Catalyst and method for producing synthesis gas or enriched hydrogen gas mixture of water-alcohol mixtures

 

(57) Abstract:

The invention relates to a catalyst and method of conducting the reaction of steam reforming of ethanol. The invention solves the problem of increasing the efficiency of the process steam reforming of ethanol by increasing feedstock through the use of water-ethanol mixtures containing methanol and prevent deactivation of the catalyst and formation of side products. The problem is solved by carrying out the reaction of steam reforming of alcohols in the synthesis gas or enriched hydrogen gas mixture in the reactor with two fixed layers of catalysts. The layers consist of different catalysts and operate at different temperatures. The catalyst for the first layer as the active component contains metals IB group of the Periodic system and of noble metals deposited on a graphite-like carbon carrier in an amount not less than 0.05 wt.%. As the catalyst of the second layer using Nickel-containing catalyst, as alcohol use ethanol or metasomatically mixture. The proposed method of processing ethanol, including ethanol, synthesis gas or enriched hydrogen gas mixture allows the use of vodnoy widest possible variation of their chemical composition. The proposed method allows to avoid the formation of by-products, reducing the output of the synthesis gas or enriched hydrogen gas mixture. 2 S. and 9 C.p. f-crystals, 4 PL.

The invention relates to a catalyst and a catalytic method implementing the reaction of steam reforming of ethanol in order to obtain a synthesis gas or enriched hydrogen gas mixture, which can be used in various industries, including hydrogen energy, for example, as fuel for fuel cells.

It is known that ethanol is widely available renewable raw materials, industrial production technology of which is well developed, for example, the biochemical processing of sugar cane, crops, or timber. The bioethanol is an aqueous solution containing about 12 wt.% of ethanol. Especially attractive were the processes that allow processing of bioethanol without distillation. This process is steam reforming of ethanol to produce synthesis gas or enriched hydrogen gas mixtures.

It is known that hydrogen steam reforming ethanol confirmed ta, D. Geana, Int. J. Energy, A thermodynamic analysis of hydrogen production by steam reforming of ethanol via response reactions 25(2000)31), with the main hydrogen-containing product of steam reforming of ethanol at moderate temperatures is methane, whereas at high temperatures and large molar relationship of water/ethanol is produced mainly hydrogen-containing mixture.

There is a method of steam reforming of ethanol on cobalt containing catalysts with the use of oxide and carbon carriers (F. Haga, T. Nakajama, H. Miya, S. Mishima, Catal. Lett. Catalytic properties of supported cobalt catalysts for steam reforming of ethanol, 48(1997)223). The disadvantage of this method is the formation of by-products such as methane, methanol, ethylene, acetaldehyde, diethyl ether. It is well known that in the presence of ethylene formation of carbon on the catalyst is greatly enhanced (J. R. Rosrup-Nielsen, Catalytic steam reforming, Catalysis Science and Technology, Eds, J. R. Anderson and M. Boudart, v.5, Ch.1, Springer-Verlag, Berlin, 1984).

A method of obtaining an enriched hydrogen gas mixture of steam conversion of ethanol promoted potassium Ni - and Cu-containing catalysts deposited on Al2O3(F. J. Marino, E. G. Cerrela, S. Dunalde at al., J. Hydrogen Energy, Hydrogen from steam reforming of ethanol. Characterization and performance of cupper-nickel supported catalysts, 23(1998)1095). Main under SCA conversion of ethanol, the formation of by-products, such as methane, acetaldehyde, diethyl ether). The disadvantage is the need for more complex catalytic system (introduction potassium-containing promoter) to reduce the formation of side products.

In addition, the known method (prototype), according to which the process of obtaining hydrogen is carried out in a reactor with two fixed layers of the catalyst using the catalyst Cu/SiO2in the first stage (S. Freni, N. Mondello, S. Cavallaro, G. Cacciola, V. N. Parmon, V. A. Sobyanin. React. Kinet. Catal. Lett., Hydrogen production by steam reforming of ethanol two step process, 71(2000)143). At this stage of ethanol produces acetaldehyde, a steam conversion of which the second stage catalyst Ni/MgO leads to the formation of hydrogen-rich gas mixture. The disadvantage of this method is the rapid deactivation of the catalyst Cu/SiO2.

