Studies of high-pressure n -butane oxidation with CO2 dilution up to 100 atm using a supercritical-pressure jet-stirred reactor

A novel supercritical-pressure jet stirred reactor (SP-JSR) is developed to operate up to 200 atm. The SPJSR provides a unique platform to conduct kinetic studies at low and intermediate temperatures at extreme pressures under uniform temperature distribution and a short flow residence time. n -Butane oxidations with varying levels of CO 2 dilutions at pressures of 10 and 100 atm and over a temperature range of 500-900 K were conducted using the SP-JSR. The experiment showed that at 100 atm, a weak NTC behavior is observed and the intermediate temperature oxidation is shifted to lower temperatures. Furthermore, the results showed that CO 2 addition at supercritical conditions slows down the fuel oxidation at intermediate temperature while has little effect on the low temperature oxidation. The Healy model under-predicts the NTC behavior and shows little sensitivity of the effect of CO 2 addition on the n-butane oxidation. Reaction pathway and sensitivity analyses exhibit that both the low and intermediate temperature chemistries are controlled by RO 2 consumption pathways. In addition, the reactions of CH 3 CO ( + M) and CH 3 CO + O 2 become important at 100 atm. The results also revealed that fuel oxidation kinetics is insensitive to the third body effect of CO 2 . The kinetic effect of supercritical CO 2 addition may come from the reactions involving H 2 O 2 , CO, CH 2 O, and CH 3 CHO, especially for the reactions of CO 2 + H and CO 2 + OH. (c) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.