Studying a Multi-Stage Flash Brine Recirculation (MSF-BR) System Based on Energy, Exergy and Exergoeconomic Analysis

Due to the lack of natural water resources and high consumption of water in industries, desalination systems are good options to supply water demands, especially in regions with a water crisis. If these wastes are used in thermal desalination cycles, in addition to improving efficiency and reducing energy consumption, the production of environmental pollutants can also be reduced. In this paper, the multi-stage flash brine recirculation (MSF-BR) system of the Abadan refinery is investigated from energy-exergy-exergoeconomic viewpoints. In addition, the effects of top brine temperature (TBT), number of stages and ambient temperature on the performance of the system are evaluated. The results at maximum brine temperature show that with increasing the TBT, the exergy efficiency, gained output ratio (GOR) and distillate water production increase by 34%, 47% and 47%, respectively. It is also found that if the number of stages in the heat rejection section increases to more than six stages, GOR will decrease. The exergoeconomic analysis results reveal that the relative cost difference increases by 94% with an increase in the number of stages. Finally, it is concluded that by using the waste heat of a refinery complex for heating steam to run the desalination system, there is a 9103 $/year cost savings due to energy consumption reduction and 193 × 104$/year cost savings due to CO2 emission reduction

A new approach for enhancing performance of a gas turbine (case study: Khangiran refinery)

There are various methods which are commercially available for turbine air inlet cooling aiming to improve gas turbine efficiency. In this study a new approach has been proposed to improve performance of a gas turbine. The approach has been applied to one of the Khangiran refinery gas turbines. The idea is to cool inlet air of the gas turbine by potential cooling capacity of the refinery natural-gas pressure drop station. The study is part of a comprehensive program aimed to enhance gas turbines performance of the Khangiran gas refinery. The results show that the gas turbine inlet air temperature could be reduced in range of 4-25 K and the performance could be improved in range of 1.5-5% for almost 10 months.Gas turbine Inlet air cooling Gas turbine efficiency improvement Natural-gas pressure drop stations

Techno-Environmental Analyses and Optimization of a Utility Boiler Based on Real Data

A numerical simulation for analysis and optimization of the performance and NOx production was applied to a natural gas fuel boiler in South Pars Gas Complex. For this purpose, nine actual environmental and operational parameters of a boiler were measured and recorded every two hours and then averaged daily for a year. Using the thermodynamic laws, important parameters such as body and exhaust flue gas losses, as well as the thermal efficiency and exergy efficiencies of the combustor and boiler, were calculated for each day. The results show that, owing to changes in the environmental and operational conditions, the thermal and exergy efficiency of the boiler varied from 83% to 87% and 27% to 32%, respectively, during the year. In addition, by optimizing the excess air percentage, the thermal and exergy efficiencies could be increased by 1.5% and 3%, respectively, for most days of the year