Kinetic characteristics of high-pressure syngas release and spontaneous ignition at different temperatures

Abstract

To investigate the effect of initial temperature, initial vessel pressure and the ratio of hydrogen in the syngas on the spontaneous ignition of high-pressure syngas release, a series of experiments was conducted. The influence law and mechanism of the spontaneous ignition was investigated. The experimental results showed that the pressure in the tube presented an oscillating rise and then a slow decline after high-pressure syngas release. The pressure peak (Pmax) in positions 1 and 2 were 3.215 MPa and 2.620 MPa respectively when the initial vessel pressure was 6.0 MPa. With the increase of the initial temperature and pressure, the syngas shock wave in the tube propagated faster and the pressure peak reached was higher. The Pmax in positions 1 and 2 increased from 1.900 MPa to 1.605 MPa–3.851 MPa and 3.385 MPa respectively with the initial vessel pressure increasing from 3.0 MPa to 7.0 MPa at a temperature of 20 °C. As the initial temperature increased, the critical pressure required for syngas to spontaneous ignition became lower. The numerical simulation results showed that the flow velocity and turbulent kinetic energy of the flow increased with the initial temperature, initial vessel pressure and the ratio of hydrogen in the syngas increased. The maximum temperature rose gradually and spontaneous ignition occurred in a forward direction. In addition, spontaneous ignition was more likely to occur in the tube.