Single-pressure Heat Recovery Steam Generator Research Articles

Comprehensive analysis of energy, exergy, economic, and environmental aspects in implementing the Kalina cycle for waste heat recovery from a gas turbine cycle coupled with a steam generator

This study introduces a transformative approach by integrating the Kalina Cycle System (KCS) within a cogeneration of heat and power (CHP) framework alongside a gas turbine (GT) cycle and a single-pressure heat recovery steam generator (HRSG). Through development of thermodynamic and thermo-economic models, a comprehensive assessment of the system's performance is conducted, emphasizing energy, exergy, and exergoeconomic considerations. The outcomes reveal a remarkable enhancement in both 1st and 2nd law efficiencies for the GT-HRSG/KCS-11 system compared to its conventional counterpart. Witnessing an ascent from 53.60 % to 54.31 % in efficiency and an increase from 50.59 % to 51.27 % in 2nd law efficiency underscores the profound impact of the proposed system. Furthermore, a parametric study scrutinizes the influence of diverse design parameters on critical objective functions, encompassing second law efficiencies and the total system cost rate. Findings spotlight the combustion chamber, heat recovery steam generator, and gas turbine as focal points of exergy destruction, revealing crucial insights for system optimization. The combustion chamber, heat recovery steam generator, and gas turbine emerge as pivotal contributors to the total cost rate, highlighting key areas for economic consideration. According to the results, the share of the environmental cost rates in the system cost rate is insignificant.

Novel hybrid solar tower-gas turbine combined power cycles using supercritical carbon dioxide bottoming cycles

In this study, two novel hybrid solar power tower-gas turbine combined power cycles are proposed, in which two supercritical CO2 (s-CO2) power cycles connected in series are driven by waste energy from a gas turbine cycle partially driven by a solar power tower. The solar power tower system provides a high-temperature thermal energy up to 1223 K. Each of the two novel schemes consists of a combined cycle with configuration 1 combining an s-CO2 recompression cycle and an s-CO2 recuperative cycle as bottoming cycles. Configuration 2 replaces the recompression cycle with an s-CO2 partial cooling cycle. Another objective is to evaluate the suitability of the two novel configurations against two conventional combined cycles including a bottoming steam Rankine cycle driven by a single-pressure heat recovery steam generator (HRSG) and dual-pressure HRSG. A thermodynamic and economic analysis is conducted for the plants, all sized at 50 MWe, and found that while configuration 1 has the lowest overall cycle efficiency of 0.4608, it exhibits the lowest levelized cost of electricity (LCOE) of $83.16/MWh, due to its compact components. The highest overall cycle efficiency of 0.5066 is obtained for the configuration that employs a bottoming steam Rankine cycle with dual-pressure HRSG, which exhibits an LCOE of $85.08/MWh. Transient analysis of the cycle configuration 1 further highlighted a high solar share over 0.652 during the month of June. A sensitivity analysis examined the effect of the maximum and minimum pressures and the compressor inlet temperature of the two bottoming s-CO2 cycles, and design direct normal irradiance (DNI) on power plant performance, required field size, and LCOE. The lowest LCOE of $80.90/MWh for configuration 1 is realized when the compressor inlet temperatures approach 308 K for both s-CO2 cycles. Increasing the design DNI levels corresponds to a significant decrease in LCOE but results in lower solar shares.

Thermodynamic Study of Multi Pressure HRSG in Gas/Steam Combined Cycle Power Plant

Combined cycle power plants have a combination of gas based topping cycle and steam based bottoming cycle through the use of Heat Recovery Steam Generator (HRSG). These HRSG may be either of single pressure (SP) or dual pressure (DP) or multiple pressure type. Here in this study thermodynamic analysis is carried out for optimal performance of HRSG using different types of HRSG layout for combined cycle efficiency improvement. Performance of single pressure HRSG and dual pressure HRSG, utilized in gas/steam combined cycle is analyzed and presented here. In comparison to single pressure, dual pressure HRSG offers 10 to 15% higher reduction in stack temperature due to greater heat recovery and thus improved plant efficiency.

