KR100855772B1 - Adsorbent to adsorb the sulfurour gas contained in fuel gas, and desulfurization equipement in fuel cell system using such adsorbent - Google Patents

Abstract

The present invention relates to a sulfur removal component contained in fuel gas and a desulfurization apparatus of a fuel cell system using the same, wherein the micropore is 70% or more, the specific surface area is 1,000 m 2 / g or more, and the hardness is 95% or more. Activated carbon having a particle diameter of 12 × 16 to 4 × 6 mesh, or a mixture of activated carbon to zeolite having a ratio of activated carbon to zeolite in a mixture of activated carbon and zeolite with a ratio of 2: 8 to 8: 2, NaOH, Na ₂ CO _3, KOH, KI , I _2, CuO, Fe ₂ O _3, ZnO, Desulfurization apparatus of a fuel cell system, characterized in that the sulfur component removal member formed by attaching one selected from Cucl _{2 ·} 2H ₂ O and FeCl ₂ , and the sulfur component contained in the fuel gas is desulfurized by using the sulfur component removal member. It is about providing.

Desulfurization, fuel cell

Description

Sulfur removal member in fuel gas and desulfurization apparatus of fuel cell system using same {Adsorbent to adsorb the sulfurour gas contained in fuel gas, and desulfurization equipement in fuel cell system using such adsorbent}

1 is a block diagram of a fuel cell system having a desulfurization apparatus of the present invention;

Figure 2 is a schematic diagram of the adsorption experiment apparatus for the desulfurization apparatus of the fuel cell system of the present invention.

<Explanation of symbols for main parts of drawing>

1: desulfurization apparatus 2: reformer

6 stack 12 controller

30: adsorption experiment apparatus 100: fuel cell system

The present invention relates to a sulfur component removing member for removing sulfur components contained in fuel gas, and a fuel gas desulfurization apparatus of a fuel cell system using the same.

A fuel cell is a device that directly converts energy of a fuel directly. Generally, a fuel cell is attached to a porous anode and a cathode with a polymer electrolyte membrane interposed therebetween. An electrode or fuel electrode) is supplied with a fuel gas containing hydrogen or hydrogen, while an oxidizing gas containing oxygen is supplied to the cathode (reduction electrode or cathode), whereby electrochemical oxidation of hydrogen occurs at the anode, and oxygen at the cathode. Electrical reduction occurs, which causes electricity and heat to be generated due to the movement of the generated electrons. In such a fuel cell, when the electrolyte membrane of the stack is dried, the conductivity of hydrogen ions (H +) decreases or the electrolyte membrane shrinks, so that the contact resistance between the membrane and the electrode increases, which may degrade the stack performance. When fuel or air is supplied, water is supplied together in the form of water vapor.

The fuel gas used in the fuel cell includes low hydrocarbons such as methane, ethane, ethylene, propane and butane, and fuels such as city gas, LP gas, and natural gas such as domestic and industrial fuels. In the battery system, a hydrogen component is manufactured from the fuel gases as described above and used as a raw material.

Among the methods for producing hydrogen from fuel gas, a widely used method is steam reforming, which is a nickel-based (Ni-based) or ruthenium-based (Ru-based) method for producing hydrogen from lower hydrocarbons using steam. Using a reforming catalyst. However, the reforming catalyst used in the steam reforming method has a problem in that the performance is significantly lowered when poisoned by sulfur compounds, and once it is poisoned, it is difficult to recover to its original state, and thus, it has to be replaced. There is a problem.

On the other hand, the fuel gas is artificially contained an odorous substance of the sulfur component gas to easily identify the gas leakage for safe storage, transport, use and the like. In other words, gaseous fuel is highly flammable compared to liquid fuel, and in an enclosed space, it can cause fatal damage to human body or facility due to strong explosion, whereas its color is odorless and can not detect gas leakage. In order to easily detect the leak, sulfide gas having a unique smell is added to the gaseous fuel as an odorant.

