Journal of Natural Gas Science and Engineering 84 (2020) 103627 Available online 20 September 2020 1875-5100/© 2020 Elsevier B.V. All rights reserved. Flare gas recovery by liquid ring compressors-system design and simulation Esmaeil Yazdani a , Javad Asadi b , Yasaman Hosseinzadeh Dehaghani a , Pejman Kazempoor b, * a School of Chemical, Petroleum and Gas Engineering, Iran University of Science and Technology (IUST), 16846-13114, Tehran, Iran b School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, USA A R T I C L E INFO Keywords: Flare gas recovery Liquid ring compressor Gas treatment Process design H 2 S removal ABSTRACT Flare gas emission is a critical issue in the oil and gas industry due to its signifcant environmental impacts. While there are currently available solutions that can minimize the environmental risks of such emission sources, the implementation of these technologies generally brings additional economic and environmental challenges. Among the available technologies, the liquid ring compressor (LRC) is a promising option as it can compress and treat the fare gas simultaneously. However, there are several fundamental questions regarding the best oper- ating conditions as well as the appropriate integration of such devices into a fare gas recovery system. This paper deals with the design of a fare gas recovery system consisting of liquid ring compressors and an aqueous amine solvent for the abatement of acid gases, mainly hydrogen sulfde. Three different system confgurations are investigated to fnd the optimal system layout for the effcient and continuous recovery of fare gas in a refnery complex. In the frst confguration, a simple compressor arrangement is considered without an amine recycling line between the compression stages. The second confguration involves an amine recycling line between the compression stages. Appropriate heat exchangers are added to cool down the amine recycling line in all compression stages in the last confguration. Results show that the amine consumption in the third confguration is 67% and 44% lower than the amine consumption in the frst and second confguration, respectively. However, due to the additional cooling duty, the total required power in the third confguration increases by about 58% and 53% compared to the frst and second confgurations, respectively. 1. Introduction Climate change mitigation is a global issue in the 21st century since anthropogenic greenhouse gas emissions from industrial activities have resulted in increasing temperature and negatively affect human eco- systems (Asadi and Jalali Farahani, 2018). Decreasing the detrimental emissions of all industrial plants is essential to meet the goal of limiting global warming to 1.5 ◦ C (Rogelj et al., 2016). Besides, global energy demand has dramatically escalated nowadays due to increase of the world population, industrial activities, and living standards, which highlights the importance of energy recovery and utilization in energy-intensive industries, such as the oil and gas industry (Asadi et al., 2018). Flaring of unwanted and waste gas streams is a common process in the oil production and hydrocarbon processing plants for safe operation during abnormal or maintenance situations. However, the faring pro- cess is leading to major environmental problems such as global warming and acid rain (Johnson and Coderre, 2012). Recent studies show that approximately 140 billion cubic meters of natural gas are annually fared by the petroleum industry, polluting the environment about 400 million tons of CO 2 equivalent per year (Hamidzadeh et al., 2020; Tahouni et al., 2016). If this amount of fare gas is recovered and used for power generation, it can approximately supply the annual electricity consumption of the African continent, which is equal to 750 billion kWh (The World Bank, 2020). Accordingly, the gas faring not only contrib- utes to adverse effects on the environment and people’s health, but also wastes a valuable source of hydrocarbons, which could be recovered and utilized in more proftable ways. Flare gases in the oil and gas industry fall into two main categories, i. e., associated gas and non-associated gas. The term “associated gas” refers to the gases originally dissolved in oil at the formation pressure and releases during the oil production as the operating pressure reduces from formation to the atmospheric pressure. Depending on its quality and quantity, this type of fare gas is mainly vented to the atmosphere. The term “non-associated gas” refers to gases collected during abnormal situations as well as start-up and shut-down operations. Due to its low quantity, this type of fare gas has a negligible environmental impact in comparison with the associated gas faring. Flare gas recovery (FGR) is considered as an effcient way to prevent * Corresponding author. E-mail address: pkazempoor@ou.edu (P. Kazempoor). Contents lists available at ScienceDirect Journal of Natural Gas Science and Engineering journal homepage: http://www.elsevier.com/locate/jngse https://doi.org/10.1016/j.jngse.2020.103627 Received 1 July 2020; Received in revised form 22 August 2020; Accepted 15 September 2020