Thermodynamic and thermoeconomic optimization of an integrated gas turbine and organic Rankine cycle

A multi objective optimization method is conducted for a cogeneration system to achieve the best system design parameters from both thermodynamic and economic aspects by utilizing NSGA-II (non-dominated sorting genetic algorithm-II). Exergy efficiency and total cost rate of the system have been considered as objective functions. The cogeneration system consists of a gas turbine and an ORC (organic Rankine cycle) in which the two cycles are connected through a single-pressure HRSG (heat recovery steam generator). In order to optimize the system, air compressor pressure ratio, isentropic efficiencies of air compressor and gas turbine, air preheater outlet temperature, turbine inlet temperature, Pinch point temperatures of HRSG and evaporator, condenser and evaporator temperatures are selected as decision variables. Optimization results indicate that exergy efficiency of the cycle increases from 51.4% at base case to 56.15% at the optimized condition while more than 12.98% reduction is achieved in the total cost rate of the system. Also, by applying multi-objective optimization method, the exergo-economic factor has reached from 10.68 to 28.54 suggesting that optimum system is achievable when the system costs are due to the investment costs. Furthermore, it is found that the gas turbine inlet temperature has important role on the trade-off between exergy efficiency and cost criteria.

Comprehensive analysis of energy, exergy and exergo-economic of cogeneration of heat and power in a combined gas turbine and organic Rankine cycle

Organic Rankine cycles (ORCs) are appropriate technology for the conversion of low quality thermal energy to electrical power. Meanwhile the waste heat from the exhaust gases of the top cycle of the energy conversion systems to the environment is prevented. The aim of this work is thermodynamic, exergo-economic and environmental assessment of a cogeneration of heat and power cycle (CHP), considering the three objective functions of first and second law efficiencies and the total cost rates of the system. The proposed combined heat and power cycle combines a gas turbine (GT) and an ORC through a single-pressure heat recovery steam generator (HRSG). In this regard, after the thermodynamic simulation of the cycle, validations of the results of top and bottom cycles are evaluated using the works available in the literature. The results show that the most exergy destruction rate takes place in the combustion chamber, and after that in heat recovery steam generator and gas turbine, respectively. The exergo-economic factor for the whole cycle is 10.59% indicating that the exergy destruction cost rate is more than capital investment cost rate. In order to assess the effects of design parameters on the objective functions, a parametric study is conducted. The results reveal that the increase in pressure ratio and isentropic efficiency of air compressor and gas turbine efficiency improves thermodynamic performance of the system, however, the more increase of these parameters deteriorates the total cost rates. Furthermore, the increase in air preheater exiting temperature will be useful for the system both in terms of thermodynamic and exergo-economic. The increase in the condensation temperature and pinch point temperature difference of evaporator of ORC and increase in pinch point temperature difference of heat recovery steam generator cause the first and second law efficiency to fall down and also to increase the total cost rates of the system.

Thermodynamic and economic analysis of a gas turbine combined cycle plant with oxy-combustion

Abstract This paper presents a gas turbine combined cycle plant with oxy-combustion and carbon dioxide capture. A gas turbine part of the unit with the operating parameters is presented. The methodology and results of optimization by the means of a genetic algorithm for the steam parts in three variants of the plant are shown. The variants of the plant differ by the heat recovery steam generator (HRSG) construction: the singlepressure HRSG (1P), the double-pressure HRSG with reheating (2PR), and the triple-pressure HRSG with reheating (3PR). For obtained results in all variants an economic evaluation was performed. The break-even prices of electricity were determined and the sensitivity analysis to the most significant economic factors were performed.

The Effects of Parameters on HRSG Thermodynamic Performance

Changes of inlet temperature, mass flow rate and composition of flue gas, or of water/steam pressure and temperature in heat recovery steam generator (HRSG), all will modify the amount of waste heat recovered from flue gas; this brings forward a desire for the optimization of the design of HRSG. For single pressure HRSGs with given structures and specified values of inlet temperature, mass flow rate and composition of flue gas, the steam mass flow rate and gas outlet temperature of the HRSG are analyzed as functions of several parameters. This analysis is based on the laws of thermodynamics, incorporated into the energy balance equations for the heat exchangers. Those parameters are superheated steam pressure and temperature, feedwater temperature and pinch point temperature difference. It was shown that the gas outlet temperature could be lowered by selecting appropriate water/steam parameters and pinch point temperature difference. While operating with the suggested parameters, the HRSG can generate more high-quality steam, a fact of great significance for waste heat recovery from wider ranges of sources for better energy conservation.

