Waste heat recovery device for plant fiber raw material drying tail gas

Abstract

The waste heat recovery device for the plant fiber raw material drying tail gas comprises a heat carrying agent storage tank, a tail gas heat exchange tower and an air heat exchange tower. The heat-carrying agent storage tank is used for storing a heat-carrying agent, the tail gas heat exchange tower is used for heat exchange between hot tail gas and a cold heat-carrying agent, and the air heat exchange tower is used for heat exchange between a hot heat-carrying agent and cold air. In the heat exchange process, the tail gas heat exchange tower and the air heat exchange tower are connected with each other, a continuous working state of the two towers is formed, continuous heat exchange of hot tail gas and cold air is achieved, and therefore waste heat recovery of the dried tail gas is achieved. According to the waste heat recovery device for the plant fiber raw material drying tail gas, waste heat recovery of the drying tail gas is convenient, and the waste heat recovery efficiency is high.

Description

TECHNICAL FIELD

[0001] The utility model relates to a waste heat recovery technical field especially relates to a kind of waste heat recovery devices of plant fiber raw material drying tail gas. BACKGROUND

[0002] Plant fiber raw material is renewable biomass raw material, and monosaccharide is obtained by hydrolysis with it as raw material, and then feed protein, food, chemical product etc. can be produced by fermentation process or chemical process, which can reduce carbon emissions. There are various methods for hydrolysis of plant fiber raw material, and using concentrated sulfuric acid to hydrolyze plant fiber raw material is one of the commonly used methods, but sugar gum layer is easily formed on the surface of plant fiber raw material during concentrated sulfuric acid hydrolysis process, which prevents the penetration of concentrated sulfuric acid into the raw material, resulting in a significant reduction in hydrolysis speed. Therefore, it is necessary to crush the plant fiber raw material into 80-100 mesh powder. However, due to the flexibility of plant fiber raw material, direct crushing may cause heating, ignition and high energy consumption. Therefore, a brittle agent solution needs to be added for pretreatment before crushing, and the plant fiber raw material after drying is very easy to crush, greatly saving the energy consumption and time of crushing. However, the drying process consumes a certain amount of energy, and the drying tail gas reaches 70-80 DEG C, so it is necessary to recover the waste heat of the tail gas and recycle it for drying process to reduce the energy consumption of drying.

[0003] In the prior art, boiler tail gas waste heat recovery generally uses heat exchanger type air preheater, such as plate type flue gas heat exchanger, tube type flue gas heat exchanger and rotary flue gas heat exchanger. These flue gas heat exchangers are hot flue gas tail gas and cold air flowing in separate channels, and the heat storage and heat release of the heat exchanger transfers the heat of the flue gas to the cold air to become hot air, which is then sucked into the boiler by the air blower to achieve energy saving. This method uses indirect heat exchange between gas and gas, and the total heat exchange coefficient is very low, the equipment is large and the cost is high, which affects the recovery and application of tail gas waste heat.

[0004] Therefore, it is necessary to provide a waste heat recovery device for plant fiber raw material drying tail gas, which is simple in structure, convenient in waste heat recovery and high in waste heat recovery efficiency. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a waste heat recovery device for plant fiber raw material drying tail gas, which is simple in structure, convenient in waste heat recovery and high in waste heat recovery efficiency.

[0006] To achieve the above-mentioned purpose, the utility model provides a waste heat recovery device for plant fiber raw material drying tail gas, which comprises:

[0007] The heat-carrying agent storage tank comprises a first outlet and a first inlet, the first outlet is used for the heat-carrying agent to flow out, and the first inlet is used for the heat-carrying agent to flow in;

[0008] The tail gas heat exchange tower comprises, from top to bottom, a tail gas outlet, a first gas-liquid separator, a second inlet, a first liquid distributor, a first packing zone, a tail gas inlet, a clarification section, a second outlet and a condensed water outlet; the cold-carrying heat agent flows into the tail gas heat exchange tower from the second inlet and passes through the first liquid distributor, the hot tail gas enters the tail gas heat exchange tower from the tail gas inlet and directly exchanges heat with the cold-carrying heat agent, so that the hot tail gas becomes cold tail gas and passes through the first gas-liquid separator upwards, the liquid in the cold tail gas is collected by the first gas-liquid separator and then flows back to the first liquid distributor, and the cold tail gas is discharged from the tail gas outlet; the cold-carrying heat agent becomes hot-carrying heat agent after completing heat exchange, the hot-carrying heat agent falls from the first packing zone into one side of the clarification section and realizes oil-water separation, the hot-carrying heat agent is collected at the second outlet and then flows out, and the condensed water is discharged from the condensed water outlet.

