JP2003055671A - Treating method of crude coke-oven gas and treatment system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new recovery technique and energy saving system of heat energy, and a new energy creative system that in view of the present state that sensible heat is not effectively used due to a quenching treatment by spraying ammonia water, in spite of a coke-oven gas comprising a coal volatile matter as a principal component, generated by dry distilling coal to produce coke, and retaining high temperature sensible heat near at 800 deg.C at a nascent time, comprises introducing a catalytic cracking reaction into a heavy hydrocarbon accompanied with the high temperature gas to convert the heavy hydrocarbon into light-duty chemical energy as an effectively utilizing technique of the sensible heat. SOLUTION: The converting method of the heat energy and heavy chemical energy into highly efficient clean light-duty chemical energy and its system comprise passing the crude COG accompanied with the heavy hydrocarbon through a heavy hydrocarbon cracking catalytic reactor, thereby effectively utilizing the sensible heat and converting the heavy hydrocarbon into light-duty hydrocarbon, demanding ion circumstances, continuously pas the resultant product through an oxide ion and electron mixing conductive solid electrolyte membrane type reactor, and practically using oxygen permselective performance of the solid electrolyte membrane to convert into a synthesis gas due to partial oxidation modification.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a coke oven gas whose main component is a coal volatile matter produced in a coke oven for carbonizing carbon to produce coke, and has a high temperature sensible heat of about 800 ° C. in the nascent stage. However, in view of the fact that the sensible heat is not effectively used by the quenching process by spraying ammonia water, the effective use of this sensible heat COG as a technology
The present invention relates to a new thermal energy recovery technology / energy saving technology that converts a thermal energy into a light chemical substance by introducing a chemical reaction into.

Although the current crude coke oven gas treatment technology is positioned as a basic technology that forms the basis of the so-called coal tar chemical industry, mainly for recovering useful chemical components such as coal tar and light oil, heavy carbonization. From a future perspective on the commercial value of hydrogen components, supply and demand balance, international competitiveness with the petrochemical industry, etc., the business structure based on current technology is
It is hard to think that it has been stable over the long term. Rather, in addition to the development of renewable energy such as solar cells and wind power generation, while global environmental problems are mainly taken up mainly by the problem of global warming due to carbon dioxide,
A long-term vision for a hydrogen energy society centered on hydrogen as a clean fuel that does not release carbon dioxide during combustion has been proposed, but this heavy hydrocarbon contained in crude COG is used as a highly efficient, inexpensive, and stable source of hydrogen. Rethinking is considered to be one of the main options for business structure transformation that should be considered in the future. Therefore, the technology of the present invention aiming at the conversion of heavy hydrocarbons contained in crude COG into sensible heat and highly efficient light hydrocarbons (finally hydrogen) is also a new energy creation technology.

[0003]

2. Description of the Related Art As a technique for recovering sensible heat of crude COG generated from a coke oven, a method mainly including indirect heat recovery has been proposed. For example, in JP-B-59-44346 and JP-A-58-76487, a heat transfer tube is provided inside the riser of the coke oven, or between the riser section and the air collecting section, and heat is transferred inside the heat transfer tube. A method of circulating a medium to recover sensible heat is disclosed. However, by these methods, tar, light oil, etc. accompanying the COG generated on the outer surface of the heat transfer tube are attached, carbonized and
It is inevitable that densification will progress due to aggregation, and that the heat transfer efficiency with time and the heat exchange efficiency will decrease. As a technology to solve these problems, catalysts such as crystalline aluminum silicate and crystalline silica are applied to the outer surface of the heat transfer tube, and deposits such as tar are decomposed into low molecular weight hydrocarbons through the catalyst to improve heat transfer efficiency. Japanese Patent Application Laid-Open No. 8-134456 discloses a method for stably maintaining the temperature. However, this method also goes beyond the indirect heat recovery technology of crude COG sensible heat, and does not consider the quality of decomposition products of heavy hydrocarbons such as tar. Furthermore, the influence of reduction of decomposition activity over time due to catalyst poisoning sulfur compound components such as H ₂ S contained in crude COG has not been examined.

