CN108753337B

CN108753337B - Reaction system and method for preparing bio-oil by hydrothermal liquefaction of wet biomass

Info

Publication number: CN108753337B
Application number: CN201810630691.1A
Authority: CN
Inventors: 徐东海; 柳亮; 郭树炜; 汪洋; 郭洋; 景泽峰
Original assignee: Xian Jiaotong University
Current assignee: Xian Jiaotong University
Priority date: 2018-06-19
Filing date: 2018-06-19
Publication date: 2020-07-28
Anticipated expiration: 2038-06-19
Also published as: CN108753337A

Abstract

The invention discloses a reaction system and a method for preparing bio-oil by hydrothermal liquefaction of wet biomass, which comprises a catalytic reactor, wherein the catalytic reactor comprises a catalyst bottle, a primary reactor and a secondary reactor, an outlet of the catalyst bottle is divided into two paths, one path is connected with an inlet of the primary reactor through a pipeline with a primary wedge valve, the other path is connected with an outlet of the primary reactor through a pipeline with a secondary wedge valve, and an outlet of the primary reactor is connected with an inlet of the secondary reactor. The method comprises the following main operation steps: the wet biomass raw material is crushed and then enters a first-stage preheater for preheating, the preheated raw material is mixed with a catalyst added in a grading way, two-stage hydrothermal liquefaction reaction is carried out successively, and the high-pressure and high-temperature fluid after the reaction is subjected to multi-phase separation to respectively obtain gas phase, water phase, oil phase products and residues. The system has simple operation, thorough product separation and complete reaction, and can be widely applied to the production of bio-oil by hydrothermal liquefaction of wet biomass.

Description

Reaction system and method for preparing bio-oil by hydrothermal liquefaction of wet biomass

Technical Field

The invention belongs to the technical field of preparation of bio-oil, and particularly relates to a reaction system and a method for preparing bio-oil by hydrothermal liquefaction of wet biomass.

Background

With the rapid development of economy and the improvement of living standard of people's substances, the demand of energy is getting larger in the current environment, however, the conventional fossil energy is faced with the increasing exhaustion of resources and a series of environmental problems such as greenhouse effect caused by combustion, so that the search for clean and efficient green alternative energy is attracting the attention of society.

Biomass energy as a novel renewable energy source can be converted into liquid biomass oil through reaction processes such as pyrolysis, thermochemical reaction and gasification, and the closed cycle of carbon can be realized by utilizing the processes, thereby reducing CO₂The emission of the energy-saving device reduces the greenhouse effect, and greatly improves the high-efficiency utilization and the shortage of energy. The biomass contains protein, unsaturated fatty acid and other bioactive substances, has high biomass utilization efficiency and oil production efficiency, can grow in extreme environment, and is suitable for heavy goldThe ion has good adsorption effect and decomposition effect, and has wide development prospect and use prospect when being used as a subsequent reserve fuel.

The hydrothermal liquefaction technology is a process of converting raw material macromolecules of raw materials into biological crude oil, biological gas and biological carbon through a series of chemical reactions (including hydrolysis, bond breaking, aromatization, dehydration, deoxygenation and the like) under the subcritical/supercritical condition of water. The wet biomass hydrothermal liquefaction technology is an oil preparation technology with development prospect and has many advantages: firstly, wet biomass is used as a hydrothermal liquefaction reaction medium, and a drying process required by other technologies (such as pyrolysis and gasification reaction) is avoided, so that the reaction energy consumption is reduced. Secondly, the hydrothermal liquefaction technology of the wet biomass can convert the grease in the wet biomass into the bio-oil, and can convert substances such as protein, saccharides and the like in the wet biomass into the high-density bio-oil to the maximum extent. Meanwhile, in the hydrothermal liquefaction reaction process, when the phase change of water occurs, the enthalpy value is greatly reduced under high pressure, so that the potential energy loss in the process is reduced, and the hydrothermal liquefaction energy efficiency is improved.

Aiming at the research of the hydrothermal liquefaction technology of wet biomass, most of the hydrothermal liquefaction technology is single-stage catalytic liquefaction or liquefaction reaction is carried out in a single reaction container, and the problems of high system energy consumption, inconvenient product separation, low oil yield and the like of the existing reaction device generally exist.

At present, no reaction device for preparing bio-oil by hydrothermal liquefaction of wet biomass can effectively solve the problems. In view of the above-mentioned problems, the development and large-scale industrial utilization of hydrothermal liquefaction of wet biomass have been restricted, and therefore, new reaction apparatuses are continuously being developed.

