JP2006257351A - Gasification gas aftertreatment catalyst reactor, system using the catalyst reactor, and gasification gas aftertreatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use a catalytic reactor for gasification gas aftertreatment capable of removing unsaturated hydrocarbons in gasification gas with a simple structure and hardly reducing energy efficiency, and using the catalyst reactor A system and gasification gas aftertreatment method are provided.
[MEANS FOR SOLVING PROBLEMS] A catalytic reactor (20) for aftertreatment of gasification gas contains a component active for hydrogenation reaction of unsaturated hydrocarbons in gasification gas produced by a biomass or waste gasification furnace. The hydrogenation catalyst having (22) was charged.
[Selection] Figure 1

Description

  The present invention relates to a gasification gas aftertreatment catalyst reactor that performs aftertreatment of gasification gas generated from biomass or waste, a system using the catalyst reactor, and a gasification gas aftertreatment method.

  In recent years, attempts have been made to gasify biomass and waste by pyrolysis or partial oxidation and use them as power generation fuel for gas engines, gas turbines, and fuel cells. Fuel cell power generation systems using unused biomass and waste as fuel can be expected to have high power generation efficiency, and are becoming increasingly important from the standpoint of energy resources and environmental conservation. In particular, power generation systems using fuel cells have low emissions of toxic substances such as nitrogen oxides and can efficiently generate power from small to medium distributed power sources to large power generation systems. Is expected.

In addition to the above power generation, a method of chemically converting hydrogen, carbon monoxide, and carbon dioxide generated by gasification using a catalyst and using it as a liquid fuel such as methanol, dimethyl ether, LPG, GTL fuel, etc. has been studied. ing.
The gasification reaction of biomass, waste, etc. can be generally expressed as follows in the case of gasification using steam.

CnHm + nH ₂ O → (m / 2 + n) H ₂ + nCO
nCO + nH ₂ O → nH ₂ + nCO ₂
That is, in the case of gasification using water vapor, hydrogen and carbon monoxide are generated by the reaction between the biomass component (CnHm) and the water vapor. Further, due to the presence of water vapor, a part of carbon monoxide is converted into carbon dioxide by a shift reaction.

Moreover, in the gasification reaction by partial oxidation reaction, hydrogen and carbon monoxide are produced | generated by reaction of a biomass component (CnHm) and oxygen.
CnHm + n / 2 O ₂ → m / 2 H ₂ + nCO
However, the gasification reaction is complicated, and various components are included in the gasification gas depending on gasification conditions such as the gasification method, temperature, and pressure, and the component concentrations thereof are also various. For example, when biomass is gasified, in addition to hydrogen, carbon monoxide and carbon dioxide as main components, paraffinic hydrocarbons such as methane, ethane, and propane, and tar having a high molecular weight depending on the gasification method Minutes may be generated. Also included as trace components are acetylene (C ₂ H ₂ ), unsaturated hydrocarbons such as ethylene (C ₂ H ₄ ), which is an olefinic hydrocarbon, and benzene (C ₆ H ₆ ), which is an aromatic hydrocarbon. It is.

As described above, in the gasification of biomass and waste, the concentrations of the main component and trace components in the gasification gas vary depending on the gasification method and conditions, and optimal gasification according to the purpose of using the gasification gas. It is necessary to select a method. In addition, it is necessary to clean the gasification gas and remove specific components in accordance with the purpose of using the gasification gas.
For example, when gasified gas is used as fuel for a fuel cell, it is necessary to reform hydrocarbons such as methane present in the gasified gas using a reforming catalyst. In addition, in order to adjust the calorific value of the gasification gas, when the gasification gas is mixed with a fuel such as city gas or natural gas, it is necessary to treat the gasification gas with a reforming catalyst. is there.

  For steam reforming of hydrocarbons such as methane, a catalyst having nickel as a main component of an active metal is usually used. However, at this time, if unsaturated hydrocarbons are present in the gasification gas, carbon deposition proceeds on the steam reforming catalyst even if the amount of unsaturated hydrocarbons is very small. The gas flow path in the catalyst layer may be blocked, leading to an increase in pressure loss or blockage of the reformer. Further, since carbon deposition proceeds even inside the catalyst pellets formed in a pellet form, the catalyst pellets may be collapsed and pulverized, which may accelerate the pressure loss increase and blockage of the catalyst layer. In this way, when the pressure loss increase or blockage of the catalyst layer occurs, for example, when gasified gas is used in the fuel cell power generation system, the power generation efficiency of the fuel cell power generation system may be reduced in a short period of time. Absent.

  Further, when gasified gas is used in a fuel cell power generation system, the same problem may occur when gasified gas is supplied directly as fuel for the fuel cell without passing through the reformer. In other words, molten carbonate fuel cells (MCFCs) and solid oxide fuel cells (SOFCs) use nickel-based electrode catalysts as fuel electrodes, but they are unsaturated. When the hydrocarbon component is supplied to the fuel electrode chamber, carbon deposition or pulverization of the electrode itself occurs on the electrode catalyst, and there is a concern that the pressure loss increases or the gas flow path is blocked as described above.

