阅读说明：本技术 一种热解油电化学温和高效加氢方法 (Electrochemical mild and efficient hydrogenation method for pyrolysis oil ) 是由 汪一 熊哲 邓伟 汪雪棚 徐俊 江龙 苏胜 胡松 向军 于 2021-01-20 设计创作，主要内容包括：本发明涉及一种热解油电化学温和高效加氢方法。本发明中虽然电化学电压超过析氢电压会促使部分电能用于电解热解油所含的水产生氢气和氧气,但是均匀溶解于热解油中的杂多酸可迅速与气相氢气结合并将气相氢气转化为“液相”活性氢,由此使得液相电化学反应体系中活性氢浓度得到显著提升,并进而显著降低热解油中有机组分在贵金属纳米颗粒催化剂上加氢所需的活化能；同时,本发明中将贵金属纳米颗粒催化剂均匀分散在热解油中,不仅有效的利用了贵金属催化加氢反应的能力,还有效突破了传统方式下热解油有机组分向电极迁移过程中的传质限制,更是将加氢反应扩展到了整个液相体系中,从而进一步加强了加氢反应速率。(The invention relates to an electrochemical mild and efficient hydrogenation method for pyrolysis oil. Although the electrochemical voltage exceeds the hydrogen evolution voltage, part of electric energy can be promoted to be used for electrolyzing water contained in the pyrolysis oil to generate hydrogen and oxygen, the heteropolyacid uniformly dissolved in the pyrolysis oil can be rapidly combined with gas-phase hydrogen and can convert the gas-phase hydrogen into 'liquid-phase' active hydrogen, so that the concentration of the active hydrogen in a liquid-phase electrochemical reaction system is remarkably improved, and the activation energy required by hydrogenation of organic components in the pyrolysis oil on a noble metal nanoparticle catalyst is remarkably reduced; meanwhile, the noble metal nanoparticle catalyst is uniformly dispersed in the pyrolysis oil, so that the capability of the noble metal for catalyzing the hydrogenation reaction is effectively utilized, the mass transfer limit of the organic component of the pyrolysis oil in the migration process to the electrode in the traditional mode is effectively broken through, and the hydrogenation reaction is expanded into the whole liquid phase system, so that the hydrogenation reaction rate is further enhanced.)

1. A pyrolysis oil electrochemical mild high-efficiency hydrogenation method is characterized by comprising the following steps:

1) adding water-soluble heteropoly acid and a noble metal nanoparticle catalyst into the pyrolysis oil to be hydrogenated, and uniformly mixing to dissolve the heteropoly acid in water contained in the pyrolysis oil and uniformly disperse the noble metal nanoparticles in the pyrolysis oil;

2) injecting the uniformly mixed pyrolysis oil obtained in the step 1) into a cathode chamber separated by a cation exchange membrane, then injecting an auxiliary solution into an anode chamber separated by the cation exchange membrane, and correspondingly arranging an anode electrode and a cathode electrode in the anode chamber and the cathode chamber respectively;

3) applying a voltage higher than the hydrogen evolution voltage of the pyrolysis oil to the pyrolysis oil through an electrode under stirring to enable the pyrolysis oil to generate electrochemical reaction;

4) and after the reaction is finished, performing centrifugal separation and filtration on the pyrolysis oil in the cathode chamber in the step 3), wherein filter residues are heteropoly acid and noble metal nano particles, and filtrate is the hydrogenation upgraded pyrolysis oil.

2. The electrochemical mild high-efficiency hydrogenation method for pyrolysis oil according to claim 1, wherein the addition amount of the heteropoly acid in the step 1) is 0.01-0.2mol per liter of pyrolysis oil.

3. The method for electrochemically and efficiently hydrogenating pyrolysis oil according to claim 1, wherein the noble metal nanoparticle catalyst is added in the step 1) in an amount of 0.05 to 0.2 wt% based on the mass of the pyrolysis oil.

4. The electrochemical mild and efficient hydrogenation method for pyrolysis oil according to claim 3, wherein the noble metal nanoparticle catalyst in step 1) is formed by loading noble metal on a porous active carrier.

5. The electrochemical mild and efficient hydrogenation process for pyrolysis oil of claim 4 wherein the noble metal is one of ruthenium, rhodium, palladium, osmium, iridium, and platinum.

