Method for regulating active sites of co / c catalyst adapted for microwave reforming of exposed biomass tar and use thereof

Abstract

A Co / C catalyst for biomass tar microwave reforming, a preparation method therefor, and a use thereof. The preparation method for a Co / C catalyst comprises the following steps: mixing 2-methylimidazole, cobalt nitrate, and an organic coordinating compound and reacting to obtain a modified ZIF-67 suspension; performing solid-liquid separation to obtain modified ZIF-67 nanoparticles; and heat-treating the modified ZIF-67 nanoparticles to obtain a modified Co / C catalyst. By reasonably selecting the organic coordinating compound, the strength of the metal–support interaction during catalyst formation can be optimized, the exposed active sites on the catalyst surface can be regulated, and the reaction activity and stability of the catalyst in the catalytic reforming of biomass tar can be effectively improved.

Description

A method for regulating the active sites of biomass tar microwave reforming adapted Co / C catalysts and its application Technical Field

[0001] This invention relates to the field of clean biomass energy production, and more particularly to the field of biomass gasification tar catalytic conversion technology, especially to a method for regulating the active sites of microwave reforming-adapted Co / C catalysts for biomass tar and its application. Background Technology

[0002] Biomass energy is an important renewable energy source that can directly replace fossil fuels, and its share in energy consumption is increasing year by year. Biomass gasification is a technology that efficiently converts biomass into renewable gasified fuel, possessing significant economic value and development potential. However, tar formation is a bottleneck in biomass gasification, not only reducing gasification efficiency but also affecting the downstream applications of the gasified fuel. Therefore, the development of efficient tar removal technology is crucial for the widespread adoption of biomass gasification.

[0003] Microwave catalytic reforming of tar is considered a key technology for solving the tar problem. It can lower the energy barrier of chemical reactions under the microwave effect, promote the conversion of tar into chemical reactions, and reduce the required reaction temperature. Simultaneously, the reformed gas produced can improve the quality of biomass fuel gas. However, the catalyst still faces the problem of easy carbon deposition and deactivation during microwave catalytic reforming. Research on applying inexpensive biochar catalysts to this technology has encountered problems such as the difficulty in directionally controlling the microstructure of biochar and the degree of exposure of active metal sites, requiring further optimization of the catalyst.

[0004] Summary of the Invention

[0005] The purpose of this invention is to provide a method for regulating the active sites of a Co / C catalyst adapted for microwave reforming of biomass tar and its application, thereby solving the aforementioned problems in the background art. This invention uses an organic coordination compound-modified ZIF-67 as a sacrificial template for pyrolysis to prepare a Co / C catalyst, providing a method for preparing a highly efficient catalyst for microwave catalytic reforming of tar. By rationally selecting the organic coordination compound, the metal-support interaction strength during catalyst formation can be optimized, the exposed active sites on the catalyst surface can be regulated, and the reaction activity and stability of the catalyst in the catalytic reforming process of biomass tar can be effectively improved.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions of this invention is to provide a method for preparing a Co / C catalyst for catalytic reforming of tar, comprising the following steps:

[0008] 2-methylimidazole, cobalt nitrate and an organic coordination compound were mixed and reacted to obtain a modified ZIF-67 suspension; solid-liquid separation was performed to obtain modified ZIF-67 nanoparticles.

[0009] The modified ZIF-67 nanoparticles were subjected to heat treatment to obtain a modified Co / C catalyst.

[0010] Preferably, the organic coordination compound is hexadecyltrimethylammonium bromide or ascorbic acid.

[0011] Preferably, the molar ratio of 2-methylimidazole to cobalt nitrate is 8:1; and the molar ratio of the organic coordination compound to cobalt nitrate is 1:8 to 12.

[0012] Preferably, the heat treatment temperature is 600–800°C, the heating rate is 1–2°C / min, the residence time is 2–3 hours, and the atmosphere is a protective atmosphere.

