Regenerative Gas Turbine Cycle Research Articles

Thermodynamic and economic analysis of the combined cooling, heating, and power system coupled with the constant-pressure compressed air energy storage

Combined cooling, heating, and power (CCHP) technology represents a widely adopted and promising approach for achieving high energy efficiency. However, the conventional operational mode of electricity determined by heating often leads to poor partial load efficiency, strong heat-electricity coupling, and inflexible regulation in the gas turbine system. This paper proposes a novel CCHP system coupling the gas turbine and constant-pressure compressed air energy storage. Thermodynamic and economic models are built to evaluate the four schemes of the coupled system based on the simple cycle or regenerative cycle gas turbine with a 10 MW power output, respectively. The results show that different coupling methods offer advantages in various aspects. The coupled scheme employing the simple cycle gas turbine and the ejector demonstrates the highest primary energy ratio of 68.94 %. Meanwhile, the coupled scheme using the regenerative cycle gas turbine and expander exhibits superior economic performance, with the fuel cost output rate and system profit reaching 1.426 and $734.43, respectively. Integrating constant-pressure compressed air energy storage effectively widens the heat-electricity ratio adjustment range of the gas turbine CCHP system. Among them, the coupled scheme employing the regenerative cycle gas turbine and ejector achieves the highest relative variation rate of the heat-electricity ratio, reaching 13.68 %.

Effect of regenerative effectiveness on the performance of simple gas turbine

The deregulation of the power and energy sector introduced a strong element of competition. Power plant operators try to develop techniques to maximize profits in the dynamic power industry. New methods of improving and optimizing simple gas turbine power plants are needed to enhance operational decision making and therefore to maximize power plant profitability by reducing operational and maintenance cost and increasing revenue. In this work, the thermodynamic model equations of both a simple gas turbine and regenerative gas turbine cycle were used to analyses the effect of increase in the regenerative effectiveness to the performance of the simple gas turbine. Microsoft Excel 2010 software was used to carried out the analysis. It was observed that for the simple gas turbine the thermal efficiency, heat rate, specific fuel consumption and heat addition have a constant value of 35.4%, 9630Btu/Kwh, 0.2768kg/Kwh, 44237.8Kw, all through, while for the regenerative gas turbine cycle as the value of the regenerative effectiveness increases from 0.8 to 1.0, the thermal efficiency increases from 41.1% to 65.0%, the heat rate decreases from 8753Btu/Kwh to 5536 Btu/Kwh , specific fuel consumption decreases from 0.248945122Kg/Kw.h to 0.157432413 Kg/Kw.h and heat addition reduces from 39782.5Kw to 25158.4Kw. It was seen clearly that the regenerative gas turbine cycle has higher thermal efficiency compare to the simple gas turbine, and as the regenerative effectiveness of the regenerative gas turbine cycle increases the performance of the regenerative gas turbine increases.

Thermodynamic analysis of combined cycle system based on supercritical CO2 cycle and gas turbine with reheat and recuperation

ABSTRACT The gas turbine combined cycle (GTCC) system has the advantages of high power density, high efficiency, and fast start-stop control, which will occupy an important position in the next-generation power system. In this paper, two groups of reheat cycle gas turbines with different thermal parameters are compared and the reheat and recuperative cycle is constructed by adding a recuperator to the recommended reheat cycle. Two typical sCO2 cycles are selected to construct a combined cycle system with simple cycle, reheat cycle, reheat, and recuperative cycle, respectively. In the range of gas turbine pressure ratio of 32–56, the parameters of GTCC with turbine inlet temperature of 1750°C are optimized based on the system calculation method of total physical properties, and the thermodynamic performance of the GTCC system was evaluated. The research shows that the reheat cycle with a TRIT (inlet temperature of the turbine after reheat) of 1250°C has higher efficiency and lower specific net work than the reheat cycle with a TRIT of 1750°C, and the relatively low exhaust temperature is more suitable for the sCO2 bottoming cycle. In addition, compared with the simple cycle, the optimal topping cycle thermal efficiency of the reheat and regenerative cycle is only reduced by 0.1%, but the exhaust temperature is higher. Under the same sCO2 cycle form, the combined cycle efficiency is improved by 1.5–2.0%. The thermal efficiency of the reheat and regenerative cycle gas turbine combined cycle (RCRHCC) studied in this paper can reach up to 67.53%, which has the potential to become the next generation of GTCC units.

