KR20210095758A - Membrane Module with Tubular Hydrogen Separator designed to increase hydrogen recovery and Device and Process for hydrogen production using the same - Google Patents

Abstract

The present invention is a membrane module having a tubular hydrogen separator designed to increase the hydrogen recovery rate, a hydrogen purification process using the membrane module; and a hydrogen production apparatus and process using the membrane module as a fossil fuel-based membrane reactor. Based on the gas flow direction connected from a feed port to an outlet, a space is divided into a first room, a second room, ..., and a n^th room (n >= 2), and in each room, a first side hydrogen pressure (P_outside) > a second side hydrogen pressure (P_inside) based on a tubular hydrogen separator which lets hydrogen pass from a first side, an outside, to a second side, an inside. A tubular hydrogen separator discharging hydrogen which has passed through the hydrogen separator is installed in plural. The present invention relates to a design of a shell-and-tube type membrane module having a tubular hydrogen separator for the purpose of increasing the hydrogen recovery rate.

Description

Membrane Module with Tubular Hydrogen Separator designed to increase hydrogen recovery and Device and Process for hydrogen production using the same}

The present invention is a separation membrane module having a tubular hydrogen separation membrane designed to increase the hydrogen recovery rate; Hydrogen purification process using the separation membrane module; And it relates to a hydrogen production apparatus and process using the membrane module as a fossil fuel-based membrane reactor.

Hydrogen has received much attention as a clean energy carrier and is one of the most promising alternative energy sources in the world due to its economical, environmentally friendly and renewable use. Currently, large amounts of hydrogen are being produced from fossil fuel-based methods such as natural gas steam reforming, coal gasification, water electrolysis, biomass gasification and other thermochemical processes. Of these, the most widely used technology is natural gas steam reforming. Steam methane reforming (SMR) is particularly economical and is commonly used to produce hydrogen from natural gas as it is the source of methane with the highest hydrogen yield.

However, hydrogen is not the only product of natural gas reforming, which requires a purification step to extract high purity hydrogen from the gas mixture.

Currently commercialized purification processes include adsorption, membrane separation, and deep cooling. Pressure Swing Adsorption (PSA), Thermal Swing Adsorption (TSA), Cryogenic Distillation, and Getter are currently commercially available processes, but they have low energy efficiency and require complex configurations.

On the other hand, natural gas, coal, and biomass produce syngas through a reforming reaction, and the produced syngas is used for chemical synthesis raw materials, fuels and industrial processes through various downstream processes. In addition, the produced syngas contains a large amount of hydrogen. This hydrogen is used in ammonia synthesis, oil refining process, smelting process, polysilicon manufacturing process, semiconductor manufacturing process, and LED manufacturing process through refining process. It is an essential substance. In particular, when hydrogen is linked with a fuel cell, its value is increasing day by day as a clean energy source with high efficiency and no emission of pollutants.

^{On the other hand, 50 ~ 5,000 Nm 3} to supply hydrogen locally by breaking away from the existing transport method to various industrial facilities such as ammonia synthesis, oil refining process, semiconductor manufacturing process, LED manufacturing process, polysilicon manufacturing process, and steel industry. The development of a /h-class small and medium-sized hydrogen production plant is in progress.

Steam Methane Reforming (SMR) of methane is a reaction in which methane gas is reformed in the presence of steam using a catalyst and chemically converted into _{synthesis gas (a mixed gas of CO + H 2 ) as shown in Reaction Equation 1 below.}

[Scheme 1]

CH ₄ + H ₂ O → CO + 3H ₂ ΔH = 206.28 kJ/mol

SMR has the advantage of having a CO ₂ /H _{2 ratio of 0.25 in the product gas, a lower CO 2} production ratio compared to a partial oxidation process using hydrocarbons as a raw material, and that a greater amount of hydrogen can be obtained from a certain amount of hydrocarbons.

_{Since the ratio of CO/H 2 is} high in the fluid produced in the SMR process, _{CO can be converted into CO 2} and H ₂ through a conversion reaction as shown in Scheme 2 below. This is called a water-gas shift reaction (WGS).

[Scheme 2]

CO + H ₂ O → CO ₂ + H ₂ ΔH = -41.3 kJ/mol

The conversion reaction includes a high-temperature conversion reaction and a low-temperature conversion reaction depending on the temperature.

Accordingly, after the SMR process, a high temperature shift reaction (HTS) process and a low temperature shift reaction (LTS) process may be connected. High-temperature conversion reaction can be carried out at 350 ~ 550 ℃ using _{a Fe 2} O _{3 catalyst to which Cr 2} O ₃ is added as a co-catalyst. Chemical components of a typical used catalyst are Fe (56.5-57.5%) and Cr (5.6-6.0%). The low-temperature conversion reaction is carried out at 200 to 250° C., and a catalyst such as CuO (15 to 31%)/ZnO (36 to 62%)/Al ₂ O ₃ (0 to 40%) is used. Recently, Cr-based low-temperature conversion catalysts have been developed. The minimum reaction temperature must be higher than the dew point of the water gas, and the CO concentration in the exhaust gas is 1% or less. The low-temperature conversion catalyst is initially used after being converted to a reduced state through an activation process.

On the other hand, hydrogen fuel cells have relatively high energy efficiency compared to other renewable energies such as solar power, solar heat, and wind power. In addition, wind power or solar power has a lot of ups and downs in output depending on climatic conditions, but in the case of a hydrogen fuel cell, the desired output capacity can be designed in advance according to the use, so hydrogen is the most stable energy resource and is the best renewable energy it can be said

In addition, it is expected that the demand for eco-friendly vehicles, including hydrogen fuel cell vehicles, will increase as environmental regulations for automobiles are strengthened around the world, and the construction of hydrogen charging stations is expected to increase accordingly. There are two types of hydrogen refueling stations: an off-site method that transports and stores by-product hydrogen generated from a petrochemical complex under high pressure, and an on-site method that manufactures and supplies hydrogen at the charging station site. Hydrogen production facilities of on-site hydrogen refueling stations mainly use natural gas reforming.

In conventional SMR, natural gas and steam react with a reforming catalyst under conditions of high temperature (> 1123 K) and pressure (> 3.5 MPa) to produce synthesis gas containing hydrogen, carbon dioxide, carbon monoxide and methane. Hydrogen production by SMR generally proceeds through three main units: a steam reforming reactor, two hot and cold water gas shift (WGS) reactors, and a gas purification system. The reforming step is followed by a Pressure Swing Adsorption (PSA) based purification to obtain high purity hydrogen from the reformed stream.

On the other hand, the hydrogen separation membrane plays an important role in hydrogen production and purification. Among the various hydrogen permeable membranes, Pd-based membranes are excellent for use in commercial applications such as hydrocarbon steam reforming, fuel cells and hydrogen-based reactions because of their excellent hydrogen selectivity. In addition, Pd-based membranes can overcome the thermodynamic equilibrium limit predicted by Le Chatelier's principle to improve the product yield of the reaction and enhance conversion. Thus, by using a Pd-based membrane, the SMR and WGS units can be integrated and the downstream hydrogen purification unit can be eliminated, thereby improving conversion efficiency while reducing overall reactor volume and process cost.

Depending on the membrane configuration, Pd-based membranes can be structurally classified into self-supported and composite membranes. Pd and Pd alloy foils have been commercialized, supplying high purity hydrogen (> 99.999 %) to the semiconductor and electronics industries. However, in order to produce ultra-high purity hydrogen on an industrial scale, the film thickness must be greater than 15 μm to maintain structural integrity. This increases the material cost and reduces the hydrogen permeation flux. Compared with foil-type membranes, composite membranes have attracted great attention due to their low cost, good hydrogen permeation flux and high mechanical strength. Several studies have reported the preparation of Pd composite membranes using a porous support, which helps to reduce the membrane thickness while maintaining mechanical strength. Recently, research has been conducted to meet the needs for long-term thermal stability and module design.

