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http://dx.doi.org/10.5293/kfma.2015.18.6.019

The Analysis on Exergy Loss and its Reduction Methods in Steam Desuperheating and Depressurizing Process  

Yi, Joong Yong (Graduate School, Department of Mechanical Engineering, Suwon University)
Lee, Chan (Graduate School, Department of Mechanical Engineering, Suwon University)
Publication Information
The KSFM Journal of Fluid Machinery / v.18, no.6, 2015 , pp. 19-26 More about this Journal
Abstract
The present paper presented and applied an exergy analysis method to evaluate the magnitudes and the locations of exergy losses in the conventional desuperheating and depressurizing process of high pressure and temperature steam delivery system. In addition, for the reduction of exergy losses occurred in conventional process, the present study proposed new alternative processes in which the pressure reducing valve and the desuperheater of conventional process are substituted with steam turbine and heat exchanger, and their effects on exergy loss reduction and exergy efficiency improvement are theoretically investigated and compared. From the present analysis results, the total exergy loss caused in conventional desuperheating and depressurizing process accounted for 66.5% of exergy input and 85% of the total exergy loss was due to the mixing between steam and cold water(e.g desuperheating). However, it was shown from the present analysis results that the present alternative processes can additionally reduce exergy loss by maximum 92.7% of the total exergy loss in conventional process, and can also produce additional and useful energy, the electricity of 220.6 kWh and the heat of 54.3 MJ/hr.
Keywords
Exergy; Exergy Analaysis; Exergy Efficiency; Exergy Loss; Steam Utilization; $2^{nd}$ law of Thermodynamics;
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