NUMERICAL APPROACH FOR ENERGY ANALYSIS OF GT POWER PLANT

Gas turbine (GT) power plants are of major interest because of their power capacity and lower investment. However, engineers and researchers still struggle in order to maximize their energy-economic efficiency and reduce their greenhouse gas emissions. These targets were formerly simulated using numerical integration, and uncommonly are tackled experimentally. In this work, a numerical analytical model has been established emphasizing the effect of pressure ratio on simple and regenerative gas turbine cycle performance which is successively used in the energy and exergy analysis of the power system. The elaborated analytical model permits a simple and quick calculation of maximum power output and efficiency based on pressure ratio and turbine inlet temperature using a direct and exact equation which can generate a rapid calculation for specific parameters. These equations will be helpful for designers and industrialists. The established analytical calculation is validated against some numerical examples and available data, and the agreement is observed to be fairly acceptable for such a universal and quite simple analytical model.

Comparison between biogas and pure methane as the fuel of a polygeneration system including a regenerative gas turbine cycle and partial cooling supercritical CO2 Brayton cycle: 4E analysis and tri-objective optimization

The present study aims at utilizing the waste energy from a regenerative gas turbine cycle (GTC) for the production of hydrogen in a proton exchange membrane electrolysis unit (PEMEU), freshwater in a reverse osmosis desalination unit (RODU), and hot steam in a heat recovery steam generator (HRSG). The waste heat of the GTC is first recuperated in a partial cooling supercritical CO2 Brayton cycle (SCBC) to supply the required electricity for the PEMEU and RODU. Then, the residual heat is recuperated in the HRSG to produce hot steam. The waste heat of the SCBC is recovered by two thermoelectric generators in the heat dissipation stages of the cycle. The system is assessed and optimized from thermodynamic, economic, and environmental aspects for the two cases of utilizing methane and biogas as fuel. The optimization results indicate that biogas is superior from an economic aspect as the unit cost of polygeneration and economic cost rate in the case of biogas are 32.5% lower than the case of methane as fuel. On the other hand, employing methane as the fuel brings about lower environmental impacts as it causes a 29% lower environmental cost rate than the case of biogas as fuel. There is quite a narrow difference between the exergy efficiency of the two cases from 40.45% in the case of biogas to 40.72% in the case of methane as fuel. Moreover, the heat loss recovery of the GTC ameliorates the exergy efficiency by 11.96% points in the biogas case.

Optimal operation of a multi-generation district energy hub based on electrical, heating, and cooling demands and hydrogen production

In this study, a new configuration of a multi-generation energy system is proposed based on waste heat recovery from a regenerative gas turbine cycle (as the driver cycle) for running a district heating heat exchanger, a Rankine cycle, an ejector refrigeration cycle, and a proton exchange membrane electrolyzer cycle. In the first phase of the study, a thorough parametric model of the system is developed in EES software based on the eco-exergy and enviro-exergy analyses. The second phase is focused on the optimal operation of the system utilizing a robust multi-criteria optimization in Matlab software. Results of the parametric study showed that: (i) the share of fuel, capital, and environmental penalty costs rates in the system's total cost rate are respectively 46.95%, 29.38%, and 23.67%, at the optimal conditions. (ii) although the design variables of the bottoming cycles are not effective on the amount of pollutants, they have a significant effect on the enviro-exergy assessment criterion. The optimal system productions are included 21.42 MW of power, 26.81 MW of heat, 8.89 MW of cold, and 11.96 kg/h of hydrogen. The energy and exergy efficiencies are found to be 89.75% 35.21%, respectively. In such conditions, the payback period is approximately 5 years, demonstrating the economic feasibility of the proposal. Recovering the waste heat of conventional cycles to develop an energy production hub with minimal energy loss is one of the most important challenges in the energy matrix and relying on the results of the present study, it can be concluded that the proposed system has done this task well.