The present invention intends to design a shell-and-tube type membrane module having a tubular hydrogen separation membrane for the purpose of increasing the hydrogen recovery rate.

A first aspect of the present invention is a separation membrane module having a tubular hydrogen separation membrane designed to increase the hydrogen recovery rate, and based on the gas flow direction connected from the module inlet (feed port) to the outlet, the first space (1 ^st) room), the second space (2 ^nd room), … , divided by n ^th room (n ≥ 2), and in each space, based on a tubular hydrogen separation membrane that passes hydrogen from the first side that is outside to the second side that is inside Hydrogen partial pressure on the first side (P _outside ) > hydrogen partial pressure on the second side (P _inside ), characterized in that one or more tubular hydrogen separation membranes are disposed to discharge hydrogen that has passed through the hydrogen separation membrane through the open part on the second side A separator module is provided.

A second aspect of the present invention is a separation membrane reactor in which a catalyst is mounted inside the separation membrane module of the first aspect and capable of a chemical reaction. The separation membrane reactor having a hydrogen separation membrane module designed to increase hydrogen recovery rate is a shell space separated by a partition wall Hydrogen generation reaction by the internally packed catalyst and its product hydrogen are separated from hydrogen through a Pd-based membrane at the same time, and a catalyst mounted in a shell space separated by a barrier (i) reforming catalyst, (ii) reforming catalyst and catalyst for water-gas shift reaction (WGS), (iii) reforming catalyst and CO ₂ adsorbent, (iv) reforming catalyst and water-gas shift reaction catalyst and CO ₂ adsorbent, (v) water gas conversion Catalyst for reaction, (vi) provides a membrane reactor characterized by using a catalyst for water gas conversion reaction and a CO _{2 adsorbent}

A third aspect of the present invention provides a method for producing hydrogen in the separation membrane module of the first aspect.

A fourth aspect of the present invention is a method for producing concentrated hydrogen from a methane-containing gas in the separation membrane reactor of the second aspect, comprising: a first step of performing a methane reforming reaction in at least one space partitioned by a partition; and a second step of separating hydrogen synthesized in the methane reforming reaction through a tubular hydrogen separation membrane disposed in a space where the methane reforming reaction is performed, wherein the methane reforming reaction occurs on the first side of the hydrogen separation membrane Provided is a hydrogen production method characterized in that the hydrogen generated on the second side is passed through the methane reforming reaction that occurs on the first side, and hydrogen, which is a product, is removed and the hydrogen is concentrated on the second side.

A fifth aspect of the present invention is the separation membrane module of the first aspect; and a fuel cell using the hydrogen enriched gas provided from the separation membrane module as a fuel.

Hereinafter, the present invention will be described.

The membrane stage cut, defined as the fraction of feed gas that permeates the membrane, is a measure of the degree of separation required. A typical goal of gas separation systems is to produce a residue stream substantially free of permeable components and a concentrated permeate stream.

The present invention is provided with a tubular hydrogen separation membrane to increase the hydrogen recovery rate in the combined shell-and-tube type module when hydrogen separation proceeds,

^{2 to 4, the first space (1 st} room), the second space (2 ^nd room) through the partition wall (blue) based on the gas flow direction connected from the module inlet (feed port) to the outlet (2 nd room) ), … , ^{divide the n th} room (n ≥ 2),

In each space, hydrogen partial pressure at the first side (P _outside ) > hydrogen partial pressure at the second side ( P _inside ) and the separation membrane module is designed so that one or more tubular hydrogen separation membranes are arranged to discharge hydrogen that has passed through the hydrogen separation membrane through the open part on the second side.

Another feature of the present invention is that these features are implemented in one module as shown in FIGS. 2 to 4 .

From an economical point of view, n is preferably 7 or less, and more preferably 4 or less.

In order for hydrogen to permeate through the membrane, there must be a difference in hydrogen partial pressure with respect to the membrane. That is, in order to pass hydrogen from the first side, which is outside, to the second side, which is inside, in the tubular hydrogen separation membrane, partial pressure of hydrogen at the first side (P _outside ) > partial pressure of hydrogen at the second side (P _inside) ) should be

where, P _i : hydrogen partial pressure,

P _inside : the internal hydrogen partial pressure of the tubular hydrogen separation membrane,

P _outside : External hydrogen partial pressure of the tubular hydrogen separation membrane.

As hydrogen passes from the outside to the inside of the tubular hydrogen separation membrane, the partial pressure difference _{between the hydrogen partial pressure on the supply side (P outside} ) and the hydrogen partial pressure on the permeation side (P _{inside ) becomes smaller as it goes downstream in the longitudinal direction of the tubular hydrogen separation membrane.} The hydrogen recovery amount may decrease and eventually become zero.

As shown in Figure 1, in a shell-and-tube type separation membrane module having a single-stage tubular hydrogen separation membrane module, a hydrogen separation reaction occurs in Zone 1 where the hydrogen _{partial pressure relationship in the first-stage module is P 1} > P _{2, but P After Zone 2 where 2} ≒ P ₃ , there is no difference in hydrogen partial pressure, so it cannot function as a separator.

Therefore, the present invention is to increase the hydrogen recovery rate in a shell-and-tube type separation membrane module having a tubular hydrogen separation membrane, that is, hydrogen partial pressure so that hydrogen can be recovered through hydrogen permeation even in Zone 2 of the single-stage tubular hydrogen separation membrane module To give a difference, a two-stage tubular hydrogen separation membrane module that divides the tubular hydrogen separation membrane into Zone 1 and Zone 2 and separately configures the tubular hydrogen separation membrane in each zone, but arranges not to be connected in series on the side of the hydrogen flow passing through the hydrogen separation membrane It is characterized by its design.

As illustrated in Figure 1, in the two-stage tubular hydrogen separation membrane module, in the first-stage tubular hydrogen separation membrane module, the hydrogen partial pressure relationship is P ₁ > P ₂ in the downstream of Zone 1, P ₂ ≒ P ₃ In the second-stage tubular hydrogen separation membrane module designed to have a partial pressure difference that allows hydrogen to pass through, the residual hydrogen after separation proceeds _{when P 5} ≒ P ₆ in Zone 2 where the _{hydrogen partial pressure relationship is P 4} > P ₅ By adding the hydrogen recovery rate that can be implemented in the second-stage tubular hydrogen separation membrane module to the hydrogen recovery rate that can be implemented in the first-stage tubular hydrogen separation membrane module, the overall hydrogen recovery rate of the separation membrane module can be increased.

That is, the present invention provides a first space (1 ^st room), a second space (2 ^nd room), . , ^{divide the n th} room (n ≥ 2),

In each space, hydrogen partial pressure at the first side (P _outside ) > hydrogen partial pressure at the second side ( P _inside ) and by disposing one or more tubular hydrogen separation membranes that discharge hydrogen that has passed through the hydrogen separation membrane through the open part on the second side,

The length of the first tubular hydrogen separation membrane disposed in the first space (1 ^st room), the length of the second tubular hydrogen separation membrane disposed in the second ^{space (2 nd room), ...} , and than the hydrogen recovery rate in the tubular hydrogen separation membrane having a length corresponding to the sum of the lengths of the nth tubular hydrogen separation membrane disposed in the ^{n th room,}

Hydrogen recovery amount in the first tubular hydrogen separation membrane, hydrogen recovery amount in the second tubular hydrogen separation membrane, … , and the sum of the hydrogen recovery amount in the n-th tubular hydrogen separation membrane can be made larger.

