Study of the Flash Cycle Using Liquid Heat Recirculation (FC-LHR) for Energy Saving in Industry

• Main Authors: A. Kishimoto, R. Fujisawa, M. Nishimura
• Format: Article
• Language: English
• Published: AIDIC Servizi S.r.l. 2014-11-01
• Series: Chemical Engineering Transactions
• Online Access: https://www.cetjournal.it/index.php/cet/article/view/4737

The flash cycle (FC) has been proposed as a power cycle for heat recovery at low temperature. The FC is not constrained by the pinch point of the heat exchanger in the heat source in contrast to the Rankine cycle (RC), because the temperature difference for heat exchange is reduced by sensible heat exchange. However, the energy efficiency of the conventional FC is insufficient because of the low efficiency of power generation. It is considered that the low efficiency is mainly due to the flash rate at low temperature being low theoretically. Moreover, the heat of the saturated liquid is not used sufficiently. Hence, an energy- saving FC was proposed as an improvement of the conventional FC in this research. The proposed FC includes not only an expander line from the flash evaporator to generate power, but also a liquid heat recirculation line from the flash evaporator to use the sensible heat of the saturated liquid. The liquid heat recirculation increases the efficiency of power generation.