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The natural gas entering the liquefaction cycle usually consists of nitrogen, ethane, propane and also heavier hydrocarbons which are economically explainable to be separated from methane, considering that their heating values are higher than methane. In this paper, a hybrid system is developed and analyzed for liquefied natural gas, natural gas liquids and power tri-generation using LNG/NGLs recovery system, absorption–compression combined refrigeration, organic Rankine cycle and solar parabolic trough collectors. This integrated structure produces 54.12 kg s−1 NGLs, 66.52 kg s−1 LNG and 278.5 MW net power output. Specific power consumption, thermal and exergy efficiencies of the hybrid system are 0.3771 kWh kg−1 LNG, 78.38% and 84.47%, respectively. The pinch method is used to extract the heat exchanger network related to the multi-stream heat exchanger of the hybrid system. To simulate the integrated structure, MATLAB programming, HYSYS and TRNSYS software with the weather conditions of Bandar Abbas city in Iran are used. The effect of natural gas composition entering the cycle on system parameters is studied and reported. Results show that with the reduction in methane percentage in natural gas to 55 mol%, specific power consumption increases to 0.6004 kWh kg−1 LNG, and thermal efficiency decreases to 71.61%. The integrated structural behavior at different operating conditions is used to investigate the sensitivity analysis. [ABSTRACT FROM AUTHOR]

• A new configuration of power plant for Sabalan wellheads data is proposed. • Energy, exergy and exergoeconomic analyses are done. • A transcritical CO 2 and KCS11 is used to produce power from geothermal brines. • An algorithm for Pinch point analysis for heat exchangers is demonstrated. • Maximum net output power and minimum power specific cost have been improved. A new integrated cycle based on different real temperatures and pressures on Sabalan geothermal power plant, located in Iran, has been proposed and thermodynamic and exergoeconomic analyses are performed. The Kalina and Transcritical Rankine cycles are used as bottoming cycles and an algorithm are applied to find the exact location of the pinch points in heat exchangers. Also, a parametric study carried out to reveal the effects on the thermodynamic and exergoeconomic performance of the integrated cycle of such important parameters as separator 1 pressure, separator 2 pressure, pinch point temperature difference in the evaporators, higher pressure of the Kalina cycle and the ratio of the Transcritical cycle higher pressure to the critical pressure. Finally, the proposed cycle performance is optimized from the thermodynamic and exergoeconomic viewpoints. The results show that for the integrated geothermal power plant, the power generation, thermal efficiency, exergy efficiency and power specific cost rate are calculated to be 19,448 kW, 16.63%, 63.78%, and 4.521 $/GJ, respectively, which indicate that the proposed cycle has improved thermodynamically and exergoeconomically compared to previous studies. [ABSTRACT FROM AUTHOR]

• A novel integrated system for liquid hydrogen production is developed. • This system consists of the thermo-electrochemical and hydrogen liquefaction cycles. • Solar dish collectors are used for supplying the system required heat demand. • Pinch method on multi-stream exchangers to achieve heat exchanger networks is used. • The total thermal efficiency of the integrated system is 71.4% Hydrogen production and liquefaction using solar thermo-electrochemical water splitting systems can as an effective method for long-term renewable energy source storage are suggested. In this paper, a novel integrated configuration for the cogeneration of liquid hydrogen and oxygen by magnesium-chlorine thermo-electrochemical water splitting cycle, hydrogen liquefaction unit, and solar dish collectors is developed. The novel integrated structure produces 7116 kg/h liquid hydrogen and 57597 kg/h oxygen. Through the magnesium-chlorine cycle, pure hydrogen is produced and the required energy is supplied through solar renewable energy based on the climatic conditions of Isfahan city in Iran. Then the produced hydrogen enters the liquefaction process to generate liquid hydrogen. The heat and power consumption of the whole system for the cogeneration of liquid hydrogen and oxygen are 207.9 MW and 373.9 MW, respectively. The heat waste of the integrated structure is used to produce hot water as a by-product. The specific power consumption of the liquefaction cycle is 7.6 kWh/kg LH 2 and also the total thermal efficiency of the whole integrated system is 71.4%. Through the pinch method, heat exchanger networks related to multi-stream heat exchangers of the present system are extracted. Sensitivity analysis is used to investigate the effects of changes in major parameters including operating conditions of the thermo-electrochemical cycle as well as changes in the solar dish collector main parameters and the results are reported. [ABSTRACT FROM AUTHOR]

Heat integration and configuration optimization of a unique cycle based on biomass gasification are presented. The system provides heat, freshwater, and electricity to an area located in the southern part of Iran using the gasification of sugarcane bagasse. The main question to be responded is to find the optimum configuration which minimizes the total external utility consumption. It is assumed that 34500 kg/day of bagasse is available and the electricity, heating, and water demand of the area should be covered. It is concluded that the total utility consumption is 3113.69 kW if no heat integration is utilized. On the other hand, partial heat integration results in a total utility consumption of 590.93 kW. The least possible utility consumption which occurs in full heat integration condition is 214.6 kW. By increasing the gasification temperature from 900 °C to 915 °C, it is possible to enhance the integration by removing one of the heaters. The sensitivity analysis shows that the highest CHP efficiency occurs for a biomass flow rate of 32970 kg/day. It is concluded that energy integration techniques serve well in the identification of the optimum gasification temperature and biomass flow rate which lead to the minimum utility consumption and highest CHP efficiency. • Pinch analysis is used to find the optimum configuration with minimal utility consumption. • Utility consumption in partial integration is almost three times the utility consumption in full integration. • Biomass flow rate which lead to the highest CHP efficiency is determined. • Increasing the gasification temperature enhances the heat integration. • Power, heat, and water demand of an off-grid area can be met using the proposed system. [ABSTRACT FROM AUTHOR]