Furfural device deslagging tail gas treatment device and deslagging tail gas treatment method

Abstract

The invention discloses a furfural device slag discharge 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 slag discharge end of a hydrolysis kettle, and the gas discharge 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. Meanwhile, the invention further discloses a deslagging tail gas treatment method, equipment such as the steam-slag separator, the absorption tower, the flash tower and the filter press is adopted in the device, huge environment-friendly equipment and facility construction investment is saved, and high operation and maintenance cost is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass utilization, and particularly relates to a slag tail gas treatment device and a slag tail gas treatment method for a furfural device. Background Art

[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 primarily used as an industrial solvent and can also be used to produce furfuryl alcohol, furoic acid, tetrahydrofuran, γ-valerolactone, pyrrole, and tetrahydropyrrole.

[0003] The raw materials for furfural production primarily come from agricultural waste such as corn cobs and rice husks. After pretreatment such as drying and pulverization, furfural products are obtained through processes such as hydrolysis extraction under acid conditions and distillation separation. The process primarily 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 gross aldehyde. Gross aldehyde contains components such as water, methanol, acetone, formic acid, acetic acid, and 5-methylfurfural. Through initial distillation, light removal, neutralization and deacidification, dehydration, and refining, high-quality furfural products are obtained. Energy conservation and environmental protection are also important considerations during the production process to ensure sustainable development.

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

[0005] Problems with existing processes:

[0006] 1) Large investment: It is necessary to build a slag room of several thousand cubic meters as a steam-slag separation chamber, and also to build tail gas treatment facilities.

[0007] 2) The slag room is difficult to seal: When discharging slag, a large amount of gas will leak due to the positive pressure in the slag room, causing environmental pollution.

[0008] 3) Difficulty in tail gas treatment: Since slag discharge is intermittent, the pressure in the slag room will be high and low. When the pressure is high, the gas in the room will leak out, and when the pressure is low, the outside air will enter. The entry of air 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 effect: In the entire furfural production plant, slag room tail gas emissions account for 90%, with complex composition and high difficulty in treatment. Currently common measures such as activated carbon adsorption and photocatalytic decomposition cannot meet the process requirements. Summary of the Invention

[0011] The purpose of the present invention is to overcome the above problems. To solve the above technical problems, the present invention provides the following technical solutions:

[0012] The first aspect of the present invention provides a furfural device slag discharge tail gas treatment device, comprising a steam-slag separator (1), an absorption tower (6), a flash tower (8), a first gas-liquid separation tank (10) and a filter press (15), wherein the feed end of the steam-slag separator (1) is connected to the slag discharge end of the hydrolysis kettle, 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 separation tank (10) through a first condenser (16), the gas output end of the first gas-liquid separation tank (10) is connected to the tail gas treatment system through a fan (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 separation tank (10) is connected to the bottom storage tank of the absorption tower (6); the absorption tower The first liquid outlet of the bottom storage tank of the absorption tower (6) is connected to the upper liquid inlet of the absorption tower (6) through the circulation 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) through 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) through the washing water pump (5), and a sampling port (23) is provided on the side wall of the bottom storage tank of the absorption tower (6); the exhaust end of the flash tower (8) is connected to the vacuum system through the condenser (9) and the second gas-liquid separation tank, and the liquid outlet of the lower end 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) through the circulation auxiliary pump (13) and the cooler (11).

[0013] Preferably, a screw discharger (2) is provided at the bottom of the steam-slag separator (1), and the screw discharger (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 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, comprising a convergent pipe, a throat pipe, a divergent pipe and a dehydrator connected in sequence.

[0015] Preferably, the discharge end of the filter press (15) is connected to a water regulating valve (21) and a water discharge regulating valve (22), 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 storage tank at the bottom of the absorption tower (6), a liquid phase distributor is provided on 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 filler of the absorption tower (6) is a grid filler or a filler with the same structure and performance as the grid.

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

[0018] Preferably, the flash tower (8) is further 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), 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); the flash tower (8) is further 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 flash tower (8), the internal filler of the flash tower (8) is a grid filler or a filler with the same structure and performance as the grid, and a liquid phase distributor is provided on the top of the flash tower (8); when the sampling port (23) of the storage tank at the bottom of the absorption tower (6) detects that the mass content of furfural in the liquid phase reaches 0.5% to 5%, the vacuum regulating valve (19) is opened to put the flash tower (8) into use and control the pressure at -0.05MPa to -0.01MPa.

