This paper briefs the configuration and performance of large size gas turbines and their composed combined cycle power plants designed and produced by four large renown gas turbine manufacturing firms in the world, pr...This paper briefs the configuration and performance of large size gas turbines and their composed combined cycle power plants designed and produced by four large renown gas turbine manufacturing firms in the world, providing reference for the relevant sectors and enterprises in importing advanced gas turbines and technologies.展开更多
The equilibrium hydrate formation conditions for CO2/H2 gas mixtures with different CO2 concentrations in 0.29 mol% TBAB aqueous solution are firstly measured.The results illustrate that the equilibrium hydrate format...The equilibrium hydrate formation conditions for CO2/H2 gas mixtures with different CO2 concentrations in 0.29 mol% TBAB aqueous solution are firstly measured.The results illustrate that the equilibrium hydrate formation pressure increases remarkably with the decrease of CO2 concentration in the gas mixture.Based on the phase equilibrium data,a three stages hydrate CO2 separation from integrated gasification combined cycle （IGCC） synthesis gas is investigated.Because the separation efficiency is quite low for the third hydrate separation,a hybrid CO2 separation process of two hydrate stages in conjunction with one chemical absorption process （absorption with MEA） is proposed and studied.The experimental results show H2 concentration in the final residual gas released from the three stages hydrate CO2 separation process was approximately 95.0 mol% while that released from the hybrid CO2 separation process was approximately 99.4 mol%.Thus,the hybrid process is possible to be a promising technology for the industrial application in the future.展开更多
Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produc...Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produced from capturing the pressure energy has been calculated. Based on the comprehensive thermodynamic analysis, two systems have been proposed to capture pressure energy of natural gas to generate electricity. In this study, the expression of exergy is given which can be used in evaluating purposes. A problem with this multidisciplinary study is the complicated boundary condition. In conclusion, a technical prospect on recoverable natural gas pressure energy has been presented based on total energy system theory.展开更多
This paper presents the improved design of a 25 MW gas turbine power plant at Omoku in the Niger Delta area of Nigeria, using combined cycle application. It entails retrofitting a steam bottoming plant to the existing...This paper presents the improved design of a 25 MW gas turbine power plant at Omoku in the Niger Delta area of Nigeria, using combined cycle application. It entails retrofitting a steam bottoming plant to the existing 25 MW gas turbine plant by incorporating a heat recovery steam generator. The focus is to improve performance as well as reduction in total emission to the environment. Direct data collection was performed from the HMI monitoring screen, log books and manufacturer’s manual. Employing the application of MATLAB, the thermodynamics equations were modeled and appropriate parameters of the various components of the steam turbine power plant were determined. The results show that the combined cycle system had a total power output of 37.9 MW, made up of 25.0 MW from the gas turbine power plant and 12.9 MW (an increase of about 51%) from the steam turbine plant, having an HRSG, condenser and feed pump capacities of 42.46 MW, 29.61 MW and 1.76 MW respectively. The condenser cooling water parameters include a mass flow of 1180.42 kg/s, inlet and outlet temperatures of 29.8°C and 35.8°C respectively. The cycle efficiency of the dry mode gas turbine was 26.6% whereas, after modification, the combined cycle power plant overall efficiency is 48.8% (about 84% increases). Hence, SIEMENS steam turbine product of MODEL: SST-150 was recommended as the steam bottoming plant. Also the work reveals that a heat flow of about 42.46 MW which was otherwise being wasted in the exhaust gas of the 25 MW gas turbine power plant could be converted to 12.9 MW of electric power, thus reducing the total emission to the environment.展开更多
