阅读说明：本技术 抑制生物油受热结焦的方法 (Method for inhibiting biological oil from being coked by heating ) 是由 汪一 肖桂雨 熊哲 马立群 邓伟 向军 胡松 苏胜 江龙 徐俊 于 2021-09-22 设计创作，主要内容包括：本发明提供一种抑制生物油受热结焦的方法,包括如下步骤：在受热体系中加入自由基抑制剂。所述自由基抑制剂为单环环类、多环环类或含杂原子类的有机物。本发明使用单环环类、多环环类或含杂原子类等高含氢量的有机物如：均三甲苯、均四甲苯、二氢菲、四氢化萘、二苯并噻吩、氮甲基吡咯烷酮等作为自由基抑制剂,其易于与生物油进行混合,能有效降低抑制生物油加热过程中焦炭的产生。本发明还提供一种自由基抑制剂在抑制生物油受热结焦中的应用。(The invention provides a method for inhibiting biological oil from being heated and coked, which comprises the following steps: adding a free radical inhibitor into the heated system. The free radical inhibitor is monocyclic ring, polycyclic ring or organic matter containing hetero atom class. The invention uses high hydrogen content organic matters such as monocyclic ring, polycyclic ring or heteroatom-containing organic matters, such as: mesitylene, durene, dihydrophenanthrene, tetralin, dibenzothiophene, nitrogen methyl pyrrolidone and the like are used as free radical inhibitors, and the free radical inhibitors are easy to mix with the biological oil and can effectively reduce and inhibit the generation of coke in the heating process of the biological oil. The invention also provides application of the free radical inhibitor in inhibiting the heating coking of the bio-oil.)

1. A method for inhibiting biological oil from being coked by heating is characterized by comprising the following steps: adding a free radical inhibitor into the heated system.

2. The method for inhibiting bio-oil from being coked by heat according to claim 1, wherein the radical inhibitor is an organic compound having a monocyclic ring type, a polycyclic ring type or a heteroatom-containing type.

3. The method for inhibiting bio-oil from being coked by heat according to claim 2, wherein the monocyclic ring organic compound is mesitylene or durene; the polycyclic organic matter is dihydrophenanthrene or tetrahydronaphthalene; the heteroatom organic matter is dibenzothiophene or nitrogen methyl pyrrolidone.

4. The method for inhibiting the biological oil from being coked by heating according to claim 1, wherein the mass ratio of the biological oil to the free radical inhibitor in the heating system is 1 (0.5-10).

5. The method for inhibiting the biological oil from being coked by heating according to claim 1, wherein the temperature of the heated system is 300-600 ℃.

6. The method for inhibiting the coking of biological oil by heating according to claim 1, further comprising the steps of: mixing biological oil and free radical inhibitor.

7. The method of claim 1, wherein when the free radical inhibitor is in a solid state, the method further comprises dissolving the free radical inhibitor in an organic solvent prior to adding the free radical inhibitor to the heated system.

8. The method for inhibiting bio-oil from being coked by heat according to claim 7, wherein the organic solvent is selected from one or more of methanol, dichloromethane and carbon disulfide.

9. An application of a free radical inhibitor in inhibiting the heating coking of bio-oil.

10. The use according to claim 9, wherein the free radical inhibitor is an organic compound of the monocyclic, polycyclic or heteroatom-containing class;

preferably, the monocyclic ring organic compound is mesitylene or durene; the polycyclic organic matter is dihydrophenanthrene or tetrahydronaphthalene; the heteroatom organic matter is dibenzothiophene or nitrogen methyl pyrrolidone;

more preferably, the free radical inhibitor is dihydrophenanthrene or dibenzothiophene.

Technical Field

The invention relates to the field of biomass utilization, in particular to a method for inhibiting heating and coking of bio-oil.