In addition, the total amount of hydrogen recovery in the separation membrane module having a tubular hydrogen separation membrane according to the present invention is the amount of hydrogen recovery in the first stage module composed of the first tubular hydrogen separation membranes disposed in the first space, in the second space Hydrogen recovery amount in the second stage module composed of the arranged second tubular hydrogen separation membranes, ... , and the sum of the amount of hydrogen recovery in the n-th module composed of the n-th tubular hydrogen separation membranes disposed in the n-th space.

Therefore, as the hydrogen partial pressure difference is reduced according to the length of the tubular hydrogen separation membrane, the hydrogen recovery rate can be increased in one separation membrane module having compact tubular hydrogen separation membranes by overcoming the disadvantage of not exhibiting the maximum separation membrane performance.

The tubular hydrogen separation membrane is advantageous for large-capacity hydrogen production as it is easy to enlarge the area in the length and diameter directions when the reactor is installed. In addition, the hydrogen-enriched gas may be collected in the inner space or pores of the tubular hydrogen separation membrane structure.

In the present invention, the gas continuously flowing through each space separated through the partition wall from the separation membrane module inlet and discharged out of the separation membrane module is a retentate gas from which hydrogen has been removed through the hydrogen separation membrane, and the residual gas from which hydrogen has been removed through the hydrogen separation membrane ( The retentate) may be designed so that the outlet (retentate port) from which the gas flow is discharged and the outlet (permeation port) through which the hydrogen collected in the inner space of the tubular hydrogen separation membrane through the hydrogen separation membrane is discharged (permeation port).

For example, in the separation membrane module of the present invention, the residual hydrogen remaining after the primary hydrogen separation in the first space is separated in the second space, and the hydrogen separated through the hydrogen separation membrane in the first space and the second space is collected in the separation membrane module ( The residual gas collected by the collector and unseparated may be discharged through a residual gas outlet (retentate port).

In the separation membrane module of the present invention, it is preferable to generate helical fluidization in the gas flow supplied to the first space through the module feed port, thereby forming turbulence around the tubular hydrogen separation membrane, but it is not necessary to limit the flow thereto. However, turbulent gas flow can be generated around the tubular hydrogen separation membrane through spiral fluidization, resulting in excellent mass transfer.

In addition, in order to generate a descending spiral fluidization in the gas flow supplied to the first space through the module inlet (feed port), the module inlet is disposed on the upper side or upper side of the separation membrane module, and the first space through the descending spiral fluidization After flowing, it can flow in a countercurrent upward direction into the second space.

As illustrated in FIG. 4 , in order to generate efficiently descending spiral fluidization, the upper portion of the first space starting at the top of the reactor where the module feed port is disposed may be in the form of a cone or a truncated truncated cone.

In the separation membrane module of the present invention, a vortex flow is given to the fluid supplied through the module inlet by borrowing a part of the driving principle of the cyclone and introduced into the first space, and the vortex flow effect in the first space The circulating flow in the first space can be driven so that the hydrogen separation reaction occurs while winding the tubular hydrogen separation membrane.

The separation membrane module of the present invention may be a shell-and-tube type module having tubular hydrogen separation membranes. Furthermore, one or more partition walls may be disposed on a concentric circle inside the shell-and-tube type module, and a tubular hydrogen separation membrane may be installed in a space separated through the partition wall.

Hydrogen separation membrane is a metal dense membrane, where hydrogen molecules adsorb to the metal surface and dissociate into hydrogen atoms, the hydrogen atoms move between the metal lattice, recombine into hydrogen molecules on the other side of the separation membrane, and hydrogen permeates through the process of desorption from the metal surface. there is.

A typical example of a hydrogen separation membrane is a palladium-based metal dense separation membrane.

When the hydrogen separation membrane is a composite membrane composed of a porous support and a membrane layer, the thickness of the membrane, which is a limitation of the foil-type self-supported membrane, can be lowered, the hydrogen permeability can be significantly increased, and modularization for systemization is easy. In general, the hydrogen separation membrane may be implemented as a tubular separation membrane depending on the shape of the support.

For example, the hydrogen separation membrane may include a palladium-based dense layer; optionally a diffusion barrier layer; and a porous support may be laminated.

At this time, the hydrogen separation membrane of the present invention may have a porous support on the first surface, a palladium-based dense membrane layer on the second surface, or a porous support on the second surface, and a palladium-based dense membrane layer on the first surface. there is.

The palladium-based dense film may be palladium or a palladium alloy. The palladium alloy may be an alloy of Pd and at least one metal selected from the group consisting of Au, Ag, Cu, Ni, Ru and Rh. The palladium-based dense film may further include layers such as Pd/Cu, Pd/Au, Pd/Ag, and Pd/Pt in a multi-layered structure. The palladium-based dense film may be formed to a thickness of 0.1 to 20 μm, preferably 1 to 10 μm. If the thickness is less than 0.1 μm, it is good because the hydrogen permeability is further improved. When the thickness is more than 20 μm, it can be formed densely, while the hydrogen permeability is relatively low, so there is a problem in that the number of separation membranes increases. Among the palladium-based dense film coating methods, the electroless plating method is a technology that enables large-area coating regardless of the shape of the support.

Typically, as a hydrogen separation membrane of a palladium-based dense membrane, the operating temperature is 300 ~ 600 ℃.

In the palladium-based dense membrane, the hydrogen permeation rate is mainly determined by the hydrogen partial pressure P1 on the supply side, the hydrogen partial pressure P2 on the refining side, the film thickness t of the palladium-based dense membrane, and the membrane area of the palladium-based dense membrane. That is, the hydrogen permeation amount Q per unit area is in the relationship of the following formula (1).

In the above formula, A varies depending on the type of alloy film or operating conditions.

For a hydrogen permeable membrane based on a palladium alloy, a method of improving the hydrogen permeability by reducing the film thickness is mainly considered. Since the amount of hydrogen permeation is affected by the difference in partial pressure of hydrogen, both thinning and strength are required. Therefore, a palladium alloy with a thin film thickness is used in combination with the porous support as described above to supplement the mechanical strength. The size of the pores on the surface of the porous support is preferably formed to have a range of 0.001 to 10 ㎛.

For example, a palladium-based dense membrane may be disposed on the outside of the tubular or cylindrical porous nickel support, and the hydrogen enriched gas may be collected in the internal space or pores of the tubular or cylindrical porous nickel support.

On the other hand, when the porous support is a metal when manufacturing a hydrogen separation composite membrane, when a palladium-based dense membrane is formed directly on a porous metal support, diffusion problems occur between Pd, which is a component of the palladium-based dense membrane, and the metal support, so a diffusion barrier layer between them (diffusion barrier) is required. The diffusion barrier formed on the porous metal support, that is, the porous shielding layer, is to prevent diffusion that may occur between palladium, a component of the palladium-based dense membrane, and the metal support, hydrogen can pass through the pores/gap. As there is, it may be formed of a ceramic material. Non-limiting examples of the shielding layer include oxide-based, nitride-based, and carbide-based ceramics including one of Ti, Zr, Al, Si, Ce, La, Sr, Cr, V, Nb, Ga, Ta, W, and Mo. there is. Preferably, there is _{an oxide-based ceramic material such as TiO y} , ZrO _y , Al ₂ O _z (1<y≤2 or 2<z≤3).

As illustrated in FIG. 11 , two or more separation membrane modules having a tubular hydrogen separation membrane designed to increase the hydrogen recovery rate according to the present invention may be connected in series, in which case hydrogen is removed from the upstream separation membrane module. The outlet (retentate port) of may be connected to the inlet (feed port) of the downstream (downstream) membrane module.

As shown in FIG. 11, the present invention can improve the hydrogen recovery rate by connecting the retentate port of the first separator module and the feed port of the second separator module during multi-stage serial connection.