The main objective of this investigation is to obtain an optimum value for the flue gas recirculation ratio in a 620 MW-Natural Gas Combined Cycle (NGCC) power plant with a 100% excess air in order to have a compositi...The main objective of this investigation is to obtain an optimum value for the flue gas recirculation ratio in a 620 MW-Natural Gas Combined Cycle (NGCC) power plant with a 100% excess air in order to have a composition of the exhaust gas suitable for an effective absorption by amine solutions. To reach this goal, the recirculated flue gas is added to the secondary air (dilution air) used for cooling the turbine. The originality of this work is that the optimum value of a Flue Gas Recirculation (FGR) ratio of 0.42 is obtained from the change of the slope related to the effects of flue gas recirculation ratio on the molar percentage of oxygen in the exhaust gas. Compared to the NGCC power plant without flue gas recirculation, the molar percentage of carbon dioxide in the flue gas increases from 5% to 9.2% and the molar percentage of oxygen decreases from 10.9% to 3.5%. Since energy efficiency is the key parameter of energy conversion systems, the impact of the flue gas recirculation on the different energy inputs and outputs and the overall efficiency of the power plant are also investigated. It is found the positive effects of the flue gas recirculation on the electricity produced by the steam turbine generator (STG) are more important than its cooling effects on the power output of the combustion turbine generator (CTG). The flue gas recirculation has no effects on the water pump of the steam cycle and the increase of energy consumed by the compressor of flue gas is compensated by the decrease of energy consumed by the compressor of fresh air. Based on the Low heating value (LHV) of the natural gas, the flue gas recirculation increases the overall efficiency of the power plant by 1.1% from 57.5% from to 58.2%.展开更多
The objective of this investigation is to analyze the impact of the flue gas recirculation (FGR) ratio on the different energy inputs and outputs of a SNGCC power plant as well as its overall efficiency. Simulation re...The objective of this investigation is to analyze the impact of the flue gas recirculation (FGR) ratio on the different energy inputs and outputs of a SNGCC power plant as well as its overall efficiency. Simulation results indicate that increasing flue gas recirculation increases the energy consumed by the recirculation compressor and the energy produced by the gas turbine. On the other hand, it decreases the production of energy of the steam turbine and the energy consumed by the pump of the steam cycle. The overall energy efficiency of the SNGCC power plant is highest (41.09%) at a value of 0.20 of the flue gas recirculation. However, the flue gas composition with a FGR ratio of 0.37 is more suitable for effective absorption of carbon dioxide by amine solutions. Based on the low heating value (LHV) of hydrogen, the corresponding overall efficiency of the power plant is 39.18% and the net power output of the plant is 1273 kW for consumption of 97.5 kg/hr. of hydrogen.展开更多
A numerical calculation of a 3000MWt MHD steam combined cycle system with tail gasification is described . The research scheme has been set up and the parameters of this system have been designed. Then the efficiency ...A numerical calculation of a 3000MWt MHD steam combined cycle system with tail gasification is described . The research scheme has been set up and the parameters of this system have been designed. Then the efficiency of the combined cycle system has been calculated which is up to 53.9%.展开更多
Exhaust gas recirculation control(EGRC),an inlet air heating technology,can be utilized in combination with inlet/variable guide vane control(IGV/VGVC) and fuel flow control(FFC) to regulate the load,thereby effective...Exhaust gas recirculation control(EGRC),an inlet air heating technology,can be utilized in combination with inlet/variable guide vane control(IGV/VGVC) and fuel flow control(FFC) to regulate the load,thereby effectively improving the part-load(i.e.,off-design) performance of the gas turbine combined cycle(GTCC).In this study,the E-,F-,and H-Class EGR-GTCC design and off-design system models were established and validated to perform a comparative analysis of the part-load performance under the EGR-IGV-FFC and conventional IGV-FFC strategies in the E/F/H-Class GTCC.Results show that EGR-IGV-FFC has considerable potential for the part-load performance enhancement and can show a higher combined cycle efficiency than IGV-FFC in the E-,F-,and H-Class GTCCs.However,the part-load performance improvement in the corresponding GTCC was weakened for the higher class of the gas turbine because of the narrower load range of EGR action and the deterioration of the gas turbine performance.Furthermore,EGR-IGV-FFC was inferior to IGV-FFC in improving the performance at loads below 50% for the H-Class GTCC.The results obtained in this paper could help guide the application of EGR-IGV-FFC to enhance the part-load performance of various classes of GTCC systems.展开更多