  Also, when synthesizing liquid fuel such as methanol, dimethyl ether, LPG, GTL fuel, etc. from gasified gas, the hydrocarbon component in the gasified gas and the hydrocarbon component mixed in the gasified gas are once used in the reformer. It is necessary to reform and convert it into a gasification gas mainly composed of hydrogen and carbon monoxide. In this case as well, as described above, There is concern about the collapse of the catalyst pellets.

  For this reason, for example, when gasification is performed by the partial oxidation method, it is conceivable to reduce the concentration of the unsaturated hydrocarbon component by increasing the amount of oxygen or air blown. However, when the amount of oxygen or air blown is increased in this way, the concentration of combustible gases such as hydrogen, carbon monoxide, and methane also decreases at the same time, reducing the calories that can be used as fuel. There's a problem. This is not desirable in fuel cell power generation systems where energy efficiency is critical.

Therefore, as a method of using the pyrolysis gasification gas of waste as a fuel for a fuel cell, for example, a method of separating and using hydrogen from the gasification gas has been proposed (see Patent Document 1). By using this method, in principle, it is possible to extract only hydrogen that does not contain impurities such as unsaturated hydrocarbons and use it as a fuel.
For the purpose of removing the tar content in the gasification gas, the gasification gas is cooled and washed to remove the tar content, and a gasification gas containing the tar content is introduced into the high-temperature reformer. A method for decomposing and removing the tar content at a high temperature has been proposed (see Patent Documents 2, 3, and 4). If this method is used, it is considered possible to decompose and remove a trace amount of unsaturated hydrocarbon components in the process of removing the tar content in the gasification gas.
JP 2000-313892 A JP 2004-275901 A JP 2004-115688 A JP 2004-75852 A

However, the method disclosed in Patent Document 1 consumes a large amount of energy for hydrogen separation from the gasification gas, is expensive, and is not practical.
In the case of the methods disclosed in Patent Documents 2, 3, and 4, the gasification gas must be introduced into the high-temperature reformer, and the removal of a minute amount of unsaturated hydrocarbons reduces the energy efficiency. It is difficult to say that it is practical.

Thus, for example, even when gasified gas is used as fuel for fuel cells, various fuel cell power generation systems have been developed so far, and at present, practical systems are provided in terms of energy efficiency and cost. It has not been done.
The present invention has been made to solve such problems, and the object of the present invention is to provide unsaturated carbonization in a gasification gas at a low cost with almost no reduction in energy efficiency with a simple configuration. It is an object of the present invention to provide a gasification gas aftertreatment catalyst reactor capable of removing hydrogen, a system using the catalyst reactor, and a gasification gas aftertreatment method.

  In order to achieve the above-mentioned purpose, as a result of intensive investigations on measures for selectively removing unsaturated hydrocarbons, a removal method using a catalyst is most suitable in terms of energy efficiency and cost, especially By using a hydrogenation catalyst that has an active component in the hydrogenation reaction (hydrogenation) of unsaturated hydrocarbons, it is possible to efficiently remove unsaturated hydrocarbons using hydrogen originally contained in the gasification gas. I found out.

Based on such knowledge, the catalytic reactor for gasification gas aftertreatment according to claim 1 includes a hydrogenation catalyst having a component active for hydrogenation reaction of unsaturated hydrocarbons in the gasification gas. It is characterized by that.
As a result, the hydrogenation reaction of the unsaturated hydrocarbon is promoted by the hydrogenation catalyst using the hydrogen originally contained in the gasification gas, and the unsaturated hydrocarbon in the gasification gas is favorably removed.

That is, typical unsaturated hydrocarbon components are acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ), but acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ) are hydrogenated as follows. The reaction successfully converts to ethane.
C ₂ H ₂ + 2H ₂ → C ₂ H ₆
C ₂ H ₄ + H ₂ → C ₂ H ₆
At this time, since the catalytic reactor exhibits a good catalytic action from a low temperature, the energy required for reheating the gasification gas and heating the reactor can be minimized.

Further, since the unsaturated hydrocarbon component is removed satisfactorily both at normal pressure and under pressure, energy for boosting the gasification gas is unnecessary.
Further, since the unsaturated hydrocarbon component is satisfactorily removed regardless of the superficial velocity, the reactor main body can be small and space can be saved.
When acetylene and ethylene are converted to ethane in this way, since ethane is a saturated hydrocarbon, even if gasified gas is fed to, for example, a reforming catalyst mainly composed of nickel or an electrode of a fuel cell. Under normal operating conditions, carbon deposition and catalyst / electrode collapse hardly progress on the reforming catalyst or fuel cell electrode.

