This paper describes the development and prototype performance of a novel combustor configuration, the Stagnation Point Reverse Flow (SPRF) combustor, for a direct steam generation system employing low quality solid fuels. The fuel used in the current work is pulverized petroleum-coke, a carbonaceous solid with low volatile content and high percentages of carbon and sulfur. Pulverized pet-coke is mixed with water to form a slurry, which is then fed into the combustor. Stable, self-sustained combustion of oxygen and petroleum-coke has been achieved at a nominal firing rate of 14 kg/h of petroleum-coke corresponding to a thermal power of 0.13 MW (440 kBTU/hr), at a power density of ～20 MW/m~3 (20 MBTU/hr/ft~3) and with a peak combustion efficiency of 81%. The effect of various operational parameters, including: loading, equivalence ratio and water content in slurry, on combustion efficiency and combustor stability were also investigated. Stable (self-sustained) combustion was attained for a wide range of equivalence ratios and loadings, but with a smaller range of water content and particle size. The response of the system to operational variations was also successfully analyzed with a simple, one-dimensional Plug Flow Reactor model.
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