Deslagging tail gas treatment device for furfural device

Abstract

The utility model discloses a furfural device deslagging tail gas treatment device which comprises a steam-slag separator, an absorption tower, a flash tower and a filter press, the feeding end of the steam-slag separator is connected with the deslagging end of a hydrolysis kettle, and the gas discharging end of the steam-slag separator is connected with the gas inlet end of the absorption tower through a steam washer; an exhaust end of the absorption tower is connected with an input end of a first gas-liquid separation tank through a first condenser, a bottom storage tank is arranged at the bottom of the absorption tower, and a first liquid outlet end of the bottom storage tank of the absorption tower is connected with a top liquid inlet end of the absorption tower through a circulating main pump; a second liquid outlet end of the absorption tower bottom storage tank is connected with an upper end liquid inlet end of the absorption tower through a flash tower, a circulating auxiliary pump and a cooler; and a third liquid outlet end of the absorption tower is connected with an input end of the filter press through a filter pressing pump. According to the utility model, equipment such as the steam-slag separator, the absorption tower, the flash tower and the filter press is adopted, so that huge construction investment of environment-friendly equipment and facilities is saved, and high operation and maintenance costs are saved.

Description

Technical Field

[0001] This utility model belongs to the field of biomass utilization technology, specifically relating to a furfural plant slag and tail gas treatment device. Background Technology

[0002] Furfural is an organic compound with the chemical formula C5H4O2. It is a colorless, transparent, oily liquid with a distinctive odor similar to benzaldehyde. It is mainly used as an industrial solvent and can also be used to produce furfuryl alcohol, furoic acid, tetrahydrofuran, γ-valerolactone, pyrrole, tetrahydropyrrole, etc.

[0003] The raw materials for furfural production are mainly agricultural waste such as corn cobs and rice husks. After pretreatment such as drying and crushing, furfural products are obtained through processes such as hydrolysis extraction under acid and distillation separation. The process mainly includes raw material preparation, hydrolysis extraction, and furfural refining. The aldehyde vapor generated by the hydrolysis reaction is condensed to form a stock solution, which is then concentrated to produce crude furfural. Crude furfural contains components such as water, methanol, acetone, formic acid, acetic acid, and 5-methylfurfural. Through initial distillation, removal of light components, neutralization and deacidification, dehydration, and refining, high-quality furfural products are obtained. Energy conservation and environmental protection factors must also be considered during the production process to ensure sustainable development.

[0004] In the existing process, the tail gas treatment method in furfural production is as follows: After hydrolysis, the pressure in the hydrolysis reactor is reduced to 0.2-0.5 MPa, the bottom discharge valve is opened, and the solid material is discharged to the slag room under gas pressure for steam-slag separation. The separated slag is conveyed to the boiler for use as fuel, and the separated gas is stored in the gas collection chamber. Then, the gas undergoes a series of treatments such as condensation, alkali washing, water washing, and dehumidification. Finally, it is extracted by an induced draft fan and sent to activated carbon adsorption and photocatalytic decomposition treatment before being discharged at a high level through the chimney.

[0005] Problems with existing processes:

[0006] 1) Large investment: It requires the construction of a slag house with a capacity of several thousand cubic meters as a gas-slag separation chamber, as well as exhaust gas treatment facilities.

[0007] 2) High difficulty in sealing the slag room: When slag is discharged, a large amount of gas will leak due to the positive pressure inside the slag room, causing environmental pollution.

[0008] 3) High difficulty in exhaust gas treatment: Because the slag discharge is intermittent, the pressure inside the slag chamber will fluctuate. When the pressure is high, the gas inside the chamber will leak outward, and when the pressure is low, external air will enter, which will increase the difficulty of treatment.

[0009] 4) Environmental protection facilities have complex processes, many pieces of equipment, large investments, and high maintenance costs.