[0013] Preferably, the heat treatment process further includes a grinding step; the grinding is performed until the material passes through a 40-80 mesh sieve.

[0014] The second technical solution of the present invention provides a Co / C catalyst for catalytic reforming of tar obtained according to the above preparation method.

[0015] The third technical solution of the present invention provides an application of the above-mentioned Co / C catalyst for tar catalytic reforming in the field of microwave catalytic reforming of tar.

[0016] Fourth technical solution of the present invention: A method for microwave catalytic steam reforming of tar, comprising the following steps:

[0017] The above-mentioned Co / C catalyst for catalytic reforming of tar is placed in a microwave reaction chamber to form a catalyst bed;

[0018] Water and tar are preheated by a steam generator and then introduced into the microwave reaction cavity along with carrier gas to carry out a steam reforming reaction under microwave heating conditions.

[0019] Preferably, the water-to-carbon ratio of the water and tar is 2:1, the preheating temperature is 150°C, and the carrier gas flow rate is 50-100 mL / min.

[0020] Preferably, the conditions for the steam reforming reaction are: a heating temperature of 400–500°C and a tar gas hourly space velocity of 15,000–20,000 mL / (h·g). cat ).

[0021] The molar ratio of cobalt nitrate to 2-methylimidazole is 1:8, which can provide a high concentration of ligands and is conducive to the nucleation of ZIF-67 crystals. The molar ratio of cobalt nitrate to organic coordination compounds is 8 to 12:1, which can partially control the coordination strength on the crystal surface and facilitate the exposure of active sites by subsequent heat treatment.

[0022] The beneficial technical effects of the present invention are as follows:

[0023] This invention provides a method for preparing a highly efficient catalyst for microwave catalytic reforming of biomass tar by using organic coordination compounds to modify ZIF-67 as a sacrificial template for pyrolysis to prepare a Co / C catalyst. By rationally selecting the organic coordination compound, the coordination competition between Co and 2-methylimidazole in ZIF-67 can be inhibited, partially altering the crystal coordination state. This optimizes the metal-support interaction strength during catalyst formation, regulates the exposure of active sites on the catalyst surface, and effectively enhances the catalyst's reactivity and stability in the catalytic reforming of biomass tar.

[0024] The modified Co / C-CT catalyst of this invention exhibits significantly enhanced reducibility and alkalinity, and can increase the toluene conversion rate from 73.67% to 96.66% in the microwave steam reforming of tar at 400℃.

[0025] The modified Co / C-CT catalyst of this invention also significantly enhances the catalyst's lifespan. In a stability test at 500°C for 6 hours, the toluene conversion rate only decreased from 99.67% to 94.04%, which is 3.63 times the lifespan of the unmodified Co / C.

[0026] The cobalt metal nanoparticles exposed on the surface of the catalyst of the present invention exist as oxygen carriers in the form of CoO(111) during the reaction process. They can combine with microwave-activated polar molecules to generate active free radicals in the form of chemical chain steam reforming reaction, which greatly reduces the carbon deposition of the catalyst during the reaction process, thereby maintaining the high activity of the catalyst and playing a decisive role in the catalytic effect of the tar steam reforming process. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 shows the H2-TPR results of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3.

[0029] Figure 2 shows the CO2-TPD results of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3.

[0030] Figure 3 shows the toluene conversion rates of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 at different temperatures.

[0031] Figure 4 shows the changes in toluene conversion rate of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 during stability testing.

[0032] Figure 5 shows HRTEM images of the Co / C catalyst prepared in Example 1 before and after the stability test. (a) shows the image before the reaction, and (b) shows the image after the reaction.

[0033] Figure 6 shows XPS images of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 before and after the stability test reaction. (a) shows the reaction before the reaction, and (b) shows the reaction after the reaction. Detailed Implementation

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0035] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0036] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0037] The terms “comprising,” “including,” “having,” “containing,” etc., used in this invention are all open-ended terms, meaning that they include but are not limited to.

