Light ash calcination furnace gas washing and condensing system

Abstract

The utility model discloses a light ash calcining furnace gas washing and condensing system which comprises a washing and condensing tower, the upper part of the washing and condensing tower is a washing section, and the lower part of the washing and condensing tower is a condensing section; the washing section is a corrugated pipe heat exchanger, the furnace gas passes through the corrugated pipe heat exchanger from top to bottom, and the mother liquor passes through the corrugated pipe heat exchanger from bottom to top, so that the furnace gas and the mother liquor reversely flow in the corrugated pipe heat exchanger for indirect heat exchange; a condensate recovery device is further arranged at the bottom of the corrugated pipe heat exchanger. The top of the corrugated pipe heat exchanger is connected with a furnace gas leading-in pipe, and the bottom is connected with a furnace gas leading-out pipe; furnace gas enters the corrugated pipe heat exchanger from the furnace gas introduction pipe and passes through the corrugated pipe heat exchanger along the tube pass. The bottom of the corrugated pipe heat exchanger is connected with a mother liquor lead-in pipe, and the top is connected with a mother liquor lead-out pipe; mother liquor enters the corrugated pipe heat exchanger from the mother liquor introducing pipe and passes through the corrugated pipe heat exchanger along a shell pass. According to the washing condensing tower, the existing washing condensing tower is improved, so that the consumption of crude salt is reduced, and water is saved.

Description

Technical Field

[0001] The utility model relates to the field of furnace gas washing, in particular to a calcined light ash furnace gas washing condensation system. Background Art

[0002] At present, the washing section of the light ash gas washing and condensing tower in the calcining workshop is filled with polypropylene ball rings. The mother liquid enters from the top of the tower and the gas enters from the bottom of the tower. The gas and the mother liquid are in direct contact for heat exchange, so there will be a small tower loss, high raw salt consumption, and most of the gas condensate will enter the hot mother liquid. The gas condensate is not effectively recovered, resulting in a large waste. In view of the above problems, the existing washing and condensing tower is improved. Summary of the invention

[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the utility model provides a calcined light ash furnace gas washing and condensing system, which improves the existing washing and condensing tower, aiming to reduce the consumption of raw salt and save water.

[0004] Technical solution: To achieve the above-mentioned purpose, the utility model provides a calcined light ash furnace gas washing and condensing system, comprising a washing and condensing tower, the upper part of which is a washing section, and the lower part of which is a condensing section; the washing section is a bellows heat exchanger, the furnace gas passes through the bellows heat exchanger from top to bottom, and the mother liquid passes through the bellows heat exchanger from bottom to top, so that the furnace gas and the mother liquid are indirectly heat exchanged in a countercurrent manner in the bellows heat exchanger; a condensate recovery device is also provided at the bottom of the bellows heat exchanger.

[0005] Furthermore, the top of the bellows heat exchanger is connected to a furnace gas inlet pipe, and the bottom is connected to a furnace gas outlet pipe; the furnace gas enters the bellows heat exchanger from the furnace gas inlet pipe, passes through the bellows heat exchanger along the tube path, and then enters the condensation section through the furnace gas outlet pipe.

[0006] Furthermore, a soft water spray device is provided on the top of the bellows heat exchanger.

[0007] Furthermore, the soft water spray device includes a spray water supply pipe and a spray head. The spray water supply pipe is connected to the furnace gas inlet pipe. The spray head is arranged at one end of the furnace gas inlet pipe extending into the corrugated tube heat exchanger. The spray water supply pipe can supply water to the spray head through the furnace gas inlet pipe.

[0008] Furthermore, the bottom of the bellows heat exchanger is connected to a mother liquid inlet pipe, and the top is connected to a mother liquid outlet pipe; the mother liquid enters the bellows heat exchanger from the mother liquid inlet pipe, passes through the bellows heat exchanger along the shell side, and then enters the cyclone separator through the mother liquid outlet pipe.

[0009] Furthermore, the cyclone separator is provided with a liquid separation tube and a gas separation tube; the mother liquor is separated into gas and liquid in the cyclone separator, the separated gas enters the condensation section along the gas separation tube, and the separated liquid enters the hot mother liquor barrel along the liquid separation tube.

