KR20200062701A - Method for Preparing synthetic Natural Gas Having Improved Caloric Value and Systems for the Same - Google Patents

Abstract

The present invention relates to a method for preparing synthetic natural gas having improved caloric value, and more particularly, to a method for preparing synthetic natural gas, in which synthetic natural gas having a calorific value increased by more than 10,400 kcal/Nm^3 from coal, biomass, solid carbon fuel, and the like is provided without additional supplementation of hydrocarbons from the outside, thereby being economical and environmentally friendly, and the selectivity of lower-grade hydrocarbons of C4 or less for regulating the calorific value of synthetic natural gas in a synthetic natural gas production process is increased, thereby preparing the synthetic natural gas of a high calorific value without additional separation and purification and upgrading processes for hydrocarbons of C5 or higher.

Description

Method for preparing synthetic natural gas and improved caloric value and systems for the same

The present invention relates to a method for manufacturing a synthetic natural gas having an increased calorific value and a manufacturing system thereof, and more particularly, to a method for producing a high calorific synthetic natural gas capable of efficiently producing synthetic natural gas with an increased calorific value from synthetic gas. And its manufacturing system.

In the case of coal among fossil fuels, research has been actively conducted to convert coal to Synthetic Natural Gas (SNG) worldwide due to its rich reserves and less local ubiquity compared to other resources. Coal gasification (Coal Gasification) refers to a technology that gas is used to generate synthetic gas (H ₂ , CO) by gasifying it with high heat. When coal is subjected to high heat, it changes in the order of solid, liquid and gas.

However, synthetic gas alone does not reach the heat of natural gas, so synthetic gas is methaneized to produce synthetic natural gas. However, since synthetic natural gas mainly contains methane (90% ~ 98%), even if purified, the calorific value is about 9,400 kcal/m ³ , which is less than 10,400 kcal/m ³ , the standard heat value of natural gas designated by the Korea Gas Corporation. It is difficult to utilize synthetic natural gas, and accordingly, a method for improving heat generation is required.

In this regard, conventionally, a calorific adjustment process in which hydrocarbons C3, C4, etc. having a high calorific value is added to the synthetic natural gas is added, but this method takes a cost to purchase a separate hydrocarbon, and a storage space for the purchased hydrocarbon. There was a problem that additional equipment for adjusting the mixing ratio was required.

Specifically, in order to generate the calorific value of the synthetic natural gas to exceed the reference value of 10,400 kcal/m ³ , hydrocarbons of about 12.6% for ethane, about 6.35% for propane, and about 4.25% for butane must be added. The purchase cost of the hydrocarbon (C _n H _m ) as described above is close to about 20% of the total cost of syngas production. Therefore, if it is possible to increase the calorific value by converting some gases to hydrocarbons of high calorific value during the synthesis natural gas production process without external supplementation of such high calorific gas, it may be useful in related fields.

Accordingly, in Korean Registered Patent No. 1420634 (Patent Document 0001), Fischer produces C1 to C4 lower hydrocarbons in the production process of synthetic natural gas in order to produce sufficient amount of synthetic natural gas without the need to supplement a separate hydrocarbon. A method of producing a synthetic natural gas comprising a Fischer-Tropsch process and mixing C1 to C4 lower hydrocarbons produced in the Fischer-Tropsch process with methane synthesis gas obtained in a methane synthesis process And there has been disclosed a device for this, in Korean Patent Registration No. 1875857 (Patent Document 0002), the first Fischer-Tropsch reaction process and the second Fischer-Tropsch process during the production of synthetic natural gas (Fischer-Tropsch) A method for producing a high-calorie synthetic natural gas optimized in terms of hydrogen balance and energy efficiency of a final product including a reaction process has been disclosed.

In addition, in Korean Patent Publication No. 2018-0105823 (Patent Document 0003), a portion of the synthetic gas is produced to produce a synthetic natural gas having a high calorific value without mixing liquefied petroleum gas (LPG) supplied from the outside to the synthetic natural gas. Disclosed is a method and a manufacturing system for producing a hydrocarbon compound having a high calorific value by separating a Fischer-Truffsch reaction, and preparing a synthetic natural gas having an increased calorific value by mixing a hydrocarbon compound having a high calorific value with a synthetic natural gas.

However, all of the above-described methods and apparatuses for producing a high-calorie synthetic natural gas employ a Fischer-Tropsch reaction to produce hydrocarbons (C3, C4, etc.) having a high calorific value. Since the Fischer-Tropsch reaction is mostly produced with hydrocarbons of C5 or higher through a chain-chain growth reaction using synthetic gas (H ₂ and CO gas) as a raw material, Fischer-Treat is required to produce a high-calorie synthetic natural gas. In addition to the separation and purification process of the hydrocarbon compound produced in the Roppsch reaction, an additional upgrading process for conversion of C1 to C4 lower hydrocarbons from C5 or higher hydrocarbons such as hydrogenation and isomerization is required. There was a problem.