Task to be solved by the present invention is directed, is to increase the efficiency of the process of steam reforming of ethanol with the aim of obtaining synthesis gas or hydrogen-rich gas mixture by expanding the types of raw materials due to the use of water-ethanol mixtures containing methanol and prevent deactivation produce the conversion of alcohols into synthesis gas enriched with hydrogen gas mixture in the reactor with two fixed layers of catalysts. The layers consist of different catalysts and operate at different temperatures. The catalyst for the first layer as an active ingredient contains a metal IB group of the Periodic system, selected from the group consisting of copper, silver, gold, or precious metal selected from the group consisting of platinum, palladium, ruthenium, rhodium, iridium deposited on a graphite-like carbon carrier in the amount of not less than 0.05 wt.%.

Graphite-like carbon material is a three-dimensional carbon matrix with the pore volume of 0.2-1.7 cm3/g formed by the belt layers of carbon with a thickness 100-10000 and with a radius of curvature of 100-10000 having a true density equal to 1.80 to 2.10 g/cm3, x-ray density 2.112-2.236 g/cm3and porous structure with a pore distribution with a maximum in the range 200-2000 or biporous structure with pore distribution with an additional maximum in the range of 40-200 .

As the catalyst of the second layer using Nickel-containing catalyst, as alcohol use ethanol or methanol-ethanol mixture.

The process in the first layer is carried out at a temperature not lower than 200oC, the process in the second layer is carried out at a temperature which MESI, having a concentration of from 1 to 50 vol.%.

Depending on the applied first layer of catalyst in the steam reforming process can be done in two ways.

(1) Ethanol or ethanol-water mixture on the first layer of catalyst (catalysts: platinum, palladium, ruthenium, rhodium, iridium) is transformed into a gaseous mixture of CO, CH4and H2reaction:

(2) C2H5OH=CH4+CO+H2, (1)

then on the second layer of the catalyst is converted into synthesis gas enriched with hydrogen gas mixture according to the reaction:

CH4+ 3H2O = CO2+ 5H2(2)

H2+ CO2= CO + H2O (3)

(2) Ethanol or ethanol-water mixture on the first layer of catalyst (catalysts: copper, silver) is transformed into acetaldehyde and hydrogen by the reaction:

C2H5OH = CH3CHO + H2(4)

and then a second layer of the catalyst mixture of acetaldehyde and hydrogen is converted into synthesis gas or enriched hydrogen gas mixture according to the reaction:

CH3CHO + 3H2O = 2CO2+ 5H2(5)

H2+ CO2= CO + H2O (6)

The distinguishing feature is the use in the first phase of catalysts on the basis of the elements of the IB group Pay material, representing three-dimensional carbon matrix with the pore volume of 0.2 - 1.7 cm3/g formed by the belt layers of carbon with a thickness 100-10000 and with a radius of curvature of 100-10000 having a true density equal to 1.80 to 2.10 g/cm3, x-ray density 2.112-2.236 g/cm3and porous structure with a pore distribution with a maximum in the range 200-2000 or biporous structure with pore distribution with an additional maximum in the range of 40-200 (US Patent 4978649, C 01 B 31/10, 1990; RF Patent N 1706690, C 01 B 31/10, 1992).

The steam reforming reaction of ethanol is carried out in a flow reactor with two fixed layers of the catalyst. The reactor was a quartz tube with an inner diameter of 8 mm Layers consisted of 0.5-1 g of catalyst was mixed with 5 g of inert material SiC. As catalysts for the first stage is used platinum, palladium, ruthenium, copper on graphite-like carbon media. As catalysts for the second stage using known industrial Nickel-containing catalysts for methane conversion GIAP-16 (Handbook of apothica // ed Melnikova E. J. M.: Chemistry, 1986, 512 S.). Layers of catalysts fixed quartz fiber (quartz wool). The volumetric rate varies in the range of 1000-100000 h-1e pressures of 1-10 ATM. The reaction gas mixture has a composition of from 1 to about 50. % C2H5OH in H2O. All presents data obtained after the catalysts for 25 hours.

The invention is illustrated by the following examples.

Example 1.

