CN211119603U - A system for indirect heating of flue gas with low temperature waste heat and water supply for heating network - Google Patents

Abstract

The utility model provides a flue gas low temperature waste heat indirect heating heat supply network water charging system, including coal fired boiler, dust remover, wet flue gas desulfurization tower, flash column, ejector, steam turbine and heat supply network heater, wherein, coal fired boiler's flue gas outlet is connected the entry of dust remover, and the bottom entry of wet flue gas desulfurization tower is connected to the export of dust remover, and the bottom desulfurization thick liquid export of wet flue gas desulfurization tower is connected with the entry of flash column; the top of the wet desulphurization tower is provided with a clean flue gas outlet; a cold slurry outlet of the flash tower is connected with a cold slurry inlet at the top of the wet desulphurization tower; a negative pressure steam outlet of the flash tower is connected with an inlet of an ejector, a heat supply network water replenishing inlet is arranged on the ejector, an outlet of the ejector is connected with an inlet of a heat supply network heater, and a heat supply network water supply outlet is arranged on the heat supply network heater; a steam outlet of the coal-fired boiler is connected with an inlet of a steam turbine, and a steam extraction port arranged in the middle of the steam turbine is connected with a heat supply network heater; the utility model discloses simple structure can improve energy efficiency, increases unit heating capacity, has apparent economic benefits.

Description

A system for indirect heating of flue gas with low temperature waste heat and water supply for heating network

technical field

The utility model belongs to the field of energy saving and emission reduction of thermal power generation, in particular to a water supply system for indirect heating and heating network of flue gas low temperature waste heat.

Background technique

The smoke loss of coal-fired cogeneration units accounts for a considerable proportion of the fuel calorific value, reducing the smoke loss and effectively improving the energy utilization efficiency of the unit. At present, the waste heat recovery of flue gas mainly adopts the method of partition heat exchanger. Since coal-fired flue gas contains ash and acid gas, it is easy to cause wear and corrosion of the heat exchanger, and the reliability of the equipment is generally poor.

Most of the wet desulfurization towers of coal-fired cogeneration units are close to the critical point of water balance. The low temperature economizer technology to reduce flue gas temperature and the flue evaporation technology of desulfurization wastewater are often used, which will aggravate the water balance problem of wet desulfurization towers. As a result, the desulfurization tower cannot work properly.

The wet desulfurization slurry is flashed, and the desulfurized slurry is introduced into the flash tower in the negative pressure state. The flashing process occurs, and a large amount of negative pressure flash steam is generated. The negative pressure flash steam passes through the condenser or heat pump and other equipment to complete the condensation and heat release, which can realize the recovery and utilization of heat, and the moisture formed by the condensation of water vapor can effectively reduce the overall water consumption of the unit. The flue gas is sprayed with the cooled desulfurization slurry to reduce the temperature and water content of the flue gas, and to eliminate the visual pollution of white plumes.

The hot water supply with a certain pressure from the jet pump enters the nozzle through the water chamber, the nozzle converts the pressure energy of the pressurized water into velocity energy, and the water flow is ejected from the nozzle at a high speed, so that the negative pressure flash steam is sucked into the chamber to generate a high vacuum and pumped out. The flash steam in the flash tower, the flash steam and the heating network make-up water are mixed and condensed into the diffusion pipe together.

However, the existing heating network heating does not utilize the high temperature flue gas of the coal-fired cogeneration unit, resulting in waste of resources.

SUMMARY OF THE INVENTION

The purpose of the utility model is to provide a system for indirectly heating the heat network water supply by low-temperature waste heat of flue gas, which indirectly recovers the waste heat of flue gas after wet desulfurization, reduces the amount of water supply in the heat network, solves the problem of water balance in the desulfurization tower, and simultaneously reduces the amount of water in the flue gas. Vapor content, eliminate the visual pollution phenomenon of white plume.