[0019] The second aspect of the present invention is to provide a method for treating slag tail gas using a furfural device-based slag tail gas treatment device, comprising:

[0020] Step S1: After the hydrolysis in the hydrolysis kettle is completed, the pressure of the hydrolysis kettle is reduced to 0.06-0.5 MPa, the bottom discharge valve of the hydrolysis kettle is opened, and the solid material is discharged to the steam-slag separator (1) under the pressure of the pressurized gas. The solid material in the steam-slag separator (1) is subjected to steam-slag separation at a pressure of -0.001 MPa-0.1 MPa; the steam separated by the steam-slag separator (1) is discharged from the top of the steam-slag separator (1), washed by the steam washer (4), and then transported to the absorption tower (6);

[0021] Step S2: The gas from the steam scrubber (4) enters the absorption tower (6) from the bottom of the absorption tower (6), and contacts the spray water at the top of the absorption tower (6) in reverse, wherein most of the gas is absorbed by the spray water, and a small amount of non-condensable steam is discharged from the top of the absorption tower (6), condensed by the first condenser (16), and then separated by the first gas-liquid separation tank (10). The non-condensable steam is sent to the tail gas treatment system by the induced draft fan (7) for treatment, and the condensate in the first gas-liquid separation tank (10) is refluxed to the storage tank at the bottom of the absorption tower (6);

[0022] Step S3: The slag carried in the gas from the steam scrubber (4) is removed after being washed with spray water in the absorption tower (6). When the content of the washed slag in the spray water reaches a certain content (solid content 0.1% to 3%), it is pressurized by the filter press pump (14) and then transported to the filter press (15) to remove the slag in the spray water; the slag is sent to the boiler as biofuel, and the purified water is returned to the bottom storage tank of the absorption tower (6) for recycling. When the liquid level in the bottom storage tank of the absorption tower (6) is high, the water regulating valve (22) is opened to send the water to sewage treatment;

[0023] Preferably, in step S1: the slag separated by the steam-slag separator (1) is discharged through a screw discharger (2) at the bottom of the steam-slag separator (1), the screw discharger (2) is provided with a cooling device, and then the slag is sent to the boiler by a belt conveyor (3) for use as fuel;

[0024] In step S2: the water in the storage tank at the bottom of the absorption tower (6) is pressurized by the circulating main pump (12) and then uniformly sprayed out through the liquid phase distributor at the top of the absorption tower (6);

[0025] In step S3: when the liquid level in the bottom 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 excess water to sewage treatment.

[0026] As an advantage, the method further includes step S4:

[0027] Step S4: The water vapor, methanol vapor, acetone vapor, and furfural vapor carried in the gas from the steam scrubber (4) are washed and absorbed by the spray water in the absorption tower (6). The spray water temperature increases, is pressurized by the circulation auxiliary pump (13), cooled by the cooler (11), and then returned to the absorption tower (6) for recycling. After the furfural and other components in the spray water reach a concentration of 0.5% to 5% through the sampling port (23) of the absorption tower (6), the flash tower (8) is put into use, the vacuum regulating valve (19) and the reflux valve (20) are opened, and a mixture of furfural, steam, methanol, acetone and other components is flashed at a pressure of -0.05 to -0.01 MPa. The flash gas is discharged from the exhaust end of the flash tower (8), condensed by the second condenser (9), and enters the second gas-liquid separation tank (17). After separation, the uncondensed steam is transported to the vacuum system through the vacuum regulating valve (19), and the condensate is separated in the water-formaldehyde separation tank.

[0028] Compared with the prior art, the technical effects of the present invention are:

[0029] 1. The present invention eliminates the steam-slag separation chamber and other facilities in the traditional process and adopts steam-slag separators, absorption towers and other equipment; a spiral discharging machine is used for slag discharge. The spiral discharging machine has a built-in cooling device, which can cool the slag while conveying it, and can also isolate the gas leakage of the steam-slag separator to reduce environmental pollution.

[0030] 2. The present invention saves huge investment in the construction of environmental protection equipment and facilities, and can also save high operating and maintenance costs.

