A desulfurization slurry heat extraction and water intake device using the extraction steam of a unit and its working method

Abstract

The present invention discloses a desulfurization slurry heat extraction and water intake device using the extraction steam of a unit and its working method, which includes a boiler, a steam turbine, an ejector tower and a heat network water heater; the steam outlet of the boiler is connected to the inlet of the steam turbine, the outlet of the steam turbine is connected to the steam inlet of the ejector tower, the steam outlet of the ejector tower is connected to the hot end of the heat network water heater, and the cold end of the heat network water heater is connected to the heat network water. The boiler uses the heat released by coal combustion to heat the liquid water, turning it into a high-temperature and high-pressure gas and entering the steam turbine. After doing work in the steam turbine, it enters the ejector tower. The steam generated by ejection in the ejector tower enters the heat network water heater from the steam outlet of the ejector tower, and the steam exchanges heat with the heat network water in the heat network water heater to heat the heat network water. The recovery and utilization of the extraction steam of the unit and the waste heat and moisture of the desulfurization slurry are realized.

Description

Technical Field

[0001] The present invention belongs to the field of waste heat recovery, and relates to a desulfurized slurry heat extraction and water intake device using the extraction steam of a unit and its working method. Background Art

[0002] The energy loss in a thermal power plant mainly comes from the cold end loss in the working medium cycle work and the waste heat loss of the flue gas. Among them, the cold end loss has been effectively reduced by increasing regenerative heating and reheating, implementing combined heat and power generation, etc. The main energy loss is concentrated in the heat loss of the flue gas waste heat. Therefore, it is necessary to further recover and utilize the flue gas waste heat in an economical and reasonable way. At present, after the wet desulfurization of the coal-fired flue gas in a desulfurization tower, due to the high temperature of the flue gas and the presence of a large amount of water vapor, a spray heat exchanger is mostly used to reduce the flue gas temperature and recover and utilize the latent heat of the water vapor in the flue gas.

[0003] However, the heat transfer coefficient of the flue gas is low, and the required spray heat exchanger has a large volume, and the cost and construction transformation are relatively complex. Due to the presence of a certain amount of water vapor and acidic impurities in the flue gas, there is a certain corrosion to the spray heat exchanger. 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 desulfurized slurry heat extraction and water intake device using the extraction steam of a unit and its working method, so as to realize the recovery and utilization of the extraction steam of the unit and the waste heat and moisture of the desulfurized slurry.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A desulfurized slurry heat extraction and water intake device using the extraction steam of a unit, including a boiler, a steam turbine, an ejector tower, and a heat network water heater;

[0007] The steam outlet of the boiler is connected to the inlet of the steam turbine, the outlet of the steam turbine is connected to the steam inlet of the ejector tower, the steam outlet of the ejector tower is connected to the hot end of the heat network water heater, and the cold end of the heat network water heater is connected to the heat network water.

[0008] Preferably, the outlet of the steam turbine is divided into two paths, one path is connected to the steam inlet of the ejector tower, and the other path is connected to the inlet of the condenser, and the outlet of the condenser is connected to the water inlet of the boiler.

[0009] Furthermore, a water pump is provided between the outlet of the condenser and the water inlet of the boiler.

[0010] Preferably, the flue gas outlet of the boiler is connected to the flue gas inlet of the wet desulfurization tower, and the flue gas outlet of the wet desulfurization tower is connected to a chimney.

[0011] Furthermore, the slurry outlet of the wet desulfurization tower is connected to the slurry inlet of the ejector tower, and the slurry outlet of the ejector tower is connected to the slurry inlet of the wet desulfurization tower.

[0012] Furthermore, a desulfurized slurry outlet pump is provided between the slurry outlet of the wet desulfurization tower and the slurry inlet of the ejector tower, and a desulfurized slurry inlet pump is provided between the slurry outlet of the ejector tower and the slurry inlet of the wet desulfurization tower.

[0013] Preferably, a desulfurized slurry header and a desulfurized slurry ejector are arranged in the ejector tower. The desulfurized slurry ejector is located above the desulfurized slurry header. The desulfurized slurry header is connected to the slurry inlet of the ejector tower, and the desulfurized slurry ejector is connected to the steam turbine outlet.

[0014] Preferably, a demister is arranged in the ejector tower, and the demister is located above the steam inlet of the ejector tower.