[0009] The air heat exchange tower comprises, from top to bottom, a hot air outlet, a second gas-liquid separator, a third inlet, a second liquid distributor, a second packing zone, a cold air inlet and a third outlet, the third inlet is communicated with the second outlet, the third outlet is communicated with the first inlet or the second inlet, and the first outlet or the third outlet is communicated with the second inlet; the cold-carrying heat agent flows into the air heat exchange tower from the third inlet and enters the second liquid distributor, the cold air enters the air heat exchange tower from the cold air inlet and directly exchanges heat with the downward flowing cold-carrying heat agent, the cold air becomes hot air and passes through the second gas-liquid separator, the liquid in the hot air is collected by the second gas-liquid separator and then flows back to the second liquid distributor, the hot air is discharged from the hot air outlet, and the cold-carrying heat agent becomes hot-carrying heat agent after completing heat exchange and is discharged from the third outlet.

[0010] Compared with the prior art, the plant fiber raw material drying tail gas waste heat recovery device has the advantages that the plant fiber raw material drying tail gas waste heat recovery device directly exchanges the heat of the heat carrying agent with the drying tail gas and the air, greatly improves the heat exchange efficiency, reduces the equipment investment, and compared with the traditional waste heat recovery device which recovers the waste heat of the drying tail gas through indirect heat exchange, the plant fiber raw material drying tail gas waste heat recovery device is convenient in waste heat recovery of the drying tail gas and high in waste heat recovery efficiency.

[0011] Preferably, the third outlet is connected with the second inlet through a first pipeline, and a first circulating pump is arranged on the first pipeline and used for conveying the cold heat carrying agent from the third outlet to the first inlet or the second inlet.

[0012] Preferably, the first outlet is connected with a discharge pipeline, the discharge pipeline is connected with the first pipeline and connected with an input end of the first circulating pump.

[0013] Preferably, the second outlet is connected with the third inlet through a second pipeline, and a second circulating pump is arranged on the second pipeline and used for conveying the hot heat carrying agent from the second outlet to the third inlet.

[0014] Preferably, a flow collecting plate is arranged between the first packing zone and the clarification section, and the hot-carrying agent falling from the first packing zone is guided to one side of the clarification section by the flow collecting plate, and the second outlet is arranged on the side of the clarification section away from the flow collecting plate.

[0015] Preferably, a plurality of vertical porous plates are arranged in the clarification section, and the plate surfaces of the porous plates are perpendicular to the second outlet.

[0016] Preferably, the first packing zone and the second packing zone are both filled with packing, and the first liquid distributor and the second liquid distributor are used to uniformly distribute the hot-carrying agent on the top of the corresponding packing.

[0017] Preferably, the first liquid distributor is rotatably arranged in the tail gas heat exchange tower, and the second liquid distributor is rotatably arranged in the air heat exchange tower, and the first liquid distributor and the second liquid distributor both include a plurality of dry pipes, each dry pipe includes a plurality of branch pipes, and each branch pipe is uniformly provided with a plurality of small holes.

[0018] Preferably, the packing is made of plastic material, or the packing is made of ceramic material.

[0019] Preferably, the first inlet is provided with an openable and closable first valve, the first outlet is provided with an openable and closable second valve, the second inlet is provided with an openable and closable third valve, the second outlet is provided with an openable and closable fourth valve, the third inlet is provided with an openable and closable fifth valve, and the third outlet is provided with an openable and closable sixth valve. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Figure 1 is a structural schematic view of a waste heat recovery device for plant fiber raw material drying tail gas according to an embodiment of the present application.

[0022] Figure 2 is Figure 1 a structural schematic view of a tail gas heat exchange tower in the waste heat recovery device.

