CN107875835A - A kind of flue gas of slurries cooling mixes wind and disappeared white system - Google Patents

Abstract

A slurry-cooled flue gas mixed-air dewhitening system, involving a wet desulfurization flue gas dewhitening process system, including a desulfurization tower, a slurry spray pipeline, a slurry cooler, an air pipeline, a chimney, and a slurry spray pipe The slurry heat exchanger on the road cools the slurry. The cooled slurry is distributed through the spray pipe and reacts with the flue gas to realize the process of desulfurization, cooling and dehumidification. The desulfurized flue gas is mixed with hot air and enters the chimney. The chimney is discharged into the atmosphere, and there is no white plume when the flue gas is discharged. The invention has simple process route, less equipment investment, convenient modification and simple implementation.

Description

A slurry-cooled flue gas mixing air elimination system

technical field

The invention relates to the application field of flue gas desulfurization, in particular to a slurry-cooled flue gas mixing air whitening system.

Background technique

Existing flue gas and tail gas in industries such as electric power, iron and steel, and biochemical industry generally go through desulfurization, destocking and other processing equipment. Especially after the ultra-low emission transformation of the power industry, the control indicators are determined to be 4 indicators of soot, sulfur dioxide, nitrogen oxides, mercury and their compounds, and the emission limits are 10mg/m ³ , 35mg/m ³ , 50mg/m ³ , 0.03mg/m ³ , and some areas require a smoke emission limit of 5mg/m ³ . From an environmental point of view, the elimination of pollutants has been greatly improved.

Most of the existing flue gas and tail gas pass through wet desulfurization or spray towers, and limestone-gypsum wet technology is generally used for flue gas desulfurization treatment. However, the water vapor in the flue gas desulfurized by limestone-gypsum and other wet technologies is basically in a saturated state, and the moisture content is high. , forming white mist around the chimney, commonly known as "smoke plume". The exhausted flue gas or exhaust gas has low temperature and high moisture content, which cannot be effectively diffused and promotes the formation of smog, causing troubles to citizens' life and vision.

These enterprises generally have the phenomenon of "white smoke" in the production process. The reason for this phenomenon is: the saturated flue gas is rapidly cooled by the lower temperature atmosphere, the water vapor in the flue gas condenses into a liquid state, and the condensed water droplets produce light The light transmittance of the refracted and scattered smoke decreases, so that the smoke plume appears white and forms a white smoke plume. However, as the smoke diffuses and is diluted by the atmosphere, the white smoke gradually decreases until it disappears.

In order to eliminate white smoke, the existing technology is mainly to install a flue gas heating heat exchanger between the desulfurization tower and the chimney, and solve the problem of "smoke plume" caused by the condensation of water vapor in the flue gas by increasing the temperature of the flue gas, but the effect is not good. Great, mostly because:

(1) The water vapor in the flue gas is saturated, the moisture content is large, and the heat load of the flue gas is huge;

(2) Most of the existing flue gas heating heat exchangers are finned tube heat exchangers, which have low heat transfer efficiency and large footprint, which cannot meet the requirements of existing site renovation;

(3) The flue gas after desulfurization contains a certain amount of gypsum particles, which is easy to block the heat exchanger;

In addition, if only adding a flue gas condenser or a flue gas heater between the desulfurization tower and the chimney to dehumidify and raise the temperature, the flue gas heat exchanger will easily cause corrosion failure due to the corrosive medium in the flue gas.

Contents of the invention

The core of eliminating the white "plume" is to reduce the water vapor emission in the flue gas and increase the superheat of the water vapor in the flue gas. Based on this, the present invention starts from the following aspects:

1) The moisture content in the flue gas is related to the flue gas temperature, the lower the flue gas temperature, the smaller the moisture content;

2) In the case of the same moisture content, the higher the flue gas temperature, the greater the superheat of the water vapor in the flue gas, and the less or even disappear the white plume.

In summary, the present invention has the following innovations:

1) Use the slurry cooler to directly cool the slurry, and the cooled slurry will react with the flue gas to reduce the temperature and humidity of the flue gas while improving the desulfurization efficiency;

2) On the basis of reducing the moisture content of the flue gas, using hot air to mix with the flue gas, the temperature of the mixed flue gas increases and the superheat of the water vapor increases, which solves the problem of blockage and corrosion of the flue gas heater, and solves the problem of white Plume problem.