[0038] This invention discloses a method for preparing a Co / C catalyst for catalytic reforming of tar, comprising the following steps:

[0039] Cobalt nitrate hexahydrate was dissolved in methanol by stirring to obtain solution A; 2-methylimidazole was dissolved in methanol by stirring to obtain solution B; the organic coordination compound was dissolved in deionized water by stirring to obtain solution C; solutions B and C were mixed to obtain a ligand solution, which was ultrasonically dispersed for 0.5 h, and then solution A was added dropwise to obtain a precursor solution (the molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole was 1:8, the molar ratio of cobalt nitrate hexahydrate to the organic coordination compound was 8:1, and the volume ratio of solutions A, B and C was 3:3:2). The mixture was stirred continuously for 8 h, and after standing to precipitate, the lower layer of suspension was taken out, and the solid and liquid were separated. The obtained precipitate was placed in an oven and dried at 60 °C for 12 h to obtain ZIF-67 nanoparticles.

[0040] ZIF-67 nanoparticles were placed inside a quartz boat, which was then placed in a tube furnace for heat treatment under a nitrogen atmosphere. During the heat treatment, the nitrogen flow rate was 200 mL / min, the reaction temperature was 800℃, the heating rate was 2℃ / min, and the residence time was 2 h. Before heat treatment, the furnace atmosphere was purged with nitrogen for 0.5 h to replace the nitrogen atmosphere. After heat treatment, a black powder product was obtained, which was then ground to pass through a 40–80 mesh sieve, yielding the Co / C catalyst (denoted as Co / C-CT).

[0041] The ligand solution needs to be pretreated by ultrasonic dispersion for 0.5 h to enhance the dispersion of the ligand in the solvent and improve the uniformity of ZIF-67 crystal nucleation. Continuous stirring of the precursor solution can ensure the stability of ZIF-67 crystal nucleation.

[0042] Preferably, the solid-liquid separation method is as follows: the modified ZIF-67 suspension is centrifuged at a speed of ≥6000 rpm, methanol or ethanol is added to the solid phase component for at least 3 shaking washes, and then the solvent is removed by centrifugation.

[0043] The precipitate is shaken and washed to remove excess metal salts, ensuring that the formation of Co / C in the subsequent pyrolysis process is not affected. The centrifugation speed needs to be no less than 6000 rpm to reduce precipitate loss during centrifugal sedimentation.

[0044] A heating rate of 2℃ / min is beneficial for the stable precipitation of volatiles during heat treatment and reduces the sintering of metal nanoparticles. Too fast or too slow a rate will destroy this effect. The heating temperature is 800℃, and the residence time is 2 hours to improve the degree of carbon graphitization of the support and enhance the stability of the catalyst during catalytic reforming.

[0045] The present invention specifies a grinding particle size of 40-80 mesh, which can ensure uniform particle size and improve the uniformity of plasma generation in the microwave field during microwave heating.

[0046] The aforementioned Co / C catalyst was placed on a porous quartz plate in a microwave-controlled quartz tube reactor to form a catalytic bed. 1000 ppm toluene / nitrogen cylinder gas was introduced into the reaction pipeline at a rate of 50 mL / min as the reactant. The injection water volume was controlled by a micro-injection pump, adjusting the water-to-carbon ratio (S / C) to 2. The injected water was heated to 150°C by a steam generator and vaporized, then mixed with the cylinder gas carrier gas before passing through the catalytic bed. The reaction temperature of the catalytic bed was controlled at 400-500°C by a microwave control system. The reaction temperature was fed back to the intelligent control system by a K-type thermocouple. The gas hourly space velocity (HSV) of the tar was 15000-20000 mL / (h·g). cat ).