From the viewpoint of the quality of energy, the effective energy rate of thermal energy greatly changes depending on temperature, and decreases as the temperature becomes lower. It is also difficult to store. Therefore, even if the heat is indirectly exchanged and converted to high-temperature steam, the value of the recovered steam depends on the local electric power and steam balance of the heat source. On the other hand, the energy possessed by a chemical substance is characterized in that the effective energy rate is stable at a high level and is highly storable, though it depends on the usage form.

Regarding the so-called chemical energy conversion technology of thermal energy, which converts thermal energy whose quality greatly changes with temperature into chemical energy, a combined system of a gas turbine combined cycle power generation (GTCC) and another plant has been proposed. For example, in combination with oxygen production using a high temperature oxygen transporting solid electrolyte (for example, USP-551635
9), Steam reforming of natural gas using sensible heat of exhaust gas from gas turbine, hydrogen production and its fuel utilization (JP 2000-54852
No. gazette) etc. In both technologies, air and natural gas are made to act through a solid electrolyte and a functional material such as a catalyst,
It is converted into chemical energy such as oxygen and hydrogen.

No technique has been found for directly introducing a chemical reaction into a reactive gas generated at high temperature by utilizing its sensible heat to convert it into chemical energy, and conventionally, the sensible heat of the high temperature gas is indirectly recovered ( In most cases, the cooled gas is used after various treatments.

[0007] The synthesis gas production technology by reforming reaction using natural gas as a raw material has been put to practical use in methanol, FT (Fischer-Tropsch) synthetic oil, dimethyl ether production plant and the like. Catalytic steam reforming, non-catalytic oxygen introduction partial oxidation, and catalytic autothermal reforming are in the practical stage, but recently, the development of a membrane reactor using a mixed conductive solid electrolyte of oxygen ions and electrons has been vigorously pursued. Have been implemented, and the possibility of a significant reduction in the cost of producing syngas has been suggested (for example, “Ion transport membrane technolo”).
gy for oxygen separation and syngas production ”,
Solid State Ionics, 134, 21-33 (2000)).

In any case, in the reforming reaction using a catalyst, it is necessary to remove sulfur compounds as a catalyst poisoning component in the raw material natural gas in advance, and it is reported that 0.1 ppm or less is preferable (for example, , “Production of Hydrogen by Naphthus Steam Reforming” Petroleum and Petrochemistry, Vol.21, No.1
0).

In the case of crude COG, the sulfur compound content is 2000 p
It is considered to be extremely unlikely from the viewpoint of catalytic reaction design, but if desulfurization pretreatment is performed according to conventional catalytic reaction design, condensation of heavy hydrocarbon components due to temperature drop,
A decrease in reaction activity occurs and it is difficult to proceed with the target decomposition reaction. In addition, equipment costs are high, and it becomes difficult to secure economic rationality.

[0010]

The present invention focuses on the sensible heat of the crude COG and combines it with the high chemical reaction activity of the chemical substances contained in / associated with the crude COG due to the high temperature generation period. The objective is to construct a crude COG treatment method and treatment system for chemical energy conversion in which substances are converted to a fuel composition mainly composed of clean gas such as methane and hydrogen.

[0011]

In the present invention, the coal carbonization gas at the nascent stage has high quality sensible heat due to high temperature, high reaction activity, and further hydrogen (about 50% by volume). ),
We focused on the high concentration of methane (about 30% by volume).
Hydrogen not only functions as a hydrocracking medium but also
Sulfur compounds (about approx.
(2000ppm) also acts as a desulfurization medium. Also, methane is
It is expected to increase in use as clean gas energy, and is also regarded as the ultimate raw material for hydrogen (hydrogen generation by reforming reaction), which is regarded as the ultimate clean fuel.

By making full use of the characteristics of these crude COGs and creating light clean energy such as methane and hydrogen and supplying them to a wide area, solid polymer fuel cells are being actively developed as a distributed high efficiency power generation technology. It can be used as fuel for a wide range of benefits. Also, if used as fuel in the steelmaking plant, it will result in energy saving and reduction of carbon dioxide emission of the steelmaking plant.

Once the solid and liquid chemical substances accompanied by gas such as tar and light oil are cooled and recovered, the reaction activity is frozen due to the temperature history in the cooling process, and the polymerization reaction, etc. which induces the decrease of the reaction activity. Is often difficult to handle. When these cooled heavy hydrocarbons are heated again and gasified, there is a problem of carbon precipitation in the temperature rising process, a large amount of energy needs to be input, and capital investment becomes excessive, resulting in heavy carbonization. The economic and energy efficient barriers to the gasification and effective use of hydrogen will increase.