[0010] Furthermore, the condensate recovery device includes a condensate storage tank, and drainage pipes are respectively provided at the bottom of the bellows heat exchanger and the condensation section, and the output end of the drainage pipe is led to the condensate storage tank, so that the condensate generated in the bellows heat exchanger and the condensation section can flow into the condensate storage tank.

[0011] Furthermore, the condensate storage tank is connected to an external delivery pipeline, and a condensate pump is arranged on the external delivery pipeline. The condensate pump can pump the condensate in the condensate storage tank into the dilute liquid barrel through the external delivery pipeline.

[0012] Furthermore, the condensation section is a water box type condensation tower.

[0013] Beneficial effects: The utility model is a calcined light ash furnace gas washing and condensing system, and its beneficial effects are as follows:

[0014] 1) The washing section at the top of the washing condensation tower is changed from a packed tower to a bellows heat exchanger, so that the furnace gas and the mother liquid can exchange heat indirectly, without generating small tower losses and reducing the consumption of raw salt;

[0015] 2) The furnace gas is separated from the mother liquor, and the condensate will not enter the mother liquor. In addition, a condensate recovery device is provided to effectively recover the condensate. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Attached Figure 1 It is a schematic diagram of the calcined light ash furnace gas washing and condensation system of the utility model. DETAILED DESCRIPTION

[0017] The utility model is further described below in conjunction with the accompanying drawings.

[0018] As attached Figure 1 The calcined light ash furnace gas washing and condensing system comprises a washing and condensing tower 1, the upper part of the washing and condensing tower 1 is a washing section, and the lower part of the washing and condensing tower 1 is a condensing section. The condensing section is a water box type condensing tower 16. In the prior art, the washing section is a packing tower, while in the utility model, the washing section is a bellows heat exchanger 2. The furnace gas passes through the bellows heat exchanger 2 from top to bottom, and the mother liquid passes through the bellows heat exchanger 2 from bottom to top, so that the furnace gas and the mother liquid are countercurrently indirectly exchanged with heat in the bellows heat exchanger 2, so that no small tower loss is generated. According to the current small tower loss of 1.4%, the annual output is 1.4 million tons, and the raw salt consumption can be saved by 41,160 tons each year. According to the raw salt purchase price of 94 yuan / ton, 3.87 million yuan can be saved.

[0019] Since the furnace gas and the mother liquor exchange heat indirectly, the condensate will not enter the mother liquor, and a condensate recovery device is also provided at the bottom of the bellows heat exchanger 2. Therefore, compared with the direct heat exchange of the original packed tower, the furnace gas condensate in the bellows heat exchanger 2 is effectively recovered.

[0020] The H2O content in the furnace gas produced by the calcining furnace is about 29kmol / t, and the H2O content in the exhaust gas after condensation is about 12.3kmol / t. According to the calculation based on the saturated partial pressure of water vapor under the operating conditions, the condensed water vapor content is about 16.7kmol / t, which is about 0.3m 3 / t alkali, based on an annual output of 1.4 million tons, the amount of condensate produced each year is approximately 420,000 m 3 The waste dilute liquid after distillation in the dilute liquid distillation tower will be used for salt and ash treatment, saving about 420,000 m3 of water per year. 3 .

[0021] In addition, the condensate is separated from the mother liquor by indirect heat exchange, which can reduce the mother liquor equivalent by about 0.3m 3 / t alkali, thus reducing the load of the ammonia evaporation tower. Compared with the original packed tower direct heat exchange, there is no need to add an ammonia evaporation tower. In addition, the reduction of mother liquor is conducive to reducing the steam consumption and ammonia consumption of ammonia evaporation, and at the same time, the discharge of calcium liquid for ammonia evaporation can be reduced by about 420,000m3 per year. 3 .

[0022] Compared with the original packed tower direct heat exchange, the pressure difference of the furnace gas system resistance of the bellows heat exchanger 2 will be further reduced, and the heat loss of the furnace gas will be reduced, which is conducive to saving the amount of light ash steam. With the reduction of the pressure of the furnace gas system, the working environment of the light ash section can be effectively improved, and the compressor pumping efficiency can be improved. In addition, the utility model can also increase the temperature of the hot mother liquid, save ammonia steam, reduce the amount of ammonia steam, and save about 2,175 tons of standard coal per year.