Therefore, it is produced with high-calorie hydrocarbons through its own production process without replenishment of external high-calorie gases, but it increases the selectivity of lower hydrocarbons of C4 or less of the produced hydrocarbons to separate or purify or upgrade separate C5 or higher hydrocarbon compounds. There is a need to develop a technology for producing synthetic natural gas having a high calorific value capable of controlling its own heat without a process.

Korean Registered Patent No. 1420634 (Notice: 2014.07.21) Korean Registered Patent No. 1875857 (Publication date: 2014.10.16) Korean Patent Publication No. 2018-0105823 (Publication date: 2018.10.01)

The main object of the present invention is to solve the above-mentioned problems, and by including a process of producing lower hydrocarbons of C4 or less in the process of producing synthetic natural gas, synthetic natural gas having high calorific value without supply of liquefied petroleum gas to the outside It is to provide a method for manufacturing a synthetic natural gas with an increased calorific value capable of producing gas and a system for manufacturing the same.

It is also an object of the present invention, by increasing the selectivity of lower hydrocarbons such as butane and propane, especially C4 or less, in the production process of synthetic natural gas, synthesis of sufficient calorific value without additional separation purification and upgrading process for C5 or higher hydrocarbons It is to provide a method for producing a synthetic natural gas with an increased calorific value capable of producing natural gas, and a manufacturing system thereof.

In order to achieve the above object, an embodiment of the present invention comprises the steps of (a) gasifying the fuel to obtain a syngas; (b) a first aqueous gas conversion step of converting the obtained synthesis gas into an aqueous gas conversion reaction; (c) a second water gas conversion step of separating a part of the synthesis gas obtained in the first water gas conversion step to perform a water gas conversion reaction; (d) a hydrocarbon synthesis step of separating a part of the synthesis gas obtained in the first water gas conversion step, and reacting a part of the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons; (e) a methane synthesis step of producing a methane-containing gas by methane synthesis reaction of the synthesis gas obtained in the second water gas conversion step; And (f) mixing C1 to C4 lower hydrocarbons produced in the hydrocarbon synthesis step with the methane-containing gas prepared in the methane synthesis step to produce a synthetic natural gas. Gives

In one preferred embodiment of the present invention, the fuel may be characterized in that at least one selected from the group consisting of coal, biomass and solid carbon.

In a preferred embodiment of the present invention, the volume ratio of CO:H ₂ contained in the synthesis gas obtained in step (b) may be characterized in that it is 1: 1-3.

In a preferred embodiment of the present invention, the volume ratio of CO:H ₂ contained in the syngas obtained in step (c) may be characterized in that it is 1:2 to 4.

In a preferred embodiment of the present invention, step (d) comprises (i) separating a portion of the synthesis gas obtained in the first water gas conversion step, reacting the separated portion of the synthesis gas in the presence of a methanol synthesis catalyst to methanol and / Or preparing a dimethyl ether-containing gas; And (ii) producing C1 to C4 lower hydrocarbons by reacting the prepared methanol and/or dimethyl ether-containing gas and a part of the synthesis gas obtained in the first aqueous gas conversion step in the presence of a hydrocarbon synthesis catalyst. Can be done with

In a preferred embodiment of the present invention, step (d) separates a part of the synthesis gas obtained in the first water gas conversion step, and a part of the separated synthesis gas is a mixed catalyst in which methanol synthesis catalyst and hydrocarbon synthesis catalyst are mixed. It may be characterized by reacting in the presence to produce C1 to C4 lower hydrocarbons.

In a preferred embodiment of the present invention, the methanol synthesis catalyst is characterized in that at least one selected from the group consisting of Cu-Zn-based catalyst, Pd-Z-Cr-based catalyst, Zn-Cr-based catalyst and Pd-based catalyst Can be.

In a preferred embodiment of the present invention, the hydrocarbon synthesis catalyst is Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir and Pr is one or more selected from the group consisting of a supported zeolite-based catalyst It can be characterized as.

In a preferred embodiment of the present invention, the mixed catalyst may be characterized in that the methanol synthesis catalyst and the hydrocarbon synthesis catalyst are mixed in a weight ratio of 4:1 to 1:4.

In a preferred embodiment of the present invention, after the step (e), the synthetic natural gas produced may be characterized in that the calorific value is 10,400 kcal/Nm ³ or more.

