Reformers membrane

Pd membrane tube First jacket SS tube Second jacket SS tube 

Kikuchi [111] described a natural gas MR, which had been developed and operated by Tokyo Gas and Mitsubishi Heavy Industries to supply PEM fuel cells with hydrogen. It was composed of a central burner surrounded by a catalyst bed filled with commercial nickel catalyst. Into the catalyst bed 24 supported palladium membrane tubes were inserted. The membranes had been prepared by electroless plating and were 20 pm thick. Steam was used as sweep gas for the permeate. The reactor carried 14.5 kg catalyst. It was operated at 6.2 bar pressure, S/C ratio of 2.4, and 550°C reaction temperature. The conversion of the natural gas was close to 100%, wdiile the equilibrium conversion was only 30% under the operating conditions. The retentate composition was 6 vol.% hydrogen, 1 vol.% carbon monoxide, 91 vol.% carbon dioxide, and 2 vol.% methane. 

Basile and Putzuro [112] prepared a palladium membrane by electroless plating palladium with a thickness of 70 pm onto tita-nia tubes and incorporated them into MRs for the partial oxidation of methane. The H2/N2 separation factor of these membranes was still quite low (between 3 and 4.7), while carbon deposition on the membrane was negligible for operation up to 400° C. 

Kunmgot et al. [ 114] developed a silica membrane and incorporated it into a catalytic MR for the partial oxidation of methane. Rhodium catalyst on y-alumina carrier containing 1 wt.% 

An electrochemical MR was presented by Yamaguchi et al. [119]. Proton conducting ceramic electrolyte and a 

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Yasuda, I. et al., Development of membrane reformer for highly-efficient hydrogen production from natural gas, Proceeding of XV World Hydrogen Energy Conference, Yokohama, Japan, 2004. 

Steam methane reforming with membrane reformer/WGS reactor for hydrogen production. 

Yasuda, I., T. Tsuneki, and S. Shiraski, Development of Membrane Reformer System for Highly-Efficient Hydrogen Production from Natural Gas, World Conference on Wind Energy, Renewable Energy, Fuel Cell (WCWRF 2005), Hamamatsu, Japan, June 2005. 

Hori, M. (2007a), Electricity Generation in Fuel Cell Using Nuclear-fossil Synergistic Hydrogen -Evaluation of a System with Sodium Reactor Heated Natural Gas Membrane Reformer and Alkaline Fuel Cell , 2007 Fall Meeting of Atomic Energy Society of Japan, Japan, September (in Japanese). 

The product gas leaves the secondary reformer at a temperature of 885°C and is heat-exchanged in the primary membrane reformer. After that, the product gas leaving the gas-heated reformer is utilised for preheating of the natural gas feed, heating of circulating water in the saturator loop and generation of LP steam at 3 bar. Finally, after a temperature decrease to 265°C the gas is fed to a shift converter, after which again methanation takes place and removal of CO2 and traces of water. 

Yasuda, I., Shirasaki, Y., Tsuneki, T., Asakura, T., Kataoka, A., Shinkai, H., Yamaguchi, R. (2004). Development of membrane reformer for high-efficient hydrogen production from natural gas. In "15 World Hydrogen Energy Conference, Yokohama 2004". Hydrogen Energy Systems Soc. of Japan (CDROM). 

Hydrogen is able to permeate selectively through palladium or palladium alloy membranes. This has led to the demonstration of membrane reformers in the labora-... 

Membrane reforming of synthetic natural gas from coal (M. Hori - NSA, Ref 13)... 

In the case of recirculation-type membrane reformer, efficiency of reactor heat utilisation = 60%, yield of hydrogen from methane = 95%... 

As for the nuclear-heated steam reforming of synthetic crude, the medium temperature recirculation-type membrane reforming process (Ref. 10) can be applied, where either SFR (sodium fast reactor) or SCWR (supercritical water reactor) could be adopted as medium-temperature heat source. 

M. Tashimo, et. al., Advanced Design of Fast Reactor - Membrane Reformer , Proceedings of OECD/NEA Second Information Exchange Meeting on Nuclear Production of Hydrogen, Argonne USA, 2-3, October 2003, p.267 (2003). 

A concept for nuclear production of hydrogen, FR-MR , which combines sodium cooled fast reactors (SFR) with the membrane reformer technology, has been studied jointly by MHI, ARTEC, TGC and NSA[15]. 

TGC has demonstrated the operation of membrane reformer at a hydrogen fueling station for FCV in downtown Tokyo in 2004-2005. The system performance, efficiency and long-term durability/reliability were confirmed by producing >99.99% hydrogen at 40 Nm /h for more than 3 000 hours with hydrogen production efficiency of about 80% (HHV). 

In the conceptual design, the nuclear plant is a type of SFR, mixed oxide fuel, sodium cooled with power output of 240 MWt for producing 200 000 Nm /h. The schematic diagram of nuclear-heated recirculation-type membrane reformer is shown in Figure 15. The hydrogen production cost of this process is assessed to be competitive with those of the conventional, natural gas burning, steam methane reformer plants. 

Figure 15. Concept of Fast Reactor Membrane Reformer...

Successful applications of dynamic membranes in a number of industrial separation processes, membrane stability at high temperature and over a broad pH range, and membrane reformation capability on durable substrates have attracted a significant research and development effort. Much of the research has been directed toward... 

Membrane reformers take advantage of a useful feature of hydrogen, namely its ability to selectively permeate through Pd or Pd alloy membranes. As has been shown on a laboratory scale, the hydrogen is relatively clean and its continuous removal increases the methane conversion level [21]. 

P. Ferreira-Aparicio, M. Benito, K. Koua-chi, S. Menad, Catalysis in membrane reformers A high-performance catalytic system for hydrogen production from methane,/. Catal. 2005, 231, 331-343. 

S. L. Jorgensen, Membrane reforming for hydrogen, Catal. Today 199S. 46(2-3), 193-201. 

Dijkstra et al. [56] compared membrane WGS reaction with membrane reforming in the natural gas combined cycles with CO2 capture. Their simulation results indicate that membrane WGS reaction suits well for CO2 capture compared to the membrane reforming. The lower hydrogen partial pressure in a membrane reformer compared to membrane WGS causes high investment... 

Simakov DSA and Sheintuch M. Experimental optimization of an autonomous scaled-down methane membrane reformer for hydrogen generation. Ind. Eng. Chem. Res. 2010 49 1123-1129. 

A possible approach Natural gas can be converted at a high temperature into hydrogen, CO, C02 (syngas) in a steam reformer or partial-oxidation reactor, or autothermal reformer which is a combination of the first two. Most of the CO in the syngas is typically converted into carbon dioxide at a lower temperature in a water-gas shift reactor. The remaining small amount of CO must be removed to below 10 ppm level. This can be done using adsorption, or membrane separation, or catalytic preferential oxidation (at about 90°C with an air stream), or other practical means. Also, there are designs with membrane reformers in the literature. 

Chen Z, Yan Y, Elnashaie SSEH (2(X)3) Modeling and optimization of a novel membrane reformer for higher hydrocarbons. AIChE J 49 1250-1265... 

Chen Z, Yan Y, Elnashaie SSEH (2003) Novel dreulating fast Iluidized-bed membrane reformer for efficient production of hydrogen fiom steam tefOTming of methane. Chem Eng Sci 58 4335-4349... 

Simakov DSA, Sheintuch M (2008) Design of a thermally balanced membrane reformer for hydrogen production. AIChE J 54 2735-2750... 

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