FACTORS AFFECTING THE YIELDS PRODUCED FROM THE 2-STAGE PYROLYSIS OF EGYPTIAN BITUMEN

The two-stage pyrolysis of crude oil refinery vacuum residues using a batch type reactor has been performed. In order to obtain a maximum yield of ethylene and propylene from the Egyptian residues, bitumen (fraction 80/100) was further separated into six fractions. The fractions are saturated, monoaromatic, biaromatic, polyaromatic, resin and asphaltene products. Each of these fractions was investigated independently as a feedstock for the two-stage pyrolysis technique under the following conditions: τ1 = 25 min, τ2 = 3 s, T1 = 450°C and T2 = 750°C. A mathematical expression giving the yield as a function of τ that fits the present experimental data has been derived by means of the least squares method: y = a0 + a1(τ1 - 20) + a2(τ1 - 20)2 + a3(τ1 - 20)3. Applying the least squares method, the experimental data on the saturated and unsaturated hydrocarbon gaseous pyrolyzate at different first-stage temperatures can be mathematically formulated by the following expression: y = a0 + a1(T1 - 400) + a2(T1 - 400)2 + a3(T1 - 400)3. While applying the least squares method, the experimental data on the saturated and unsaturated gaseous pyrolyzate of different severity functions (Sf) can be mathematically formulated by the following expressions: y = a0 + a1(Sf - 1332) + a2(Sf - 1332)2 + a3(Sf - 1332)3 for saturated, monoaromatic and resin fractions while y = a0 + a1(Sf - 1428) + a2 (Sf - 1428)2 + a3(Sf - 1428)3 for biaromatic, polyaromatic and asphaltene fractions. © 1990.