阅读说明：本技术 一种利用梯度水热液化技术促进杨木向邻苯二甲酸二丁酯高效转化的方法 (Method for promoting efficient conversion of poplar wood to dibutyl phthalate by utilizing gradient hydrothermal liquefaction technology ) 是由 徐建 吴海军 杨超华 左宗涛 顾帅令 王标 张楷 徐霞 于 2020-12-24 设计创作，主要内容包括：本发明公开了一种利用梯度水热液化技术促进杨木向邻苯二甲酸二丁酯高效转化的方法,该方法将液化温度设计为三个温度点,将原料和均相催化剂放入反应釜内,先升温至第一温度点停留一定时间后放置冷却堆,取出产物并分离出残渣SR；水相通过旋蒸浓缩为LO,SR通过洗脱剂洗脱分为残渣相和LO相,然后将上一步的残渣烘干再继续做下一步的水热液化；所选用的固液比跟前一步的一致,然后升温至第二温度点停留相同时间后放置冷却堆,按照第一反应阶段一致的分离和浓缩,直至第三温度点液化后停止梯度液化。本发明利用梯度水热液化能够使得杨木各组分实现最优的液化形式,极大提升油相中邻苯二甲酸二丁酯的单体收率。(The invention discloses a method for promoting poplar to be converted into dibutyl phthalate with high efficiency by utilizing a gradient hydrothermal liquefaction technology, which comprises the steps of designing liquefaction temperature into three temperature points, putting raw materials and a homogeneous catalyst into a reaction kettle, heating to the first temperature point, staying for a certain time, placing a cooling pile, taking out a product and separating out residue SR; concentrating the water phase into LO by rotary evaporation, eluting SR with eluent to separate into residue phase and LO phase, drying the residue in the previous step, and performing hydrothermal liquefaction in the next step; and (3) the solid-liquid ratio of the selected solid-liquid ratio is consistent with that of the previous step, then the temperature is increased to a second temperature point, the cooling pile is placed after the temperature is kept for the same time, the separation and the concentration are consistent according to the first reaction stage, and the gradient liquefaction is stopped until the third temperature point is liquefied. According to the invention, the optimal liquefaction form of each component of the poplar can be realized by utilizing gradient hydrothermal liquefaction, and the monomer yield of dibutyl phthalate in the oil phase is greatly improved.)

1. A method for promoting efficient conversion of poplar wood to dibutyl phthalate by utilizing a gradient hydrothermal liquefaction technology is characterized by comprising the following steps of:

(1) taking poplar chips and distilled water according to a solid-to-liquid ratio of 8-12%, then taking a homogeneous catalyst solution, putting the poplar chips and the distilled water together into a high-pressure reaction kettle for hydrothermal liquefaction reaction, wherein the reaction temperature is 210-230 ℃, the residence time at the temperature is 15-25min, cooling after the reaction is finished, taking out substances in the kettle, separating filtrate and residues after the filtration by using filter paper, carrying out rotary evaporation and concentration on the filtrate after the filtration to obtain light oil at 53-57 ℃, fully eluting the residues after the filtration by using an eluent, then carrying out suction filtration by using the filter paper, separating the residues after the elution from a liquid phase, carrying out rotary evaporation and concentration on the liquid phase at the moment to obtain heavy oil at 28-32 ℃, and drying the residues after the elution;

(2) taking the residue obtained in the step (1) and distilled water according to a solid-liquid ratio of 8-12%, then taking a homogeneous catalyst, putting the homogeneous catalyst and the residue into a high-pressure reaction kettle together for hydrothermal liquefaction reaction at the reaction temperature of 250-270 ℃, keeping the temperature for 15-25min, cooling after the reaction is finished, taking out substances in the kettle, separating filtrate and residue after suction filtration by using filter paper, carrying out rotary evaporation and concentration on the filtrate after suction filtration by 53-57 ℃ to obtain light oil, fully eluting the residue after suction filtration by using an eluant, then separating the residue after elution from a liquid phase by using the suction filtration filter paper, carrying out rotary evaporation and concentration on the liquid phase at the moment by 28-32 ℃ to obtain heavy oil, and drying the residue after elution;