Another embodiment of the present invention is a gasification unit to obtain a synthesis gas by gasifying the fuel; A first aqueous gas conversion unit for converting the obtained synthesis gas into an aqueous gas conversion reaction; A second water gas conversion unit that separates a portion of the synthesis gas converted from water gas from the first water gas conversion unit to perform water gas conversion reaction; A hydrocarbon synthesis unit for separating a part of the synthesis gas converted into water gas from the first water gas conversion unit and reacting the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons; A methane synthesis unit for producing a methane-containing gas by methanation reaction of the synthesis gas converted from the water gas in the second water gas conversion unit; And a mixing unit for producing a synthetic natural gas by mixing C1 to C4 lower hydrocarbons produced in a hydrocarbon synthesis unit with the methane-containing gas.

In another preferred embodiment of the present invention, the fuel may be characterized in that at least one selected from the group consisting of coal, biomass and solid carbon.

In another preferred embodiment of the present invention, the volume ratio of CO:H ₂ contained in the first water gas-converted syngas may be 1: 1 to 3.

In another preferred embodiment of the present invention, the volume ratio of CO:H ₂ contained in the second water gas-converted syngas may be 1:2 to 4.

In another preferred embodiment of the present invention, the hydrocarbon synthesis unit separates a portion of the first water gas converted syngas and reacts the separated syngas in the presence of a methanol synthesis catalyst to produce methanol and/or dimethyl ether-containing gas. Methanol synthesis unit; And a hydrocarbon synthesis unit for producing C1 to C4 lower hydrocarbons by reacting the prepared methanol and/or dimethyl ether-containing gas with a portion of the first aqueous gas converted synthesis gas in the presence of a hydrocarbon synthesis catalyst. .

In another preferred embodiment of the present invention, the hydrocarbon synthesis unit separates a portion of the first water gas converted synthesis gas, and reacts the separated synthesis gas in the presence of a mixed catalyst in which methanol synthesis catalyst and hydrocarbon synthesis catalyst are mixed to C1. To C4 lower hydrocarbons.

In another preferred embodiment of the present invention, the methanol synthesis catalyst is characterized in that at least one selected from the group consisting of Cu-Zn-based catalyst, Pd-Zn-Cr-based catalyst, Zn-Cr-based catalyst and Pd-based catalyst Can be.

In another preferred embodiment of the present invention, the hydrocarbon synthesis catalyst is Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir and Pr is one or more selected from the group consisting of a supported zeolite-based catalyst It can be characterized as.

In another preferred embodiment of the present invention, the mixed catalyst may be characterized in that the methanol synthesis catalyst and the hydrocarbon synthesis catalyst are mixed in a weight ratio of 4:1 to 1:4.

According to the present invention, it is economical and environmentally friendly at the same time as it is possible to provide synthetic natural gas having an increased calorific value per unit volume of 10,400 kcal/Nm3 or more from coal, biomass, solid carbon fuel, etc. without supplementing hydrocarbons from the outside. It has a phosphorus effect.

In addition, according to the present invention, by increasing the selectivity of lower hydrocarbons of C4 or less for adjusting the amount of heat of the synthetic natural gas in the production process of synthetic natural gas, additional separation and purification for C5 or more hydrocarbons and the burden on the upgrade process While lowering, there is an effect that can produce a high-calorie synthetic natural gas.

1 is a schematic diagram of a method of manufacturing a synthetic natural gas with increased calorific value according to an embodiment of the present invention.
2 is a schematic diagram of a method of manufacturing a synthetic natural gas with increased calorific value according to another embodiment of the present invention.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

When a certain part of the present specification “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

Throughout the present specification, the number after the letter C refers to the number of carbon atoms in the hydrocarbon compound, and the C2 hydrocarbon compound refers to a hydrocarbon compound having two carbon atoms.

In one aspect, the present invention, (a) gasifying a fuel to obtain a synthesis gas; (b) a first aqueous gas conversion step of converting the obtained synthesis gas into an aqueous gas conversion reaction; (c) a second water gas conversion step of converting the synthesis gas obtained in the first water gas conversion step into a water gas conversion reaction; (d) a hydrocarbon synthesis step of separating a part of the synthesis gas obtained in the first water gas conversion step, and reacting a part of the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons; (e) a methane synthesis step of producing a methane-containing gas by methane synthesis reaction of the synthesis gas obtained in the second water gas conversion step; And (f) mixing C1 to C4 lower hydrocarbons produced in the hydrocarbon synthesis step with the methane-containing gas prepared in the methane synthesis step to produce a synthetic natural gas. It is about.

More specifically, the present invention relates to a method for producing a synthetic natural gas (high caloric SNG) having an increased calorific value using syngas obtained from fuels such as coal, biomass, and solid carbon. The method relates to a method of synthesizing a hydrocarbon having a high calorific value by separating a portion of the synthetic gas in which the ratio of carbon monoxide and hydrogen is controlled, and mixing it with a synthetic natural gas to produce a synthetic natural gas having a calorific value of liquefied natural gas. At this time, the hydrocarbon having a high calorific value efficiently increases the selectivity of hydrocarbons of C4 or less, particularly butane and propane, by using a methanol synthetic catalyst and a hydrocarbon synthetic catalyst in the process of synthesizing natural gas. Can be produced.

