Studies of high-pressure n-butane oxidation with CO₂dilution up to 100 atm using a supercritical-pressure jet-stirred reactor

A novel supercritical-pressure jet stirred reactor (SP-JSR) was 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 CO₂ dilutions at pressures of 10 and 100 atm and over a temperature range of 500 K-900 K were conducted using the SP-JSR. The experiment showed that at 100 atm, a weak NTC behavior was observed and the intermediate temperature oxidation was shifted to lower temperatures. Also, the results showed that CO₂ addition at supercritical conditions slowed down the fuel oxidation at intermediate temperature while had minimal effect on the low temperature oxidation. The Healy model under-predicts the NTC behavior and shows little sensitivity of the effect of CO₂ addition on the n-butane oxidation. Reaction pathway and sensitivity analyses exhibited that both the low and intermediate temperature chemistries are controlled by RO₂ consumption pathways.