[0047] This invention specifies an S / C ratio of 2 to ensure that toluene is fully reformed. The preheating and holding temperature is 150°C to prevent condensation of toluene and vapor before they pass through the catalytic bed. The carrier gas flow rate is 50 mL / min to ensure uniform mixing of the reactant gases before they enter the catalytic bed.

[0048] Maintaining the reaction temperature at 400℃ achieves a high tar conversion rate (>90%). Because the Co / C catalyst of this invention has extremely high efficiency for microwave steam reforming of tar, a high gas hourly space velocity can be selected.

[0049] All raw materials used in the following embodiments and comparative examples of the present invention are commercially available products.

[0050] Example 1

[0051] A method for preparing a Co / C catalyst for catalytic reforming of tar, comprising the following steps:

[0052] Cobalt nitrate hexahydrate was dissolved in methanol by stirring to obtain solution A; 2-methylimidazole was dissolved in methanol by stirring to obtain solution B; an organic coordination compound (ascorbic acid) was dissolved in deionized water by stirring to obtain solution C; solutions B and C were mixed to obtain a ligand solution, which was ultrasonically dispersed for 0.5 h, and then solution A was added dropwise to obtain a precursor solution (the molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole was 1:8, the molar ratio of cobalt nitrate hexahydrate to the organic coordination compound was 8:1, and the volume ratio of solutions A, B and C was 3:3:2). The mixture was stirred continuously for 8 h, and after settling, the lower suspension was taken out and centrifuged at a speed of ≥6000 rpm. Then, methanol was added to the solid phase component for three shaking washes, and methanol was removed by centrifugation. The resulting precipitate was dried in an oven at 60 °C for 12 h to obtain ZIF-67 nanoparticles.

[0053] ZIF-67 nanoparticles were placed inside a quartz boat, which was then placed in a tube furnace for heat treatment under a nitrogen atmosphere. During the heat treatment, the nitrogen flow rate was 200 mL / min, the reaction temperature was 800℃, the heating rate was 2℃ / min, and the residence time was 2 h. Before heat treatment, the furnace atmosphere was purged with nitrogen for 0.5 h to replace the nitrogen atmosphere. After heat treatment, a black powder product was obtained, which was then ground to pass through a 40-mesh sieve, yielding the Co / C catalyst (denoted as Co / C-CT).

[0054] Example 2

[0055] The only difference from Example 1 is that ascorbic acid is replaced with an equimolar amount of hexadecyltrimethylammonium bromide, and the resulting product is denoted as Co / C-AA.

[0056] Comparative Example 1

[0057] The only difference from Example 1 is that ascorbic acid is replaced with an equimolar amount of citric acid, and the resulting product is denoted as Co / C-CA.

[0058] Comparative Example 2

[0059] The only difference from Example 1 is that ascorbic acid is replaced with an equimolar amount of disodium ethylenediaminetetraacetate, and the resulting product is denoted as Co / C-EA.

[0060] Comparative Example 3

[0061] The only difference from Example 1 is that the addition of ascorbic acid is omitted, and an equal volume of deionized water is directly mixed with solution B for subsequent preparation steps. The resulting product is denoted as Co / C.

[0062] Figure 1 shows the H2-TPR results of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3.

[0063] As shown in Figure 1, all curves can be divided into four parts, including the Co content on the catalyst surface. 0 The figures show an α peak (around 150℃) caused by the reduction of CoO formed by the reaction with air, a β peak (around 300℃) from the reduction of bulk Co3O4, a γ peak (around 380℃) from the reduction of CoO, and a δ peak (around 550℃) from the gasification of amorphous carbon and skeletal carbon. In Figure 1, the modification with AA and CT significantly enhanced the intensity of the reduction peaks of bulk Co3O4 and CoO, indicating that the addition of AA and CT weakened the metal-support interaction to a greater extent, exposing more cobalt nanoparticles and thus improving the reducibility of the catalyst, which is beneficial for steam reforming. All groups with added organic coordination compounds showed enhanced δ peak intensity, indicating improved reactivity of the carbon support.