These heavy hydrocarbons are rich in reaction activity under high temperature conditions in the nascent stage, but especially in the case of COG, the hydrogen content is large because of the coal carbonization product gas, and this hydrogen is decomposed and lightened by heavy hydrocarbons. Promotes hydrocarbon conversion reaction. In addition, since steam also accompanies COG, steam reforming and hydrogen production reactions also proceed. Catalytic reaction design is a core technology for advancing these reactions stably and with high efficiency.

In order to study the possibility of the catalytic decomposition reaction progressing without the prior desulfurization treatment, various commercially available catalysts, solid solutions in which Ni was finely deposited on the surface, and solid phase crystallization catalysts were prepared and the results of experiments were conducted. It was found that the Ni-based catalyst has high reaction activity, suppresses the effect of poisoning by sulfur compounds in the temperature range of 600 ° C or higher, and the decomposition reaction proceeds, and the decomposition product is almost methane. Further, it was also found that the introduction of water vapor suppresses the reduction of the catalytic activity at a temperature of 900 ° C. or higher and the reforming of methane produced / hydrogen production reaction proceeds, thus completing the present invention.

In the present invention, the CO
Utilizing the high temperature activity of G, hydrocracking light hydrocarbon production,
It proposes a consistent reaction process up to the production of reformed synthesis gas (hydrogen, carbon monoxide), and provides options for using clean energy within the steelmaking plant and for wide-area supply, depending on the local circumstances where the coke oven is located. It is supposed to be possible.

The gist of the present invention is as follows. (1) A method for treating a crude coke oven gas, characterized in that a heavy hydrocarbon accompanied with a high temperature crude coke oven gas generated from a coke oven is decomposed by a catalyst to be converted into a light hydrocarbon. (2) The method for treating crude coke oven gas according to (1), wherein the catalyst is one or more selected from a hydrocracking catalyst, a steam reforming catalyst, and a hydrodesulfurization catalyst. (3) The main component of the light hydrocarbon is methane (1) or
The method for treating crude coke oven gas according to (2). (4) The crude coke oven gas treatment method according to any one of (1) to (3), wherein the crude coke oven gas containing light hydrocarbons is further partially oxidized and reformed to be converted to synthesis gas. (5) The crude coke oven gas treatment method according to (4), wherein the main component of the synthesis gas is hydrogen. (6) A crude coke oven gas treatment system, characterized in that a catalytic reactor is arranged in the coarse coke oven gas flow path from the coke oven to the heat recovery device. (7) The catalytic reactor is a low-pressure loss honeycomb type monolith catalyst carrier, a honeycomb type stainless metal catalyst carrier, or a heat exchanger type tube wall catalytic reactor (6) crude coke oven gas treatment system . (8) The catalyst used in the catalytic reactor is one or more selected from hydrocracking catalyst, steam reforming catalyst and hydrodesulfurization catalyst (6) or treatment of crude coke oven gas according to (7) system. (9) The crude coke oven gas treatment system according to (6) to (8), further comprising a membrane reactor installed between the catalytic reactor and the heat exchanger. (10) The crude coke oven gas treatment system according to (9), wherein the membrane reactor is a membrane reactor having an oxygen ion / electron mixed conductive solid electrolyte membrane and a hydrocarbon reforming catalyst layer.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

FIG. 1 is an example of a consistent process from coke oven to hydrogen recovery. This process incorporates an oxygen ion / electron mixed conductive solid electrolyte membrane reactor, and when it is installed in the hydrogenolysis gas (methane-rich COG) channel of crude COG, it continuously contains methane. Partial oxidation reforming is used to produce synthesis gas, and if it is not installed in the flow path, it will function as an oxygen enricher by itself and regenerate the catalyst layer.
Used for (burn-off of catalyst deposits) and according to oxygen needs in ironmaking plants. In any case, the sensible heat of COG after the reaction is recovered by a heat storage type heat exchanger and a waste heat recovery boiler, and used for steam production and air preheating.

