第四章和前沿讲座2.pptVIP

Natural Gas Hydrates Jakob de Swaan Arons Professor Royal Dutch Shell Chair Chemical Engineering Department Tsinghua University, Beijing, China 19th September 2006 Royal Dutch Shell Shell Transport and Trading Company (British) and Royal Dutch Petroleum Company (Dutch) Contents What are gas hydrates Models, thermodynamics and phasebehavior Applications Conclusions What is a Gashydrate? Gashydrates Crystalline structures of water with cavities of molecular size, containing (hosting) molecules of compounds (guest) with boiling points mainly below and sometimes above room temperature. What are gashydrates? Interaction and Stability Various Gashydrate Structures Compare size of molecule and cavity Gashydrate flame Importance Nuisance Blessing ? Separations Scientific Formation of a hydrate plug They resemble ice, we find them in Nature. Natural gas hydrate reservoirs Stability and natural conditions Industrial question Dutch natural gas may contain up to 14% N2. Could hydrates act as a good separation agent? Scientific importance As we will see later, gas hydrates offer an extremely interesting example of a large family of so called inclusion compounds made up of host- and guest- molecules. Water Urea Hydroquinone Question What has the subject of Natural Gas Hydrates (NGH) to do with a course in Advanced Chemical Engineering Thermodynamics? Answer In dealing with NGH we can demonstrate the power and beauty of Applied, Molecular and Statistical Thermodynamics. Classical thermodynamics Presents broad relationships between macroscopic properties but it is not concerned with quantitative prediction of these properties. Example John M. Prausnitz Statistical thermodynamics Seeks to establish relationships between ma