Novel post-treatment method for hydrothermal liquefaction reaction of biomass

Abstract

The invention belongs to the technical field of biomass hydrothermal liquefaction post-treatment, and particularly relates to a novel biomass hydrothermal liquefaction reaction post-treatment method which comprises the following steps: performing gas-liquid separation on a mixture after a biomass hydrothermal liquefaction reaction to obtain a gas-phase product and a primary liquid-phase product; the solid content is gt; carrying out solid-liquid pre-separation on 15% of the primary liquid-phase product to obtain a pre-separated solid-phase product and a secondary liquid-phase product of which the solid content is less than or equal to 5%; separating a mixture of the primary liquid-phase product with the solid content being less than or equal to 15% and the secondary liquid-phase product with the solid content being less than or equal to 5% through filtering equipment to obtain a filtered solid-phase product and a liquid-phase product with the solid content being less than or equal to 1%; extracting and separating a filtered solid-phase product; extracting the residual solid phase in the filtered liquid phase product with the solid content of less than or equal to 1% by using an organic solvent to obtain an organic phase and a water phase product with the solid content of less than or equal to 1%; and separating the organic phase to purify the bio-oil. The biomass hydrothermal liquefaction reaction post-treatment efficiency and the oil product separation effect are improved, and the separation cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass hydrothermal liquefaction post-treatment, and in particular relates to a new method for biomass hydrothermal liquefaction reaction post-treatment. Background Art

[0002] Biomass energy ranks fourth in the world's total energy consumption after coal, oil and natural gas, and plays an important role in the entire energy system. Biomass is renewable, abundant and carbon neutral, so it is favored by people.

[0003] Hydrothermal liquefaction technology is a type of biomass thermochemical conversion technology. Water is used as a solvent. At a certain temperature (200℃~370℃) and pressure (5MPa~22MPa), biomass is transformed into liquid organic small molecules through depolymerization, bond breaking, decarboxylation, etc. These unstable small molecules then repolymerize to form liquid products. The separated liquid fuel is called bio-oil.

[0004] Biomass hydrothermal liquefaction technology is an effective method for converting biomass raw materials such as pig manure, sludge, rice straw, lignin, etc. into liquid biomass oil fuel, and has a very broad application prospect. The existing post-treatment technologies for biomass hydrothermal liquefaction reactions mainly include: centrifugal separation, multi-stage membrane separation, rotary evaporation, purification and other steps. However, these technologies still have some problems: first, the solid-liquid separation effect of centrifugal separation is not good, resulting in a large amount of solid residues in the product; second, the use and maintenance costs of multi-stage membrane separation are high; third, traditional rotary evaporation to remove water solvents consumes a lot of electricity; fourth, secondary pollution is easily generated during the purification process, affecting the quality of the product; fifth, the treatment efficiency is low and cannot meet the needs of large-scale production; sixth, separation produces a large amount of wastewater, causing huge environmental pressure. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a new method for post-treatment of biomass hydrothermal liquefaction reaction, which comprehensively utilizes technologies such as gas-liquid separation, solid-liquid separation, oil-water separation, solvent separation and product purification to solve the problems of low efficiency, high cost and poor environmental protection of existing biomass hydrothermal liquefaction reaction post-treatment, improve the treatment efficiency and enhance the quality of post-treated biomass oil products.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A novel method for post-treatment of biomass hydrothermal liquefaction reaction comprises the following steps: Step (1), performing gas-liquid separation on the mixture obtained after the hydrothermal liquefaction reaction of the biomass by means of a gas-liquid separation kettle to obtain a gas phase product and a primary liquid phase product; The mixture is a biomass hydrothermal liquefied mixture having a solid content of 2.5% to 20% obtained by hydrothermal reaction of biomass and water at a temperature of 200° C. to 370° C. and a pressure of 5 MPa to 22 MPa; Step (2), firstly performing solid-liquid pre-separation on the primary liquid phase product having a solid content of more than 15% by a centrifugal separation device to obtain a pre-separated solid phase product and a secondary liquid phase product having a solid content of ≤5%; Then, a mixture of a primary liquid phase product having a solid content of ≤15% and a secondary liquid phase product having a solid content of ≤5% is separated by a filtering device to obtain a filtered solid phase product and a filtered liquid phase product having a solid content of ≤1%; Step (3), according to the total weight of the solid phase product after filtration, the separation efficiency and separation effect required in actual work, select appropriate extraction equipment for extraction, separation and enrichment; continuous extraction equipment can achieve continuous separation of products, usually with higher separation efficiency and better separation effect, and intermittent extraction equipment can perform multiple extraction and separation; According to the density of the residual solid phase in the filtered liquid product with a solid content of ≤1%, different organic solvents were selected for extraction to separate the organic phase and the aqueous phase product with a solid content of ≤1%, as follows: If the density of the residual solid phase is greater than that of water, an organic solvent with a density of <1 g / mL is selected to extract the liquid phase product after filtration; if the density of the residual solid phase is less than that of water, an organic solvent with a density of >1 g / mL is selected to extract the liquid phase product after filtration; Step (4), separating and purifying the solute from the organic phase by separation and purification equipment, the obtained solute is bio-oil, and the organic solvent is recovered and recycled for the previous extraction and separation step.

