Fouling and gasification studies

点击翻译按钮获取中文摘要

Deposition of solids onto surfaces of heat exchangers and other processing equipment is costly in terms of energy and operating efficiency. If root causes of fouling can be established, operating or design changes can be made to mitigate the problem, reducing energy loss and CO2 emissions. Deposition rates are often controlled by attachment of foulants to the surface, and for a given fluid, hydrodynamics, temperatures and surface properties are all important. Our general objective is therefore to elucidate the working mechanisms of fouling in petroleum and other process streams and to obtain a quantitative expression for the rate of fouling which operators can then use to control fouling. The approach is to use batch reactors for reaction and precipitation studies, followed by measurements of thermal fouling rates in re-circulation flow loops under defined flow and temperature conditions. Effects of process variables on rates and deposit properties are established. Models are used to express results and make predictions of rate behaviour. Detailed characterization of fluids aand deposits is necessary to identify mechanisms. Tools include solvent fractionataion of deposits and fluids, ultimate species analysis, asphaltene floccuation titrations, thermogravimetric analysis, scanning microscopy and the like. Topics coverd in this proposal include the role of iron sulphide formation in coke deposition from sour oil streams, the influence of fluid flow parameters on deposition in the adhesion regime, and the link between coking kinetics and the deposition process in flowing fluids. Continuing research in biomass gasifictaion and pyrolysis is also described.