Contents lists available at ScienceDirect Applied Energy journal homepage: www.elsevier.com/locate/apenergy Dual mixed refrigerant LNG process: Uncertainty quantifcation and dimensional reduction sensitivity analysis Muhammad Abdul Qyyum a,1 , Pham Luu Trung Duong b,1 , Le Quang Minh c,1 , Sanggyu Lee d , Moonyong Lee a, ⁎ a School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749, Republic of Korea b Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore c Department of Chemical and Biomedical Engineering, West Virginia University, Morgantown, WV 26506, USA d Gas Plant R&D Center, Korea Gas Corporation, Incheon 406-130, Republic of Korea HIGHLIGHTS • Uncertainty quantifcation and sensi- tivity analysis for LNG process. • Standard Monte Carlo (MC) method is utilized. • Relative percentage of the Sobol total efect indices for DMR LNG process. • Probability distribution of the ap- proach temperature for DMR lique- faction process. • Global sensitivity analysis with less computational efort. GRAPHICALABSTRACT LNG-DMR process MITA 1 (oC) -25 -20 -15 -10 -5 0 5 Density function f 0.0 0.2 0.4 0.6 0.8 1.0 Specific energy (kW) 0 5 10 15 20 25 30 Density function f 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 MITA 2 (oC) 0 1 2 3 4 5 Density function f 0.0 0.2 0.4 0.6 0.8 Uncertainty quantification and global sensitivity analysis Uncertainty quantification Global sensitivity analysis ARTICLEINFO Keywords: DMR natural liquefaction process Uncertainty quantifcation Sensitivity analysis Monte Carlo Multiplicative dimensional reduction method ABSTRACT The dual mixed refrigerant (DMR) liquefaction process is complicated and sensitive compared to the competitive propane pre-cooled mixed refrigerant liquefed natural gas (LNG) process. When any uncertainty is introduced to the process operation conditions, it is necessary for the DMR process to be re-optimized to maintain efcient operation at a minimal cost. However, in actual operation, re-optimization is a challenging task when the process operational input variables are varied, typically owing to the lack of information regarding the nature, impact, and levels of uncertainty. Within this context, this study investigates the uncertainty levels in the overall energy con- sumption and minimum internal temperature approach (MITA) inside LNG heat exchangers with variations in the operational variables of the DMR processes. Moreover, a global sensitivity analysis is conducted to identify the infuence of random inputs on the process performance parameters. The required energy is signifcantly infuenced by the variations in the variables in the cold mixed refrigerant (approximately 63%), while changes in the warm mixed refrigerant (WMR) section only slightly afect the uncertainty of the required specifc energy. Furthermore, the probability distribution of the approach temperature (MITA1) inside the WMR exchanger is mainly afected by changes in the compositions of methane, ethane, and propane, as well as the high pressure of the cold mixed refrigerant (approximately 97%). Conversely, the fow rate of ethane and low pressure of the WMR signifcantly afect the uncertainty of the approach temperature (MITA2) inside the cold mixed refrigerant exchanger. https://doi.org/10.1016/j.apenergy.2019.05.004 Received 4 February 2019; Received in revised form 5 April 2019; Accepted 1 May 2019 ⁎ Corresponding author. E-mail address: mynlee@yu.ac.kr (M. Lee). 1 These authors contributed equally. Applied Energy 250 (2019) 1446–1456 Available online 16 May 2019 0306-2619/ © 2019 Elsevier Ltd. All rights reserved. T