The present invention is achieved through the following technical solutions:

A slurry-cooled flue gas mixing and whitening system, comprising a desulfurization tower, a smoke exhaust pipeline connected to the flue gas outlet of the desulfurization tower, an air pipeline connected to the end of the smoke exhaust pipeline, and respectively connected to the smoke exhaust pipeline, The confluence pipeline connected with the air pipeline and the chimney connected with the confluence pipeline, wherein,

The desulfurization tower includes a desulfurization tower body, a slurry storage tank located at the bottom of the desulfurization tower body, a slurry spray pipeline connected to the slurry storage tank, and a slurry cooler located on the slurry spray pipeline. The inlet of the shower line is set at the bottom of the slurry storage tank, and the outlet of the slurry spray line is set at the top of the desulfurization tower. to cool down;

There is hot air in the air pipeline, the outlet of the air pipeline and the outlet of the smoke exhaust pipeline are connected to the inlet of the confluence pipeline, and the outlet of the confluence pipeline is connected to the smoke inlet provided at the bottom of the chimney;

The flue gas enters the desulfurization tower through the flue gas inlet of the desulfurization tower, sprays through the slurry spray pipe, enters the exhaust pipe, and enters the confluence pipe together with the hot air in the air pipe, and finally discharges through the chimney.

The slurry cooler is a plate heat exchanger, the heat transfer element is composed of corrugated plates, and a plurality of corrugated plates are stacked to form a plate bundle to form a slurry flow channel and a cooling medium flow channel, wherein the two sides of the slurry flow channel The sum of the heights of the corrugated protrusions is less than the height of the slurry channel.

The flue gas outlet of the desulfurization tower is provided with a flue gas condenser.

The flue gas condenser is a plate heat exchanger, the heat transfer element is composed of corrugated plates, and a plurality of corrugated plates are stacked to form a plate bundle and form a flue gas flow channel and a cooling medium flow channel, wherein the flue gas flow The sum of the heights of the corrugated protrusions on both sides of the channel is less than the height of the flue gas channel; the inlet of the heat medium channel of the flue gas condenser is connected with the flue gas outlet of the desulfurization tower, and the outlet of the heat medium channel is connected with the inlet of the air pipeline; The cold medium channel of the gas condenser passes through the cooling medium.

The cooling medium passing through the cold medium passage of the flue gas condenser is air, and the outlet of the cold medium passage of the flue gas condenser communicates with the inlet of the air pipeline. , The air pipeline is provided with an air heater.

The beneficial effects of the present invention are:

In the present invention, a plate heat exchanger is arranged at the outlet of the desulfurization tower, and the flue gas is condensed and cooled by the plate heat exchanger to achieve the purpose of dehumidification, and then the hot air is mixed with the dehumidified flue gas to increase the superheat of the water vapor in the flue gas , to achieve the purpose of whitening, and the beneficial effects achieved mainly include:

1) Use the slurry heat exchanger to cool the slurry, and then use the cooled slurry to desulfurize the flue gas, improve the desulfurization efficiency and reduce the moisture content in the flue gas.

2) The flue gas condenser with a straight channel structure can not only obtain higher heat transfer efficiency, reduce the heat transfer area of the heat exchanger, but also reduce the size and footprint of the heat exchanger, and at the same time solve the unavoidable problems of traditional heat exchangers. Smoke blockage problem. The flue gas side straight channel flow channel design, that is, the flue gas side channel height is greater than the corrugation height, forming a non-contact flue gas straight channel structure, the flue gas goes straight through, and prevents the accumulation and blockage of gypsum particles in the flue gas. Conventional plate heat exchanger clogging problem.

3) The hot air and the dehumidified flue gas are directly mixed outside the chimney, which optimizes the system flow, reduces the flue gas heating heat exchanger, and solves the problem of wet flue gas corrosion on the chimney. The process route is simple and the cost is low.

Description of drawings

Fig. 1 is a schematic diagram of the connection structure of the present invention.

2-4 are schematic diagrams of other three connection structures of the present invention.

Fig. 5 is a schematic cross-sectional view of the flow channel of the slurry cooler of the present invention.

Fig. 6 is a schematic cross-sectional view of the flow path of the flue gas condenser of the present invention.

In the figure: 1. Desulfurization tower, 2. Slurry spray pipeline, 3. Air pipeline, 4. Slurry cooler, 401. Slurry cooler corrugated plate, 5. Chimney, 6. Air heater, 7. Smoke Gas condenser, 701. Corrugated plate of flue gas condenser, 8. Smoke exhaust pipeline, 9. Slurry storage tank, 10. Confluence pipeline, 11. Desulfurization tower body.

A. Raw smoke, B. Clean smoke, C. Hot air, D. Cooling medium, E. Slurry, F. Cooling medium, G. Heating medium, H. Condensate, H1. Slurry flow channel height, H2. Slurry flow The height of the corrugation on one side of the road,

H3. The height of the corrugated protrusions on the other side of the slurry flow channel, h1. The height of the flue gas flow channel, h2. The height of the corrugated protrusions on one side of the flue gas flow channel, h3. The height of the corrugated protrusions on the other side of the flue gas flow channel.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments.