Combined effect of variable parameters on the performance of gas turbine cycles

The gas turbine cycle is the key solution for the power generation system from the last decade. several types of research are going to enhance the overall system efficiency of the gas turbine cycle. In the present study, six sets have been investigated parametrically for energy and exergy. Thermodynamic assessments have been effectively achieved for the compressor pressure ratio from 4 to 14, turbine inlet temperature (TIT) from 1000K to 1500K, and ambient temperature 250C to 450C. Results show that for every 100 rises in ambient temperature the maximum decrease in peak output and peak thermal efficiency is 6.2% and 5% respectively at 1000K and 3.6% and 1.9% respectively at 1500K. The exergy loss by exhaust gases of set 4 and set 5 increased by 107% whereas set 6 is decreased by 85.5% as compared to set 1 under the conditions when the exergy loss by exhaust gases of set 1 is minimum at TIT 1000K. The total exergy destruction of set 3, set 4, set 5, and set 6 is increased by 102%, 32.6%, 133.3%, and 102% respectively as compared to set 1 under the conditions when the total exergy destruction of set1 is minimum at TIT 1000K. Regenerative Gas Turbine cycle is the best in terms of the ratio of net output to exergy destruction of the plant as well as initial, operational, and maintenance costs.

Techno-economic and techno-environmental assessment and multi-objective optimization of a new CCHP system based on waste heat recovery from regenerative Brayton cycle

This investigation aims to present thermo-environmental and thermo-economic parametric studies for a new hybrid tri-generation energy system. In system, a regenerative gas turbine cycle (RGTC) is the runner system, while Kalina cycle (KC) and ejector refrigeration cycle (ERC) are considered as companion elements. The parametric study is done through validated computational program developed in EES software. Two new functions of levelized total annual emissions and costs (LTAE and LTAC), with two conventional indices of energetic and exergetic efficiencies (ηen and ηex) are defined for system evaluation. Thermodynamics modeling revealed that almost 75 % of total exergy destruction is related to the RGTC. The outputs of parametric study prove that pressure ratio of compressor and pinch-point temperature of heat exchanger 2 are the most and least effective parameters, respectively. Also, for the bottoming cycles, changes in KC design parameters resulted in creation of peak points in all the evaluation criteria; but changes in the ERC design parameters resulted in uniform (ascending or descending) behavior in the evaluation criteria. The NSGA-II optimization procedure (using MATLAB software) results in ηen,opt = 77.17 %, ηex,opt = 38.94 %, LTAEopt = 9.36 kg/kW.yr, and LTACopt = 106.04 €/kW.yr. The payback period and net present value of the tri-generation system are found as 3.74 yr and 1184525.43 €.

Waste heat recovery of a combined regenerative gas turbine - recompression supercritical CO2 Brayton cycle driven by a hybrid solar-biomass heat source for multi-generation purpose: 4E analysis and parametric study

This study substantiates that the waste heat of a combined regenerative gas turbine cycle (GTC) and recompression supercritical CO2 Brayton cycle (SCBC) driven by a hybrid solar-biomass heat source can be effectively recovered via combining various subsystems encompassing a thermoelectric generator, an LiBr–H2O absorption refrigeration system, a heat recovery steam generator, and a proton exchange membrane electrolyzer with the cycle. The environmental and exergoeconomic performances of the system under a base case are compared between a hybrid solar-biomass mode (with direct normal irradiance (DNI) of 0.8 kW m−2) and biomass-only mode (while DNI is lower than 0.4 kW m−2). The results indicate that the employment of the solar power tower results in slight reductions in environmental impacts, while significant diminutions in thermodynamic and economic performances. For hybrid and biomass-only modes, the total energy efficiency of the system correspondingly improves by 22.48 and 29.6% points and the total exergy efficiency of the system respectively enhances by 6.18 and 7.6% points thanks to recovering the waste energy from the regenerative GTC - recompression SCBC via the proposed systems, while the utilized subsystems in the two mentioned modes respectively account for merely 5.1% and 8.1% of the system total cost rate.

