Black water waste heat efficient power generation system

Abstract

The utility model relates to the technical field of waste heat recovery, and discloses a black water waste heat efficient power generation system which comprises a multi-stage flash evaporation device, a heat exchange device, a power generation device and a condensation recovery device. The heat exchange device is used for receiving flash evaporation steam generated by the multi-stage flash evaporation device, carrying out heat exchange and condensing the flash evaporation steam into liquid, and the power generation device is used for receiving clean steam generated by the heat exchange device for power generation; and the condensation recovery device is used for cooling the non-condensable gas and steam generated by the multi-stage flash evaporation device and the heat exchange device, recovering condensed water and disposing the non-condensable gas. According to the utility model, the multi-stage flash evaporation device is adopted to carry out stage-by-stage flash evaporation treatment on the high-temperature black water produced by the gasification furnace to generate flash evaporation steam with different pressures, so that waste heat resources in the black water are fully utilized, and the utilization rate of the waste heat of the black water is improved.

Description

Technical Field

[0001] This utility model relates to the field of waste heat recovery technology, specifically a high-efficiency black water waste heat power generation system. Background Technology

[0002] The pulverized coal gasification process generates a large amount of relatively high-temperature black water. The existing process mainly involves flash evaporation to treat non-condensable gases, and the liquid portion is cooled and discharged, resulting in a huge waste of waste heat and a huge waste of water resources and electricity consumption during the cooling process.

[0003] The pulverized coal gasification process system mainly consists of a gasifier system, a syngas purification system, and a black water treatment system. The gasifier is equipped with a gasification chamber and a quench chamber; the syngas purification system consists of a cyclone separator and a scrubbing tower; the black water treatment system consists of a high-pressure flash tank, a low-pressure flash tank, and a condenser system. The main function of the black water treatment system is to treat the black water containing slag and ash generated during the gasification and syngas purification processes, separating solid particulate matter and non-condensable gases dissolved in the black water, and achieving a very small portion of the black water reuse. The high-temperature black water undergoes high-speed flash treatment to remove non-condensable gases and recover a very small portion of the water, followed by low-speed flash treatment to recover another small portion of the water. After clarification, fine slag is recovered for reuse, while the ash water is discharged as wastewater.

[0004] The search revealed that existing technologies suffer from problems such as waste of waste heat and water resources from gasification of black water, as well as significant electricity consumption. Utility Model Content

[0005] This invention provides a high-efficiency blackwater waste heat power generation system, which solves the problems of "waste of blackwater waste heat and water resources and large-scale power consumption" mentioned in the background technology.

[0006] To achieve the above-mentioned technical objectives, the technical solution of this utility model is implemented as follows:

[0007] A high-efficiency blackwater waste heat power generation system includes a multi-stage flash evaporation device, a heat exchange device, a power generation device, and a condensation recovery device. The multi-stage flash evaporation device is used to perform multi-stage flash evaporation treatment on the blackwater produced by the gasifier, generating flash steam at different pressures. The heat exchange device is used to receive the flash steam generated by the multi-stage flash evaporation device and exchange heat, condensing the flash steam into liquid. The power generation device is used to receive the clean steam generated by the heat exchange device for power generation. The condensation recovery device is used to cool the non-condensable gases and steam generated by the multi-stage flash evaporation device and the heat exchange device, recover the condensate, and dispose of the non-condensable gases. The multi-stage flash evaporation device, the heat exchange device, the power generation device, and the condensation recovery device are connected by transmission pipelines.

[0008] Furthermore, the multi-stage flash evaporation device includes at least one high-pressure flash evaporation tank and one low-pressure flash evaporation tank. The high-pressure flash evaporation tank is used to perform high-pressure flash evaporation treatment on the black water, and the low-pressure flash evaporation tank is used to perform low-pressure flash evaporation treatment on the black water after high-pressure flash evaporation treatment.