The catalytic reactor for aftertreatment of gasification gas according to claim 2, wherein the hydrogenation catalyst is characterized in that at least one of palladium, platinum, ruthenium, rhodium, copper, manganese, chromium and vanadium is activated. And is supported on any one of alumina, silica, titania and zirconia.
As a result, even if no special component (active metal, etc.) is required, the catalyst can suppress the progress of methanation of carbon monoxide and carbon dioxide (methanation), which is a side reaction other than unsaturated hydrocarbons. The reactor is easily configured.

According to a third aspect of the present invention, there is provided the catalytic reactor for aftertreatment of gasification gas according to the first or second aspect, further comprising temperature adjusting means for adjusting the temperature of the hydrogenation catalyst to a predetermined temperature range.
Accordingly, the hydrogenation reaction is efficiently promoted by adjusting the temperature of the hydrogenation catalyst to a predetermined temperature range.

For example, when the temperature of the hydrogenation catalyst exceeds about 400 ° C., the methanation reaction (methanation) tends to proceed as a side reaction, so that the temperature of the hydrogenation catalyst is within a predetermined temperature range of less than about 400 ° C. as much as possible. By adjusting to (for example, 80 to 300 ° C.), the progress of the side reaction is suppressed.
The gasification system according to claim 4 is provided in a gasification furnace that generates gasification gas from biomass or waste, and a gasification gas flow path generated in the gasification furnace. And a catalytic reactor for gasification gas aftertreatment as described above.

As a result, unsaturated hydrocarbons in the gasification gas using biomass and waste are well removed, and an efficient gasification system is realized.
In the fuel cell power generation system according to claim 5, the gasification gas aftertreatment catalyst reactor according to any one of claims 1 to 3 provided in a gasification gas flow path, and the gasification gas flow path in the gasification gas flow path. A reforming catalyst device provided downstream of the catalytic reactor for gasification gas aftertreatment and reforming the gasification gas; and the reforming after-treatment by the catalytic reactor for gasification gas aftertreatment and the reforming And a fuel cell that generates power using the gasified gas reformed by the catalyst device.

As a result, the progress of carbon deposition on the reforming catalyst and the fuel cell electrode and the collapse of the catalyst and the electrode are prevented, and an efficient fuel cell power generation system is realized.
6. The chemical conversion system according to claim 6, wherein the gasification gas aftertreatment catalyst reactor according to any one of claims 1 to 3 provided in a gasification gas flow path, and the gasification gas flow path in the gasification gas flow path. A reforming catalyst device provided downstream of the catalytic reactor for gasification gas post-treatment and reforming the gasification gas; and the reforming catalyst after-treatment by the catalytic reactor for gasification gas post-treatment And a chemical converter for converting the gasified gas reformed by the apparatus into a liquid fuel.

As a result, the progress of carbon deposition and catalyst collapse in the reforming catalyst is prevented, and an efficient chemical conversion system is realized.
8. The gasification gas aftertreatment method according to claim 7, wherein the unsaturated hydrocarbon in the gasification gas generated from biomass or waste has a component active for hydrogenation reaction of the unsaturated hydrocarbon. It removes by.

  As a result, gasification using biomass and waste tends to contain a relatively large amount of unsaturated hydrocarbons, but the gasification gas contains components that are active against the hydrogenation reaction of unsaturated hydrocarbons. Unsaturated hydrocarbons in the gasification gas are satisfactorily removed by passing through the hydrogenation catalyst having, even if the gasification gas is fed to, for example, a reforming catalyst mainly composed of nickel or an electrode of a fuel cell, The progress of carbon deposition on the reforming catalyst and the fuel cell electrode and the collapse of the catalyst and the electrode are prevented.

The gasification gas aftertreatment method according to claim 8, wherein the hydrogenation catalyst is at least one of palladium, platinum, ruthenium, rhodium, copper, manganese, chromium and vanadium as the active component. And supported on any one of alumina, silica, titania, ceria and zirconia.
As a result, the unsaturated hydrocarbon in the gasification gas can be suppressed while suppressing the progress of the methanation reaction (methanation), which is a side reaction, without requiring a special component (active metal, etc.) for the hydrogenation catalyst. Removed well.

The gasification gas aftertreatment method according to a ninth aspect is characterized in that, in the seventh or eighth aspect, the temperature of the hydrogenation catalyst is adjusted to a predetermined temperature range.
Thus, by adjusting the temperature of the hydrogenation catalyst to a predetermined temperature range, the hydrogenation reaction is efficiently promoted, and in particular, the progress of the methanation reaction (methanation), which is a side reaction, is suppressed.

