Feasibility Assessment of South Pars Gas Condensate Utilization in the Production of Blended Fuels for Thermal Power Plants

Rising operating and maintenance costs, equipment corrosion, and the environmental consequences associated with the consumption of high-sulfur fuel oil in thermal power plants have highlighted the need to investigate upgraded fuel formulations. In this study, the feasibility of using gas condensate from Phases 4 and 5 of the South Pars field, both as a neat fuel and as a blending component for fuel oil and diesel fuel, was evaluated. For this purpose, fuel oil/condensate blends containing 10–50 vol% condensate and diesel/condensate blends containing 6, 10, and 20 vol% condensate were prepared, and their physical, chemical, combustion-related, safety, and stability properties were examined. In the blend containing 50 vol% condensate, the total sulfur content decreased from 4.28 to 2.28 wt%, the kinematic viscosity at 40 °C declined from 852.3 to 4.158 mm²/s, the asphaltene content decreased from 11.8 to 5.9 wt%, and the ash content was reduced from 0.075 to 0.038%, while the net heating value increased from 9,518 to 10,059 kcal/kg. However, the addition of only 10 vol% condensate reduced the flash point of the fuel oil from 79 °C to below 0 °C. Moreover, in the blend containing 50 vol% condensate, the Reid vapor pressure reached 8.60 psi and the mercaptan concentration increased to 1,300 ppm. The storage stability number also increased from 9.6 for the base fuel oil to 12.1–12.6 for the blends, indicating asphaltene instability. In the diesel/condensate blends, the flash point decreased from 58 °C to 7, −4, and −21 °C upon the addition of 6, 10, and 20 vol% condensate, respectively. Therefore, the use of gas condensate may be considered only when surplus condensate is available and provided that flash point, vapor pressure, mercaptan content, and asphaltene stability are carefully controlled and limited field-scale testing is conducted.