Washington, D.C. –The Office of Fossil Energy's National Energy Technology Laboratory (NETL) has partnered with Air Products and Chemicals Inc. of Allentown, Penn. to develop the Ion Transport Membrane (ITM) Oxygen, a revolutionary new oxygen-production technology that requires less energy and offers lower capital costs than conventional technologies. ITM Oxygen will enhance the performance of integrated gasification combined cycle (IGCC) power plants, as well as other gasification-based processes. The technology will also enhance the economics of oxy-fired combustion technologies, making it an attractive option for the capture of carbon dioxide from existing coal-fired power plants.
Since NETL and Air Products teamed up in 1998 to develop the membrane material and process, they have made steady progress toward its commercialization. The technology is now being validated in a 5 tons-per-day prototype facility and producing high purity oxygen at record production flux under commercially relevant conditions. The tests are confirming earlier predictive studies as to expected economic benefits of ITM Oxygen, and the technology is being scaled up to 150 tons per day. The 12-year project has also created 160 new jobs.
Researchers view ITM Oxygen as a transformative technology with potential to increase the cost effectiveness of next-generation plants. Other oxygen-intensive industries—such as steel, glass, non-ferrous metallurgy, refineries, and pulp and paper—could also realize cost, environmental, and productivity benefits as a result of the technology.
The ITM Oxygen technology is a radically different approach to producing low-cost, high-temperature, high-quality tonnage oxygen. Existing technology is energy intensive and requires air to be cooled to approximately -280 degrees Fahrenheit, the temperature at which air becomes a liquid and oxygen can be separated. In contrast, the electrochemical properties of the ITM Oxygen make it possible to selectively separate oxygen from a stream of air at high temperature and pressure.
In the ITM Oxygen process, oxygen in high-temperature, high-pressure air is ionized at the surface of the ceramic membrane and transported through the membrane via a pressure gradient. The oxygen ions recombine as pure oxygen on the permeate or low-pressure side and leave a stream of hot, compressed, oxygen-depleted air on the feed or non-permeate side. The energy of the hot non-permeate stream is recovered through conversion to electrical energy and steam. The overall process enables cost-effective co-production of power and high purity oxygen that is synergistic with modern power production applications.
As part of the on-going project, a subscale engineering prototype facility was designed and built to test multiple membrane modules under commercially relevant operating conditions. The prototype facility, which was designed to produce up to 5 tons of oxygen per day, was successfully commissioned and is now fulfilling test requirements using an array of commercial-scale ITM modules operating simultaneously.
Twelve test runs over a range of driving forces have been completed to date. During more than 9,000 hours of operation, commercial flux targets have been achieved or surpassed and product purity has exceeded 99 percent. Additional tests, involving the cycling of the membranes through a range of pressures and temperatures, are now underway to assess the robustness of the membranes under startup and shutdown conditions and potential process upsets.
Testing in the prototype facility is providing engineering data to support the design of a 150 tons/day test facility that will co-produce oxygen and power. The larger facility is expected to begin commissioning in late 2010.