As widely used odorants, mercaptans include ethyl mercaptan, t-Buthyl mercaptan, isopropyl mercaptan, normal propyl mercaptan, sec-butyl mercaptan, and sulfides. Examples thereof include tetrahydrothiopene, dimethyl sulfide, methyl ethyl sulfide, and the like. One or two or more of these materials are mixed and added to the gaseous fuel. As odorants mainly used in Korea, liquefied petroleum gas (LPG) is used as ethylmercaptan, CP630 (titanium butylmercaptan, dimethyl sulfide, methylethyl sulfide, pentane, hexane) and natural In the case of gas (LNG), a butyl butyl mercaptan and tetrahydrothiophene are mixed and used. For reference, in the experiment for the present invention, as the odorant, t-Buthyl mercaptan (hereinafter referred to as "TBM") and tetrahydrothiopene (hereinafter referred to as "THT") were used.

As described above, when a fuel gas containing sulfur is used as a raw material of a fuel cell, as described above, a reforming catalyst such as nickel (Ni) or ruthenium (Ru) is poisoned by the sulfur. Problems arise.

In order to solve this problem, the use of activated carbon can be considered, but since activated carbon alone has low sulfur removal efficiency, a large amount of activated carbon must be used to remove sulfide gas. In addition, since the activated carbon must be replaced frequently, there is little practical applicability. In addition to using activated carbon, a desulfurization facility may be separately installed to remove and remove sulfur components contained in fuel gas. However, since such desulfurization facilities require a lot of cost, the fuel cell business using fuel gas may have a lower economic efficiency. do.

The present invention was devised to overcome the above problems, and an object of the present invention is to enable efficient removal of sulfur components contained in fuel gas at room temperature, thereby enabling fuel cell business using fuel gas to be activated. To ensure that That is, the present invention is to develop a room temperature adsorption agent having a large adsorption capacity for sulfur component gas, to provide a room temperature adsorption desulfurization apparatus, and to apply such a desulfurization apparatus to a fuel cell system.

The present invention develops a sulfur component removing member capable of adsorbing and removing sulfur components contained in methane, ethane, ethylene, propane, butane, city gas, liquefied petroleum gas (LPG) or natural gas (LNG). The present invention provides a desulfurization apparatus for a fuel cell system using the sulfur component gas removing member.

Sulfur component gas removing member of the present invention is any one of activated carbon or a mixture of activated carbon and zeolite, sodium hydroxide, sodium carbonate, potassium hydroxide, potassium iodide, iodine, copper oxide, iron oxide, coral zinc, copper chloride, iron chloride It is formed by adhering two or more compositions. Since the sulfur component removing member of the present invention is capable of adsorbing a large amount of sulfur component at room temperature, the sulfur component removing member can provide a highly efficient and economical desulfurization apparatus for a fuel cell system.

Since the sulfur removing member of the present invention has the ability to adsorb a large amount of sulfur gas at room temperature, in order to do so, the activated carbon or zeolite used in the present invention should satisfy the conditions shown in Table 1 below.

[Table 1] Optimal Requirements for Sulfur Component Gas Removal Member in Desulfurization System

Equipment condition standard  1. Virtual activated carbon with well pore size Micro pore more than 70%  2. Large specific surface area 1,000㎡ / g or more  3. High mechanical strength Hardness (HD) 95% or more  4. No impurities Low ASH, Fe, TS, etc.  5. Narrow particle size 12x16, 4x6 MESH  6. Affinity with impregnation solution -  7. High chemical reactivity -

Activated carbon or zeolite is classified into gas phase and liquid phase according to its use. Usually, 70% or more of micro pores are developed for vapor phase depending on the pore size. On the other hand, the liquid uses more macro pores than micropores. The activated carbon for gaseous phase has a specific surface area of approximately 1,000㎡ / g due to the development of internal pore structure.

Activated carbon or zeolite used in the sulfur component gas removing member of the present invention is preferably used under the conditions as shown in Table 2.