[0023] Figure 3 is Figure 1 a structural schematic view of an air heat exchange tower in the waste heat recovery device.

[0024] Marked legend:

[0025] 100, waste heat recovery device for plant fiber raw material drying tail gas;

[0026] 10, heat carrier tank; 11, first inlet; 111, first valve; 12, first outlet; 121, second valve;

[0027] 20, tail gas heat exchange tower; 21, second inlet; 211, third valve; 22, first gas-liquid separator; 23, tail gas outlet; 24, first liquid distributor; 25, first packing zone; 201, packing; 26, tail gas inlet; 27, collecting plate; 28, clarification section; 281, perforated plate; 29, second outlet; 291, fourth valve; 210, condensed water outlet; 2101, condensed water valve;

[0028] 30, air heat exchange tower; 31, third inlet; 311, fifth valve; 32, second gas-liquid separator; 33, hot air outlet; 34, second liquid distributor; 35, second packing zone; 36, cold air inlet; 37, third outlet; 371, sixth valve;

[0029] 40, first circulating pump; 41, first pipeline; 42, discharge pipeline;

[0030] 50, second circulating pump; 51, second pipeline. DETAILED DESCRIPTION

[0031] In order to explain the technical content and structural features of the present application, the following further description is made in combination with the embodiments and the accompanying drawings.

[0032] Please refer to Figures 1 to 3The utility model provides a kind of plant fiber raw material drying tail gas's waste heat recovery device 100, including heat carrier storage tank 10, tail gas heat exchange tower 20 and air heat exchange tower 30. Heat carrier storage tank 10 includes first outlet 12 and first inlet 11, first outlet 12 is used to supply heat carrier to flow out, first inlet 11 is used to supply heat carrier to flow in, first outlet 12 is arranged at one end of heat carrier storage tank 10, and first inlet 11 is arranged at the other end of heat carrier storage tank 10. In addition, tail gas heat exchange tower 20 includes tail gas outlet 23, first gas-liquid separator 22, second inlet 21, first cloth liquid distributor 24, first packing zone 25, tail gas inlet 26, clarification section 28, second outlet 29 and condensate outlet 210 sequentially arranged from top to bottom. Specifically, cold heat carrier flows into tail gas heat exchange tower 20 by second inlet 21 and flows through first cloth liquid distributor 24, and first cloth liquid distributor 24 evenly distributes the cold heat carrier entering tail gas heat exchange tower 20 at the top of packing 201, so as to heat exchange with hot tail gas. Hot tail gas enters tail gas heat exchange tower 20 by tail gas inlet 26 and directly exchanges with cold heat carrier, so that hot tail gas becomes cold tail gas and passes through first gas-liquid separator 22 upwards. The liquid in cold tail gas is collected by first gas-liquid separator 22 and then flows back to first cloth liquid distributor 24, and cold tail gas is discharged from tail gas heat exchange tower 20 from tail gas outlet 23. And cold heat carrier becomes hot heat carrier after heat exchange, and hot heat carrier falls from first packing zone 25 into one side of clarification section 28 and realizes oil-water separation, and hot heat carrier is collected to flow out from second outlet 29, and condensate is discharged from condensate outlet 210. On the other hand, air heat exchange tower 30 includes hot air outlet 33, second gas-liquid separator 32, third inlet 31, second cloth liquid distributor 34, second packing zone 35, cold air inlet 36 and third outlet 37 sequentially arranged from top to bottom. Among them, third inlet 31 is communicated with second outlet 29, third outlet 37 is communicated with first inlet 11 or second inlet 21, and first outlet 12 or third outlet 37 is communicated with second inlet 21. Specifically, hot heat carrier flows into air heat exchange tower 30 by third inlet 31, and enters second cloth liquid distributor 34, and second cloth liquid distributor 34 evenly distributes the hot heat carrier entering air heat exchange tower 30 at the top of packing 201, so as to heat exchange with cold air. Cold air enters air heat exchange tower 30 by cold air inlet 36 and directly exchanges with hot heat carrier flowing downwards, and cold air becomes hot air and passes through second gas-liquid separator 32, and the liquid in hot air is collected by second gas-liquid separator 32 and then flows back to second cloth liquid distributor 34. Hot air is discharged from hot air outlet 33, and hot heat carrier becomes cold heat carrier after heat exchange and is discharged from third outlet 37.