[0023] As attached Figure 1 As shown in the figure, the top of the bellows heat exchanger 2 is connected with a furnace gas inlet pipe 3 and a mother liquid inlet pipe 7, and the bottom is connected with a furnace gas outlet pipe 4 and a mother liquid outlet pipe 8. The furnace gas from the hot alkali liquid tower enters the top of the bellows heat exchanger 2 from the furnace gas inlet pipe 3, passes through the bellows heat exchanger 2 along the tube side, and the cold mother liquid from the filtration process enters the bellows heat exchanger 2 from the mother liquid inlet pipe 7, passes through the bellows heat exchanger 2 along the shell side, and the furnace gas and the cold mother liquid exchange heat indirectly in the bellows heat exchanger 2 in a countercurrent manner.

[0024] After heat exchange, the furnace gas is led out from the bottom of the corrugated tube heat exchanger through the furnace gas outlet pipe 4, and then enters the water box condensing tower 16. After heat exchange, the mother liquor will be heated to about 70°C, and the hot mother liquor will enter the cyclone separator 9 through the mother liquor outlet pipe 8. The cyclone separator 9 is provided with a liquid separation pipe 10 and a gas separation pipe 11. The hot mother liquor is separated into gas and liquid in the cyclone separator 9, and ammonia and carbon dioxide in the hot mother liquor are evaporated. The gas separated from the mother liquor enters the water box condensing tower 16 along the gas separation pipe 11. The gas separation pipe 11 is connected to the furnace gas outlet pipe 4, so the furnace gas and the gas separated from the mother liquor will enter the water box condensing tower 16 together. The liquid separated from the mother liquor is generally around 6270°C, and it will flow along the liquid separation pipe 10 and enter the hot mother liquor barrel of the ammonia evaporation and absorption process.

[0025] The furnace gas flows through the shell side in the water-box condensation tower 16, and the circulating cooling water flows through the tube side in the water-box condensation tower 16. After the furnace gas is cooled to 40°C by the circulating water, it comes out from the lower part of the water-box condensation tower 16 and is collected in the furnace gas main pipe. Then, the furnace gas is sent to the furnace gas washing tower from the furnace gas main pipe, where it is directly sprayed and washed by the clean ammonia water from the steam absorption station, the softened water from the water gas workshop, and the return water from the lower section of the compression station, further reducing the furnace gas temperature, recovering the ammonia in the furnace gas, and the clean ammonia water and the ammonia in the furnace gas are dissolved to produce washing liquid. Through the washing liquid pump, part of it enters the hot alkali liquid and condensate for water replenishment, and part of it is sent to the filtration process and the alkali car for washing water. The furnace gas is then drawn out from the upper part of the furnace gas washing tower and enters the compression process.

[0026] The condensate recovery device includes a condensate storage tank 12, and a drainage pipe 13 is provided on the bottom of the bellows heat exchanger 2 and the water box condensation tower 16. The output end of the drainage pipe 13 is led to the condensate storage tank 12, so that the condensate generated in the bellows heat exchanger 2 and the water box condensation tower 16 can flow into the condensate storage tank 12. The condensate storage tank 12 is connected to an external delivery pipeline 14, and a condensate pump 15 is provided on the external delivery pipeline 14. The condensate pump 15 can deliver the condensate in the condensate storage tank 12 to the dilute liquid barrel of the evaporation and absorption process through the external delivery pipeline 14.

[0027] A soft water spray device is provided on the top of the bellows heat exchanger 2. The soft water spray device includes a spray water supply pipe 5 and a spray head 6. The spray water supply pipe 5 is connected to the furnace gas inlet pipe 3. The spray head 6 is provided at one end of the furnace gas inlet pipe 3 extending into the bellows heat exchanger 2. The spray water supply pipe 5 can supply water to the spray head 6 through the furnace gas inlet pipe 3. The added soft water spray device uses softened water as a medium to clean the bellows regularly to prevent pipe blockage. In addition, when alkali powder suddenly enters the bellows heat exchanger 2, soft water can also be added for cleaning to prevent the bellows from being blocked.