[Table 2] Raw materials, size and shape of activated carbon and zeolite

division raw materials Type size Etc One Coal Pellet 1.5 mm 2 Coal Pellet 4 mm 3 Coal Granule 8 x 12 Calgon 4 Coal Granule 8 x 12 Calgon Acid Treatment 5 Coconut shell Granule 8 x 12  6 Zeolite + Activated Carbon (zeolite: activated carbon) 2: 8 -  4-5mm 5: 5 - 8: 2 -

Among the components constituting the sulfur removing member, activated carbon has a high surface area in which the microcrystals of the graphite structure are independently dispersed and the methylene ring portion coexists, and thus may serve as a highly dispersed carrier. Depending on the structure of the carrier, the substance to be attached is different, and its shape is also different. Therefore, on the condition that the above-mentioned activated carbon and zeolite satisfy the condition of equilibrium, catalysis by the addition of activated carbon or zeolite and the impregnation is expressed and doubled.

In general, activated carbon is used for the absorption and removal of sulfur components in the odorant facility management, but the physical adsorption power of the activated carbon itself is not expected to be more effective than the adsorption of low concentration odorant. In the experiment of the present invention by maximizing the adsorption power of sulfur components by attaching metals, organic compounds and the like to the activated carbon.

In the present invention, two types of metals and organic compounds are selected as the impregnated material for impregnating activated carbon, and specifically, the materials shown in Table 3 below are selected as the impregnated materials.

[Table 3] Impregnated Material

division Impregnated substance Elimination Synthetic conjugation NaOH Na ₂ CO ₃ KOH -TBM. (30%), the main component of odorant, is weakly acidic and removes acid gas. KI I ₂ -Used as sulfide remover-Used as hydrogen sulfide remover  Impingement catalyst action CuO Fe ₂ O ₃ ZnO -Desulfurization catalyst by metal oxides-Acts as sulfur remover Cucl _{2 ·} 2H ₂ O Fecl ₂ -Odor-removing substance-Catalyst used for desulfurization

 Sulfur component removing member of the present invention is a material such as that in Table 3 is attached to the activated carbon, zeolite or a mixture thereof. As such, when impregnating the substances of Table 3 on the activated carbon or zeolite, an impregnation method, a sublimation method, or a spray method may be used. Any of these methods may be used, but a method that can be easily used generally Impregnation method. In the embodiment of the present invention by the impregnation method to remove the sulfur component by impregnating the substance of Table 3 on the activated carbon or a mixture of activated carbon and zeolite. Of course, even if any of the impregnation method, the sublimation method or the spray method is used, there is no significant difference in the efficacy of the sulfur component removing member produced thereby.

In the production of the sulfur component removing member of the present invention, the impregnation step and the drying (oxidation) step are very important processes, and the storage state after the impregnation of the metals or organic compounds with activated carbon or zeolite also has a great effect on performance. Therefore, in the preparation of the sulfur removing member of the present invention, the impregnated solution concentration, viscosity, affinity, impregnated temperature, impregnated aqueous solution, addition order, and drying temperature may influence the performance of the impregnated activated carbon or mixture of activated carbon and zeolite. Can be.

As described above, the sulfur component removing member of the present invention may be any of sodium hydroxide, sodium carbonate, potassium hydroxide, potassium iodide, iodine, copper oxide, iron oxide, zinc zinc, copper chloride, and iron chloride in a mixture of activated carbon or activated carbon zeolite. One or two or more compositions formed by impregnation may be prepared by the following process.

First step: This step is a step of washing and drying activated carbon or zeolite in airtight storage. Activated carbon and zeolite are formed in a number of voids therein, so the specific surface area is very large, and the present invention utilizes these properties of these materials. It is necessary to remove any impurities or moisture that are present or adhered to. The reason why the activated carbon or zeolite is handmade and dried in the present step is also performed to remove impurities and moisture that are permeated into the pores of the materials. In the drying after washing with water, it is preferred to first dry at room temperature for about 24 hours and to dry at about 100 ° C for about 24 hours. This is because drying efficiency at the high temperature immediately after washing may decrease the drying efficiency.

Second step: This step is a step of producing activated carbon or zeolite into powder of a certain size and screening it. In order to maximize the specific surface area of the activated carbon or zeolite and prevent it from being finely divided, the activated carbon or zeolite may be screened at a predetermined size, preferably 4x6 mesh, in size.

Third step: This step is a step of preparing an aqueous solution of an attached substance. In preparing an aqueous solution of the impregnated material using the impregnated materials listed in Table 3 above, it is preferable to prepare the impregnated material solution by mixing the impregnated material with water so as to have a ratio of 5 to 70 by volume.