1 schematically shows one embodiment of the present invention, and FIG. 2 schematically shows another embodiment of the present invention. Referring to FIGS. 1 and 2, the method of the present invention will be described in more detail. It can be prepared in a synthesis gasification step [S10, (a) step] of gasifying coal, biomass, and solid carbon as fuel. At this time, oxygen and water or water vapor are used as gas fires to convert the fuel into carbon monoxide and hydrogen by a reaction as shown in the following reaction formula 1. The oxygen needed for the syngasification step can be obtained from the air, but can be obtained in an oxygen separation process that separates nitrogen. Thus the synthesis gas obtained is CO: are obtained as a 1: 1 volume ratio of H _2.

[Scheme 1]

CO + H ₂ O → CO ₂ + H ₂ (-9.5 kcal/gmol)

Synthesis gas having a volume ratio of CO 1: H ₂ produced in this way is about 1: 1 is additionally subjected to a synthesis gas purification step (S20), and in the synthesis gas purification step (S20), dust collection and H ₂ S, CO _2, etc. Acid gas separation and the like may be performed. Specifically, a separation method through an absorbent, a method such as an amine method can be used, but is not limited thereto, and any method that can be used for the same purpose in the related industry can be used without limitation.

As described above, the synthesis gas that has undergone the synthesis gas refining step (S20) must be adjusted in volume ratio of CO:H ₂ to be subsequently used in the methane synthesis step and the hydrocarbon synthesis step, and this process is synthesized by a water gas conversion reaction. It is performed in the first water-gas shift step [S30, (b) step] of adjusting the ratio of carbon monoxide and hydrogen in the gas.

The water gas conversion reaction is converted to hydrogen and carbon dioxide by reacting with carbon monoxide and water of the synthesis gas as shown in the following reaction formula 2.

[Scheme 2]

CO + H ₂ O → CO ₂ + H ₂

By consuming some carbon monoxide of the synthesis gas through the water gas conversion reaction, the volume ratio of CO:H ₂ of the synthesis gas is 1: 1 to 3, preferably 1: 1.5 to 2.5, and more preferably 1: 2 I can adjust it.

When the amount of H ₂ contained in the synthesis gas obtained by the first water gas conversion step is less than the above range, there is a problem in that a large amount of hydrocarbons having a liquid C5 or higher under normal pressure is produced, and if it exceeds the above range, C1 There may be a problem that synthesis of lower hydrocarbons such as C4 is inhibited. In particular, the synthesis gas obtained by the first water gas conversion step as described above is directly supplied to the hydrocarbon synthesis step (S50) in which the volume ratio of H ₂ /CO should be adjusted to about 2, C1 of the hydrocarbon synthesis step (S50). It is advantageous for the production of lower C4 hydrocarbons.

The synthesis gas whose volume ratio of CO:H ₂ is adjusted by the first water gas conversion step is separated into two streams, and some of the separated streams are supplied to a hydrocarbon synthesis step [S50, (d) steps]. And some of the remaining synthesis gas is supplied to the second water gas conversion step [S35, (c) step] to control the H ₂ /CO so as to favor methanation synthesis, thereby performing the water gas conversion reaction.

The volume ratio of CO:H ₂ contained in the gas obtained by the second water gas conversion step may be 1:2 to 4, preferably 1:2.5 to 3.5, and more preferably 1:3. When the amount of H ₂ contained in the gas obtained by the second aqueous gas conversion step is less than the above range, the methane conversion rate of the methane synthesis step described later is low, and a problem of producing a large amount of C5 hydrocarbons or more in a liquid state at atmospheric pressure is produced. There is, there is a problem that the hydrocarbon synthesis of C2 to C4 is inhibited when it exceeds the above range.

The synthesis gas whose volume ratio of CO:H ₂ is controlled by the second water gas conversion step is subjected to a methane synthesis step [S40, (e) step] of methanation reaction. Same as 3.

[Scheme 3]

CO + 3H ₂ → CH ₄ + H ₂ O

As a result, the methane-containing gas obtained is composed of methane as its main component, and has similar components to natural gas, the main component of which is methane, but its calorific value is 9,500 Kcal/Nm ³ , which is the standard amount of liquefied natural gas supplied by the Korea Gas Corporation. Since it does not reach 10,400 Kcal/Nm ³ , in the present invention, a lower hydrocarbon compound having a high calorific value is synthesized using a part of the synthetic gas obtained in the water gas conversion step, and the lower hydrocarbon compound having a C4 or lower methane-containing gas To produce a synthetic natural gas having a calorific value of LNG. It will be described in detail below.

The present invention separates a part of the synthesis gas produced in the first water gas conversion step [(b) step, S30] as described above, and reacts a part of the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to C4 or less. To produce a lower hydrocarbon (step (d), S50).