Energetic and Exergetic Investigation of Regenerative Gas Turbine Air-Bottoming/Steam -Bottoming Combined Cycle

The present study is a thermodynamic analysis of a Regenerative Air-Bottoming combined (RABC) cycle /Steam bottoming combined (RABC) cycle operated by the exhaust gases the topping gas turbine cycle. The fractional mass of exhaust gases passes through the first heat exchanger where it exchanges heat with the compressed air from the air compressor of topping cycle and remaining amount of exhaust gasses passes through a second heat exchanger where it uses to supply heat to RABC cycle or third heat exchanger where it uses to supply heat to RSBC cycle. The energetic and exergetic performance of RABC cycle and RSBC cycle is investigated using turbine inlet temperature (1000 K⩽ TIT⩽1500 K) and mass fraction of exhaust gas (0⩽x⩽1) of the topping cycle as the input variables. The work net output attained its peak value at x=0 which is 22.1 % to 27.3 % for RABC cycle and 22.7 % to 21.5 % for RSBC cycle whereas the maximum thermal efficiency and minimum specific fuel consumption is observed at x=1. Also exergy loss by exhaust gases is minimum at x=0 for both RABC cycle and RSBC cycle. Finally, it is concluded that for the maximum work net output and minimum exergy loss by exhaust gases, RABC cycle is the best option followed by RSBC cycle but for optimum thermal efficiency and minimum specific fuel consumption purely regenerative gas turbine cycle have no comparison with RABC cycle and RSBC cycle.

Energy and exergy analysis of biogas fired regenerative gas turbine cycle with CO2 recirculation for oxy-fuel combustion power generation

In this paper, thermodynamic performance of oxy-biogas regenerative gas turbine cycle with CO2 recirculation is evaluated. The CO2 stream is split into the primary and dilution zones. In the primary zone, chemical-equilibrium-model is applied for exergy analysis. Influences of relevant parameters—CO2-to-O2 molar ratio (CtO) in the primary zone and primary diluent ratio (PDR)—on the temperature of combustion chamber (CC) and turbine, net produced power, thermal efficiency, specific fuel consumption (SFC) and CO2 capturing mass flow rate are studied. Decreasing CtO and raising PDR result in high net produced power. Thermal efficiency has a maximum value in the range of CtO (1.5<CtO<4.0) and PDR (0.2<PDR<0.6) and by enhancing CtO, exergy destruction diminishes in both zones. With increasing the CtO in the range of 1.5–2.98, thermal efficiency is increased by 9.92% while variation of CtO in the range of 2.98–4 results in reduction of thermal efficiency by 1.3%. In the range of PDR, the minimum value of SFC is 388 g/kWh and in the range of CtO, the lowest achievable SFC is 387.4 g/kWh. Additionally, dilution zone exergy destruction and CC exergy efficiency increases with PDR and CtO. The two-zone model provided an appropriate control on the turbine inlet temperature.

Performance investigation of a novel hybrid system for simultaneous production of cooling, heating, and electricity

A novel hybrid system (a regenerative gas turbine cycle with a heat exchanger integrated with Kalina and ejector refrigeration cycles) is developed for the simultaneous production of cooling, heating, and electricity. The laws of thermodynamics are applied to investigate the system performance from energetic and exergetic standpoints. A parametric study is presented for studying the effects of some key parameters on four criteria of electrical efficiency (ηelec), thermal efficiency (ηth), primary energy ratio (PER), and exergetic efficiency (ηex). The key parameters include compressor pressure ratio, gas turbine inlet temperature, ammonia mass fraction in basic ammonia/water mixture, vapor generator pressure, the pinch-point temperature difference of the heat exchanger (which connects Kalina and ejector sub-cycles), and evaporator temperature. Results of the modeling procedure at the base conditions areηelec = 37.87%, ηth=36.55%, PER=74.42% andηex = 38.85%; also, the produced cooling, heating, and power are 164.7 kW, 836.85 kW, and 1038 kW, respectively. The combustion chamber and evaporator has also the highest and lowest contribution in total exergy destruction (with exergy destruction rates of 939.2 kW and 0.034 kW), respectively. The parametric study shows that compressor pressure ratio and heat exchanger pinch-point temperature difference have the highest and lowest impacts on the performance criteria, respectively.