This is different from the existing separation cascade method in which the permeation port and the feed port are connected to increase the hydrogen purity as shown in FIG. 12 . The existing permeation port-feed port connection method operates by determining the stage-cut in each module to match the final product concentration in each reactor module. Therefore, the recovery rate is determined in each reactor module, and the final recovery rate decreases as the number of series-connected modules increases.

A membrane module having a tubular hydrogen separation membrane according to the present invention may be used in a method of producing and/or purifying hydrogen.

At this time, a reactant or hydrogen-containing mixed gas required for hydrogen production may be supplied through the membrane module inlet (feed port).

Non-limiting examples of reactants required for hydrogen production, supplied through a module inlet (feed port), include a mixed gas such as natural gas and steam, and non-limiting examples of a hydrogen-containing mixed gas supplied through a module inlet (feed port) A typical example is _{a mixed gas of H 2} + CO ₂ , CH _4, CO, steam, O ₂ and the like.

In addition, when oxygen is included in the gas supplied through the inlet of the membrane module, an inert gas such as nitrogen may be additionally supplied to the reactor to prevent explosion due to hydrogen combustion.

Furthermore, the separation membrane module having a tubular hydrogen separation membrane according to the present invention can be used as a separation membrane reactor in which a catalyst is mounted inside the separation membrane module and a chemical reaction is possible.

According to the present invention, a separation membrane reactor having a hydrogen separation membrane module designed to increase the hydrogen recovery rate is a hydrogen production reaction by a catalyst filled in a shell space separated by a partition wall, and hydrogen as a product thereof is hydrogen separation through a Pd-based membrane may be occurring simultaneously.

At this time, as illustrated in FIGS. 5 to 10, (i) reforming catalyst (FIG. 5), (ii) reforming catalyst and water gas shift reaction (water-gas shift) as a catalyst filled in a shell space separated by a partition wall reaction, WGS) catalyst (FIG. 6), (iii) reforming catalyst and CO ₂ adsorbent (FIG. 7), (iv) reforming catalyst and water gas shift catalyst and CO ₂ adsorbent (FIG. 8), (v) aqueous Catalyst for gas shift reaction (FIG. 9), (vi) a catalyst for water gas shift reaction and CO ₂ adsorbent (FIG. 10) may be used.

Carbon dioxide formed by the methane reforming reaction on the first side of the hydrogen separation membrane may be captured by a solid carbon dioxide absorbent.

For example, in a membrane reactor equipped with a tubular hydrogen separation membrane module according to the present invention, a method of producing concentrated hydrogen from a methane-containing gas,

A first step of performing a methane reforming reaction in at least one space partitioned by a partition; and

and a second step of separating hydrogen synthesized in the methane reforming reaction through a tubular hydrogen separation membrane disposed in a space in which the methane reforming reaction is performed.

At this time, the methane reforming reaction takes place on the first side of the hydrogen separation membrane and the hydrogen generated from the first side passes through the second side to remove hydrogen as a product in the methane reforming reaction that occurs on the first side, and the second side Hydrogen can be concentrated.

Methane reforming (MR) carried out in at least one space partitioned by a partition is only hydrogen in the products of Scheme 1 (Steam Methane Reforming, SMR) and/or Reaction Scheme 2 (water-gas shift reaction, WGS) By selectively separating, the reforming efficiency is improved by LeCharlier's equilibrium breakthrough principle, and it can be operated at a lower temperature (550 to 650 °C) compared to the general reforming process (650 to 900 °C).

Through the hydrogen separation membrane, as hydrogen is continuously removed from the reformed synthesis gas, process efficiency is improved and the reaction temperature is reduced according to Le Chatelier's principle. The hydrogen removal characteristics of such a hydrogen separation membrane structure are determined by the hydrogen permeability of the hydrogen separation membrane structure, and in particular, it is necessary to secure a hydrogen separation membrane with excellent performance.

Since the SMR reaction is an endothermic reaction, a method in which one or more of a gas burner, a blowing heater, or an induction method is combined may be applied to supply a heat source.

The gas in the retentate from which hydrogen has been separated and removed is a tail gas, and thermal efficiency can be improved so that the heat generated through the combustion reaction is used for the entire process through the heat exchanger.

In the present invention, the second surface of the tubular hydrogen separation membrane may have the methanation catalyst activity of the following reaction formula 3 for removing CO in the hydrogen-enriched gas that has passed through the hydrogen separation membrane.

[Scheme 3]

CO+ 3H ₂ ↔ CH ₄ + H ₂ O ΔH=-206 kJ/mol

In the present specification, the methanation reaction is a reverse reaction of the steam reforming reaction (SMR) of methane of Scheme 1, and may be represented by Scheme 3, and the methanation catalyst means a catalyst of the methanation reaction.

When the porous support is disposed on the second surface and the palladium-based dense membrane layer is disposed on the first surface, the porous support may be a porous nickel support having a methanation catalytic activity for removing CO.

In one embodiment of the present invention, methane steam reforming reaction (SMR) of Scheme 1 and/or water gas shift reaction (WGS) of Reaction Scheme 2 in the retentate-side (side where hydrogen is not permeated) based on the palladium-based dense membrane is H ₂ , CO and CO ₂ containing gas are formed, and hydrogen-enriched gas is formed while passing through the palladium-based dense membrane, and the methanation catalyst of Reaction Formula 3 on the permeate-side (the side through which hydrogen permeates) based on the palladium-based dense membrane By disposing the active porous nickel support, the hydrogen-enriched gas can be removed with CO in the hydrogen-enriched gas while _{a portion of the concentrated H 2} reacts with a small amount of CO _{to form a small amount of CH 4 .}

All of the CO in the hydrogen-enriched gas that has passed through the palladium-based dense membrane can be completely removed by methanation on the porous nickel support. For example, in the tubular hydrogen separation membrane, a palladium-based dense membrane is disposed on the outside of the tubular or cylindrical porous nickel support, and the hydrogen enriched gas from which CO is removed may be collected in the inner space or pores of the tubular or cylindrical porous nickel support. Therefore, CO selective oxidation (Preferential Oxidation, PrOx) or purification process (PSA, Membrane, etc.) for removing residual CO is unnecessary.

Alternatively, a methanation catalyst is charged into a collector in the reactor that collects hydrogen separated and collected into the inner space of the tubular hydrogen separation membrane, and the hydrogen separated through the hydrogen separation membrane is discharged from the outlet (permeation port) of the reactor. Carbon monoxide concentration can be lowered to 10 ppm or less.

According to an embodiment of the present invention, the membrane reactor equipped with a catalyst inside the membrane module designed to increase the hydrogen recovery rate and capable of chemical reaction is a shell-and-tube type,

The shell is filled with a catalyst for methane reforming reaction and optionally a catalyst for water-gas shift reaction (WGS) and/or a carbon dioxide absorber,

Hydrogen formed by Reaction Equations 1 and 2 from a gas containing methane and water vapor under a catalyst for methane reforming reaction in the shell and optionally a catalyst for WGS is concentrated or separated inside the tube through the tubular hydrogen separation membrane structure,

Optionally, the carbon dioxide formed by Scheme 2 under the catalyst for WGS in the shell may be captured by the carbon dioxide absorbent charged in the shell.