6. The pyrolysis oil electrochemical temperature of claim 4And an efficient hydrogenation method, which is characterized in that the active carrier is active carbon, graphene and TiO₂One kind of (1).

7. The electrochemical mild and efficient hydrogenation method for pyrolysis oil according to claim 1, wherein the auxiliary solution in step 2) is an inorganic acid solution.

8. The method of claim 7, wherein the inorganic acid is one of sulfuric acid, hydrochloric acid, perchloric acid, and phosphoric acid solution.

9. The method for electrochemical mild highly efficient hydrogenation of pyrolysis oil as claimed in claim 1, wherein the time of the electrochemical reaction in step 3) is 0.5-4h, and the current density in the electrochemical reaction is 100-800mA cm^-2The stirring speed was 300-800 rpm.

10. The method for electrochemically and efficiently hydrogenating pyrolysis oil according to any one of claims 1 to 9, wherein the pyrolysis oil is formed by rapidly condensing volatile matters obtained after a thermal cracking reaction of carbon-containing solid organic matters at 800 ℃ under an inert atmosphere.

Technical Field

The invention relates to the technical field of organic solid waste treatment and application, in particular to a method for electrochemically and efficiently hydrogenating pyrolysis oil formed by pyrolyzing organic solid waste.

Background

Pyrolysis oil obtained by pyrolyzing solid organic matters such as coal and organic solid wastes (agricultural and forestry wastes, plastics, organic medical wastes and the like) is a promising liquid fuel and is expected to partially replace petroleum. Compared with petroleum, pyrolysis oil has low quality, mainly shows high oxygen content and water content, and causes low heat value and poor thermal stability, so that the pyrolysis oil cannot be successfully treated in the existing petrochemical refining equipment and needs further high-value utilization.

To upgrade pyrolysis oil for processing in existing petroleum refining facilities, pyrolysis oil typically requires hydro upgrading. The conventional pyrolysis oil hydrogenation upgrading process needs to be carried out at high temperature and high pressure, a catalyst is used, and the conventional pyrolysis oil hydrogenation upgrading process is prone to carbon deposition inactivation, coking and blockage of a reactor and other technical problems due to the fact that pyrolysis oil components are prone to coking when heated.

In order to solve the problems, in recent years, a process for upgrading the pyrolysis oil by electrochemical hydrogenation is provided, the electrochemical hydrogenation process is carried out at normal temperature and normal pressure, the problems of heating and coking of the pyrolysis oil and carbon deposition inactivation of a catalyst are greatly avoided, and the method is a pyrolysis oil hydrogenation upgrading technology with a very promising prospect. However, when the existing pyrolysis oil electrochemical hydrogenation upgrading process is applied in a large scale, the following problems still exist to be solved: 1. when the voltage/current is increased, a large amount of electric energy is used for hydrogen evolution reaction, so that the system efficiency is not high; 2. a large amount of moisture still exists in the upgraded pyrolysis oil product, and is difficult to remove, so that the pyrolysis oil is not beneficial to further utilization; 3. the hydrogenation process is mainly carried out on the surface of the electrode, and mass transfer resistance exists in the process of transferring pyrolysis oil components to the surface of the electrode, so that the increase of the reaction rate is limited.

In view of the above, there is a need to develop a high-efficiency bio-oil electrochemical hydrogenation method that can break through the reaction efficiency and rate limitation.

Disclosure of Invention

Aiming at the problems, the electrochemical mild and efficient hydrogenation method for the pyrolysis oil is provided, and aims to effectively improve the reaction rate and the Faraday efficiency of electrochemical hydrogenation through the double catalytic effect of coupling heteropoly acid and noble metal nanoparticles, so that the bio-oil is efficiently and rapidly hydrogenated under mild conditions, the oxygen content and the moisture content of the pyrolysis oil are obviously reduced, the thermal stability of the pyrolysis oil is improved, and the efficient, low-cost and large-scale utilization of the pyrolysis oil is finally facilitated.