Background

The biomass has the characteristics of cleanness, reproducibility, wide distribution, carbon neutrality and the like. The development of the biomass utilization technology is beneficial to optimizing the energy supply structure of China and relieving the increasingly severe environmental problems. Bio-oil is a condensable product in biomass pyrolysis process, is a very promising alternative to fossil fuels, and has wide application. For example, bio-oils have the potential to be used for producing syngas/hydrogen rich fuels through gasification/steam reforming and other processes, producing bio-fuel oil through catalytic cracking/catalytic hydrogenation, and for supplying heat/generating electricity through combustion, and the like. Most potential conversion utilization means of the bio-oil involve the heat treatment process of the bio-oil.

The biological oil heating coking is one of the problems to be solved urgently in the biological oil heat utilization at present, but the mechanism in the biological oil heat utilization process is not completely clear at present due to the quite complex composition of the biological oil. According to the current research reports at home and abroad, the research on the biological oil coking mechanism mainly comprises the following four parts: (1) the bio-oil has strong polymerization tendency, and the polymerization reaction of the bio-oil components is obviously accelerated by heating the bio-oil to generate solid carbon-based substances; (2) there is significant interaction between the different components of the bio-oil, and the presence of interaction also promotes coking of the bio-oil. This observation is corroborated by the fact that the sum of the coke yields from the individual pyrolysis of the bio-oil component is less than the coke yield from the pyrolysis of the original bio-oil; (3) different temperatures, heating rates and reaction times in the pyrolysis process can influence the coking of the bio-oil; (4) the volatile matter produced in the biological oil pyrolysis process can have secondary reaction, namely the volatile matter can be polymerized to produce carbon, namely secondary coking, and the secondary coking reaction is stronger when the temperature is higher.

The production of carbon deposition of the bio-oil under heated conditions hinders the potential utilization of the bio-oil. For example, when bio-oil is subjected to catalytic cracking or hydro-upgrading, the generation of coke can deactivate the catalyst and also cause the blockage of the reactor, thereby greatly reducing the utilization rate of organic components in the bio-oil. In the combustion and utilization of the bio-oil, the formation of the bio-oil coke before entering a boiler causes problems such as nozzle blockage and the like, and operation accidents are easy to occur. When pyrolysis tar is used for processing fuel oil and chemicals, heat transfer between a pipe wall and fluid is often influenced by the formation of coke in a pipeline of tar processing equipment, so that the system cannot normally operate. Catalytic fast pyrolysis of bio-oil is an effective method for producing high quality aromatic-rich liquid oil, but the high coke yield of bio-oil pyrolysis prevents the implementation of this process, etc.

Therefore, how to reduce the characteristic of coking in the heat utilization process of the bio-oil has important significance for improving the heat chemical utilization performance of the bio-oil.

Disclosure of Invention

The present invention is directed to solving at least some of the problems associated with the prior art, and in a first aspect of the invention, there is provided a method for inhibiting heated coking of bio-oil, comprising the steps of: adding a free radical inhibitor into the heated system.

In one or more embodiments of the present invention, the radical inhibitor is a monocyclic ring, a polycyclic ring, or a heteroatom-containing organic.

Preferably, the free radical inhibitor is a high hydrogen content organic of monocyclic ring, polycyclic ring or heteroatom-containing class.

In the process of researching the heating coking of the bio-oil, the inventor surprisingly finds that the organic matter with high hydrogen content can inhibit the heating coking of the bio-oil, and the principle of the method is that the organic matter with high hydrogen content can provide hydrogen for free radicals in a reaction, so that the free radicals are hydrogenated to inhibit the original reaction process of the free radicals, and the effect of the heating coking of the bio-oil is achieved. Further, the inventors have conducted further studies on monocyclic rings, polycyclic rings or heteroatom-containing groups having a high hydrogen content. The compounds have obvious inhibition effect on the heating coking of the bio-oil.

In one or more embodiments of the present invention, the monocyclic ring organic is mesitylene or durene; the polycyclic organic matter is dihydrophenanthrene or tetrahydronaphthalene; the heteroatom organic matter is dibenzothiophene or nitrogen methyl pyrrolidone. Preferably, the free radical inhibitor is dihydrophenanthrene or dibenzothiophene.