[0064] Figure 2 shows the CO2-TPD results of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3.

[0065] In Figure 2, the peaks at approximately 100℃, 300℃, and 500℃ represent weakly basic, moderately basic, and strongly basic peaks, respectively. The peak intensities of Co / C-AA and Co / C-CT are greater than those of other catalysts, indicating that the exposure of cobalt nanoparticles enhances the basicity of the catalyst and can promote the steam reforming reaction of toluene.

[0066] Example 1

[0067] Microwave catalytic steam reforming experiments were conducted using toluene as a model compound for biomass gasification of tar. The specific operating steps are as follows: The Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 were placed on a porous quartz plate in a quartz tube reactor within a microwave cavity to form a catalytic bed. 1000 ppm toluene / nitrogen cylinder gas was introduced into the reaction pipeline at a rate of 50 mL / min as the reactant. The injection water volume was controlled by a micro-injection pump, adjusting the water-to-carbon ratio (S / C) to 2. The injected water was heated to 150°C by a steam generator and vaporized, then mixed with the cylinder gas carrier gas before passing through the catalytic bed. The reaction temperature of the catalytic bed was controlled at 400 and 500°C by a microwave control system. The reaction temperature was fed back to the intelligent control system by a K-type thermocouple. The gas hourly space velocity (HSV) of the tar was 20000 mL / (h·g). cat The gaseous products of the reaction and the unreacted toluene are directly introduced into the gas detection system along with the gas flow. The toluene conversion rate R is calculated using the following formula:

[0068] Figure 3 shows the toluene conversion rates of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 at different temperatures.

[0069] As shown in Figure 3, the Co / C-AA and Co / C-CT groups exhibited significantly higher toluene conversion efficiencies compared to the other groups. At 400℃, the toluene conversion rates of Co / C-AA and Co / C-CT increased from 73.67% for Co / C to 92.21% and 96.66%, respectively.

[0070] Example 2

[0071] The stability of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 was tested. The conditions differed from those in Example 1 only in that the catalytic bed reaction temperature was 500℃, the reaction time was 6 h, and samples were taken every 15 minutes to detect the concentration of each component in the gaseous products. The used catalyst was collected after the reaction for characterization testing. The test results are shown in Figures 4-6.

[0072] Figure 4 shows the changes in toluene conversion rate of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 during stability testing.

[0073] As shown in Figure 4, the Co / C-AA and Co / C-CT catalysts, which exhibited higher reactivity, demonstrated better stability. After the test, the toluene conversion rate of Co / C-CT slowly decreased from 99.67% to 94.04%, while that of the Co / C-AA group slowly decreased from 100% to 89.09%. The Co / C catalyst showed the fastest deactivation rate, with the conversion rate decreasing from 95.91% to 75.46%. The Co / C-EA and Co / C-CA groups performed slightly better than the Co / C group, with final conversion rates of 83.01% and 79.9%, respectively. These results indicate that the preferred organic coordination compounds of this invention can enhance the stability of the catalyst by regulating the Co / C process.

[0074] Figure 5 shows HRTEM images of the Co / C catalyst prepared in Example 1 before and after the stability test. (a) shows the image before the reaction, and (b) shows the image after the reaction.

[0075] Figure 5(a) shows that after modification by organic coordination compounds during catalyst preparation, some cobalt metal nanoparticles on the catalyst surface are exposed outside the graphite carbon layer during heat treatment. In Figure 5(b), it is observed that the exposed cobalt metal nanoparticles exist in the form of CoO(111) during the reaction.

[0076] Figure 6 shows XPS images of the Co / C catalysts prepared in Examples 1-2 and Comparative Examples 1-3 before and after the stability test reaction. (a) shows the reaction before the reaction, and (b) shows the reaction after the reaction.

