CN216716618U - Comprehensive utilization system for waste heat during furnace shutdown - Google Patents

Abstract

The utility model discloses a comprehensive utilization system of waste heat during shutdown, which comprises an air source heat pump, a water-water heat exchanger, a gas-water heat exchanger and a heat storage tank, wherein the heat storage tank is connected with a hot water supply pipe and a hot water return pipe, the hot water return pipe is communicated with the hot water supply pipe through an air source heat pump, the water-water heat exchanger and the gas-water heat exchanger, an air inlet of the air source heat pump is communicated with a chimney, a water inlet of the water-water heat exchanger is communicated with a sewage hot water port of a boiler, and an air inlet of the gas-water heat exchanger is communicated with a high-temperature flue gas outlet of an economizer. The utility model recovers the waste heat of the flue gas of the electric furnace in stages by changing the treatment steps of the flue gas in the prior art, wherein the air source heat pump preheats the circulating water backwater by using the low-temperature flue gas of the chimney. The system effectively stores the high-quality flue gas waste heat after the furnace is stopped, can be used for heating condensed water, fuel gas and the like when needed, and is relatively flexible in heat utilization.

Description

Comprehensive utilization system for waste heat during furnace shutdown

Technical Field

The utility model is suitable for a waste heat boiler of a gas turbine unit, and relates to a comprehensive utilization system of waste heat during blowing out.

Background

The natural gas is used as a clean fuel, the flue gas after combustion in the gas turbine mainly contains carbon dioxide and water, and compared with the flue gas of a coal-fired unit, the flue gas is much cleaner, and the risks of acid corrosion and ash abrasion are reduced. With the national advocation of low carbon emission and energy conservation, the power plant is used as a large household for energy consumption and carbon emission, and the comprehensive utilization of energy, especially in the aspect of waste heat utilization, is more and more emphasized.

The high-quality heat energy such as high-temperature steam, high-temperature hot water, high-temperature hot flue gas and the like exists in the shutdown process of the waste heat boiler of the gas turbine unit, and the forced cooling and the natural cooling have great energy loss. For example, the boiler continuous and fixed discharge sewage has the advantages that the saturated water temperature (the temperature reaches 250 ℃) under the rated pressure of the boiler has extremely high heat energy, the discharge capacity is about 3% of the evaporation capacity of the boiler, and a lot of enterprises directly discharge the high-temperature water into a trench to cause the waste of a large amount of heat energy and water resources. And high-temperature hot flue gas has great heat loss no matter blowing out for heat preservation and pressure maintaining or natural cooling.

Chinese patent application publication No. CN110296420A discloses a waste heat utilization system for SCR in a waste incineration power station, which utilizes a set of closed circulating water heat exchange system to exchange heat of the waste heat of the flue gas after SCR to closed circulating water through a surface heat exchanger. And respectively recycled into a steam-water system, a combustion air system or a garbage pit according to the needs in the factory. The system is independent and adjustable, the operation is reliable, the flue gas waste heat after SCR can be flexibly utilized to improve the heat energy utilization efficiency of the power station, and the steam extraction of a steam turbine is reduced; or used for improving the temperature of primary air/garbage entering the furnace and avoiding the input of an auxiliary combustion system. According to the practical scheme and the white removal requirement of the chimney, the utility model can improve the thermal efficiency of the whole plant by 0.3-1.2%.

Chinese patent application publication No. CN110296388A discloses a waste heat utilization system and method for heating cooling water return water of a slag cooler by using boiler blow-down water, the system includes a boiler body water drainage water inlet pipe, a continuous drainage water inlet pipe, a first valve, a heat exchange pipe, a slag cooler cooling water return pipe, a cooling tower, a second valve, a hot water tank, an industrial water inlet pipe, a tap water inlet pipe, a third valve, a hot water loading port, a fourth valve, and a hot water and heat supply pipeline.

Although numerous boiler waste heat utilization systems and related processes are disclosed in the prior art, high-quality heat energy such as high-temperature flue gas, high-temperature steam and high-temperature hot water during shutdown cannot be effectively utilized.

