Adding gas from biomass to the gas grid - SGC

Aspect Unit ValueManure M 3 /day 6Biogas production, 60% methane atM 3 /day 10017m 3 biogas/m 3 biomassInvestmentsPlant investment incl. powerK€ 100 - 300generationPrice of gas C€/m 3biogasn.a.Table 4: ‘Farm Plant’ characteristicsBiogas from farms is always used locally for heat and power production, no examples are knownwhere it has been upgraded and added to the gas grid.Sewage plantsNo consistent figures are available.LandfillNo consistent figures are available. The high content of nitrogen makes the gas unsuitable forupgrading and injection into a high calorific natural gas grid.3.2 SYNGAS FROM BIOMASS PYROLYSIS AND GASIFICATION3.2.1 General aspects of thermal biomass gasificationGasification technology for syngas production from biomassThe technology for the thermal gasification of biomass is mainly derived from the gasification ofcoal. There is a tremendous worldwide experience basis in the gasification of coal. The coalgasification is a mature technology able to fulfil any rational commercial requirements. Thisexperience started already in the 1850’s when the first coal gas pipelines came on stream. Currentcoal gasification technology has three branches to be distinguished by their reactor characteristics.These three branches are fixed bed, fluidised bed and entrained flow gasifiers.In the fixed bed the biomass is embedded in a flow of the reactant. During the gasification theremaining ashes are removed and new biomass is added. This causes some movement in thebiomass. In some gasifiers rotating the gasifier enhances this movement by some rotatingmovement in the reacting chamber. This movement is to remove the ashes and to enhance theinteraction of the reactant gases with the biomass.Essentially this reactor shows plug flow and has an essentially high conversion efficiency.page: 20