When using a hydrogen separation membrane and a dry carbon dioxide absorbent at the same time (SR-SEMR) in a methane gas reforming reaction (SR) based on Scheme 1 (Steam Methane Reforming, SMR) and Reaction Scheme 2 (water-gas shift reaction, WGS), Reaction Scheme In the products of Schemes 1 and ₂ , not only hydrogen (H 2 ) but also carbon dioxide (CO ₂ ) is selectively removed, so that only hydrogen is removed in the methane gas reforming reaction using only a hydrogen separation membrane without a carbon dioxide absorbent (SR-MR). can be further promoted to maximize process efficiency. In this case, the present invention can provide a high-efficiency hybrid device and process capable of simultaneously performing high-efficiency hydrogen production and carbon dioxide capture while lowering the reaction temperature by simultaneously applying palladium hydrogen separation membrane and dry carbon dioxide absorbent technology to the methane gas wet reforming reaction process. there is.

To elaborate, the two reactions occur consecutively in an atmosphere in which steam is in excess of methane. In the methane wet reforming reaction of Scheme 1, when hydrogen, which is a product, is selectively separated with a separation membrane (Memb.), the forward reaction of Scheme 1 is improved as well as Rather, in the WGS reaction of Scheme 2, if carbon dioxide, a product, is collected using a dry absorbent (Σ(s)) and at the same time, hydrogen, a product thereof, is separated through a separation membrane (Memb.), the forward reaction of Scheme 2 is also improved. Therefore, if the reforming reaction is further improved by simultaneously capturing/separating carbon dioxide and hydrogen, which are the main components of the products of Schemes 1 and 2, occurring in the same reactor space, the reaction temperature is lowered compared to the membrane-enhanced reforming reaction and the Sorption-enhanced reforming reaction. can be significantly lowered. Such a hydrogen separation membrane/carbon dioxide absorbent hybrid reformer technology is a representative example of the present invention. Therefore, in the following, one embodiment of the present invention is often abbreviated as hydrogen separation membrane/carbon dioxide absorbent hybrid reformer technology.

Hydrogen separation membrane / carbon dioxide absorbent hybrid reformer technology (SR-SEMR) according to the present invention, the reforming reaction of Schemes 1 and 2, simultaneously removes hydrogen and carbon dioxide, which are its products, continuously, thereby breaking the thermodynamic equilibrium according to the Le Charlier principle and can be operated at around 500℃. Therefore, 1) the operation efficiency is excellent compared to the traditional methane reforming reactor, 2) the reaction temperature is low at 500°C, so it is possible to configure an economical reactor with medium and low temperature material composition 3) economical process due to the low downstream refining load Easy to operate

In addition, compared to the separation membrane reformer (SR-MR) operated at 300 ° C to 520 ° C, preferably 400 ° C to 500 ° C 1) The reforming temperature can be further reduced by 50 ° C or more due to the acceleration of the forward reaction due to the capture _{of CO 2 as a product.} Fuel consumption is reduced by about 10%, 2) CO and CO ₂ of the retentate part are removed by the carbon dioxide absorbent, so the concentration of unseparated H ₂ , CH ₄ is improved, and the process cost is reduced by about 5% or more This excellent process configuration is possible.

Furthermore, since the hydrogen separation membrane/carbon dioxide absorbent hybrid reformer device and process according to the present invention can be operated at 300° C. to 520° C., preferably 400° C. to 500° C., high-temperature by-product gas at around 500° C. generated in the steelmaking process Phosphorus Coke Oven Gas (COG) can be applied as an _{additional hydrogen production/refining and CO 2 capture device without supplying a special heat source.}

In the hydrogen production and purification apparatus designed to simultaneously perform methane gas-based high-efficiency hydrogen production and carbon dioxide capture according to the present invention, the reaction temperature of Reaction Equations 1 and 2 on the first side of the tubular hydrogen separation membrane, that is, the operating temperature is 300 It may be ℃ ~ 520 ℃, preferably 400 ℃ ~ 500 ℃.

Coke Oven Gas (COG), a by-product gas from the use of coke, has hydrogen and methane as its main components and a gas temperature of around 500 ° C. can be produced, and CO ₂ in COG gas can be captured.

Therefore, the reactor according to the present invention is a methane-containing gas, and it is possible to use a high-temperature by-product gas of 500 ℃ ± 100 ℃ generated in the steelmaking process, and can produce high-purity hydrogen while collecting _{CO 2 in the high-temperature by-product gas.}

According to the present invention, the main core materials of the reactor capable of producing hydrogen and capturing carbon dioxide are (a) a hydrogen separation membrane, (b) a solid carbon dioxide absorbent, and (c) a catalyst for methane reforming.

The catalyst for the methane reforming reaction includes a catalyst for performing a steam reforming reaction (SMR) of methane of Scheme 1 and a catalyst for performing a water-gas shift reaction (WGS) of Reaction Scheme 2, or It may be a catalyst for performing both the steam reforming reaction (SMR) of methane of Scheme 1 and the water gas shift reaction (WGS) of Scheme 2.

_{Ni-based Ni/Al 2} O ₃ catalyst for steam reforming reaction (SMR) is most commonly used. Although noble metal catalysts such as Ru and Pt are expensive, they have high reaction activity and excellent durability, so Ru/Al ₂ O ₃ is being applied as a commercial catalyst. As catalysts for water gas shift reaction (WGS), Fe ₂ O ₃ /Cr ₂ O ₃ and Cu/ZnO/Al ₂ O ₃ catalysts have been commercialized and used.

In the present invention, the catalyst for the methane reforming reaction that can be filled on the first side (eg, in the shell) of the tubular hydrogen separation membrane is any type of catalyst capable of reforming reaction such as pellet form, bead form, foam form and powder form. . More preferably, it may be a catalyst for reforming reaction based on metal foam. If the metal foam catalyst is used, the effect of heat transfer and mass transfer can be maximized, and the hydrogen recovery rate limit due to the concentration gradient, which can be a problem in the tubular membrane, can be overcome. The key to constructing a membrane reactor using metal foam is to overcome the problem of mutual diffusion due to contact between the membrane and the metal foam when the metal foam catalyst is mounted on the outside of the membrane. It can be solved by coating the catalyst after inserting the coating material and the blocking rod.

The metal foam catalyst usable in the present invention is one or more metals selected from the group consisting of aluminum, iron, stainless steel, nickel, iron-chromium-aluminum alloy (Fecralloy), nickel-chromium alloy, copper and copper-nickel alloy. A catalyst for methane reforming may be coated on the surface of the formed metal structure in the form of a foam, but is not limited thereto.

The carbon dioxide absorbent used in the present invention is a dry absorbent that is not a liquid but a solid.

In the hydrogen separation membrane / CO ₂ absorbent hybrid reforming reaction of the present invention, the manufacturing and molding process for _{the CO 2 absorbent must be considered to enable continuous operation as a CO 2} absorption and regeneration process under high-temperature and high-pressure reaction conditions in which moisture is present.

In the present invention, the solid carbon dioxide absorbent may be changed into a stable compound by reacting with carbon dioxide, and may be regenerated into the original compound by degassing the carbon dioxide again in the regeneration reactor.

The shape of the absorbent may be spherical for easy circulating replacement when applying a fluidized bed reactor, and it is preferable to form a porous interior to improve absorption capacity. In addition, it may be required to improve the thermal and physical stability and abrasion resistance of the absorbent.

It is preferable that the carbon dioxide absorbent applicable to the hydrogen separation membrane / CO ₂ absorbent hybrid reformer process of the present invention can selectively remove carbon dioxide generated as a reaction by-product in the synthesis gas composition of high temperature and high pressure. In addition, it is desirable to have a high absorption capacity and a fast absorption/regeneration rate at the same time.

A WGS catalyst or a membrane reactor composed of a WGS catalyst and a CO ₂ absorber can produce cattle in connection with coal, biomass, and waste gasification processes.

