In-Situ Oxygen Analyser for Pressurised Combustor

Abstract

Due to the increasingly stringent environmental regulations placed on the power generation industry, new methods of generating power utilising the abundant availability of coal are being developed. Included in this development is the Power Systems Development Facility's (PSDF) processes of applying pressurised combustion and gasification to increase efficiency while eliminating many of the environmentally unfriendly emissions. As with any combustion process, the measurement of oxygen in the flue gas is vitally important. The availability of the zirconium oxide in-situ oxygen analyser several years ago was a welcome change to those who had tried to maintain a real-time, accurate flue gas oxygen measurement. The zirconium oxide in-situ oxygen analyser is now the chosen method for measuring flue gas oxygen at virtually all power boiler outlets. During the detail design stages of the PSDF in the early 1990s, an in-situ oxygen analyser could not be found that would operate at the required combustor pressures of 150–300 psig. Recently, following numerous inquiries of various vendors around the world, a vendor was found who has developed a sensor that will act as a pressure boundary to 170 psig and an electronics unit that will accept a 4–20 mA input from a pressure transmitter for oxygen partial pressure compensation. This analyser has been successfully tested in the combustor outlet of the PSDF at a process pressure of 130 psig. The performance of the analyser is presented.