Burning clean fuel gas improves energetic efficiency

One the most critical problems faced by refineries nowadays is the continuous increasing of legislation urging emissions reductions specifically SO2, NOx, and particles. Therefore there is a substantial need for refineries to burn fuel gas instead of fuel oil and avoiding, if possible, the use of imported natural gas. The refinery case study presents a substantial excess of fuel gas resulting from the production of hydrogen to obtain clean flues with low sulphurs. The aim of this paper is to optimize the use of the hydrogen excess with the implementation of a gas turbine with heat recovery with a feed near 28-31% of hydrogen. The cogeneration system was modelled by GateCycle 5.34.0.r. and the results obtained for the simulation were considered optimistic. Considering a production of 13 MW of electrical power the overall efficiency reached a value of 76% and 22 t/h of vapour (17 MW) from a feed of 3 t/h of fuel gas (39 MW). These results allow a higher electrical power production and a consequent reduction in the emissions of SO2 and CO2.