COG is introduced into the catalytic reactor through the ascending pipe in the upper part of the coke oven shown in FIG. Catalytic reactors include heavy hydrocarbon hydrocracking catalysts (Ni-based, iron-based, aluminosilicate-based), steam reforming catalysts (Ni-based), hydrodesulfurization catalysts (CoMo
The system) is used alone or as a mixture, and in some cases steam is introduced to allow the reaction to proceed. Here, since the coke oven gas system is operated under reduced pressure suction, a catalytic reactor with pressure loss is not preferable, and a honeycomb type carrier (ceramics, SUS-based metal) generally used as an automobile exhaust gas purification facility is used. A carrier carrying a predetermined catalyst (low-pressure loss honeycomb type monolith catalyst carrier, honeycomb type stainless steel metal catalyst carrier), or a heat recovery type reactor (heat exchanger type tube wall) carrying a catalyst on the outer surface of the heat exchanger. A catalytic reactor) is preferred. Further, as the catalyst, a Ni-based catalyst having high decomposition activity and high reforming reaction activity is desirable. Furthermore, the sulfur compound poisoning resistance is high, and sintering does not occur when burning off foreign matter adhering to the catalyst surface. A catalyst whose surface structure is controlled so that the catalytic activity can be recovered, for example, Ni
Is a solid solution catalyst deposited on the surface from the inside of the carrier in the form of nanoclusters (for example, Ni _x Mg _1-x O), a solid phase crystallization method catalyst (for example,
Ni _x Ba _1-x TiO ₃ ) is preferred.

The reaction of heavy hydrocarbons associated with crude COG is complicated and includes steam reforming, steam dealkylation, hydrocracking, hydrodealkylation, dry reforming (carbon dioxide reforming),
Control is considerably difficult because a wide variety of reactions such as thermal decomposition and carbon deposition are expected. When the hydrogenolysis progresses and the hydrogen concentration in the atmosphere decreases, the carbon precipitation / hydrogen generation reaction is promoted, leading to a decrease in catalytic activity. On the other hand, when steam is introduced, the steam reforming reaction of the hydrocracking product is promoted, hydrogen and carbon monoxide are generated, and a part of carbon monoxide generates hydrogen and carbon dioxide by the water gas shift reaction. . Taking into consideration the facility restrictions of the reactor and the required gas composition,
Although it is necessary to select reaction conditions, the composition of crude COG varies greatly depending on the coal type, coke oven operating conditions, and progress of carbonization.Therefore, a method of controlling by introducing steam and / or oxygen into the catalytic reactor. Is simple. In order to have a degree of freedom in temperature control, the outer wall catalyst coating heat exchanger type catalytic reactor (heat exchanger type tube wall catalytic reactor) is used as the reactor type.
Is preferred.

Crude COG obtained by converting hydrocarbons such as associated coal tar and light oil into light hydrocarbons mainly composed of methane has condensable components converted into light hydrocarbons, so that sensible heat is generated in existing heat exchange equipment. It is possible to collect. Partial oxidation in succession,
When reforming, before entering the heat exchange equipment, it is introduced into a membrane reactor with small pressure loss, and part of the sensible heat is used to convert chemical energy into synthesis gas (hydrogen, carbon monoxide). It
When the supply and demand balance of hydrogen or syngas is not tight, the membrane reactor is bypassed and introduced into heat exchange equipment to recover sensible heat. If there is a hydrogen external sales market and the hydrogen supply-demand balance is tight, use a membrane reactor to
After passing through the heat exchange facility, the gas is purified through the existing gas treatment plant and subsequently introduced into the water gas shift reactor, and the contained carbon monoxide is converted into hydrogen by the water gas shift reaction (CO + H ₂ O → H ₂ + CO ₂ ) High-purity hydrogen is recovered through the carbon dioxide absorption tower and sent to external sales.

The overall configuration of these reaction systems has different optimal solutions depending on the local energy situation where the coke oven is located. Therefore, it is preferable to disassemble each element process and maintain a high degree of design freedom.