Steam reforming of ethanol into hydrogen-rich mixture is carried out at atmospheric pressure in a flow reactor with two fixed layers of the catalyst. The process in the first layer is carried out on the catalyst 1 wt.% Pd/C at a temperature of 330oC, flow rate of 2200 h-1and atmospheric pressure. The reaction mixture consists of 11,2% vol. C2H5OH + 88.8% vol. H2O. the Second layer includes an industrial catalyst GIAP-16 in number 1, the results are shown in Table 1.

Example 2.

Steam reforming of ethanol into hydrogen-rich mixture is carried out at atmospheric pressure in a flow reactor with two fixed layers of the catalyst. The first layer contains the catalyst 15 wt.% Cu/C and the process it is carried out at a temperature of 340oC, flow rate 100000 h-1and atmospheric pressure. The reaction mixture consists of 15,3% vol. C2H5OH + 84.7% vol. H2O. the Second layer contains measures 3.

Steam reforming ethanol-methanol mixture in a hydrogen-rich mixture is carried out at atmospheric pressure in a flow reactor with two fixed layers of the catalyst. The reaction gas mixture consists of 10 vol.%2H5OH + about 10. % CH3OH + 80% vol. H2O. the First layer contains a catalyst 1 wt. % Pd/C and carry out the process of steam reforming at a temperature of 330oC and space velocity of the mixture 2200 h-1. The second layer includes an industrial catalyst GIAP-16 in number g the results are shown in Table 3.

Example 4 (prototype).

Steam reforming of ethanol into hydrogen-rich mixture is carried out in a flow reactor with two fixed layers of the catalyst. The process in the first layer is performed on the catalyst 15% Cu/SiO2when flow rate 109000 h-1. The reaction mixture consists of about 9.4. % C2H5OH + 76.8% vol. H2O+13.8% vol. N2. Temperature 375oC.

The second layer contains a catalyst Ni/MgO in the amount of 0.12, the results are shown in Table 4.

These examples demonstrate the high activity, selectivity and stability of the catalysts in the process of the method is a method of processing ethanol, including bioethanol, synthesis gas or enriched hydrogen gas mixture allows the use of hydroalcoholic mixture without distillation, which has important technological value. The proposed catalysts offer the possibility of varying their chemical composition. The proposed method and the use of the proposed catalysts allows to avoid the formation of by-products, reducing the output of the synthesis gas or enriched hydrogen gas mixture.

1. The catalyst for the first layer process for production of synthesis gas or enriched hydrogen gas mixture of steam conversion of alcohols containing an active component on the carrier, characterized in that the active ingredient it contains 1B metal group of the Periodic system or a noble metal deposited on a graphite-like carbon media.

2. The catalyst p. 1, characterized in that the graphite-like carbon material is a three-dimensional carbon matrix with the pore volume of 0.2-1.7 cm3/g formed by the belt layers of carbon with a thickness 100-10000 and with a radius of curvature of 100-10000 having a true density equal 1,80-2,10 g/cm3, x-ray density 2,112-2,236 g/cm3and ponies then, with an additional maximum in the range of 40-200

3. The catalyst according to any one of paragraphs.1 and 2, characterized in that it contains a metal selected from the group consisting of copper, silver, gold.

4. The catalyst according to any one of paragraphs.1 and 2, characterized in that it contains a metal selected from the group consisting of platinum, palladium, ruthenium, rhodium, iridium.

5. The catalyst according to any one of paragraphs.1-4, characterized in that it contains an active ingredient in an amount of not less than 0.05 wt.%.

6. Method for production of synthesis gas or enriched hydrogen gas mixture of steam conversion of alcohols in the reactor with two fixed layers of the catalyst, where the catalyst of the second layer using Nickel-containing catalyst, wherein the catalyst of the first layer using the catalyst according to any one of paragraphs.1-5.

7. The method according to p. 6, characterized in that as alcohol use ethanol or metasomatically mixture.

8. The method according to any of paragraphs.6 and 7, characterized in that the process in the first layer is carried out at a temperature not lower than 200oC.

9. The method according to any of paragraphs.6-8, characterized in that the process in the second layer is carried out at a temperature not lower than 500oC.

10. The method according to any of paragraphs.6-9, trichosis fact, what alcohol use in a water-alcohol mixture having a concentration of 1-50 vol.%.

 

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