KR100986241B1 - Catalytic for steam reforming of tar produced from biomass gasification process and method of steam reforming of tar using the same - Google Patents

Abstract

Disclosed are a catalyst for steam reforming of tar that can increase the decomposition activity and stability of tar and the hydrogen production in the steam reforming reaction of tar generated during the biomass gasification process, and a method for steam reforming of tar using the same. The tar steam reforming catalyst is used in the tar steam reforming process generated during the biomass gasification process, and includes a support including cerium oxide and zirconium oxide, and nickel supported in the support. As described above, when performing a steam reforming process of generating a synthesis gas of hydrogen and carbon monoxide using a nickel catalyst using a mixture of cerium oxide and zirconium oxide (Ni / Al ₂ O ₃ / SiO ₂ ) Compared with tar, the decomposition activity of tar is excellent, and even if time passes, the activity of catalyst is very small and can be used for a long time without replacement. Accordingly, the decomposition efficiency due to the catalytic steam reforming reaction of tar generated in the biomass gasification process can be increased.

Description

Catalyst for steam reforming of tar and steam reforming method using tar {catalytic for steam reforming of tar produced from biomass gasification process and method of steam reforming of tar using the same}

The present invention relates to a steam reforming catalyst of tar and a method of steam reforming tar using the same. More specifically, the catalyst for reforming tar of steam that can be most efficiently decomposed into hydrogen, carbon monoxide and carbon dioxide by catalytic steam reforming of the tar generated during the biomass gasification process, and the method of reforming tar using the same It is about.

In the biomass gasification process, a high tar content in the generated gas is a problem. In the biomass gasification process, when a fluidized bed gasifier is used, tar of about 5 to 75 g / Nm ³ is generated, and the tar content exceeds the maximum value allowed for operation of a gas turbine or a gas engine. Therefore, a process for minimizing the content of tar in the generated gas is required, and in general, a method for converting tar into a synthetic gas containing hydrogen and carbon monoxide is used. Examples of such methods may include catalytic steam reforming, thermal catalytic reforming, catalytic partial oxidation and noncatalytic partial oxidation. At this time, the tar is converted into a synthetic gas and used as a feed material for synthesizing clean transport materials such as gas fuel, methanol, DME (dimethyl ether) and Fischer-Tropsch oil for power generation.

In general, catalytic steam reforming is used as the most efficient method for decomposing tar generated in the biomass gasification process. The main components of tar generated through the biomass gasification process include about 66% of monocyclic aromatic hydrocarbons including benzene, toluene, and about 22% of polycyclic aromatic hydrocarbons such as naphthalene. Therefore, the catalytic steam reforming has been studied using benzene, toluene and naphthalene, which are the main components of tar, and the catalysts used so far include natural minerals such as olivine, dolomite, or silicon oxide ( And a nickel catalyst using SiO ₂ ) or aluminum oxide (Al ₂ O ₃ ) or the like as a support.

The catalytic steam reforming process converts an aromatic hydrocarbon containing gas into hydrogen, carbon monoxide by reacting with steam under a catalyst at a high temperature of about 700 to 1000 ° C. At this time, a portion of the carbon monoxide is converted to carbon dioxide by a gas shift reaction with hydrogen of steam at a low temperature. This process is typically carried out by mixing aromatic hydrocarbon containing gas and water vapor and then injecting it into a preheated reactor in which the decomposition, oxidation and reassembly of the hydrocarbon takes place.

However, the use of natural mineral catalysts, although useful for the steam reforming reaction of tar, has been suggested as problems such as low activity, low strength, deterioration of stability by melting point. In addition, the nickel catalyst using the commercially available silicon oxide (SiO ₂ ) or aluminum oxide (Al ₂ O ₃ ), etc. as a support shows a high activity but has the disadvantage that the deactivation of the catalyst by carbon deposition proceeds quickly.

Accordingly, in order to solve the problem of the catalyst used in the steam reforming reaction, not only nickel (Ni) catalyst but also platinum (Pt), rhodium (Rh), ruthenium (Ru), palladium (Pd), nickel (Ni) Catalysts using such transition metals have been prepared. Catalyst technology using rhodium (Rh) used in the decomposition of tar in the biomass gasification process is disclosed in US Patent Publication No. 2003-0115800 issued to Tomishige Keichi. In this case, the rhodium catalyst disclosed in US Patent Publication No. 2003-0115800 is a catalyst (Rh / CeO ₂ / SiO ₂ ) supporting rhodium (Rh) using cerium oxide (CeO ₂ ) and silicon oxide (SiO ₂ ) as a support. In the steam reforming of tar, the results were very good in terms of activity, stability and selectivity for hydrogen production. However, rhodium (Rh) used in the rhodium catalyst has a high cost burden as an expensive noble metal element, and is very low in effectiveness to be used as a catalyst for tar steam reforming in the biomass gasification process.

