CN212999247U - Phase-change mixed-flow type air cooling and whitening system - Google Patents

Abstract

The utility model discloses a white system that disappears of phase transition mixed flow formula air-cooling, including plate heat exchanger, plate heat exchanger's hot air stream import and flue gas inflow pipe are linked together, and plate heat exchanger's hot air stream export communicates with each other through the bottom of flue gas outflow pipe with the chimney, plate heat exchanger's cold air stream import and plate heat exchanger's cold air stream export are equallyd divide into high temperature section and low temperature section, and plate heat exchanger's cold air stream import high temperature section is connected with centrifugal fan through first air inflow pipe, and plate heat exchanger's cold air stream export high temperature section communicates with each other through the middle part of air outflow pipe with the chimney, just the inside of chimney lies in the junction fixed mounting of air outflow pipe and chimney has the deep bead, and the inside of chimney lies in the top of deep bead and. The utility model discloses only utilize the high temperature section air, it is few to mix the amount of wind, and whole technology transformation range is little, and chimney and relevant pipeline transformation investment cost are reasonable relatively.

Description

Phase-change mixed-flow type air cooling and whitening system

Technical Field

The utility model relates to a flue gas disappears white technical field, concretely relates to phase transition mixed-flow forced air cooling and disappears white system.

Background

With the increasingly severe environmental protection situation of China, the ultralow emission modification of atmospheric pollutants is implemented comprehensively, and wet desulphurization has become the mainstream smoke treatment route of most of domestic coal-fired steel plants or power plants. With the wide application of the wet desulphurization process, when the smoke pollutants reach the emission standard, a plurality of problems are caused, one of which is white smoke plume of the smoke. After the flue gas enters the desulfurizing tower, the flue gas is fully contacted with gas and liquid and then reaches saturation, then the flue gas enters a chimney to be discharged to the atmosphere, and the vapor in the flue gas is gradually condensed along with the continuous reduction of the temperature of the flue gas in the discharging process, so that white smoke plume is generated. The lower the air temperature, the larger the condensation amount and the more obvious the white smoke. In recent times, clear standards for white reduction have been proposed in various places, with the most stringent requirements being condensation.

In the existing white smoke elimination mode, one mode is to cool flue gas by forced condensation and circulating water or air, so as to reduce the absolute moisture content of the flue gas and reduce the generation of condensed liquid drops, thereby greatly reducing the white smoke; the other method is to heat the flue gas by 30-40 ℃ by heating treatment by using natural gas flue gas or steam as a heat source, so as to greatly improve the unsaturation degree of the flue gas, thereby completely eliminating visible white smoke, but the process is obvious, needs to consume a large amount of energy, and has very high operation cost;

in order to solve the above problems, CN201611107000 proposes an efficient de-whitening device and an operation method thereof, wherein ambient dry air is used as a cold source, a heat exchanger and a fan are used for forcibly cooling flue gas, on one hand, 15-30% of water vapor in flue gas is condensed through heat exchange phase change to reduce absolute moisture content thereof, and on the other hand, during the heat exchange process, the ambient dry air absorbs latent heat released by flue gas moisture condensation, and the temperature thereof is increased along with the condensation. Finally, the heated dry air is mixed into the smoke and is mixed and discharged to the outside atmosphere, thereby achieving the purpose of eliminating the white smoke. However, this method has the following problems: 1. the excessive air mixing amount increases the occupied area of the chimney: the latent heat of the flue gas is very large, 2-3 times of air is often needed to achieve the dehumidification rate of 15-30%, if the air is mixed into the flue gas, the total flue gas amount is large, the manufacturing cost of a chimney is increased, and the occupied area is increased; 2. residual droplets of flue gas are not effectively demisted: condensing the flue gas. A large amount of condensed water is generated, part of liquid drops are mixed into the flue gas under the disturbance of high-speed airflow to form entrainment, however, the residual liquid drops are not collected by the demister in the process, and the white smoke phenomenon is increased by the part of liquid drops, so that the white smoke eliminating effect is influenced; 3. flue gas and air mix unreasonably: the air and the smoke are mixed because of the impact of two air flows, the resistance of the air flow is increased, and the smoke backflow phenomenon can be caused in severe cases.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: the utility model aims at providing a phase transition mixed flow air-cooling white system that disappears has solved and has mixed the too high chimney that increases of air volume and take up an area of in the white system that disappears at present, and the residual liquid drop of flue gas is not effectively the defogging, and the insufficient problem that leads to the flue gas to flow backward of flue gas and air mixing.

The technical scheme is as follows: the utility model relates to a white system that disappears of phase transition mixed flow formula air-cooling, including plate heat exchanger, plate heat exchanger's hot air stream import and flue gas inflow pipe are linked together, and plate heat exchanger's hot air stream export communicates with each other through the bottom of flue gas outflow pipe with the chimney, plate heat exchanger's cold air stream import and plate heat exchanger's cold air stream export are equallyd divide into high temperature section and low temperature section, and plate heat exchanger's cold air stream import high temperature section is connected with centrifugal fan through first air inflow pipe, and plate heat exchanger's cold air stream export high temperature section communicates with each other through the middle part of air outflow pipe with the chimney, just the inside of chimney lies in the junction fixed mounting of air outflow pipe and chimney and has the deep bead, and the inside of chimney lies in the top.