  According to the catalytic reactor for aftertreatment of gasified gas according to claim 1, the additional energy input such as heating and pressurization is minimized, no additional hydrogen is required, and the reactor main body is downsized. Unsaturated hydrocarbons in the gasification gas can be removed with a simple structure with high efficiency and at low cost, and even if the gasification gas is fed to, for example, a reforming catalyst mainly composed of nickel or an electrode of a fuel cell Further, it is possible to prevent carbon deposition on the reforming catalyst and the fuel cell electrode and collapse of the catalyst and the electrode, and efficiently prevent the performance degradation of the reforming catalyst and the fuel cell.

According to the catalytic reactor for aftertreatment of gasified gas according to claim 2, the catalytic reaction is carried out while suppressing the progress of the methanation reaction (methanation) which is a side reaction without requiring a special component (active metal or the like). The device can be configured easily.
According to the catalytic reactor for gasification gas aftertreatment according to claim 3, the hydrogenation reaction can be efficiently promoted by adjusting the temperature of the hydrogenation catalyst to a predetermined temperature range, and in particular, a methanation reaction which is a side reaction. The progress of (methanation) can be suppressed.

According to the gasification system of claim 4, it is possible to remove unsaturated hydrocarbons in the gasification gas with a simple configuration while efficiently utilizing biomass and waste, and to remove the hydrocarbons efficiently and at low cost. System can be realized.
According to the fuel cell power generation system of claim 5, the unsaturated hydrocarbon in the gasification gas is removed with high efficiency and at a low cost with a simple structure, carbon deposition on the reforming catalyst and the fuel cell electrode, By preventing the electrode from collapsing, it is possible to efficiently prevent the performance degradation of the reforming catalyst and the fuel cell, and a fuel cell power generation system with high power generation efficiency can be realized.

According to the chemical conversion system of claim 6, unsaturated hydrocarbons in the gasification gas are removed with high efficiency and at a low cost with a simple structure, and carbon deposition and catalyst collapse in the reforming catalyst are efficiently prevented. And a chemical conversion system with high conversion efficiency can be realized.
According to the aftertreatment method of the gasified gas according to the seventh aspect, unsaturated hydrocarbons in the gasified gas can be removed with high efficiency and at a low cost with a simple configuration while effectively utilizing biomass and waste.

According to the aftertreatment method of the gasification gas according to claim 8, the progress of the methanation reaction (methanation), which is a side reaction, is suppressed even if a special component (active metal, etc.) is not required for the hydrogenation catalyst. Meanwhile, unsaturated hydrocarbons in the gasification gas can be removed with high efficiency and low cost.
According to the aftertreatment method of the gasified gas according to claim 9, the hydrogenation reaction can be efficiently promoted by adjusting the temperature of the hydrogenation catalyst to a predetermined temperature range, and in particular, a methanation reaction (metathesis) which is a side reaction. Nation) can be suppressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a gasification gas aftertreatment catalyst reactor, a system using the catalyst reactor, and a gasification gas aftertreatment method according to the present invention will be described below with reference to the accompanying drawings.
FIG. 1 schematically shows a fuel cell power generation system including a gasification system equipped with the catalytic reactor as an example of a system using the catalytic reactor for gasification gas aftertreatment according to the present invention. The configuration of the fuel cell power generation system will be described below.

The fuel cell power generation system mainly includes a gasifier 10, a reformer 30, and a fuel cell 40.
The gasification furnace 10 is an apparatus that generates gasified gas by gasifying a solid fuel such as biomass or waste by thermal decomposition. Various gasification furnaces 10 are known, and a detailed description thereof will be omitted here.

The gasification gas generated in the gasification furnace 10 contains hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), methane (CH ₄ ) and the like as main components, and the gasification The gas is fed to the reformer 30.
The reformer 30 has a reforming catalyst 32 therein and supplies steam (H ₂ O) to convert methane (CH ₄ ) generated in the gasification furnace 10 into hydrogen (CH ₂ ) by the following reforming reaction. H ₂ ) and catalytic device for conversion to carbon monoxide (CO).

CH ₄ + H ₂ O → 3H ₂ + CO
Thereby, methane in gasification gas is satisfactorily converted into hydrogen and carbon monoxide having high utility value.
Here, as the reforming catalyst 32, a pellet catalyst having nickel (Ni) as a main component of an active metal is generally adopted, but a catalyst having a structure in which a catalyst is supported on a honeycomb structure carrier may be used.

The gasified gas that has passed through the reformer 30 is supplied to the electrode catalyst in the fuel electrode chamber of the fuel cell 40, and hydrogen (H ₂ ) and carbon monoxide (CO) in the gasified gas are supplied to the fuel cell. It is used as fuel to generate electricity.
As the fuel cell 40, a molten carbonate fuel cell (MCFC) or a solid oxide fuel cell (SOFC) using a nickel (Ni) electrode catalyst as a fuel electrode is generally used. Note that these fuel cells are publicly known, and details thereof are omitted here.

