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Journal ArticleDOI: 10.1007/S10973-021-10607-7

Exergetic and economic evaluation of a novel integrated system for trigeneration of power, refrigeration and freshwater using energy recovery in natural gas pressure reduction stations

02 Mar 2021-Journal of Thermal Analysis and Calorimetry (Springer International Publishing)-Vol. 145, Iss: 3, pp 1467-1483
Abstract: Nowadays, with increasing energy consumption, global warming, and many problems caused by weather conditions, the tendency to use novel methods of energy generation with high efficiency and low cost that reduce environmental pollution has increased. This study investigates the feasibility of using gas pressure energy recovery in natural gas pressure reduction stations by turboexpanders for cogeneration of power and refrigeration. Turboexpanders and compression refrigeration cycles are employed to recover the energy from natural gas pressure reduction stations. Then, natural gas along with the compressed air enters the Brayton power generation cycle and its waste heat is used in the carbon dioxide (CO2) power generation plant, multistage Rankine cycle, and multi-effect thermal desalination unit. This integrated structure generates 105.6 MW of power, 2.960 MW of refrigeration, and 34.73 kg s−1 of freshwater. The electrical efficiencies of the Rankine power generation cycle, CO2 power generation plant, and the whole integrated structure are 0.4101, 0.4120, and 0.4704, respectively. The exergy efficiency and irreversibility of the developed integrated structure are 60.59% and 68.17 MW, respectively. The exergy analysis of the integrated structure shows that the highest rates of exergy destruction are related to the combustion chamber (59.68%), heat exchangers (14.70%), and compressors (14.46%). The annualized cost of the system (ACS) is used to evaluate the developed hybrid system. The economic analysis of the integrated structure indicated the period of return, the prime cost of the product, and capital cost are 2.565 years, 0.0430 US$ kWh−1, and 372.3 MMUS$, respectively. The results reveal that the period of return is highly sensitive to the electricity price, such that the period of return in the developed integrated structure is less than 5 years for the electricity price of 0.092 US$ kWh−1 and more. Also, the period of return is less than 5 years for the initial investment cost of 632.9 MMUS$ and less, which is economically viable.

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Topics: Cogeneration (62%), Exergy efficiency (59%), Waste heat (58%) ... show more
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6 results found


Journal ArticleDOI: 10.1007/S10973-021-10813-3
Abstract: The main purpose of this paper is to study the thermodynamic, economic, and environmental aspects of a integrated system combined cooling, heating, and power generation system empowered by biomass and natural gas. Eco-Indicator 99 method is utilized to quantify the environmental impact. The proposed system consists of four main subsystems producing power, heating, and cooling. Natural gas is mixed with the syngas to enhance its heating value. The results indicate that the exergy efficiency of system is 39.45%, the products cost per exergy unit is 9.71 $ h−1, and the products environmental impact per exergy unit is 4422 mpt GJ−1. Also, when the natural gas mass flow rate-to-syngas mass flow rate ratio increases from 0 to 0.5, the exergy efficiency is found to improve by 71.97%, whereas the products cost per exergy unit and environmental impact per exergy unit of total products are seen to decline by 70.75 and 64.09%, correspondingly. Additionally, the exergy efficiency enhances by 19.48%, while the cost and environmental impact per exergy unit of the total products drop by 13.39 and 13.02%, respectively, as the splitter separation ratio increases from 0 to1.

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Topics: Exergy efficiency (73%), Exergy (62%)

8 Citations


Journal ArticleDOI: 10.1007/S10973-021-10833-Z
Abstract: Industrial surplus heat is a great available source and because of potential for external use can create benefits for society and industry. Utilizing surplus heat can deliver a way to decrease the use of primary energy and to play a part in global CO2 mitigation. The potential of using excess heat in the main industrial CO2 capture and utilization plant of Iran is investigated. A CO2 liquefaction cycle i.e., ammonia-water absorption system is developed using the heat waste of the flue gas. Process modeling is developed in Aspen Hysys™ v.10 software with the aid of Peng-Robinson equation of state. Energy, exergy, economic and exergoeconomic analyses are then employed to evaluate the developed CO2 liquefaction cycle integrated into the carbon capture and utilization plant. Results of process design and simulation show that the developed CO2 liquefaction system can liquify CO2 with the capacity of 54.5 tons per day using the flue gas enthalpy. The developed CO2 liquefaction system has the COP of 0.28, and overall exergy efficiency of 69.7%. The highest amount of exergy is destructed in ammonia reboiler with the amount of 281.92 kW. Exergoeconomic results reveal that the compressors in CO2 compression unit along with ammonia absorber and stripper have the highest importance among equipment.