As shown in Figure 1, the present invention comprises a desulfurization tower 1, a smoke exhaust pipeline 8 communicated with the flue gas outlet of the desulfurization tower, an air pipeline 3 connected to the end of the smoke exhaust pipeline, connected with the smoke exhaust pipeline, the air pipe respectively The confluence pipeline 10 communicated with the road and the chimney 5 communicated with the confluence pipeline, wherein,

The desulfurization tower includes a desulfurization tower body 11, a slurry storage tank 9 located at the bottom of the desulfurization tower body, a slurry spray pipeline 2 connected to the slurry storage tank, and a slurry cooler 4 located on the slurry spray pipeline, The inlet of the slurry spray pipeline is set at the bottom of the slurry storage tank, and the outlet of the slurry spray pipeline is set at the top of the desulfurization tower body. The cold medium flow channel of the slurry cooler passes through the cold medium D, and the heat The slurry E in the medium channel is cooled;

There is hot air C in the air pipeline, the outlet of the air pipeline and the outlet of the smoke exhaust pipeline are connected to the inlet of the confluence pipeline, and the outlet of the confluence pipeline is connected to the smoke inlet provided at the bottom of the chimney;

The flue gas enters the desulfurization tower through the flue gas inlet of the desulfurization tower, sprays through the slurry spray pipe, enters the exhaust pipe, and enters the confluence pipe together with the hot air in the air pipe, and finally discharges through the chimney.

Preferably, the flue gas outlet of the desulfurization tower is provided with a flue gas condenser, the flue gas condenser is a plate heat exchanger, the heat transfer element is composed of corrugated plates, and multiple corrugated plates are stacked to form a plate bundle and form a flue gas The flow channel and the cooling medium flow channel, wherein the sum of the heights of the corrugated protrusions on both sides of the flue gas flow channel is less than the height of the flue gas channel; the inlet of the heat medium channel of the flue gas condenser communicates with the flue gas outlet of the desulfurization tower , the outlet of the hot medium channel communicates with the inlet of the air pipeline; the cold medium channel of the flue gas condenser passes through the cooling medium.

Further preferably, the cooling medium passing through the cold medium passage of the flue gas condenser is air, and the outlet of the cold medium passage of the flue gas condenser communicates with the inlet of the air pipeline.

The raw smoke A enters the tower body through the flue gas inlet, and the passing slurry spray pipeline reacts with the slurry E to become clean smoke B, which is output through the smoke exhaust pipeline and mixed with the hot air in the air pipeline. The temperature of the mixed flue gas is increased, the relative humidity is reduced, and the white plume is eliminated during the discharge through the chimney. Compared with the existing technology, air is used to cool down the flue gas after desulfurization, and the air temperature is increased. After the heated air is mixed with the cooled flue gas outside the chimney, the temperature of the flue gas is increased on the one hand, and the temperature of the flue gas is increased on the other hand. The superheat of the water vapor in the flue gas avoids the corrosion of the chimney caused by the wet flue gas directly entering the chimney (wet chimney). The flue gas passes through the flue gas condenser to achieve dehumidification, and mixes with air to achieve temperature rise and increase the superheat, thereby eliminating the white smoke plume .

As shown in Figure 2, combined with Figure 1, the air is heated by the air heater 6 and mixed with the flue gas after desulfurization treatment, and the flue gas enters the chimney after the temperature rises and the degree of superheat increases, eliminating the white smoke plume during the flue gas discharge process. The air heater can be a heat exchanger, which raises the temperature of the flue gas through the heating medium G.

As shown in Figure 3, combined with Figure 1, the flue gas treated by the desulfurization tower enters the flue gas condenser 7, and exchanges heat with the air from the air pipeline. Outside the system, the flue gas temperature and moisture content decrease, and the cooled flue gas is mixed with air again, and the mixed flue gas enters the chimney and is discharged into the atmosphere through the chimney outlet. As the flue gas temperature increases and the humidity content decreases, eliminating White smoke plume during flue gas emission.

As shown in Figure 3, combined with Figure 2, the flue gas treated by the desulfurization tower enters the flue gas condenser, and under the action of the cooling medium, the water vapor in the flue gas is condensed and precipitated to become condensate H and discharged to the outside of the system , the flue gas temperature and moisture content decrease, the flue gas after cooling and dehumidification is mixed with the air heated by the air heater, and the mixed flue gas enters the chimney and is discharged into the atmosphere through the chimney outlet. The amount is reduced and the white plume in the smoke emission process is eliminated.

