Verfahren zur Erzeugung eines wasserstoffreichen Produktgases aus Biomasse in einem Wirbelschichtvergaser

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• Publisher: Cuvillier Verlag
• Year: 2008
• Print ISBN: 9783867278430
• eBook ISBN: 9783736928435
• Edition: 1

The discussion about the future energy supply for mankind is based on the factthat fossil energy resources are limited. It is also based on the fact, that theemissions from the use of these fossil fuels has caused an increase in theconcentration of CO2 in the atmosphere over the last number of years.There are several ways to reduce CO2 emissions. One is to increase theefficiency of power plants to reduce their fuel needs. Another way – particularlyfor fossil fuel - is to capture CO2 from the flue gases. A third way is to usebiomasses as fuel. As a first approach, one can say that biomass takes thatmuch CO2 out of the atmosphere during growth as it will emit during combustion.This thesis is about a process which produces a hydrogen-rich gas frombiomass. This gas can further be used both as a base for further synthesis andfor electricity production.In the process described, biomass is gasified under steam atmosphere at atemperature between 450°C and 750°C. The reactor is a circulating fluidisedbed. Instead of inert bed material, which is normally used, lime is used. At thistemperature window lime reacts with the CO2 to produce limestone. CO2 istaken from the gas phase to solid phase and is not present in product gas anymore. Additionally the equilibrium of watergas-shift-reaction (CO and H2O reactto H2 and CO2) is pushed to the H2 side due to the lack of CO2 in the productgas. The absorption of the CO2 by the lime enhances the hydrogen production;this process is called Absorption Enhanced Reforming (AER).