Biological fuel oil preparation system and method

Abstract

The invention relates to the technical field of bio-fuel oil, and discloses a bio-fuel oil preparation system and method.The bio-fuel oil preparation method comprises the steps that a biomass material and methyl alcohol are mixed for a liquefaction reaction, then crude bio-oil is obtained after filtration, centrifugation and fractionation treatment, and then the crude bio-oil is subjected to metal salt removal and filtration treatment to obtain the bio-fuel oil. The method has the advantages that the raw materials are combined with hydrogen to carry out hydrogenation reaction, and finally refined bio-oil is obtained through gas-liquid separation, so that the method is efficient and energy-saving, the recovery of products is simpler, and meanwhile, the recovery of solid residues and the recovery and reuse of methanol can be realized; biomass materials and methanol are rapidly heated and uniformly heated in a microwave liquefaction reactor, at the moment, methanol can reach a supercritical state, and biomass energy can be promoted to be deeply liquefied into crude oil; the biological crude oil and hydrogen are subjected to hydrogenation reaction in the microwave hydrogenation reactor, the biological crude oil to be subjected to hydrogenation reaction is promoted to be heated and is in contact with hydrogen for hydrogenation to generate refined biological oil, the reaction is rapid, and the reaction depth is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of biofuel oil, and in particular to a biofuel oil preparation system and method. Background Art

[0002] The existing biomass thermochemical processing technology for producing biofuel oil mainly uses biomass pyrolysis technology, which heats the biomass raw materials to about 500°C in an inert gas environment, volatile components escape, and the macromolecules in them break into small molecules and then condense to form bio-oil. H 2 , CH 4 ,CO,CO 2 Pyrolysis gas and coke byproducts. However, direct pyrolysis has high energy consumption. Now, microwave heating has become popular to drive the reaction. Microwaves have the advantages of fast heating, wide radiation area, and uniform heating. However, whether it is microwave pyrolysis or direct pyrolysis, the bio-oil produced by biomass pyrolysis technology has the disadvantages of high acidity, high water content, high oxygen content, and high viscosity. In addition, coke byproducts will be generated to poison the catalyst and hinder the reaction. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a biofuel oil which can efficiently and energy-savingly convert biomass into liquid biofuel oil, and can prepare and refine the biofuel oil.

[0004] In order to solve the above technical problems, the present invention provides a biofuel oil preparation system, comprising a crusher, a grinder, a microwave reactor, a gas storage tank, a first filter, a centrifuge, a fractionating tower, an electric refining cell, a microwave hydrogenation reactor, a hydrogen storage tank, a gas-liquid separator, a waste gas tank and a storage tank, wherein the discharge port of the crusher is connected to the feed port of the grinder, the discharge port of the grinder is connected to the feed port of the microwave reactor, the discharge port of the microwave reactor is connected to the feed port of the first filter, and the first discharge port of the first filter is connected to the feed port of the centrifuge. The liquid discharge port of the centrifuge is connected to the feed port of the fractionation tower, the discharge port of the fractionation tower is connected to the feed port of the electric refining cell, the discharge port of the electric refining cell is connected to the feed port of the second filter, the discharge port of the second filter is connected to the feed port of the microwave hydrogenation reactor, the gas inlet of the microwave hydrogenation reactor is connected to the hydrogen storage tank, the discharge port of the microwave hydrogenation reactor is connected to the feed port of the gas-liquid separator, the gas discharge port of the gas-liquid separator is connected to the waste gas tank, and the liquid discharge port of the gas-liquid separator is connected to the storage tank.

[0005] As a preferred embodiment of the present invention, the system further comprises a first distillation tower, a first waste liquid tank, a second distillation tower, a second waste liquid tank and a delivery pump, the distillation outlet of the distillation tower is connected to the feed port of the first distillation tower, the distillation outlet of the first distillation tower is connected to the first waste liquid tank, the discharge port of the first distillation tower is connected to the feed port of the second distillation tower, the distillation outlet of the second distillation tower is connected to the second waste liquid tank, the discharge port of the second distillation tower is connected to the input end of the delivery pump, and a return port is provided at the bottom of the microwave reactor, and the return port is connected to the output end of the delivery pump.