[0031] 3. The present invention can achieve complete absorption and dust removal of slag, methanol, acetone and furfural entrained in the gas, and the small amount of tail gas after purification and dust removal is discharged through incineration, which fully meets the emission standards.

[0032] 4. The present invention can recover furfural, methanol, acetone and other components in the slag discharge aldehyde steam, thereby improving the recovery rate of furfural. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of a furfural device slag discharge tail gas treatment device of the present invention;

[0034] In the figure: 1-steam-slag separator, 2-screw discharging machine, 3-belt conveyor, 4-steam scrubber, 5-washing water pump, 6-absorption tower, 7-fan, 8-flash tower, 9-second condenser, 10-first gas-liquid separation tank, 11-cooler, 12-circulation main pump, 13-circulation auxiliary pump, 14-filter press pump, 15-filter press, 16-first condenser, 17-second gas-liquid separation tank, 18-reboiler, 19-vacuum regulating valve, 20-reflux valve, 21-water regulating valve, 22-water discharge regulating valve, 23-sampling port. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to specific embodiments.

[0036] Example 1

[0037] A furfural plant slag tail gas treatment device, see Figure 1 The system comprises a steam-slag separator 1, an absorption tower 6, a first gas-liquid separation tank 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 kettle. A screw discharger 2 is provided at the bottom of the steam-slag separator 1, and a belt conveyor 3 is provided at the discharge end of the screw discharger 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 a grid packing or a packing with the same structure and performance as the grid. A liquid phase distributor is provided at the top of the absorption tower 6.

[0038] The gas discharge end of the steam-slag separator 1 is connected to the air inlet end of the absorption tower 6 through the steam scrubber 4. 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 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 is a Venturi structure, including a convergent pipe, a throat pipe, a divergent pipe and a dehydrator connected in sequence.

[0039] The exhaust end of the absorption tower 6 is connected to the input end of the first gas-liquid separator 10 via a first condenser 16. The gas output end of the first gas-liquid separator 10 is connected to the exhaust gas treatment system via a blower 7. A bottom storage tank is provided at the bottom of the absorption tower 6. 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 a filter press 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.

[0040] 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, and a liquid phase distributor is provided on 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.

[0041] A flash tower 8 and a second gas-liquid separator 17 are installed on one side of the absorption tower 6. The input of the flash tower 8 is connected to the bottom storage tank of the absorption tower 6 via a pipeline. The gas output of the flash tower 8 is connected to the second gas-liquid separator 17 via a second condenser 9. The gas output of the second gas-liquid separator 17 is connected to the vacuum system via a vacuum control valve 19, and the liquid output of the second gas-liquid separator 17 is connected to the water-aldehyde separator. The internal packing of the flash tower 8 is a grid packing or a packing with the same structure and performance as the grid. A liquid distributor is installed at the top of the flash tower 8. When the furfural content in the liquid phase reaches 0.5% to 5% by mass at the sampling port 23 of the bottom storage tank of the absorption tower 6, the vacuum control valve 19 is opened and the flash tower 8 is put into operation, controlling the pressure at -0.05 MPa to -0.01 MPa. By adding equipment such as the flash tower, 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, further reducing environmental pollution.

[0042] 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 of the flash tower 8, 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, and the output end of the reflux valve is connected to the upper end of the flash tower 8. The flash 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 tower 8, and the output end of the reboiler 18 is connected to the side wall of the reboiler 18.

[0043] The device of the present invention eliminates the steam-slag separation chamber and other facilities found in traditional processes, instead employing a steam-slag separator and absorption tower. A spiral discharger is used for slag discharge, which prevents gas leakage from the steam-slag separator and reduces environmental pollution. This eliminates the need for extensive investment in environmental protection equipment and facilities, saving significant operating and maintenance costs. Furthermore, the device of the present invention can recover furfural, methanol, acetone, and other components from the aldehyde vapor discharged from the slag, thereby improving the recovery rate of furfural.

[0044] Example 2

[0045] A method for treating slag tail gas from a furfural device according to the first embodiment includes:

[0046] Step S1: After the hydrolysis in the hydrolysis kettle is completed, the pressure of the hydrolysis kettle is reduced to P1 (P1 is 0.06-0.5 MPa in this embodiment), and the bottom discharge valve of the hydrolysis kettle is opened. The solid material is discharged into the steam-slag separator 1 under the steam pressure. The solid material in the steam-slag separator 1 is subjected to steam-slag separation under the pressure of P2 (P2 is -0.001 MPa-0.1 MPa in this embodiment); the slag separated by the steam-slag separator 1 is discharged through the bottom screw discharger 2 of the steam-slag separator 1 and sent to the boiler by the belt conveyor 3 for use as fuel; 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.

