Optimization analysis of liquefaction cycles for nitrogen

Simulation is carried out on Claude cycle, modified Claude cycle eliminating last heat exchanger and modified Claude cycle eliminating first heat exchanger by process design software Aspen Hysys®. Modified Claude cycle eliminating last heat exchanger has been found suitable for a turboexpander based nitrogen liquefier with medium capacity. Analysis is carried out to access the role of different component efficiencies in predicting overall system efficiency at the design and off design conditions. In this analysis optimization has been done for maximum yield at the different operating pressures using same heat exchanger effectiveness and turboexpander efficiency. Optimum pressure of compression, heat exchanger effectiveness and mass fraction diverted through turboexpander and turboexpander efficiency was found out.