[0006] As a preferred embodiment of the present invention, the system also includes a dryer and a press, the first filter is provided with a first sewage outlet for discharging the filtered and isolated substances, the centrifuge is provided with a second sewage outlet for discharging the separated solids, the first sewage outlet and the second sewage outlet are respectively connected to the feed port of the dryer, and the discharge port of the dryer is connected to the feed port of the press.

[0007] As a preferred embodiment of the present invention, the dryer includes a sealed cabin, a conveyor belt, a heat exchange tube and a fan. The conveyor belt is arranged in the sealed cabin and along the left and right directions of the sealed cabin. A first air inlet is provided on the front side of the sealed cabin. The position of the heat exchange tube corresponds to the position of the first air inlet. The position of the exhaust end of the fan corresponds to the position of the heat exchange tube. A discharge pipe is provided on the top of the sealed cabin.

[0008] As a preferred embodiment of the present invention, the system also includes a second heat exchanger, the distillation outlet of the distillation tower is connected to the input port of the first medium channel of the second heat exchanger, the output port of the first medium channel of the second heat exchanger is connected to the feed port of the first distillation tower, and the second medium channel of the second heat exchanger is connected to the heat exchange tube to form a circulation loop.

[0009] As a preferred embodiment of the present invention, the system further comprises a third heat exchanger, the discharge port of the microwave hydrogenation reactor is connected to the input port of the first medium channel of the third heat exchanger, the output port of the second medium channel of the third heat exchanger is connected to the feed port of the gas-liquid separator, and the second medium channel of the third heat exchanger is connected to the heat exchange tube to form a circulation loop.

[0010] As a preferred embodiment of the present invention, the system further comprises a first heat exchanger, the discharge of the microwave reactor is connected to the input port of the first medium channel of the first heat exchanger, the output port of the first medium channel of the first heat exchanger is connected to the feed port of the first filter, and the second medium channel of the first heat exchanger is connected to the reboiler of the distillation tower.

[0011] As a preferred embodiment of the present invention, the microwave reactor comprises a first outer shell and a first microwave emitting tube, a first reaction cavity is arranged in the first outer shell, the first microwave emitting tube is arranged in the first reaction cavity, a stirring paddle is arranged in the first microwave generating tube, and a feed port, a discharge port and an air outlet of the microwave reactor are respectively connected to the interior of the microwave generating tube.

[0012] As a preferred embodiment of the present invention, the microwave hydrogenation reactor includes a second outer shell and a second microwave emitting tube, the feed port of the microwave hydrogenation reactor is arranged at the top of the second outer shell, the discharge port of the microwave hydrogenation reactor is arranged at the bottom of the second outer shell, a second reaction chamber is arranged in the second outer shell, the bottom of the second reaction chamber is filled with a first porcelain ball layer, the microwave emitting tube is arranged on the first porcelain ball layer, and the microwave generating tube is filled with a second porcelain ball layer, a first silicon replenisher layer, a catalyst layer, a second silicon replenisher layer and a third porcelain ball layer from top to bottom.

[0013] In addition, the present invention also provides a method for preparing biofuel oil, comprising the following steps:

[0014] S1: crushing and grinding the biomass material into particles and then mixing with methanol for liquefaction reaction;

[0015] S2: filtering the product after the liquefaction reaction and then centrifuging it to obtain a liquid mixture;

[0016] S3: fractionating the mixed liquid to separate methanol and small molecules with a boiling point close to that of methanol in the mixed liquid to obtain crude bio-oil;

[0017] S4: removing metal salts from the crude bio-oil, filtering it, and mixing it with hydrogen for hydrogenation reaction;

[0018] S5: separating the gas and liquid of the product after the hydrogenation reaction to obtain refined bio-oil;

[0019] In S2, the solid residue separated by filtering and centrifuging is dried and then pressed to obtain solid particle fuel; in S3, the substance separated by fractionation is rectified to obtain pure methanol.