Disclosure of Invention

The invention aims to provide a reaction system and a method for preparing bio-oil by hydrothermal liquefaction of wet biomass, and aims to solve the problems of high overall energy consumption, low quality and yield of bio-oil and unchanged product separation of a system for preparing bio-oil by hydrothermal liquefaction of wet biomass.

In order to achieve the purpose, the invention adopts the following technical scheme:

a reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass comprises a catalytic reactor, wherein the catalytic reactor comprises a catalyst bottle, a primary reactor and a secondary reactor, an outlet of the catalyst bottle is divided into two paths, one path is connected with an inlet of the primary reactor through a pipeline with a primary wedge valve, the other path is connected with an outlet of the primary reactor through a pipeline with a secondary wedge valve, and an outlet of the primary reactor is connected with an inlet of the secondary reactor.

Furthermore, a reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass further comprises a pulverizer, a storage box and a primary preheater, wherein an outlet of the pulverizer is connected with an inlet at the upper part of the storage box, an outlet at the bottom of the storage box is connected with a pipe side inlet of the primary preheater through a pipeline, a high-pressure pump is arranged on the pipeline, and the pipe side outlet of the primary preheater is connected with an inlet of the primary reactor.

Furthermore, a frequency converter is arranged on the high-pressure pump.

Furthermore, the outlet of the primary reactor is connected with the inlet of the tube side of the secondary preheater, and the outlet of the tube side of the secondary preheater is connected with the inlet of the secondary reactor.

Furthermore, the outlet of the secondary reactor is connected with the inlet of the shell side of the secondary preheater, and the outlet of the shell side of the secondary preheater is connected with the inlet of the multiphase separator.

Further, the upper part of the multiphase separator is provided with a gas outlet, the middle part of the multiphase separator is provided with a fluid outlet, the bottom of the multiphase separator is provided with a residue outlet, and the upper gas outlet is sequentially connected with a second supercharger, a first cooler, a dryer and a gas storage tank through pipelines; the middle fluid outlet is connected with the inlet of the centrifugal machine, and the outlet of the centrifugal machine is connected with the second cooler; the second cooler is provided with a water phase outlet and an oil phase outlet, the separated water phase is stored in the liquid storage tank through the water phase outlet, and the separated oil phase is stored in the oil storage tank through the oil phase outlet; the bottom residue outlet is connected with the residue storage tank through a pipeline.

The invention also provides a reaction method for preparing bio-oil by hydrothermal liquefaction of wet biomass, which comprises the following steps:

(1) putting the wet biomass raw material into a pulverizer for pulverizing treatment and then conveying the pulverized raw material into a storage tank;

(2) conveying the material prepared in the step (1) to a preheater for preheating through a high-pressure pump through a pipeline;

(3) the material is preheated in the first stage, mixed with the catalyst passing through the first stage wedge valve, conveyed to the first stage reactor for continuous heating and reaction, and the dosage of the catalyst participating in the reaction is determined by controlling the first stage wedge valve;

(4) mixing the product reacted in the step (3) with a catalyst passing through a secondary wedge valve, and then conveying the mixture to a secondary preheater for preheating, and determining the amount of the catalyst participating in the reaction by controlling the secondary wedge valve;

(5) conveying the preheated mixture to a secondary reactor, and continuously heating to the reaction temperature for hydrothermal liquefaction reaction;

(6) high-temperature high-pressure fluid obtained from a product generated by the second-stage hydrothermal liquefaction reaction is depressurized by a back pressure valve and then is conveyed to a multi-phase separator for multi-phase separation;

(7) the separated gas phase is pressurized by a second booster, cooled, dehydrated and dried, and finally stored in a gas storage tank; and separating the separated solid-phase residue in a residue storage tank, and separating the separated liquid phase into a water phase and an oil phase by a centrifugal machine, wherein the oil phase is stored in an oil storage tank, and the water phase is stored in a liquid storage tank after being cooled.

Further, the temperature of the multi-phase separator in the step (6) is controlled below the saturation temperature of water, so that the water is not mixed into the gas phase in the form of steam.

Compared with the prior art, the invention has at least the following beneficial effects:

1. the first-stage reactor can provide a primary hydrothermal liquefaction reaction environment for wet biomass materials, and the second-stage reactor can ensure the complete reaction of reactants by further heating the materials; the two-stage reactor can reduce the overall energy consumption of the reaction system and improve the oil yield.

