PNNL

Abstract

A field-deployable process for generation of clean desulfurized fuel from JP-8 feedstock is described. The process employs a compact hydrodesulfurization unit, operated in the vapor phase using steam reformate provided by a downstream steam reformer as a replacement for hydrogen cofeed gas. The process can include a microchannel distillation unit upstream of the hydrodesulfurizer unit, which allows use of a lighter feed fraction to be processed in place of the full JP-8. Since the lighter cut contains less refractory sulfur components, the overall process can readily reduced sulfur content from 1300ppm to approximately 300ppb. The novel microchannel distillation concept is described and performance data for the unit, operating as a rectifier, are provided. Subsequent hydrodesulfurization of full JP-8 fuel without the microchannel distillation unit was also studied. The effect of various operating parameters on the overall hydrodesulfurization performance as well as the conversion of some individual sulfur components such as 2,3-dimethyl-benzothiophene, 2,3,5-trimethyl-benzothiophene and 2,3,7-trimethyl-benzothiophene, are investigated. Steam content at 30 mol% or less is found to improve hydrodesulfurization performance compared with dry reformate. At even higher concentrations of steam, hydrodesulfurization performance decreases. Both the role of water gas shift reaction, and the possible reversible poisoning of the surface by H2O, may be involved in explaining these results.