In this case, the lower hydrocarbon of C4 or less is obtained as a methanol from the synthesis gas in one embodiment, and then a method for producing a hydrocarbon of C4 or less from the obtained methanol, and in another embodiment, the methanol synthesis catalyst and the hydrocarbon synthesis catalyst are physically It can be prepared by a single-step method for producing C4 or less hydrocarbons from the synthesis gas in the presence of a mixed catalyst.

More specifically, as an embodiment of the present invention, when producing a lower hydrocarbon of C4 or less via methanol from the synthesis gas, as shown in Figure 2, separating a portion of the synthesis gas obtained in the first water gas conversion step Then, methanol and/or dimethyl ether-containing gas are prepared by reacting a part of the separated synthesis gas in the presence of a methanol synthesis catalyst in the same manner as in Schemes 4 and 5 ((i) step, S51). At this time, the produced methanol may generate dimethyl ether by a dehydration dimerization reaction as shown in Scheme 6.

[Reaction Scheme 4]

CO + 2H ₂ → CH ₃ OH

[Scheme 5]

3CO + 3H ₂ → CH ₃ OCH ₃ + CO ₂

[Scheme 6]

CH ₃ OH → CH ₃ OCH ₃ + H ₂ O

The methanol and/or dimethyl ether-containing gas thus produced can produce lower hydrocarbons of C4 or lower by the reaction of Reaction Scheme 7 in the presence of a hydrocarbon synthesis catalyst together with the synthesis gas obtained in the first aqueous gas conversion step [(ii) Step S52]. At this time, in the hydrocarbon synthesis catalyst, carbene (H ₂ C:) is generated by dehydration of methanol and/or dimethyl ether-containing gas, and polymerization of the resulting carbene produces olefins whose main component is propylene or butane, The resulting olefin is hydrogenated with hydrogen in the synthesis gas to produce a hydrocarbon whose main component is propane or butane.

[Scheme 7]

In the reaction, water is generated, and the generated water may generate hydrogen by converting carbon monoxide and water gas of the synthesis gas, and the generated hydrogen can be used as a hydrogen source for the above-described hydrocarbon synthesis, making it more economical to lower hydrocarbons. Can be produced.

The reaction in step (i) can be appropriately determined reaction conditions such as reaction temperature and reaction pressure according to the type of the methanol synthesis catalyst, and preferably at a reaction temperature of 150°C to 500°C and a reaction pressure of 0.1 Mpa to 100 Mpa. It can be carried out, more preferably, the reaction temperature can be carried out at 200 ℃ ~ 400 ℃ and the reaction pressure 1 Mpa ~ 60 Mpa. In step (i), when the reaction temperature is 150°C or higher, or when the reaction pressure is 0.1 Mpa or higher, the conversion rate of carbon monoxide can be increased, and when the reaction temperature is 500 °C or lower or the reaction pressure is 100 Mpa or lower, side reaction is prevented. The yield of methanol and/or dimethyl ether can be improved.

The methanol synthesis catalyst may be used without limitation as long as it is a catalyst for producing methanol and/or dimethyl ether from synthesis gas, and for example, copper oxide-zinc oxide, copper oxide-zinc oxide-aluminum oxide (alumina), copper oxide-oxidation And Cu-Zn catalysts such as zinc-chromium oxide, Zn-Cr catalysts such as zinc oxide-chromium oxide, zinc oxide-chromium oxide-alumina, Cu-ZnO catalysts, and Pd catalysts. In addition, it may be an oxide containing Cu, Zn, Al, Ga, and M (at least one element selected from alkaline earth metals and rare earth elements). In addition, the methanol synthesis catalyst may contain other additive components as necessary within a range that does not impair its desired effect and purpose.

The synthesis of methanol and/or dimethyl ether in the step (i) may be performed by synthesizing methanol, dimethyl ether and mixtures thereof according to a known method, and may be performed by a gas phase reaction or a liquid phase reaction in which a methane synthesis catalyst is dispersed in an inert solvent. Can be. In the case of a liquid phase reaction, a petroleum-based solvent may be mentioned as a solvent, and the content of the methanol synthesis catalyst may be 25% by weight to 50% by weight.

On the other hand, the reaction in step (ii) can also appropriately determine reaction conditions such as reaction temperature and reaction pressure depending on the type of the hydrocarbon synthesis catalyst, and preferably at a reaction temperature of 150°C to 500°C and a reaction pressure of 0.1 Mpa to 100 Mpa. It can be carried out, more preferably at a reaction temperature of 300 °C to 500 °C and a reaction pressure of 0.1 Mpa to 10 Mpa. In the step (ii), when the reaction temperature is 150°C or higher, or when the reaction pressure is 0.1 Mpa or higher, higher selectivity of propane and butane can be obtained, and when the reaction temperature is 500 °C or lower or the reaction pressure is 100 Mpa or lower, the catalyst It is possible to increase the yield of the lower hydrocarbon compound by preventing side reactions while extending the life.