[0047] Step S2: The gas from the steam scrubber 4 enters the absorption tower 6 from the bottom of the absorption tower 6 and contacts the water sprayed on the top of the absorption tower 6 in reverse direction, wherein most of the water vapor, methanol vapor, acetone vapor, furfural vapor and other gases are absorbed; a small amount of non-condensable steam 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 steam is sent to the exhaust gas treatment system by the induced draft fan 7 for exhaust gas treatment, and the condensate in the first gas-liquid separator 10 is refluxed 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 evenly sprayed out through the liquid phase distributor at the top of the absorption tower 6.

[0048] Step S3: The slag entrained in the gas from the steam scrubber 4 is removed after being washed with spray water in the absorption tower 6. When the slag content in the spray water reaches a certain content (solid content 0.1% to 3%), it is pressurized by the filter press pump 14 and then transported to the filter press 15 to remove the slag in the spray water; the slag is sent to the boiler as biofuel, 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.

[0049] Step S4: The water vapor, methanol vapor, acetone vapor, and furfural vapor carried by the gas from the steam scrubber 4 are absorbed after being washed with spray water in the absorption tower 6. After the furfural and other components in the spray water reach a concentration of M (M is 0.5% to 5% in the present embodiment) through 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 to flash a mixture of furfural, water, methanol, acetone and other components at a pressure P3 (P3 is -0.05 to -0.01 MPa in the present embodiment), which is condensed in the second condenser 9 of the flash tower 8 and enters the second gas-liquid separator 17 for separation. The uncondensed steam is transported to the vacuum system through the vacuum regulating valve 19, and the condensate is separated in the water-aldehyde separator; the high-temperature water absorbed by the steam in the absorption tower 6 is pressurized by the circulation auxiliary pump 13 and cooled by the cooler 11 before being returned to the absorption tower 6 for recycling.

[0050] The process of the present invention can achieve complete absorption and dust removal of slag, methanol, acetone and furfural entrained in the gas, and a small amount of tail gas after purification and dust removal is discharged through incineration, thereby further reducing environmental pollution.

[0051] Obviously, the embodiments described above are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

Claims

1. A furfural device slag tail gas treatment device, characterized in that: The invention comprises a steam-slag separator (1), an absorption tower (6), a flash tower (8), a first gas-liquid separation tank (10) and a filter press (15), wherein the feed end of the steam-slag separator (1) is connected to the slag discharge end of the hydrolysis kettle, 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 separation tank (10) through a first condenser (16), the gas output end of the first gas-liquid separation tank (10) is connected to the tail gas treatment system through a fan (7), a bottom storage tank is provided at the bottom of the absorption tower (6), 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 bottom storage tank of the absorption tower (6) through a first condenser (16). The main circulation pump (12) is connected to the upper liquid inlet of the absorption tower (6); 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) through a 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) through a washing water pump (5); and a sampling port (23) is provided on the side wall of the bottom storage tank of the absorption tower (6); the exhaust end of the flash tower (8) is connected to the vacuum system through a condenser (9) and a second gas-liquid separation tank; 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) through a circulation auxiliary pump (13) and a cooler (11).

2. The furfural device slag discharge tail gas treatment device according to claim 1, characterized in that: A screw discharger (2) is provided at the bottom of the steam-slag separator (1), and the screw discharger (2) is provided with a cooling device.

3. The furfural device slag discharge tail gas treatment device according to claim 2, characterized in that: 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 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, comprising a convergent pipe, a throat pipe, a divergent pipe and a dehydrator which are connected in sequence.

4. The furfural device slag discharge tail gas treatment device according to claim 3, characterized in that: 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 device slag tail gas treatment device according to claim 4, characterized in that: 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 storage tank at the bottom of the absorption tower (6), a liquid phase distributor is provided on the top of the absorption tower (6), and the output end of the circulating main pump (12) is connected to the liquid phase distributor on 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.

