Experimental and kinetic modeling studies of polyoxymethylene dimethyl ether (PODE) pyrolysis in jet stirred reactor

Polyoxymethylene dimethyl ethers (DMMn) is regarded as a potential alternative fuel for transportation utilization. The jet stirred reactor (JSR) pyrolysis of DMM1-3 was studied at temperatures of 450 similar to 1080 K and pressures of 1.03 atm with the residence time (tau) of 2 s. A gas chromatography/mass spectrometry (GC-MS/FID) was used to detect and provide reliable pyrolysis experimental data. Seven key pyrolysis products were detected and measured in the present work, including fuel, methyl formate, methanol, acetaldehyde, methane, ethane and ethylene. A detailed kinetic model of DMM1-3 pyrolysis was elaborated. Both rate of production (ROP) and sensitivity analysis were performed to reveal the DMM1-3 pyrolysis processes. Results show that the chemical kinetic simulation can reproduce the consumption of fuel and most intermediate species reasonably well. With the increase of n from 1 to 3 inside DMM1-3, the reactivity increases evidently and the initial pyrolysis temperature decreases significantly, which is mainly resulted from different fuel-specific chain initiation reactions of DMM1-3 . Methane and methyl formate are two detected key species with relatively significant concentrations. It was revealed that the fuel-specific chain initiation reactions of DMM1-3 can also significantly affect the production and consumption paths of methyl formate. In addition to the major production and consumption paths of formaldehyde, two key competitive channels were found to perform relatively high negative sensitivity to formaldehyde production of DMM2 and DMM3.