CN204438718U - Residual heat from boiler fume drying brown coal system and boiler smoke system - Google Patents

Abstract

The utility model discloses a boiler flue gas waste heat drying lignite system and a boiler flue gas system; the boiler flue gas waste heat drying lignite system comprises a flue gas-circulating water heat exchanger, an air-circulating water heat exchanger, a drying gas Fan, lignite drying tower, coal feeder and discharger; the boiler flue gas system includes economizer, air preheater, dry electrostatic precipitator, flue gas induced draft fan, desulfurization absorption tower, wet electrostatic precipitator and The boiler flue gas waste heat drying lignite system. The utility model utilizes the heat in the flue gas of the boiler to the greatest extent, improves the coal-fired quality of the lignite-burning unit, improves the efficiency of the boiler, and makes the flue gas discharge reach an ultra-clean level.

Description

Boiler flue gas waste heat drying lignite system and boiler flue gas system

technical field

The utility model relates to a flue gas treatment system of a coal-fired power plant, in particular to a boiler flue gas waste heat drying lignite system and a boiler flue gas system.

Background technique

For thermal power plants, the largest boiler heat loss is exhaust heat loss. Generally speaking, every time the exhaust gas temperature decreases by 10°C, the thermal efficiency of the boiler increases by about 0.5% to 0.6%. Therefore, boiler exhaust gas is a waste heat resource with great potential. At present, most of the flue gas systems of new large-scale thermal power generation units have canceled the GGH system, which makes the temperature of the flue gas entering the desulfurization system relatively high, generally around 130 °C, and the lignite unit may reach 145 °C. In order to achieve the best working temperature for the desulfurization process, that is, the flue gas temperature is 80°C to 90°C. At present, many new desulfurization systems are equipped with spray cooling systems. It can be seen that the temperature difference of tens of degrees between the flue gas temperature entering the desulfurization system and the optimal desulfurization working temperature contains huge heat, which is wasted in this way. Therefore, it is very necessary to recover and utilize the waste heat of this part of the flue gas.

Utility model content

In view of this, the purpose of this utility model is to provide a boiler flue gas waste heat drying lignite system and a boiler flue gas system, use the boiler flue gas waste heat to dry the high-moisture lignite used in power plants, and increase the low calorific value of the furnace coal (increase quality of coal fired), improve boiler efficiency.

In order to achieve the above object, the utility model provides the following technical solutions:

The utility model discloses a boiler flue gas waste heat drying lignite system, which comprises a flue gas-circulating water heat exchanger, an air-circulating water heat exchanger, a drying gas induced draft fan, a lignite drying tower, a coal feeder and a discharger. The flue gas-circulating water heat exchanger is arranged in the tail flue of the boiler, the circulating water pipe of the air-circulating water heat exchanger communicates with the circulating water pipe of the flue gas-circulating water heat exchanger, and the lignite drying tower The air inlet pipe at the lower part communicates with the air-circulating water heat exchanger, the air outlet pipe at the upper part of the lignite drying tower communicates with the boiler furnace through the dry gas induced draft fan, and the coal feeder communicates with the coal inlet at the top of the lignite drying tower , the discharge machine communicates with the coal outlet at the bottom of the lignite drying tower.

In the above technical solution, both the flue gas-circulating water heat exchanger and the air-circulating water heat exchanger are tubular heat exchangers, and the circulating water pipes and the air-circulating water of the flue gas-circulating water heat exchanger The circulating water pipes of the heat exchanger are the tube-side channels of the tubular heat exchanger.

In the above technical solution, both the coal feeder and the discharger are belt conveyors.

The utility model also discloses a boiler flue gas system comprising the boiler flue gas waste heat drying lignite system, including an economizer, an air preheater, a dry electrostatic precipitator, a flue gas induced draft fan, a desulfurization absorption tower, a wet type The electrostatic precipitator and the boiler flue gas waste heat drying lignite system, the economizer, the air preheater and the dry electrostatic precipitator are sequentially arranged in the tail flue of the boiler from upstream to downstream, and the dry electrostatic precipitator The outlet communicates with the lower part of the desulfurization absorption tower through the flue gas induced fan, the upper part of the desulfurization absorption tower communicates with the inlet of the wet electrostatic precipitator, and the outlet of the wet electrostatic precipitator communicates with the chimney.