[0033] Compared with the prior art, the plant fiber raw material drying tail gas waste heat recovery device 100, including heat carrying agent storage tank 10, tail gas heat exchange tower 20 and air heat exchange tower 30, heat carrying agent storage tank 10 is used for storing heat carrying agent, tail gas heat exchange tower 20 is used for heat tail gas and cold heat carrying agent heat exchange, air heat exchange tower 30 is used for hot heat carrying agent and cold air heat exchange.In the heat exchange process, tail gas heat exchange tower 20 and air heat exchange tower 30 are connected with each other, and the continuous working state of two towers is formed, the continuous heat exchange of hot tail gas and cold air is realized, and the waste heat recovery of drying tail gas is realized.Cold heat carrying agent flows into tail gas heat exchange tower 20 through second inlet 21 and flows through first liquid distributor 24, and first liquid distributor 24 is used to uniformly distribute cold heat carrying agent on the top of filler 201.Heat tail gas enters tail gas heat exchange tower 20 through tail gas inlet 26 and directly exchanges heat with cold heat carrying agent, so that hot tail gas becomes cold tail gas and passes through first gas-liquid separator 22 upwards.The liquid in the cold tail gas is collected by first gas-liquid separator 22 and then flows back to first liquid distributor 24, and the cold tail gas is discharged from tail gas heat exchange tower 20 through tail gas outlet 23.Cold heat carrying agent becomes hot heat carrying agent after heat exchange, and hot heat carrying agent falls from first filler area 25, flows into one side of clarification section 28 and realizes oil-water separation, and hot heat carrying agent is collected to second outlet 29 and flows out, and condensed water is discharged through condensed water outlet 210.In addition, the hot heat carrying agent flowing out from second outlet 29 flows into air heat exchange tower 30 through third inlet 31 and enters second liquid distributor 34, and second liquid distributor 34 is used to uniformly distribute hot heat carrying agent on the top of filler 201.Cold air enters air heat exchange tower 30 through cold air inlet 36 and directly exchanges heat with downward flowing hot heat carrying agent, and cold air becomes hot air and passes through second gas-liquid separator 32.The liquid in the hot air is collected by second gas-liquid separator 32 and then flows back to second liquid distributor 34, and the hot air is discharged through hot air outlet 33, and the hot heat carrying agent becomes cold heat carrying agent after heat exchange and is discharged from third outlet 37 and flows into tail gas heat exchange tower 20 from second inlet 21, and circulates repeatedly.The plant fiber raw material drying tail gas waste heat recovery device 100 of the utility model, through the direct heat exchange of heat carrying agent and drying tail gas and air, greatly improves the heat exchange efficiency, reduces the equipment investment, compared with the traditional waste heat recovery of drying tail gas through indirect heat exchange, the plant fiber raw material drying tail gas waste heat recovery device 100 of the utility model, the waste heat recovery of drying tail gas is convenient and the waste heat recovery efficiency is high.

[0034] Please refer to Figure 1In some alternative embodiments, the third outlet 37 of the air heat exchange tower 30 is connected to the second inlet 21 of the tail gas heat exchange tower 20 by a first pipe 41. A first circulating pump 40 is arranged on the first pipe 41, and the first circulating pump 40 is used to transfer the cold heat carrier from the third outlet 37 to the first inlet 11 or the second inlet 21. In one implementation, when the tail gas heat exchange tower 20 and the air heat exchange tower 30 are continuously heat exchanged, sufficient heat carrier flows into the tail gas heat exchange tower 20 from the heat carrier storage tank 10, and then the first valve 111 on the first inlet 11 of the heat carrier storage tank 10 can be closed, and the second valve 121 on the first outlet 12 can be closed. The heat carrier from the third outlet 37 of the air heat exchange tower 30 directly enters the tail gas heat exchange tower 20 through the second inlet 21, and the tail gas heat exchange tower 20 and the air heat exchange tower 30 are connected to each other and form a continuous working state of the two towers, so as to realize the continuous heat exchange between the hot tail gas and the cold air, thereby realizing the waste heat recovery of the drying tail gas. In another implementation, when the tail gas heat exchange is completed, the heat carrier can be recovered into the heat carrier storage tank 10, at this time, the second inlet 21 is closed, so that the cold heat carrier flows back to the heat carrier storage tank 10. The first outlet 12 is connected to a discharge pipe 42, the discharge pipe 42 is connected to the first pipe 41 and connected to the input end of the first circulating pump 40, so that the heat carrier from the heat carrier storage tank 10 can be transferred to the second inlet 21 by the first circulating pump 40.