[0009] Furthermore, the high-pressure flash tank is configured as a three-stage system: a primary high-pressure flash tank, a secondary high-pressure flash tank, and a tertiary high-pressure flash tank. The primary high-pressure flash tank receives black water produced by the gasifier and evaporates it into primary high-pressure flash steam at a pressure approximately 50% of the black water discharge pressure. The water discharged from the primary high-pressure flash tank enters the secondary high-pressure flash tank, which receives water discharged from the primary high-pressure flash tank and evaporates it into secondary high-pressure flash steam at a pressure approximately 25% of the black water discharge pressure. The water discharged from the secondary high-pressure flash tank and the liquid condensed from the steam in the primary high-pressure flash tank after heat exchange enter the tertiary high-pressure flash tank, which flashes steam at a pressure approximately 15% of the black water discharge pressure.

[0010] Furthermore, the first-stage high-pressure flash tank, the second-stage high-pressure flash tank, and the third-stage high-pressure flash tank are connected in series. The liquid discharge portion of the third-stage high-pressure flash tank enters the low-pressure flash tank. The low-pressure flash tank flashes out steam with a pressure of approximately 0.2 MPa. The heat exchange device includes at least two evaporators. The steam inlet of the evaporator is connected to the flash steam outlet of the multi-stage flash evaporation device to receive the flash steam and condense it into liquid through heat exchange.

[0011] Furthermore, the evaporator includes a primary high-pressure evaporator and a secondary high-pressure evaporator. The steam inlet of the primary high-pressure evaporator is connected to the flash steam outlet of the primary high-pressure flash tank, receiving primary high-pressure flash steam and condensing it through heat exchange. The steam inlet of the secondary high-pressure evaporator is connected to the flash steam outlet of the secondary high-pressure flash tank, receiving secondary high-pressure flash steam and condensing it through heat exchange.

[0012] Furthermore, the power generation device is a steam-assisted condensing power generation device. The steam inlet of the steam-assisted condensing power generation device is connected to the steam outlet of the heat exchange device, and is used to receive the clean steam generated by the heat exchange device for power generation. The generated electricity is connected to the plant's power system after passing through a frequency converter. The condensation recovery device includes at least one high-pressure condenser and one low-pressure condenser. The high-pressure condenser is used to cool the mixture of steam and non-condensable gas generated by the high-pressure flash tank in the multi-stage flash evaporation device, and the low-pressure condenser is used to cool the steam generated by the low-pressure flash tank.

[0013] Furthermore, the high-pressure condenser is a three-stage high-pressure condenser, used to cool the mixture of steam and non-condensable gas flashed from the three-stage high-pressure flash tank. After cooling, the non-condensable gas enters the flare combustion treatment pipeline for combustion treatment, and the condensate is recycled for use in other process systems. The low-pressure condenser is used to cool the steam flashed from the low-pressure flash tank, and the condensate is recycled for use in other process systems. The liquid discharge portion of the low-pressure flash tank enters the ash water treatment tank. The transmission pipeline is used for, but not limited to, the transmission of black water, flash steam, condensate, and non-condensable gas.

[0014] The beneficial effects of this invention are as follows: During operation, this high-efficiency blackwater waste heat power generation system utilizes a multi-stage flash evaporation device to progressively flash-evaporate the high-temperature blackwater produced by the gasifier, generating flash steam at different pressures. This fully utilizes the waste heat resources in the blackwater, improving its utilization rate. Simultaneously, a condensation recovery device cools non-condensable gases and steam, recovering the condensate for use in other process systems, further reducing water waste. Compared to existing technologies, this invention not only reduces blackwater waste heat but also lowers water and electricity consumption during the cooling process, achieving highly efficient energy utilization.

[0015] This blackwater waste heat high-efficiency power generation system integrates multi-stage flash evaporation devices, heat exchange devices, power generation devices, and condensation recovery devices to form a complete system. This directly reduces the plant's electricity consumption by converting blackwater waste heat into electrical energy, thus lowering the overall energy consumption of the process system. Furthermore, the condensation recovery device cools non-condensable gases and steam, reducing energy consumption from flare combustion and further enhancing the system's economic efficiency. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process flow structure of this utility model.