On the other hand, a reactor equipped with a tubular hydrogen separation membrane module according to the present invention, as illustrated in FIGS. 5 to 10, is a shell-and-tube type hydrogen production and purification device,

The shell is filled with a catalyst for methane reforming and optionally a WGS catalyst and/or a carbon dioxide absorber,

Hydrogen formed by Reaction Equations 1 and 2 from the gas containing methane and water vapor under the catalyst for the methane reforming reaction in the shell penetrates the tubular hydrogen separation membrane and is concentrated or separated inside the tube,

Carbon dioxide formed by Scheme 2 under the catalyst for methane reforming reaction in the shell may be captured by the carbon dioxide absorbent charged in the shell.

Therefore, the shell-and-tube type hydrogen production and purification apparatus according to the present invention can provide a compact 50 ~ 5,000 Nm ³ /h class small and medium-sized hydrogen production plant.

Since the steam reforming reaction of methane of Scheme 1 occurring in the shell is an endothermic reaction, a tube for exothermic reaction or a heat exchanger for exothermic reaction may be provided at the center.

In the shell-and-tube type membrane reformer, one or more tubes for exothermic reaction or heat exchanger for exothermic reaction disposed inside the reactor, and a plurality of tubular hydrogens arranged in a column shape to the outside of the tube for exothermic reaction or heat exchanger for exothermic reaction It may have a structure including a separation membrane.

In the membrane reforming reactor of the present invention, the upper or lower end of the hydrogen separation membrane for a tube may be fixed to the shell-and-tube type reactor by a tube sheet.

Since the methane reforming reaction of Scheme 1 is a large endothermic reaction, the required heat can be supplied by the catalytic combustion reaction with air of the combustion gas in the tube for the exothermic reaction disposed at the center of the shell-and-tube type reactor.

In the shell-and-tube type membrane reforming reactor of the present invention, the temperature (T _{1 ) of the tube for exothermic reaction or the heat exchanger for exothermic reaction is higher than the temperature (T 2} ) of the catalyst layer filled in the shell, and for exothermic reaction disposed in the center As heat moves radially from the tube or the heat exchanger for exothermic heat to the outside, synthesis gas may be formed by the endothermic reaction by the catalyst for methane reforming in the shell.

That is, the shell-and-tube type membrane reforming reactor according to an embodiment of the present invention has a heating means therein so that heat is transferred from the inside (T ₁ ) to the outside (T ₂ , T ₁ > T ₂ ), Excellent thermal efficiency. In this case, the heating means may be provided with a combustion catalyst to supply heat through an exothermic reaction, but may also include a heat transfer means (T ₁ ). The tube for the exothermic reaction may be filled with at least one catalyst capable of catalyzing the exothermic reaction. A catalyst capable of catalyzing the exothermic reaction usable in the present invention includes a combustion catalyst. Specifically, as a combustion catalyst usable in the present invention, a catalyst in which Pt/Rh is supported on cordierite may be used, but the present invention is not limited thereto.

In the shell-and-tube membrane reforming reactor of the present invention, the lower end of the tubular hydrogen separation membrane utilizes the metal tube characteristics to connect a metal tube and a tube sheet welded to the end of the filter or use a metal fitting to seal. . In addition, the tube sheet, the module cover, and the module body equipped with the separator can be assembled in a flange manner to complete the unit module.

The main use of the reforming reactor equipped with the tubular hydrogen separation membrane module according to the present invention described above can be used in processes that require low-cost hydrogen, such as hydrogen-reduced iron and steel. Therefore, it is possible to reduce _{CO 2} emission by 15% in the hydrogen reduction ironmaking method. In addition, it can be used in a hydrogen station where greenhouse gas reduction is possible.

In addition, the present invention provides a method for producing hydrogen-enriched gas while simultaneously performing hydrogen production and preferably carbon dioxide capture from a gas containing methane and water vapor in a reforming reactor equipped with a tubular hydrogen separation membrane module according to the present invention.

In this case, the reactant methane-containing gas may be natural gas, shale gas, or coke oven gas (COG). In particular, it is possible to produce high-purity hydrogen while capturing _{CO 2} in COG gas from Coke Oven Gas (COG) whose main components are hydrogen and methane.

Furthermore, the hydrogen-enriched gas as a product may be used as a fuel for a fuel cell or as hydrogen for ammonia synthesis, an oil refining process, a smelting process, a polysilicon manufacturing process, a semiconductor manufacturing process, or an LED manufacturing process.

Furthermore, the present invention provides a separation membrane module according to the present invention; And a fuel cell using the hydrogen enriched gas provided from the separation membrane module as a fuel may provide an electric energy generating device interlocked.

When the methanation reaction of Reaction Formula 3 is linked in the pores of the porous nickel support located on the permeate-side through which hydrogen permeates after the hydrogen permeation membrane process in the palladium-based dense membrane according to one embodiment of the present invention, the palladium-based dense membrane is defective It can be used as a fuel for a PEMFC fuel cell using a catalyst in which CO acts as a catalyst poison without a separate purification device because the concentration of CO transmitted through (defect) can be controlled to 20ppm or less.

According to the present invention, a reactor equipped with a tubular hydrogen separation membrane module has excellent mass transfer due to easy formation of turbulence through spiral fluidization, minimizes heat loss required for reaction/separation, and improves process efficiency, as well as tubular hydrogen separation membrane by using the space within which is mounted a shell in the partition wall dual to the 1 ^st room and 2 ^nd room according to separator length may increase the hydrogen recovery rate to overcome the disadvantages that do not exhibit the membrane up performance in reduced hydrogen partial pressure difference.

1 is a conceptual diagram for explaining the principle of operation of a separation membrane module having a tubular hydrogen separation membrane according to an embodiment of the present invention.
2 to 4 are examples of configuring the two-stage tubular hydrogen separation membrane module of FIG. 1 using a partition wall.
5 to 10 are various embodiments of a membrane reactor to which the working principle of a tubular hydrogen separation membrane module is applied according to an embodiment of the present invention.
11 is an embodiment in which two or more tubular hydrogen separation membrane modules designed to increase the hydrogen recovery rate are connected in series according to an embodiment of the present invention.
12 is a process diagram illustrating a conventional separation cascade method in which a permeation port and a feed port are connected to increase the purity of hydrogen.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are only for clearly illustrating the technical features of the present invention, and do not limit the protection scope of the present invention.

When the principle of action according to one embodiment of the present invention of FIG. 1 is applied to the design of a tubular hydrogen separation membrane, in each space divided into ^{a first space (1 st} room) and a second space (2 ^{nd room) through a partition wall, the outside} _{(outside) Hydrogen partial pressure at the first side (P outside} ) > Hydrogen partial pressure at the second side (P _inside ) based on the tubular hydrogen separation membrane that allows hydrogen to pass from the first side to the second side, and the hydrogen separation membrane A two-stage tubular hydrogen separation membrane module can be manufactured by disposing one or more tubular hydrogen separation membranes for discharging the hydrogen that has passed through the open portion on the second side, as illustrated in FIGS. 2 to 4 . In the tubular hydrogen separation membrane module according to an embodiment of the present invention of FIGS. 2 to 4, (i) a reactant (eg, natural gas + steam, etc.) or hydrogen required for hydrogen production as a feed configured on the upper side of the module Supplying a mixed gas (eg, H ₂ + CO ₂ , CH _4, CO, steam, O _2, etc.); (ii) generating a gas flow that forms a turbulence in the longitudinal direction of the tubular separator by generating spiral fluidization when gas is introduced into the supply unit; (iii) after the first hydrogen separation from 1 ^st room through the first area and a second partition wall that distinguishes the second space to the tubular membrane longitudinally remaining residual hydrogen is separated from the 2 ^nd room it is trapped in the lower collector non-separated gas is A retentate-side release step can be performed. At this time, the carbon monoxide concentration can be lowered to 10ppm or less by selectively charging the methanation catalyst to the collector.

