CN105944495A - Coal-fired flue gas deep purification smoke plume removing system - Google Patents

Abstract

The invention provides a smoke plume removal system for deep purification of coal-fired flue gas, which can be used to treat flue gas after wet flue gas desulfurization and eliminate white smoke and rain. The system mainly includes a cooling phase-change coalescer, a flue demister and a warmer arranged in the flue after desulfurization in sequence. Discharge through the chimney after treatment. Compared with the existing conventional method of directly heating up the flue gas to slow down the white smoke from the chimney, the smoke elimination in the coal-fired flue gas deep purification plume removal system adopts a small temperature drop, dehydration and then a small temperature rise method, which not only promotes multi-pollution It also has obvious energy-saving advantages, and at the same time realizes the real smoke elimination.

Description

Coal-fired flue gas deep purification smoke plume removal system

Technical field:

The invention provides a smoke plume removal system for deep purification of coal-fired flue gas, which belongs to the field of resource and environment flue gas purification.

Background technique:

As environmental protection requirements become more and more stringent, China's coal-fired power plants are required to achieve ultra-low emission limits for air pollutants (the emission concentrations of NOx, SO ₂ , and dust are required to be controlled at 50 mg/m ³ , 35 mg/m ³ , and 10 mg/m 3 , respectively. / ^m3 ), and some areas (such as Shanghai, Zhejiang, etc.) require control measures to eliminate the phenomenon of gypsum rain and colored smoke rain in the chimney after desulfurization, so that the chimney does not emit white smoke.

For the elimination of white smoke, the current conventional method is to directly increase the flue gas reheater, which greatly increases the flue gas temperature, high energy consumption for operation, and increased coal consumption for power generation, which is not conducive to energy saving in production. In addition, a large number of gypsum-containing mist droplets carried in the flue gas also form secondary particulate matter emissions due to heating and evaporation, resulting in secondary pollution. The water in the flue gas is directly discharged into the atmosphere and lost, which is not conducive to water conservation. Therefore, it is particularly important to develop a coal-fired flue gas deep purification plume removal system device to achieve low energy consumption, water saving, no secondary pollution, and can successfully solve the slurry carry and eliminate white smoke.

Invention content:

The invention provides a coal-fired flue gas deep purification smoke plume removal system, which is used for further processing the desulfurized flue gas to meet the requirements of further deep purification, emission reduction and smoke elimination.

The concrete technical scheme that the present invention adopts is as follows:

A coal-fired flue gas deep purification smoke plume removal system, mainly including a cooling phase-change coalescer, a flue demister and a heater arranged in sequence in the flue after desulfurization, and the flue gas at the outlet of the desulfurization tower is sequentially cooled and phase-changed After being treated by the coalescer, the flue demister and the heater, it is discharged through the chimney.

It is also equipped with a flushing system, which includes a pump, flushing pipeline and nozzles, and is used to clean the cooling phase change condenser, flue demister and heater.

It is also equipped with a drainage system, which adopts the structure of drainage tanks on both sides of the flue demister, and the drainage tanks are connected with the degassing tower or the slurry preparation system.

The cooling phase change condenser mainly includes a metal shell, an inner anti-corrosion layer and a heat exchange pipeline. The heat exchange cold source comes from a separate air cooling or water cooling system, or a separate electric drive or ground source heat pump refrigeration system, which is generally preferred The open water cooling system simply filters incoming water from the power plant and passes it through the cooling phase-change condenser before supplying it to other facilities, without affecting other water used in the power plant.

The heater mainly includes a metal shell, an inner anti-corrosion layer and a heat exchange pipeline. The heat exchange heat source comes from the waste heat recovery of the flue gas system or other available heat sources to reduce energy consumption.

The working process of the coal-fired flue gas deep purification plume removal system device of the present invention is as follows:

First, the flue gas at the outlet of the desulfurization tower is cooled by 0.1-10°C (normal temperature drop within 3°C) through the phase-cooled phase-change condenser, condensed, defogged, and dust-removed, and the treated flue gas enters the flue demister;

Second, the remaining mist and particles in the flue gas are further captured through the flue demister, and then the flue gas is sent to the heater;

Third, the heater heats up the flue gas by 0.1-10°C (required to be 0.5-3°C higher than the saturation temperature of the contained water vapor), making it unsaturated flue gas and discharging it through the chimney.

Also includes the following steps:

The surface of the cooling phase change condenser, flue demister and warmer is regularly flushed by the flushing system, and the flushing water and condensed water in the flue are returned to the absorption tower or sent to the slurry preparation system through the drain system.

The heat exchange pipeline of the phase change condenser and the reheater realizes heat exchange through the heat exchange medium, and the heat exchange medium can be water, oil, etc.

Compared with the prior art, the present invention has the following advantages:

In the present invention, the cooling phase change condenser is used to lower the temperature of the flue gas by 0.1-10°C, so that the saturated and supersaturated water vapor in the flue gas condenses and precipitates, and at the same time, the fine mist droplets and fine particles in the flue gas undergo phase change and condense to grow and condense , and the precipitated water droplets collide with the tube wall and are captured to achieve the purpose of dust removal and mist removal.

In the present invention, the flue gas demister is used for further purification of the flue gas. After cooling the water vapor in the flue of the phase change condenser is cooled by 2 to 10°C, a large number of mist droplets are condensed and gradually grow up, and at the same time, the water vapor in the flue gas is gradually infiltrated. The phase change condenses the fine particles that have been agglomerated, but only part of them is intercepted by the cooling phase change agglomerator, and the addition of a flue demister helps to further remove the other part of mist and particles.