The hydrocarbon synthesis catalyst may be a catalyst carrying an olefin hydrogenation catalyst component on zeolite, and the olefin hydrogenation catalyst component means to exhibit a catalytic action on the hydrogenation reaction of olefin to paraffin, and the zeolite is a condensation reaction of methanol to hydrocarbon. And/or catalyzes the condensation reaction of dimethyl ether with hydrocarbons. In addition, the hydrocarbon synthesis catalyst may further include the methanol synthesis catalyst described above.

The olefin hydrogenation catalyst component may be used without limitation as long as it exhibits a catalytic action in the hydrogenation reaction of olefin to parffin, and for example, Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir, Pr, etc. It may be a kind or heterogeneous, and may be preferably Pd, Pt, and more preferably Pd in terms of more sufficiently suppressing byproducts of carbon monoxide and carbon dioxide while maintaining high propane and butane yields.

The content of the olefin hydrogenation catalyst component supported on the zeolite is 0.005% by weight or more, preferably 0.05% by weight to 5% by weight relative to the total weight of the catalyst, and the content of the olefin hydrogenation catalyst component in the above range is high conversion rate, high selectivity, Propane, butane, etc. can be produced with high yield.

The zeolite may be used without particular limitation as long as it is a zeolite showing a catalytic action in the condensation reaction of methanol and/or dimethyl ether with hydrocarbons. For example, one or more of ZSM-5, β-zeolite, USY zeolite, etc. may be used in combination. You may do it. In addition, ZSM-5, preferably ZSM-5 having a Si/Al ratio of 20 to 100, can be used in terms of more sufficiently suppressing byproducts of carbon monoxide and carbon dioxide while maintaining high propane and butane yields. .

The hydrocarbon synthesis catalyst may be prepared by a known method such as an ion exchange method or impregnation method, or a commercially available catalyst, and the hydrocarbon synthesis catalyst may contain components other than the olefin hydrogenation catalyst component within a range that does not impair its desired effect and purpose. It may be supported on zeolite.

In step (ii), methanol or dimethyl ether obtained in step (i) can be used alone as a reaction raw material, and a mixture of methanol and dimethyl ether can also be used. When a mixture of methanol and dimethyl ether is used as the reaction raw material, the content ratio of methanol and dimethyl ether is not particularly limited and can be appropriately determined.

In addition, in the step (ii), the by-product water is further separated (S60), and other components are separated as necessary to prepare a lower hydrocarbon containing propane or butane as a main component. The water separation may be performed by a known method such as liquid-liquid separation, cooling gas-liquid separation, and the separated water may be supplied to the first water gas conversion step and the second water gas conversion step and recycled in the water gas conversion reaction. .

Preparation of lower hydrocarbons of C4 or less via methanol from the above-described syngas was described in two steps for detailed description, but the technical feature of the present invention is C4 or less in the presence of methanol synthesis catalyst and hydrocarbon synthesis catalyst using synthesis gas. Since a low-grade hydrocarbon is produced and mixed with methane-containing gas prepared in the methane synthesis step to produce a synthetic natural gas with an increased calorific value, various modifications and variations are possible without departing from the technical spirit of the present invention. .

For example, the reaction may be performed by laminating the methanol synthesis catalyst and the hydrocarbon synthesis catalyst in one reactor, or the reaction may be performed within a single process by separating the methanol synthesis catalyst and the hydrocarbon synthesis catalyst at regular intervals in one reactor. have.

On the other hand, in another embodiment of the present invention, C1 to C4 lower hydrocarbons may be prepared by a reaction as shown in Reaction Scheme 8 in a mixed catalyst in which a methanol synthesis catalyst and a hydrocarbon synthesis catalyst are physically mixed as shown in FIG. 1.

[Scheme 8]

The mixed catalyst is a catalyst in which the above-described methanol synthesis catalyst and a hydrocarbon synthesis catalyst are physically mixed, and when a part of the synthesis gas obtained in the first water gas conversion step [S30, (b) step] is brought into contact with the mixed catalyst, methanol is synthesized. In the catalyst, methanol is synthesized from carbon monoxide and hydrogen. At this time, dimethyl ether is also produced by dehydration dimerization of the methanol. Subsequently, the synthesized methanol is converted into a lower olefin hydrocarbon whose main component is propylene or butene at the active point in the pores of the hydrocarbon synthesis catalyst in the same process as the co-reaction process conducted in the above two steps, and the converted lower olefin is the main component by hydrogenation. It is made of lower hydrocarbons, propane or butane.