The specific technical scheme is as follows:

a pyrolysis oil electrochemical mild and efficient hydrogenation method is characterized by comprising the following steps:

1) adding water-soluble heteropoly acid and a noble metal nanoparticle catalyst into the pyrolysis oil to be hydrogenated, and uniformly mixing to dissolve the heteropoly acid in water contained in the pyrolysis oil and uniformly disperse the noble metal nanoparticles in the pyrolysis oil;

2) injecting the uniformly mixed pyrolysis oil obtained in the step 1) into a cathode chamber separated by a cation exchange membrane, then injecting an auxiliary solution into an anode chamber separated by the cation exchange membrane, and correspondingly arranging an anode electrode and a cathode electrode in the anode chamber and the cathode chamber respectively;

3) applying a voltage higher than the hydrogen evolution voltage of the pyrolysis oil to the pyrolysis oil through an electrode under stirring to enable the pyrolysis oil to generate electrochemical reaction;

4) and after the reaction is finished, performing centrifugal separation and filtration on the pyrolysis oil in the cathode chamber in the step 3), wherein filter residues are heteropoly acid and noble metal nanoparticles, and filtrate is the hydrogenation upgraded pyrolysis oil.

The electrochemical mild high-efficiency hydrogenation method for the pyrolysis oil is also characterized in that the addition amount of the heteropoly acid in the step 1) is 0.01-0.2mol per liter of the pyrolysis oil.

The electrochemical mild and efficient hydrogenation method for pyrolysis oil is also characterized in that the noble metal nanoparticle catalyst is added in the step 1) in an amount of 0.05-0.2 wt% based on the weight of the pyrolysis oil.

The electrochemical mild and efficient hydrogenation method for pyrolysis oil also has the characteristic that the noble metal nanoparticle catalyst in the step 1) is formed by loading noble metal on a porous active carrier.

The electrochemical mild high-efficiency hydrogenation method for the pyrolysis oil is also characterized in that the noble metal is one of ruthenium, rhodium, palladium, osmium, iridium and platinum.

The electrochemical mild and efficient hydrogenation method for the pyrolysis oil is also characterized in that the active carrier is active carbon, graphene and TiO₂One kind of (1).

The electrochemical mild high-efficiency hydrogenation method for the pyrolysis oil also has the characteristic that the auxiliary solution in the step 2) is an inorganic acid solution.

The electrochemical mild high-efficiency hydrogenation method for the pyrolysis oil is also characterized in that the inorganic acid is one of sulfuric acid, hydrochloric acid, perchloric acid and phosphoric acid solution.

The electrochemical mild and efficient hydrogenation method for the pyrolysis oil is also characterized in that the electrochemical reaction time in the step 3) is 0.5-4h, and the current density in the electrochemical reaction is 100-800mA cm^-2The stirring speed was 300-800 rpm.

The electrochemical mild high-efficiency hydrogenation method for the pyrolysis oil has the characteristics that the pyrolysis oil is formed by quickly condensing volatile matters obtained after the carbon-containing solid organic matters undergo a thermal cracking reaction at 800 ℃ under the inert atmosphere at 200-.

In the invention, the pyrolysis oil is electrochemically hydrogenated at a voltage higher than the hydrogen evolution voltage of the pyrolysis oil, although the electrochemical voltage exceeding the hydrogen evolution voltage can cause part of the electric energy to be used for electrolysisThe water contained in the pyrolysis oil generates hydrogen and oxygen, but the heteropolyacid uniformly dissolved in the pyrolysis oil can rapidly combine with the gaseous phase hydrogen and combine the gaseous phase H₂The active hydrogen is converted into 'liquid phase' active hydrogen, so that the concentration of the active hydrogen in a liquid phase electrolysis reaction system is obviously improved, and the activation energy required by hydrogenation of organic components in the pyrolysis oil on a noble metal nanoparticle catalyst is obviously reduced; meanwhile, different from the traditional mode that only hydrogenation reaction occurs on an electrode, the noble metal nanoparticle catalyst is uniformly dispersed in the pyrolysis oil, so that the capability of the noble metal for catalyzing the hydrogenation reaction is effectively utilized, the mass transfer limit of organic components of the pyrolysis oil in the migration process to the electrode in the traditional mode is effectively broken through, and the hydrogenation reaction is expanded into the whole liquid phase system, so that the hydrogenation reaction rate is further enhanced. Therefore, the dual catalytic system of the heteropoly acid and the noble metal nanoparticle catalyst can remarkably promote hydrogen to transfer to the pyrolysis oil component through the noble metal nanoparticle catalyst, so that the pyrolysis oil is quickly hydrogenated, and proper hydrogen evolution does not reduce Faraday efficiency, and on the contrary, a proper water electrolysis process is beneficial to improving the concentration of active H in a liquid phase reaction system and the hydrogenation reaction rate; on the other hand, water in the pyrolysis oil is consumed through electrolysis, the moisture content in the target product oil is reduced, and the quality of the product is further improved.