(3) taking the residue obtained in the step (2) and distilled water according to a solid-liquid ratio of 8-12%, then taking a homogeneous catalyst, putting the homogeneous catalyst and the residue into a high-pressure reaction kettle together for hydrothermal liquefaction reaction at the reaction temperature of 290 ℃ and 310 ℃, keeping the temperature for 15-25min, cooling after the reaction is finished, taking out substances in the kettle, separating filtrate and residue after suction filtration by using filter paper, carrying out rotary evaporation and concentration on the filtrate after suction filtration by 53-57 ℃ to obtain light oil, fully eluting the residue after suction filtration by using an eluant, then separating the residue after elution from a liquid phase by using the suction filtration filter paper, carrying out rotary evaporation and concentration on the liquid phase at the moment by 28-32 ℃ to obtain heavy oil, and drying the residue after elution;

(4) stopping the gradient hydrothermal liquefaction reaction, and collecting the oil phase products obtained in the steps.

2. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: in the step (1), the poplar wood chips are crushed into particles with the particle size of 20-100 meshes.

3. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: in the steps (1) to (3), the reaction temperature of the hydrothermal liquefaction reaction in the high-pressure reaction kettle is 220 ℃, 260 ℃ and 300 ℃ in sequence.

4. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: in the steps (1) to (3), the retention time is 20min at the temperature point of the hydrothermal liquefaction reaction.

5. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: in the steps (1) to (3), the mass of the catalyst in the homogeneous catalyst solution is 0.5-1.5%, preferably 1%, of the mass of the dry sample of the raw material in the step.

6. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: in the steps (1) to (3), the eluent is dichloromethane.

7. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: and (3) in the steps (1) to (3), performing rotary evaporation and concentration on the filtrate after suction filtration at 55 ℃ to obtain light oil.

8. The method for promoting efficient conversion of poplar to dibutyl phthalate by using the gradient hydrothermal liquefaction technology according to claim 1, wherein the method comprises the following steps: and (3) separating the residue after elution from the liquid phase, concentrating the liquid phase into heavy oil by rotary evaporation at 30 ℃, and drying the residue after elution.

Technical Field

The invention relates to the technical field of agricultural waste conversion and utilization, in particular to a method for promoting efficient conversion of poplar to dibutyl phthalate by utilizing a gradient hydrothermal liquefaction technology.

Background

China is a world-wide energy country and has abundant biomass resources. The biomass has the characteristics of low sulfur, nitrogen and ash, and the absorption of carbon dioxide in the growth of the biomass and the emission of carbon dioxide brought by the conversion of the biomass can maintain a balanced relationship, so that the application of the biomass is more and more favored by more researchers. With the continuous progress of scientific technology and the increasing shortage of fossil resources, the problem of energy shortage is urgently solved, so that biomass occupies an increasingly important position in renewable energy. In order to realize clean conversion of biomass, technologies such as combustion, pyrolysis, fermentation and hydrolysis are developed in sequence, and hydrothermal liquefaction is a research hotspot for realizing efficient conversion of biomass in recent years.

In the prior art, many researches on biomass treatment by a hydrothermal liquefaction technology are limited to researches on a certain temperature and a certain liquefaction time, and a great deal of reports are not provided for a gradient hydrothermal liquefaction technology. The poplar is used as a hardwood, and has higher hemicellulose content than common softwoods, so that the poplar is more sustainable resources for producing and preparing biological fuels and other chemicals through saccharification and fermentation. But the yield of the obtained product is low due to the complexity of its structure. The poplar is used as a better hydrothermal liquefaction raw material to prepare the bio-oil, wherein the higher content of hemicellulose and cellulose can liquefy most of the bio-oil in a lower temperature range. Different components are liquefied at different temperatures, hemicellulose can be completely liquefied in a lower temperature range, and compared with the hemicellulose, the liquefaction temperature of the cellulose is higher. Because the structure of the lignin is relatively stubborn, the liquefaction temperature range of the lignin is relatively wide, and the lignin is liquefied from 200 ℃ to 450 ℃. However, the current research on hydrothermal liquefaction of biomass focuses on the change of various condition parameters and the selection of some high-efficiency catalysts, and the condition parameters (temperature, time, solid-to-liquid ratio, etc.) can have a great influence on hydrothermal liquefaction, especially on temperature, but from the viewpoint of the mutual combination of efficient conversion and economic applicability, a single hydrothermal liquefaction from one temperature point cannot be used as an economic hydrothermal liquefaction mode, and excessive gaseous products can be generated. Gradient hydrothermal liquefaction is a relatively economical liquefaction mode that can sufficiently liquefy the components of biomass in different temperature ranges, while suppressing the conversion of oil phase products to gas phase products and thereby reducing the yield of gaseous products.