In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energ^^ of liquefied natural gas （LNG） could be fully utilized as well. A system...In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energ^^ of liquefied natural gas （LNG） could be fully utilized as well. A system simulation and ther^nodynamic analysis were carried out, the Kalina cycle was reorganized by changing the concentration of “basic composition”, so that a better thermal matching in the heat exchanger could be obtained and the irreversibility of the system was decreased. It was found that the Kalina cycle generally used in the bottom of combined power cycle could also be used to recover the cold energy of LNG. The results show that the exergy efficiency of 42.97% is obtained. Compared with the previous system attained the exergy efficiency of 39.76%, the improved system has a better performance.展开更多
Forecasts of the various types of gas turbines economics and performance of gas turbine combined cycle （GTCC） with will help power plant designers to select the best type of gas turbine for future Chinese powerplant...Forecasts of the various types of gas turbines economics and performance of gas turbine combined cycle （GTCC） with will help power plant designers to select the best type of gas turbine for future Chinese powerplants. The cost and performance of various designs were estimated using the commercial software GT PRO. Improved GTCC output will increase the system efficiency which may induce total investment and will certainly increase the cumulative cash which then will induce the cost and the payback period. The relative annual fuel output increases almost in proportion to the relative GTCC output. China should select the gas turbine that provides the most economical output according to its specific conditions. The analysis shows that a GTCC power plant with a medium-sized 100 to 200 MW output gas turbine is the most suitable for Chinese investors.展开更多
After long-term operation,the performance of components in the GTCC system deteriorates and requires timely maintenance.Due to the inability to directly measure the degree of component malfunction,it is necessary to u...After long-term operation,the performance of components in the GTCC system deteriorates and requires timely maintenance.Due to the inability to directly measure the degree of component malfunction,it is necessary to use advanced exergy analysis diagnosis methods to characterize the components’health condition(degree of malfunction)through operation data of the GTCC system.The dissipative temperature is used to describe the degree of malfunction of different components in the GTCC system,and an advanced exergy analysis diagnostic method is used to establish a database of overall operating condition component malfunctions in theGTCC system.Ebsilon software is used to simulate the critical parameters of the malfunctions of the GTCC system components and to obtain the changes in the dissipative temperature of different components.Meanwhile,the fuel consumption and economic changes of the GTCC system on a characteristic power supply day under health and malfunction conditions are analyzed.Finally,the effects of maintenance costs,electricity,and gas prices on maintenance expenses and profits are analyzed.The results show that the GTCC system maintenance profit is 6.07$/MWh,while the GTCC system maintenance expense is 5.83$/MWh.Compared with the planned maintenancemode,the malfunction maintenance mode saves 0.24$/MWh.Simultaneously,the maintenance coefficient of GTCC should be adjusted under different malfunctions to obtain a more accurate maintenance period.展开更多
Maintenance scheduling and asset management practices play an important role in power systems,specifically in power generating plants.This paper presents a novel riskbased framework for a criticality assessment of pla...Maintenance scheduling and asset management practices play an important role in power systems,specifically in power generating plants.This paper presents a novel riskbased framework for a criticality assessment of plant components as a means to conduct more focused maintenance activities.Critical components in power plants that influence overall system performance are identified by quantifying their failure impact on system reliability,electric safety,cost,and the environment.Prioritization of plant components according to the proposed risk-based method ensures that the most effective and techno-economic investment decisions are implemented.This,in turn,helps to initiate modern maintenance approaches,such as reliability-centered maintenance(RCM).The proposed method is applied to a real combined cycle power plant(CCPP)in Iran,composed of two gas turbine power plants(GTPP)and one steam turbine power plant(STPP).The results demonstrate the practicality and applicability of the presented approach in real world practices.展开更多