SUMMERY OF THE UTILITY MODEL

The utility model aims to overcome the defects in the prior art, and provides a comprehensive utilization system for waste heat during the blowing-out period, which has a reasonable structural design, has a simple structure and can effectively solve the problem that the residual high-quality heat energy of a boiler cannot be effectively utilized during the current shutdown period.

The technical scheme adopted by the utility model for solving the problems is as follows: the comprehensive utilization system of waste heat during shutdown is characterized by comprising an air source heat pump, a water-water heat exchanger, a gas-water heat exchanger and a heat storage tank, wherein the heat storage tank is connected with a hot water supply pipe and a hot water return pipe, the hot water return pipe is communicated with the hot water supply pipe through the air source heat pump, the water-water heat exchanger and the gas-water heat exchanger, an air inlet of the air source heat pump is communicated with a chimney, a water inlet of the water-water heat exchanger is communicated with a sewage hot water port of a boiler, and an air inlet of the gas-water heat exchanger is communicated with a high-temperature flue gas outlet of an economizer.

Furthermore, a speed-regulating circulating pump is connected to the hot water return pipe.

Further, the water outlet of the water-water heat exchanger is connected to a sewage draining pool.

Furthermore, an air source of the air source heat pump is led out from a chimney and can absorb and utilize low-temperature flue gas at the temperature of 60-80 ℃ to heat circulating water return water of a heat supply network, and the flue gas side and the water side of the heat supply network are respectively communicated with the air source heat pump. The air source heat pump body needs to have the performances of moisture resistance, corrosion resistance and the like.

Furthermore, the water-water heat exchanger utilizes the continuous-discharge and fixed-discharge sewage hot water of the boiler, the water temperature is 160 ℃, the heating heat supply network returns water, and the heated water is discharged to a sewage discharge pool.

Further, the gas-water heat exchanger utilizes high-temperature flue gas (about 300 ℃) after the high-pressure economizer to further heat circulating water backwater, and the heated flue gas is discharged into the atmosphere.

Furthermore, the heat storage tank can store circulating water hot water after heat exchange to store energy, and can be used for heating condensed water, fuel gas and the like when needed. The temperature of the water at the upper side and the lower side in the heat storage tank is different, and due to the density difference, the hot water is at the upper layer, and the cold water is at the lower layer.

Furthermore, the speed regulation circulating pump can flexibly adjust the circulating water quantity according to the change of the circulating water temperature and the water temperature in the heat storage tank.

Compared with the prior art, the utility model has the following advantages and effects:

1. the method comprises the steps of changing the treatment steps of flue gas in the prior art, and recycling the waste heat of the flue gas of the electric furnace in a grading manner, wherein the air source heat pump preheats the circulating backwater by using the low-temperature flue gas of a chimney.

2. The high-quality flue gas waste heat after the furnace is stopped is effectively stored, and can be used for heating condensed water, fuel gas and the like when needed, so that the heat is utilized flexibly.

Drawings

FIG. 1 is a schematic diagram of the system architecture of the present invention.

In the figure: the system comprises an air source heat pump 1, a water-water heat exchanger 2, an air-water heat exchanger 3, a heat storage tank 4, a speed regulation circulating pump 5, a hot water supply pipe 6, a hot water return pipe 7, a chimney 8, a boiler 9, an economizer 10 and a sewage drainage tank 11.

Detailed Description

The present invention will be described in further detail below by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and are not to be construed as limiting the present invention.

Examples are given.

Referring to fig. 1, in this embodiment, a system for comprehensively utilizing waste heat during shutdown includes an air source heat pump 1, a water-water heat exchanger 2, a gas-water heat exchanger 3, and a heat storage tank 4, the heat storage tank 4 is connected to a hot water supply pipe 6 and a hot water return pipe 7, the hot water return pipe 7 is connected to a speed-adjusting circulation pump 5, the hot water return pipe 7 is communicated with the hot water supply pipe 6 via the air source heat pump 1, the water-water heat exchanger 2, and the gas-water heat exchanger 3, an air inlet of the air source heat pump 1 is communicated with a chimney 8, a water inlet of the water-water heat exchanger 2 is communicated with a hot water drainage port of a boiler 9, a water outlet of the water-water heat exchanger 2 is connected to a sewage drainage pool 11, and an air inlet of the gas-water heat exchanger 3 is communicated with a high-temperature flue gas outlet of an economizer 10.