The principle diagram of the solid electrolyte membrane type reactor is shown in FIG. 2 by taking the reaction of methane as an example. There are various discussions about the basic scheme of the partial oxidation reforming reaction of methane, and the theory that the partial oxidation reforming (CH ₄ + 1 / 2O ₂ → 2H ₂ + CO) proceeds in one step, Complete combustion (CH ₄ + 2O ₂
→ 2H ₂ O + CO ₂ ) progresses, and then methane reforming reaction by generated steam and carbon dioxide (CH ₄ + H ₂ O → 3H ₂ + CO, CH ₄ + CO ₂ → 2H
There is a theory that proposes an indirect reaction mechanism that ₂ + 2 CO) progresses. FIG. 2 schematically shows the latter indirect reaction mechanism as a base.

In this reactor, a hydrocarbon reforming catalyst is applied to the permeate side of an oxygen ion / electron mixed conductive solid electrolyte membrane, so that oxygen permeated in an ionic state at high temperature (800 to 1000 ° C.) By utilizing high activity, it is possible to realize both high reaction yield and partial oxidation reforming reaction selectivity.

FIG. 3 shows an example of the shape of a solid electrolyte membrane molded into a one-end sealed tubular membrane, and FIG. 4 shows an example of a solid electrolyte membrane piece reactor in which a large number of such tubular membranes are integrated. Although it depends on the oxygen ion permeation ability of the solid electrolyte, it is better to coat on a porous support tube to form a thin film, because the oxygen ion permeation resistance is reduced and the oxygen ion permeation amount can be improved, which is advantageous for compact equipment. Is. However, when used as a reactor, since oxygen disappears due to the reaction, the oxygen concentration ratio through the membrane can be increased, and the permeation amount of oxygen ions can be significantly improved as compared with oxygen separation applications. In consideration of the mechanical strength of the solid electrolyte, the resistance to the reaction gas atmosphere, etc., the film thickness, use as a dense tube without a supporting tube, etc. are determined.

[0027]

EXAMPLES The present invention will be described below with reference to examples.

(Example) Method for Preparing Hydrogenated Light Hydrocarbon Conversion Catalyst (1) Ni _x Mg _1-x O Solid Solution Catalyst Preparation Nickel acetate (Ni (CH ₃ COO) ₂ ) and magnesium nitrate (Mg (N
O ₃ ) ₂ ), prepare a mixed aqueous solution (total metal concentration: 0.5 mol / l) so that the molar ratio of Ni: Mg is 1: 9, and add potassium carbonate (K ₂ CO ₃ ) as a precipitant. While aging, the mixture was aged at 60 ° C for 1 hour. After the formed precipitate was dehydrated and washed, silica sol (Cataloid S-20L manufactured by Asahi Kasei Co., Ltd.) as a binder was added to the Si in the catalyst.
O ₂ was added in an amount of 50% by mass. Using this, water was added to form a slurry for spray-drying a catalyst stock solution.

Also, commercially available Ni-based catalysts, alumina-based catalysts, Co
The Mo-based hydrodesulfurization catalyst was crushed and the particle size was adjusted, and used alone or as a mixture.

(2) Preparation of Ceramic Honeycomb Monolith Catalyst A honeycomb carrier having a composition ratio of kaolinite and montmorillonite of 3: 1 was prepared by a slurry extrusion method. The shape is diameter: 18 mm, length: 15 mm, channel size: 1.8 mm square, wall thickness: 0.5 mm, surface area measurement by BET method is 20 m ² /
The result was 0.12 cm ³ / g in terms of g and pore volume measurement.

The monolith carrier was sprayed with the catalyst solution for spray drying described in (1) above, heated to 950 ° C. for 3 hours, and then calcined for 20 hours. The coating amount was 10% by mass, and the coating thickness was 60 μm, which was the amount of catalyst supported.

(3) Design of coal pyrolysis gas decomposition experiment system A fixed bed two-stage reactor was used for the coal pyrolysis gas decomposition experiment. The reaction tube is made of quartz with an inner diameter of 20 mm and a length of 900 mm.
Two electric furnaces (length 300 mm) were used to heat the reaction tube. Two upper and lower dispersion plates were provided in the reaction tube, and the reaction tube was set so that each dispersion plate was installed in the central portion of the electric furnace.
The upper part of the reaction tube was filled with coal particles, and the lower part of the reaction tube was filled with the ceramic honeycomb monolith catalyst described in (2) above.
The pyrolysis temperature of coal and the temperature of the catalyst layer were controlled by controlling the two electric furnaces independently.