Incidentally, the gasification gas produced from a solid fuel such as biomass and waste in the gasification furnace 10 also includes a acetylene (C ₂ H ₂₎ and ethylene (C ₂ H ₄₎ as a minor component. However, as described above, these unsaturated hydrocarbons such as acetylene and ethylene cause carbon deposition on or inside the catalyst containing nickel (Ni) as a main component of the active metal, and the deposited carbon is deposited in the catalyst layer. There is a possibility that the gas flow path of the reformer 30 may be clogged, or the catalyst pellets may be disintegrated and pulverized to increase the pressure loss or the clogging of the reformer 30. Similarly, carbon deposition may occur on the nickel (Ni) -based electrode catalyst of the fuel cell 40 or inside the electrode, and the deposited carbon or electrode may be pulverized, leading to an increase in pressure loss or a gas channel blockage.

For this reason, in the gasification gas flow path, these unsaturated hydrocarbons such as acetylene and ethylene should be removed, that is, unsaturated hydrocarbons should be converted to saturated hydrocarbons by hydrogenation reaction (hydrogenation). The hydrogenation reactor (catalyst reactor for aftertreatment of gasification gas) 20 according to the present invention is interposed between the gasification furnace 10 and the reformer 30.
The hydrogenation reactor 20 is configured such that the inside thereof is filled with a hydrogenation catalyst 22, that is, a catalyst having an active metal active in the hydrogenation reaction of an unsaturated hydrocarbon. As the hydrogenation catalyst 22, the target hydrogenation reaction of unsaturated hydrocarbons can be selectively performed, while side reactions other than the hydrogenation reaction, such as carbon monoxide (CO) and A catalyst that does not cause methanation of carbon (CO ₂ ) is applied.

CO + 3H ₂ → CH ₄ + H ₂ O
CO ₂ + 4H ₂ → CH ₄ + 2H ₂ O
The use of a catalyst that does not cause a side reaction in this way is an exothermic reaction, and when it occurs, the temperature of the whole or a part of the catalyst layer is remarkably increased and thermal decomposition of hydrocarbon components occurs. This is because, for example, carbon deposition that should be suppressed may be induced instead.

As such a catalyst, a catalyst having palladium (Pd), platinum (Pt) or the like as an active metal and supported on a carrier such as alumina, titania, ceria, zirconia or the like is preferable.
However, the hydrogenation catalyst 22 is not limited to these, and the hydrogenation catalyst 22 may be palladium (Pd), platinum (Pt), ruthenium (Ru), rhodium (Rh), copper (Cu), manganese (Mn), chromium (Cr ) And vanadium (V) as an active metal, and may be supported on any one of alumina, silica, titania, ceria and zirconia.

In addition, although the pellet catalyst is generally employed for the hydrogenation catalyst 22, it may be in the form of a tablet or a structure in which the catalyst is supported on a honeycomb structure carrier.
The hydrogenation reactor 20 is provided with a temperature adjusting device (temperature adjusting means, an electric heater with a thermostat, etc.) for adjusting the temperature of the hydrogenation catalyst 22. Thereby, the temperature of the hydrogenation catalyst 22 is adjusted to a predetermined temperature range, and the hydrogenation catalyst 22 is maintained in a state in which the hydrogenation reaction can proceed smoothly. Here, the predetermined temperature range may be a temperature range in which carbon deposition due to thermal decomposition of the hydrocarbon component can be suppressed. For example, the predetermined temperature range may be room temperature to 600 ° C. Considering that the methanation reaction (methanation), which is a reaction, takes place at about 400 ° C. or higher, it is preferably in the range of 80 ° C. to 300 ° C.

If the hydrogenation reactor 20 is brought closer to the gasification furnace 20, the temperature of the hydrogenation catalyst 22 can be raised satisfactorily, which is effective.
As a result, unsaturated hydrocarbons such as acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ) are converted into ethane (C ₂ H ₆ ), that is, saturated hydrocarbons in the hydrogenation reactor 20 by the following hydrogenation reaction. Converts well.

C ₂ H ₂ + 2H ₂ → C ₂ H ₆
C ₂ H ₄ + H ₂ → C ₂ H ₆
In the hydrogenation reaction, hydrogen contained in the gasification gas is used as it is, but additional hydrogen can be injected from the upstream portion of the hydrogenation reactor 20 as necessary. It is.

When ethane (C ₂ H ₆ ) is generated by the hydrogenation reaction in this way, the ethane is converted into hydrogen (H) by the following reforming reaction in the reformer 30 in the same manner as the methane (CH ₄ ). ₂ ) and carbon monoxide (CO), and is effectively used as fuel for the fuel cell 40.
C ₂ H ₆ + 2H ₂ O → 5H ₂ + 2CO
Hereinafter, based on Examples 1 to 5 and Comparative Examples 1 and 2, the action and effect of the gasification gas aftertreatment catalyst reactor according to the present invention, the system using the catalyst reactor, and the gasification gas aftertreatment method explain.

