Clean fossil fuel heat and power plants - General information

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Pre combustion

An example of a pre combustion process is the Integrated Gasification Combined Cycle (IGCC). Figure 1 illustrates this process where the carbon in the fuel is extracted before (pre) the combustion takes place. Coal is converted into H₂ and CO₂ with gasification and shift conversion. The CO₂ is removed from the gasification- and shift products by, for example, a chemical solvent. The remaining fuel gas, which contains mainly H₂, is fired in a combined power cycle.

Figure 1: Integrated Gasification Combined Cycle (IGCC)

An example of the CO₂ separation unit is illustrated in Figure 2. The amine Methyl-diethanolamine (MDEA) is used for a pre combustion CO₂ separation.

Figure 2: CO₂ Separation Unit

The CO₂ in the inlet gas is attached to the amine solvent in the absorber tower under relative high pressure and low temperature, and the CO₂ is released from the amine solvent in the stripper tower under relative low pressure and high temperature. In the absorption process it is normal to absorb between 80 and 95 % of the CO₂ in the inlet gas stream.

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