ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Evaluation of small-scale liquefied natural gas (SSLNG) processes: advanced exergoeconomic analysis

Mostafa Delpisheh, Hamid Saffari, Seyyed Mostafa Hosseinalipour, and Mehdi Mehrpooya

School of Mechanical Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

E-mail: mehrpoya@ut.ac.ir

Received: 20 June 2022  Accepted: 30 July 2022

Abstract:

One of the principal challenges facing today’s society is the necessity to discover more environmentally friendly, futureproof energy sources. In this scope, natural gas, ensued by liquefied natural gas, is an ever more important cornerstone on the path towards a low-carbon economy. The present study evaluates the processes employed for small-scale liquefied natural gas (SSLNG) plants. Three processes, namely, dual expansion, pre-cooled PRICO, and nitrogen expansion, and thereof, conventional and advanced exergoeconomic analyses are applied to appraise the performance of the processes. In the energy analysis, three parameters were assessed, namely, specific power consumption, the figure of merit, and the coefficient of performance. The precooled PRICO and the nitrogen expansion processes were the performant in the first two, and the third, respectively. The exergy efficiency in the three processes was 74%, 76%, and 75%, respectively. In all processes, the exogenous exergy destruction share was higher than endogenous, meaning that the internal irreversibility in other equipment substantially affects the exergy destruction in the equipment under analysis. The pre-cooled PRICO process had the highest exergoeconomic factor followed by the dual expansion process, both near 0.3. The highest avoidable endogenous exergy destruction costs in all processes were pertinent to the air coolers, gauged at 862.33, 308.23, and 71.67 $/h, respectively. Also, the highest avoidable endogenous investment cost rates were associated with C1, C2, and T1 equipment measured at 68.958, 49.42, and 3.38 $/h, respectively. The modified exergy efficiency was higher than the conventional exergy efficiency in all components of the three processes.

Graphical abstract

Keywords: LNG; Advanced exergoeconomic analyses; Small scale; Exergy efficiency; Exergy destruction

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02408-5

Chemical Papers 76 (12) 7373–7394 (2022)