Mesitylene and durene are monocyclic aromatic hydrocarbons with branched chains, and can inhibit the generation of free radicals in the thermal reaction process of the bio-oil in a hydrogen transfer mode;

dihydrophenanthrene, tetrahydronaphthalene, dibenzothiophene and N-methyl pyrrolidone supply hydrogen to free radicals to inhibit the generation of free radicals in the thermal reaction process of the bio-oil so as to inhibit the thermal coking of the bio-oil.

Mesitylene, durene, dihydrophenanthrene, tetralin, dibenzothiophene and nitrogen methyl pyrrolidone have high hydrogen content, and can provide hydrogen for free radicals in the reaction, so that the free radicals are hydrogenated to inhibit the original reaction process of the free radicals, and the effect of heating and coking the bio-oil is further achieved.

In one or more embodiments of the present invention, in the heated system, the mass ratio of bio-oil to free radical inhibitor is 1:

(0.5～10)。

in one or more embodiments of the present invention, the temperature of the heated system is 300 to 600 ℃.

In one or more embodiments of the present invention, the method for inhibiting bio-oil from being coked by heat further comprises the following steps: mixing biological oil and free radical inhibitor.

In one or more embodiments of the present invention, when the radical inhibitor is in a solid state, before adding the radical inhibitor to the heated system, the method further comprises dissolving the radical inhibitor in an organic solvent.

In one or more embodiments of the present invention, the organic solvent is selected from one or more of methanol, dichloromethane, and carbon disulfide.

In a second aspect of the invention, the invention provides the use of a free radical inhibitor for inhibiting heated coking of bio-oil.

In one or more embodiments of the invention, the free radical inhibitor is an organic compound of a monocyclic ring, a polycyclic ring, or a heteroatom-containing class; preferably, the monocyclic ring organic compound is mesitylene or durene; the polycyclic organic matter is dihydrophenanthrene or tetrahydronaphthalene; the heteroatom organic matter is dibenzothiophene or nitrogen methyl pyrrolidone. More preferably, the free radical inhibitor is dihydrophenanthrene or dibenzothiophene.

In one or more embodiments of the invention, a solvent which is miscible with the bio-oil is used for separating solid matters in the product after the heating reaction, and the separated solid sample is dried and quantified by using a drying oven; the parameters of the drying box are preferably 0.3-1 Mpa and 35-40 ℃; the coke material obtained after drying was quantified by a differential method.

The free radical content of the thermal reaction product was detected using an electron paramagnetic resonance spectrometer (EPR).

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the invention uses high hydrogen content organic matters such as monocyclic ring, polycyclic ring or heteroatom-containing organic matters, such as: mesitylene, durene, dihydrophenanthrene, tetralin, dibenzothiophene, nitrogen methyl pyrrolidone and the like are used as free radical inhibitors, and the free radical inhibitors are easy to mix with the biological oil and can effectively reduce and inhibit the generation of coke in the heating process of the biological oil.

2. The invention provides an application of a free radical inhibitor in inhibition of heating and coking of bio-oil.

Drawings

FIG. 1 is a schematic flow chart of heated coking of bio-oil with addition of a free radical inhibitor in an embodiment of the present invention;

FIG. 2 is a graph showing the effect of Dibenzothiophene (DBS) on coke yield in the pyrolysis reaction of bio-oil with the addition of free radical inhibitor (DHP) and the addition of free radical inhibitor (DBS) without the addition of free radical inhibitor;

FIG. 3 is a graph comparing the effect of adding different amounts of free radical inhibitor (mass ratio of bio-oil to free radical inhibitor of 1: 0, 1: 0.5, 1: 1, 1: 10) on coke yield in the pyrolysis reaction of bio-oil;

FIG. 4 is a graph showing a comparison of DHP consumption in a heated system at different temperatures (300 ℃, 400 ℃, 600 ℃).