[0007] In a preferred example, in step (1), the biomass is selected from one or more of animal manure and kitchen waste, municipal industrial solid wastewater, and cellulose or wood cellulose materials.

[0008] In a preferred example, in step (2), the filtering device is one of a funnel, a filter press or a filter; and the filter cloth of the filtering device has a pore size of <1 mm.

[0009] In a preferred example, in step (3), the extraction equipment is an intermittent extraction equipment or a continuous extraction equipment, the intermittent extraction equipment is one of a separatory bottle or an extraction tank, and the continuous extraction equipment is one of an extraction machine or an extraction tower.

[0010] In a preferred example, in step (3), the organic solvent with a density <1 g / mL is ethyl acetate or diethyl ether, and the organic solvent with a density >1 g / mL is dichloromethane or tetrachloromethane.

[0011] In a preferred example, in step (3), the amount of organic solvent added is 5% to 100% by volume of the liquid phase product after filtration.

[0012] In a preferred example, in step (3), the aqueous phase product with a solid content of ≤1% is used as a solvent for the hydrothermal liquefaction reaction of biomass for the circulation reaction.

[0013] In a preferred example, in step (4), a solid desiccant is used to further separate and purify the bio-oil.

[0014] In a preferred example, in step (4), the separation and purification equipment is a rotary evaporator or a distillation tower.

[0015] In a preferred example, the gas-liquid separation kettle, filtering equipment, extraction equipment, and separation and purification equipment are respectively connected by pipelines for continuous separation.

[0016] In the post-treatment process of the biomass hydrothermal liquefaction reaction of the present invention, first, a gas-liquid separation kettle is used to separate the gas and liquid of the reaction product to obtain a liquid phase; secondly, a centrifugal separation device and a filtering device are used to achieve solid-liquid separation to obtain solid residues and liquids; then, the liquid is passed through an extraction device to achieve oil-water separation; wherein, according to the density and hydrophilic and hydrophobic characteristics of the material, different organic solvents are used for extraction so that some tiny solid particles enter the water phase for separation; if the material reaction is insufficient, the extracted water phase can be recycled for reaction and utilization to reduce wastewater discharge; finally, the oil phase is passed through a rotary evaporator or a distillation tower and other equipment to achieve solute biomass oil separation and purification, and the obtained organic solvent is recycled for the previous extraction and separation, and the oil product obtained by rotary evaporation or distillation can be further separated and purified by adding a solid desiccant to obtain high-quality liquid biomass oil fuel.