Exergoeconomic and environmental analyses of a novel multi-generation system including five subsystems for efficient waste heat recovery of a regenerative gas turbine cycle with hybridization of solar power tower and biomass gasifier

This study aims to recover the waste heat from a previously introduced regenerative gas turbine cycle (GTC) when it is driven by a hybrid heat source composed of solar power tower (SPT) and biomass gasification. The system consists of electricity, cooling, heating, and hydrogen production subsystems. Therefore, the system is converted into a novel multi-generation system which is examined through energy, exergy, exergoeconomic, and environmental analyses. In the proposed system, to recover the waste energy of a topping GTC, a steam Rankine cycle (SRC) by employing a thermoelectric generator (TEG) instead of a conventional condenser, a domestic hot water heat exchanger (DHWHX), and an LiCl-H2O absorption refrigeration system (ARS) are utilized. The power recovered by the TEG is employed to produce hydrogen by a proton exchange membrane (PEM) electrolyzer. In the base case, the proposed system with the multi-generation exergy efficiency of 43.11%, can produce 98.2 MW of electricity which 24.7 MW of this production is owing to the waste heat recovery of GTC in SRC. Heating, cooling, and hydrogen production rates are 13 MW, 10.5 MW, and 4.1 kg/h, respectively. Due to the waste heat recovery of GTC, total exergy efficiency is increased by 9.04 percentage points. The total cost rate of the proposed system is 7799 $/h, and the unit cost of multi-generation is 8.26 $/GJ. Although the increase of direct normal irradiance (DNI) brings about a slight drop in the thermodynamic performance of the system, it improves the performance of the system from economic and environmental standpoints. By increasing the number of mirrors, which induces the reduction of fuel consumption and improvement of the environmental performance of the system, it is accompanied by weakening the performance of the system from thermodynamic and economic perspectives. By raising the pressure ratio of the GTC compressor, the heating production rate declines and the performance of the system decreases from economic and environmental aspects, while the net power output and multi-generation exergy efficiency have their maximum values at pressure ratios of 14.6 and 11.2, respectively. The only positive effect of increasing the pinch temperature difference of heat recovery steam generator (HRSG) is that it can significantly increase the heating production rate.

Design and multi-criteria optimisation of a trigeneration district energy system based on gas turbine, Kalina, and ejector cycles: Exergoeconomic and exergoenvironmental evaluation

A novel trigeneration district energy system (TDES) is designed and evaluated from energy, exergy, exergoeconomic, and exergoenvironmental points-of-view. By recovering the wasted heat of a regenerative gas turbine cycle, a heat exchanger is utilized for heating applications, a Kalina cycle is run for generating some additional power, and an ejector refrigeration cycle is used for producing some cold. The problem is firstly modeled through developing a precise code in Engineering Equation Solver program and then optimal conditions are sought by coupling the outputs of modeling procedure with Artificial Neural Network, and Non-dominated Sorting Genetic Algorithm II approaches. Three new functions of integrated weighted efficiency, exergoeconomic criterion, and exergoenvironmental criterion are defined as the system’s evaluation criteria. From a robust parametric study, it is demonstrated that the system’s evaluation criteria have the highest and lowest sensitivity on the variation of pressure ratio of compressor and pinch-point temperature difference of heat exchanger 2, respectively. From the optimisation procedure, the optimum values of the system’s primary energy ratio, exergetic efficiency, exergoeconomic criterion, and exergoenvironmental criterion are 76.9%, 30.8%, 58.4 $/GJ, and 42.7 kg/GJ, respectively. At these conditions, the capacity of the TDES is 1025.9 kW, 1642.3 kW, and 304.9 kW with the associated cost of production of 149.6 $/GJ, 7.8 $/GJ, and 60.1 $/GJ for power, heat, and cold, respectively.