One object of the present invention for solving the above problems is to provide a tar steam reforming catalyst that can increase the activity and stability and hydrogen production in the steam reforming reaction of tar generated in the biomass gasification process.

Another object of the present invention is to provide a method for steam reforming of tar using a catalyst that can increase the decomposition activity, stability and hydrogen production of the tar.

The tar steam reforming catalyst according to an embodiment of the present invention for achieving the above object is used in a steam reforming process of tar generated during a biomass gasification process, and includes a support including cerium oxide and zirconium oxide. And nickel supported in the support.

As an example, the support including cerium oxide and zirconium oxide is 25 To 75% by weight of cerium oxide. The catalyst may comprise nickel in the range of 5 to 15% by weight.

According to another aspect of the present invention, a method for steam reforming of tar provides a reactor including a support including cerium oxide and zirconium oxide and a catalyst including nickel supported in the support. Steam is mixed with tar generated during the biomass gasification process to produce a mixture. The mixture is fed to a reactor to decompose the tar in the presence of the catalyst.

As an example, the support including cerium oxide and zirconium oxide is 25 To 75% by weight of cerium oxide, the catalyst may comprise the nickel in the range of 5 to 15% by weight.

At this time, the process of decomposing the tar may be carried out at a temperature of 500 to 750 ℃.

According to the present invention, in the catalytic steam reforming process of tar generated in the biomass gasification process having the above-described configuration, cerium oxide (CeO ₂₎ having high activity and less activity decrease with time generated in the biomass gasification process is generated. ) And a zirconium oxide (ZrO ₂ ) can be converted into a synthesis gas containing hydrogen and carbon monoxide using a catalyst supported on nickel.

According to the tar steam reforming catalyst generated in the biomass gasification process of the present invention, the catalyst includes a support including cerium oxide (CeO ₂ ) and zirconium oxide (ZrO ₂ ), and nickel supported in the support. It includes.

Nickel catalysts used in the steam reforming process of tar have better activation of the decomposition process of tar than conventional commercially available nickel catalysts (Ni / Al ₂ O ₃ / SiO ₂ ), and the catalyst activity decreases over time. It is very small and can be used for a long time without replacement. Therefore, the decomposition efficiency by the catalytic steam reforming reaction of tar generated in the biomass gasification process can be increased.

Hereinafter, the tar steam reforming catalyst generated in the biomass gasification process according to the embodiments of the present invention and the steam reforming method of tar using the same will be described in detail with reference to the accompanying drawings. The present invention is not limited thereto, and one of ordinary skill in the art may implement the present invention in various other forms without departing from the technical spirit of the present invention. In the accompanying drawings, the dimensions of each component is shown in an enlarged scale than actual for clarity of the invention.

Specific structural to functional descriptions are merely illustrated for the purpose of describing the embodiments of the present invention, and the embodiments of the present invention may be embodied in various forms and include all modifications and equivalents included in the spirit and scope of the present invention. It is to be understood to include to substitutes.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "having" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof that is practiced, and that one or more other features or numbers are present. It should be understood that it does not exclude in advance the possibility of the presence or addition of steps, actions, components, parts or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Does not.

Tar vapor For reforming  Nickel catalyst and method for steam reforming of tar using same

The process of gasifying biomass, such as cellulose, is carried out at a high pressure, in which the generated gas contains a high content of tar. Accordingly, a catalytic steam reforming process is performed on the gasified product to decompose the tar, and a synthesis gas including hydrogen (H ₂ ) and carbon monoxide (CO) is produced.

At this time, the tar steam reforming process is performed in a high temperature tar decomposition equipment.

1 is a schematic configuration diagram illustrating a tar decomposition equipment in which a steam reforming process is performed according to an embodiment of the present invention.