[0017] Compared with the prior art, the novel method for post-treatment of biomass hydrothermal liquefaction reaction of the present invention achieves high-efficiency, low-cost, environmentally friendly and quality-improving treatment effects by respectively optimizing and comprehensively utilizing the steps of gas-liquid separation, solid-liquid separation, oil-water separation, solvent separation and product purification, and has broad prospects for promotion and application. By implementing the method of the present invention, the efficiency of post-treatment of biomass hydrothermal liquefaction reaction and the quality of oil products can be significantly improved, the separation cost can be reduced, and strong support is provided for the sustainable development of biomass energy. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in conjunction with specific embodiments, but the present invention is not limited to these embodiments. It should be noted that, under the premise of not conflicting, the embodiments described below or the technical features can be arbitrarily combined to form new embodiments. In the present invention, unless otherwise specified, all parts and percentages are mass units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, if not otherwise specified, are conventional methods in the art.

[0019] As used herein, the terms "comprises," "including," "contains," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0020] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range limited by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether this range is disclosed separately. For example, when a range of "1 to 4" is disclosed, the described range should be interpreted as including a range of "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4", etc. When a numerical range is described in this article, unless otherwise stated, this range is intended to include its end values ​​and all integers and fractions within this range.

[0021] The specific embodiments of the present invention are described in detail below.

[0022] Example 1

[0023] A novel method for post-treatment of biomass hydrothermal liquefaction reaction comprises the following steps: Step (1), performing gas-liquid separation on the mixture obtained after the hydrothermal liquefaction reaction of the biomass by means of a gas-liquid separation kettle to obtain a gas phase product and a primary liquid phase product; The mixture is a biomass hydrothermal liquefied mixture having a solid content of 10% obtained by hydrothermal reaction of biomass and water at a temperature of 320° C. and a pressure of 18 MPa; The biomass is a mixture of municipal industrial solid wastewater and crop straw; Step (2), separating the primary liquid phase product with a solid content of ≤15% by a filter press to obtain a filtered solid phase product and a filtered liquid phase product with a solid content of ≤1%; The filter cloth of the filter press has a pore size of 0.1 mm; Step (3), selecting a suitable extraction tank for intermittent extraction separation and enrichment according to the total weight of the solid phase product after filtration, the separation efficiency and separation effect required in actual work; According to the density of the residual solid phase in the filtered liquid product with a solid content of ≤1%, in this embodiment, an organic solvent-ether with a density of <1g / mL was selected for extraction to separate the organic phase and the aqueous product with a solid content of ≤1%, and the amount of ether added was 60% of the filtered liquid product by volume; The aqueous phase product with a solid content of ≤1% is used as a solvent for the hydrothermal liquefaction reaction of biomass and is used for a cyclic reaction; Step (4), separating and purifying the solute from the organic phase by a rotary evaporator, the obtained solute is bio-oil, further separating and purifying the bio-oil by a solid desiccant, recovering the organic solvent, and recycling it for the extraction and separation in the previous step; The gas-liquid separation kettle, filter press, extraction tank and rotary evaporator are connected through pipelines for continuous separation.

[0024] After testing, the yield of the obtained biomass hydrothermal liquefaction oil (bio-oil) was 29.91%.