As shown in Figure 5, the slurry cooler consists of multiple corrugated plates 401 of the slurry cooler stacked to form a slurry flow channel and a cold medium flow channel. The sum of the heights H2 and H3 of the corrugations on both sides of the slurry flow channel is less than the slurry flow Channel height H1, that is, H1>H2+H3, correspondingly, the corrugations in the slurry flow channel cannot form contacts, that is, the slurry flows in the non-contact channel, which solves the stagnation point problem of the flow field of tubular and conventional plate heat exchangers , the gypsum particles in the slurry are not easy to accumulate, thus solving the clogging problem. At the same time, because the heat transfer element is a corrugated plate, compared with the tubular flue gas heat exchanger, the heat transfer efficiency is high, the temperature difference at the cold end is small, and the same cold source conditions , the slurry outlet temperature is lower.

As shown in Figure 6, the flue gas condenser is stacked by a plurality of flue gas condenser corrugated plates 701 to form a flue gas flow channel and a cold medium flow channel. and less than the height h1 of the flue gas flow channel, that is, h1>h2+h3, correspondingly, the corrugations in the flue gas flow channel cannot form contacts, that is, the flue gas flows in the non-contact channel, which solves the problem of heat exchange between tube type and conventional plate type The problem of the stagnation point of the flow field of the device, the gypsum particles in the flue gas are not easy to accumulate, thereby solving the problem of blockage, and because the heat transfer element is a corrugated plate, compared with the tubular flue gas heat exchanger, the heat transfer efficiency is high, and the cold The end temperature difference is small, and under the same cold source conditions, the outlet temperature of the flue gas is lower, and the corresponding moisture content is lower, thereby achieving the purpose of cooling and dehumidification. Further, as the cooling medium F for cooling the flue gas, it can be air, cooling water or other refrigerants.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (6)

1. A flue gas mixing air whitening system for slurry cooling, characterized in that it comprises a desulfurization tower, a smoke exhaust pipeline connected with the flue gas outlet of the desulfurization tower, and an air pipeline connected to the end of the smoke exhaust pipeline, respectively The confluence pipeline connected with the smoke exhaust pipeline and the air pipeline and the chimney connected with the confluence pipeline, wherein, The desulfurization tower includes a desulfurization tower body, a slurry storage tank located at the bottom of the desulfurization tower body, a slurry spray pipeline connected to the slurry storage tank, and a slurry cooler located on the slurry spray pipeline. The inlet of the shower line is set at the bottom of the slurry storage tank, and the outlet of the slurry spray line is set at the top of the desulfurization tower. to cool down; There is hot air in the air pipeline, the outlet of the air pipeline and the outlet of the smoke exhaust pipeline are connected to the inlet of the confluence pipeline, and the outlet of the confluence pipeline is connected to the smoke inlet provided at the bottom of the chimney; The flue gas enters the desulfurization tower through the flue gas inlet of the desulfurization tower, sprays through the slurry spray pipe, enters the exhaust pipe, and enters the confluence pipe together with the hot air in the air pipe, and finally discharges through the chimney. 2. A slurry-cooled flue gas mixing and whitening system according to claim 1, characterized in that the slurry cooler is a plate heat exchanger, the heat transfer element is composed of corrugated plates, and a plurality of corrugated plates The sheets are stacked to form a plate bundle to form a slurry flow channel and a cooling medium flow channel, wherein the sum of the heights of the corrugated protrusions on both sides of the slurry flow channel is smaller than the height of the slurry channel. 3. A slurry-cooled flue gas mixed air whitening system according to claim 1 or 2, characterized in that a flue gas condenser is provided at the flue gas outlet of the desulfurization tower. 4. A slurry-cooled flue gas mixing and whitening system according to claim 3, wherein the flue gas condenser is a plate heat exchanger, and the heat transfer element is composed of corrugated plates, and a plurality of corrugated plates The plates are stacked to form a plate bundle and form a flue gas flow path and a cooling medium flow path, wherein the sum of the heights of the corrugated protrusions on both sides of the flue gas flow path is less than the height of the flue gas channel; the heat of the flue gas condenser The inlet of the medium channel is connected with the flue gas outlet of the desulfurization tower, the outlet of the hot medium channel is connected with the inlet of the air pipeline; the cold medium channel of the flue gas condenser passes through the cooling medium. 5. A kind of flue gas mixing air whitening system of slurry cooling according to claim 4, it is characterized in that, the cooling medium that passes in the cold medium channel of described flue gas condenser is air, and the cooling medium of flue gas condenser The outlet of the medium flow channel communicates with the inlet of the air pipeline. 6 . A slurry-cooled flue gas mixed air whitening system according to claim 4 or 5 , characterized in that an air heater is provided on the air pipeline. 7 .