The experiment was conducted as described below.

Approximately 1 g of a coal sample (Witbank charcoal was crushed and sieved to 12-32 mesh) was placed on the upper dispersion plate, and the ceramic honeycomb monolith catalyst was placed on the lower dispersion plate, followed by nitrogen gas. Sufficiently replaced the inside of the system. After raising the temperature of the catalyst layer to a predetermined temperature, a reaction gas was flown. After the system was stabilized, the coal sample was heated at a heating rate of 10 ° C / min to start the thermal decomposition experiment. After heating was started, the produced gas was sampled approximately every 150 ° C. and analyzed by gas chromatography. After the coal sample reached a predetermined temperature (typically 1000 ° C.), it was switched to nitrogen gas and the temperature was lowered. After cooling, the pyrolysis residue char and the catalyst were recovered. The carbon content deposited in the reaction tube and the tar content adhering to the lower part of the reaction tube were combusted with oxygen, and the carbon dioxide and carbon monoxide in the flue gas were analyzed by gas chromatography. The carbon content deposited on the catalyst was also measured by burning with oxygen. Nitrogen (100%), hydrogen
/ Nitrogen (50/50) was supplied to adjust the decomposition reaction atmosphere, and the supply amount was 1 ml (STP) / min in all decomposition experiments. Use a micro feeder to supply water vapor of 0 to 4 ml (S
It was adjusted to TP) / min and supplied together with the atmosphere-adjusting gas. The decomposition reaction temperature was set in the range of 600 to 900 ° C.

(4) Coal carbonization gas decomposition experiment result Coal carbonization independent experiment was conducted, and coke yield was 70% and gas yield was 3%.
The volume% of major components in 10 ml / g, coal and gas is hydrogen 56.2.
%, Methane 28.1%, carbon monoxide 5.6%, carbon dioxide 1.0%.

Next, the production of associated hydrocarbons such as tar is continuously conducted.
A decomposition experiment was conducted. The catalytic activity is Ni _0.1Mg_0.9O solid solution
Medium> Ni-based commercial catalyst (IC / Ni / Al₂O₃Catalyst, 46-1P, including Ni
30% by mass, 32-60 mesh)> Active Al₂O₃(12-32 Messi
)> Fe / Al₂O₃Of catalyst (Fe content 5% by mass, 12-32 mesh)
It was in order. When there is no catalyst, there is a large amount of black at the bottom of the reaction tube.
Adhesion of tar-like substances was observed, but when the catalyst was loaded,
In that case, it was observed that the deposits were significantly reduced. Special
In addition, Ni-based catalysts show high decomposition activity,
No tar-like substance was observed at all.
On the other hand, in the case of other catalysts, the adhesion of yellow oily substance was observed.
Was given.

The decomposition reaction activity slightly changes depending on the temperature,
The maximum yield of methane was in the range of 650 ℃ to 750 ℃, and the maximum concentration of methane was 60% by volume.

Next, an experiment was conducted for the purpose of actively introducing a steam reforming reaction accompanied by steam. The catalytic activity was the same as in the case of the decomposition reaction, the highest was that of Ni _0.1 Mg _0.9 O solid solution catalyst, and the gas flow rate was increased 2.4 times and 2.8 times that of hydrogen in the reaction at 900 ° C. On the other hand, almost no change was observed in the amount of methane. It is not clear whether the heavy hydrocarbon was decomposed into hydrogen and carbon monoxide by the direct steam reforming reaction, or whether the steam reforming reaction of methane proceeded through decomposition and methane generation. The final main gas volume composition is hydrogen 68.2%, methane 10.8%, carbon monoxide 19.2%,
Carbon dioxide was 1.3%. On the other hand, when using a commercially available Ni-based catalyst, the amplification of the gas flow rate was only 1.9 times under the same conditions,
A 1.7-fold amplification of methane was observed. On the other hand, the amplification of hydrogen stopped at 1.9 times. That is, in the case of a commercially available Ni-based catalyst, although the decomposition / methane production reaction proceeds, the steam reforming reaction activity of methane is assumed to be lower than that of the solid solution catalyst. As a cause, it was assumed that the contained sulfur compounds would inhibit the steam reforming reaction activity.Therefore, a simulated gas consisting of 55% by volume hydrogen, 30% by volume methane, and 20% by volume nitrogen was prepared, and hydrogen sulfide was added at 2019 ppm. When a steam reforming experiment was conducted under the same reaction conditions, the addition rate of methane was
While it was 50%, it was about 10% with the commercially available catalyst.