Hereinafter, a separation membrane reactor having a tubular hydrogen separation membrane module according to an embodiment of the present invention of FIGS. For a process using this, the present invention will be described in more detail through embodiments of a membrane reactor having a tubular hydrogen separation membrane module schematically illustrated in FIGS. 5 to 10 . These Examples are for explaining the present invention in more detail, and the scope of the present invention is not limited by these Examples.

8 schematically shows the structure of a tubular hydrogen separation membrane module in a shell-and-tube type membrane reactor, and the reforming reaction of methane gas and high-purity hydrogen in a shell-and-tube type hydrogen separation membrane/carbon dioxide absorbent hybrid reformer (SEMR) It is a schematic diagram showing a device in which production and carbon dioxide capture occur simultaneously.

The membrane reactor having a tubular hydrogen separation membrane module designed to increase the hydrogen recovery rate according to the present invention can be used as a membrane reforming reactor in which the catalytic methane reforming reaction and the hydrogen separation membrane reaction through a Pd-based membrane occur simultaneously.

In the membrane reactor, the tubular palladium membrane and the commercial ruthenium catalyst may be mounted in contact with each other in the cell space of the divided reactor.

The membrane reactor of the present invention may be a shell-and-tube type membrane reforming reactor, and in the cell space of the reactor partitioned by a partition wall, methane steam reforming reaction (SMR) of Scheme 1 and water gas shift reaction (WGS) of Scheme 2 ), a catalyst for the methane reforming reaction and a carbon dioxide absorbent are provided.

[Scheme 1]

CH ₄ + H ₂ O → CO + 3H ₂

[Scheme 2]

CO + H ₂ O → CO ₂ + H ₂

In addition, the shell-and-tube type membrane reactor, (i) a palladium-based dense membrane layer; a diffusion barrier layer; and a tubular hydrogen separation composite membrane having a porous nickel support having a methanation catalytic activity on the permeate-side through which hydrogen is permeated to remove CO in the hydrogen-enriched gas that has passed through the palladium-based dense membrane; and (ii) a tube for exothermic reaction or a heat exchanger for exothermic reaction, arranged in the center.

As shown in FIG. 8 , the shell-and-tube type membrane reactor includes means for supplying the methane-containing feed gas from the top into the first space of the partitioned shell of the shell-and-tube type membrane reactor, and to the bottom of the reactor. may be provided with a means for evacuating the concentrated or separated hydrogen from the product fluid formed by the catalyst for methane reforming in the reactor shell through the tubular hydrogen separation membrane.

Looking at the fluid flow in the shell-and-tube type membrane reactor, first, the methane-containing gas and steam are supplied to ^{the first space (1 st room) partitioned through the partition wall in the shell-and-tube type membrane reactor, and the shell-and-} After being supplied through a means for supplying from the top of the tubular membrane reactor into the reactor shell and uniformly distributed into the shell through a distributor, the reforming reaction occurs due to the catalyst for the methane reforming reaction charged inside the shell, and a fluid containing carbon dioxide and the like. Carbon dioxide from the generated fluid is then collected by a dry carbon dioxide absorbent filled with a catalyst for methane reforming in the shell, and hydrogen is selectively passed into the tubular hydrogen separation membrane, and a permeate stream containing high concentration hydrogen (permeate stream) ) and hydrogen-depleted fluid, which is separated into two types of exhaust gas, respectively, and the unreacted fluid from which some or all of hydrogen and carbon dioxide have been removed is discharged through the exhaust gas exhaust means at the top, and at the bottom The hydrogen-rich fluid is evacuated through a permeate gas exhaust means.

The shell-and-tube membrane reactor of the present invention is a shell in (i) hydrogen in synthesis gas formed by a catalyst for methane reforming, (ii) hydrogen in a product of a water gas conversion reaction, and/or (iii) methane as a reactant Hydrogen in the containing gas (eg, COG) penetrates the tubular hydrogen separation composite membrane and is concentrated or separated into the tubular hydrogen separation composite membrane, and in the shell (i) carbon dioxide formed in the water gas shift reaction (WGS) of Reaction Formula 2, and / Or (ii) carbon dioxide in the reactant methane-containing gas (eg, COG) may be captured by the carbon dioxide absorbent particles (s) together with the catalyst for the methane reforming reaction in the shell. Therefore, hydrogen and carbon dioxide are separated through the tubular hydrogen separation composite membrane at the same time as the methane gas reforming reaction, thereby destroying the thermodynamic equilibrium according to LeCharlier's law to promote both the forward reactions of Schemes 1 and 2, especially the process efficiency of Scheme 1 can be maximized. For this reason, even at a low temperature of 300 ~ 600 ℃, it is possible to secure the conversion rate above the thermodynamic equilibrium of Scheme 1.

For example, in the shell-and-tube type membrane reactor, natural gas and steam supplied into the reactor shell undergo a primary methane reforming reaction in the first space. Subsequently, the methane-containing exhaust gas of the first space is supplied to the second space, and the methane reforming reaction occurs secondarily by the reforming catalyst charged in the shell of the second space. In the fluid containing hydrogen and carbon dioxide, etc. generated at this time, hydrogen is selectively separated into the inside of the tubular hydrogen separation membrane, while carbon dioxide is captured by the carbon dioxide absorbent particles (s) together with the catalyst for the methane reforming reaction in the shell, natural gas reforming By removing hydrogen and carbon dioxide in the shell where the reaction takes place, not only high-purity hydrogen production and carbon dioxide capture are possible at the same time, but also the efficiency of the natural gas reforming reaction is improved, so that the production efficiency of these gases is excellent and natural gas with similar efficiency even at a lower temperature A reforming reaction may be carried out. For example, the reactor can be operated with a similar reaction efficiency by lowering the temperature of the reactor by 100° C. or more. In addition, by destroying the thermodynamic equilibrium according to LeCharlier's law, it is possible to secure a conversion rate above the thermodynamic equilibrium even at a low temperature of 300 to 600 ℃, and to lower the temperature of the reformer, which was operated from 650 to 900 ℃, to 300 to 650 ℃. It has excellent operating efficiency and low reformer temperature, so the reactor can be constructed with materials for medium and low temperature, making it possible to construct an economical reactor. Furthermore, since it is possible to produce high-purity hydrogen and capture carbon dioxide at the same time as the reaction, the downstream hydrogen purification process and carbon dioxide capture process can be excluded, so that a compact process configuration is possible as shown in FIGS. it's technology That is, when using a shell-and-tube type membrane reforming reactor equipped with a tubular hydrogen separation membrane module and a carbon dioxide absorber according to the present invention in a clean energy production technology using natural gas, high purity hydrogen can be produced and carbon dioxide can be separated at the same time. A compact process configuration is possible as well as economical operation.

In addition, since the SMR reaction is an endothermic reaction, it is possible to use a combination of at least one of a gas burner, a blowing heater, and induction to supply a heat source.

As shown in FIG. 8, the membrane-absorbent hybrid system can maximize reaction efficiency by continuously removing hydrogen and carbon dioxide, which are products, according to Le Chateller's principle in the SMR reaction.

In addition, the gas in the retentate except for the high-purity hydrogen separated after the reaction is a tail gas can improve the thermal efficiency so that the heat generated through the combustion reaction is used for the entire process through the heat exchanger.

