Dynamic behaviors of coke deposition during pyrolysis of China RP-3 aviation fuel

摘要

China RP-3 aviation fuel was used as an endothermic fuel to pyrolyze at temperatures up to 640°C in an electrically heated horizontal channel with an internal diameter of 4 mm. Dynamic behaviors of coke deposition was experimentally investigated. Coking process was considered to the net result of two simultaneous sub-processes: a deposition process and a removal process. Results indicated that coking process was a dynamic behavior with randomness. During duration period of coking run, the parameters especially the pressure drop across the test channel and the fuel temperature in some degree oscillated. The wall temperature of the test channel in a small scale period was unpredicatable, due to the random coke accumulation with different coking rate, and even the random coke peeled off in a sudden. However, repeated experiments were carried out to get reliable results, and multi-experiment obtained some regular patterns of coking behaviors. Opposite to the general realization that coke is a thermal layer to reduce heat transfer, surface deposition in the test channel enhanced the heat transfer during pyrolysis process of China RP-3 aviation fuel. Along the length of test channel, more coke was found to deposit in the front part with fuel temperature less than 350°C. The coking rate (the net result of deposition rate and removal rate) increased by step during coking processes.