Pursuing the pre-combustion route in oil refineries -The impact on fired heaters

Industrial fired heaters and boilers are process units that use hot gases and radiation from combustion to provide heat for crude oil, processing fluids, steam, etc. In oil refineries, the fuel feed is either low quality heavy oil or refinery gas, both which are by-products from the refinery. Fired heaters in oil refineries typically contribute to over 65% of the CO₂ emissions in these plants, and it is expected that the incentives for reducing these emissions will increase in the coming years. The “pre-combustion” route for carbon capture and storage (CCS) from refineries implies retrofitting existing gas- or oil fired heaters with burners capable of operating with a high H₂-content gas. As a first approach towards a retrofit solution for refinery heaters, the present work focus on the radiant section of a typical fired heater configuration by investigating the effect of substituting refinery gas in a typical burner configuration with a hydrogen rich gas. A Computational Fluid Dynamics (CFD) model is setup as a three-dimensional typical fired heater geometry. The CFD results are used to evaluate the effect of replacing refinery fuel gas with hydrogen, i.e., the heat distribution in the firedheater, the radiative heat load on the tubes including possible flame impingement, the amount of heat transported to the convection section of the heater and the formation of NO_x.