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Topics: Exergy efficiency (61%), Liquefaction (59%), Exergy (58%) ... show more

8 Citations


Journal ArticleDOI: 10.1007/S10973-021-10898-W
M. Nourpour1, M.H. Khoshgoftar Manesh1Institutions (1)
Abstract: Natural gas compressor stations have a significant potential for waste heat recovery. In this paper, a novel quadruple combined cycle has been proposed based on a turbocompressor gas station. In this regard, Serajeh gas station in Qom (Iran), including three 25 MW nominal gas turbines that each turbine provided power requirement for compressor, has been considered. Steam and organic Rankine cycles have been used to recover waste heat and generate more power, which uses exhaust gas turbines. Seven organic fluids have been examined. Energy, Exergy, Exergoeconomic, Exergoenvironment, Emergoeconomic, and Emergoenvironmental (6E) analyses have better understood the system from different perspectives. In this regard, computer code has been developed in MATLAB for 6E analysis. Verification of thermodynamic simulation of developed code has been compared with THERMOFLEX software and reference data with high accuracy. Also, sensitivity analysis was carried out based on main parameters. Advanced exergy-based analysis associated with endogenous/exogenous and avoidable/unavoidable parts has been performed for deep analysis of each component. The results show an increase of approximately 16% in the integrated cycle's thermal efficiency compared to gas turbines. The combustion chamber has the highest exergy destruction rate, and the LP superheater and economizer have the lowest exergy efficiency. R113 was selected as the best organic fluid from thermodynamic and R141b from an economic and environmental point of view. Cost rates and environmental impacts of the entire system will be approximately 3300 $ h−1 and 2038 pts h−1, respectively.

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Topics: Exergy efficiency (64%), Combined cycle (62%), Exergy (59%) ... show more

Journal ArticleDOI: 10.1016/J.JPOWSOUR.2021.230490
Abstract: This paper focuses on introducing a new configuration of a hybrid system for producing power and hydrogen together with pre-heating natural gas in PRSs. The configuration is based on regenerative Brayton, Rankine and proton exchange membrane electrolyzer cycles. Also, a heat exchanger is embedded for supplying the required heating load of NG pre-heating to prevent hydrate formation. A robust energy, exergy, and eco-environment mathematical model with real assumptions is developed to prove feasibility of the introduced system. To make the study applicable for different PRS capacities, the analyses are done for different equipment sizes during different months of year. The parametric study showed that design variables of the Brayton cycle and pressure of inlet NG are very effective parameters in the design of this proposal. Analyzing the results in different months illustrated that the best performance is achieved in January; so that, 20.25 MW of power, 19.91 MW of heating load, and 11.96 kg/h hydrogen are produced for the optimum equipment variables in this month. At these conditions, the first- and second-law efficiencies and the levelized total costs rate are respectively obtained as 58.91%, 34.02%, and 7.03 $/GJ. Also, the payback period is 6.77 years based on the NPV approach.

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Topics: Brayton cycle (59%), Exergy (55%), Degree Rankine (51%)

Open accessJournal ArticleDOI: 10.1007/S40095-021-00440-X
Abstract: In recent years, the use of Allam cycle based on the closed cycle of carbon dioxide has been considered by researchers due to its high efficiency and reduction of carbon dioxide emissions in the environment. In the present study, the combined system including Allam cycle and absorption cycle has been investigated from the perspective of energy, exergy and exergy–economy. The use of the absorption cycle is to use the waste heat of the power cycle and increase energy efficiency. The simulation results show that the total exergy efficiency of the cogeneration cycle is 0.72. Turbine, compressor and absorption cycle are introduced as primary components that should be considered from the exergy–economic point of view because they account for the highest cost rate of exergy efficiency. Also, the results of parametric analysis indicate that increasing the compressor pressure ratio has a negative effect on the cycle performance, thus reducing the overall work and efficiency of the exergy as well as increasing the cost rate. Similarly, changing the compressor pressure ratio has the greatest impact on the performance of the combined cycle, so that changing the pressure ratio in the range of 2 to 10 resulted in reducing the exergy efficiency by 63%. The key assessment is that the performance of the system increases as the temperature of the cooled water in the evaporator rises. Exergy efficiency works in contrast to the system performance coefficient and the main reason for the return of imperfections in the absorption cooling system is the undesirable heat transfer in the system heat exchangers.

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Topics: Exergy efficiency (74%), Exergy (62%), Combined cycle (58%) ... show more

References
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49 results found


Journal ArticleDOI: 10.1016/J.ENERGY.2013.12.060
01 Apr 2014-Energy
Abstract: The paper investigates the integration of renewable energy sources and water systems, presenting a novel solar system producing simultaneously: electrical energy, thermal energy, cooling energy and domestic water. Such system is designed for small communities in European Mediterranean countries, rich in renewable sources and poor in fossil fuels and water resources. The polygeneration system under analysis includes PVT (photovoltaic/thermal solar collectors), a MED (multi-effect distillation) system for SW (seawater) desalination, a single-stage LiBr–H2O ACH (absorption chiller) and additional components, such as storage tanks, AHs (auxiliary heaters) and BOP (balance of plant) devices. The PVT produces simultaneously electrical energy and thermal energy. The electrical energy is delivered to the grid, whereas the thermal energy may be used for space heating and/or domestic HW (hot water) production. As an alternative, the solar thermal energy can be used to drive an ACH, producing CHW (chilled water) for space cooling. Finally, the solar energy, in combination with the thermal energy produced by an auxiliary biomass-fired heater, may be used by the MED system to convert SW into potable water. The system is dynamically simulated by means of a zero-dimensional transient simulation model. A thermo-economic analysis is also presented, aiming at determining the optimal values of the most important design variables.