In the result of observation of the catalytic reaction tube after the completion of the steam-associated decomposition reaction experiment, no tar-like substance was observed in the Ni-based catalyst regardless of the experimental temperature. On the other hand, in the case of other catalysts, deposition of black deposits was observed.

(5) Method for Preparing Oxygen Ion / Electron Mixed Conductive Solid Electrolyte Membrane Various methods for preparing porous ceramics and coating a solid electrolyte thin film are known, and Japanese Patent Application No. 10-15790.
Also in JP-A-5, a porous body is prepared with yttria-stabilized zirconia, and a pore size adjusting pretreatment is performed, and then a Sr ₂ Fe ₃ O _6.25 thin film is formed by a metal organic chemical vapor deposition method. An example in which it was formed by a metal chemical vapor deposition method and subjected to a partial oxidation reaction of methane has been reported.

In the present invention, oxygen-deficient perovskite having a composition of Sr _1.7 La _0.3 Ga _0.6 Fe _1.4 O _5.5 , which is considered to have excellent resistance to a partially oxidizing atmosphere, is powdered with SrO, La ₂ O ₃ , GaO ₂ , and Fe ₂ O ₃ powder. Was pulverized and mixed in a stoichiometric ratio, calcined and then pulverized, compacted into a disk shape, and subjected to a partial oxidation experiment. The outer diameter of the disk is 20 mm, the thickness is 1.5 mm, and it is a dense sintered body, and the catalyst is
Commercially available Ru-based catalyst (RUA catalyst manufactured by Toyo CCI Co., Ltd., natural gas steam reforming catalyst) was sized to 10 μm or less, and then added with an organic solvent to form a slurry, which was applied to the surface of the solid electrolyte dense sintered body and dried. After that, it is baked at 850 ° C, or a commercial catalyst is
After preparing to 40 mesh, apply it to the surface of the solid electrolyte dense sintered body.
Carried. The catalyst mass was 32 mg and 900 mg, respectively.

(6) Oxygen Permeation Coefficient Measurement, Methane Gas Partial Oxidation Reaction Measurement Reaction pressure: normal pressure, temperature: 850 ° C., supply air amount 150 ml / min, supply methane amount: 30 ml / min, and methane partial oxidation experiment was conducted. . In the case of the slurry-coated catalyst, the reaction conversion rate and the selectivity tended to be low due to the small amount of supported catalyst, but in the case of the granular supported catalyst, the methane conversion rate was 80%, H ₂ / CO =
2 and the partial oxidation reaction chemistry ratio were obtained, and it was found that the selectivity was excellent. The oxygen permeation flow rate is 9 ml (STP) / m
A high and stable value of in · cm ² was obtained.

Assuming that the raw COG is a heavy hydrocarbon converted to a light hydrocarbon mainly composed of methane, the raw material gas is supplied in the range of methane concentration of 10 to 90% by volume and hydrogen of 30 to 80% by volume. After preparation, a partial oxidation reaction experiment was performed under the same reaction conditions as above. Compared to 100% of methane, the hydrogen oxidation reaction proceeds, but the generated steam functions as a steam reforming medium for methane, and the conversion rate of methane is 70-90%, H ₂ /CO=1.7-2.0, which is a high reaction conversion rate. And selectivity was obtained. Also, the oxygen permeation flow rate is
A stable value of 7 to 13 ml (STP) / min · cm ² was obtained.

Based on the above basic data, it was estimated that the sensible heat of crude COG, the light hydrocarbons using the associated heavy hydrocarbons, and the increase in the calorific value of COG due to the synthesis gas conversion were 15 to 28%.

[0045]

EFFECTS OF THE INVENTION The present invention focuses on the fact that the heavy hydrocarbons associated with the coke oven gas have a high reaction activity during the high temperature generation period, and utilizes the fact that the gas contains a large amount of hydrogen. The present invention provides a technique for stably promoting a catalytic cracking reaction of heavy hydrocarbons mainly composed of hydrocracking and converting methane into light hydrocarbons mainly composed of methane.
It also provides a technique for efficiently converting the produced light hydrocarbons into a synthesis gas mainly containing hydrogen by a partial oxidation reforming reaction by continuously passing the solid electrolyte membrane reactor.

