Exhaust Gas Heat Utilization Employment Of Water-сooled Gas Pipes

Abstract

Exhaust heat recovery is one of several ways to improve the efficiency of gas-compressor units. Recuperators and boilers used for these purposes are placed on the way of flue gas to provide a cross-flow of heat exchange area. The heat exchange area should be large due to low heat exchange coefficient numbers between a surface of a heat exchanger and a flue gas flow. This factor can result in large pressure drops of a gas flow and can cause significant gas turbine capacity reduction. Heat exchanger placed on the walls of a gas pipe section has smaller influence on the turbine capacity but its heat exchange area can not be large. From the other hand gas power plants are often a big distance away from heavy heat consumers, therefore large heat capacities of heat utilizers could not be in demand. It means that the main goal of the redundant heat usage is hot water supply and heating of operating platforms and several adjacent objects. In this work three different constructions of recuperative heat utilizers were examined. All of them were placed on the walls of a flue pipe section. The cooling heat carrier was water. An objective function was used to compare thermal and hydraulic characteristics of recuperators such as heat capacity and electricity need for water pumping and turbine capacity loss. Multiple checking calculations were made for each construction type of a heat exchanger. Conclusions about the best construction of a heat utilizer were made based on computational results.