The most difficult problem in hot gas desulfurization in Integrated Coal Gasification Combined Cycle （IGCC） is the pulverization of sulfur removal sorbents.Appropriate binders for hot gas sulfur removal sorbents can...The most difficult problem in hot gas desulfurization in Integrated Coal Gasification Combined Cycle （IGCC） is the pulverization of sulfur removal sorbents.Appropriate binders for hot gas sulfur removal sorbents can solve the pulverization problem.In this paper,six sorbents with binders of different argillaceous minerals were prepared by mechanical mixing method.Desulfurization behavior for hot gas desulfurization sorbents was investigated in a fixed-bed reactor.Result showed that sorbent NTKW2 with binder of clay had a better sulfidation performance.NTKW2 had a more stable performance than other sorbents in the continuous sulfidation-regeneration cycles.Sulfur capacity of sorbent remained the same in each cycle.The desulfurization efficiency and mechanical strength of NTKW2 were the best among the tested sorbents.The behavior of NTKW2 at different temperatures showed different performances,and the best reaction temperature was 550 ℃.Higher heat stability,sulfur capacity and desulfurization efficiency were found on NTKW2 in six continuous sulfidation-regeneration cycles.展开更多
Two Zn-based sorbents, L-991 and L-992 used for hot gas desulfurization (HGD) were introduced. Zn/Ti ratio of the two sorbent was 1:1 and 2:3 resptively and a certain proportion of Cu and Mn metal oxide were added int...Two Zn-based sorbents, L-991 and L-992 used for hot gas desulfurization (HGD) were introduced. Zn/Ti ratio of the two sorbent was 1:1 and 2:3 resptively and a certain proportion of Cu and Mn metal oxide were added into L-992, which provided better performance than L-991 in aspects of suitable work temperature, sulfur capacity and agglomeration on the surface of sorbent particles. The evaluation tests were done on both sorbents include multi cycles tests. ARD and SEM analysis were done on fresh and post tests sorbent. During continuous sulfidation/regeneration, the H2S concentra- tion can be reduced from about 10 g/m3 to less than 20 mg/m3, the H2S removal effi- ciency >99 %.展开更多
Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit w...Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit with coal water slurry gasifier was simulated and calculated using THERMOFLEX software, and the relations of oxygen coal ratio (Roc), water coal ratio (Rsc), gasification pressure, gasification temperature and cold gas efficiency were mostly researched. The results show that Roc and Rsc have effect of mutual restriction on gasification temperature, cold gas efficiency and syngas composition. Gasification pressure mainly determines the capacity of the gasifier, little effects on syngas composition.展开更多
Carbon capture and storage （CCS） technology will play a critical role in reducing anthropogenic carbondioxide （CO2） emission from fossil-fired power plants and other energy-intensive processes. However, theincreme...Carbon capture and storage （CCS） technology will play a critical role in reducing anthropogenic carbondioxide （CO2） emission from fossil-fired power plants and other energy-intensive processes. However, theincrement of energy cost caused by equipping a carbon capture process is the main barrier to its commer-cial deployment. To reduce the capital and operating costs of carbon capture, great efforts have been madeto achieve optimal design and operation through process modeling, simulation, and optimization. Accuratemodels form an essential foundation for this purpose. This paper presents a study on developing a moreaccurate rate-based model in Aspen Plus for the monoethanolamine （MEA）-based carbon capture processby multistage model validations. The modeling framework for this process was established first. The steady-state process model was then developed and validated at three stages, which included a thermodynamicmodel, physical properties calculations, and a process model at the pilot plant scale, covering a wide rangeof pressures, temperatures, and CO2 loadings. The calculation correlations of liquid density and interfacialarea were updated by coding Fortran subroutines in Aspen Plus. The validation results show that the cor-relation combination for the thermodynamic model used in this study has higher accuracy than those ofthree other key publications and the model prediction of the process model has a good agreement with thepilot plant experimental data. A case study was carried out for carbon capture from a 250 MWe combinedcycle gas turbine （CCGT） power plant. Shorter packing height and lower specific duty were achieved usingthis accurate model.展开更多