[0077] In Figure 6, Co / CP, Co / C-AA-P, Co / C-CT-P, Co / C-EA-P, and Co / C-CA-P represent the treated Comparative Example 3, Example 1, Example 2, Comparative Example 2, and Comparative Example 1, respectively.

[0078] Figure 6 shows that three peaks are separated at binding energies of 529.4, 531.4, and 533.3 eV, corresponding to lattice oxygen (O₂) and lattice oxygen (O₂). l ), oxygen vacancy adsorption of oxygen (O) ad ) and adsorbed water oxygen (O) w O in the catalyst before the reaction. ad As the main component, all catalysts after the reaction showed O after stability testing. w Signal. O after stability testing of Co / C-AA-P and Co / C-CT-P lThe signal is prominent, indicating that the content of cobalt oxide on the catalyst surface increases during the reaction process. This corresponds to the HRTEM results, which show that the exposed cobalt nanoparticles are composed of CoO(111).

[0079] Combining the catalyst testing and characterization results, the performance advantages of the catalyst of this invention can be seen. This is mainly because the addition of organic coordination compounds successfully weakens the metal-support interaction of the catalyst to a certain extent, increases the exposure of cobalt nanoparticles on the catalyst surface, and enhances the reducing and basic properties of the catalyst. During the reaction, the carbon gasification rate of unexposed metal active sites is lower than that of carbon deposition, leading to pyrolysis coke deposition, further forming encapsulated coke, reducing catalytic activity, and the accumulated pyrolysis coke can also block micropores, causing catalyst deactivation. For exposed sites, the metal nanoparticles are oxidized to CoO, and then act as an oxygen support to promote tar reforming reaction through chemical ring steam reforming. Therefore, during the reaction, the exposed metal active sites in the product of this invention can keep the catalyst in an unencapsulated state as much as possible, maintaining high reactivity, that is, forming strong catalyst stability.

[0080] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a Co / C catalyst for catalytic reforming of tar, characterized by, Includes the following steps: 2-methylimidazole, cobalt nitrate and an organic coordination compound were mixed and reacted to obtain a modified ZIF-67 suspension; solid-liquid separation was performed to obtain modified ZIF-67 nanoparticles. The modified ZIF-67 nanoparticles were subjected to heat treatment to obtain a modified Co / C catalyst.

2. The production method according to claim 1, characterized by, The organic coordination compound is hexadecyltrimethylammonium bromide or ascorbic acid.

3. The preparation method according to claim 1, characterized in that, The molar ratio of 2-methylimidazole to cobalt nitrate is 8:1; the molar ratio of the organic coordination compound to cobalt nitrate is 1:8 to 12.

4. The method of claim 1, wherein, The heat treatment temperature is 600–800℃, the heating rate is 1–2℃ / min, the residence time is 2–3h, and the atmosphere is a protective atmosphere.

5. The preparation method according to claim 1, characterized in that, The heat treatment process includes a grinding step; the grinding is performed until the material passes through a 40-80 mesh sieve.

6. A Co / C catalyst for catalytic reforming of tar obtained by the preparation method according to any one of claims 1-5.

7. The application of the Co / C catalyst for catalytic reforming of tar as described in claim 6 in the field of microwave catalytic reforming of tar.

8. A method of tar microwave catalytic steam reforming, characterized by, Includes the following steps: The Co / C catalyst for catalytic reforming of tar as described in claim 6 is placed in a microwave reaction chamber to form a catalytic bed; Water and tar are preheated by a steam generator and then introduced into the microwave reaction cavity along with carrier gas to carry out a steam reforming reaction under microwave heating conditions.

9. The method of claim 8, wherein, The water-to-carbon ratio of the water and tar is 2:1, the preheating temperature is 150℃, and the carrier gas flow rate is 50-100mL / min.

10. The method of claim 8, wherein, The conditions of the steam reforming reaction are: heating temperature of 400-500℃, gas hourly space velocity of the tar of 15000-20000 mL / (h.g cat ).

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