[Example 1]
An alumina catalyst supporting palladium (Pd) is used as a hydrogenation catalyst, and hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), methane (CH ₄ ) and nitrogen ( Catalyst layer temperature when gasified gas containing 3350 ppm and 4620 ppm of acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ), which are unsaturated hydrocarbons, flows in a gas mainly containing N ₂ ) The relationship between (average temperature) and the gas composition (concentration) at the catalyst layer outlet is shown in FIGS. At this time, the pressure of the reactor filled with the hydrogenation catalyst is 200 kPa (G), and the superficial velocity is 2900 / hr. Gas composition analysis includes a gas chromatograph analyzer using a FID (Flame Ionization Detector) capable of analyzing traces of unsaturated hydrocarbons, and hydrogen, carbon monoxide, carbon dioxide, which are the main components of the gasification gas, The analysis was carried out using a gas chromatograph analyzer using a TCD (Thermal Conductivity Detector) capable of analyzing methane and nitrogen with high sensitivity.

From the relationship between the acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ) and ethane (C ₂ H ₆ ) concentrations shown in FIG. 2 and the catalyst layer temperature, hydrogenation of acetylene and ethylene to ethane was carried out on this catalyst. It can be seen that the reaction proceeds efficiently. The progress of the hydrogenation reaction proceeds in the order of the hydrogenation reaction of acetylene to ethylene and the hydrogenation reaction of ethylene to ethane as the temperature of the catalyst layer increases from low to high.

From the relationship between the hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ) and methane (CH ₄ ) concentrations shown in FIG. 3 and the catalyst layer temperature, the concentration of these gas components is determined by the inlet gas composition ( It can be seen that it is almost the same as “in”. That is, although the hydrogenation reaction of acetylene and ethylene proceeds on this catalyst, side reactions such as methanation reactions do not proceed over a wide temperature range.

[Example 2]
As the hydrogenation catalyst, the same alumina catalyst as in Example 1 was used, and the alumina catalyst contained 335 ppm and 462 ppm of acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ), respectively, in the gas composed of the main components. FIG. 4 shows the relationship between the catalyst layer temperature (average temperature) and the gas composition (concentration) at the catalyst layer outlet when the gasification gas is flowed. At this time, the pressure of the reactor filled with the hydrogenation catalyst is 200 kPa (G), and the superficial velocity is 2900 / hr.

From the relationship between the acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ) and ethane (C ₂ H ₆ ) concentrations shown in FIG. 4 and the catalyst layer temperature, acetylene and ethylene are low in concentration on this catalyst. It can also be seen that the hydrogenation reaction of acetylene and ethylene to ethane proceeds efficiently. In addition, side reactions such as methanation reaction do not proceed over a wide temperature range in the relationship between hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), methane (CH ₄ ) concentration and catalyst layer temperature. Is the same as in the first embodiment.

[Example 3]
The same alumina catalyst as in Examples 1 and 2 was used as a hydrogenation catalyst, and acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ) in the gas composed of the above main components were 3350 ppm and 4620 ppm, respectively. FIG. 5 shows the relationship between the pressure in the reactor filled with the hydrogenation catalyst and the gas composition (concentration) at the catalyst layer outlet when the gasification gas contained is flowed. At this time, the temperature of the hydrogenation catalyst is 200 ° C.
From the relationship between the acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), ethane (C ₂ H ₆ ) concentration and reactor pressure shown in FIG. 5, the hydrogenation reaction of acetylene and ethylene to ethane It can be seen that the process proceeds efficiently regardless of the pressure.

[Example 4]
The same alumina catalyst as in Examples 1, 2 and 3 was used as the hydrogenation catalyst, and the gas composition at the catalyst layer outlet when the gasified gas containing water vapor was passed through the alumina catalyst and the catalyst layer outlet. The relationship with (concentration) is shown in FIGS. The concentration of water vapor was 25%, which is sufficiently high as the water vapor concentration contained in the gasification gas. At this time, the concentrations of acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ) contained in the gasification gas were 335 ppm and 462 ppm, respectively, and the pressure of the reactor filled with the hydrogenation catalyst was 0 kPa (G) ( Normal pressure), the superficial velocity was 1935 / hr.

From the relationship between the acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ) and ethane (C ₂ H ₆ ) concentrations shown in FIG. 6 and the catalyst layer temperature, a gasified gas containing a large amount of water vapor on the catalyst. Even when the superficial velocity is low, the hydrogenation reaction of acetylene and ethylene to ethane can proceed efficiently.
From the relationship between the hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ) and methane (CH ₄ ) concentrations shown in FIG. 7 and the catalyst layer temperature, the concentrations of these gas components are at any temperature. Shows the same value as the concentration at the inlet of the catalyst layer, and it can be seen that side reactions such as methanation do not proceed even in the presence of water vapor or when the superficial velocity is low.