By carrying out the present invention, CO
The sensible heat possessed by G and the associated heavy hydrocarbons are combined with each other through a catalytic chemical reaction to realize a new energy-efficient energy-saving process for converting thermal energy into light chemical energy, and associated heavy carbonization. During the light chemical energy conversion process of hydrogen, the syngas mainly consisting of methane and hydrogen is amplified, so that it can be supplied over a wide area, and is widely supplied and used as a clean energy source for highly efficient new distributed power sources such as fuel cells. If so, carbon dioxide emissions can be reduced. Further, according to the present invention, the condensable heavy hydrocarbon such as coal tar is converted into a light chemical substance, so that stable heat recovery using the existing heat recovery technology becomes possible.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram of a COG processing system of the present invention.

FIG. 2 is a schematic diagram of synthetic gas production by a partial oxidation reaction of methane in COG in an oxygen ion / electron mixed conductive solid electrolyte membrane.

FIG. 3 is a schematic view of a reaction tube incorporated in an oxygen ion / electron mixed conductive solid electrolyte membrane reactor.

FIG. 4 is a schematic diagram of the internal structure of an oxygen ion / electron mixed conductive solid electrolyte membrane reactor.

Continued front page    (72) Inventor Kenichiro Fujimoto             20-1 Shintomi, Futtsu City Nippon Steel Co., Ltd.             Inside the surgical development headquarters (72) Inventor Hideki Kurimura             1-131 Hatagaya, Shibuya-ku, Tokyo Empire             Petroleum Co., Ltd. (72) Inventor Shoichi Kaganoi             1-131 Hatagaya, Shibuya-ku, Tokyo Empire             Petroleum Co., Ltd. (72) Inventor Yohei Suzuki             1-131 Hatagaya, Shibuya-ku, Tokyo Empire             Petroleum Co., Ltd. F-term (reference) 4G040 EA03 EA06 EB14 EB23 EB32                       EB44 EC08                 4G069 AA03 AA08 BA06B BB06B                       BC10B BC68B CC07 CC22                       DA06 EA19 FA02 FB09                 4H060 AA01 BB08 CC03 CC18 DD03                       EE03 FF02 GG02

Claims (10)

[Claims] 1. A method for treating crude coke oven gas, characterized in that heavy hydrocarbons accompanying high temperature crude coke oven gas generated from a coke oven are decomposed by a catalyst to be converted into light hydrocarbons. 2. The method for treating crude coke oven gas according to claim 1, wherein the catalyst is at least one selected from a hydrocracking catalyst, a steam reforming catalyst, and a hydrodesulfurization catalyst. 3. The method for treating crude coke oven gas according to claim 1, wherein the light hydrocarbon is mainly composed of methane. 4. The method for treating crude coke oven gas according to claim 1, wherein the crude coke oven gas containing light hydrocarbons is further partially oxidized and reformed to be converted into synthesis gas. 5. The method for treating crude coke oven gas according to claim 4, wherein the main component of the synthesis gas is hydrogen. 6. A crude coke oven gas treatment system comprising a catalytic reactor arranged in a crude coke oven gas passage to a heat recovery device from the coke oven. 7. The crude coke oven gas according to claim 6, wherein the catalytic reactor is a low pressure loss honeycomb type monolith catalyst carrier, a honeycomb type stainless steel metal catalyst carrier, or a heat exchanger type tube wall catalytic reactor. Processing system. 8. The treatment of crude coke oven gas according to claim 6, wherein the catalyst used in the catalytic reactor is at least one selected from hydrocracking catalysts, steam reforming catalysts and hydrodesulfurization catalysts. system. 9. The crude coke oven gas treatment system according to claim 6, further comprising a membrane reactor provided between the catalytic reactor and the heat exchanger. 10. The crude coke oven gas treatment system according to claim 9, wherein the membrane reactor is a membrane reactor having an oxygen ion / electron mixed conductive solid electrolyte membrane and a hydrocarbon reforming catalyst layer.