In order to achieve the above-mentioned purpose, the technical scheme that the utility model adopts is:

The utility model provides a flue gas low-temperature waste heat indirect heating heating network water supply system, which includes a coal-fired boiler, a dust collector, a wet desulfurization tower, a flash tower, an ejector, a steam turbine and a heating network heater. The flue gas outlet of the boiler is connected to the inlet of the dust collector, the outlet of the dust collector is connected to the bottom inlet of the wet desulfurization tower, and the desulfurization slurry outlet of the bottom of the wet desulfurization tower is connected to the inlet of the flash tower; the top of the wet desulfurization tower is provided with a clean smoke outlet;

The cold slurry outlet of the flash tower is connected with the cold slurry inlet of the top of the wet desulfurization tower;

The negative pressure steam outlet of the flash tower is connected to the inlet of the ejector. The ejector is provided with a water supply inlet for the heating network. The outlet of the ejector is connected to the inlet of the heating network heater. The heating network heater is provided with a heating network water supply outlet. ;

The steam outlet of the coal-fired boiler is connected to the inlet of the steam turbine, and the steam extraction port set in the middle of the steam turbine is connected to the heating network heater.

Preferably, an induced draft fan is provided between the outlet of the dust collector and the bottom inlet of the wet desulfurization tower.

Preferably, a first slurry pump is provided between the bottom desulfurization slurry outlet of the wet desulfurization tower and the inlet of the flash tower.

Preferably, the flue gas outlet at the top of the wet desulfurization tower is connected with a chimney.

Preferably, a second slurry pump is provided between the cold slurry outlet of the flash tower and the cold slurry inlet of the top of the wet desulfurization tower.

Preferably, a water pump is provided at the water supply inlet of the heat network on the ejector.

Preferably, a water mixer is provided between the outlet of the ejector and the inlet of the heating network heater.

Compared with the prior art, the beneficial effects of the present utility model are:

The utility model provides a flue gas low-temperature waste heat indirect heating heating network water supply system, which can recover the heat of the desulfurization slurry in the wet desulfurization tower, indirectly achieve the purpose of deep recovery of the flue gas waste heat, improve the energy utilization efficiency, and increase the heating capacity of the unit , has significant economic benefits; at the same time, a large amount of water vapor can be extracted from the desulfurization slurry by flash evaporation, and the condensate water formed after the condensation of water vapor is of good quality, which is directly used as supplementary water for the heat network to reduce water consumption in the power plant; through flash evaporation After a large amount of water vapor is extracted from the desulfurization slurry, the problem of water balance in the desulfurization tower is solved, and equipment failures caused by the expansion of the desulfurization tower are avoided; after the desulfurization slurry is flashed, the evaporative cooling of the desulfurization slurry is realized, and the cold slurry After spraying the flue gas, the temperature and moisture content of the flue gas leaving the desulfurization tower can be greatly reduced, and the purpose of eliminating the visual pollution of the white plume is realized; the system has a simple structure and low investment.

Description of drawings

FIG. 1 is a schematic diagram of the system structure involved in the present invention.

Detailed ways

The present utility model will be further described in detail below in conjunction with the accompanying drawings.

As shown in Figure 1, the utility model provides a flue gas low-temperature waste heat indirect recovery heating heating network water supply device, including a coal-fired boiler 1, a dust collector 2, an induced draft fan 3, a wet desulfurization tower 4, and a first slurry pump 5 , flash tower 6, second slurry pump 7, chimney 8, ejector 9, water pump 10, water mixer 11, steam turbine 12 and heat network heater 13, wherein the flue gas outlet of coal-fired boiler 1 is connected to a dust collector 2, the outlet of the dust collector 2 is connected to the inlet of the induced draft fan 3, the outlet of the induced draft fan 3 is connected to the bottom inlet of the wet desulfurization tower 4, and the desulfurization slurry outlet of the bottom of the wet desulfurization tower 4 passes through the first slurry pump 5 and flash evaporation. The inlet of the tower 6 is connected; the flue gas at the top of the wet desulfurization tower 4 is connected to the chimney 8.

The cold slurry outlet of the flash tower 6 is connected to the cold slurry inlet of the top of the wet desulfurization tower 4 through the second slurry pump 7 .

The negative pressure steam outlet of the flash tower 6 is connected to the steam inlet of the ejector 9, the outlet of the ejector 9 is connected to the inlet of the water mixer 11, the outlet of the water mixer 11 is connected to the inlet of the heating network heater 13, and the heating network heating The outlet of the device 13 is connected to the heating network water supply equipment.

The ejector 9 is provided with a water supply inlet for the heating network, and the water supplying inlet for the heating network is connected with an external device for supplying water for the heating network; a water pump 10 is arranged at the water supplying inlet for the heating network.