[0017] In the diagram: 1. First-stage high-pressure flash tank; 2. First-stage high-pressure evaporator; 3. Steam-assisted condensing power generation unit; 4. Second-stage high-pressure flash tank; 5. Second-stage high-pressure evaporator; 6. Third-stage high-pressure flash tank; 7. Third-stage high-pressure condenser; 8. Low-pressure flash tank; 9. Low-pressure condenser. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0019] Please see Figure 1This utility model discloses a high-efficiency blackwater waste heat power generation system, including a multi-stage flash evaporation device, a heat exchange device, a power generation device, and a condensation recovery device. The multi-stage flash evaporation device, heat exchange device, power generation device, and condensation recovery device are connected via transmission pipelines. The multi-stage flash evaporation device is used to perform multi-stage flash evaporation treatment on the blackwater produced by the gasifier, generating flash steam at different pressures. Specifically, the multi-stage flash evaporation device includes at least one high-pressure flash tank and one low-pressure flash tank 8. The design of the low-pressure flash tank 8 allows for effective recovery of waste heat from the blackwater even at lower pressures, further improving the overall efficiency of the system. The high-pressure flash tank is used to... Blackwater undergoes high-pressure flash evaporation treatment. Specifically, the high-pressure flash evaporation tank is configured in three stages: a primary high-pressure flash evaporation tank 1, a secondary high-pressure flash evaporation tank 4, and a tertiary high-pressure flash evaporation tank 6. This three-stage design effectively reduces the pressure of the blackwater in stages, thereby generating flash steam at different pressures and maximizing the recovery of waste heat from the blackwater. The primary high-pressure flash evaporation tank 1 receives the blackwater produced by the gasifier and evaporates it to a pressure of approximately 50% of the blackwater discharge pressure. The water discharged from the primary high-pressure flash evaporation tank 1 enters the secondary high-pressure flash evaporation tank 4, which receives the water discharged from the primary high-pressure flash evaporation tank 1 and evaporates it to a pressure of approximately 50% of the blackwater discharge pressure. The secondary high-pressure flash steam, approximately 25% of the blackwater discharge pressure, is used for heat exchange. The water discharged from the secondary high-pressure flash tank 4 and the liquid condensed from the steam in the primary high-pressure flash tank 1 enter the tertiary high-pressure flash tank 6. The tertiary high-pressure flash tank 6 flashes out steam at a pressure approximately 15% of the blackwater discharge pressure. The primary high-pressure flash tank 1, secondary high-pressure flash tank 4, and tertiary high-pressure flash tank 6 are connected in series. The liquid discharge portion from the tertiary high-pressure flash tank 6 enters the low-pressure flash tank 8. The low-pressure flash tank 8 flashes out steam at a pressure of approximately 0.2 MPa. The heat exchange device includes at least two evaporators, and the steam inlet of the evaporators is connected to the multi-stage flash evaporation device. The flash steam outlet is connected to receive flash steam and condense it into liquid through heat exchange. Furthermore, the evaporator includes a first-stage high-pressure evaporator 2 and a second-stage high-pressure evaporator 5, so that flash steam at different pressures can exchange heat in the corresponding evaporators, ensuring the effective utilization of thermal energy and efficient condensation of steam. The steam inlet of the first-stage high-pressure evaporator 2 is connected to the flash steam outlet of the first-stage high-pressure flash tank 1 to receive the first-stage high-pressure flash steam and condense it through heat exchange. The steam inlet of the second-stage high-pressure evaporator 5 is connected to the flash steam outlet of the second-stage high-pressure flash tank 4 to receive the second-stage high-pressure flash steam and condense it through heat exchange.

[0020] The low-pressure flash tank 8 is used to perform low-pressure flash treatment on black water that has been treated by high-pressure flash evaporation.