[0010] 5) Poor performance: In the entire furfural production unit, the exhaust gas from the slag room accounts for 90% of the emissions. The composition is complex and the treatment is difficult. Currently used methods such as activated carbon adsorption and photocatalytic decomposition cannot meet the process requirements. Utility Model Content

[0011] The purpose of this utility model is to overcome the above-mentioned problems. To solve these technical problems, this utility model provides the following technical solution:

[0012] A furfural plant slag and tail gas treatment device includes a steam-slag separator (1), an absorption tower (6), a flash tower (8), a first gas-liquid separator (10), and a filter press (15). The feed end of the steam-slag separator (1) is connected to the slag discharge end of the hydrolysis reactor, and the gas discharge end of the steam-slag separator (1) is connected to the gas inlet end of the absorption tower (6) through a steam scrubber (4). The exhaust end of the absorption tower (6) is connected to the input end of the first gas-liquid separator (10) through a first condenser (16), and the gas output end of the first gas-liquid separator (10) is connected to the tail gas treatment system through a blower (7). The bottom of the absorption tower (6) is provided with a bottom storage tank, and the liquid output end of the first gas-liquid separator (10) is connected to the bottom storage tank of the absorption tower (6). The first liquid outlet of the tank is connected to the upper liquid inlet of the absorption tower (6) via the circulating main pump (12). The second liquid outlet of the bottom storage tank of the absorption tower (6) is connected to the lower liquid inlet of the flash tower (8). The third liquid outlet of the bottom storage tank of the absorption tower (6) is connected to the input end of the filter press (15) via the filter press pump (14). The fourth liquid outlet of the bottom storage tank of the absorption tower (6) is connected to the liquid inlet of the steam scrubber (4) via the washing water pump (5). The bottom storage tank of the absorption tower (6) is provided with a sampling port (23) on its side wall. The exhaust end of the flash tower (8) is connected to the vacuum system via the condenser (9) and the second gas-liquid separator. The lower liquid outlet of the flash tower (8) is connected to the upper liquid inlet of the absorption tower (6) and the upper liquid inlet of the flash tower (8) via the circulating auxiliary pump (13) and the cooler (11).

[0013] Preferably, the bottom of the gas-slag separator (1) is provided with a screw conveyor (2), and the screw conveyor (2) is provided with a cooling device.

[0014] Preferably, a washing water pump (5) is provided between the steam scrubber (4) and the absorption tower (6). The input end of the washing water pump (5) is connected to the fourth liquid outlet of the bottom storage tank of the absorption tower (6), the output end of the washing water pump (5) is connected to the liquid inlet of the steam scrubber (4), and the outlet end of the steam scrubber (4) is connected to the bottom storage tank of the absorption tower (6). The steam scrubber (4) has a venturi structure and includes a converging tube, a throat tube, a diverging tube, and a dehydrator connected in sequence.

[0015] Preferably, the filter press (15) is connected to both a water regulating valve (21) and a water discharge regulating valve (22) at its discharge end, and the other end of the water regulating valve (21) is connected to the bottom storage tank of the absorption tower (6).

[0016] Preferably, a circulating main pump (12) is provided on one side of the absorption tower (6), the input end of the circulating main pump (12) is connected to the first liquid outlet end of the bottom storage tank of the absorption tower (6), a liquid phase distributor is provided at the top of the absorption tower (6), and the output end of the circulating main pump (12) is connected to the liquid phase distributor at the top of the absorption tower (6); the internal packing of the absorption tower (6) is grid packing or packing with the same structure and performance as the grid.

[0017] Preferably, a flash tower (8) and a second gas-liquid separator (17) are provided on one side of the absorption tower (6). The first liquid inlet of the flash tower (8) is connected to the second liquid outlet of the bottom storage tank of the absorption tower (6) through a pipeline. The gas outlet of the flash tower (8) is connected to the second gas-liquid separator (17) through a second condenser (9). The gas outlet of the second gas-liquid separator (17) is connected to the vacuum system through a vacuum regulating valve (19). The liquid outlet of the second gas-liquid separator (17) is connected to a water-aldehyde separator.