2. Two-step catalytic liquefaction, through two pipelines, two wedge valves control the dosage of catalyst that gets into reaction system respectively, improve reaction rate, shorten whole reaction time, improve bio-oil quality.

3. The comprehensive use of the multiphase separator and the centrifuge can rapidly separate the liquefied product by simple steps, avoid the extraction process of the organic solvent, have simple operation and thorough product separation, and reduce the cost of the corresponding device.

Compared with other hydrothermal liquefaction systems, the system provided by the invention is simple to operate, thorough in product separation and complete in reaction, and can be widely applied to production of bio-oil by hydrothermal liquefaction of wet biomass.

Drawings

FIG. 1 is a schematic structural diagram of a reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass.

In the figure: 1. a material storage box; 2. a pulverizer; 3. a high pressure pump; 4. a primary preheater; 5. a secondary wedge valve; 6. a primary wedge valve; 7. a first stage reactor; 8. a secondary preheater; 9. a secondary reactor; 10. a second supercharger; 11. a first cooler; 12. a dryer; 13. a gas storage tank; 14. an oil storage tank; 15. a liquid storage tank; 16. a slag storage tank; 17. a second cooler; 18. a centrifuge; 19. a multi-phase separator; 20. a back pressure valve; 21. a catalyst bottle; 22. a first supercharger.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1, the present invention provides a reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass, including a catalytic reactor, a preheater, a multiphase separator, various material conveying pipelines and pipeline equipment, and having the following specific structure:

the outlet of the pulverizer 2 is connected with the inlet at the upper part of the storage box 1, the outlet at the bottom of the storage box 1 is connected with a high-pressure pump 3, the outlet of the high-pressure pump 3 is connected with the inlet position at the pipe side of a primary preheater 4, and the outlet at the pipe side of the primary preheater 4 is connected with the inlet of a primary reactor 7; the outlet of the catalyst bottle 21 is connected with the inlet of a first booster 22, the outlet of the first booster 22 is divided into two paths, one path is connected with the inlet of a first-stage reactor 7 through a pipeline with a first-stage wedge valve 6, and the other path is connected with the outlet of the first-stage reactor 7 through a pipeline with a second-stage wedge valve 5;

the outlet of the primary reactor 7 is connected with the inlet of the tube side of the secondary preheater 8, and the outlet of the tube side of the secondary preheater 8 is connected with the inlet of the secondary reactor 9;

the outlet of the secondary reactor 9 is connected with the shell-side inlet of the secondary preheater 8, and the shell-side outlet of the secondary preheater 8 is connected with the inlet of the multiphase separator 19; the upper part of the multiphase separator 19 is provided with a gas outlet, the middle part is provided with a fluid outlet, and the bottom part is provided with a residue outlet; the upper gas outlet is connected with a second supercharger 10, a first cooler 11, a dryer 12 and a gas storage tank 13 in sequence through pipelines; the middle fluid outlet is connected with the inlet of a centrifuge 18, and the outlet of the centrifuge 18 is connected with a second cooler 17; the second cooler 17 is provided with a water phase outlet and an oil phase outlet, the separated water phase is stored in the liquid storage tank 15 through the water phase outlet, and the separated oil phase is stored in the oil storage tank 14 through the oil phase outlet; the bottom residue outlet is connected with the residue storage tank 16 through a pipeline.

Referring to fig. 1, a reaction method for preparing bio-oil by hydrothermal liquefaction of wet biomass comprises the following steps:

(1) putting wet biomass raw materials into a pulverizer 2 for pulverization treatment and then conveying the pulverized raw materials into a storage tank 1;

(2) conveying the material prepared in the step (1) to a primary preheater 4 through a high-pressure pump 3 through a pipeline for preheating;

(3) the material is preheated in the first stage, mixed with the catalyst passing through the first stage wedge valve 6 and then conveyed to the first stage reactor 7 for continuous heating and reaction, and the dosage of the catalyst participating in the reaction is determined by controlling the first stage wedge valve 6;

(4) mixing the product reacted in the step (3) with a catalyst passing through a secondary wedge valve 5, then introducing the mixture into a secondary preheater 8 for preheating, and determining the catalyst dosage participating in the reaction by controlling the secondary wedge valve 5;