[0021] The heat exchanger receives and condenses the flash steam generated by the multi-stage flash evaporator into liquid. The power generation unit receives the clean steam generated by the heat exchanger to generate electricity. Specifically, the power generation unit is a steam-assisted condensing power generation unit 3. The steam inlet of the steam-assisted condensing power generation unit 3 is connected to the steam outlet of the heat exchanger to receive the clean steam generated by the heat exchanger for power generation. The generated electricity is connected to the plant's power system after passing through a frequency converter. The condensation recovery unit includes at least one high-pressure condenser and one low-pressure condenser 9. The high-pressure condenser is used to cool the steam generated by the high-pressure flash tank in the multi-stage flash evaporator. The mixture of steam and non-condensable gases is cooled by a low-pressure condenser 9, which is used to cool the steam generated by the low-pressure flash tank 8. Furthermore, a three-stage high-pressure condenser 7 is used to cool the mixture of steam and non-condensable gases flashed out of the three-stage high-pressure flash tank 6. After cooling, the non-condensable gases enter the flare combustion treatment pipeline for combustion treatment. The condensate is recycled for use in other process systems. The liquid discharge portion of the low-pressure flash tank 8 enters the ash water treatment pool. The transmission pipeline is used to transport black water, flash steam, condensate, and non-condensable gases.

[0022] The condensation recovery unit is used to cool non-condensable gases and steam generated by multi-stage flash evaporation units and heat exchange units, recover condensate, and dispose of non-condensable gases.

[0023] This utility model also discloses a method for high-efficiency power generation from blackwater waste heat, including the following steps:

[0024] S1: The black water produced by the gasifier is subjected to multi-stage flash evaporation through a multi-stage flash evaporation device to generate flash steam at different pressures. Specifically, the multi-stage flash evaporation process includes:

[0025] S101: Black water is flash-evaporated in the first-stage high-pressure flash tank 1 to generate first-stage high-pressure flash steam with a pressure of about 50% of the black water discharge pressure.

[0026] S102: The water discharged from the primary high-pressure flash tank 1 is transported to the secondary high-pressure flash tank 4 for flash evaporation, generating secondary high-pressure flash steam with a pressure of approximately 25% of the black water discharge pressure;

[0027] S103: The water discharged from the secondary high-pressure flash tank 4 and the liquid condensed by heat exchange with the primary high-pressure flash steam are transported to the tertiary high-pressure flash tank 6 for flash evaporation, generating steam with a pressure of about 15% of the black water discharge pressure.

[0028] S104: The liquid discharge portion of the three-stage high-pressure flash tank 6 is transported to the low-pressure flash tank 8 for flash evaporation, generating steam with a pressure of approximately 0.2 MPa;

[0029] S105: The heat exchange device includes a first-stage high-pressure evaporator 2 and a second-stage high-pressure evaporator 5, which respectively receive the first-stage high-pressure flash steam and the second-stage high-pressure flash steam and condense them through heat exchange.

[0030] S106: The power generation unit is a condensing steam generator 3, and the power generated by it is connected to the plant's power system after passing through a frequency converter.

[0031] S2: The flash steam generated by the multi-stage flash evaporator is received by the heat exchanger and heat exchanged, and the flash steam is condensed into liquid.

[0032] S3: Power generation is achieved by receiving clean steam generated by the heat exchanger through the power generation unit;

[0033] S4: The non-condensable gases and steam generated by the multi-stage flash evaporation unit and heat exchange unit are cooled by a condensation recovery unit, which recovers condensate and disposes of the non-condensable gases. Specifically, the condensation recovery process includes:

[0034] S401: The mixture of steam and non-condensable gas flashed from the third-stage high-pressure flash tank 6 is cooled by the third-stage high-pressure condenser 7, and the non-condensable gas is transported to the flare combustion treatment pipeline for combustion treatment. The condensate is recovered for use in other process systems.

[0035] S402: The steam flashed from the low-pressure flash tank 8 is cooled by the low-pressure condenser 9, the condensate is recovered for use in other process systems, and the liquid discharge portion of the low-pressure flash tank is transported to the ash water treatment pool.