Fourth step: This step is a step of impregnating an activated carbon or a mixture of activated carbon and zeolite in an aqueous solution of an impregnated substance so that the impregnated substance is impregnated with activated carbon or zeolite. In this case, the mixing ratio is preferably set to volume ratio of activated carbon (or mixture of activated carbon and zeolite): aqueous solution = 1: 0.8 to 1.05, preferably 1: 1.2. It is necessary to stir the mixture well in order for the adhesive to adhere well to the activated carbon or zeolite.

5th process: This process removes a foreign material by passing the mixture of a regular process through a filter, and can remove this process depending on a situation.

6th step: This step is to finish the product by drying, and after filtering the foreign matter in the electric process, the activated carbon or zeolite to which the impregnated material is impregnated is removed, and the moisture is about 3 to 10%, preferably about Dry at room temperature until it reaches about 5%. When the drying is completed, the fine powder contained therein is filtered, dust is removed, and then kept closed to complete the manufacture of the sulfur component removing member of the present invention.

On the other hand, in the sulfur component removing member of the present invention prepared by the method as described above, the adsorption amount of the odorant varies depending on the type of activated carbon, the mixing ratio of the active carbon and zeolite, the type of the impregnated substance, etc. The adsorbent adsorption amount is as shown in Table 4 below.

[Table 4] Desulfurization performance analysis results by type of sulfur component gas removing member of the present invention

Number Sample [carrier, BET (m ² / g), impregnation concentration] Adsorption amount (mgS / g) TBM THT One Active Carbon (Virgin) 18.40 50.54 2 Coal, BET 1000, Na ₂ CO ₃ 5% 29.90 78.97 3 Coal, BET 900, Na ₂ CO ₃ 5% 25.76 60.01 4 Coconut, BET 1000, Na ₂ CO ₃ 5% 46.01 134.24 5 Coconut, BET 1100, Na ₂ CO ₃ 5% 50.61 134.24 6 Coal, BET 900, NaOH 5% 23.92 56.86 7 Coal, BET 900, CuO 5% 27.60 75.02 8 Coal, BET 900, KOH 5% 25.30 90.81 9 Coal, BET 1000, CuCl ₂ 5% 41.41 71.07 10 Coal, BET 900, CuCl ₂ 5% 43.71 75.02 11 Coconut, BET 1000, CuCl ₂ 5% 62.11 110.55 12 Coconut. BET 1100, CuCl ₂ 5% 46.01 86.86 13 Activated Carbon + Zeolite, Na ₂ CO ₃ 5% 45.00 110.05 14 Activated Carbon + Zeolite, CuCl ₂ 5% 55.10 105.05 15 Coconut. BET 2,000, CuCl ₂ 5% 93.17 165.83 16 Coconut, BET 2,000, Na ₂ CO ₃ 5% 69.02 201.36 17 Coconut. BET 2,500, CuCl ₂ 5% 108.70 193.46 18 Coconut, BET 2,500, Na ₂ CO ₃ 5% 80.52 234.92

As shown in Table 4, the higher the specific surface area (BET No.) such as activated carbon, the higher the concentration of the impregnated substance, the better the adsorption capacity of the odorant. However, considering economics, it is difficult to raise it at all.

On the other hand, in the various sulfur component removal member of Table 4, in the case of 5 and 11 (in consideration of the specific surface area and the concentration of the binder), the adsorption capacity of the odorants TBM and THT was measured very high, mixed them When used, it can bring about a desirable effect. That is, in case of No. 5 (coconut activated carbon, specific surface area 1100, 5% Na ₂ CO ₃ impregnated substance), TBM adsorption amount was 50.61 and THT adsorption amount was 134.24. In the case of activated carbon, specific surface area 1000, and impregnated material CuCl ₂ 5%), TBM adsorption amount was 62.11 and THT adsorption amount was 110.55, which is superior to the others. Therefore, by using these mixtures, both the adsorption amount to TBM and THT can be increased. However, in general, the odorant components contained in natural gas are about 70% and 30% of THT and TBM, respectively, so that the mixing ratio of Nos. 5 and 11 is preferably about 7: 3.

