A mixture of H2 and CO in volume ratio of two to one was used to simulate dissociated methanol(DM). The combustion of pre-mixture of natural gas(60%) and DM(40%) with diluent gases N2 and CO2 was analyzed at the initial temperature of 343 K and the initial pressure of 0.3 MPa in terms of combustion pressure

the maximum combustion pressure

explosion index and critical radius. The comparison of the combustions of different pre mixtures of natural gas(100%

60% and 20%)

DM(0%

40% and 80%) and air were experimentally conducted at the same initial temperature and pressure without diluent gases. The results show that DM has the function of accelerating pressure rise

promoting combustion

shortening combustion duration and advancing the formation of cellularity

but it will also reduce the maximum combustion pressure at and around the stoichiometric ratio

while the diluent gases have the opposite effects on combustion

such as decreasing the maximum combustion pressure and explosion index. In addition

CO2 is stronger than N2 in the suppression of combustion.