[0025] Example 2

[0026] A novel method for post-treatment of biomass hydrothermal liquefaction reaction comprises the following steps: Step (1), performing gas-liquid separation on the mixture obtained after the hydrothermal liquefaction reaction of the biomass by means of a gas-liquid separation kettle to obtain a gas phase product and a primary liquid phase product; The mixture is a biomass hydrothermal liquefied mixture having a solid content of 20% obtained by hydrothermal reaction of biomass and water at a temperature of 370° C. and a pressure of 5 MPa; The biomass is a mixture of kitchen waste; Step (2), firstly performing solid-liquid pre-separation on the primary liquid phase product having a solid content of more than 15% by a centrifugal separation device to obtain a pre-separated solid phase product and a secondary liquid phase product having a solid content of ≤5%; Then, a mixture of a primary liquid phase product having a solid content of ≤15% and a secondary liquid phase product having a solid content of ≤5% is separated by a plate-and-frame filter to obtain a filtered solid phase product and a filtered liquid phase product having a solid content of ≤1%; The filter cloth of the plate-and-frame filter has a pore size of 0.5 mm; Step (3), selecting an extraction tower for continuous extraction, separation and enrichment according to the total weight of the solid phase product after filtration, the separation efficiency and separation effect required in actual work; According to the density of the residual solid phase in the filtered liquid product with a solid content of ≤1%, in this embodiment, an organic solvent-dichloromethane with a density of >1g / mL is selected for extraction to separate the organic phase and the aqueous phase product with a solid content of ≤1%, and the amount of dichloromethane added is 75% of the filtered liquid product by volume; The aqueous phase product with a solid content of ≤1% is used as a solvent for the hydrothermal liquefaction reaction of biomass and is used for a cyclic reaction; Step (4), separating and purifying the solute from the organic phase by a distillation tower, the obtained solute is bio-oil, further separating and purifying the bio-oil by using a solid desiccant, recovering the organic solvent, and recycling it for the extraction and separation in the previous step; The gas-liquid separation kettle, plate-and-frame filter, extraction tower and rectification tower are connected by pipelines for continuous separation.

[0027] After testing, the yield of the obtained biomass hydrothermal liquefaction oil (bio-oil) was 31.9%.

[0028] Example 3

[0029] A novel method for post-treatment of biomass hydrothermal liquefaction reaction comprises the following steps: Step (1), performing gas-liquid separation on the mixture obtained after the hydrothermal liquefaction reaction of the biomass by means of a gas-liquid separation kettle to obtain a gas phase product and a primary liquid phase product; The mixture is a biomass hydrothermal liquefied mixture having a solid content of 7.5% obtained by hydrothermal reaction of biomass and water at a temperature of 220° C. and a pressure of 10 MPa; The biomass is a mixture of municipal industrial solid wastewater and animal manure; Step (2), separating the primary liquid phase product with a solid content of ≤15% by using a Buchner funnel to obtain a filtered solid phase product and a filtered liquid phase product with a solid content of ≤1%; The filter cloth of the Buchner funnel has a micropore diameter of 0.5 mm; Step (3), selecting a separatory bottle for intermittent extraction, separation and enrichment according to the total weight of the solid phase product after filtration, the separation efficiency and separation effect required in actual work; According to the density of the residual solid phase in the filtered liquid product with a solid content of ≤1%, in this embodiment, an organic solvent-ethyl acetate with a density of <1 g / mL was selected for extraction to separate the organic phase and the aqueous phase product with a solid content of ≤1%, and the amount of ethyl acetate added was 75% of the filtered liquid product by volume; The aqueous phase product with a solid content of ≤1% is used as a solvent for the hydrothermal liquefaction reaction of biomass and is used for a cyclic reaction; Step (4), separating and purifying the solute from the organic phase by a rotary evaporator, the obtained solute is bio-oil, the bio-oil is further separated and purified by a solid desiccant, and the organic solvent is recovered and recycled for the previous extraction separation step.

[0030] After testing, the yield of the obtained biomass hydrothermal liquefaction oil (bio-oil) was 28.8%.

[0031] The present invention realizes high efficiency, low cost, environmental protection and significant quality improvement in the post-treatment process of biomass hydrothermal liquefaction reaction: 1. High efficiency: The comprehensive combination of gas-liquid separation technology, centrifugal separation technology, filtration separation technology, extraction and evaporation separation and other methods significantly improves the efficiency of solid-liquid separation and product purification; Among them, the gas-liquid separation kettle, filtering equipment, extraction equipment, and separation and purification equipment are connected through pipelines to achieve continuous separation; 2. Significant quality improvement: First, most of the solid impurities are removed through centrifugation and filtration, and then the separation quality of biomass oil is effectively improved through extraction, evaporation, drying and dehydration; 3. Low cost: The use and maintenance costs of multi-stage membrane separation technology alone are high. The comprehensive application of technologies can complement each other's advantages and effectively reduce separation costs. For example, according to the characteristics of the material, organic phases of different densities are selected for extraction to achieve oil-water separation and separation of some tiny solid particles.