The steam outlet of the coal-fired boiler 1 is connected to the inlet of the steam turbine 12 , and the steam extraction port provided in the middle of the steam turbine 12 is connected to the heating network heater 13 .

The system workflow:

The flue gas generated by the coal-fired boiler 1 passes through the dust collector 2, and then is sent to the wet desulfurization tower 4 by the induced draft fan 3. The flue gas in the wet desulfurization tower 4 undergoes a desulfurization reaction with the desulfurization slurry sprayed from the top, and the temperature is lowered at the same time. Humidification; the desulfurization slurry at the bottom outlet of the wet desulfurization tower 4 is sent to the flash tower 6 through the first slurry pump 5, and the desulfurization slurry in the flash tower 6 undergoes an evaporative cooling process, and flashes out negative pressure steam, and simultaneously cools down to become a cold slurry, The cold slurry is sent to the wet desulfurization tower 4 through the second slurry pump 7, and is sprayed into the tower from the top. After spraying and desulfurization reaction, the flue gas passes through the demister, leaves the wet desulfurization tower 4, and is sent to the chimney 8. into the atmosphere.

The heating network make-up water is sent to the ejector 9 through the water pump 10, and negative pressure is generated in the ejector 9. The negative pressure steam generated by the flash tower 6 enters the ejector 9 under the action of the pressure difference, and is condensed after mixing with the heating network make-up water. , into the mixer 11.

The return water of the heating network is sent to the heating network heater 13 after passing through the water mixer 11, and the steam generated by the coal-fired boiler 1 is sent to the steam turbine 12 to generate electricity. After the heating network returns to the water, it is sent to the factory area.

Claims (7)

1. A flue gas low-temperature waste heat indirect heating heating network replenishment system, characterized in that, comprising a coal-fired boiler (1), a dust collector (2), a wet desulfurization tower (4), a flash tower (6), an ejector (9), steam turbine (12) and heat network heater (13), wherein the flue gas outlet of the coal-fired boiler (1) is connected to the inlet of the dust collector (2), and the outlet of the dust collector (2) is connected to the wet desulfurization The bottom inlet of the tower (4), the bottom desulfurization slurry outlet of the wet desulfurization tower (4) is connected with the inlet of the flash tower (6); the top of the wet desulfurization tower (4) is provided with a clean flue gas outlet; The cold slurry outlet of the flash tower (6) is connected with the cold slurry inlet at the top of the wet desulfurization tower (4); The negative pressure steam outlet of the flash tower (6) is connected to the inlet of the ejector (9), the ejector (9) is provided with a water supply inlet for the heating network, and the outlet of the ejector (9) is connected to the heating network heater (13). ) entrance, the heating network heater (13) is provided with a heating network water supply outlet; The steam outlet of the coal-fired boiler (1) is connected to the inlet of the steam turbine (12), and the steam extraction port provided in the middle of the steam turbine (12) is connected to the heating network heater (13). 2. A flue gas low-temperature waste heat indirect heating heating network water replenishing system according to claim 1, characterized in that, between the outlet of the dust collector (2) and the bottom inlet of the wet desulfurization tower (4), a The induced draft fan (3). 3. a kind of flue gas low-temperature waste heat indirect heating heat network replenishment system according to claim 1, is characterized in that, the bottom desulfurization slurry outlet of described wet desulfurization tower (4) and the entrance of flash tower (6) are between A first slurry pump (5) is arranged between. 4. A flue gas low-temperature waste heat indirect heating heat network replenishment system according to claim 1, characterized in that, the flue gas outlet at the top of the wet desulfurization tower (4) is connected with a chimney (8). 5. A kind of flue gas low-temperature waste heat indirect heating heating network water supply system according to claim 1, characterized in that the cold slurry outlet of the flash tower (6) and the cold slurry at the top of the wet desulfurization tower (4) A second slurry pump (7) is arranged between the inlets. 6 . The indirect heating and water supply system for heat network with low temperature waste heat of flue gas according to claim 1 , wherein a water pump ( 10 ) is provided at the water supply inlet of the heat network on the ejector ( 9 ). 7 . 7. A flue gas low-temperature waste heat indirect heating heating network water supply system according to claim 1, characterized in that, between the outlet of the ejector (9) and the inlet of the heating network heater (13) is provided with a Water mixer (11).

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