Fouling and gasification studies

在热交换器和其他加工设备的表面上沉积固体在能源和操作效率方面是昂贵的。如果能够确定结垢的根本原因，就可以通过改变操作或设计来缓解问题，减少能量损失和二氧化碳排放。沉积速率通常由附着在表面的杂质控制，对于给定的流体，流体动力学、温度和表面性质都很重要。因此，我们的总体目标是阐明石油和其他工艺流中结垢的工作机制，并获得结垢率的定量表达式，以便操作人员可以使用该表达式来控制结垢。方法是使用间歇式反应器进行反应和沉淀研究，然后在确定的流量和温度条件下测量再循环流动回路中的热结垢率。确定了工艺变量对速率和镀层性能的影响。模型用于表达结果并对速率行为进行预测。流体和沉积物的详细表征是确定机制所必需的。工具包括沉积物和流体的溶剂分馏、最终形态分析、沥青质絮凝滴定、热重分析、扫描显微镜等。本提案涵盖的主题包括：含硫铁在酸性油流中沉积焦炭中的作用，流体流动参数对黏附状态下沉积的影响，以及焦化动力学与流动流体中沉积过程之间的联系。还描述了生物质气化和热解的持续研究。

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.