Referring to FIG. 1, the tar decomposition equipment 10 in which the steam reforming process is performed is connected to a mixer 20 and a mixer 20 for providing and mixing benzene and water vapor, which are main components of tar, in the gasified product. And gas providing units 30 and 32 providing mixed gas and nitrogen of hydrogen and helium, a reactor 40 to which the mixed raw materials react, a heater 50 for heating the reactor 40, and , A temperature controller 52 for adjusting the temperature of the heater 50, a condenser 60 for quenching the mixed gas generated by being connected to the reactor 40, and a gas analyzer 70 for analyzing the condensed mixed gas. ), And gas lines 80, 82, 84 connecting the mixer 20, the reactor 40, the condenser 60, and the gas analyzer 70.

At this time, the tar produced in the process of gasifying the biomass comprises about 66% by weight of monocyclic aromatic hydrocarbons such as benzene and toluene, and about 22% by weight of polycyclic aromatic hydrocarbons such as naphthalene. In the present invention, a catalytic steam reforming process is performed using benzene (about 37.9 wt%), which is a major component of the tar.

Mixer 20 is maintained at a temperature of about 150 to 180 ℃, it is possible to preheat the benzene and steam mixture. The mixture of benzene and water vapor is sent to the reactor along the gas line 80, and reacts with water vapor in the reactor 40 at a temperature of 500 to 750 ℃ mixed with hydrogen (H ₂ ), carbon monoxide (CO) Gas and carbon dioxide (CO ₂ ), methane (CH ₄ ), water vapor (H ₂ O) and the like can be produced. At this time, the temperature of the reactor 40 is heated by the heater 50, it is possible to maintain the temperature range through the temperature controller 52. In the reaction for producing the mixed gas, a nickel catalyst having excellent activity is used.

Here, the connected gas lines 80 and 82 before and after the reactor 40 may be maintained at a temperature of 100 to 150 ° C to prevent condensation of water vapor. At this time, since the steam reforming reaction is very exothermic, the reactor 40 is composed of quartz to achieve good insulation.

The gas providing units 30 and 32 include a first gas providing unit 30 providing a mixed gas of hydrogen and helium, and a second gas providing unit 32 providing nitrogen. The mixed gas of hydrogen and helium is provided to maintain benzene-rich conditions before water vapor is provided. The nitrogen is used as a carrier gas to convey the mixture of benzene and water vapor through gas lines 80, 82, 84.

In the present invention, a catalyst in which nickel (Ni) is supported on a support including cerium oxide (CeO ₂ ) and zirconium oxide (ZrO ₂ ) is used as the catalyst used for the reforming reaction of benzene and steam. By catalyst is meant the entire catalyst structure comprising nickel and the support. For example, the catalyst may comprise about 55 to 70% by weight of cerium oxide and a support mixed with about 15 to 30% by weight zirconium oxide to increase the surface area for nickel impregnation, about 5 to 15% by weight of transition metal, Preferably it contains nickel (Ni).

Here, nickel (Ni), a metal synergistically with the cerium oxide and zirconium oxide, acts as an activation catalyst in the steam reforming reaction of benzene. In addition, the cerium oxide (CeO ₂ ) suppresses the deposition of hydrocarbons by oxidizing a hydrocarbon having a high boiling point. For this purpose, the support including the cerium oxide and zirconium oxide preferably contains 25 to 75% by weight of cerium oxide. According to one embodiment of the invention, the content of the solid hydrocarbon in the catalyst may be about 0.0001 to 0.3%. The zirconium oxide (ZrO ₂ ) increases the surface area of the catalyst and the distribution of nickel (Ni) as the content of zirconium (Zr) increases, thereby increasing the activity of the catalyst.

Further, the cerium oxide (CeO ₂₎ and nickel catalyst has a support comprising zirconium oxide (ZrO ₂₎ is cerium oxide (CeO ₂₎ and zirconium oxide (ZrO ₂₎ the surface area of the nickel catalyst wider than the sole use of the catalyst, respectively Excellent redox property. By the catalyst having the excellent redox property, the carbon components generated in the steam reforming reaction can easily react with the hydroxyl group generated while dissociating and adsorbing steam, thereby increasing the catalytic activity.

Accordingly, the nickel catalyst including the cerium oxide and zirconium oxide has a high activity of 80% or more, and effectively prevents the deposition of hydrocarbons to maintain the catalyst surface in an optimal state with good reactivity.

