pressure water replenishment device 5 is installed at the inlet of heat transfer pump 4 to maintain the pressure in the circulation system.

[0039] Steam production

[0040] After deoxygenation by deaerator 9, the desalted water is pressurized by deoxygenation pump 10 and delivered to absorption heat pump 6. This absorption heat pump uses a water-lithium bromide working fluid pair. After extracting heat from the heat transfer water, it transfers some of this heat to the deoxygenated water. The deoxygenated water absorbs the heat and vaporizes to produce 0.8 MPaG low-pressure saturated steam, which then enters steam buffer tank 7 for gas-liquid separation. The remaining heat from the heat transfer water is extracted by circulating cooling water unit 11 to ensure system energy balance.

[0041] Low-pressure steam compression

[0042] The saturated low-pressure steam after separation at the outlet of the steam buffer tank 7 is compressed by the steam compressor 8 to 1.3 MPaG, 220°C superheated steam for use by various users.

[0043] This technology uses non-filtered, full-flux black water direct heat extraction technology and a fully welded plate-type black water-specific heat exchanger to extract heat from the black water at the outlet of the low-pressure flash tank of the coal gasification unit. Desalted water is used as the heat medium, and then absorption heat pump technology is used to recover and convert the heat in the black water to generate low-pressure steam. After being compressed into medium-pressure steam by a steam compressor, it is provided to various users.

[0044] It is worth noting that the entire device is controlled by a master control button. Since the devices matched with the control button are commonly used devices and belong to existing mature technologies, their electrical connection relationships and specific circuit structures will not be described in detail here.

[0045] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A steam generation device for recovering waste heat from gasified black water, characterized by: Including waste heat recovery system, heat medium water circulation system, steam production system and low-pressure steam compression system; The waste heat recovery system comprises a low-pressure flash tank (1), a vacuum flash tank (2) and a black water heat exchanger (3), wherein the low-pressure flash tank (1) and the vacuum flash tank (2) are respectively connected to the black water inlet and the black water outlet of the black water heat exchanger (3); The heat medium water circulation system comprises a heat medium water circulation pump (4) and an absorption heat pump (6), wherein the heat medium water circulation pump (4) is connected to the heat medium water outlet of the black water heat exchanger (3) and the heat medium water inlet of the absorption heat pump (6), respectively, and the heat medium water outlet of the absorption heat pump (6) is connected to the heat medium water inlet of the black water heat exchanger (3); The steam production system comprises a deaerator device (9), a deaeration water pump (10) and a steam buffer tank (7), the deaeration water pump (10) is connected to the deaeration water outlet of the deaerator device (9) and the deaeration water inlet of the absorption heat pump (6), and the steam buffer tank (7) is connected to the deaeration water outlet of the absorption heat pump (6); The low-pressure steam compression system comprises a steam compressor (8), wherein a steam inlet of the steam compressor (8) is connected to a steam outlet of a steam buffer tank (7).

2. The steam generation device for recovering waste heat from gasified black water according to claim 1, characterized in that: A flash tank liquid level control valve (12) is connected between the black water heat exchanger (3) and the vacuum flash tank (2).

3. The steam generation device for recovering waste heat from gasified black water according to claim 1, characterized in that: A constant pressure water replenishing device (5) is connected between the black water heat exchanger (3) and the heat medium water circulation pump (4).

4. The steam generation device for recovering waste heat from gasified black water according to claim 1, characterized in that: A heat medium water flow control valve (13) is provided between the heat medium water circulation pump (4) and the absorption heat pump (6), and a heat medium water return control valve (14) is connected between the heat medium water inlet and the heat medium water outlet of the absorption heat pump (6).

5. The steam generation device for recovering waste heat from gasified black water according to claim 1, characterized in that: The absorption heat pump (6) is connected to a circulating cooling water device (11).

6. The steam generation device for recovering waste heat from gasified black water according to claim 1, characterized in that: The deionized water inlet of the deaerator device (9) is provided with a deaerator liquid level control valve (17), and the deaerator device (9) is provided with a deaerator pressure control valve (16).

7. The steam generation device for recovering waste heat from gasified black water according to claim 1, characterized in that: A compressor return valve (15) is connected between the steam inlet and the steam outlet of the steam compressor (8).

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