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http://dx.doi.org/10.7842/kigas.2014.18.4.13

Thermodynamic Analysis on Hybrid Turbo Expander - Heat Pump System for Natural Gas Pressure Regulation  

Sung, Taehong (School of Mechanical Engineering, Pusan National University)
Kim, Kyoung Hoon (School of Mechanical Engineering, Kumoh National Institute of Technology)
Han, Sangjo (Dept. of Mechanical & Automotive Engineering, Seoul National University of Science & Technology)
Kim, Kyung Chun (School of Mechanical Engineering, Pusan National University)
Publication Information
Journal of the Korean Institute of Gas / v.18, no.4, 2014 , pp. 13-20 More about this Journal
Abstract
In natural gas distribution system, gas pressure is regulated correspond to requirement using throttle valve which is releasing huge pressure energy as useless form. The waste pressure can be recovered by using turbo machinery devices such as a turbo expander. In this process, excessive temperature drop occurs due to Joule-Thompson effect during the expansion process. Installing natural gas boiler before or after the turbo expander prevents temperature drop. Fuel cell or gas engine hybrid system further improve the efficiency, but 1~2% of total transporting natural gas is used for operating the hybrid system. In this study, a heat pump system is proposed as a preheating device which can be operated without using transporting natural gas. Thermodynamic analysis on evaporating and condensing temperatures and refrigerants is conducted. Results show that R717 is proper refrigerant for the hybrid system with high COP and low turbine work within the defined operating conditions. In domestic usage in Korea, the heat pump system has more economic feasibility owing to natural gas being imported with a high price of LNG form.
Keywords
pressure regulation; waste pressure; turbo expander; heat pump; refrigerants; hybrid system; net profit comparison;
Citations & Related Records
Times Cited By KSCI : 3  (Citation Analysis)
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