The hydrocarbons and water vapor of benzene in the mixture supplied on the catalyst surface in the reactor 40 react rapidly to produce a synthesis gas comprising hydrogen (H ₂ ) and carbon monoxide (CO), and trace amounts of carbon dioxide (CO ₂ ). In addition to the generation of water vapor (H ₂ O) and unreacted methane (CH ₄ ), heat is also generated by the exothermic reaction. Therefore, the high temperature synthesis gas (H ₂ , CO) is adjusted to a temperature suitable for the next process by cooling through the condenser 60 using water.

The component amount of the cooled synthesis gas may be analyzed by the gas analyzer 70 connected to the gas line. The gas analyzer 70 uses gas chromatography (GC), a gas chromatography-thermal conductivity detector (GC-TCD) for analyzing hydrogen, and a gas chromatography-flame (GC-FID) for analyzing gases including carbon elements. Ionization Detector). Here, hydrogen can be separated from the product gas and reused.

As mentioned, the tar steam reforming catalyst generated in the biomass gasification process of the present invention prevents the deposition of hydrocarbons, has a high reaction activity of the catalyst itself, and the degree to which the activity decreases with time is commercialized. It is less than Ni / Al ₂ O ₃ / SiO ₂ ) and can be used for a long time. Specifically, it can be seen that the nickel catalyst using a mixture of cerium oxide and zirconium oxide has a wide surface area, has excellent oxygen transport ability and oxygen storage ability, and thus has a high redox characteristic, so that the activity is more excellent. In addition, the nickel catalyst including the cerium oxide (CeO ₂ ) and zirconium oxide (ZrO ₂ ) can effectively prevent the deposition of hydrocarbons by oxidizing a high boiling point hydrocarbon to maintain the catalyst surface in an optimal state with good reactivity.

Hereinafter, a method for steam reforming of tar using a catalyst according to an embodiment of the present invention may be described as follows.

First, a reactor 40 including a support including cerium oxide and zirconium oxide and a catalyst containing nickel supported in the support is prepared. In this case, the support of the catalyst may contain 25 to 75% by weight of cerium oxide, the nickel may be included in the range of 5 to 15% by weight. The catalyst serves to easily react the carbon components generated in the steam reforming reaction of tar with a hydroxyl group generated by dissorption and adsorption of steam.

Subsequently, water vapor is mixed with the tar generated during the biomass gasification process to form a mixture. As an example, benzene, which is a main component of the tar, may be used. The benzene and water are injected into the mixer 20 of the tar cracking equipment 10. At this time, the mixer 20 is preheated to a temperature of 150 to 180 ℃ is mixed with the tar in the water vapor state.

The mixture is then fed to reactor 40 to decompose the tar in the presence of the catalyst. At this time, a carrier gas is used to supply the mixture to the reactor 40. Examples of the carrier gas may include hydrogen, helium, nitrogen, and the like. These gases may be used alone or in combination. The mixture and carrier gas are passed through a gas line 80 to a reactor 40 in which the catalyst is contained, all of the gas lines 80, 82, 84 having a temperature of 100 to 150 ° C. to prevent condensation of water vapor. Is maintained. The mixture is tar cracked under temperature conditions of 500 to 750 ° C. and in the presence of a catalyst. By the tar decomposition reaction, a reactant including a synthesis gas containing hydrogen and carbon monoxide can be obtained.

Here, since the reactants are generated at a high temperature by an exothermic reaction, a cooling process may be performed to cool the reactants before storing them. Cooling of the reactants is carried out through the condenser 60, the hydrogen gas may be stored separated from the reactant gas.

As described above, in the steam reforming process of tar using a nickel catalyst containing cerium oxide (CeO ₂ ) and zirconium oxide (ZrO ₂ ), even if the reaction time increases, the decrease in the activity of the catalyst is very small. Can be done. In addition, by using a catalyst having better activity than the conventional nickel catalyst, the decomposition efficiency of tar generated in the biomass gasification process can be increased.

The above-described tar reforming catalyst for tar and steam reforming tar using the same will be described in more detail with reference to the following examples, and the scope of the present invention is not limited to these examples.

Tar water vapor with good activity For reforming  Nickel catalyst manufacturers

The tar steam reforming catalyst generated in the biomass gasification process is prepared by using a coprecipitation method as in Examples 1 to 3 and Comparative Examples 1 to 5, and the support is a nickel precursor aqueous solution It was prepared by supporting it, then drying and baking.

