Effective utilization of low-grade steam in an ammonia-water cycle

摘要

Effective utilization of low-grade steam in a Rankine cycle power plant is one of the challenging tasks for researchers. In a condensing turbine, last few stages of the turbine operate in two phase region leading to losses due to flow of wet steam, which results loss of work in low pressure turbine. Either wet or saturated steam normally called low grade is difficult to handle in a steam turbine due to its higher specific volume. Major portion of the heat in the cycle is rejected to cooling water, which results in thermal pollution of the environment and higher energy loss. Ammonia-water cycle or Kalina cycle is more efficient for the utilization of various low grade heat sources such as gas turbine exhaust gas, geothermal hot water, exhaust from steel plant etc. In this work, a new methodology was proposed for the utilization of low-grade steam in ammonia-water cycle to obtain a better power output and higher plant efficiency. The suggested ammonia-water cycle that utilizes low-grade steam produces higher-power output and it is more efficient than the Rankine steam cycle utilizing the low-grade steam and operates on a condensing mode. [PUBLICATION ABSTRACT]