In previous researches, the one-step method for catalyzing hydrothermal liquefaction has to rely on a high-efficiency catalyst to liquefy biomass to obtain high-conversion-rate bio-oil, and although the method has a remarkable effect, more catalysis is limited to homogeneous catalysis and is difficult to recycle, and the cost of hydrothermal liquefaction is very high over time.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a method for promoting the efficient conversion of poplar to dibutyl phthalate by utilizing a gradient hydrothermal liquefaction technology.

In order to achieve the technical purpose and achieve the technical effect, the invention is realized by the following technical scheme:

a method for promoting efficient conversion of poplar wood to dibutyl phthalate by utilizing a gradient hydrothermal liquefaction technology comprises the following steps:

(1) taking poplar chips and distilled water according to a solid-to-liquid ratio of 8-12%, then taking a homogeneous catalyst solution, putting the poplar chips and the distilled water together into a high-pressure reaction kettle for hydrothermal liquefaction reaction, wherein the reaction temperature is 210-230 ℃, the residence time at the temperature is 15-25min, cooling after the reaction is finished, taking out substances in the kettle, separating filtrate and residues after the filtration by using filter paper, carrying out rotary evaporation and concentration on the filtrate after the filtration to obtain light oil at 53-57 ℃, fully eluting the residues after the filtration by using an eluent, then carrying out suction filtration by using the filter paper, separating the residues after the elution from a liquid phase, carrying out rotary evaporation and concentration on the liquid phase at the moment to obtain heavy oil at 28-32 ℃, and drying the residues after the elution;

(2) taking the residue obtained in the step (1) and distilled water according to a solid-liquid ratio of 8-12%, then taking a homogeneous catalyst, putting the homogeneous catalyst and the residue into a high-pressure reaction kettle together for hydrothermal liquefaction reaction at the reaction temperature of 250-270 ℃, keeping the temperature for 15-25min, cooling after the reaction is finished, taking out substances in the kettle, separating filtrate and residue after suction filtration by using filter paper, carrying out rotary evaporation and concentration on the filtrate after suction filtration by 53-57 ℃ to obtain light oil, fully eluting the residue after suction filtration by using an eluant, then separating the residue after elution from a liquid phase by using the suction filtration filter paper, carrying out rotary evaporation and concentration on the liquid phase at the moment by 28-32 ℃ to obtain heavy oil, and drying the residue after elution;

(3) taking the residue obtained in the step (2) and distilled water according to a solid-liquid ratio of 8-12%, then taking a homogeneous catalyst, putting the homogeneous catalyst and the residue into a high-pressure reaction kettle together for hydrothermal liquefaction reaction at the reaction temperature of 290 ℃ and 310 ℃, keeping the temperature for 15-25min, cooling after the reaction is finished, taking out substances in the kettle, separating filtrate and residue after suction filtration by using filter paper, carrying out rotary evaporation and concentration on the filtrate after suction filtration by 53-57 ℃ to obtain light oil, fully eluting the residue after suction filtration by using an eluant, then separating the residue after elution from a liquid phase by using the suction filtration filter paper, carrying out rotary evaporation and concentration on the liquid phase at the moment by 28-32 ℃ to obtain heavy oil, and drying the residue after elution;

(4) stopping the gradient hydrothermal liquefaction reaction, and collecting the oil phase products obtained in the steps.

Further, according to the method for promoting efficient conversion of poplar wood to dibutyl phthalate by utilizing the gradient hydrothermal liquefaction technology, in the step (1), the poplar wood chips are crushed, and the crushed particle size is 20-100 meshes.

Further, in the method for promoting the efficient conversion of poplar wood to dibutyl phthalate by using the gradient hydrothermal liquefaction technology, in the steps (1) to (3), the reaction temperature of the hydrothermal liquefaction reaction in the high-pressure reaction kettle is 220 ℃, 260 ℃ and 300 ℃ in sequence.