Detailed Description

The schematic flow diagram of the heating and coking process of the bio-oil added with the free radical inhibitor in the embodiment of the invention is shown in figure 1, and the specific steps comprise the following steps:

step 1): fully stirring the biological oil and the free radical inhibitor, and uniformly mixing;

step 2): heating the uniformly mixed bio-oil and the free radical inhibitor;

step 3): separating the product after the heating treatment to obtain tar and coke;

step 4): the coke yield was quantitatively analyzed and the free radical content of the product was measured using an electron paramagnetic resonance spectrometer (EPR).

In addition, when the free radical inhibitor is in a solid state, dissolving the free radical inhibitor in an organic solvent is included before adding the free radical inhibitor to the heated system. The organic solvent is selected from one or more of methanol, dichloromethane or carbon disulfide.

Separating solid matters in the product after the heating reaction by using a solvent which is mutually soluble with the biological oil, drying the separated solid sample by using a drying oven, and quantifying by using a subtraction method;

the free radical content of the thermal reaction product was detected using an electron paramagnetic resonance spectrometer (EPR).

The scheme of the invention will be explained with reference to the examples. It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The methods used are conventional methods known in the art unless otherwise specified, and the consumables and reagents used are commercially available unless otherwise specified. Unless otherwise defined, technical and scientific terms used herein have the same meaning as is familiar to those skilled in the art. In addition, any methods or materials similar or equivalent to those described herein can also be used in the present invention.

Example 1: (Effect of different free radical inhibitors on coking in Bio-oil pyrolysis reactions)

Step 1): dissolving Dibenzothiophene (DBS) solid in methanol to obtain a methanol solution of Dibenzothiophene (DBS) solid;

step 2): biological oil (sample 1), biological oil and radical inhibitor Dihydrophenanthrene (DHP) were mixed at a ratio of 1: 1 (sample 2), a methanol solution of bio-oil and radical inhibitor Dibenzothiophene (DBS) (mass ratio of bio-oil to radical inhibitor Dibenzothiophene (DBS) 1: 1) was thoroughly stirred and mixed (sample 3), and then the three samples were added to a quartz reactor;

step 3): respectively putting the quartz reactors respectively filled with the three samples obtained in the step 2) into a vertical furnace under the atmosphere of high-purity nitrogen (99.999%), wherein the bottom of the quartz reactor is positioned at the center of a hearth of the vertical furnace for heating, and the pyrolysis temperature is 400 ℃;

step 4): repeating the steps 1) to 3), and controlling the reaction time to be 5min, 10min, 15min, 20min, 30min, 40min and 60min respectively;

step 5): after the reaction is finished, taking out the quartz reactor in the vertical furnace, and cooling in ice-water bath;

step 6): products after the pyrolysis reaction of the reactants in the three quartz reactors were separated using a mixed solution (methanol: dichloromethane ═ 1: 4 (volume ratio)) in which a solid product insoluble was called coke. The solids were dried using a vacuum oven and the coke was quantitatively analyzed using a subtraction method and the free radical content of the product was measured using an electron paramagnetic resonance spectrometer (EPR).

FIG. 2 shows the effect of Dibenzothiophene (DBS) without, with, and with free radical inhibitors Dihydrophenanthrene (DHP) and DBS on coking in the pyrolysis of bio-oil. It can be seen from fig. 2 that the addition of different high hydrogen content organics all produced very significant inhibition of the formation of heated coke from bio-oil. Therefore, the organic matter with high hydrogen content can be used as a hydrogen donor in the heating process of the bio-oil to effectively inhibit the generation of free radicals, so that the generation of coke in the heating process of the bio-oil is inhibited.