The objective of the first part of the investigation was to use Aspen Plus software and the Redlich-Kwong-Soave equation of state in order to simulate an adiabatic methanation reactor for the production of synthetic n...The objective of the first part of the investigation was to use Aspen Plus software and the Redlich-Kwong-Soave equation of state in order to simulate an adiabatic methanation reactor for the production of synthetic natural methane (SNG) using 1 kg/hr<span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">of carbon dioxide. In this paper, we define the Synthetic Natural Gas Combined Cycle (SNGCC) as a combined cycle power plant where the fuel is synthetic natural gas (SNG) produced by a methanation reactor. The feed of the methanation reactor is the recycled stream of carbon dioxide of a CO<sub>2</sub> capture unit treating the flue gas of the SNGCC power plant. The objective of the second part of the investigation is the utilization of Aspen plus software with SRK equation of state for the simulation of the SNGCC power plant. The metallurgical limitation of the gas turbine was fixed at 1300<sup><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°<span style="font-family:Verdana;white-space:normal;"></span></span></sup></span></span>C in this investigation. For effective absorption by amine solutions, the molar percentage of CO<sub>2</sub> in the flue gas should be higher than 10%. Moreover, in order to reduce technical problems linked to oxidative degradation of amine in the CO<sub>2</sub> capture plant, the percentage of O<sub>2</sub> in the flue gas should also be lower than 5%. To reach this goal, the primary air for combustion has 10% excess air (compared to stoichiometric air) and 37% of the flue </span><span style="font-family:Verdana;">gas leaving the SNGCC is recirculated as the secondary air for cooling the</span><span style="font-family:Verdana;"> turbine</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> As a result, the concentration of CO<sub>2</sub> and O<sub>2</sub></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of the flue gas entering the CO<sub>2</sub> capture unit were respectively equal to 10.2% and 2.01%. The simulation results of the SNGCC power plant indicate that 6.6 MJ of electricity are produced for each kg of carbon dioxide recycled from the CO<sub>2</sub> capture unit of the power plant. In other terms, the production of the 24.88 kg/hr</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of synthetic natural gas (SNG) consumes 62.36 kg/hr</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of recycled carbon dioxide and 16.4 kg/hr</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of hydrogen. The SNG produced by the methanation reactor of the power plant generates 114 kW of electricity. It is assumed in this paper that the hydrogen needed for the methanation of carbon dioxide is a product of a catalytic reforming plant that produces gasoline from heavy naphta fraction of an atmospheric distillation unit of crude oil.</span></span></span>展开更多
There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainabili...There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainability of this income is questionable. Energy problems started to appear, and can be intensified in coming years due to continuous growth of energy demands and consumptions. The demands already consume all produced Natural Gas (NG) in all GCC, except Qatar;and the NG is the needed fuel for Electric Power (EP) production. These countries have to import NG to run their EP plants. Fuel oil production can be locally consumed within two to three decades if the current rate of consumed energy prevails. The returns from selling the oil and natural gas are the main income to most of the GCC. While NG and oil can be used in EP plants, NG is cheaper, cleaner, and has less negative effects on the environment than fuel oil. Moreover, oil has much better usage than being burned in steam generators of steam power plants or combustion chambers of gas turbines. Introducing renewable energy or nuclear energy may be a necessity for the GCC to keep the flow of their main income from exporting oil. This paper reviews the GCC productions and consumptions of the prime energy (fuel oil and NG) and their role in electric power production. The paper shows that, NG should be the only fossil fuel used to run the power plants in the GCC. It also shows that the all GCC except Qatar, have to import NG. They should diversify the prime energy used in power plants;and consider alternative energy such as nuclear and renewable energy, (solar and wind) energy.展开更多
