OPERATING EXPERIENCE AND PERFORMANCE CHARACTERISTICS OF A GAS-OXY COMBUSTION TECHNOLOGY AT TOTAL’S CARBON CAPTURE AND STORAGE DEMONSTRATION PLANT

摘要

In January 2010, TOTAL began operating Europe’s first fully integrated carbon capture and storage (CCS) demonstration facility, in Lacq, near Pau in southwestern France. The pilot plant uses 99% pure oxygen, produced by an air separation unit (ASU), which is substituted for air to combust natural gas in a 30MWth industrial boiler. The original air combustion boiler had been refurbished and modified suitable for oxy combustion. Flue gas leaving the boiler consisting primarily of water vapor and carbon dioxide (CO2) gas is further conditioned in a compression and purification unit (CPU). Dried carbon dioxide gas travels through a 30 kilometer pipeline to be injected into a depleted natural gas reservoir, 4500 meters underground in a porous sedimentary rock formation extending over two square kilometers. In December 2011, in collaboration with Babcock & Wilcox Canada (BWC) and Air Liquide of France, Total embarked on a comprehensive testing campaign at Lacq to gain in-depth knowledge of oxy-combustion technology. The following observations were made comparing oxy combustion to air combustion: The boiler operated with much higher efficiencies, as well as lower furnace exit gas temperatures (FEGT) in oxy mode. Incident heat fluxes increased in oxy mode as measured at various locations in the furnace for the same load cases. Percentages of heat absorption between the furnace and convection pass including superheater, steam generating banks, and economizer were similar for both air- and oxy-combustion modes. Nitrogen oxides (NOx) emissions trended lower as the load increased in oxy-combustion mode.