Example 2: (exploration of the Effect of the quality ratio of Bio-oil to free radical inhibitor Dihydrophenanthrene (DHP) on Coke yield in the pyrolysis reaction of Bio-oil)

Step 1): biological oil and radical inhibitor Dihydrophenanthrene (DHP) were mixed at a ratio of 1: 0. 1: 0.5, 1: 1. 1: 10, stirring fully, mixing uniformly to obtain a mixed sample, and adding the mixed sample into a quartz reactor;

step 2): respectively putting the quartz reactor added with the mixed sample obtained in the step 1) into a vertical furnace under the atmosphere of high-purity nitrogen (99.999%), wherein the bottom of the quartz reactor is positioned at the center of a hearth of the vertical furnace for heating, and the pyrolysis temperature is controlled to be 400 ℃;

step 3): repeating the steps 1) and 2), and controlling the reaction time to be 5min, 10min, 15min, 20min, 30min, 40min and 60min respectively;

step 4): after the reaction is finished, taking out the quartz reactor in the vertical furnace, and cooling in ice-water bath;

step 5): products after the pyrolysis reaction of the reactants in the three quartz reactors were separated using a mixed solution (methanol: dichloromethane ═ 1: 4 (volume ratio)) in which a solid product insoluble was called coke. The solids were dried using a vacuum oven and the coke was quantitatively analyzed using a subtraction method and the free radical content of the product was measured using an electron paramagnetic resonance spectrometer (EPR).

FIG. 3 shows the pyrolysis temperature of 400 ℃ and the ratio of bio-oil to free radical inhibitor Dihydrophenanthrene (DHP) in the ratio of 1: 0. 1: 0.5, 1: 1. 1: 10, the coke yield after the pyrolysis reaction of the bio-oil is compared with the result chart. As can be seen from FIG. 3, when the pyrolysis temperature is kept constant at 400 ℃ and no DHP is added into the bio-oil, the coke yield is between 38% and 41%, and the coking rate is higher. Changing the mixing ratio of the biological oil and the free radical inhibitor Dihydrophenanthrene (DHP), and when the mass ratio of the biological oil to the DHP is 1: when the coke rate is 0.5 percent, the coke rate is reduced by about 50 percent, and when the mass ratio of the bio-oil: DHP is 1: 1, the bio-oil pyrolysis process produces little coke as a solid product, while the amount of DHP added to the bio-oil continues to increase, for example: the mass ratio of DHP is 1: at 10, its ability to suppress coking no longer changes.

Example 3 (exploration of the relationship between pyrolysis temperature and DHP consumption)

Step 1): contacting a biological oil with a free radical inhibitor Dihydrophenanthrene (DHP) at a ratio of 1: 1, fully stirring and uniformly mixing to obtain a mixed sample, and then adding the mixed sample into a quartz reactor;

step 2): putting the quartz reactor added with the mixed sample obtained in the step 1) into a vertical furnace under the atmosphere of high-purity nitrogen (99.999%), wherein the bottom of the quartz reactor is positioned at the center of a hearth of the vertical furnace for heating, and the pyrolysis temperatures are respectively controlled to be 300 ℃, 400 ℃ and 600 ℃;

step 3): repeating the steps 1) and 2), and controlling the reaction time to be 5min, 10min, 15min, 20min, 30min, 40min and 60min respectively;

step 4): after the reaction is finished, taking out the quartz reactor in the vertical furnace, and cooling in ice-water bath;

step 5): products after the pyrolysis reaction of the reactants in the three quartz reactors were separated using a mixed solution (methanol: dichloromethane ═ 1: 4 (volume ratio)) in which a solid product insoluble was called coke. The solids were dried using a vacuum oven and the coke was quantitatively analyzed using a subtraction method and the free radical content of the product was measured using an electron paramagnetic resonance spectrometer (EPR).

FIG. 4 shows the decomposition amount of DHP in the pyrolysis reaction process, and the higher the decomposition amount of DHP in the heating reaction process of the bio-oil, the stronger the hydrogen supply capability of the bio-oil, so that the more the number of the trapped free radicals, the better the inhibition effect on coking. As can be seen from FIG. 4, the DHP consumption increases with increasing temperature, and the DHP is decomposed completely after heating at 600 ℃ for 30min, indicating that the DHP reacts completely with the radicals generated during the reaction under this condition, and the capture capacity of the DHP reaches a saturated state.

Although the embodiments of the present invention have been shown and described, it is understood that the above embodiments are illustrative and not restrictive, and that those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention and that the present invention also includes the modifications and changes.