[0020] The embodiment of the present invention provides a biofuel oil preparation system and method. Compared with the prior art, the beneficial effects are as follows: the present invention mixes biomass material with methanol for liquefaction reaction, and then obtains crude bio-oil after filtering, centrifugation and fractionation treatment. Then, the crude bio-oil is treated with hydrogen for hydrogenation reaction after removing metal salt and filtering, and finally obtains refined bio-oil after gas-liquid separation. The system is efficient and energy-saving, and the product recovery can be simpler. At the same time, the recovery of solid residue and the recovery and reuse of methanol can be realized. The biomass material and methanol are heated quickly and evenly in a microwave liquefaction reactor. At this time, the methanol can reach a supercritical state, which promotes the deep liquefaction of biomass into crude oil. The crude bio-oil and hydrogen are hydrogenated in the microwave hydrogenation reactor, which promotes the heating of the crude bio-oil to be hydrogenated and contact with hydrogen to generate refined bio-oil. The reaction is rapid, which is conducive to increasing the depth of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a system schematic diagram of the present invention;

[0022] Figure 2 It is a structural schematic diagram of a microwave reaction kettle of the present invention;

[0023] Figure 3 It is a structural schematic diagram of the microwave hydrogenation reactor of the present invention;

[0024] Figure 4 It is a structural schematic diagram of the drying machine of the present invention;

[0025] In the figure, 1, crusher; 2, grinder; 3, microwave reactor; 301, first shell; 302, first microwave emitting tube; 303, stirring paddle; 4, gas storage tank; 5, first filter; 6, centrifuge; 7, fractionation tower; 8, electric refining cell; 81, second filter; 9, microwave hydrogenation reactor; 901, second shell; 902, second microwave emitting tube; 903, first porcelain ball layer; 904, second porcelain ball layer; 905, first silicon supplement layer; 906, catalyst layer; 907, second silicon supplement agent layer; 908, the third porcelain ball layer; 10, the hydrogen storage tank; 11, the gas-liquid separator; 12, the waste gas tank; 13, the storage tank; 14, the first distillation tower; 15, the first waste liquid tank; 16, the second distillation tower; 17, the second waste liquid tank; 18, the delivery pump; 19, the dryer; 191, the sealed cabin; 192, the conveyor belt; 193, the heat exchange tube; 194, the fan; 195, the discharge pipeline; 20, the press; 21, the first heat exchanger; 22, the second heat exchanger; 23, the third heat exchanger; 24, the boiler. DETAILED DESCRIPTION

[0026] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] like Figure 1-4 As shown, a biofuel oil preparation system according to a preferred embodiment of the present invention comprises a crusher 1, a grinder 2, a microwave reactor 3, a gas storage tank 4, a first filter 5, a centrifuge 6, a fractionating tower 7, an electric refining cell 8, a microwave hydrogenation reactor 9, a hydrogen storage tank 10, a gas-liquid separator 11, a waste gas tank 12 and a storage tank 13, the discharge port of the crusher 1 is connected to the feed port of the grinder 2, the discharge port of the grinder 2 is connected to the feed port of the microwave reactor 3, the discharge port of the microwave reactor 3 is connected to the feed port of the first filter 5, the first discharge port of the first filter 5 is connected to the feed port of the centrifuge 6 The feed port is connected, the liquid discharge port of the centrifuge 6 is connected to the feed port of the distillation tower 7, the discharge port of the distillation tower 7 is connected to the feed port of the electric refining cell 8, the discharge port of the electric refining cell 8 is connected to the feed port of the second filter 81, the discharge port of the second filter 81 is connected to the feed port of the microwave hydrogenation reactor 9, the air inlet of the microwave hydrogenation reactor 9 is connected to the hydrogen storage tank 10, the discharge port of the microwave hydrogenation reactor 9 is connected to the feed port of the gas-liquid separator 11, the gas discharge port of the gas-liquid separator 11 is connected to the waste gas tank 12, and the liquid discharge port of the gas-liquid separator 11 is connected to the storage tank 13.