[0015] The working process of a desulfurized slurry heat extraction and water intake device using the extraction steam of the unit based on any one of the above is as follows:

[0016] The boiler uses the heat released by coal combustion to heat the liquid water, turning it into a high-temperature and high-pressure gas and entering the steam turbine. After doing work in the steam turbine, it enters the ejector tower. The steam generated by the ejector in the ejector tower enters the heat network water heater from the steam outlet of the ejector tower, and the steam exchanges heat with the heat network water in the heat network water heater to heat the heat network water.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the present invention, the steam after the steam turbine does work enters the ejector tower as the ejector gas, and the desulfurized slurry in the ejector tower is used as the fluid to be ejected. Through the ejector action generated by the high-speed flow of the steam turbine, the pressure of the desulfurized slurry is reduced, so that the boiling point of the liquid water in the desulfurized slurry is reduced and evaporated into gas. The evaporated gas is used to heat the heat network water, realizing the function of recovering the waste heat of the flue gas for daily heating. It avoids the direct contact between the flue gas and the heat exchanger during the waste heat recovery process of the flue gas, reducing the corrosion effect of the flue gas on the metal heat exchanger. The waste heat is recovered by the phase change method of ejector evaporation, avoiding the dew point limitation of the condensation of water in the flue gas during the direct heat exchange process, and further improving the degree of waste heat recovery of the flue gas.

[0019] Furthermore, by reducing the moisture content and temperature of the desulfurized slurry, the ability of the slurry in the wet desulfurization tower to remove sulfur from the flue gas, recover waste heat of the flue gas and moisture is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the system structure of the present invention.

[0021] Wherein: 1 - boiler; 2 - feed water pump; 3 - condenser; 4 - steam turbine; 5 - wet flue gas desulfurization tower; 6 - chimney; 7 - desulfurized slurry outlet pump; 8 - desulfurized slurry inlet pump; 9 - ejector tower; 10 - desulfurized slurry header; 11 - desulfurized slurry ejector; 12 - demister; 13 - heat network water heater. Specific embodiments

[0022] The present invention will be further described in detail below with reference to the accompanying drawings:

[0023] As Figure 1 shown, the desulfurized slurry heat extraction and water intake device using the steam extraction of the unit of the present invention includes a boiler 1, a feed water pump 2, a condenser 3, a steam turbine 4, a wet flue gas desulfurization tower 5, a chimney 6, a desulfurized slurry outlet pump 7, a desulfurized slurry inlet pump 8, an ejector tower 9, a desulfurized slurry header 10, a desulfurized slurry ejector 11, a demister 12 and a heat network water heater 13 in a coal-fired power generation unit.

[0024] The steam outlet of the boiler 1 is connected to the inlet of the steam turbine 4. The outlet of the steam turbine 4 is divided into two paths. One path is connected to the steam inlet of the ejector tower 9, and the other path is connected to the inlet of the condenser 3. The outlet of the condenser 3 is connected to the inlet of the water pump 2, and the outlet of the water pump 2 is connected to the water inlet of the boiler 1.

[0025] The flue gas outlet of the boiler 1 is connected to the flue gas inlet of the wet flue gas desulfurization tower 5, and the flue gas outlet of the wet flue gas desulfurization tower 5 is connected to the chimney 6.

[0026] The steam outlet of the ejector tower 9 is connected to the hot end of the heat network water heater 13, and the cold end of the heat network water heater 13 is connected to the heat network water.

[0027] The slurry outlet of the wet flue gas desulfurization tower 5 is connected to the slurry inlet of the ejector tower 9, and the slurry outlet of the ejector tower 9 is connected to the slurry inlet of the wet flue gas desulfurization tower 5. A desulfurized slurry outlet pump 7 is provided between the slurry outlet of the wet flue gas desulfurization tower 5 and the slurry inlet of the ejector tower 9, and a desulfurized slurry inlet pump 8 is provided between the slurry outlet of the ejector tower 9 and the slurry inlet of the wet flue gas desulfurization tower 5.

[0028] The ejector tower 9 is provided with a desulfurized slurry header 10, a desulfurized slurry ejector 11 and a demister 12. The desulfurized slurry ejector 11 is located above the desulfurized slurry header 10, and the demister 12 is located above the desulfurized slurry ejector 11. The desulfurized slurry header 10 is connected to the slurry inlet of the ejector tower 9, and the desulfurized slurry ejector 11 is connected to the outlet of the steam turbine 4.

[0029] The flue gas generated by the combustion of coal in the boiler 1 first enters the wet desulfurization tower 5 for desulfurization, and then enters the chimney 6 for emission; the extraction steam from the steam turbine 4 enters the desulfurization slurry ejector 11; the desulfurization slurry generated by the wet desulfurization tower 5 first enters the desulfurization slurry header 10 through the desulfurization slurry outlet pump 7, and the desulfurization slurry after being ejected and extracting water returns to the wet desulfurization tower 5 from the bottom of the ejector tower 9 through the desulfurization slurry inlet pump 8; the water vapor generated by the ejection in the ejector tower 9 enters the heat network water heater 13 from the upper part of the ejector tower 9.

[0030] During the operation of the generating unit, the boiler 1 uses the heat released by the combustion of coal to heat the liquid water coming from the feed water pump 2, turning it into high-temperature and high-pressure gas and entering the steam turbine 4. In the steam turbine 4, through work, its own pressure and temperature are further reduced, and then it enters the condenser 3 for condensation, becoming liquid water and starting a new cycle from the feed water pump 2. The flue gas generated by the combustion in the boiler 1 enters the wet desulfurization tower 5 for desulfurization after denitrification and dust removal. The desulfurization slurry coming out of the wet desulfurization tower 5 has a relatively high temperature and contains a large amount of water after absorbing the heat in the flue gas. It enters the slurry header 10 located in the ejector tower 9 through the desulfurization slurry outlet pump 7 and is distributed to each desulfurization slurry ejector 11 through the slurry header 10.

