Pressurized laser pyrolysis of coal

A set-up for the laser-induced pyrolysis of coal using the visible blue-green emission from an argon ion laser is described. The design of the pyrolysis cell allows buffer gas pressures up to about 10 bar enabling pyrolysis studies under pressurized conditions. The gaseous products formed in helium and the reactive atmosphere of hydrogen and deuterium have been identified by on-line gas chromatography/mass spectrometry. Deuterium has been utilized as a buffer gas at various pressures and the in situ deuteration of the products during the pyrolysis has been studied. In this way, mechanisms for the formation of unsaturated hydrocarbons have been disclosed and the results for ethylene formation are reported.