[0028] The working principle of this embodiment is as follows: firstly, the biomass raw material (woody biomass containing cellulose, hemicellulose and lignin or seaweed biomass containing lipid and protein) is put into the crusher 1 for crushing into small particles, and then the crushed raw material is transported to the grinder 2 for grinding into particles with uniform shape; then the ground raw material is transported to the microwave reactor 3, and methanol and a catalyst are provided in the microwave reactor 3. The raw material is mixed with methanol under the action of the catalyst for liquefaction reaction. Methanol is used as a solvent. Under the action of microwaves, the temperature rises rapidly and is maintained at about 285°C, so that the methanol enters a supercritical state, which can accelerate the liquefaction reaction. The liquefaction reaction will generate gas (mainly CO, H 2 O,CO 2 and CH 4), which enters the gas storage tank 4 through the exhaust port of the microwave reactor 3, and the liquefied reaction product (liquid mixture with a temperature greater than 200°C and a small amount of unliquefied solid residue) remaining in the microwave reactor 3 is transported to the first filter 5 through the discharge port of the microwave reactor 3 for filtering treatment, and part of the solid residue and part of the heavy tar are filtered; then the filtered liquefied reaction product is transported to the centrifuge 6 for centrifugal treatment, wherein the solid residue is separated and removed to obtain a liquid mixture; then the liquid mixture is transported to the fractionation tower 7 for fractionation treatment, so as to separate the methanol and other small amounts of small molecular substances with similar boiling points (ether, formic acid, ethanol, acetic acid, etc.) in the liquid mixture. , and crude bio-oil is obtained; then the crude bio-oil is transported to the electric refining cell 8 to remove metal salts; the desalted crude bio-oil is then transported to the second filter 81 for filtration, and the filtration confirms that the oil does not contain particles and metal salts; then the filtered crude bio-oil is transported to the microwave hydrogenation reactor 9, and a catalyst is provided in the microwave hydrogenation reactor 9. The hydrogen storage tank 10 introduces hydrogen into the microwave hydrogenation reactor 9, and the crude bio-oil is mixed with hydrogen under the action of the catalyst to undergo a hydrogenation reaction; finally, the product of the hydrogenation reaction is transported to the gas-liquid separator 11, and the gas (hydrogen sulfide and ammonia) generated by the reaction is transported to the waste gas tank 12, and finally refined bio-oil is obtained and transported to the outlet storage tank 13 for storage.

[0029] The present invention does not adopt the technical route of biomass pyrolysis, but adopts biomass liquefaction, directly liquefying biomass solid particles into liquid, and the product recovery can be simpler; the biomass material and methanol are heated quickly and evenly in the microwave liquefaction reactor, and the methanol can reach a supercritical state at this time, which promotes the deep liquefaction of biomass into crude oil; the biological crude oil and hydrogen are hydrogenated in the microwave hydrogenation reactor 9, which promotes the biological crude oil to be hydrogenated to heat up and contact with hydrogen to generate refined bio-oil.

[0030] Exemplarily, the system further includes a first distillation tower 14, a first waste liquid tank 15, a second distillation tower 16, a second waste liquid tank 17 and a delivery pump 18. The distillation outlet of the distillation tower 7 is connected to the feed port of the first distillation tower 14, the distillation outlet of the first distillation tower 14 is connected to the first waste liquid tank 15, the discharge port of the first distillation tower 14 is connected to the feed port of the second distillation tower 16, the distillation outlet of the second distillation tower 16 is connected to the second waste liquid tank 17, the discharge port of the second distillation tower 16 is connected to the input end of the delivery pump 18, and a return port is provided at the bottom of the microwave reactor 3, which is connected to the output end of the delivery pump 18. When the liquid mixture is transported to the distillation tower 7 for fractionation treatment, methanol and other small molecules with similar boiling points (ether, formic acid, ethanol, acetic acid) in the liquid mixture are discharged. The products (such as ethanol, formic acid and acetic acid) with a boiling point higher than that of methanol are separated and transported to the second waste liquid tank 17 through the distillation outlet of the distillation tower 16. At this time, the remaining products in the second distillation tower 16 are pure methanol, which is transported to the return port of the microwave reactor 3 by a pumping pump to realize the recovery and utilization of methanol.

[0031] Exemplarily, the system also includes a dryer 19 and a press 20, the first filter 5 is provided with a first sewage outlet for discharging filtered and isolated substances, the centrifuge 6 is provided with a second sewage outlet for discharging separated solids, the first sewage outlet and the second sewage outlet are respectively connected to the feed port of the dryer 19, the discharge port of the dryer 19 is connected to the feed port of the press 20, and the solid residue separated by the first filter 5 and the centrifuge 6 is mainly solid residue, on which methanol and other liquids remain. The solid residue is transported to the dryer 19, dried to separate the methanol and other liquids on the solid residue, and finally transported to the press 20, which is pressed into a solid shaped particle fuel of about 3 cm in length, thereby realizing the recycling of the solid residue.