According to the method, after the electrochemical reaction is finished, heteropolyacid can be separated out and crystallized due to the fact that water consumption is finished, and the viscosity of the hydrogenated and upgraded pyrolysis oil is remarkably reduced, so that the pyrolysis oil can be subjected to centrifugal separation.

The beneficial effect of above-mentioned scheme is:

1) the voltage and current density of the hydrogenation reaction in the invention are higher than those of the electrochemical hydrogenation reaction of the conventional pyrolysis oil, so that the hydrogenation rate is higher, and the water in the pyrolysis oil is consumed by increasing the voltage, thereby greatly reducing the moisture content of the upgraded oil;

2) hydrogen generated by water electrolysis during electrochemical hydrogenation is rapidly combined with heteropoly acid to form active hydrogen, so that hydrogen generated by hydrogen evolution due to the increase of reaction voltage can still hydrogenate organic components of pyrolysis oil by the method, and finally, the electrochemical parameters can be improved without reducing Faraday efficiency;

3) the active hydrogen needs low activation energy in the hydrogenation reaction process, and is more beneficial to the hydrogenation reaction on the noble metal nanoparticle catalyst. The noble metal nanoparticle catalyst distributed uniformly exists in the liquid phase hydrogenation system, so that the in-situ homogeneous hydrogenation of the pyrolysis oil can be realized approximately in a liquid phase form, the limitation that the reaction needs to be carried out on an electrode in the traditional electrochemical hydrogenation of the pyrolysis oil is broken through, and the mass transfer rate and the reaction efficiency are greatly improved.

Drawings

FIG. 1 is a graph of constant energy difference UV fluorescence spectra of pyrolysis oil in example 1 of the present invention;

FIG. 2 is a graph showing the content of characteristic components in pyrolysis oil before and after hydrogenation in example 1 of the present invention;

FIG. 3 is a graph showing the Faraday efficiency and current density in example 1 and comparative example 1 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.

Example 1

A pyrolysis oil electrochemical mild and efficient hydrogenation method comprises the following steps:

1) adding water-soluble heteropoly acid (in this embodiment, SiW is used as heteropoly acid)₁₂Heteropolyacids, measured per litre of pyrolysis oil0.01mol) and a noble metal nanoparticle catalyst (in the present invention, Pt nanoparticles are added, and the amount of the added Pt nanoparticles is 0.05 wt% based on the amount of the pyrolysis oil), and the mixture is uniformly mixed to dissolve heteropoly acid in the moisture contained in the pyrolysis oil and uniformly disperse the noble metal nanoparticles in the pyrolysis oil;

2) injecting the uniformly mixed pyrolysis oil obtained in the step 1) into a cathode chamber separated by a cation exchange membrane, then injecting an auxiliary solution (sulfuric acid in the embodiment) into an anode chamber separated by the cation exchange membrane, and correspondingly arranging an anode electrode and a cathode electrode in the anode chamber and the cathode chamber respectively;

3) applying a voltage higher than the hydrogen evolution voltage of the pyrolysis oil to the pyrolysis oil through an electrode under stirring to enable the pyrolysis oil to generate electrochemical reaction;

4) after the reaction is finished, performing centrifugal separation and filtration on the pyrolysis oil in the cathode chamber in the step 3), wherein filter residues are heteropoly acid and Pt nano particles (recycled), and filtrate is the hydrogenation upgraded pyrolysis oil;

wherein the electrochemical reaction time in the step 3) is 0.5h, and the current density in the electrochemical reaction is 100mA cm^-2The stirring speed was 300 rpm.

As shown in FIG. 1, the content of aromatic components in the pyrolysis oil is reduced after hydrogenation is carried out by using the hydrogenation method provided by the invention; further, as shown in fig. 2, the proportion of unsaturated components such as phenol and cyclohexanone in the pyrolysis oil is reduced, and the proportion of components such as cyclohexanol and cyclohexanol in the pyrolysis oil is increased after hydrogenation is performed by using the hydrogenation method, which indicates that hydrogenation reaction can be effectively performed on the pyrolysis oil by using the hydrogenation method provided by the invention.