Example  One

Tar metal vapor support for steam reforming was prepared by coprecipitation by reacting cerium oxide and zirconium oxide in a weight ratio of 75:25. Subsequently, a supporting process was performed in which the support was placed in an aqueous nickel nitrate solution (Ni (NO ₃ ) ₃ .6H ₂ O), which was a nickel precursor, and dissolved, and a precipitate was formed therein. The solution in which the precipitate is present was evaporated for 2 hours in a dryer at a temperature of about 120 ℃. At this time, the supporting process and drying process was repeated until the desired amount of nickel (Ni) is supported. Subsequently, the evaporated precipitate was completely dried in a dryer at a temperature of about 120 ° C. for about 24 hours and then calcined at about 500 ° C. in an air atmosphere for about 5 hours to prepare a catalyst for tar reforming of steam. At this time, the weight of the nickel was prepared to be about 15% by weight of the total catalyst weight.

Example  2

Example 2 prepared a catalyst for steam reforming of tar in substantially the same manner as in Example 1, but, unlike Example 1, the weight of nickel was made to be about 10% by weight of the total catalyst weight.

Example  3

Example 3 prepared a catalyst for steam reforming of tar in substantially the same manner as in Example 1, but unlike Example 1, the weight of nickel was made to be about 5% by weight of the total catalyst weight.

Comparative example  One

Comparative Example 1 prepared a catalyst for steam reforming of tar in substantially the same manner as in Example 1, but unlike Example 1, a support including aluminum oxide (Al ₂ O ₃ ) as a metal oxide support was prepared.

Comparative example  2

Comparative Example 2 prepared a catalyst for steam reforming of tar in substantially the same manner as in Example 1, but unlike Example 1, a support including cerium oxide (CeO ₂ ) as a metal oxide support was prepared.

Comparative example  3

Comparative Example 3 prepared a catalyst for steam reforming of tar in substantially the same manner as in Example 1, but unlike Example 1, a support including zirconium oxide (ZrO ₂ ) as a metal oxide support was prepared.

Comparative example  4

Comparative Example 4 prepared a catalyst for steam reforming of tar in substantially the same manner as in Example 1, but unlike Example 1, a support including olivine was used as the metal oxide support. At this time, the composition of the olivine is SiO ₂ 36.1% by weight, MgO 35.1% by weight, Fe ₂ O ₃ 12.3% by weight, CaO 3.4% by weight and Al ₂ O ₃ 1.3% by weight. In addition, the catalyst was impregnated with nickel (excess solution impregnation method), not the incipient wetness method, and after drying for 24 hours in a dryer of about 110 ℃ temperature of about 550 ℃ in the air atmosphere It was calcined at the temperature for 5 hours.

Comparative example  5

Comparative Example 5 prepared a commercially available nickel catalyst (Ni / Al ₂ O ₃ -SiO ₂ ) (trade name: Katalco 46-6Q, manufacturer: Johnson & Mattheys) supporting nickel in a support including silicon oxide and aluminum oxide. . At this time, the weight of nickel of the commercially available nickel catalyst is 16% by weight of the total catalyst weight.

Tar vapor For reforming  Activity Evaluation of Nickel Catalyst

In order to avoid the pressure drop in the activity test of each of the nickel catalysts prepared by Examples 1 to 3 and Comparative Examples 1 to 5, the pelletizing and pulverizing process was performed to select a size in the range of 20 to 50 mesh. It was. Subsequently, the activity was evaluated by steam reforming benzene in the tar cracking equipment for tar steam reforming using the nickel catalyst. At this time, the benzene was provided in an amount of more than about 800 times the content of tar (5-75 g / Nm ³ ) generated in the general biomass gasification process.

Specifically, tar decomposition equipment was prepared, preheated and air cooled, and about 0.3 g of the tar catalyst for reforming the tar of the tars of Examples 1 to 3 and Comparative Examples 1 to 5 was supplied into the reactor. At this time, the nickel catalyst was reduced to a temperature of about 750 ℃ for 3 hours while providing a mixture gas of about 10% hydrogen and helium at 100ml / min. Benzene and water, which are the main components of the tar, were first mixed into a mixer to form a mixture, and injected into the reactor at a rate of 0.7 ml / min and 1.0 ml / min using an HPLC (High performance liquid chromatography) pump, respectively. . The inside of the reactor was maintained at a temperature of 550 to 700 ℃, the reaction was performed for about 1 hour. At this time, nitrogen was used as a carrier gas and injected at a rate of 40 ml / min.