[0018] Preferably, the flash tower (8) is also connected to a circulating auxiliary pump (13), a cooler (11), and a reflux valve (20). The input end of the circulating auxiliary pump (13) is connected to the liquid outlet end of the flash tower (8), and the output end of the circulating auxiliary pump (13) is connected to the input end of the cooler (11). The output end of the cooler (11) is simultaneously connected to the input end of the reflux valve (20) and the liquid phase distributor at the top of the absorption tower (6). The output end of the reflux valve (20) is connected to the upper end of the flash tower (8).

[0019] Preferably, the flash tower (8) is also connected to a reboiler (18), the input end of the reboiler (18) is connected to the liquid outlet end of the flash tower (8), the output end of the reboiler (18) is connected to the second liquid inlet end of the reboiler of the flash tower (8), the internal packing of the flash tower (8) is grid packing or packing with the same structure and performance as the grid, and there is a liquid phase distributor at the top of the flash tower (8).

[0020] Compared with the prior art, the technical effects of this utility model are as follows:

[0021] 1. This utility model eliminates facilities such as the gas-slag separation chamber in traditional processes and adopts equipment such as gas-slag separators and absorption towers; the slag is discharged using a screw conveyor, which has its own cooling device, which can cool the slag while conveying it, and can also prevent gas leakage from the gas-slag separator, thus reducing environmental pollution.

[0022] 2. This utility model saves on huge investment in the construction of environmental protection equipment and facilities, and can also save on high operating and maintenance costs.

[0023] 3. This utility model can completely absorb and remove slag, methanol, acetone and furfural entrained in the gas. The small amount of exhaust gas after purification and dust removal is discharged by incineration and fully meets the standards.

[0024] 4. This utility model can recover furfural, methanol, acetone and other components in the exhaust aldehyde vapor, thereby improving the recovery rate of furfural. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the furfural device slag and tail gas treatment device of this utility model.

[0026] In the diagram: 1-Steam-slag separator, 2-Screw conveyor, 3-Belt conveyor, 4-Steam scrubber, 5-Scrubber water pump, 6-Absorber, 7-Fan, 8-Flash tower, 9-Second condenser, 10-First gas-liquid separator, 11-Cooler, 12-Main circulating pump, 13-Second circulating auxiliary pump, 14-Filter press pump, 15-Filter press, 16-First condenser, 17-Second gas-liquid separator, 18-Reboiler, 19-Vacuum regulating valve, 20-Reflux valve, 21-Water regulating valve, 22-Water discharge regulating valve, 23-Sampling port. Detailed Implementation

[0027] A furfural plant slag and tail gas treatment device, see [link / reference] Figure 1 The system includes a steam-slag separator 1, an absorption tower 6, a first gas-liquid separator 10, and a filter press 15. The feed end of the steam-slag separator 1 is connected to the slag discharge end of the hydrolysis reactor. A screw conveyor 2 is installed at the bottom of the steam-slag separator 1, and a belt conveyor 3 is installed at the discharge end of the screw conveyor 2. A sampling port 23 is provided on the side wall of the absorption tower 6. The internal packing of the absorption tower 6 is grid packing or packing with the same structure and performance as grid packing. A liquid phase distributor is located at the top of the absorption tower 6.

[0028] The gas discharge end of the steam-sludge separator 1 is connected to the inlet end of the absorption tower 6 via a steam scrubber 4. A washing water pump 5 is installed between the steam scrubber 4 and the absorption tower 6. The input end of the washing water pump 5 is connected to the bottom storage tank of the absorption tower 6, and the output end of the washing water pump 5 is connected to the feed end of the steam scrubber 4. The steam scrubber 4 has a venturi structure and includes a converging tube, a throat, a diverging tube, and a dewatering device connected in sequence.

[0029] The exhaust end of the absorption tower 6 is connected to the input end of the first gas-liquid separator 10 via the first condenser 16. The gas output end of the first gas-liquid separator 10 is connected to the tail gas treatment system via the blower 7. A bottom storage tank is provided at the bottom of the absorption tower 6, and the liquid output end of the first gas-liquid separator 10 is connected to the bottom storage tank of the absorption tower 6. The liquid outlet end of the absorption tower 6 is connected to the input end of the filter press 15 via the filter pump 14. The liquid discharge end of the filter press 15 is connected to both a water regulating valve 21 and a water discharge regulating valve 22. The other end of the water regulating valve 21 is connected to the bottom storage tank of the absorption tower 6.

