Purified O2 streams are utilized in many sectors of the industrial economy, including combustion, steel production, glass and cement production, petrochemical processing, metallurgy, pulp and paper production, and biochemical processing and waste treatment. For example, purified O2 streams are used in oxy-fuel combustion to improve the heat transfer associated with stationary energy processes. In 2003, total shipments of purified O2 amounted to nearly 26 million tons, a value of approximately $1 billion, requiring over five million MWh of energy to produce.
However, pure oxygen (O2) generation's overall penetration into industrial and power markets is constrained by the high cost of existing air separation technologies. Cryogenic air separation is the most widely used technology for generating large flows of oxygen but is a complex and expensive technology. Currently, for a 600 MWe (gross) oxy-fuel power plant using cryogenic air separation, 100 MWe will be consumed by air-separation, resulting in an efficiency decrease of 10 percentage points. Pressure swing adsorption (PSA) is a competing technology that uses separations materials such as activated carbon, zeolites and polymer membranes. Current PSA technology is expensive and limited to moderate purity O2 applications because of limitations of existing separations materials. For current zeolite-based PSA processes, capital costs (primarily adsorption vessels and compressors) and operating costs (primarily energy costs) each represent approximately 50% of the total cost of air separation. There have been no significant breakthroughs in air separation technologies for several decades.
Technology is needed to reduce the expense and increase purity in O2 separation technology.