The reaction may also appropriately determine reaction conditions, such as reaction temperature and reaction pressure, depending on the type of the mixed catalyst, and preferably, can be performed at a reaction temperature of 150°C to 500°C and a reaction pressure of 0.1Mpa to 100Mpa, more preferably It can be carried out at a reaction temperature of 200 ℃ ~ 400 ℃ and a reaction pressure of 0.1Mpa ~ 10 Mpa. When the reaction temperature is 150°C or higher, or when the reaction pressure is 0.1 Mpa or higher, higher selectivity of propane and butane can be obtained. When the reaction temperature is 500 °C or lower, or when the reaction pressure is 100 Mpa or lower, the side reaction is extended while extending the catalyst life. It can prevent and increase the yield of a lower hydrocarbon compound.

In the mixed catalyst of the present invention, the ratio of the methanol synthesis catalyst and the hydrocarbon synthesis catalyst is not particularly limited, but preferably, the weight ratio of the methanol synthesis catalyst and the hydrocarbon synthesis catalyst is 4:1 to 1:4, more preferably 2:1. ~ 1: May be 2.

The mixed catalyst is preferably prepared separately from a methanol synthesis catalyst and a hydrocarbon synthesis catalyst, and mixed. By separately preparing a methanol synthesis catalyst and a hydrocarbon synthesis catalyst, it is possible to easily design each composition, structure, physical properties, etc. optimally for each function.

The methanol synthesis catalyst and the hydrocarbon synthesis catalyst have an average particle diameter of 100 μm or more, preferably 200 μm to 5 mm, which may have the same particle size or different particles, but have the same particle size in terms of uniform mixing. desirable. Catalysts having an average particle diameter in the above range can obtain a catalyst having a long life and little deterioration.

In addition, the methanol synthesis catalyst and the hydrocarbon synthesis catalyst can be used separately after being separately molded, and the mixture obtained by the above mixing can also be used by molding.

The lower hydrocarbons of C1 to C4 synthesized as described above may be mixed with the methane syngas obtained in the methane synthesis step [(e) step, S40] to finally produce a synthetic natural gas with increased calorific value [(f ) Step, S70]. At this time, the calorific value of the finally obtained synthetic natural gas is preferably 10,400 kcal/Nm ³ or more.

On the other hand, the amount of gas input to the hydrocarbon synthesis step of the gas obtained by the water gas conversion step is preferably adjusted according to the calorific value of the synthetic natural gas finally obtained.

More specifically, the calorific value of the synthetic natural gas finally obtained is 10,400 kcal/Nm ³ If less than, it is preferable to increase the amount of gas inputted into the hydrocarbon synthesis step among the gases obtained by the water gas conversion step, and the calorific value of the finally obtained synthetic natural gas (SNG) is 10,400 kcal/Nm ³ or more It is preferable to reduce the amount of gas input to the hydrocarbon synthesis step among the gases obtained by the water gas conversion step.

According to the present invention, a method for manufacturing a synthetic natural gas having an increased calorific value is obtained from a solid carbon such as coal, biomass, petroleum coke, and the like. It can be provided without replenishment of hydrocarbons, and by increasing the selectivity of lower hydrocarbons of C4 or lower for adjusting the calorific value of synthetic natural gas in the production process of synthetic natural gas, additional separation purification and upgrading process for hydrocarbons of C5 or higher can be provided. It has the effect of minimizing the production of high-heat synthetic natural gas.

In another aspect, the present invention is a gasification unit for gasifying fuel to obtain a synthesis gas; A first aqueous gas conversion unit for converting the obtained synthesis gas into an aqueous gas conversion reaction; A second water gas conversion unit that converts the first water gas converted synthesis gas into a water gas conversion reaction; A hydrocarbon synthesis unit for separating a part of the first water gas converted synthesis gas and reacting the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons; A methane synthesis unit for producing a methane-containing gas by methanation reaction of the second water gas converted synthesis gas; And a mixing unit for producing a synthetic natural gas by mixing C1 to C4 lower hydrocarbons produced in a hydrocarbon synthesizing unit with the methane-containing gas.

The reaction occurring in each unit of the system for producing synthetic natural gas with increased calorific value according to the present invention is the same as mentioned in the method for producing synthetic natural gas with increased calorific value, so that those skilled in the art can clearly understand the manufacturing system. As will be understood, the following description will be omitted to avoid duplication.