(5) the preheated mixture is conveyed to a secondary reactor 9 to be continuously heated to the reaction temperature for hydrothermal liquefaction reaction;

(6) high-temperature high-pressure fluid obtained from a product generated by the second-stage hydrothermal liquefaction reaction is depressurized by a back pressure valve 20 and then is introduced into a multiphase separator 19 for multiphase separation;

(7) the separated gas phase is pressurized by a second booster 10, cooled, dehydrated and dried, and finally stored in a gas storage tank 13; the separated solid-phase residue is in a residue storage tank 16, and the separated liquid phase is separated into a water phase and an oil phase by a centrifugal machine, wherein the oil phase is stored in the oil storage tank 14, and the water phase is stored in a liquid storage tank 15 after being cooled.

Claims

1. A reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass is characterized by comprising a catalytic reactor, wherein the catalytic reactor comprises a catalyst bottle (21), a first-stage reactor (7) and a second-stage reactor (9), an outlet of the catalyst bottle (21) is divided into two paths, one path is connected with an inlet of the first-stage reactor (7) through a pipeline with a first-stage wedge valve (6), the other path is connected with an outlet of the first-stage reactor (7) through a pipeline with a second-stage wedge valve (5), and an outlet of the first-stage reactor (7) is connected with an inlet of the second-stage reactor (9);

the hydrothermal liquefaction reaction is completed by a two-stage reactor, and the hydrothermal liquefaction reaction is connected to a multiphase separator (19) after reaction heat is collected by a preheater (8);

the wet biomass material is preheated in the first stage, mixed with the catalyst passing through the first-stage wedge valve (6), and then conveyed to the first-stage reactor (7) for continuous heating and reaction, and the dosage of the catalyst participating in the reaction can be determined by controlling the first-stage wedge valve (6);

the product after reaction in the first-stage reactor (7) is mixed with the catalyst passing through the second-stage wedge valve (5), then is preheated and enters the second-stage reactor (9), and the dosage of the catalyst participating in the reaction is determined by controlling the second-stage wedge valve (5);

the primary reactor provides a primary hydrothermal liquefaction reaction environment for wet biomass materials, and the secondary reactor can ensure the complete reaction of reactants by further heating the materials.

2. The reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass as claimed in claim 1, wherein the multiphase separator (19) is provided with a gas outlet at the upper part, a fluid outlet at the middle part and a residue outlet at the bottom; the upper gas outlet is connected with a second supercharger (10), a first cooler (11), a dryer (12) and a gas storage tank (13) in sequence through pipelines; the middle fluid outlet is connected with the inlet of a centrifuge (18), and the outlet of the centrifuge (18) is connected with a second cooler (17); the second cooler (17) is provided with a water phase outlet and an oil phase outlet, the separated water phase is stored in the liquid storage tank (15) through the water phase outlet, and the separated oil phase is stored in the oil storage tank (14) through the oil phase outlet; the bottom residue outlet is connected with a residue storage tank (16) through a pipeline.

3. A reaction method for preparing bio-oil by hydrothermal liquefaction of wet biomass is characterized in that the reaction system for preparing bio-oil by hydrothermal liquefaction of wet biomass based on claim 1 comprises the following steps:

(1) the wet biomass material is preheated in the first stage, mixed with the catalyst passing through the first-stage wedge valve (6), and then conveyed to the first-stage reactor (7) for continuous heating and reaction, and the dosage of the catalyst participating in the reaction is determined by controlling the first-stage wedge valve (6);

(2) mixing the product reacted in the step (1) with a catalyst passing through a secondary wedge valve (5), introducing the mixture into a secondary preheater (8) for preheating, and determining the amount of the catalyst participating in the reaction by controlling the secondary wedge valve (5);

(3) the preheated mixture is conveyed to a secondary reactor (9) to be continuously heated to the reaction temperature for hydrothermal liquefaction reaction;

(4) high-temperature high-pressure fluid obtained from a product generated by the second-stage hydrothermal liquefaction reaction is depressurized by a back pressure valve (20) and then is introduced into a multiphase separator (19) for multiphase separation;

(5) the separated gas phase is pressurized by a second booster (10), cooled, dehydrated and dried, and finally stored in a gas storage tank (13), the separated solid-phase residue is stored in a residue storage tank (16), the separated liquid phase is separated into a water phase and an oil phase by a centrifugal machine, wherein the oil phase is stored in a gas storage tank (14), and the water phase is stored in a liquid storage tank (15) after being cooled.