Claims (27)

As a separation membrane module having a tubular hydrogen separation membrane designed to increase the hydrogen recovery rate,
The first space (1 ^st room), the second space (2 ^nd room), . , ^{divide the n th} room (n ≥ 2),
In each space, hydrogen partial pressure at the first side (P _outside ) > hydrogen partial pressure at the second side ( P _inside ) and a separation membrane module characterized in that one or more tubular hydrogen separation membranes are disposed to discharge hydrogen that has passed through the hydrogen separation membrane through the open part on the second side. The method of claim 1, wherein the length of the first tubular hydrogen separation membrane disposed in ^{the first space (1 st} room), the length of the second tubular hydrogen separation membrane disposed in the second ^{space (2 nd room), ...} , and than the hydrogen recovery rate in the tubular hydrogen separation membrane having a length corresponding to the sum of the lengths of the nth tubular hydrogen separation membrane disposed in the ^{n th room,}
Hydrogen recovery amount in the first tubular hydrogen separation membrane, hydrogen recovery amount in the second tubular hydrogen separation membrane, … , and a separation membrane module characterized in that the sum of the hydrogen recovery amount in the nth tubular hydrogen separation membrane is larger. According to claim 1, wherein the total amount of hydrogen recovery in the separation membrane module having a tubular hydrogen separation membrane, the hydrogen recovery amount in the first stage module composed of the first tubular hydrogen separation membranes disposed in the first space, in the second space Hydrogen recovery amount in the second stage module composed of the arranged second tubular hydrogen separation membranes, ... , and a separation membrane module characterized in that it is the sum of the hydrogen recovery amount in the n-th stage module composed of the n-th tubular hydrogen separation membranes disposed in the n-th space. The method according to claim 1, wherein the gas continuously flowing through each space separated through the partition wall from the module inlet and discharged out of the reactor is a retentate gas from which hydrogen has been removed through a hydrogen separation membrane,
Designed to distinguish a retentate port from which the retentate gas flow from which hydrogen has been removed through the hydrogen separation membrane is discharged and an outlet through which hydrogen collected in the inner space of the tubular hydrogen separation membrane passing through the hydrogen separation membrane is discharged (permeation port) A separation membrane module characterized in that. According to claim 1, Residual hydrogen remaining after the primary hydrogen separation in the first space is separated in the second space,
Separation membrane module, characterized in that the hydrogen separated through the hydrogen separation membrane in the first space and the second space is collected by a collector in the reactor, and the unseparated residual gas is discharged through a retentate port. According to claim 1, wherein two or more separation membrane modules having a tubular hydrogen separation membrane designed to increase the hydrogen recovery rate are connected in series, and an outlet (retentate port) of the residual gas from which hydrogen has been removed from the upstream membrane module is the rear end (downstream) Membrane module characterized in that it is connected to the inlet (feed port) of the membrane module. The separation membrane module according to claim 1, wherein the helical fluidization is generated in the gas flow supplied to the first space through the module inlet (feed port) to form turbulence around the tubular hydrogen separation membrane. The method according to claim 1, wherein the separation membrane module inlet is disposed on the upper side or upper side of the separation membrane module in order to generate a downward spiral fluidization in the gas flow supplied to the first space through the module feed port,
A separation membrane module characterized in that it flows in a countercurrent upward direction into the second space after flowing through the first space through a descending spiral fluidization. The separation membrane module according to claim 8, wherein the upper portion of the first space starting from the top of the separation membrane module where the module feed port is disposed is in the form of a cone or a truncated truncated cone in order to efficiently generate a descending spiral fluidization. . The method of claim 1, wherein the fluid supplied through the module inlet is introduced into the first space by giving a vortex flow, and is introduced while rising countercurrently into the second space by the vortex effect in the first space. make it,
Separation membrane module, characterized in that the swirling flow in the first space is driven so that hydrogen separation occurs while winding the tubular hydrogen separation membrane. The separation membrane module according to claim 1, characterized in that it is a shell-and-tube type module having tubular hydrogen separation membranes. The separation membrane module according to claim 1, wherein the one or more partition walls are arranged concentrically inside the shell-and-tube module, and a tubular hydrogen separation membrane is provided in a space separated through the partition wall. The separation membrane module according to claim 1, wherein when oxygen is included in the gas supplied through the module inlet, an inert gas is additionally supplied to prevent an explosion due to hydrogen combustion. The separation membrane module according to claim 1, wherein the hydrogen separation membrane is a palladium-based hydrogen separation membrane. According to claim 1, wherein the hydrogen separation membrane is a palladium-based dense layer; optionally a diffusion barrier layer; and a hydrogen separation membrane on which a porous support is laminated. The separation membrane module according to any one of claims 1 to 15, wherein a reactant or hydrogen-containing mixed gas required for hydrogen production is supplied through a module feed port. [16] The membrane module according to any one of claims 1 to 15, wherein the second surface of the hydrogen separation membrane has a methanation catalytic activity for removing CO in the hydrogen-enriched gas that has passed through the hydrogen separation membrane. 16. The method of any one of claims 1 to 15, wherein a methanation catalyst is charged in a collector in a separation membrane module for collecting hydrogen separated and collected into the inner space of the tubular hydrogen separation membrane, and separation through the hydrogen separation membrane A separation membrane module characterized in that the carbon monoxide concentration is lowered to 10 ppm or less at the permeation port of the module through which the hydrogen is discharged. As a separation membrane reactor in which a catalyst is mounted inside the separation membrane module according to any one of claims 1 to 15 to enable a chemical reaction,
In a membrane reactor equipped with a hydrogen separation membrane module designed to increase the hydrogen recovery rate, the hydrogen generation reaction by the catalyst filled in the shell space separated by the partition wall and the hydrogen separation of the product hydrogen through the Pd-based membrane occur simultaneously,
A catalyst installed in a shell space separated by a partition wall, (i) a reforming catalyst, (ii) a reforming catalyst and a catalyst for water-gas shift reaction (WGS), (iii) a reforming catalyst and a CO ₂ adsorbent, (iv) a reforming catalyst, a catalyst for water gas conversion reaction, and a CO ₂ adsorbent, (v) a catalyst for water gas conversion reaction, and (vi) a catalyst for water gas conversion reaction and a CO ₂ adsorbent. A method for producing hydrogen in the separation membrane module according to any one of claims 1 to 15. A method for producing concentrated hydrogen from a methane-containing gas in the separation membrane reactor according to claim 19, comprising:
A first step of performing a methane reforming reaction in at least one space partitioned by a partition; and
A second step of separating hydrogen synthesized in the methane reforming reaction through a tubular hydrogen separation membrane disposed in a space in which the methane reforming reaction is performed,
The methane reforming reaction takes place on the first side of the hydrogen separation membrane, and the hydrogen generated from the first side passes through the second side to remove hydrogen as a product in the methane reforming reaction that occurs on the first side, and hydrogen is added to the second side. A method for producing hydrogen characterized by concentration. 22. The method of claim 21, wherein the gas in the retentate from which hydrogen is separated and removed is a tail gas, and the heat generated through the combustion reaction is used for the entire process through a heat exchanger to improve thermal efficiency. 22. The method of claim 21, wherein the methane-containing gas is provided from a high-temperature by-product gas of 500°C ±100°C generated in the ironmaking process, and the method for producing high-purity hydrogen is characterized by producing high-purity hydrogen while capturing _{CO 2 in the high-temperature by-product gas.} . 22. The method of claim 21, wherein the methane-containing gas is natural gas, shale gas, or Coke Oven Gas (COG). 22. The method of claim 21, wherein the hydrogen-enriched gas is used as a fuel for a fuel cell or as hydrogen for ammonia synthesis, an oil refining process, a smelting process, a polysilicon manufacturing process, a semiconductor manufacturing process, or an LED manufacturing process. 22. The method of claim 21, wherein high purity hydrogen is produced while capturing _{CO 2} in the COG gas from coke oven gas (COG) whose main components are hydrogen and methane. The separation membrane module according to any one of claims 1 to 15; and a fuel cell using the hydrogen enriched gas provided from the separation membrane module as a fuel.

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