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143 Citations


Journal ArticleDOI: 10.1016/J.APPLTHERMALENG.2016.08.197
Hossein Nami1, S.M.S. Mahmoudi1, Arash Nemati1Institutions (1)
Abstract: Exergoeconomic and exergoenvironmental analyses are reported for a novel cogeneration system including a gas turbine, a heat recovery steam generator, a supercritical carbon dioxide recompression Brayton cycle and an organic Rankine cycle. A comprehensive parametric study is carried out to clarify the effects of some decision parameters on the exergoeconomic performance of the proposed system. Also, the payback period is determined for the proposed system. The sum of capital investment cost, total exergy destruction cost and environmental impact cost is considered as an objective function which is optimized with respect to the decision parameters. The variation in overall exergoeconomic factor is determined and its implication to the system design is discussed. It is observed that under the optimized condition the average product unit cost of the system (cost of produced power and steam) is decreased by 0.56 $/GJ when compared to the value obtained under a base condition.

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Topics: Organic Rankine cycle (59%), Cogeneration (57%), Heat recovery steam generator (57%) ... show more

124 Citations


Journal ArticleDOI: 10.1016/J.RSER.2017.04.019
Abstract: Currently, the use of renewable energies is put on the agenda of most researchers in the field of energy. On the other hand, in many parts of the world, fossil fuel power plants continue to be the main source of electrical power. Increased efficiency of fossil fuel power plants and the use of solar energy lead to recommendation of merging solar farms with the cycle of these power plants. The statistics indicate that the output of fossil fuel power plants in Iran, which currently supply about 93.9% of electricity of the national network, is experiencing a negative growth. On the other hand, according to government plans, part of the generated electricity should be provided from renewable energy sources in the next few years. In this paper, the use of solar energy for integration with power-plant units of Isfahan is investigated. To do this, preheat project of the feed water is investigated on 7 separate scenarios. The results showed that replacing all high-pressure feed water preheaters with solar farm increases the net energy and exergy efficiencies of the power plant by 18.3% compared to the simple cycle which respectively reaches to 45% and 43.91%. Given the importance of reducing emissions of CO 2 pollutants at power plants, reduction level of gas emissions, as well as some economic aspects of the integration of solar farm with the cycle of this power plant has also been evaluated.

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Topics: Renewable energy (69%), Power station (66%), Energy development (65%) ... show more

94 Citations


Journal ArticleDOI: 10.1016/J.DESAL.2006.01.010
Yongqing Wang1, Noam Lior2Institutions (2)
05 Sep 2006-Desalination
Abstract: Humidified gas turbines (HGT) have been identified as a promising way of producing power. The use of the steam-injected gas turbine (STIG) HGT cycle in a combined power and water desalination system was analyzed using energy and exergy performance criteria. A brief description and rationale of the background of HGT cycles and dual-purpose power and water systems is given. A thermal desalination unit was modeled and analyzed, and the results led to the selection of a multi-effect thermal vapor compression (METVC) unit for producing fresh water from seawater for both general use and humidification; then the performance of a STIG-based combined system was investigated. The analysis performed improved the understanding of the combined STIG power and water desalination process and of ways to improve and optimize it. Some specific conclusions are that: (1) a METVC desalination system is preferred to a multieffect evaporation one when the pressure of the motive steam is high enough, >∼3 bar, to run a steam jet ejector; (2) the steam injection rate in the STIG cycle has a strong effect on water and power production, offering good flexibility for design and operation; (3) higher pressure ratios and higher steam injection rates in the STIG cycle increase power generation, but decrease water production rates, and higher turbine inlet temperatures increased both power and water production; (4) a distinct water production gain can be obtained by recovering the stack gas energy. The results indicate that such dual-purpose systems have good synergy, not only in fuel utilization, but also in operation and design flexibility.

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72 Citations


Journal ArticleDOI: 10.1016/J.DESAL.2011.10.028
31 Jan 2012-Desalination
Abstract: There are a large number of gas turbine power plants in the south of Iran that could be exploited to produce fresh water and overcome water shortage. In order to combine gas turbine power plant and thermal desalination, heat recovery steam generator (HRSG) is required for producing steam. Few papers in literature have investigated this combination and none of them has considered HRSG in their studies. Thus, in this paper, multi-effect evaporation thermal vapor compression desalination (ME-TVC) is coupled to gas turbine plant through HRSG. After performing a thorough thermoecnomic analysis, an optimization study is done in view of three approaches. The first and second approaches are single objective optimizations, which utilize two heuristic algorithms, namely, genetic algorithm (GA) and particle swarm optimization (PSO). The first approach is a global optimization problem, which completely optimize the combined system. The second one, as an innovative method, is a local optimization approach, which optimize HRSG and ME-TVC in two separate stages while the third approach is a multi objective optimization. Eventually, the results of the first and second approaches show that the minimum amount of objective function achieved by PSO is better, although the third approach presents a system with higher productivity.

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72 Citations