[0032] Exemplarily, the dryer includes a sealed cabin 191, a conveyor belt 192, a heat exchange tube 193 and a fan 194. The conveyor belt 192 is arranged in the sealed cabin 191 and is arranged along the left and right directions of the sealed cabin 191. In this embodiment, the conveying direction of the conveyor belt 192 is from the right side to the left side of the sealed cabin 191. The feed inlet of the dryer is arranged on the right side of the sealed cabin 191, and the discharge port of the dryer is arranged on the left side of the sealed cabin 191. The front side of the sealed cabin 191 is provided with a first air inlet, and the position of the heat exchange tube 193 corresponds to the position of the first air inlet. The fan 194 is provided with a heat exchange tube 193 and a heat exchange tube 193. The position of the exhaust end of 94 corresponds to the position of the heat exchange tube 193. A discharge pipe 195 is provided on the top of the sealed cabin 191. The solid residue is transported to the feed port of the dryer through the first sewage outlet and the second sewage outlet, and then transported to the conveyor belt 192. During the transportation of the conveyor belt 192, the outside air passes through the first air inlet, and then contacts with the heat exchange tube 193 to be heated. Then the fan 194 blows the heated air to the solid residue on the conveyor belt 192, and blows the methanol and other liquids on the solid residue to the discharge pipe 195 for discharge.

[0033] Exemplarily, the system also includes a second heat exchanger 22, the distillation outlet of the distillation tower 7 is connected to the input port of the first medium channel of the second heat exchanger 22, the output port of the first medium channel of the second heat exchanger 22 is connected to the feed port of the first distillation tower 14, and the second medium channel of the second heat exchanger 22 is connected to the heat exchange pipe 193 to form a circulation loop, that is, the material separated by distillation in the distillation process is transported through the distillation outlet of the distillation tower 7 through the first medium channel of the second heat exchanger 22, and then transported to the first distillation tower 14, and the second medium channel of the second heat exchanger 22 is connected to the heat exchange pipe 193, that is, the medium in the heat exchange pipe 193 of the material separated by distillation in the distillation process is heat exchanged to realize the utilization of waste heat.

[0034] Exemplarily, the system also includes a third heat exchanger 23, the discharge port of the microwave hydrogenation reactor 9 is connected to the input port of the first medium channel of the third heat exchanger, the output port of the second medium channel of the third heat exchanger 23 is connected to the feed port of the gas-liquid separator 11, and the second medium channel of the third heat exchanger 23 is connected to the heat exchange tube 193 to form a circulation loop, that is, the product after the hydrogenation reaction is transported through the first medium channel of the third heat exchanger 23 and then transported to the gas-liquid separator 11, and the second medium channel of the third heat exchanger 23 is connected to the heat exchange tube 193, that is, the product after the hydrogenation reaction is heat exchanged with the medium in the heat exchange tube 193, so as to realize the utilization of waste heat and effectively reduce energy consumption.

[0035] Exemplarily, the system also includes a first heat exchanger 21, the discharge of the microwave reactor 3 is connected to the input port of the first medium channel of the first heat exchanger 21, and the output port of the first medium channel of the first heat exchanger 21 is connected to the feed port of the first filter 5, that is, the product after the liquefaction reaction is transported through the first medium channel of the first heat exchanger 21, and then transported to the first filter 5, so as to realize the utilization of the waste heat of the product after the liquefaction reaction. In this embodiment, the distillation tower 7 is connected to a boiler 24, and the boiler 24 introduces steam into the reboiler at the bottom of the distillation tower 7 through a steam delivery pipeline, and the second medium channel of the first heat exchanger 21 is connected to the reboiler of the distillation tower 7, so as to realize the utilization of the waste heat of the product after the liquefaction reaction and effectively reduce energy consumption.

[0036] Exemplarily, the microwave reactor 3 includes a first shell 301 and a first microwave transmitting tube 302. A first reaction cavity is provided in the first shell 301. The first microwave transmitting tube 302 is provided in the first reaction cavity. A stirring paddle 303 is provided in the first microwave generating tube. The feed port, the discharge port and the gas outlet of the microwave reactor 3 are respectively connected to the interior of the microwave generating tube. The material of the first microwave transmitting tube 302 is mica sheet. The microwave reactor 3 is also provided with a controller to control the microwave radiation intensity, and then control the temperature and pressure. The microwave in the microwave reactor 3 is mainly heated by the first microwave transmitting tube 302, and has the advantages of fast heating, wide radiation surface and uniform heating.

