Investigation Of Oxy-Fuel Retrofit In A 250 Kw Cen Boiler Using Refinery Gas

CATEGORY: CARBON CAPTURE
Investigation Of Oxy-Fuel Retrofit In A 250 Kw Cen Boiler Using Refinery Gas
Alexis Sevault, Morten Seljeskog
Alexis.Sevault@sintef.no
SINTEF Energy Research, N-7465; Trondheim, Norway
ABSTRACT
Oxy-fuel combustion, a useful CCS technology, offers a number of advantages, including high flame temperature, enhanced stability, low exhaust gas volumes, low fuel consumption and low NOx emissions. Authors studied the possibility of retrofitting typical refinery fired heaters to operate at oxy-fuel.
Such heaters are fired with various fuels, ranging from heavy oil to refinery gas, all of which are by-products of refinery processing. Previously, conventional commercial oil burners have been adapted for oxy-fuel operations and mounted on a horizontal 250 kW CEN-Central European Norm boiler, on the assumption that such a system would be sufficiently similar to a typical vertical fired heater system. Results have shown that standard industrial oil burners can easily be rebuilt and retrofitted for oxy-fuel conditions, achieving stable operations close to normal air-firing conditions. It was demonstrated that the resulting oxy-fuel flames could produce both flame temperatures and longitudinal radiative heat fluxes similar to air-fired conditions.
Authors here focus on using refinery gas as fuel. Since the gas is a by-product of refinery processes, the gas will differ both in availability and composition between refineries. A typical refinery gas composition was then selected, based on data from a few specific refineries, as well as data available from literature. For practical purposes related to the experimental setup, the mixture was then simplified down to four main components; 25 % H2, 42 % CH4, 25% C3H8, and 8 % N2. Although C2H6 and C2H4 were omitted from the original mixture, the double C-H binding properties from C3H8 will, to some extent, account for the same bond interactions. Experimental measurements were performed with the same instrumentation as in the previous work with light and heavy oil. In addition, CFD calculations with full reaction mechanism have been performed using Fluent to support the results and help explain the underlying physical and chemical phenomena.
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