[Example 5]
As a hydrogenation catalyst, an alumina catalyst in which both palladium (Pd) and platinum (Pt) are supported on an alumina carrier is used, and hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ) is used as the alumina catalyst. ), Gasified gas containing 335 ppm and 462 ppm of acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ), which are unsaturated hydrocarbons, in a gas mainly composed of methane (CH ₄ ) 8 and 9 show the relationship between the catalyst layer temperature (average temperature) and the gas composition (concentration) at the catalyst layer outlet. At this time, the pressure of the reactor filled with the hydrogenation catalyst is 0 kPa (G) (normal pressure), and the superficial velocity is 2900 / hr.

From the relationship between the acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), ethane (C ₂ H ₆ ) concentration and catalyst layer temperature shown in FIG. It can be seen that the hydrogenation reaction of ethylene to ethane proceeds efficiently.
From the relationship between the hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), methane (CH ₄ ) concentration and catalyst layer temperature shown in FIG. It can be seen that side reactions such as reactions do not proceed.

[Comparative Example 1]
As Comparative Example 1, unsaturated carbonization is performed in a gas mainly containing hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), and methane (CH ₄ ) without being charged with a hydrogenation catalyst. Reactor temperature (average temperature) and gas at the outlet of the reactor when gasified gas containing 3350 ppm and 4620 ppm of acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ), which are hydrogen, is flowed to the reactor, respectively. The relationship with the composition (concentration) is shown in FIG. At this time, water vapor does not exist in the gasification gas (dry), and the pressure of the reactor is 0 kPa (G) (normal pressure).

As shown in FIG. 10, as the reactor temperature increases, the acetylene concentration gradually decreases while the ethylene concentration increases. This shows that the hydrogenation reaction from acetylene to ethylene partially proceeds. However, in order to convert most of the acetylene to ethylene, a temperature of 200 ° C. or higher is required, and the reaction efficiency is lower than when a hydrogenation catalyst is used, and a higher reaction temperature is required. Recognize. Also, generation of ethane (C ₂ H ₆ ) is not observed over the entire temperature range, and when no catalyst is present, the hydrogenation reaction is completed up to ethylene, from the viewpoint of removing unsaturated hydrocarbons. It can be said that it is insufficient.

[Comparative Example 2]
As Comparative Example 2, as in Comparative Example 1, hydrogen (H ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), and methane (CH ₄ ) were used as the main components without charging the hydrogenation catalyst. Temperature (average temperature) when gasified gas containing 3350 ppm and 4620 ppm of acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ), which are unsaturated hydrocarbons, in the gas to be fed to the reactor 11 shows the relationship between the gas composition and the gas composition (concentration) at the reactor outlet. However, in Comparative Example 2, the gasified gas contains 25% of water vapor (wet).

As shown in FIG. 11, even when a gasification gas containing water vapor is flowed, as in Comparative Example 1, the hydrogenation reaction proceeds only to ethylene, and its efficiency is also improved when a hydrogenation catalyst is used. It can be seen that it is extremely low. Similarly to Comparative Example 1, ethane (C ₂ H ₆ ) is not generated over the entire temperature range, ethylene remains, and it is still insufficient from the viewpoint of removing unsaturated hydrocarbons in the gasification gas. It is a thing.

As described above, according to the catalytic reactor for gasification gas aftertreatment according to the present invention, the system using the catalyst reactor, and the gasification gas aftertreatment method, the hydrogenation catalyst 22 of the hydrogenation reactor 20 is used. Hydrogenation reaction of unsaturated hydrocarbons such as acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ) using hydrogen originally contained in the gasification gas and no methanation reaction (methanation) The unsaturated hydrocarbons such as acetylene and ethylene in the gasified gas can be favorably removed regardless of the concentration and regardless of the presence or absence of water vapor. That is, unsaturated hydrocarbons such as acetylene (C ₂ H ₂ ) and ethylene (C ₂ H ₄ ) can be favorably converted to ethane (C ₂ H ₆ ), which is a saturated hydrocarbon.

At this time, since the hydrogenation catalyst 22 exhibits a good catalytic action from a low temperature, the hydrogenation catalyst 22 is adjusted to a predetermined temperature range by the temperature adjusting means and the catalyst performance is suitably maintained. Energy required for gas reheating and reactor heating can be minimized.
Further, the unsaturated hydrocarbon component can be removed satisfactorily both at normal pressure and under pressure, and energy required for pressurization of the gasification gas can be completely eliminated.

Furthermore, since unsaturated hydrocarbon components can be removed satisfactorily regardless of the superficial velocity, the hydrogenation reactor 20 can be reduced in size, space can be saved, and can be loaded into the gasification furnace 20. It is.
As a result, it is possible to remove unsaturated hydrocarbons such as acetylene and ethylene in the gasification gas with a simple structure and efficiently and at low cost while effectively utilizing biomass and waste. System can be realized.