Energy and Exergy Analyses of Regenerative Gas Turbine Air-Bottoming Combined Cycle: Optimum Performance

The current paper presents a thermodynamic analysis of an air-bottoming cycle (ABC) operated by the exhaust gasses of a regenerative gas turbine cycle. The partial exhaust heat of a topping gas turbine cycle is utilized to heat the compressed air of the ABC by passing it through a heat exchanger (H.E.2), whereas remaining heat is used to heat the compressed air of the topping cycle before entering a combustion chamber by passing it through a heat exchanger (H.E.1). The effects of the turbine inlet temperature of the topping cycle (1000 K ⩽ $${\text{TIT}}$$ ⩽ 1500 K) and fraction of mass flow rate of the exhaust gas (0 ⩽ $$x$$ ⩽ 1) on the net output, combined thermal efficiency, exergy destruction, exergy loss by exhaust gasses, and specific fuel consumption (SFC) are investigated parametrically for a particular value of the pressure ratio of the topping and bottoming cycles. At $$x = 0$$ , the net output and thermal efficiency of the combined cycle increase by 15.1% and 31.3%, respectively, whereas the SFC decreases by 13.1% and 15.5% at $${\text{TIT}} = 1000\;{\text{K}}$$ and $${\text{TIT}} = 1500\;{\text{K}}$$ , respectively. The exergy destruction of the heat exchanger of the topping cycle increases, whereas that of the bottoming cycle decreases with an increase in x. Overall, in terms of the net output and thermal efficiency, a simple gas turbine cycle with an air-bottoming combined cycle performs better than a simple regenerative gas turbine cycle; however, in view of the exergy loss by exhaust gasses, a simple regenerative gas turbine cycle is better than the combined cycle.

Comprehensive techno-economic and environmental sensitivity analysis and multi-objective optimization of a novel heat and power system for natural gas city gate stations

In the present study, a novel combined heat and power system is proposed to use in natural gas city gate stations. The proposed cogeneration system is used for power generation and satisfying heating requirements of the natural gas preheating in city gate stations. The system is composed of a regenerative gas turbine cycle, a heat exchanger and a Kalina cycle integrated with a city gate station heater. A comprehensive sensitivity analysis and single- and multi-objective optimizations are applied to investigate the system performance. The analysis is based on energetic, exergetic, environmental and economic standpoints which includes all important effective parameters (compressor presser ratio rCom, gas turbine inlet temperature TGT, ammonia base concentration XNH3, condenser pinch point temperature difference ΔTPP,Con, ambient temperature Tamb and inlet NG pressure PNG,in). Also, in addition to the energetic and exergetic efficiencies, a new performance criterion is defined as the system’s annual costs to incomes ratio (this new function covers economic and environmental criteria simultaneously). The outputs of sensitivity analysis reveal that, rCom affects significantly on all of the three performance criteria; also, Tamb and PNG,in has the most impact on energetic efficiency. The exergetic analysis at the base system conditions shows that the combustion chamber has the maximum contribution in total exergy destruction with a share of 54.96%. This share is reduced by 3.65% in multi-objective optimization mode. Also, comparing the outputs of the base system and the multi-objective optimization mode for the proposed cogeneration system represents 30.72%, 3.48% and 10.55% improvement in energetic efficiency, exergetic efficiency and system’s annual costs to incomes ratio, respectively.