[0030] A circulating main pump 12 is provided on one side of the absorption tower 6. The input end of the circulating main pump 12 is connected to the bottom storage tank of the absorption tower 6. A liquid phase distributor is provided at the top of the absorption tower 6. The output end of the circulating main pump 12 is connected to the liquid phase distributor at the top of the absorption tower 6.

[0031] A flash evaporator 8 and a second gas-liquid separator 17 are provided on one side of the absorption tower 6. The input end of the flash evaporator 8 is connected to the bottom storage tank of the absorption tower 6 via a pipeline. The gas output end of the flash evaporator 8 is connected to the second gas-liquid separator 17 via a second condenser 9. The gas output end of the second gas-liquid separator 17 is connected to the vacuum system via a vacuum regulating valve 19. The liquid output end of the second gas-liquid separator 17 is connected to a water-aldehyde separator. The internal packing of the flash evaporator 8 is grid packing or packing with the same structure and performance as the grid. A liquid phase distributor is located at the top of the flash evaporator 8. When the furfural content in the liquid phase detected at the sampling port 23 of the bottom storage tank of the absorption tower 6 reaches 0.5% to 5%, the vacuum regulating valve 19 is opened for operation, and the flash evaporator 8 will be controlled at a pressure of -0.05MPa to -0.01MPa.

[0032] The flash distillation tower 8 is also connected to a circulating auxiliary pump 13, a cooler 11, and a reflux valve 20. The input end of the circulating auxiliary pump 13 is connected to the liquid outlet of the flash distillation tower 8, and the output end of the circulating auxiliary pump 13 is connected to the input end of the cooler 11. The output end of the cooler 11 is simultaneously connected to the input end of the reflux valve 20 and the liquid phase distributor at the top of the absorption tower 6. The output end of the reflux valve is connected to the upper end of the flash distillation tower 8. The flash distillation tower 8 is also connected to a reboiler 18. The input end of the reboiler 18 is connected to the liquid outlet of the flash distillation tower 8, and the output end of the reboiler 18 is connected to the side wall of the reboiler 18.

[0033] The beneficial effects of this utility model are:

[0034] 1. This utility model eliminates facilities such as the gas-slag separation chamber in traditional processes and adopts equipment such as gas-slag separators and absorption towers; slag discharge uses a screw conveyor, which can prevent gas leakage from the gas-slag separator and reduce environmental pollution.

[0035] 2. This utility model eliminates the need for massive investment in environmental protection equipment and facilities, saving significant operating and maintenance costs.

[0036] 3. By adding equipment such as a flash tower, this utility model can achieve complete absorption and dust removal of slag, methanol, acetone and furfural entrained in the gas. The small amount of exhaust gas after purification and dust removal is incinerated and discharged, further reducing environmental pollution.

[0037] 4. This utility model can recover furfural, methanol, acetone and other components in the exhaust aldehyde vapor, thereby improving the recovery rate of furfural.

[0038] The working principle of this utility model is as follows: The method for treating the tail gas from the furfural unit's tail gas treatment device includes:

[0039] Step S1: After hydrolysis in the hydrolysis reactor is completed, the pressure in the hydrolysis reactor is reduced to P1 (P1 is 0.06~0.5MPa in this embodiment). The bottom discharge valve of the hydrolysis reactor is opened, and the solid material is discharged to the steam-slag separator 1 under gas pressure. The solid material in the steam-slag separator 1 is separated into steam and slag under pressure P2 (P2 is -0.001MPa~0.1MPa in this embodiment). The slag separated by the steam-slag separator 1 is discharged through the bottom screw conveyor 2 of the steam-slag separator 1 and sent to the boiler for use as fuel by the belt conveyor 3. The gas separated by the steam-slag separator 1 is discharged from the top of the steam-slag separator 1. The main components of the gas are: water vapor, furfural vapor, methanol vapor, acetone vapor, etc. The gas is washed by the steam scrubber 4 and then sent to the absorption tower 6.

