Methanation - With High Thermodynamic Efficiency Energy Recovery

摘要

Heat pipes could be utilized in the process of methanating synthesis gas from coal in two important ways. The first is in the methanator itself where the heat pipes are used for catalyst cooling, temperature control and high-temperature isothermal energy recovery. The second involves recovering thermal energy in the exit gas stream from the methanator and using it to preheat the methanator inlet stream and also to produce steam from condensed water from the exit stream.nThe methanator has the following unique characteristics. It is composed of a dense assembly of heat pipes with stacks of cylindrical pellets of a catalyst such as nickel/alumina intimately dispersed among them. Nickel concentration in the catalyst stacks is varied from 10 to 50% to limit the front end temperature within the methanator. Heat is extracted from the methanation reaction isothermally at temperatures approach¬ing the upper operating limits of the catalyst - approximately 750 to 800 K. Energy is transported by the heat pipe into a steam boiler where superheated steam is produced.