[0032] 4. Good environmental protection: The continuous separation technology is adopted to avoid the secondary pollution that may be caused by traditional methods, and it has good environmental protection performance; the organic phase used in the extraction is recovered by rotary evaporation or distillation to achieve recycling; if the material reaction is not sufficient, the aqueous phase after extraction can be recycled to reduce wastewater discharge.

[0033] The above embodiments are merely preferred implementations of the present invention. Any simple modification, amendment and substitution of the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A novel method for post-treatment of biomass hydrothermal liquefaction reaction, characterized in that: The following steps are involved: Step (1), performing gas-liquid separation on the mixture obtained after the hydrothermal liquefaction reaction of the biomass by means of a gas-liquid separation kettle to obtain a gas phase product and a primary liquid phase product; The mixture is a biomass hydrothermal liquefied mixture having a solid content of 2.5% to 20% obtained by hydrothermal reaction of biomass and water at a temperature of 200° C. to 370° C. and a pressure of 5 MPa to 22 MPa; Step (2), firstly performing solid-liquid pre-separation on the primary liquid phase product having a solid content of more than 15% by a centrifugal separation device to obtain a pre-separated solid phase product and a secondary liquid phase product having a solid content of ≤5%; Then, a mixture of a primary liquid phase product having a solid content of ≤15% and a secondary liquid phase product having a solid content of ≤5% is separated by a filtering device to obtain a filtered solid phase product and a filtered liquid phase product having a solid content of ≤1%; Step (3), according to the total weight of the solid phase product after filtration, select an extraction device for extraction, separation and enrichment; according to the density of the residual solid phase in the liquid phase product after filtration with a solid content of ≤1%, select different organic solvents for extraction to separate the organic phase and the aqueous phase product with a solid content of ≤1%, as follows: If the density of the residual solid phase is greater than that of water, an organic solvent with a density of <1 g / mL is selected to extract the liquid phase product after filtration; if the density of the residual solid phase is less than that of water, an organic solvent with a density of >1 g / mL is selected to extract the liquid phase product after filtration; Step (4), separating and purifying the solute from the organic phase by separation and purification equipment, the obtained solute is bio-oil, and the organic solvent is recovered and recycled for the previous extraction and separation step.

2. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (1), the biomass is selected from one or more of animal manure and kitchen waste, municipal industrial solid wastewater, and fibrous or wood fibrous materials.

3. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (2), the filtering device is a funnel, a filter press or a filter; the filter cloth of the filtering device has a pore size of <1 mm.

4. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (3), the extraction equipment is an intermittent extraction equipment or a continuous extraction equipment. The intermittent extraction equipment is a separatory bottle or an extraction tank. The continuous extraction equipment is an extraction machine or an extraction tower.

5. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (3), the organic solvent with a density <1 g / mL is ethyl acetate or ether, and the organic solvent with a density >1 g / mL is dichloromethane or tetrachloromethane.

6. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (3), the amount of organic solvent added is 5% to 100% by volume of the liquid phase product after filtration.

7. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (3), the aqueous phase product with a solid content of ≤1% is used as a solvent for the hydrothermal liquefaction reaction of biomass for a cyclic reaction.

8. The novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: Step (4), using a solid desiccant to further separate and purify the bio-oil.

9. A novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: In step (4), the separation and purification equipment is a rotary evaporator or a distillation tower.

10. The novel method for post-treatment of biomass hydrothermal liquefaction reaction according to claim 1, characterized in that: The gas-liquid separation kettle, filtering equipment, extraction equipment and separation and purification equipment are connected through pipelines for continuous separation.