The gas produced after the reaction was sampled using a Teflon gas bag at 10 minute intervals. The sampled gas was injected into the GC as a gas analyzer using a syringe. Specifically, hydrogen was analyzed by GC-TCD, and argon (Ar) was used as a carrier gas. Carbon monoxide, carbon dioxide, and methane were analyzed by GC-FID, and helium (He) was used as a carrier gas. The column used for all GCs was a 5ft × 1/8 ”carboxen 1000 (Supelco), held at a temperature of about 40 ° C. for about 1 minute, heated up to a temperature of 225 ° C. at a rate of 20 ° C./min, and finally After maintaining for 1 minute to benzene conversion and product gas was analyzed.

At this time, the conversion rate of benzene was calculated using the following formula (1).

[B]: Benzene molarity (mol%)

Evaluation of the catalytic activity according to the type of support used in the steam reforming process of benzene, which is the main component of the tar, is shown in Table 1. At this time, CeO ₂ and in the catalyst of Examples 1 to 3 of Table 1 The content ratio (wt%) of ZrO ₂ is 75:25.

Table 1 Activity of the catalyst for benzene steam reforming prepared in Examples 1 to 3 and Comparative Examples 1 to 5

Looking at the results of the evaluation of the activity of the catalyst for Examples 1 to 3 and Comparative Examples 1 to 5 described in Table 1, as the reaction temperature and the content of nickel increased the conversion of benzene increased, based on the conversion of benzene In this case, it was found that the catalytic activity was increased in the order of Ni / ZrO ₂ <Ni / CeO ₂ <Ni / Al ₂ O ₃ <Ni / CeO ₂ (75%) / ZrO ₂ (25%).

In addition, it was found that the nickel catalyst of 15 wt% nickel of the present invention had better catalytic activity under the same reaction temperature conditions as compared to 16 wt% of nickel supported catalyst Katalpo 46-6Q.

In addition, the cerium oxide (CeO ₂ ) and the zirconium oxide (ZrO ₂ ) of Example 1 are mixed despite the lower surface area compared to the nickel catalyst using the support including aluminum oxide (Al ₂ O ₃ ) of Comparative Example 1. It was found that the nickel catalyst using one support had higher activity. Temperature-reduction (TPR) experiments were performed to confirm this.

Figure 2 is a graph showing the hydrogen consumption in the temperature reduction method (TPR) experiment of the catalyst according to Example 1 and the hydrogen consumption in the temperature reduction method (TPR) experiment of the catalyst according to Comparative Examples 1 to 3 and Comparative Example 5. In FIG. 2, "I" is a case using the catalyst according to Example 1, "II" is a case using the catalyst according to Comparative Example 3, and "III" is a case using the catalyst according to Comparative Example 2. , "IV" is the case of using the catalyst according to Comparative Example 1, "V" is the hydrogen consumption in the temperature reduction method (TPR) experiment when using the catalyst according to Comparative Example 5.

Referring to FIG. 2, it was confirmed that catalysts including cerium oxide (CeO ₂ ), zirconium oxide (ZrO ₂ ), and a mixture of cerium oxide and zirconium oxide (CeO ₂ / ZrO ₂ ) generally have high reducibility. At this time, the nickel catalyst (Ni / CeO ₂ / ZrO ₂ ) of Example 1 (I) showed isotropy at two locations and had the widest peak area. In addition, it was confirmed that the nickel catalyst of Example 1 (I) has a relatively high reducibility compared to the nickel catalyst (Ni / Al ₂ O ₃ ) containing aluminum oxide of Comparative Example 1 (IV). It was confirmed that the present invention had high reducibility compared to the commercially available nickel catalyst of Example 5 (V) (Ni / Al ₂ O ₃ / SiO ₂ ). Therefore, the nickel catalyst having excellent redox properties of the present invention can be easily reacted with the hydroxyl group generated by dissorption and adsorption of steam components of the carbon components generated in the steam reforming reaction, and has been shown to have improved catalytic activity. .

3 shows the conversion of benzene calculated by reaction time in the steam reforming process of benzene using the catalyst according to Example 1 and the reaction time of the steam reforming process of benzene using the catalysts according to Comparative Examples 1 and 5 It is a graph showing the calculated conversion of benzene. In FIG. 3, "■" is the case where the catalyst according to Comparative Example 1 is used, "●" is the case when the catalyst according to Comparative Example 5 is used, and "▲" is the case where the catalyst according to Example 1 is used. This shows the conversion of benzene over the steam reforming process time. In addition, Table 2 shows the content of solid hydrocarbons (coke, hereinafter referred to as 'coke') generated by the use of a catalyst in the steam reforming process of benzene, which is a major component of the tar. At this time, the amount of coke in Table 2 is a value obtained by calculating the amount of coke relative to the total nickel catalyst as a percentage.

