simulation and techno-economic analysis of the integration of a combined heat and power system in a flare gas recovery unit – case study: tabriz oil refining company (northwest iran)

Combined heat and power (chp) systems can reduce the energy waste in various industries including oil, gas, and petrochemical plants. in this research, the feasibility of the establishment of a chp system in a flare gas recovery (fgr) unit is studied. the integration of chp system in fgr unit is investigated from economical, technical, and environmental viewpoints. the fgr unit of tabriz oil refining company which is located in northwest iran is considered as a case study. no such integration has been investigated previously. the simulation of the proposed system is performed using aspen-hysys software. rankine cycle is considered for the combined production of heat and power and water is utilized as the rankine cycle working fluid. the fuel needed by the chp system is supplied from the fgr unit. in order to more utilization of the fuel energy, the thermal energy of furnace flue gases is recovered through a regenerator heat exchanger. the simulation results showed that the proposed system is able to generate about 4 mw of electrical power and 16 mw of thermal power corresponding to 15.42% and 77.63% electrical and thermal efficiencies, respectively. moreover, 4,532 kg/h of hot steam with a temperature of 381.4 ˚c is produced by utilizing the furnace flue gases thermal energy. the results of this study showed a promising performance for the integration of a chp system in fgr unit of tabriz oil refining company. the present study may be a step forward towards the efficient use of energy sources. future works in this field can be done with a view to the practical integration of chp systems in fgr units.