[0028] An embodiment of the utility model is as follows: Since the establishment of the factory in 2004, the light ash section of the calcining workshop has installed a total of 5 washing and condensing towers 1, with the specifications of the washing section being φ2600×13130, the specifications of the condensing section being φ2800×17990, the specifications of the polypropylene ball ring packing being φ76×76×2.8, and the packing layer height being 4800mm; nine cooling boxes, the specifications of the stainless steel cooling pipe being φ63×3, the total cooling area being 1717㎡, and the design capacity being 900,000 tons / year. After a light ash calcining furnace was added in 2012, the furnace gas system was not optimized, resulting in a large pressure difference in the furnace gas system and a poor on-site working environment. In order to further optimize the furnace gas system, a furnace gas washing and condensing tower 1 was added in 2023, and the washing section was a bellows heat exchanger 2. The project installation and commissioning were completed on October 10, and the material production was carried out on October 11. Through the implementation of the new furnace gas washing and condensing tower project, the negative pressure of the calcined light ash furnace gas system was reduced, and the hot mother liquor equivalent decreased by 0.19m 3 / t alkali, and the water-saving effect is obvious.

[0029] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A calcined light ash furnace gas washing and condensation system, characterized in that: The invention comprises a washing and condensing tower (1), wherein the upper part of the washing and condensing tower (1) is a washing section and the lower part is a condensing section; the washing section is a bellows heat exchanger (2), the furnace gas passes through the bellows heat exchanger (2) from top to bottom, and the mother liquid passes through the bellows heat exchanger (2) from bottom to top, so that the furnace gas and the mother liquid are subjected to countercurrent indirect heat exchange in the bellows heat exchanger (2); a condensate recovery device is also provided at the bottom of the bellows heat exchanger (2).

2. A calcined light ash furnace gas washing and condensation system according to claim 1, characterized in that: The top of the bellows heat exchanger (2) is connected to a furnace gas inlet pipe (3), and the bottom is connected to a furnace gas outlet pipe (4); the furnace gas enters the bellows heat exchanger (2) from the furnace gas inlet pipe (3), passes through the bellows heat exchanger (2) along the tube path, and then enters the condensation section through the furnace gas outlet pipe (4).

3. A calcined light ash furnace gas washing and condensation system according to claim 2, characterized in that: A soft water spray device is provided on the top of the bellows heat exchanger (2).

4. A calcined light ash furnace gas washing and condensation system according to claim 3, characterized in that: The soft water spray device comprises a spray water supply pipe (5) and a spray head (6); the spray water supply pipe (5) is connected to the furnace gas introduction pipe (3); the spray head (6) is arranged at one end of the furnace gas introduction pipe (3) extending into the corrugated tube heat exchanger (2); the spray water supply pipe (5) can supply water to the spray head (6) through the furnace gas introduction pipe (3).

5. The calcined light ash furnace gas washing and condensation system according to claim 1, characterized in that: The bottom of the bellows heat exchanger (2) is connected to a mother liquid introduction pipe (7), and the top is connected to a mother liquid outlet pipe (8); the mother liquid enters the bellows heat exchanger (2) from the mother liquid introduction pipe (7), passes through the bellows heat exchanger (2) along the shell side, and then enters the cyclone separator (9) through the mother liquid outlet pipe (8).

6. A calcined light ash furnace gas washing and condensation system according to claim 5, characterized in that: The cyclone separator (9) is provided with a liquid separation tube (10) and a gas separation tube (11); the mother liquid is separated into gas and liquid in the cyclone separator (9), the separated gas enters the condensation section along the gas separation tube (11), and the separated liquid enters the hot mother liquid barrel along the liquid separation tube (10).

7. The calcined light ash furnace gas washing and condensation system according to claim 1, characterized in that: The condensate recovery device comprises a condensate storage tank (12), and a drainage pipe (13) is respectively arranged at the bottom of the bellows heat exchanger (2) and on the condensation section, and the output end of the drainage pipe (13) is led to the condensate storage tank (12), so that the condensate generated in the bellows heat exchanger (2) and the condensation section can flow into the condensate storage tank (12).

8. A calcined light ash furnace gas washing and condensation system according to claim 7, characterized in that: The condensate storage tank (12) is connected to an external delivery pipeline (14), and a condensate pump (15) is disposed on the external delivery pipeline (14). The condensate pump (15) can deliver the condensate in the condensate storage tank (12) to a dilute liquid tank through the external delivery pipeline (14).

9. A calcined light ash furnace gas scrubbing and condensing system according to any one of claims 1 to 8, characterized in that: The condensation section is a water box type condensation tower (16).

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