[Table 2] Coke amount generated during the steam reforming reaction of benzene with catalysts prepared in Example 1 and Comparative Examples 1 and 5

Referring to FIG. 3, when the nickel catalyst according to Example 1 is used, the conversion rate of the initial benzene in the steam reforming reaction of benzene is higher than 80% compared to the nickel catalysts according to Comparative Examples 1 and 5, and the reaction time is higher. The decrease in the conversion of benzene was found to occur much smaller. These results can be explained in relation to the amount of coke generated during the heat treatment of the catalysts prepared in Example 1 and Comparative Examples 1 and 5 described in Table 2, and the amount of coke acts as a factor that lowers the catalyst life. Able to know. That is, in the case of the nickel catalyst including the support according to Comparative Examples 1 and 5, solid hydrocarbons (coke) are generated at 17.4% and 8.3%, respectively, in the nickel catalyst to reduce the active reaction of the catalyst, and the conversion rate of benzene It can be seen that also greatly reduced. However, it was found that the nickel catalyst according to Example 1 of the present invention had almost no coke amount of 0.1%, so that the activity of the catalyst caused by coke was very low.

As described above, the nickel catalyst (Ni / CeO ₂ / ZrO ₂ ) of the present invention used in the steam reforming process of tar is used by using a support mixed with cerium oxide and zirconium oxide, thereby making it a commercially available nickel catalyst (Ni / Al _2). Compared to O ₃ / SiO ₂ ), the activity of tar decomposition is excellent, and the activity decreases little over time, and thus can be used for a long time without replacement. Therefore, the decomposition efficiency by the catalytic steam reforming reaction of tar generated in the biomass gasification process can be increased.

The tar catalyst for reforming tar of the present invention uses a support mixed with cerium oxide and zirconium oxide, thereby cracking tar compared to conventional commercially available nickel catalysts (Ni / Al ₂ O ₃ / SiO ₂ ). The activity of is excellent, and even if time passes, there is little activity decrease and can use for a long time without replacement. Therefore, the decomposition efficiency by the catalytic steam reforming reaction of tar generated in the biomass gasification process can be increased.

Although the above has been described with reference to the preferred embodiments of the present invention, those of ordinary skill in the art may vary the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that modifications and variations can be made.

1 is a schematic diagram illustrating a tar decomposition chamber in which a steam reforming process is performed according to an embodiment of the present invention.

Figure 2 is a graph showing the hydrogen consumption in the temperature reduction method (TPR) experiment of the catalyst according to Example 1 and the hydrogen consumption in the temperature reduction method (TPR) experiment of the catalyst according to Comparative Examples 1 to 3 and Comparative Example 5.

3 shows the conversion of benzene calculated by reaction time in the steam reforming process of benzene using the catalyst according to Example 1 and the reaction time of the steam reforming process of benzene using the catalysts according to Comparative Examples 1 and 5 It is a graph showing the calculated conversion of benzene.

Explanation of symbols on the main parts of the drawings

10: tar decomposition equipment 20: mixer

30: gas providing unit 40: reactor

50: heater 52: thermostat

60: condenser 70: gas analyzer

80: gas line

Claims (6)

It is used at a temperature of 700 to 750 ° C. in a tar steam reforming process generated during a biomass gasification process, and includes a support including cerium oxide and zirconium oxide and nickel supported on the support. In the catalyst, the nickel contains 15% by weight, and the mixed weight ratio of the cerium oxide and the zirconium oxide is 75%: 25% of the catalyst for steam reforming of tar. delete delete A support comprising cerium oxide and zirconium oxide and nickel supported in the support, wherein the nickel comprises 15 wt% of the total catalyst, and the mixed weight ratio of the cerium oxide and the zirconium oxide is 75%: 25% Providing a reactor comprising a catalyst; Mixing water vapor with tar generated during the biomass gasification process to generate a mixture; And Supplying the mixture to a reactor to decompose the tar at a temperature of 700 to 750 ° C. in the presence of the catalyst. delete delete

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