[0031] By extracting a part of the steam for the unit from the steam turbine 4 and entering the desulfurization slurry ejector 11 as the ejector fluid, using the high-speed airflow formed by the extraction steam of the unit in the desulfurization slurry ejector 11 to reduce the pressure of the surrounding entrained desulfurization slurry, so that the water vapor in the desulfurization slurry evaporates. The evaporated water vapor and the extraction steam of the unit enter the heat network water heater 13 along the upper part of the ejector tower 9, condense and heat the heat network water, thus realizing the recovery and utilization of the waste heat of the flue gas to the heat network water supply. The condensed water can also be used as makeup water for the generating unit or the heat network at the same time. The entrained desulfurization slurry enters the wet desulfurization tower 5 again from the lower part of the ejector tower 9 through the desulfurization slurry inlet pump to desulfurize the flue gas again.

[0032] The present invention can introduce the extraction steam of the unit into the desulfurization slurry ejector 11 as the ejector gas, use the desulfurization slurry coming from the wet desulfurization tower 5 as the entrained fluid, and through the entrainment effect generated by the high-speed flow of the extraction steam of the unit, reduce the pressure of the desulfurization slurry entering the desulfurization slurry ejector 11, so that the boiling point of the liquid water in the desulfurization slurry is reduced and evaporated into gas, and use the evaporated gas to heat the heat network water to realize the function of recovering the waste heat of the flue gas for daily life heating.

[0033] 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, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or make equivalent substitutions, and any modification or equivalent substitution that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A desulfurization slurry heat extraction and water intake device using the extraction steam of the unit, characterized in that It includes a boiler (1), a steam turbine (4), an ejector tower (9) and a heat network water heater (13); The steam outlet of the boiler (1) is connected to the inlet of the steam turbine (4), the outlet of the steam turbine (4) is connected to the steam inlet of the ejector tower (9), the steam outlet of the ejector tower (9) is connected to the hot end of the heat network water heater (13), and the cold end of the heat network water heater (13) is connected to the heat network water; The flue gas outlet of the boiler (1) is connected to the flue gas inlet of a wet desulfurization tower (5), and the flue gas outlet of the wet desulfurization tower (5) is connected to a chimney (6); The slurry outlet of the wet desulfurization tower (5) is connected to the slurry inlet of the ejector tower (9), and the slurry outlet of the ejector tower (9) is connected to the slurry inlet of the wet desulfurization tower (5); A desulfurization slurry header (10) and a desulfurization slurry ejector (11) are arranged in the ejector tower (9). The desulfurization slurry ejector (11) is located above the desulfurization slurry header (10). The desulfurization slurry header (10) is connected to the slurry inlet of the ejector tower (9), and the desulfurization slurry ejector (11) is connected to the outlet of the steam turbine (4).

2. The desulfurized slurry heat extraction and water intake device using the extraction steam of the unit according to claim 1, characterized in that, The outlet of the steam turbine (4) is divided into two paths. One path is connected to the steam inlet of the ejector tower (9), and the other path is connected to the inlet of a condenser (3). The outlet of the condenser (3) is connected to the water inlet of the boiler (1).

3. The desulfurized slurry heat extraction and water intake device using the extraction steam of the unit according to claim 2, wherein A water pump (2) is arranged between the outlet of the condenser (3) and the water inlet of the boiler (1).

4. The desulfurized slurry heat extraction and water intake device using the extraction steam of the unit according to claim 1, characterized in that, A desulfurization slurry outlet pump (7) is arranged between the slurry outlet of the wet desulfurization tower (5) and the slurry inlet of the ejector tower (9), and a desulfurization slurry inlet pump (8) is arranged between the slurry outlet of the ejector tower (9) and the slurry inlet of the wet desulfurization tower (5).

5. The desulfurized slurry heat extraction and water intake device using the extraction steam of the unit according to claim 1, wherein, A demister (12) is arranged in the ejector tower (9), and the demister (12) is located above the steam inlet of the ejector tower (9).

6. The working process of the desulfurization slurry heat extraction and water intake device using the extraction steam of the unit according to any one of claims 1-5, characterized in that, It includes the following processes: The boiler (1) uses the heat released by coal combustion to heat liquid water, turning it into a high-temperature and high-pressure gas and entering the steam turbine (4). After doing work in the steam turbine (4), it enters the ejector tower (9). The steam generated by ejection in the ejector tower (9) enters the heat network water heater (13) from the steam outlet of the ejector tower (9). The steam exchanges heat with the heat network water in the heat network water heater (13) to heat the heat network water.

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