Abstract: A method of producing a gaseous product, for instance gaseous oxygen in accordance with a cyclical demand pattern having high and low periods of demand. During periods of high demand, liquid is vaporized against condensing air which is in turn stored. During low demand periods, product is accumulated and previously stored liquid air is introduced into the column. During both high and low periods of demand liquid product is drawn to reduce the percentage variance in the required flow rate to the booster compressor used in producing the air to be liquefied. Preferably, during periods of high demand, a turbine used in generating refrigeration can be turned down to increase the amount of air available for condensation and with a reduction in production of liquid product.

Abstract: A method and apparatus for making gaseous oxygen at a delivery pressure in a single column oxygen generator. In accordance with the method and apparatus, a column bottoms stream composed of the product is pumped to the delivery pressure and then vaporized. A liquid coolant stream used in condensing reflux is recompressed by a recycle compressor and then recycled back into the bottom of the column. Such recycled stream has a higher nitrogen content than the column bottoms. Part of the nitrogen tower overhead, not used in forming the reflux, is turbo-expanded by a turbo-expander coupled to the recycle compressor.