Qatar energy consumptions are among the highest in the world, and can easily serve double the present population. Energy conservation is a must, as the energy resources are finite, and their consumptions are increasin...Qatar energy consumptions are among the highest in the world, and can easily serve double the present population. Energy conservation is a must, as the energy resources are finite, and their consumptions are increasing at alarming rates. The country depends on desalted seawater, which consumes extensive amounts of energy, and is produced by using the least energy efficient desalting system. The desalination process is vulnerable to many factors, and strategic water storage needs to be built. The high energy consumptions are ruining the air and marine environments. Several suggestions are introduced to conserve energy in the Cogeneration Power Desalting Plants (CPDP), by moving to replace the Multi Stage Flash (MSF) desalting system by the energy efficient Seawater Reverse Osmosis System (SWRO);fully utilizing the installed power capacity to desalt water in winter, when electric power load is low, and during summer non-peak hours for strategic water storage;and modifying the simple Gas Turbines (GT) Power cycle plants to GT combined cycle to raise the Electric Power (EP) generation efficiency (to about 50%).展开更多
Airbreathing aero-engines are regarded as excellent propulsion devices from ground takeoff to hypersonic flight,and require control systems to ensure their efficient and safe operation.Therefore,the present paper aims...Airbreathing aero-engines are regarded as excellent propulsion devices from ground takeoff to hypersonic flight,and require control systems to ensure their efficient and safe operation.Therefore,the present paper aims to provide a summary report of recent research progress on airbreathing aero-engine control to help researchers working on this topic.First,five control problems of airbreathing aero-engines are classified:uncertainty problem,multiobjective and multivariable control,fault-tolerant control,distributed control system,and airframe/propulsion integrated control system.Subsequently,the research progress of aircraft gas turbine engine modelling,linear control,nonlinear control,and intelligent control is reviewed,and the advantages and disadvantages of various advanced control algorithms in aircraft gas turbine engines is discussed.Third,several typical hypersonic flight tests are investigated,and the modelling and control issues of dual-mode scramjet are examined.Fourth,modelling,mode transition control and thrust pinch control for turbine-based combined cycle engines are introduced.Followed,significant hypersonic airframe/propulsion integrated system control is analysed.Finally,the study provides specific control research topics that require attention on airbreathing aero-engines.展开更多
文摘This paper briefs the configuration and performance of large size gas turbines and their composed combined cycle power plants designed and produced by four large renown gas turbine manufacturing firms in the world, providing reference for the relevant sectors and enterprises in importing advanced gas turbines and technologies.
基金supported by the National Natural Science Foundation of China (51076155)Science & Technology Program of Guangdong Province(2009B050600006)
文摘The equilibrium hydrate formation conditions for CO2/H2 gas mixtures with different CO2 concentrations in 0.29 mol% TBAB aqueous solution are firstly measured.The results illustrate that the equilibrium hydrate formation pressure increases remarkably with the decrease of CO2 concentration in the gas mixture.Based on the phase equilibrium data,a three stages hydrate CO2 separation from integrated gasification combined cycle （IGCC） synthesis gas is investigated.Because the separation efficiency is quite low for the third hydrate separation,a hybrid CO2 separation process of two hydrate stages in conjunction with one chemical absorption process （absorption with MEA） is proposed and studied.The experimental results show H2 concentration in the final residual gas released from the three stages hydrate CO2 separation process was approximately 95.0 mol% while that released from the hybrid CO2 separation process was approximately 99.4 mol%.Thus,the hybrid process is possible to be a promising technology for the industrial application in the future.
基金Supported by Tianjin Institute of Urban Construction(03046)
文摘Current research and ways of capturing mechanical energy are discussed in this paper. By the aid of the comprehensive thermodynamic analysis and Aspen simulation tool, the amount of a vailable work that can be produced from capturing the pressure energy has been calculated. Based on the comprehensive thermodynamic analysis, two systems have been proposed to capture pressure energy of natural gas to generate electricity. In this study, the expression of exergy is given which can be used in evaluating purposes. A problem with this multidisciplinary study is the complicated boundary condition. In conclusion, a technical prospect on recoverable natural gas pressure energy has been presented based on total energy system theory.