Exergy and Energy Analysis of Combined Cycle systems with Different Bottoming Cycle Configurations

SUMMARY The paper deals with thermodynamic analysis of cooled gas turbine-based gas-steam combined cycle with single, dual, or triple pressure bottoming cycle configuration. The cooled gas turbine analyzed here uses air as blade coolant. Component-wise non-dimensionalized exergy destruction of the bottoming cycle has been quantified with the objective to identify the major sources of exergy destruction. The mass of steam generated in different configurations of heat recovery steam generator (HRSG) depends upon the number of steam pressure drums, desired pressure level, and steam temperature. For the selected set of operating parameters, maximum steam has been observed to be generated in the case of triple pressure HRSG = 19 kg/kg and minimum in single pressure HRSG = 17.25 kg/kg. Plant-efficiency and plant-specific works are both highest for triple-pressure bottoming cycle combined cycle. Non-dimensionalized exergy destruction in HRSG is least at 0.9% for B3P, whereas 1.23% for B2P, and highest at 3.2% for B1P illustrating that process irreversibility is least in the case of B3P and highest in B1P. Copyright © 2012 John Wiley & Sons, Ltd.

Combined Cycle Power Plant Performance Analyses Based on the Single-Pressure and Multipressure Heat Recovery Steam Generator

AbstractIn this study sensitivity analysis is performed for single, double-pressure, and triple-pressure heat recovery steam generators in a combined cycle power plant. Steam pressure, evaporator pinch point, and economizer approach temperature differences are taken as design parameters. Temperature-heat (T-Q) graphics of heat recovery steam generator (HRSG) designs and the effects of design parameters to the plant efficiency, net power production, and heat transfer areas are obtained. The calculated results are useful to compare single and multipressure HRSGs in a combined cycle power plant scheme. In single-pressure, double-pressure, and triple-pressure HRSG, net power increment is approximately 0.05, 0.28, and 0.29% at every 10-bar inlet pressure increment. The net power output of the cycle decreases with increasing evaporator pinch point temperature difference. For single-pressure HRSG, this decrement is approximately 0.54%, whereas for double-pressure and triple-pressure HRSG it is approximately 0.21...

Typical off-design analytical performances of internal combustion engine cogeneration

Based on experimental data, typical off-design characteristic curves with corresponding formulas of internal combustion engine (ICE) are summarized and investigated. In combination with analytical solution of single-pressure heat recovery steam generator (HRSG) and influence of ambient pressure on combined heat and power (CHP) system, off-design operation regularities of ICE cogeneration are analyzed. The approach temperature difference ΔTa, relative steam production and superheated steam temperature decrease with the decrease in engine load. The total energy efficiency, equivalent exergy efficiency and economic exergy efficiency first increase and then decrease. Therefore, there exists an optimum value, corresponding to ICE best efficiency operating condition. It is worth emphasizing that ΔTa is likely to be negative in low load condition with high design steam parameter and low ICE design exhaust gas temperature. Compared with single shaft gas turbine cogeneration, ΔTa in ICE cogeneration is more likely to be negative. The main reason for this is that the gas turbine has an increased exhaust gas flow with the decrease in load; while ICE is on the contrary. Moreover, ICE power output and efficiency decrease with the decrease in ambient pressure. Hence, approach temperature difference, relative steam production and superheated steam temperature decrease rapidly while the cogeneration efficiencies decrease slightly. It is necessary to consider the influence of ambient conditions, especially the optimization of ICE performances at different places, on cogeneration performances.

Analysis of Dynamic Behavior of a Heat Recovery Steam Generator and Steam Turbine System

The dynamic behavior of a single-pressure heat recovery steam generator and turbine system for the combined cycle power plant is simulated on the basis of one-dimensional unsteady governing equations. A water level control and a turbine power control are also included in the calculation routine. Transient response of the system to the variation of gas turbine exit condition is simulated and effect of the turbine power control on the system response is examined. In addition, the effect of the treatment of inertia terms(fluid inertia and thermal inertia of heat exchanger metal) on the simulated transient response is investigated.

The effect of gas turbine coolant modulation on the part load performance of combined cycle plants. Part 2: Combined cycle plant

For combined cycle plants that consist of heavy-duty gas turbine and single-pressure heat recovery steam generator, the effect of gas turbine coolant modulation on plant performance is analysed. Two distinct schemes for gas turbine load control are adopted (the fuel-only control and the variable compressor geometry control), based on the gas turbine calculation in Part 1 of this series of papers. Models for heat recovery steam generator and steam turbine are combined with the gas turbine models of Part 1 to result in a complete analysis routine for combined cycles. The purpose of gas turbine coolant modulation is to minimize coolant consumption by maintaining the turbine blade temperatures as high as possible. It is found that the coolant modulation leads to reduction in heat recovery capacity, which decreases steam cycle power. However, since the benefit of coolant modulation for the gas turbine cycle is large enough, the combine cycle efficiency is improved.