Thermal Cracking of Hydrocarbons: Evaluation of Various Feedstocks

Abstract

Thermal cracking of naphtha, gas-oil, light hydrocarbons such as Ethane, Propane, Butane and their mixtures is an important process for production of Ethylene, Propylene, Butadiene and Aromatics which are basic feedstocks of petrochemical industries. Experiments were carried out in bench scale cracker which allows cracking of different hydrocarbon feedstocks. The report presents evaluation of various feed stocks experimentally and also by SPYRO model simulation. Several runs were carried out in bench-scale cracker unit with different operating conditions that would simulate commercial plant performance with respect to yields. The optimum run conditions for Ethane cracking are: Coil Outlet Temperature (COT) : 810 ; Water to Hydrocarbon ratio : 1; Residence time: 0.25s. The optimized process conditions for Naphtha feed are; COT: 810 , Ratio: 0.35, Residence time: 0.5 sec. In case of mixed hydrocarbon feed DMDS (Di methyl disulfide) addition was found effective than addition of DEDS (Di ethyl disulfide) as coke formation was reduced by addition of DMDS. For Cyclohexane cracking the yield of 1-3 Butadiene was more compared to other feeds. For Also effect of run length on coke formation was studied using naphtha as feed. Initial coking rate is very high which gradually decreases and then becomes constant. Simulations of different hydrocarbon feed were carried out in SPYRO model to study yield patterns of olefins.