[0035] Referring to Figure 1 In some alternative embodiments, the second outlet 29 is connected to the third inlet 31 by a second pipe 51, and the second pipe 51 is provided with a second circulating pump 50. The second circulating pump 50 is used to transfer the hot heat carrier from the second outlet 29 to the third inlet 31. It can be understood that the hot heat carrier flowing out of the second outlet 29 of the tail gas heat exchange tower 20 flows through the second pipe 51, and the second circulating pump 50 makes the hot heat carrier flow to the third inlet 31 of the air heat exchange tower 30.

[0036] Referring to Figure 1 and Figure 2In some optional embodiments, a flow collector 27 is arranged between the first packing zone 25 and the clarification section 28, the flow collector 27 is arranged obliquely, and the heat-carrying agent falling from the first packing zone 25 is guided to one side of the clarification section 28 through the flow collector 27. The second outlet 29 is arranged on the side of the clarification section 28 away from the flow of the flow collector 27. The heat-carrying agent gradually flows from one side of the clarification section 28 to the second outlet 29, realizing oil-water separation, and the heat-carrying agent flows out of the second outlet 29, and the condensed water is discharged from the condensed water outlet 210, and the condensed water valve 2101 that can be opened and closed is arranged on the condensed water outlet 210. Specifically, a plurality of porous plates 281 are arranged vertically in the clarification section 28, the porous plates 281 can well separate oil and water, thereby well separating the condensed water and the heat-carrying agent, and the plate surface of the porous plate 281 is perpendicular to the second outlet 29. The heat-carrying agent is an oil substance, which can be a mineral heat-conducting oil. The heat-conducting oil is usually made of a mixture of long-chain alkanes and cycloalkanes, has good thermal stability and high heat transfer efficiency, and has an upper limit temperature of generally 300°C, and is suitable for various conventional industrial heating and cooling applications. In addition, the oil substance can also be a synthetic heat-conducting oil, such as hydrogenated terphenyl heat-conducting oil. The upper limit temperature of this type of heat-conducting oil can reach 350°C, and also has excellent thermal stability and heat transfer efficiency, and is particularly suitable for applications that need to operate at a higher temperature. In actual production, the type of heat-conducting oil can be selected according to the actual temperature requirement of the drying tail gas.

[0037] Referring to Figures 1 to 3 In some optional embodiments, the first packing zone 25 and the second packing zone 35 are both filled with fillers 201. The fillers 201 are made of plastic material, or the fillers 201 are made of ceramic material. The plastic fillers 201 are preferably polypropylene fillers 201. On the other hand, the first gas-liquid separator 22 and the second gas-liquid separator 32 are used to capture and recover the heat-carrying agent carried by the gas out of the fillers 201. The fillers 201 in the first gas-liquid separator 22 and the second gas-liquid separator 32 can be PP hollow sphere fillers 201, or wire mesh fillers 201, and the wire mesh fillers 201 can be glass fiber mesh.

[0038] Referring to Figures 1 to 3 In some optional embodiments, the first liquid distributor 24 and the second liquid distributor 34 are used to uniformly distribute the heat-carrying agent on the top of the corresponding fillers 201. The first liquid distributor 24 is arranged rotatably in the tail gas heat exchange tower 20, and the second liquid distributor 34 is arranged rotatably in the air heat exchange tower 30. Specifically, the first liquid distributor 24 and the second liquid distributor 34 each include a plurality of main pipes, each main pipe includes a plurality of branch pipes, and each branch pipe is uniformly provided with a plurality of small holes.

