Technological and economical analysis of flare recovery methods, and comparison of different steam and power generation systems

Abstract

One of the most important environmental issues in the oil, gas, and petrochemical industries is the appropriate disposal of waste hydrocarbon gases in industrial units. The most commonly employed method for the safe disposal of these gases is burning them in flare stakes followed by releasing them in the environment. To date, various methods and procedures, preponderantly focusing on the modification of the units which generates the gases directed to flare stacks, have been introduced to reduce and/or recover these gases. These methods face with a number of issues, such as the lack of economic justification, high systemic risks, and operational limitations. In this research, four methods for flare gas recovery have been introduced, namely high-pressure steam generation, steam turbine, electricity and heat generation, and combined cycle, and they have been simulated using Aspen HYSYS software. According to the results, producing electric power from flaring gases in the last three methods was 7.323 e+5, 4.350 e+5, and 1.442e+006 kW, respectively, and it caused less pollution and saved energy. In order to assess the economic justification of the proposed methods, the economic assessment was conducted for each method, and economic return was calculated. The rate of investment return for the four processes of the high-pressure steam generation, steam turbine, electricity and heat cogeneration, and combined cycle was 18.66, 19.76, 25.79, and 31.97, respectively, reflecting the high economic return of the combined cycle method.