[0037] Exemplarily, the microwave hydrogenation reactor 9 includes a second outer shell 901 and a second microwave transmitting tube 902. The feed port of the microwave hydrogenation reactor 9 is arranged at the top of the second outer shell 901, and the discharge port of the microwave hydrogenation reactor 9 is arranged at the bottom of the second outer shell 901. A second reaction chamber is arranged in the second outer shell 901. The microwave hydrogenation generator mainly realizes heating through the second microwave transmitting tube 902. The bottom of the second reaction chamber is filled with a first porcelain ball layer 903, and the microwave transmitting tube is arranged on the first porcelain ball layer 903. The microwave generating tube is filled with a second porcelain ball layer 904, a first silicon replenishing agent layer 905, a catalyst layer 906, a second silicon replenishing agent layer 907 and a third porcelain ball layer 908 from top to bottom, so as to increase the gas or liquid distribution points and support and protect the active catalyst with low strength.

[0038] In addition, the present invention also provides a method for preparing biofuel oil, comprising the following steps:

[0039] S1: crushing and grinding the biomass material into particles and then mixing with methanol for liquefaction reaction;

[0040] S2: filtering the product after the liquefaction reaction and then centrifuging it to obtain a liquid mixture;

[0041] S3: fractionating the mixed liquid to separate methanol and small molecules with a boiling point close to that of methanol in the mixed liquid to obtain crude bio-oil;

[0042] S4: removing metal salts from the crude bio-oil, filtering it, and mixing it with hydrogen for hydrogenation reaction;

[0043] S5: separating the gas and liquid of the product after the hydrogenation reaction to obtain refined bio-oil;

[0044] In S2, the solid residue separated by filtering and centrifuging is dried and then pressed to obtain solid particle fuel; in S3, the substance separated by fractionation is rectified to obtain pure methanol.

[0045] The method mixes biomass materials with methanol for liquefaction reaction, and then obtains crude bio-oil after filtering, centrifuging and fractionating. Then, the crude bio-oil is treated by removing metal salts and filtering, and then combined with hydrogen for hydrogenation reaction, and finally refined bio-oil is obtained after gas-liquid separation. The method is efficient and energy-saving, and the recovery of products is simpler. At the same time, the recovery of solid residues and the recovery and reuse of methanol can be realized.

[0046] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A biofuel oil preparation system, characterized in that: The invention comprises a crusher, a grinder, a microwave reactor, a gas storage tank, a first filter, a centrifuge, a fractionating tower, an electric refining cell, a microwave hydrogenation reactor, a hydrogen storage tank, a gas-liquid separator, a waste gas tank and a storage tank, wherein the discharge port of the crusher is connected to the feed port of the grinder, the discharge port of the grinder is connected to the feed port of the microwave reactor, the exhaust port of the microwave reactor is connected to the gas storage tank, the discharge port of the microwave reactor is connected to the feed port of the first filter, the first discharge port of the first filter is connected to the feed port of the centrifuge, and the centrifuge The liquid outlet is connected to the feed port of the fractionation tower, the outlet of the fractionation tower is connected to the feed port of the electric refining cell, the outlet of the electric refining cell is connected to the feed port of the second filter, the outlet of the second filter is connected to the feed port of the microwave hydrogenation reactor, the gas inlet of the microwave hydrogenation reactor is connected to the hydrogen storage tank, the outlet of the microwave hydrogenation reactor is connected to the feed port of the gas-liquid separator, the gas outlet of the gas-liquid separator is connected to the waste gas tank, and the liquid outlet of the gas-liquid separator is connected to the storage tank.

