Dr. Satyen Kumar Das - IOCL R&D Centre
Since the inception of petroleum refining industry, Delayed coking has been the most widely used process for heavy oil upgradation. Worldwide, the deteriorating crude quality has resulted in higher yield of heavy residue with increase in contents of conradson carbon and other impurities, such as sulphur, nitrogen and metals.
Meanwhile, abundantly available renewable waste biomass is being explored extensively in India & other parts of world as a sustainable and low carbon footprint energy source of the future. The thermo chemical conversion of biomass is also one of the promising routes amongst renewable energy options for future. Thermo chemical conversion processes can be by gasification, pyrolysis and direct liquefaction. The biomass pyrolysis is an attractive option for India because solid waste biomass can be readily converted into liquid products through decentralized units to avoid costly transportation of low density biomass. The heavy bottom liquid product, called biomass pyrolysis oil generated from this process is akin to the petroleum residue in various aspects like CCR.
The present paper focuses on an improved process in which bio-oil obtained from fast pyrolysis of different sources of lignocellulosic biomass is added along with heavy hydrocarbon feedstock to see the impact on product yields in Delayed coking units. Bio-oil derived from fast pyrolysis of lignocellulosic biomass is composed of a complex mixture of oxygenated compounds, which poses challenge for utilization as a feed component along with feed to Delayed coking process. Accordingly, a study was undertaken to evaluate the impact of bio-oil in varying proportion in feed to conventional Delayed Coker unit on product yields. The experimental results indicate that with inclusion of bio-oil in feed to Delayed coker unit, coke yield reduces up to certain percentage bio-oil in feed. The amount of coke reduction and the optimal point depend on the quality of base feed as well as the bio-oil along the operating window.