On the other hand, as shown in the above table, in the case of using a mixture of activated carbon and zeolite, the adsorption amount for each odorant is quite high.

The sulfur removing member of the present invention may be used for various purposes and purposes, but its use value is higher in a fuel cell using fuel gas. That is, by applying the sulfur component gas removing member of the present invention to the desulfurization apparatus of the fuel cell system to remove the sulfur component, it is possible to further improve the efficiency and economy of the fuel cell.

Hereinafter, the application of the sulfur component removing member of the present invention to the desulfurization apparatus of the fuel cell system will be described.

1 is a block diagram of a fuel cell system having a desulfurization apparatus of the present invention, and FIG. 2 is a schematic block diagram of an adsorption experiment apparatus for a desulfurization apparatus of the fuel cell system of the present invention.

Fuel cell system 100 is provided with a desulfurization apparatus of the present invention, as shown in Figures 1 and 2, fuel gas methane, ethane, ethylene, propane, butane, city gas, liquefied petroleum gas (LPG) or natural Desulfurization apparatus (1) for removing sulfur components contained in gas, etc., reformer (2) for reforming desulfurized fuel, heater (5) for heating reformer (2), carbon monoxide modifier for removing carbon monoxide from reformed fuel (CO transformer) (3) and carbon monoxide remover (CO remover) (4), the fuel cell system 100 including a stack (6) for converting the carbon monoxide from the removed fuel into electrical energy or thermal energy, etc. Done. In addition, there is provided an electric supply device for using the electric energy converted from the fuel supplied in this way from outside, and a heat exchanger 9 for using thermal energy. In FIG. 1, reference numeral 7 denotes a cooler, 8 denotes a coolant tank, 10 denotes a reservoir, 11 denotes an inverter, and 13 denotes an associated circuit breaker. That is, the sulfur component is removed through the desulfurization apparatus 1 and the reformer 2 and the like provided as described above, and the reformed fuel is converted into electricity or thermal energy.

Adsorption experiment apparatus 30 shown in FIG. 2 is an experimental apparatus for desulfurization experiment by the sulfur component removing member of the desulfurization apparatus 1 of the present invention. In FIG. 2, reference numeral 31 denotes an MFC, 32 denotes a 4-way valve, 33 denotes a reactor, and 34 denotes a PFD / SCD.

The standard gas of the adsorption experiment apparatus 30 is THT (24.4 ppm), TBM (13.9 ppm) / CH4 balance gas (Mixture gas), the experimental method is as follows.

1) Filling the reactor 33 with a certain amount of adsorbent (0.02 g).

2) Pretreatment while flowing nitrogen gas at 90cc / min for 30 minutes.

3) After supplying reaction gas (Flow rate = 90mL / min) using 4-way valve (32), adsorption amount was measured.

4) Measured at 10 minute intervals under the analytical conditions of Table 5.

(Gas chromatography retention time: Others: 1.3 minutes, TBM: 2.0 minutes, THT: 3.8 minutes)

5) Measure until the amount of each sulfur substance is saturated in the adsorbent.

[Table 5] Analysis condition of experiment

    Gas Chromatography Parameters: Injection port Split injection Injection temperature 200 ℃ Column Gs-gaspro Oven temperature program 245 ℃ Injection volume 5.0mL Carrier gas He (99.999%), 2.6 mL / min, 41 cm / min split ratio 50: 1 split flow 128ml / min     SCD Parameters: controller pressure 212 torr Burner temperature 800 ℃ Hydrogen flow rate 40-50sccm Oxidant flow rate 60-65sccm

Under such test conditions, the results of the experiment on the sulfur component removing member of the desulfurization apparatus 1 according to the above embodiment are shown in Table 6 below.