In the present invention, the warmer is used to raise the temperature of the flue gas after passing through the first two facilities by 2 to 10°C. The temperature needs to be determined in combination with the ambient temperature and the local atmospheric pressure. The flue gas can be slightly reheated by the heater to make the flue gas dry, and the white smoke can be eliminated by discharging the chimney.

In the present invention, the flushing and water-repellent system flushes the three facilities, the nozzles are arranged to cover all sections of the facilities, the flushing method adopts gap operation, and pressure gauges are installed before and after each facility to monitor the change of resistance. Drainage tanks are set on both sides of the flue demister to recover the condensed water and flushing water in the flue and return them to the absorption tower or slurry preparation system.

The smoke plume removal method of the present invention is as follows: first, the supersaturated water vapor of the flue gas and the carried gypsum droplets are condensed and grown up by cooling the phase change condenser, and then further removed by the flue demister to remove the dehydrated plume. Flue gas reheating only needs to consume a small amount of heat to become unsaturated flue gas, and no white smoke will be produced when discharged. The principle of eliminating white smoke is to remove the water in the saturated or supersaturated flue gas, and when the flue gas is discharged to the environment, it will become unsaturated flue gas, that is, no white smoke will be produced.

Description of drawings:

Figure 1 is a schematic diagram of the method of the present invention.

In the figure: 1-cooling phase change condenser; 2-flue demister; 3-heater; 4-hydrophobic tank.

detailed description:

Below in conjunction with accompanying drawing, the present invention will be further described:

Embodiment one:

As shown in Figure 1, the coal-fired flue gas deep purification plume removal system of the present invention mainly includes four parts, namely, a cooling phase change coalescer 1, a flue demister 2, Heater 3 and corresponding flushing and drainage system.

According to the positional relationship of each part, the flue gas at the outlet of the desulfurization tower is processed by the cooling phase change condenser 1, the flue demister 2 and the warmer 3 in turn, and then discharged through the chimney.

The flushing system includes a pump, a flushing pipeline and a nozzle, and is used for cleaning the cooling phase change condenser 1, the flue demister 2 and the heater 3.

The drainage system adopts the structure of drainage grooves on both sides of the flue demister, and the drainage groove 4 is connected with the de-flow tower or the slurry preparation system.

The cooling phase-change condenser 1 mainly includes a metal shell, an inner lining anti-corrosion layer and a heat exchange pipeline. The heater 3 mainly includes a metal shell, an inner anti-corrosion layer and a heat exchange pipeline. The heat exchange pipelines of the two are made of fluoroplastic or metal material with better thermal conductivity.

Embodiment two:

The collaborative purification method for ultra-low emission of flue gas and smoke elimination of the present invention includes the following treatment process:

First, the flue gas at the outlet of the desulfurization tower is cooled by 3°C through the cooling phase change condenser, condensed, demisted, and dust-removed, and the treated flue gas enters the flue demister;

Second, the remaining mist and particles in the flue gas are further captured through the flue demister, and then the flue gas is sent to the heater;

Third, the heater heats up the flue gas by 2°C to become unsaturated flue gas, which is discharged through the chimney.

Fourth, the surface of the cooling phase change condenser, flue demister and warmer is regularly flushed by the flushing system, and the flushed water and condensed water in the flue are returned to the absorption tower or sent to the slurry preparation system through the drainage system .

Application example one:

The device system of the present invention is installed after a flue gas desulfurization device with a flue gas treatment capacity of 50,000 m ³ /h, in which the cooling phase change coagulant and the warmer are equipped with heat transfer medium (water) delivery pumps, and the cooling phase change condensing The cooling medium of the heater is open cooling water (no need to calculate the cooling energy consumption, only the power consumption of the delivery pump is counted), the heating medium of the heater is external hot water (the heat is included in the energy consumption statistics), and the opening control of each facility of the device of the present invention The conditions and effects are shown in the test table below, and the situation of test 1 is similar to the current way of direct heating to eliminate white smoke, only the flue demister and heater are put into operation. Test 2 is the smoke elimination method of the device of the present invention, and the cooling phase change coalescer, the flue demister and the heater are all put into operation. It can be seen that the energy consumption of the system of the present invention can save 45.7% of energy consumption compared with the traditional method of directly heating flue gas, and can promote the reduction of multi-pollutant emissions. Because the test device equipment is old equipment, the energy consumption conversion provided in Table 1 is only used for this purpose. The comparison of the same input conditions between the invention and the traditional method is not used as the basis for energy consumption calculation of industrial amplified data.

surface 1

Claims (5)

1. a multifunction burning flue-gas deep purifying plume removes system and device, it is characterized in that: mainly include cooling phase-change knockouts, flue demister and the warmer being sequentially arranged in desulfurization rear pass, through smoke stack emission after desulfurizing tower exiting flue gas the most cooled phase transformation knockouts, flue demister and warmer process.

The most according to claim 1, coal-fired flue-gas multifunction depth purifies smoke consuming apparatus, it is characterised in that: being also configured with rinse-system, this system includes water pump, flushing line and nozzle, for being carried out cooling phase-change knockouts, flue demister and warmer.

The most according to claim 2, multifunction burning flue-gas deep purifying plume removes system and device, it is characterized in that: be also configured with draining system, this system uses the semicircle drain tank version in flue demister both sides, drain tank connects with desulfurizing tower or serum producing system, and the condensation water of recovery and flushing water enter desulphurization system and utilize.

4. according to claim 1-3 arbitrary described multi-functional minimum discharge water saving smoke elimination cooperated purification system, it is characterised in that: cooling phase-change knockouts mainly includes metal shell, inside lining anti-corrosive layer and heat exchanging pipe.

5. remove system and device according to the arbitrary described multifunction burning flue-gas deep purifying plume of claim 1-3, it is characterised in that: warmer mainly includes metal shell, inside lining anti-corrosive layer and heat exchanging pipe.