New approach for enhancing the performance of gas turbine cycle: A comparative study

Abstract In order to achieve higher performance of combined cycle power plant and reducing greenhouse gas emission, recently different technical approaches have been used based on the choice of higher efficiency of pure mechanical components nonetheless these solution remain very expensive. Though, including original combinations of two or more systems are not well treated previously. In this paper a comparative study has been performed for three combined gas turbine cycle configurations S3, S4 and S5 including innovative combinations for both simple gas turbine cycle S1 and regenerative gas turbine cycle S2. The evaluations of these proposed configurations are executed according to the thermodynamics conventional energy and exergy analysis. The effects of the new configurations on the performance and the exergy destruction of the combined cycle plant are investigated. The results indicate that the third configuration S5 is the most beneficial for the industrialists. The analysis method is used to recognize and identify the most substantial system configuration with less exergy destruction. Models that were used in the present study give a novel alternative approach to increases not only the thermal efficiency and net output of power plant by using the same amount of fuel rate but also to reduce exergy losses.

A comprehensive study of simple and recuperative gas turbine cycles with inlet fogging and overspray

Ambient temperature has an adverse effect on gas turbine performance. This problem could be overcome through air cooling technologies such as evaporative cooling, fogging, mechanical cooling, absorption chillers, and thermal energy storage. Therefore, this article aims to evaluate the performance of simple and regenerative gas turbine cycles at dry and wet compression cases. A numerical model was constructed for this purpose then the model was validated for dry cycle conditions with an existing turbine SULZER S3 performance data. An inlet fogging was used to full saturate the inlet air and overspray was used for decreasing the compressor inlet temperature at various ambient temperatures. The results showed that the inlet fogging and overspray reduce the compressor work up to 12%. The results also showed that the thermal efficiency was improved with using the inlet fogging and by increasing the overspray rate. The highest thermal efficiency of 44% was achieved when overspray 3% with recuperation was applied. It can be concluded from this work that the specific fuel consumption is reduced significantly and the output power increases, increasing the thermal efficiency when using the recuperator combined with the wet compression and the overspray.

Thermodynamic, environmental and economic performance optimization of simple, regenerative, STIG and RSTIG gas turbine cycles

Regeneration and steam injection are both well proven as well as promising modifications which can boost power, increase thermal efficiency, part load performance and limit NOx emissions. However, their benefits are still largely unexploited. To investigate these modifications, a comprehensive but practical model is established as an essential improvement on the air standard models. Our multipronged modeling approach enables simultaneous monitoring and optimization of thermodynamic, economic and environmental performance. Additionally, it provides a more accurate analysis by using specifically calculated thermodynamic properties, precisely calculated adiabatic flame temperature, a realistic definition of regenerator effectiveness coefficient and updated cost parameters. Simulating this improved model, a detailed parametrical analysis of steam injected and regenerative gas turbine cycles is performed for varying pressure, steam injection and equivalence ratios. Optimal operating parameters are investigated considering the state of the art cycle parameters and component efficiencies along with non-equilibrium NOx and CO emissions. Contradictory traits of steam injection and regeneration as well as their combinations are presented and comparatively discussed. Conditions of maximum economic profit are demonstrated regarding the up-to-date equipment cost data and escalations in fuel prices. We suggest, this study will contribute to optimization of novel and future gas turbine designs and applications.

Thermodynamic and Energy Study of a Regenerator in Gas Turbine Cycle and Optimization of Performances

In this paper, thermodynamic study of simple and regenerative gas turbine cycles is exhibited. Firstly, thermodynamic models for both cycles are defined; thermal efficiencies of both cycles are determined, the overall heat transfer coefficient through the heat exchanger is calculated in order to determinate its performances and parametric study is carried out to investigate the effects of compressor inlet temperature, turbine inlet temperature and compressor pressure ratio on the parameters that measure cycles' performance. Subsequently, numerical optimization is established through EES software to determinate operating conditions. The results of parametric study have shown a significant impact of operating parameters on the performance of the cycle. According to this study, the regeneration technique improves the thermal efficiency by 10%. The studied regenerator has an important effectiveness (˜ 82%) which improves the heat transfer exchange; also a high compressor pressure ratio and an important combustion temperature can increase thermal efficiency.