Furthermore, the low-temperature section of the cold air inlet of the plate heat exchanger is connected with the axial flow fan through a second air inflow pipe. The low temperature section adopts the axial fan of low energy consumption, utilizes cold air to cool down the flue gas, because the flue gas temperature is lower relatively, and the heat transfer difference in temperature is less, consequently can produce a large amount of comdenstions water, direct evacuation.

Furthermore, a wire mesh demister is fixedly arranged inside the flue gas outflow pipe. Utilize the silk screen defroster, the liquid drop that entrains with the flue gas after the condensation is abundant the entrapment, improves dehumidification efficiency, is showing to promote follow-up white effect that disappears.

Furthermore, a sealing plate which is integrally formed with the wind shield is fixedly arranged at the bottom end of the wind shield.

Further, the deep bead is the arc, and the air outlet of deep bead sets up. The wind shield conducts diversion on air, smoke circulates from the side, direct impact of the air and the smoke can be prevented, airflow resistance is prevented from increasing, and the smoke backflow phenomenon is caused.

Has the advantages that: compared with the prior art, the utility model, have following advantage:

(1) the operation cost is low, the centrifugal fan and the axial flow fan are combined, the plate heat exchanger is designed in a grading mode, the centrifugal fan is adopted in the high-temperature section, and cold air is utilized to fully absorb the heat of high-temperature flue gas and mix the heat into the flue gas; the low-temperature section adopts an axial flow fan with low energy consumption, the flue gas is cooled by cold air, and a large amount of condensed water is generated and directly drained because the flue gas temperature is relatively low and the heat exchange temperature difference is small;

(2) compared with other white eliminating devices, the utility model only utilizes the air in the high temperature section, the air mixing quantity is small, the overall process reconstruction range is small, and the investment cost for the reconstruction of the chimney and the related pipelines is relatively reasonable;

(3) air cooling heat exchange is adopted, a circulating water tower and a circulating water tank are not required to be arranged, compared with a water cooling scheme, extra water resources are not consumed, a large amount of condensed water can be condensed in the operation process, and the method can be used in a desulfurization process or other processes and can generate certain benefits;

(4) the air mixing effect is good, and the flue gas and the air are fully mixed by using the wind shield and the mixed flow fan, so that the pressure loss is reduced;

(5) the equipment cost is low, the whitening process target can be completed by adopting a single plate type heat exchanger, and compared with the traditional process (firstly condensing and then heating, and needing two or even three heat exchangers), the method has the advantages of less one-time investment and obvious economic advantages.

Drawings

FIG. 1 is a front view of the present invention;

fig. 2 is a schematic view of a windshield structure.

Detailed Description

The invention will be further described with reference to the following figures and examples:

as shown in fig. 1 and fig. 2, the utility model relates to a phase-change mixed-flow type air-cooling white-removing system, including plate heat exchanger 1, the hot air inlet of plate heat exchanger 1 is linked together with flue gas inflow pipe 2, the hot air outlet of plate heat exchanger 1 is communicated with the bottom of chimney 4 through flue gas outflow pipe 3, the inside fixed mounting of flue gas outflow pipe 3 has wire mesh defroster 5, utilize wire mesh defroster 5, fully catch the liquid drop that the flue gas after the condensation smugglies, improve dehumidification efficiency, show and promote follow-up white-removing effect;

the cold air flow inlet of the plate heat exchanger 1 and the cold air flow outlet of the plate heat exchanger 1 are divided into a high-temperature section and a low-temperature section, the high-temperature section refers to the position of the cold air flow inlet close to the high-temperature hot air flow inlet, and the hot air flow inlet is higher in temperature and is a high-temperature section; the low-temperature section refers to the position of the cold air flow inlet close to the high-temperature hot air flow outlet, and the temperature of the hot air flow outlet is reduced to be the low-temperature section; the high-temperature section of the cold air flow inlet of the plate heat exchanger 1 is connected with a centrifugal fan 7 through a first air flow inlet pipe 6, the centrifugal fan 7 is adopted to absorb cold air in the high-temperature section, after condensation heat exchange, on one hand, high-temperature flue gas is condensed and cooled to generate a large amount of condensed water, on the other hand, the cold air fully absorbs heat of the high-temperature flue gas, and the section has high flue gas temperature, large temperature difference and high heat exchange efficiency, so that the cold air can be heated to a higher temperature for air mixing in the next stage;

the low-temperature section of the cold air inlet of the plate heat exchanger 1 is connected with an axial flow fan 9 through a second air inflow pipe 8; the low-temperature section adopts the axial flow fan 9 with low energy consumption, the flue gas is cooled by cold air, and because the flue gas temperature is relatively low and the heat exchange temperature difference is small, a large amount of condensed water can be generated and directly emptied; after two-stage condensation, compared with the untreated flue gas, the dew point temperature is reduced by about 5-10 ℃, the dehumidification is 15-30%, the absolute moisture content of the flue gas is greatly reduced, and the concentration intensity of the white flue gas is effectively weakened;