  When the unsaturated hydrocarbon such as acetylene or ethylene is converted into ethane, which is a saturated hydrocarbon, the gasification gas is a catalyst or fuel cell of the reformer 30 whose main component is nickel (Ni). Even if it is fed to the electrode catalyst of 40, it is possible to suppress the progress of carbon deposition or catalyst and electrode collapse in the catalyst of the reformer 30 and the electrode catalyst of the fuel cell 40 under normal operating conditions. The performance degradation of the reformer 30 and the fuel cell 40 can be efficiently prevented, and a fuel cell power generation system with high power generation efficiency can be constructed.

  Although not shown, even when the hydrogenation reactor 20 is used in a chemical conversion system that converts gasified gas into liquid fuel, carbon deposition or catalyst may occur in the catalyst of the reformer 30 under normal operating conditions. It is possible to prevent the degradation of the gas from progressing, to effectively prevent the performance of the reformer 30 from being deteriorated, and to construct a chemical conversion system with high conversion efficiency.

It is the schematic which shows a fuel cell power generation system as an example of the system using the catalytic reactor for gasification gas aftertreatment concerning the present invention. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Example 1, and the gas composition (concentration) at the catalyst layer exit. FIG. 6 is another diagram showing the relationship between the catalyst layer temperature (average temperature) and the gas composition (concentration) at the catalyst layer outlet in Example 1. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Example 2, and the gas composition (concentration) at the catalyst layer exit. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Example 3, and the gas composition (concentration) at the catalyst layer exit. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Example 4, and the gas composition (concentration) at the catalyst layer exit. FIG. 10 is another diagram showing the relationship between the catalyst layer temperature (average temperature) and the gas composition (concentration) at the catalyst layer outlet in Example 4. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Example 5, and the gas composition (concentration) at the catalyst layer exit. FIG. 10 is another diagram showing the relationship between the catalyst layer temperature (average temperature) and the gas composition (concentration) at the catalyst layer outlet in Example 5. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Comparative Example 1, and the gas composition (concentration) at the catalyst layer outlet. It is a figure which shows the relationship between the catalyst layer temperature (average temperature) in Comparative Example 2, and the gas composition (concentration) at the catalyst layer outlet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gasification furnace 20 Hydrogenation reactor 22 Hydrogenation catalyst 30 Reformer 32 Reforming catalyst 40 Fuel cell

Claims (9)

  A catalytic reactor for aftertreatment of gasification gas, comprising a hydrogenation catalyst having a component active for hydrogenation of unsaturated hydrocarbons in gasification gas.   The hydrogenation catalyst has at least one of palladium, platinum, ruthenium, rhodium, copper, manganese, chromium and vanadium as the active component, and is a support of any one of alumina, silica, titania, ceria and zirconia The catalytic reactor for gasification gas aftertreatment according to claim 1, wherein the catalytic reactor is supported on the gasification gas.   The catalytic reactor for gasification gas aftertreatment according to claim 1 or 2, further comprising temperature adjusting means for adjusting the temperature of the hydrogenation catalyst to a predetermined temperature range. A gasification furnace that generates gasification gas from biomass and waste;
The catalytic reactor for gasification gas post-treatment according to any one of claims 1 to 3, provided in a flow path of gasification gas generated in the gasification furnace,
A gasification system comprising: A catalytic reactor for gasification gas aftertreatment according to any one of claims 1 to 3, provided in a gasification gas flow path,
A reforming catalyst device provided in the gasification gas flow path downstream of the gasification gas aftertreatment catalyst reactor, and reforming the gasification gas;
A fuel cell that generates power using the gasification gas that has been post-treated by the gasification gas post-treatment catalytic reactor and reformed by the reforming catalyst device;
A fuel cell power generation system comprising: A catalytic reactor for gasification gas aftertreatment according to any one of claims 1 to 3, provided in a gasification gas flow path,
A reforming catalyst device provided in the gasification gas flow path downstream of the gasification gas aftertreatment catalyst reactor, and reforming the gasification gas;
A chemical converter for converting the gasification gas after-treated by the gasification gas after-treatment catalyst reactor and reformed by the reforming catalyst device into liquid fuel;
A chemical conversion system characterized by comprising:   After gasification gas characterized in that unsaturated hydrocarbons in gasification gas produced from biomass and waste are removed by a hydrogenation catalyst having a component active for the hydrogenation reaction of the unsaturated hydrocarbon Processing method.   The hydrogenation catalyst has at least one of palladium, platinum, ruthenium, rhodium, copper, manganese, chromium and vanadium as the active component, and is a support of any one of alumina, silica, titania, ceria and zirconia The gasification gas post-treatment method according to claim 7, wherein the gasification gas after-treatment method is supported on the gas.   The gasification gas aftertreatment method according to claim 7 or 8, wherein the temperature of the hydrogenation catalyst is adjusted to a predetermined temperature range.

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