[0040] Step S2: Gas from the gas scrubber 4 enters the absorption tower 6 from the bottom and comes into countercurrent contact with the sprayed water at the top of the absorption tower 6. Most of the water vapor, methanol vapor, acetone vapor, furfural vapor, and other gases are absorbed. A small amount of non-condensable vapor is discharged from the top of the absorption tower 6, condensed by the first condenser 16, and then separated by the first gas-liquid separator 10. The non-condensable vapor is sent to the tail gas treatment system by the induced draft fan 7 for tail gas treatment. The condensate in the first gas-liquid separator 10 flows back to the bottom storage tank of the absorption tower 6. The water in the bottom storage tank of the absorption tower 6 is pressurized by the circulating main pump 12 and then sprayed evenly through the liquid phase distributor at the top of the absorption tower 6.

[0041] Step S3: The slag entrained in the gas from the steam scrubber 4 is removed after being washed by the spray water in the absorption tower 6. When the slag content in the spray water reaches a certain level (solid content 0.1% to 3%), it is pressurized by the filter press pump 14 and transported to the filter press 15 to remove the slag from the spray water. The slag is used as biofuel in the boiler, and the purified water is returned to the storage tank of the absorption tower 6 for recycling. When the liquid level in the storage tank of the absorption tower 6 is high, the water regulating valve 21 is closed and the water discharge regulating valve 22 is opened to discharge the excess water to the sewage treatment plant.

[0042] Step S4: Water vapor, methanol vapor, acetone vapor, and furfural vapor entrained in the gas from the steam scrubber 4 are absorbed after being washed by the spray water in the absorption tower 6. After the concentration of furfural and other components in the spray water reaches M (0.5% to 5% in this embodiment) at the sampling port 23 of the absorption tower 6, the vacuum regulating valve 19 and the reflux valve 20 are opened; the flash tower 8 is started, and the mixture of furfural, water, methanol, acetone and other components is flashed out under the pressure P3 (-0.05 to -0.01 MPa in this embodiment). After being condensed by the second condenser 9 of the flash tower 8, it enters the second gas-liquid separator 17. After separation, the uncondensed vapor is sent to the vacuum system through the vacuum regulating valve 19, and the condensate is separated in the water-aldehyde separator. The high-temperature water that absorbs the steam in the absorption tower 6 is pressurized by the circulating auxiliary pump 13 and cooled by the cooler 11 before returning to the absorption tower 6 for recycling.

[0043] Through the above steps, the slag, methanol, acetone, and furfural entrained in the gas can be completely absorbed and dust removed. The small amount of exhaust gas after purification and dust removal is then incinerated and discharged, further reducing environmental pollution. Furthermore, furfural, methanol, acetone, and other components in the exhaust gas can be recovered, improving the furfural recovery rate.

[0044] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

Claims

1. A furfural plant decanter tail gas treatment apparatus, characterized by, The device comprises a steam residue separator (1), an absorption tower (6), a flash tower (8), a first gas-liquid separation tank (10) and a filter press (15), the feed end of the steam residue separator (1) is connected to the residue discharge end of a hydrolysis kettle, the gas discharge end of the steam residue separator (1) is connected to the gas inlet end of the absorption tower (6) through a steam scrubber (4); the exhaust end of the absorption tower (6) is connected to the input end of the first gas-liquid separation tank (10) through a first condenser (16), the gas output end of the first gas-liquid separation tank (10) is connected to a tail gas treatment system through a fan (7), the bottom of the absorption tower (6) is provided with a bottom storage tank, the liquid output end of the first gas-liquid separation tank (10) is connected to the bottom storage tank of the absorption tower (6); the first liquid outlet end of the bottom storage tank of the absorption tower (6) is connected to the upper liquid inlet end of the absorption tower (6) through a circulating main pump (12), the second liquid outlet end of the bottom storage tank of the absorption tower (6) is connected to the lower liquid inlet end of the flash tower (8), the third liquid outlet end of the bottom storage tank of the absorption tower (6) is connected to the input end of the filter press (15) through a filter press pump (14), the fourth liquid outlet end of the bottom storage tank of the absorption tower (6) is connected to the liquid inlet end of the steam scrubber (4) through a washing water pump (5), the sidewall of the bottom storage tank of the absorption tower (6) is provided with a sampling port (23); the exhaust end of the flash tower (8) is connected to a vacuum system through a condenser (9) and a second gas-liquid separation tank, the lower liquid outlet end of the flash tower (8) is connected to the upper liquid inlet end of the absorption tower (6) and the upper liquid inlet end of the flash tower (8) through a circulating auxiliary pump (13) and a cooler (11).