文摘This paper presents the improved design of a 25 MW gas turbine power plant at Omoku in the Niger Delta area of Nigeria, using combined cycle application. It entails retrofitting a steam bottoming plant to the existing 25 MW gas turbine plant by incorporating a heat recovery steam generator. The focus is to improve performance as well as reduction in total emission to the environment. Direct data collection was performed from the HMI monitoring screen, log books and manufacturer’s manual. Employing the application of MATLAB, the thermodynamics equations were modeled and appropriate parameters of the various components of the steam turbine power plant were determined. The results show that the combined cycle system had a total power output of 37.9 MW, made up of 25.0 MW from the gas turbine power plant and 12.9 MW (an increase of about 51%) from the steam turbine plant, having an HRSG, condenser and feed pump capacities of 42.46 MW, 29.61 MW and 1.76 MW respectively. The condenser cooling water parameters include a mass flow of 1180.42 kg/s, inlet and outlet temperatures of 29.8°C and 35.8°C respectively. The cycle efficiency of the dry mode gas turbine was 26.6% whereas, after modification, the combined cycle power plant overall efficiency is 48.8% (about 84% increases). Hence, SIEMENS steam turbine product of MODEL: SST-150 was recommended as the steam bottoming plant. Also the work reveals that a heat flow of about 42.46 MW which was otherwise being wasted in the exhaust gas of the 25 MW gas turbine power plant could be converted to 12.9 MW of electric power, thus reducing the total emission to the environment.
文摘The main objective of this investigation is to obtain an optimum value for the flue gas recirculation ratio in a 620 MW-Natural Gas Combined Cycle (NGCC) power plant with a 100% excess air in order to have a composition of the exhaust gas suitable for an effective absorption by amine solutions. To reach this goal, the recirculated flue gas is added to the secondary air (dilution air) used for cooling the turbine. The originality of this work is that the optimum value of a Flue Gas Recirculation (FGR) ratio of 0.42 is obtained from the change of the slope related to the effects of flue gas recirculation ratio on the molar percentage of oxygen in the exhaust gas. Compared to the NGCC power plant without flue gas recirculation, the molar percentage of carbon dioxide in the flue gas increases from 5% to 9.2% and the molar percentage of oxygen decreases from 10.9% to 3.5%. Since energy efficiency is the key parameter of energy conversion systems, the impact of the flue gas recirculation on the different energy inputs and outputs and the overall efficiency of the power plant are also investigated. It is found the positive effects of the flue gas recirculation on the electricity produced by the steam turbine generator (STG) are more important than its cooling effects on the power output of the combustion turbine generator (CTG). The flue gas recirculation has no effects on the water pump of the steam cycle and the increase of energy consumed by the compressor of flue gas is compensated by the decrease of energy consumed by the compressor of fresh air. Based on the Low heating value (LHV) of the natural gas, the flue gas recirculation increases the overall efficiency of the power plant by 1.1% from 57.5% from to 58.2%.
文摘The objective of this investigation is to analyze the impact of the flue gas recirculation (FGR) ratio on the different energy inputs and outputs of a SNGCC power plant as well as its overall efficiency. Simulation results indicate that increasing flue gas recirculation increases the energy consumed by the recirculation compressor and the energy produced by the gas turbine. On the other hand, it decreases the production of energy of the steam turbine and the energy consumed by the pump of the steam cycle. The overall energy efficiency of the SNGCC power plant is highest (41.09%) at a value of 0.20 of the flue gas recirculation. However, the flue gas composition with a FGR ratio of 0.37 is more suitable for effective absorption of carbon dioxide by amine solutions. Based on the low heating value (LHV) of hydrogen, the corresponding overall efficiency of the power plant is 39.18% and the net power output of the plant is 1273 kW for consumption of 97.5 kg/hr. of hydrogen.
文摘A numerical calculation of a 3000MWt MHD steam combined cycle system with tail gasification is described . The research scheme has been set up and the parameters of this system have been designed. Then the efficiency of the combined cycle system has been calculated which is up to 53.9%.