[Table 6] Experimental results (Calculation of adsorption amount based on 25 ℃, 1 atm)

 number  division  Adsorbent Amount (g) Adsorption amount (mgS / g adsorbent) TBM THT 0-0 AC 0.025 18.40 50.54 1-1 SAC-Ca10-I-0105 0.02 29.90 78.97 1-2 SAC-Ca9-I-0105 0.025 25.76 60.01 1-3 SAC-Ca10-I-0105 0.02 46.01 134.24 1-4 SAC-Ca11-I-0105 0.02 50.61 134.24 1-6 SAC-Ca9-I-0205 0.025 23.92 56.86 1-10 SAC-Ca9-Ⅱ-0605 0.02 27.60 75.02 1-14 SAC-Ca9-I-0305 0.02 25.30 90.81 1-17 SAC-Ca10-Ⅱ-0705 0.02 41.41 71.07 1-18 SAC-Ca9-I-0705 0.02 43.71 75.02 1-19 SAC-Co10-Ⅱ-0705 0.02 62.11 110.55 1-20 SAC-Co11-Ⅱ-0705 0.02 46.01 86.86 2-1 SAZ-Ze11-I-0105 0.02 2.30 3.95 2-5 SAZ-ze10-Ⅱ-0705 0.02 1.15 1.97

       As shown in Table 6, 1-3, 1-4, 1-19 and 1-20 are adsorbents in which Co is impregnated with activated carbon, and are effective in removing odorants such as THT and TBM.

As described above, it can be confirmed that the desulfurization apparatus 1 of the fuel cell system 100 of the present invention effectively desulfurizes sulfur components contained in the fuel. According to the desulfurization apparatus 1 of the present invention, it is possible to desulfurize at a low temperature, to be completely desulfurized at a ppb level or lower, and thus to prevent sulfur poisoning of the reforming catalyst and to shorten the starting time. Is there.

Therefore, the fuel cell system 100 of the present invention can reduce sulfur concentration by completely or almost completely removing the sulfur component contained in the fuel gas at room temperature for a long time, and thus, the stationary type using fuel such as city gas The polymer electrolyte fuel cell has a merit of being very useful for desulfurization of fuel gas for producing fuel hydrogen for fuel cells.

The present invention provided as described above can effectively desulfurize sulfur components contained in methane, ethane, ethylene, propane, butane, city gas, liquefied petroleum gas (LPG) or natural gas (LNG) at room temperature, and when reforming sulfur To reduce the risk of poisoning, and to desulfurize at room temperature, the system configuration can be stabilized, thereby reducing the start-up time, thereby making it easy to convert to electrical or thermal energy in the stack, the overall configuration of the fuel cell system There is an effect such as to be stable.

Claims (6)

In activated carbon or a mixture of activated carbon and zeolite having a micropore of at least 70%, a specific surface area of at least 1,000 m 2 / g, a hardness of at least 95%, and a particle diameter of 12x16 to 4x6 mesh, NaOH, Na ₂ CO _{3 ,} KOH, KI, I _2, CuO, Fe ₂ O _3, ZnO, Formed by attaching one selected from Cucl ₂ .2H ₂ O and FeCl ₂ , The active carbon: zeolite ratio in the mixture of the activated carbon and zeolite is 2: 8 to 8: 2, characterized in that the sulfur component removal member contained in the fuel gas. delete  The sulfur component removing member of claim 1, wherein two or more kinds of sulfur component removing members are mixed. Washing the activated carbon or zeolite with water, drying and airtight storage; Screening the activated carbon or activated carbon + zeolite with a 12 × 16 to 4 × 6 mesh particle size; NaOH, Na ₂ CO _3, KOH, KI, I _2, CuO, Fe ₂ O _3, ZnO, Preparing an aqueous solution of an impregnated substance selected from Cucl _2. 2H ₂ O and FeCl ₂ ; Mixing and stirring a mixture of activated carbon and zeolite having a ratio of the activated carbon or activated carbon: zeolite of 2: 8 to 8: 2 with the aqueous solution of the impregnated substance; And Method for producing a sulfur component removal additive comprising the step of drying the mixture of the activated carbon or activated carbon + zeolite impregnated with the impregnated material at room temperature.  A desulfurization apparatus of a fuel cell system, characterized in that the sulfur component contained in the fuel gas is desulfurized using the sulfur component removing member contained in the fuel gas according to claim 1.  The desulfurization apparatus of a fuel cell system according to claim 5, wherein the sulfur component contained in the fuel gas is desulfurized using a sulfur component removing member in which two or more types of sulfur component removing members are mixed.

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