6. The furfural device slag tail gas treatment device according to claim 5, characterized in that: A flash tower (8) and a second gas-liquid separation tank (17) are provided on one side of the absorption tower (6); the first liquid inlet end of the bottom of the flash tower (8) is connected to the second liquid outlet end of the storage tank at the bottom of the absorption tower (6) through a pipeline; the gas output end of the flash tower (8) is connected to 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 to a vacuum system through a vacuum regulating valve (19); and the liquid output end of the second gas-liquid separation tank (17) is connected to a water-aldehyde separator.

7. The furfural device slag tail gas treatment device according to claim 6, characterized in that: 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); 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); 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 flash tower (8); the internal filler of the flash tower (8) is a grid filler or a filler with the same structure and performance as the grid; and the top of the flash tower (8) is provided with a liquid phase distributor.

8. A method for treating slag tail gas from a furfural device according to any one of claims 1 to 7, characterized in that: include: Step S1: After the hydrolysis in the hydrolysis kettle is completed, the pressure of the hydrolysis kettle is reduced to 0.06-0.5 MPa, and the bottom discharge valve of the hydrolysis kettle is opened, and the solid materials are discharged to the steam-slag separator (1) under the pressure of the pressure gas. The solid materials in the steam-slag separator (1) are separated from the steam-slag at a pressure of -0.001 MPa to 0.1 MPa; the steam separated by the steam-slag separator (1) is discharged from the top of the steam-slag separator (1), washed by the steam washer (4), and then transported to the absorption tower (6); Step S2: The steam from the steam scrubber (4) enters the absorption tower (6) from the bottom of the absorption tower (6) and contacts the spray water at the top of the absorption tower (6) in reverse direction, wherein most of the steam is absorbed by the spray water, and a small amount of non-condensable steam is discharged from the top of the absorption tower (6), condensed by the first condenser (16), and then separated by the first gas-liquid separation tank (10), and the non-condensable steam is sent to the tail gas treatment system by the induced draft fan (7) for treatment, and the condensate in the first gas-liquid separation tank (10) is refluxed to the storage tank at the bottom of the absorption tower (6); Step S3: The slag entrained in the steam from the steam scrubber (4) is removed after being washed with spray water in the absorption tower (6). When the slag content washed out in the spray water reaches a certain content (solid content 0.1% to 3%), it is pressurized by a filter press pump (14) and transported to a filter press (15) to remove the slag in the spray water; the slag is sent to the boiler as biofuel, and the purified water is returned to the bottom storage tank of the absorption tower (6) for recycling. When the liquid level of the bottom storage tank of the absorption tower (6) is high, the water regulating valve (22) is opened to send the water to sewage treatment.

9. The method for treating slag tail gas based on the slag tail gas treatment device of the furfural device according to claim 8, characterized in that: In step S1: the slag separated by the steam-slag separator (1) is discharged through a screw discharger (2) at the bottom of the steam-slag separator (1), the screw discharger (2) being provided with a cooling device, and then sent to a boiler by a belt conveyor (3) for use as fuel; In step S2: the water in the storage tank at the bottom of the absorption tower (6) is pressurized by the circulating main pump (12) and then uniformly sprayed out through the liquid phase distributor at the top of the absorption tower (6); In step S3: when the liquid level in the bottom 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 excess water to sewage treatment.

10. The method for treating slag tail gas based on the furfural device slag tail gas treatment device according to claim 9, characterized in that: The step S4 is also included: Step S4: the water vapor, methanol vapor, acetone vapor and furfural vapor entrained in the gas from the steam scrubber (4) are washed and absorbed by the spray water in the absorption tower (6). The temperature of the spray water will increase. The spray water is pressurized by the circulation auxiliary pump (13) and cooled by the cooler (11) before returning to the absorption tower (6) for recycling. After the furfural and other components in the spray water reach a concentration of 0.5% to 5% through the sampling port (23) of the absorption tower (6), the flash tower (8) is put into use, the vacuum regulating valve (19) and the reflux valve (20) are opened, and a mixture of furfural, steam, methanol, acetone and other components is flashed out at a pressure of -0.05 to -0.01 MPa. The flash gas is discharged from the exhaust end of the flash tower (8), condensed by the second condenser (9) and enters the second gas-liquid separation tank (17). After separation, the uncondensed steam is transported to the vacuum system through the vacuum regulating valve (19), and the condensate is separated by the water-dehydration aldehyde separation tank.

Images