PRODUCTION OF HYDROCARBONS BY PYROLYSIS OF METHYL-ESTERS FROM RAPESEED OIL

The pyrolysis of a mixture of methyl esters from rapeseed oil has been studied ina tubular reactor between 550 and 850 degrees C and in dilu tion with nitrogen. A specific device for the condensation of cracking effluents was used for the fractionated recovery of liquid and gaseou s effluents, which were analyzed on-line by an infrared analyzer and b y gas chromatography. The cracking products in the liquid effluent wer e identified by gas chromatography/mass spectrometry coupling. The eff ects of temperature on the cracking reaction were studied for a consta nt residence time of 320 ms and a constant dilution rate of 13 moles o f nitrogen/mole of feedstock. The principal products observed were lin ear 1-olefins, n-paraffins, and unsaturated methyl esters. The gas fra ction also contained CO, CO2, and H-2. The middle-chain olefins (C-10- C-14 cut) and short-chain un-C saturated esters, produced with a high added value, had an optimum yield at a cracking temperature of 700 deg rees C.