Improving Energy Efficiency in Ammonia Plant Using Pinch and Exergy Analysis

This paper investigates a research on the energy efficiency improvement in the ammonia process. Combined chemical, heat and power system can be applied as one of the common practice to improve the thermodynamic efficiency of ammonia plant. Having applied a gas turbine and improved the heat integration through the process, one can generate electricity using available mechanical exergy of the ammonia reactor outlet stream. In this regard, the exergy loss index for the whole process including the heat transfer and gas turbine systems is minimized using combined pinch and exergy analysis. Afterwards, the optimal conditions of gas turbine outlet stream are obtained and the heat recovery is maximized through the network. The results showed that 4 MW net shaft work is produced applying the gas turbine, however, 7350 kW hot utility should be added to the plant in order to preheat the reactor inlet stream, which can in turn be supplied by improving the heat recovery. The new configuration is led to a significant reduction in exergy loss of the process by 19% compared to the existing base case. Also, economic evaluation indicated that the estimated net income is 1051095 $/yr with an investment payback of 1.9 year

کلیدواژه ها:

Ammonia plant ، Combined Pinch and Exergy Analysis ، Gas Turbine ، Heat Integration ، Combined Heat and Power