An oxygen-rich gas stream, containing 90-92% oxygen by weight, is needed to combust biomass in the gasifier. Oxygen-rich gas from the oxygen receiver at the air separation plant is pressurized by the oxygen booster compressor to about 180 PSIG and is stored in a vendor supplied surge tank. Oxygen from the surge tank is mixed with medium pressure superheated steam prior to introduction to the gasifier. The oxygen surge tank is part of the owner’s scope of supply.