Experimental Investigation on Coking Characteristics of China RP-3 Kerosene under High Temperature and Long-duration Conditions

Coking characteristics of China RP-3 under high temperature (above 650 degrees C) and long-duration (20 minutes) conditions, especially the effects of temperature, pressure, and inner diameter of cooling channels on coking amount were experimentally investigated. Temperature of kerosene in experiments varied from 650 degrees C to 730 degrees C, pressure varied from 1.8MPa to 3.5MPa, and the mass flow rate was approximately 120g/min. Results showed that temperature has a significant influence on coking amount. Even a small increment of temperature induces remarkable coke formation. However, pressure and inner diameter of the tube has a relatively little effect on it. The coking amount increases as pressure and inner diameter increase, but the increasing rate is decreasing. It is considered that inner diameter mainly affects residence time. When residence time increases to some extent, coking amount begins to grow slowly even stop increasing. This is resulted from two reasons. Firstly, the cracking conversion percentage reaches an upper limit when residence time is adequately long; secondly, coke gradually covers the inner wall of the tube, leading to isolation of kerosene from the metal surface to form coking.