Specifically, an air source of the air source heat pump 1 is led out from a chimney 8 and can absorb and utilize low-temperature flue gas at the temperature of 60-80 ℃ to heat circulating water return water of a heat supply network, and the flue gas side and the water side of the heat supply network are respectively communicated with the air source heat pump 1. The water-water heat exchanger 2 utilizes the continuous discharge and fixed discharge of the sewage hot water of the boiler 9, the water temperature is 160 ℃, the heating heat supply network returns water, and the heated water is discharged to the sewage drainage tank 11. The gas-water heat exchanger 3 further heats circulating water backwater by using high-temperature flue gas (about 300 ℃) after the high-pressure economizer 10, and the heated flue gas is discharged into the atmosphere. The heat storage tank 4 can store circulating water hot water after heat exchange to store energy, and can be used for heating condensed water, fuel gas and the like when needed. The upper and lower sides in the heat storage tank 4 have different water temperatures, and hot water is on the upper layer and cold water is on the lower layer due to the density difference. The speed-regulating circulating pump 5 can flexibly regulate the circulating water quantity according to the change of the circulating water temperature and the water temperature in the heat storage tank.

In this embodiment, the waste heat during the furnace shutdown contains three parts: the first part of heat sources are low-grade heat energy of low-temperature flue gas in a chimney 8 and are absorbed by an air source heat pump 1 to preheat return water of a heat supply network; the second part of heat sources are from fixed-row and continuous-row sewage hot water of a boiler 9, and heat return water of a heat supply network through a water-water heat exchanger 2; the third part of heat sources are high-temperature flue gas from the high-pressure economizer 10, the heat supply network backwater is heated by the gas-water heat exchanger 3, and finally the temperature of the heat supply network backwater is heated to 110 ℃, and the heat supply network backwater is sent to the heat storage tank 4 for storage. Wherein, the hot water in the heat storage tank 4 and the cold water at the lower part can generate density difference due to different temperatures, and the cold water is taken away by the speed-regulating circulating pump 5 at the bottom of the tank to continuously absorb waste heat and maintain the temperature in the tank at about 100 ℃. The speed-regulating circulating pump 5 flexibly regulates the flow of circulating water according to the temperature in the tank.

Those not described in detail in this specification are well within the skill of the art.

In addition, it should be noted that the above contents described in the present specification are only illustrations of the structures of the present invention. All equivalent variations of the structures, features and principles described in accordance with the present inventive concepts are included within the scope of the present invention. Those skilled in the art to which the utility model relates will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the utility model as disclosed in the accompanying claims.

Claims (3)

1. The comprehensive utilization system of waste heat during shutdown is characterized by comprising an air source heat pump (1), a water-water heat exchanger (2), a gas-water heat exchanger (3) and a heat storage tank (4), wherein the heat storage tank (4) is connected with a hot water supply pipe (6) and a hot water return pipe (7), the hot water return pipe (7) is communicated with the hot water supply pipe (6) through the air source heat pump (1), the water-water heat exchanger (2) and the gas-water heat exchanger (3), an air inlet of the air source heat pump (1) is communicated with a chimney (8), a water inlet of the water-water heat exchanger (2) is communicated with a sewage discharge hot water port of a boiler (9), and an air inlet of the gas-water heat exchanger (3) is communicated with a high-temperature flue gas outlet of an economizer (10).

2. The system for comprehensive utilization of waste heat during blowing out as claimed in claim 1, wherein a speed-regulating circulation pump (5) is connected to said hot water return pipe (7).

3. The system for comprehensive utilization of waste heat during blowing out according to claim 1, wherein the water outlet of the water-water heat exchanger (2) is connected to a sewage drainage tank (11).

Images