[0039] Referring to Figures 1 to 3In some optional embodiments, the first inlet 11 is provided with a first valve 111 which can be opened and closed, and the first inlet 11 is selectively opened and closed through the first valve 111. The first outlet 12 is provided with a second valve 121 which can be opened and closed, and the first outlet 12 is selectively opened and closed through the second valve 121. The second inlet 21 is provided with a third valve 211 which can be opened and closed, and the second inlet 21 is selectively opened and closed through the third valve 211. The second outlet 29 is provided with a fourth valve 291 which can be opened and closed, and the second outlet 29 is selectively opened and closed through the fourth valve 291. The third inlet 31 is provided with a fifth valve 311 which can be opened and closed, and the third inlet 31 is selectively opened and closed through the fifth valve 311. The third outlet 37 is provided with a sixth valve 371 which can be opened and closed, and the third outlet 37 is selectively opened and closed through the sixth valve 371.

[0040] As Figures 1 to 3As shown, the plant fiber raw material drying tail gas waste heat recovery device 100 of the utility model, including heat carrier storage tank 10, tail gas heat exchange tower 20 and air heat exchange tower 30. Heat carrier storage tank 10 is used to store heat carrier, and tail gas heat exchange tower 20 is used to heat tail gas and cold heat carrier heat exchange, and air heat exchange tower 30 is used to heat heat carrier and cold air heat exchange. In the heat exchange process, tail gas heat exchange tower 20 and air heat exchange tower 30 are connected with each other and form the continuous working state of two towers, realize the continuous heat exchange of hot tail gas and cold air, so as to realize the waste heat recovery of drying tail gas. Wherein, the cold heat carrier flows into tail gas heat exchange tower 20 by second inlet 21 and flows through first liquid distributor 24, and first liquid distributor 24 is used to uniformly distribute the cold heat carrier on the top of the filler 201. Hot tail gas enters tail gas heat exchange tower 20 by tail gas inlet 26 and directly exchanges with cold heat carrier, so that hot tail gas becomes cold tail gas and passes through first gas-liquid separator 22 upwards. The liquid in the cold tail gas is collected by first gas-liquid separator 22 and then flows back to first liquid distributor 24, and the cold tail gas is discharged from tail gas heat exchange tower 20 by tail gas outlet 23. The cold heat carrier becomes hot heat carrier after heat exchange, and the hot heat carrier falls from the first filler area 25 into one side of the clarification section 28 and realizes oil-water separation, and the hot heat carrier is collected to the second outlet 29 and flows out, and the condensed water is discharged by condensed water outlet 210. In addition, the hot heat carrier flowing out from the second outlet 29 flows into air heat exchange tower 30 by third inlet 31 and enters second liquid distributor 34, and second liquid distributor 34 is used to uniformly distribute the hot heat carrier on the top of the filler 201. Cold air enters air heat exchange tower 30 by cold air inlet 36 and directly exchanges with the downward flowing hot heat carrier, and the cold air becomes hot air and passes through second gas-liquid separator 32. The liquid in the hot air is collected by second gas-liquid separator 32 and then flows back to second liquid distributor 34, and the hot air is discharged by hot air outlet 33 for repeated use, and the hot heat carrier becomes cold heat carrier after heat exchange and is discharged from third outlet 37 and flows into tail gas heat exchange tower 20 from second inlet 21, and circulates back and forth. The plant fiber raw material drying tail gas waste heat recovery device 100 of the utility model directly exchanges the heat carrier with drying tail gas and air, greatly improves the heat exchange efficiency, reduces the equipment investment, compared with the traditional waste heat recovery of drying tail gas through indirect heat exchange, the plant fiber raw material drying tail gas waste heat recovery device 100 of the utility model recovers the waste heat of drying tail gas conveniently and has high waste heat recovery efficiency.

[0041] The above disclosed is only the preferred embodiment of the utility model, and cannot be used to limit the scope of the utility model right, so the equivalent change made according to the utility model right claim all belong to the range covered by the utility model.