As a further improvement of the utility model, the number of flue gas-circulating water heat exchangers in the boiler flue gas waste heat drying lignite system is two, and the two flue gas-circulating water heat exchangers are connected in series and are respectively located in the dry electrostatic precipitator upstream and downstream of the device.

The beneficial effects of the utility model are:

The utility model utilizes the residual heat of boiler flue gas to dry the high-moisture lignite used in the power plant, utilizes the heat in the boiler flue gas to the greatest extent, improves the coal quality of the units burning lignite, and improves the efficiency of the boiler; the utility model fully Combined with the concept of "energy graded utilization", low-grade heat energy is used to improve the quality of high-grade energy, and at the same time, it enriches the way to utilize flue gas waste heat. At the same time, the utility model is equipped with efficient flue gas treatment equipment in the flue gas system, so that the flue gas emission of the main system can reach an ultra-clean level. The utility model can be applied to newly-built or reformed flue gas systems of large and medium-sized coal-fired heat-supply power plants, and can achieve higher safety, economic and environmental benefits.

Description of drawings

In order to make the purpose, technical solutions and beneficial effects of the utility model clearer, the utility model provides the following drawings for illustration:

Fig. 1 is the structural representation of the utility model.

In the figure: 1. Flue gas-circulating water heat exchanger, 2. Air-circulating water heat exchanger, 3. Dry gas induced draft fan, 4. Lignite drying tower, 5. Coal feeder, 6. Discharge machine, 7 , Boiler furnace, 8. Economizer, 9. Air preheater, 10. Dry electrostatic precipitator, 11. Flue gas induced draft fan, 12. Desulfurization absorption tower, 13. Wet electrostatic precipitator.

Detailed ways

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

Fig. 1 is a schematic structural view of the utility model, as shown in the figure, the boiler flue gas waste heat drying lignite system includes a flue gas-circulating water heat exchanger 1, an air-circulating water heat exchanger 2, a drying gas induced draft fan 3, and a lignite drying Tower 4, coal feeder 5 and discharger 6, the flue gas-circulating water heat exchanger 1 is arranged in the tail flue of the boiler, the circulating water pipe of the air-circulating water heat exchanger 2 is connected with the flue gas-circulating The circulating water pipeline of the water heat exchanger 1 is connected, the air inlet pipeline at the bottom of the lignite drying tower 4 is connected with the air-circulating water heat exchanger 2, and the air outlet pipeline at the upper part of the lignite drying tower 4 is passed through the drying air induced draft fan 3 It communicates with the boiler furnace 7, the coal feeder 5 communicates with the coal inlet at the top of the lignite drying tower 4, and the discharger 6 communicates with the coal outlet at the bottom of the lignite drying tower 4.

Boiler flue gas system, including economizer 8, air preheater 9, dry electrostatic precipitator 10, flue gas induced draft fan 11, desulfurization absorption tower 12, wet electrostatic precipitator 13 and the boiler flue gas waste heat drying lignite system , the economizer 8, the air preheater 9 and the dry electrostatic precipitator 10 are sequentially arranged in the tail flue of the boiler from upstream to downstream, and the outlet of the dry electrostatic precipitator 10 passes through the flue gas induced draft fan 11 and the desulfurization The lower part of the absorption tower 12 communicates, the upper part of the desulfurization absorption tower 12 communicates with the inlet of the wet electrostatic precipitator 13, the outlet of the wet electrostatic precipitator 13 communicates with the chimney, and the flue gas-circulation of the boiler flue gas waste heat drying lignite system There are two water heat exchangers 1, and the two flue gas-circulating water heat exchangers 1 are connected in series and located upstream and downstream of the dry electrostatic precipitator 10 respectively.

Both the flue gas-circulating water heat exchanger 1 and the air-circulating water heat exchanger 2 are tubular heat exchangers, and the circulating water pipeline of the flue gas-circulating water heat exchanger 1 exchanges heat with the air-circulating water The circulating water pipes of the device 2 are the tube-side passages of the tubular heat exchanger.

Both the coal feeder 5 and the discharger 6 are belt conveyors.