Although the present invention has been described in detail above, the scope of the present invention is not limited thereto, and it is common in the art that various modifications and variations are possible without departing from the technical spirit of the present invention as set forth in the claims. It will be obvious to those who have the knowledge of

Claims (13)

(a) gasifying the fuel to obtain a syngas;
(b) a first aqueous gas conversion step of converting the obtained synthesis gas into an aqueous gas conversion reaction;
(c) a second water gas conversion step of separating a part of the synthesis gas obtained in the first water gas conversion step to perform a water gas conversion reaction;
(d) a hydrocarbon synthesis step of separating a part of the synthesis gas obtained in the first water gas conversion step, and reacting a part of the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons;
(e) a methane synthesis step of producing a methane-containing gas by methane synthesis reaction of the synthesis gas obtained in the second water gas conversion step; And
(f) mixing the C1 to C4 lower hydrocarbons produced in the hydrocarbon synthesis step with the methane-containing gas produced in the methane synthesis step to produce a synthetic natural gas; a method for producing a synthetic natural gas with an increased calorific value. According to claim 1,
The fuel is a method for producing a synthetic natural gas with an increased calorific value, characterized in that at least one selected from the group consisting of coal, biomass and solid carbon. According to claim 1,
The method for producing a synthetic natural gas with an increased calorific value, characterized in that the volume ratio of CO:H ₂ contained in the synthetic gas obtained in the step (b) is 1:1 to 3. According to claim 1,
The method of manufacturing a synthetic natural gas with an increased calorific value, characterized in that the volume ratio of CO:H ₂ contained in the synthetic gas obtained in the step (c) is 1:2 to 4. According to claim 1,
In step (d), (i) a part of the synthesis gas obtained in the first water gas conversion step is separated, and a part of the separated synthesis gas is reacted in the presence of a methanol synthesis catalyst to produce methanol and/or dimethyl ether-containing gas. step; And (ii) producing C1 to C4 lower hydrocarbons by reacting the prepared methanol and/or dimethyl ether-containing gas and a part of the synthesis gas obtained in the first aqueous gas conversion step in the presence of a hydrocarbon synthesis catalyst. Method for producing synthetic natural gas with increased calorific value. According to claim 1,
In the step (d), a part of the synthesis gas obtained in the first water gas conversion step is separated, and a part of the separated synthesis gas is reacted in the presence of a mixed catalyst in which a methanol synthesis catalyst and a hydrocarbon synthesis catalyst are mixed to form C1 to C4 lower hydrocarbons. Method for producing a synthetic natural gas is increased heat generation, characterized in that to manufacture. The method of claim 5 or 6,
The methanol synthesis catalyst is a Cu-Zn-based catalyst, Pd-Zn-Cr-based catalyst, Zn-Cr-based catalyst and the production of synthetic natural gas with increased calorific value, characterized in that at least one member selected from the group consisting of Pd-based catalyst Way. The method of claim 5 or 6,
The hydrocarbon synthesis catalyst is Fe, Co, Ni, Cu, Zn, Ru, Rh, Pd, Ir and Pr is a synthetic natural gas with increased calorific value, characterized in that it is a zeolite-based catalyst supported by at least one member selected from the group consisting of Gas production method. The method of claim 6,
The mixed catalyst is a method for producing a synthetic natural gas with an increased calorific value, characterized in that the methanol synthesis catalyst and the hydrocarbon synthesis catalyst are mixed in a weight ratio of 4:1 to 1:4. A gasification unit for gasifying fuel to obtain a synthesis gas;
A first aqueous gas conversion unit for converting the obtained synthesis gas into an aqueous gas conversion reaction;
A second water gas conversion unit that separates a portion of the synthesis gas converted from water gas from the first water gas conversion unit to perform water gas conversion reaction;
A hydrocarbon synthesis unit for separating a part of the synthesis gas converted into water gas from the first water gas conversion unit and reacting the separated synthesis gas in the presence of a methanol synthesis catalyst and a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons;
A methane synthesis unit for producing a methane-containing gas by methanation reaction of the synthesis gas converted from the water gas in the second water gas conversion unit; And
Mixing unit for producing a synthetic natural gas by mixing the C1 to C4 lower hydrocarbons produced by the hydrocarbon synthesis unit to the methane-containing gas; Synthetic natural gas production system comprising an increased heat generation. The method of claim 10,
The fuel is a system for producing synthetic natural gas with increased calorific value, characterized in that at least one selected from the group consisting of coal, biomass and solid carbon. The method of claim 10,
The hydrocarbon synthesis unit comprises a methanol synthesis unit for separating a portion of the first water gas converted synthesis gas and reacting the separated synthesis gas in the presence of a methanol synthesis catalyst to produce methanol and/or dimethyl ether-containing gas; And a hydrocarbon synthesis unit that reacts a portion of the prepared methanol and/or dimethyl ether-containing gas and the first aqueous gas-converted synthesis gas in the presence of a hydrocarbon synthesis catalyst to produce C1 to C4 lower hydrocarbons. Increased synthetic natural gas production system. The method of claim 10,
The hydrocarbon synthesizing unit is characterized by producing a C1 to C4 lower hydrocarbon by separating a part of the first gas converted gas conversion and reacting a part of the separated syngas in the presence of a mixed catalyst in which methanol synthesis catalyst and hydrocarbon synthesis catalyst are mixed. Synthetic natural gas production system with increased calorific value.

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