2. The furfural plant de-sludging off-gas treatment apparatus of claim 1, wherein, The bottom of the steam residue separator (1) is provided with a spiral discharging machine (2), and the spiral discharging machine (2) is provided with a cooling device.

3. The furfural plant de-sludging off-gas treatment apparatus of claim 2, wherein, The steam scrubber (4) and the absorption tower (6) are provided with a washing water pump (5), the input end of the washing water pump (5) is connected to the fourth liquid outlet end of the bottom storage tank of the absorption tower (6), the output end of the washing water pump (5) is connected to the liquid inlet end of the steam scrubber (4), and the outlet end of the steam scrubber (4) is connected to the bottom storage tank of the absorption tower (6); the steam scrubber (4) is a Venturi structure and comprises a converging tube, a throat tube, a diverging tube and a dehydrator connected in sequence.

4. The furfural plant de-sludging off-gas treatment apparatus of claim 3, wherein, The liquid discharge end of the filter press (15) is connected to a water regulating valve (21) and a water discharge regulating valve (22) at the same time, and the other end of the water regulating valve (21) is connected to the bottom storage tank of the absorption tower (6).

5. The furfural plant de-sludging off-gas treatment apparatus of claim 4, wherein, One side of the absorption tower (6) is provided with a circulating main pump (12), the input end of the circulating main pump (12) is connected to the first liquid outlet end of the bottom storage tank of the absorption tower (6), the top of the absorption tower (6) is provided with a liquid phase distributor, and the output end of the circulating main pump (12) is connected to the liquid phase distributor at the top of the absorption tower (6); the internal filler of the absorption tower (6) is a grid filler or a filler with the same structure and performance as the grid structure.

6. The furfural plant de-sludging off-gas treatment apparatus of claim 5, wherein, The side of the absorption tower (6) is provided with a flash tower (8) and a second gas-liquid separation tank (17), the first liquid inlet end of the tower kettle of the flash tower (8) is connected with the second liquid outlet end of the bottom storage tank of the absorption tower (6) through a pipeline, the gas output end of the flash tower (8) is connected with the second gas-liquid separation tank (17) through a second condenser (9), the gas output end of the second gas-liquid separation tank (17) is connected with a vacuum system through a vacuum regulating valve (19), and the liquid output end of the second gas-liquid separation tank (17) is connected with a water-aldehyde separator.

7. The furfural plant de-sludging off-gas treatment apparatus of claim 6, wherein, The flash tower (8) is also connected with a circulating auxiliary pump (13), a cooler (11) and a reflux valve (20), the input end of the circulating auxiliary pump (13) is connected with the liquid outlet end of the flash tower (8), the output end of the circulating auxiliary pump (13) is connected with the input end of the cooler (11), the output end of the cooler (11) is connected with the input end of the reflux valve (20) and the liquid phase distributor at the top of the absorption tower (6) at the same time, and the output end of the reflux valve (20) is connected with the upper end of the flash tower (8).

8. The furfural plant de-sludging off-gas treatment apparatus of claim 7, wherein, The flash tower (8) is also connected with a reboiler (18), the input end of the reboiler (18) is connected with the liquid outlet end of the flash tower (8), the output end of the reboiler (18) is connected with the second liquid inlet end of the tower kettle of the flash tower (8), the internal packing of the flash tower (8) is grid packing or packing consistent with the grid structure and performance, and the top of the flash tower (8) is provided with a liquid phase distributor.

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