Hydrogen in syngas

De Falco M, laquaniello G, Cucchiella B, Marrelli L (2009) Reformer and membrane modules plant to optimize natural gas conversion to hydrogen. In Syngas production methods, post treatment and economics. Nova Science Publishers Inc. New York. ISBN 978-1-60741-841-2... 

Fig. 8.13 shows Cycle B2, a development of Lloyd s simple steam/TCR cycle for CO2 removal, as proposed by Lozza and Chiesa [7J. However, this is a CCGT plant in which the syngas produced by the steam reformer is cooled and then fed to a chemical absorption process. This enables both water and CO2 in the syngas to be removed and a hydrogen rich syngas to be fed to the combustion chamber. 

Catalytic upgrading of the hydrogen-rich syngas (tar and hydrocarbon conversion, possibly in combination with filtration, also water gas shift catalyst use and... 

Fischer-Tropsch synthesis requires a stochiometric H2 CO ratio of 2.1 1. If coal or biomass are used as feedstock, the raw syngas contains much less hydrogen than needed. Hence, CO is reacted with water to form C02 and hydrogen in the shift reactor. As the C02 cannot be used in the Fischer-Tropsch synthesis, part of the carbon for fuel production is lost in this process. If external hydrogen is added to increase the H2 CO ratio, the carbon of the coal or biomass is more effectively used and the hydrocarbon product yield is improved. 

R D for hydrogen production for its utilization in fuel cells, based in Syngas obtained through gasification process. 

Steam reformers are used industrially to produce syngas, i.e., synthetic gas formed of CO, CO2, 11-2, and/or hydrogen. In this section we present models for both top-fired and side-fired industrial steam reformers by using three different diffusion-reaction models for the catalyst pellet. The dusty gas model gives the simplest effective method to describe the intermediate region of diffusion and reaction in the reformer, where all modes of transport are significant. This model can predict the behavior of the catalyst pellet in difficult circumstances. Two simplified models (A) and (B) can also be used, as well as a kinetic model for both steam reforming and methanation. The results obtained for these models are compared with industrial results near the thermodynamic equilibrium as well as far from it. 

The syngas in the C02 Absorber overhead stream is water-washed and fed to a MEDAL membrane unit. The membrane feed gas is sent to a coalescing filter to remove liquids and is preheated before is enters the permeator. In the permeator, syngas is separated into a hydrogen-rich permeate and the syngas product. The operation of the membrane unit is very simple. The driving force for separation is the difference in partial pressure between the hydrogen in the feed gas and that of the permeate. 

B. J. Cromarty, et ah, Emerging Trends in Syngas and Hydrogen. Presented at CatCon2000, 12-13 June, 2000, Houston, TX, USA. 

The ratio of CO to H2 in syngas can be controlled by the water-gas shift reaction (WGSR, Equation 7) and it is possible to make either hydrogen or carbon monoxide, or any ratio of the two, by suitable adjustment of conditions. 

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