When the flue gas system is running, the flue gas-circulating water heat exchanger 1 is used to exchange heat between the boiler flue gas and the circulating water, reducing the boiler flue gas from 140°C to about 80°C required by the desulfurization inlet, and reducing the heat loss of the boiler by 60°C. The conversion efficiency of the boiler can be increased by about 5%; the circulating water pipe of the flue gas-circulating water heat exchanger 1 and the circulating water pipe of the air-circulating water heat exchanger 2 form a closed loop, and the closed circulating water is used to turn the boiler The heat recovered in the flue gas is used to heat the hot air used for drying high-moisture lignite; the hot air is introduced into the lower part of the airtight lignite drying tower 4, and then the hot air passes through the lignite drying tower 4 from bottom to top to dry the lignite, and then passes through the drying air induced draft fan 3 to contain Part of the air of coal dust and coal volatile powder is drawn out, and finally sent to the boiler hot secondary air duct, enters the boiler furnace 7, and participates in boiler combustion; the raw coal is fed into the lignite drying tower 4 through the top coal feeder 5, and after being dried by hot air, The discharge machine 6 that falls into the bottom is sent into the raw coal hopper of the boiler. At the same time, after the boiler flue gas passes through the economizer 8 and the air preheater 9 to reduce the temperature of the flue gas, it not only reduces the specific resistance of the dust, but also reduces the volume of the flue gas, and increases the ratio of the dry electrostatic precipitator 10 in disguise. The dust collection area is desulfurized through the desulfurization absorption tower 12 with high efficiency, so that the SO ₂ is below 10mg/Nm ³ , and finally the dust emission concentration is controlled below 5 mg/Nm ³ through the wet electrostatic precipitator 13, and discharged through the chimney.

Finally, it is noted that the above preferred embodiments are only used to illustrate the technical solutions of the present utility model without limitation. Although the utility model has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in the form Various changes can be made to it in the aspects and details without departing from the scope defined by the claims of the present invention.

Claims (5)

1. A boiler flue gas waste heat drying lignite system, characterized in that it includes a flue gas-circulating water heat exchanger (1), an air-circulating water heat exchanger (2), a drying gas induced draft fan (3), and lignite drying Tower (4), coal feeder (5) and discharger (6), the flue gas-circulating water heat exchanger (1) is arranged in the tail flue of the boiler, and the air-circulating water heat exchanger (2 ) is connected with the circulating water pipe of the flue gas-circulating water heat exchanger (1), and the air inlet pipe at the lower part of the lignite drying tower (4) is connected with the air-circulating water heat exchanger (2). The air outlet pipe at the upper part of the lignite drying tower (4) communicates with the boiler furnace (7) through the dry gas induced draft fan (3), and the coal feeder (5) communicates with the coal inlet at the top of the lignite drying tower (4), The discharger (6) communicates with the coal outlet at the bottom of the lignite drying tower (4). 2. The boiler flue gas waste heat drying lignite system according to claim 1, characterized in that: the flue gas-circulating water heat exchanger (1) and the air-circulating water heat exchanger (2) are both tubular heat exchangers The heat exchanger, the circulating water pipeline of the flue gas-circulating water heat exchanger (1) and the circulating water pipeline of the air-circulating water heat exchanger (2) are all tube-side passages of the tubular heat exchanger. 3. The boiler flue gas waste heat drying lignite system according to claim 1, characterized in that: the coal feeder (5) and the discharger (6) are both belt conveyors. 4. The boiler flue gas system comprising the boiler flue gas waste heat drying lignite system according to any one of claims 1 to 3, characterized in that it includes an economizer (8), an air preheater (9), a dry electrostatic Dust collector (10), flue gas induced draft fan (11), desulfurization absorption tower (12), wet electrostatic precipitator (13) and the boiler flue gas waste heat drying lignite system, the economizer (8), air pre Heater (9) and dry electrostatic precipitator (10) are sequentially arranged in the tail flue of the boiler from upstream to downstream. (12) The lower part communicates, the upper part of the desulfurization absorption tower (12) communicates with the inlet of the wet electrostatic precipitator (13), and the outlet of the wet electrostatic precipitator (13) communicates with the chimney. 5. The boiler flue gas system according to claim 4, characterized in that: the number of flue gas-circulating water heat exchangers (1) in the boiler flue gas waste heat drying lignite system is two, and two flue gas-circulating The water heat exchangers (1) are connected in series and are respectively located upstream and downstream of the dry electrostatic precipitator (10).