[0036] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A black water waste heat high efficiency power generation system, characterized in that, The multi-stage flash evaporation device, heat exchange device, power generation device and condensation recovery device are connected through transmission pipelines.

2. The black water waste heat high efficiency power generation system of claim 1, wherein, The high-pressure flash tank is provided as three stages, namely a first-stage high-pressure flash tank (1), a second-stage high-pressure flash tank (4) and a third-stage high-pressure flash tank (6). The first-stage high-pressure flash tank (1) receives the black water produced by the gasifier and evaporates first-stage high-pressure flash steam at a pressure of about 50% of the discharge pressure of the black water. The water discharged from the first-stage high-pressure flash tank (1) enters the second-stage high-pressure flash tank (4). The second-stage high-pressure flash tank (4) receives the water discharged from the first-stage high-pressure flash tank (1) and evaporates second-stage high-pressure flash steam at a pressure of about 25% of the discharge pressure of the black water. The water discharged from the second-stage high-pressure flash tank (4) and the liquid condensed after steam heat exchange of the first-stage high-pressure flash tank (1) enter the third-stage high-pressure flash tank (6). The third-stage high-pressure flash tank (6) evaporates steam at a pressure of about 15% of the discharge pressure of the black water.

3. The black water waste heat high efficiency power generation system of claim 2, wherein, The first-stage high-pressure flash tank (1), the second-stage high-pressure flash tank (4) and the third-stage high-pressure flash tank (6) are connected in series. The liquid discharge part of the third-stage high-pressure flash tank (6) enters the low-pressure flash tank (8). The low-pressure flash tank (8) evaporates steam at a pressure of about 0.2 MPa. The heat exchange device includes at least two evaporators. The steam inlet of the evaporator is connected to the flash steam outlet of the multi-stage flash evaporation device, for receiving flash steam and condensing it into liquid by heat exchange.

4. The black water waste heat high efficiency power generation system of claim 3, wherein, The evaporator includes a first-stage high-pressure evaporator (2) and a second-stage high-pressure evaporator (5). The steam inlet of the first-stage high-pressure evaporator (2) is connected to the flash steam outlet of the first-stage high-pressure flash tank (1), for receiving first-stage high-pressure flash steam and condensing it by heat exchange. The steam inlet of the second-stage high-pressure evaporator (5) is connected to the flash steam outlet of the second-stage high-pressure flash tank (4), for receiving second-stage high-pressure flash steam and condensing it by heat exchange.

5. The black water waste heat high efficiency power generation system of claim 4, wherein, ​ 6. The black water waste heat high efficiency power generation system of claim 4, wherein, The power generation device is a supplementary steam condensing type power generation device (3), a steam inlet of the supplementary steam condensing type power generation device (3) is connected with a steam outlet of the heat exchange device, and is used for receiving clean steam generated by the heat exchange device to generate power, and the generated power is connected to a power system of a plant area after passing through a frequency inverter, the condensing recovery device includes at least one high-pressure condenser and one low-pressure condenser (9), the high-pressure condenser is used for cooling steam and non-condensable gas mixture generated by a high-pressure flash tank in the multi-stage flash device, and the low-pressure condenser (9) is used for cooling steam generated by the low-pressure flash tank (8).

7. The black water waste heat high efficiency power generation system of claim 6, wherein, The high-pressure condenser is a three-stage high-pressure condenser (7) used for cooling steam and non-condensable gas mixture flashed out of the three-stage high-pressure flash tank (6), the non-condensable gas is burned and disposed in a flare combustion disposal pipeline after being cooled, and condensed water is recycled and used in other process systems, the low-pressure condenser (9) is used for cooling steam flashed out of the low-pressure flash tank (8), condensed water is recycled and used in other process systems, a liquid discharge part of the low-pressure flash tank (8) is discharged into a grey water disposal pool, and the transmission pipeline is used for transmitting black water, flash steam, condensed water and non-condensable gas.

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