chemical engineering research and design 9 1 ( 2 0 1 3 ) 1272–1283 Contents lists available at SciVerse ScienceDirect Chemical Engineering Research and Design journal h om epage: www.elsevier.com/locate/cherd Techno-economic analysis of potential natural gas liquid (NGL) recovery processes under variations of feed compositions Mesfin Getu a , Shuhaimi Mahadzir b , Nguyen Van Duc Long c , Moonyong Lee c,* a Department of Chemical Engineering, Curtin University of Technology, CDT 250, 98009 Miri, Sarawak, Malaysia b Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia c School of Chemical Engineering, Yeungnam University, 214-1 Dae-dong, Gyeongsan, Gyeongbuk 712-749, Republic of Korea a b s t r a c t This paper presents the different process schemes used for known NGL recovery methods with respect to their economic performance. The original turbo-expander (ISS) was considered as base case plant. The GSP, CRR and RSV process schemes focus on improvement at the top of the demethanizer column. The IPSI-1 and IPSI-2 schemes focus on the bottom of the demethanizer column. All the process schemes were initially built using Aspen HYSYS with a common set of operating criteria. Numerous simulation runs were made by taking various typical feed compositions classified as lean and rich. The economic assessment for each process scheme was later made by considering the capital cost, operating cost and profitability analysis. Results showed that the IPSI-1 process scheme gives the best economic performance with lowest TAC and payback time compared to the other process schemes. On the other hand, the RSV process gives higher TAC and payback time compared to others. © 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. Keywords: Natural gas liquid; NGL recovery process; Demethanizer; Turbo-expander process; Gas processing; Techno- economic assessment; Feed composition effect 1. Introduction Technology trends in gas processing industries have emerged since early 1900s. During those times, heavier hydrocarbons from natural gas streams are removed by compression and cooling methods. A number of changes have been made after that to improve the process efficiency that contributes to the incentive for high recovery of the desired products from the plant, such as refrigerated oil-absorption (Lee et al., 1999). However, a major leap in gas processing industries was the introduction of a turbo-expander design, which is also known as an Industry-Standard Single-stage (ISS) process scheme. This process scheme has certain limitations in terms of oper- ational flexibility and overall recovery performance (Rahaman et al., 2004). The carbon dioxide freezing problem in the demethanizer column was another issue associated with the turbo-expander process scheme (Lynch et al., 2002). Due to ∗ Corresponding author. E-mail address: mynlee@yu.ac.kr (M. Lee). Received 20 May 2012; Received in revised form 19 December 2012; Accepted 24 January 2013 these and many other factors, a number of various process scheme options have been evolved and are available in public domain. Among these, only few of them are licensed under the U.S. Patent. The most known ones are those which are developed by Ortloff and IPSI Companies. The gas sub-cooled (GSP), cold residue (CRR) and Recycle vapor-split (RSV) are all owned by Orloff Company. The enhanced NGL recovery pro- cesses (IPSI-1 and IPSI-2) belong to IPSI Company. The GSP process scheme was developed by Campbell and Wilkinson (1981) as an improvement to the ISS process scheme. This process scheme uses a split-vapor feed as a reflux to the rectification section of the demethanizer column. Accordingly, the portion of the feed gas is first condensed and sub-cooled before it is flashed and introduced as a top liq- uid feed reflux to the demethanizer column. The cold liquid reflux liquid will condense and absorb ethane and propane rising up through the column and thereby allow higher recov- ery. The other advantage of the cold reflux liquid stream is that it can significantly reduce the risk of carbon dioxide solid 0263-8762/$ – see front matter © 2013 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.cherd.2013.01.015