Further, in the method for promoting the efficient conversion of poplar wood to dibutyl phthalate by using the gradient hydrothermal liquefaction technology, the retention time at the temperature point of the hydrothermal liquefaction reaction in the steps (1) to (3) is 20 min.

Further, in the method for promoting the efficient conversion of poplar wood to dibutyl phthalate by using the gradient hydrothermal liquefaction technology, in the steps (1) to (3), the mass of the catalyst in the homogeneous catalyst solution is 0.5-1.5%, preferably 1%, of the mass of the raw material in the step.

Further, in the method for promoting the efficient conversion of poplar wood to dibutyl phthalate by using the gradient hydrothermal liquefaction technology, in the steps (1) to (3), the eluent is dichloromethane.

Further, in the method for promoting the efficient conversion of poplar wood to dibutyl phthalate by utilizing the gradient hydrothermal liquefaction technology, in the steps (1) to (3), the filtrate after suction filtration is subjected to rotary evaporation at 55 ℃ and concentrated into light oil.

Further, in the method for promoting the efficient conversion of poplar wood to dibutyl phthalate by utilizing the gradient hydrothermal liquefaction technology, in the steps (1) to (3), the eluted residue is separated from the liquid phase, the liquid phase is concentrated into heavy oil by rotary evaporation at 30 ℃, and the eluted residue is dried.

The invention has the beneficial effects that:

the method directly takes poplar chips as experimental raw materials, does not need washing and drying, puts the poplar chips and a catalyst into a reaction kettle according to a certain solid-liquid ratio, designs the liquefaction temperature into three temperature points, utilizes gradient hydrothermal liquefaction to realize the optimal liquefaction form of each component of poplar, greatly improves the monomer yield of dibutyl phthalate in an oil phase, and further develops the poplar HTL product to commercialization.

Of course, it is not necessary for any one product that embodies the invention to achieve all of the above advantages simultaneously.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The following embodiments are relevant to the present invention:

example 1

The poplar chips are crushed into slightly fine powder chips without drying, the water content of the powder chips is measured by a moisture meter, 70 g of dry sample (absolute dry mass after water content is deducted) is taken as a raw material for hydrothermal liquefaction, 700ml of distilled water is taken according to the solid-to-liquid ratio of 10 wt%, and 1 wt% (based on the raw material dry sample) of Na is taken₂CO₃As a base catalyst, 700ml of distilled water was placed. Placing the above materials and solution into 1.2L high pressure reaction kettle, reacting at gradient HTL220 deg.C for 20min, cooling, taking out the kettle, filtering with filter paper, separating filtrate and residue, and concentrating the filtrate into Light Oil (LO) by rotary evaporation at 55 deg.C₁). Then sufficiently eluting the residue after suction filtration with 400ml dichloromethane, suction filtering with filter paper, separating the eluted residue from the liquid phase, and concentrating the liquid phase into Heavy Oil (HO) by rotary evaporation at 30 deg.C₁) At this time, the residue after elution is dried (SR)₁) (ii) a Will SR₁Continuing to obtain the powder according to the solid-to-liquid ratio of 10 percent and the Na of 1 percent₂CO₃Continuously performing alkali catalysis at 260 deg.C under HTL, standing at the temperature for 20min, cooling after reaction, taking out the substance in the kettle, filtering with filter paper, separating filtrate and residue, and concentrating the filtrate into Light Oil (LO) by rotary evaporation at 55 deg.C₂). Then sufficiently eluting the residue after suction filtration with 400ml dichloromethane, then suction filtration with filter paper, separating the eluted residue from the liquid phase, and concentrating the liquid phase by rotary evaporation at 30 DEG CCondensed into Heavy Oil (HO)₂) At this time, the residue after elution is dried (SR)₂) (ii) a Will SR₂Continuing to obtain the powder according to the solid-to-liquid ratio of 10 percent and the Na of 1 percent₂CO₃Continuously performing alkali catalysis at 300 deg.C under HTL, standing at the temperature for 20min, cooling after reaction, taking out the substance in the kettle, filtering with filter paper, separating filtrate and residue, and concentrating the filtrate into Light Oil (LO) by rotary evaporation at 55 deg.C₃). Then sufficiently eluting the residue after suction filtration with 400ml dichloromethane, suction filtering with filter paper, separating the eluted residue from the liquid phase, and concentrating the liquid phase into Heavy Oil (HO) by rotary evaporation at 30 deg.C₃) At this time, the residue after elution is dried (SR)₃)。

The oil phase products (LO)₁、LO₂、LO₃；HO₁、HO₂、HO₃) GC-MS detection was performed. Analysis shows that DBP is mainly and intensively distributed in HO, and DBP yields of three temperature points (220 ℃, 260 ℃ and 300 ℃) of the step HTL are respectively 37.40 percent, 60.09 percent and 83.88 percent.

