Application of Turbo-Expander for Greenhouse Gas and Air Pollutant Emissions Reduction Using Exergy and Economical Analysis

The effects of greenhouse gases (GHG) on the growth of global warming, and increase of GHG and air pollutant emissions for energy production have forced the need of energy recovery which is normally wasted in industrial plant. The present research work focused on the GHG and air pollutant emissions reduction employing pressure waste energy recovery. Pressure break-down via Joule-Thomson valve is a neat potential for waste energy recovery in gas refineries, which may also be provide by using a turbo-expander instead of commercial valves. Based on this ground, an exergy analysis is carried out for Joule-Thomson valve. The results showed that the exergy loss is higher than 6.5 MW and it is possible to recover about 1.9 MW of exergy loss. On the other hand, it was found that about 16900MWh of electrical energy can be produced by recovering the energy of waste pressure, which may leads to less consumption of the load and gas in refinery power unit. Consequently, equal the gas consumption reduction, 12056 ton CO2e of GHG and 54.6 ton of air pollutant emissions is reduced annually. Economical evaluation of utilizing a turbo-expander instead of a valve proved that this altering scenario is deducible and practical. Economical indexes, namely, IRR and NPV are found to be equal to 25.51% and 929571 US$, respectively. Moreover, sensitivity analysis conducted on each specific state certified the obtained results.