the high-temperature section of the cold airflow outlet of the plate heat exchanger 1 is communicated with the middle part of a chimney 4 through an airflow outlet pipe 10, a wind shield 12 is fixedly arranged in the chimney 4 at the joint of the airflow outlet pipe 10 and the chimney 4, the wind shield 12 is arc-shaped, a sealing plate 11 which is integrally formed with the wind shield 12 is fixedly arranged at the bottom end of the wind shield 12, an air outlet of the wind shield 12 is arranged upwards, the wind shield 12 guides air, smoke circulates from the side, direct impact of two airflows of air and smoke can be prevented, airflow resistance is prevented from being increased, and the phenomenon of backflow of the smoke is caused;

a mixed flow fan 13 is also fixedly arranged in the chimney 4 above the wind shield 12, and the mixed flow fan 13 is a SWF series mixed flow fan; hot air generated in a high-temperature section in air cooling heat exchange is only utilized, the hot air is introduced into the chimney 4 through the air outflow pipe 10 to be mixed with the flue gas after temperature reduction and dehydration, the air mixing amount is small, the wind shield 12 and the mixed flow fan 13 are arranged in the chimney 4, the flue gas and the air are fully mixed, the air mixing efficiency is improved, the pressure loss is reduced, the mixed flue gas is changed from a saturated state to an unsaturated state, the moisture content is further reduced, and the flue gas is discharged at a temperature higher than the saturation point by about 10-20 ℃.

The working principle is as follows: high-temperature flue gas after industrial desulfurization enters the plate heat exchanger 1 from a hot air flow inlet of the plate heat exchanger 1 through the flue gas inflow pipe 2, then flows out from a hot air flow outlet of the plate heat exchanger 1, flows into the bottom of the chimney 4 through the flue gas outflow pipe 3 and the wire mesh demister 5, and fully traps liquid drops carried by the condensed flue gas, so that the dehumidification efficiency is improved; compared with the untreated flue gas, the condensed flue gas has the dew point temperature reduced by about 5-10 ℃, the dehumidification is 15-30%, the absolute moisture content of the flue gas is greatly reduced, and the concentration of the white flue gas is effectively weakened;

the centrifugal fan 7 is adopted in the high-temperature section to absorb cold air, after condensation heat exchange, the cold air fully absorbs heat of high-temperature flue gas, the temperature of the flue gas is high, the temperature difference is large, the heat exchange efficiency is high, the cold air can be heated to a higher temperature, then flows into the middle part of the chimney 4 through the air outflow pipe 10, is guided into the mixed flow fan 13 through the wind shield 12, then is mixed with the condensed flue gas through the mixed flow fan 13, the mixed flue gas is changed into an unsaturated state from saturation, the moisture content is further reduced, the temperature is higher than the saturation point by about 10-20 ℃, and the mixed flue gas is discharged, so that visible white smoke is thoroughly eliminated;

the low temperature section adopts the axial fan 9 of low energy consumption, utilizes cold air to cool down the flue gas, because the flue gas temperature is lower relatively, and the heat transfer difference in temperature is less, consequently can produce a large amount of comdenstions water, direct evacuation.

Claims (5)

1. The utility model provides a white system of phase transition mixed flow forced air cooling disappears, includes plate heat exchanger, its characterized in that: the hot air inlet of the plate heat exchanger is communicated with the flue gas inflow pipe, the hot air outlet of the plate heat exchanger is communicated with the bottom of the chimney through the flue gas outflow pipe, the cold air inlet of the plate heat exchanger and the cold air outlet of the plate heat exchanger are equally divided into a high-temperature section and a low-temperature section, the cold air inlet high-temperature section of the plate heat exchanger is connected with the centrifugal fan through the first air inflow pipe, the cold air outlet high-temperature section of the plate heat exchanger is communicated with the middle of the chimney through the air outflow pipe, a wind shield is fixedly installed at the joint of the air outflow pipe and the chimney inside the chimney, and a mixed flow fan is fixedly installed above the wind shield inside the chimney.

2. The phase-change mixed-flow air-cooled whitening system according to claim 1, wherein: and the low-temperature section of the cold air inlet of the plate heat exchanger is connected with the axial flow fan through a second air inflow pipe.

3. The phase-change mixed-flow air-cooled whitening system according to claim 1, wherein: and a wire mesh demister is fixedly arranged inside the smoke outflow pipe.

4. The phase-change mixed-flow air-cooled whitening system according to claim 1, wherein: and a sealing plate which is integrally formed with the wind shield is fixedly arranged at the bottom end of the wind shield.

5. The phase-change mixed-flow air-cooled whitening system according to claim 4, wherein: the deep bead is the arc, and the air outlet of deep bead sets up.

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