Comparative example 1

The poplar chips are crushed into slightly fine powder chips without drying, the water content of the powder chips is measured by a moisture meter, 70 g of dry sample (absolute dry mass after water content is deducted) is taken as a raw material for hydrothermal liquefaction, 700ml of distilled water is taken according to the solid-to-liquid ratio of 10 wt%, and 1 wt% (based on the raw material dry sample) of Na is taken₂CO₃As a base catalyst, 700ml of distilled water was placed. Putting the above raw materials and solution into 1.2L high pressure reactor, reacting at 260 deg.C with one-step HTL (where residue is not liquefied again), standing for 20min, cooling after reaction, taking out the reactor, filtering with filter paper, separating filtrate and residue, and concentrating the filtrate into Light Oil (LO) by rotary evaporation at 55 deg.C. Then, the residue after the suction filtration was sufficiently eluted with 400ml of dichloromethane, and then, the residue after the suction filtration was suction-filtered with filter paper, and the residue after the elution was separated from the liquid phase, and the liquid phase was concentrated into Heavy Oil (HO) by rotary evaporation at 30 ℃.

GC-MS detection of the oil phase products was carried out. The dibutyl phthalate yield of the oil phase product at the temperature point is 34.02% by analysis.

Comparative example 2

The poplar chips are crushed into slightly fine powder chips without drying, the water content of the powder chips is measured by a moisture meter, 70 g of dry sample (absolute dry mass after water content is deducted) is taken as a raw material for hydrothermal liquefaction, 700ml of distilled water is taken according to the solid-to-liquid ratio of 10 wt%, and 1 wt% (based on the raw material dry sample) of Na is taken₂CO₃As a base catalyst, 700ml of distilled water was placed. Putting the above raw materials and solution into 1.2L high pressure reaction kettle, reacting at 300 deg.C with one-step HTL (no re-liquefaction of residue) for 20min, cooling, taking out the kettle, filtering with filter paper, separating filtrate and residue, and concentrating the filtrate into Light Oil (LO) by rotary evaporation at 55 deg.C. Then, the residue after the suction filtration was sufficiently eluted with 400ml of dichloromethane, and then, the residue after the suction filtration was suction-filtered with filter paper, and the residue after the elution was separated from the liquid phase, and the liquid phase was concentrated into Heavy Oil (HO) by rotary evaporation at 30 ℃.

GC-MS detection of the oil phase products was carried out. The dibutyl phthalate yield of the oil phase product at the temperature point is 8.96% by analysis.

The invention directly takes poplar sawdust as an experimental raw material, does not need washing and drying, and is put into a reaction kettle according to a certain solid-liquid ratio. The liquefaction temperature is designed to be 220 ℃, 260 ℃ and 300 ℃ at three points, raw materials with certain solid-liquid ratio (poplar: water) and homogeneous catalysts with certain concentration are put into a reaction kettle, the temperature is firstly raised to 220 ℃ for a certain time, then the reaction kettle is placed in a cooling pile, products are taken out, and residues (SR) are separated. And the water phase is concentrated into LO through rotary evaporation, SR is separated into a residue phase and an LO phase through elution by an eluant, and then the residue in the previous step is dried and is continuously subjected to hydrothermal liquefaction in the next step. The solid-liquid ratio of the selected solid-liquid ratio is consistent with that of the previous step, then the temperature is increased to 260 ℃, the cooling pile is placed after the same time of residence, the separation and the concentration are consistent according to the first reaction stage, and the gradient liquefaction is stopped until the liquefaction is carried out at 300 ℃. The invention has the following characteristics and advantages: 1) simple temperature gradient adjustment without excessive catalysis. 2) The liquefaction temperature is relatively low and the energy consumption is lower. 3) Can obviously improve the yield of the monomer (DBP) in the oil phase product and reduce the generation of gas phase products.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.