2. The biofuel oil preparation system according to claim 1, characterized in that: The invention also includes a first distillation tower, a first waste liquid tank, a second distillation tower, a second waste liquid tank and a delivery pump. The distillation outlet of the distillation tower is connected to the feed port of the first distillation tower, the distillation outlet of the first distillation tower is connected to the first waste liquid tank, the discharge port of the first distillation tower is connected to the feed port of the second distillation tower, the distillation outlet of the second distillation tower is connected to the second waste liquid tank, the discharge port of the second distillation tower is connected to the input end of the delivery pump, and a return port is provided at the bottom of the microwave reactor, and the return port is connected to the output end of the delivery pump.

3. The biofuel oil preparation system according to claim 2, characterized in that: It also includes a dryer and a press, the first filter is provided with a first drain port for discharging filtered and isolated substances, the centrifuge is provided with a second drain port for discharging separated solids, the first drain port and the second drain port are respectively connected to the feed port of the dryer, and the discharge port of the dryer is connected to the feed port of the press.

4. The biofuel oil preparation system according to claim 3, characterized in that: The dryer includes a sealed cabin, a conveyor belt, a heat exchange tube and a fan. The conveyor belt is arranged in the sealed cabin and along the left and right directions of the sealed cabin. A first air inlet is arranged on the front side of the sealed cabin. The position of the heat exchange tube corresponds to the position of the first air inlet. The position of the exhaust end of the fan corresponds to the position of the heat exchange tube. A discharge pipe is arranged on the top of the sealed cabin.

5. The biofuel oil preparation system according to claim 4, characterized in that: It also includes a second heat exchanger, the distillation outlet of the distillation tower is connected to the input port of the first medium channel of the second heat exchanger, the output port of the first medium channel of the second heat exchanger is connected to the feed port of the first distillation tower, and the second medium channel of the second heat exchanger is connected to the heat exchange pipe to form a circulation loop.

6. The biofuel oil preparation system according to claim 4, characterized in that: It also includes a third heat exchanger, the discharge port of the microwave hydrogenation reactor is connected to the input port of the first medium channel of the third heat exchanger, the output port of the second medium channel of the third heat exchanger is connected to the feed port of the gas-liquid separator, and the second medium channel of the third heat exchanger is connected to the heat exchange tube to form a circulation loop.

7. The biofuel oil preparation system according to claim 1, characterized in that: It also includes a first heat exchanger, the discharge of the microwave reactor is connected to the input port of the first medium channel of the first heat exchanger, the output port of the first medium channel of the first heat exchanger is connected to the feed port of the first filter, and the second medium channel of the first heat exchanger is connected to the reboiler of the distillation tower.

8. The biofuel oil preparation system according to claim 1, characterized in that: The microwave reactor comprises a first shell and a first microwave emitting tube. A first reaction cavity is arranged in the first shell. The first microwave emitting tube is arranged in the first reaction cavity. A stirring paddle is arranged in the first microwave generating tube. The feed port, the discharge port and the gas outlet of the microwave reactor are respectively connected to the interior of the microwave generating tube.

9. The biofuel oil preparation system according to claim 1, characterized in that: The microwave hydrogenation reactor comprises a second outer shell and a second microwave emitting tube. The feed port of the microwave hydrogenation reactor is arranged at the top of the second outer shell, and the discharge port of the microwave hydrogenation reactor is arranged at the bottom of the second outer shell. A second reaction chamber is arranged in the second outer shell, and a first porcelain ball layer is filled at the bottom of the second reaction chamber. The microwave emitting tube is arranged on the first porcelain ball layer, and the second porcelain ball layer, a first silicon replenishing agent layer, a catalyst layer, a second silicon replenishing agent layer and a third porcelain ball layer are filled in the microwave generating tube from top to bottom in sequence.

10. A method for preparing biofuel oil, characterized in that: The following steps are involved: S1: crushing and grinding the biomass material into particles and then mixing with methanol for liquefaction reaction; S2: filtering the product after the liquefaction reaction and then centrifuging it to obtain a liquid mixture; S3: fractionating the mixed liquid to separate methanol and small molecules with a boiling point close to that of methanol in the mixed liquid to obtain crude bio-oil; S4: removing metal salts from the crude bio-oil, filtering it, and mixing it with hydrogen for hydrogenation reaction; S5: separating the gas and liquid of the product after the hydrogenation reaction to obtain refined bio-oil; In S2, the solid residue separated by filtering and centrifuging is dried and then pressed to obtain solid particle fuel; in S3, the substance separated by fractionation is rectified to obtain pure methanol.

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