Analysis of four end high temperature membrane air separator in a supercritical power plant with oxy type pulverized fuel boiler

In this article computational algorithm and exemplary results for a model of an air separation unit (ASU) with "four end" high temperature membrane (HTM) were presented. First, the software environment for building of a "four end" membrane separator model was chosen. Then, a model of an air separation unit was created and preliminary calculations were made on that model. The air separation unit structure consists of a "four end" membrane, heat exchanger, electrical generator, air compressor and expander. Parameter that determines all flows in the ASU model is the oxygen mass flow rate. This mass flow rate is approximately the same as oxygen mass flow rate feeding oxy boiler working in a 460 MW power plant. The most important step of this paper was the integration of a model of pulverized fuel boiler in the oxy-combustion technology and the air separation unit model by sending flue gas from boiler to ASU. The characteristics of ASU such as power and efficiency as a function of the oxygen recovery rate were made. Maximal value of oxygen recovery rate was calculated. The difference between optimal compressor pressure ratio of the autonomic gas turbine and of the air separation unit are presented in this paper.