As shown in FIG. 3, SiW is used₁₂And Pt nanoparticles even when the current density was increased to 600mA cm^-2The Faraday efficiency in the system is still higher, which indicates that SiW₁₂And the Pt nano-particle dual-catalytic system can obviously improve the reaction rate by improving the electrochemical parameters without reducing the Faraday efficiency.

According to the invention, the moisture content of the pyrolysis oil before and after electrochemical hydrogenation is detected by using a Karl Fischer titration method, and the moisture content in the pyrolysis oil is reduced from 26.00 wt% before electrolysis to 5.23 wt% after electrolysis, which shows that the moisture content in the product oil after hydrogenation by using the hydrogenation method provided by the invention is obviously reduced.

Example 2

A pyrolysis oil electrochemical mild and efficient hydrogenation method comprises the following steps:

1) adding water-soluble heteropoly acid (in this embodiment, SiW is used as heteropoly acid)₁₂The addition of heteropoly acid is 0.1mol per liter of pyrolysis oil) and noble metal nanoparticle catalyst (Pt nanoparticles in the invention, and the addition of Pt nanoparticles is 0.12 wt% based on the pyrolysis oil) are uniformly mixed, so that heteropoly acid is dissolved in the moisture contained in the pyrolysis oil, and noble metal nanoparticles are uniformly dispersed in the pyrolysis oil;

2) injecting the uniformly mixed pyrolysis oil obtained in the step 1) into a cathode chamber separated by a cation exchange membrane, then injecting an auxiliary solution (sulfuric acid in the embodiment) into an anode chamber separated by the cation exchange membrane, and correspondingly arranging an anode electrode and a cathode electrode in the anode chamber and the cathode chamber respectively;

3) applying a voltage higher than the hydrogen evolution voltage of the pyrolysis oil to the pyrolysis oil through an electrode under stirring to enable the pyrolysis oil to generate electrochemical reaction;

4) after the reaction is finished, centrifugally separating and filtering the pyrolysis oil in the cathode chamber in the step 3), wherein filter residues are heteropoly acid and Pt nano particles (recycled), and filtrate is the hydrogenated and upgraded pyrolysis oil

Wherein the electrochemical reaction time in the step 3) is 2.4h, and the current density in the electrochemical reaction is 510mA cm^-2The stirring speed was 560 rpm.

Example 3

A pyrolysis oil electrochemical mild and efficient hydrogenation method comprises the following steps:

1) adding water-soluble heteropoly acid (in this embodiment, SiW is used as heteropoly acid)₁₂Heteropoly acid in an amount of 0.2mol per liter of pyrolysis oil) and a noble metal nanoparticle catalyst (in the present invention, Pt nanoparticles in an amount of 0.2 wt% based on the amount of pyrolysis oil) were mixedUniformly dissolving the heteropoly acid in the moisture contained in the pyrolysis oil, and uniformly dispersing the noble metal nano particles in the pyrolysis oil;

2) injecting the uniformly mixed pyrolysis oil obtained in the step 1) into a cathode chamber separated by a cation exchange membrane, then injecting an auxiliary solution (perchloric acid in the embodiment) into an anode chamber separated by the cation exchange membrane, and correspondingly arranging an anode electrode and a cathode electrode in the anode chamber and the cathode chamber respectively;

3) applying a voltage higher than the hydrogen evolution voltage of the pyrolysis oil to the pyrolysis oil through an electrode under stirring to enable the pyrolysis oil to generate electrochemical reaction;

4) after the reaction is finished, performing centrifugal separation and filtration on the pyrolysis oil in the cathode chamber in the step 3), wherein filter residues are heteropoly acid and Pt nano particles (recycled), and filtrate is the hydrogenation upgraded pyrolysis oil;

wherein the electrochemical reaction time in the step 3) is 4h, and the current density in the electrochemical reaction is 800mA cm^-2The stirring speed was 800 rpm.

Comparative example 1

The hydrogenation process in this comparative example is essentially the same as in example 1, except that no water-soluble heteropolyacid and no Pt nanoparticles are added to the pyrolysis oil to be hydrogenated in step 1) of this comparative example.

As can be seen from FIG. 3, SiW was not used in increasing the current density of the electrochemical hydrogenation process₁₂And the system faradaic efficiency was significantly decreased in the case of Pt nanoparticles, and thus it was found that the rate of the hydrogenation reaction in the present comparative example was significantly lower than that in example 1 of the present invention.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.