Advances in Environmental Technology 4 (2017) 217-227 *Corresponding author. Tel: + 986152327070 E-mail address: b.raei@mhriau.ac.ir DOI: 10.22104/AET.2018.2340.1118 Advances in Environmental Technology journal homepage: http://aet.irost.ir Environmental sustainability enhancement of a petroleum refinery through heat exchanger network retrofitting and renewable energy 2 , Ali Ghannadzadeh 1 Behrouz Raei 1 Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran 2 Department of Chemical Engineering, Hamedan University of Technology, Hamedan, Iran A R T I C L E I N F O A B S T R A C T Article history: Received 16 July 2017 Received in revised form 19 May 2018 Accepted 20 May 2018 This paper presents a case study on the enhancement of environmental sustainability in a petroleum refining process based on an exergetic diagnostic approach. The Life Cycle Assessment (LCA) pinpointed crude oil production and electricity generating systems as the main sources of environmental unsustainability. The existing hot utility demand of the process is 78.4 MW with a temperature difference of 40°C, where the area efficiency of the existing design is 0.7254. The targeting stage sets the minimum approach temperature at 18.96 °C, thereby establishing the scope for potential energy savings. The suggested design option with a total energy demand of 109,048 kW, the same as the existing one but 72,699 kW higher than the target, needs a 17,873 m 2 area in 38 exchangers. Notably, this requires 2,914 m 2 less surface area, suggesting the practicality of the project with a limited number of modifications such as the repiping of the existing exchanger units. Moreover, to enhance further the sustainability of the petroleum refining process, the possible solutions such as the renewables were evaluated through various scenarios; thus, resulting in a reduction in the environmental impacts from 2.34E-06 to 2.27E-06 according to ReCiPe, and thus paving the way towards a sustainable petroleum refining process. Keywords: Environmental sustainability Energy integration LCA Exergy Petroleum refinery 1. Introduction In spite of the importance of the petroleum refining process, there are few examples in the literature that use exergy analysis on a stand-alone basis to enhance the environmental sustainability of this process. Still, a limited number of case studies exist that take into account the process and utilities. Furthermore, production steps such as transportation should be included as it makes up the main philosophy of the LCA, which is applied to the petroleum refining process. Examples of such include the environmental impact assessment and its minimization in a refinery [1] as well as an ontology-enhanced LCA of an oil refinery [2]. Nevertheless, not a single study in the literature combines the exergetic method and LCA to enhance the sustainability of the industrial petroleum refining processes. This paper presents the first view on the application of an exergetic LCA to the petroleum refining process and the added benefit it can bring. In this regard, this work is based on the CExD indicator [3], and the objective is to pave the way towards an environmentally sustainable petroleum refining process. Unlike the existing studies on the life cycle of the petroleum refining process, this research emphasizes the utility systems such as the power generation system. Furthermore, the scenario starts with a short-term solution such as the so-called clean fossil energy (e.g. natural gas), and then present scenarios where the renewables are added to the power mix in a stepwise approach to avoid any perturbation in the system. Crude oil distillation systems are among the largest energy consumers in chemical industries. Consequently, the recovery of relatively small quantities of heat can accumulate to become significant energy savings. One of the most efficient ways to reduce energy consumption towards sustainability is to remove the bottlenecks of the existing process plants. Generally, the best debottlenecking occurs via improved heat recovery systems through the retrofitting of the heat exchanger network (HEN). In fact, the retrofitting of the HEN in crude