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 dilution with nitrogen. A specific device for the condensation of cracking effluents was used for the fractionated recovery of liquid and gaseous effluents, which were analyzed on-line by an infrared analyzer and by gas chromatography. The cracking products in the liquid effluent were identified by gas chromatography/mass spectrometry coupling. The effects of temperature on the cracking reaction were studied for a constant residence time of 320 ms and a constant dilution rate of 13 moles of nitrogen/mole of feedstock. The principal products observed were linear 1-olefins, n-paraffins, and unsaturated methyl esters. The gas fraction 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 degrees C.