فهرست مطالب سعید قوامی گرگری

In this paper, a novel biogas steam reforming system for producing hydrogen is presented. The mixture of biogas contains a largepercentage of Methane, Carbon Dioxide,negligible amounts of other gases. A thermodynamic comprehensive modeling (energyand exergy) was done on the suggested system. The impact of various system parameters in the mixture of biogas such as,temperature,molar ratio of carbon dioxide to methane is also done on the hydrogen production rate, energy,exergyefficiencies of the entire system. The results show that by increasing the temperature of the steam reforming reaction in reactor, in aconstant molar ratio of carbon dioxide to methane in the mixture of biogas, hydrogen production rate,energy,exergyefficiences are increased. Moreover, increasing the molar ratio of carbon dioxide to methane in the biogas combination at hightemperatures, resulted a decrease in hydrogen production per mole of methane,so the energy,exergy efficiencies of the entiresystem (decreased). As well as the most energy,exergy efficiencies of the whole in the case of hydrogen production is maximum,achieved to 52%,42%, respectively.

In this paper, a novel multi-generation system based on gas turbine-modular helium reactor cycle is presented. Integrated system consists of a Gas turbine-modular helium reactor cycle as a base cycle and from the combination of subsystems, hydrogen production, absorption refrigeration cycle, and desalination system. Thermodynamic comprehensive modeling (energy and exergy) was done on the suggested system. The effect of various system parameters, such as turbine inlet temperature, compressor pressure ratio, carbon dioxide to methane molar ratio, vapor generator temperature, and mass flow rate of the desalination system have been evaluated on the overall performance of the system. Also, optimization of the overall system using single and multi-objective optimization method has been investigated in terms of energy and exergy compared to the base case. The results showed that the maximum net power output and the energy efficiency and exergy of the overall system in compressor pressure ratio between 2.3-2.45 were 275 MW, 72.05%, and 49.35%, respectively, and with increasing turbine inlet temperature, heat production rate and energy and exergy efficiencies of overall system increases and the cooling production rate and freshwater decreases. In addition, the optimal point of the mass flow ratio of the desalination system for the energy and exergy efficiencies of overall system is 2.857. According to the results obtained in the multi-objective optimization method, the energy and exergy efficiencies of overall system were 74.41% and 50.21%, respectively, and exergy destruction has been reduced to 0.74% compared to base case.