Adding gas from biomass to the gas grid - SGC

fixed bed gasification: LURGI-MPGProcess name: Lurgi Multi Purpose GasificationManufacturerLurgiOrigin:GermanyCapacity:typically 150,000 tons/yearDescription:fixed bed gasifier• pressure 1200 - 1450 °C• temperature 30 - 75 bar• reactants oxygen and steamStatus:demonstrated for coal and refinery residuesEfficiencynot reportedThe MPG gasification is carried out at temperatures of 1200 - 1450 °C and pressures of between 30 and 75bar. The feedstock enters the refractory-lined reactor through a top-mounted, specially designed burner.Oxygen is mixed with steam as a moderator prior to being fed to the burner.Reactor configurationsSoot and metals ashes are removed from the raw syngas by means of wash water. The resulting soot slurryis routed to slurry treatment. After separation of the ash-soot, the greater part of this water is recycled asreturn water to the washing units. The excess water is routed to waste water treatment. The gasification unittypically consists of three main components: the reactor, the syngas cooling section and the carbonhandling system complemented by the Metals Ash Recovery System (MARS).To provide maximum feedstock and product flexibility, Lurgi offers two variants for the syngas coolingsection, the boiler and the quench configuration. The boiler configuration is suitable for feedstocks with lowconcentrations of contaminants, generates considerable amounts of high-pressure steam and offers highestenergy efficiency. The quench configuration is required when the feedstock contamination is above theboiler's. This configuration allows feedstocks like coke/coal slurries and wastes, offers highest flexibility atlowest investment cost.Quench configurationIn the quench configuration, the hot raw gas from the reactor is shock-cooled, ‘quenched’, with water whichis injected into a quench nozzle. The gas is cooled almost instantaneously to steam saturation temperatureand leaves the quench separator sideways. When processing high-ash feedstocks, the molten slag formingflows down the reactor wall into the quench nozzle where it is blast-cooled to form glassy spheres which arewithdrawn via the slag hopper. This glassy slag carries most of the heavy metals and water-insolubles. It isnon-leachable and can be easily disposed of (e.g. in road construction).The remaining ash and soot particles are removed from the gas in the venturi scrubber downstream of thequench. Further cooling occurs in a medium-pressure steam boiler, which generates steam at 15 to 30 bars.page: 125