Claims

1. A plant fiber raw material drying exhaust gas waste heat recovery device characterized by comprising: a heat exchanger that exchanges heat between a raw material drying exhaust gas and a raw material drying exhaust gas; and a heat recovery unit that recovers waste heat of the raw material drying exhaust gas. The application relates to a heat exchange system for tail gas and air, which comprises the following parts: a heat carrier tank, which comprises a first outlet for the outflow of heat carrier and a first inlet for the inflow of heat carrier; a tail gas heat exchange tower, which comprises a tail gas outlet, a first gas-liquid separator, a second inlet, a first liquid distributor, a first packing zone, a tail gas inlet, a clarification section, a second outlet and a condensed water outlet arranged in sequence from top to bottom; cold heat carrier flows into the tail gas heat exchange tower through the second inlet and flows through the first liquid distributor, hot tail gas enters the tail gas heat exchange tower through the tail gas inlet and directly exchanges heat with the cold heat carrier, so that the hot tail gas becomes cold tail gas and passes through the first gas-liquid separator upwards, liquid in the cold tail gas is collected by the first gas-liquid separator and flows back to the first liquid distributor, and the cold heat carrier becomes hot heat carrier after completing heat exchange and flows into the clarification section from one side of the clarification section and realizes oil-water separation, the hot heat carrier flows out of the second outlet, and condensed water is discharged through the condensed water outlet; an air heat exchange tower, which comprises a hot air outlet, a second gas-liquid separator, a third inlet, a second liquid distributor, a second packing zone, a cold air inlet and a third outlet arranged in sequence from top to bottom; the third inlet is communicated with the second outlet, the third outlet is communicated with the first inlet or the second inlet, and the first outlet or the third outlet is communicated with the second inlet; the hot heat carrier flows into the air heat exchange tower through the third inlet and enters the second liquid distributor, the cold air enters the air heat exchange tower through the cold air inlet and directly exchanges heat with the downward flowing hot heat carrier, the cold air becomes hot air and passes through the second gas-liquid separator, liquid in the hot air is collected by the second gas-liquid separator and flows back to the second liquid distributor, the hot air is discharged through the hot air outlet, and the hot heat carrier becomes the cold heat carrier after completing heat exchange and is discharged from the third outlet. The third outlet and the second inlet are connected through a first pipeline, and a first circulating pump is arranged on the first pipeline and used for conveying the cold heat carrier from the third outlet to the first inlet or the second inlet.

2. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 1, characterized by, The first outlet is connected with a discharge pipeline, the discharge pipeline is connected with the first pipeline and connected with the input end of the first circulating pump.

3. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 2, characterized by, The second outlet and the third inlet are connected through a second pipeline, and a second circulating pump is arranged on the second pipeline and used for conveying the hot heat carrier from the second outlet to the third inlet.

4. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 1, characterized by, A flow collecting plate is arranged between the first packing zone and the clarification section, the hot heat carrier falling from the first packing zone is guided to one side of the clarification section through the flow collecting plate, and the second outlet is arranged on the side of the clarification section away from the flow collecting plate.

5. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 1, characterized by, A plurality of vertical porous plates are arranged in the clarification section, and the plate surfaces of the porous plates are perpendicular to the second outlet.

6. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 1, characterized by, ​ 7. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 1, characterized by, The first packing area and the second packing area are filled with packing, and the first liquid distributor and the second liquid distributor are used for uniformly distributing the heat carrier on the top of the corresponding packing.

8. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 7, characterized by, The first liquid distributor is rotatably arranged in the tail gas heat exchange tower, and the second liquid distributor is rotatably arranged in the air heat exchange tower. The first liquid distributor and the second liquid distributor each include a plurality of dry pipes, each of which includes a plurality of branch pipes, and each of the branch pipes is uniformly provided with a plurality of small holes.

9. The plant fiber feedstock drying tail gas waste heat recovery device according to claim 7, characterized by, The packing is made of plastic material, or the packing is made of ceramic material.

10. The plant fiber raw material drying exhaust gas waste heat recovery device according to claim 1, characterized by, The first inlet is provided with a first valve capable of being opened and closed, the first outlet is provided with a second valve capable of being opened and closed, the second inlet is provided with a third valve capable of being opened and closed, the second outlet is provided with a fourth valve capable of being opened and closed, the third inlet is provided with a fifth valve capable of being opened and closed, and the third outlet is provided with a sixth valve capable of being opened and closed.

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