基金financial support from the Fundamental Research Project in the Chinese National Sciences and Technology Major Project (Grant No.2017-1-0002-0002)。
文摘Exhaust gas recirculation control(EGRC),an inlet air heating technology,can be utilized in combination with inlet/variable guide vane control(IGV/VGVC) and fuel flow control(FFC) to regulate the load,thereby effectively improving the part-load(i.e.,off-design) performance of the gas turbine combined cycle(GTCC).In this study,the E-,F-,and H-Class EGR-GTCC design and off-design system models were established and validated to perform a comparative analysis of the part-load performance under the EGR-IGV-FFC and conventional IGV-FFC strategies in the E/F/H-Class GTCC.Results show that EGR-IGV-FFC has considerable potential for the part-load performance enhancement and can show a higher combined cycle efficiency than IGV-FFC in the E-,F-,and H-Class GTCCs.However,the part-load performance improvement in the corresponding GTCC was weakened for the higher class of the gas turbine because of the narrower load range of EGR action and the deterioration of the gas turbine performance.Furthermore,EGR-IGV-FFC was inferior to IGV-FFC in improving the performance at loads below 50% for the H-Class GTCC.The results obtained in this paper could help guide the application of EGR-IGV-FFC to enhance the part-load performance of various classes of GTCC systems.
基金Sponsored by the Liaoning Provincial Science and Technology Program Project(Grant No.2012219024)
文摘In order to improve efficiency of a combined power system in which waste heat from exhaust gas could be efficiently recovered and cold energ^^ of liquefied natural gas （LNG） could be fully utilized as well. A system simulation and ther^nodynamic analysis were carried out, the Kalina cycle was reorganized by changing the concentration of “basic composition”, so that a better thermal matching in the heat exchanger could be obtained and the irreversibility of the system was decreased. It was found that the Kalina cycle generally used in the bottom of combined power cycle could also be used to recover the cold energy of LNG. The results show that the exergy efficiency of 42.97% is obtained. Compared with the previous system attained the exergy efficiency of 39.76%, the improved system has a better performance.
文摘Forecasts of the various types of gas turbines economics and performance of gas turbine combined cycle （GTCC） with will help power plant designers to select the best type of gas turbine for future Chinese powerplants. The cost and performance of various designs were estimated using the commercial software GT PRO. Improved GTCC output will increase the system efficiency which may induce total investment and will certainly increase the cumulative cash which then will induce the cost and the payback period. The relative annual fuel output increases almost in proportion to the relative GTCC output. China should select the gas turbine that provides the most economical output according to its specific conditions. The analysis shows that a GTCC power plant with a medium-sized 100 to 200 MW output gas turbine is the most suitable for Chinese investors.
基金supported by the China Postdoctoral Science Foundation(Grant number:370140).
文摘After long-term operation,the performance of components in the GTCC system deteriorates and requires timely maintenance.Due to the inability to directly measure the degree of component malfunction,it is necessary to use advanced exergy analysis diagnosis methods to characterize the components’health condition(degree of malfunction)through operation data of the GTCC system.The dissipative temperature is used to describe the degree of malfunction of different components in the GTCC system,and an advanced exergy analysis diagnostic method is used to establish a database of overall operating condition component malfunctions in theGTCC system.Ebsilon software is used to simulate the critical parameters of the malfunctions of the GTCC system components and to obtain the changes in the dissipative temperature of different components.Meanwhile,the fuel consumption and economic changes of the GTCC system on a characteristic power supply day under health and malfunction conditions are analyzed.Finally,the effects of maintenance costs,electricity,and gas prices on maintenance expenses and profits are analyzed.The results show that the GTCC system maintenance profit is 6.07$/MWh,while the GTCC system maintenance expense is 5.83$/MWh.Compared with the planned maintenancemode,the malfunction maintenance mode saves 0.24$/MWh.Simultaneously,the maintenance coefficient of GTCC should be adjusted under different malfunctions to obtain a more accurate maintenance period.
文摘Maintenance scheduling and asset management practices play an important role in power systems,specifically in power generating plants.This paper presents a novel riskbased framework for a criticality assessment of plant components as a means to conduct more focused maintenance activities.Critical components in power plants that influence overall system performance are identified by quantifying their failure impact on system reliability,electric safety,cost,and the environment.Prioritization of plant components according to the proposed risk-based method ensures that the most effective and techno-economic investment decisions are implemented.This,in turn,helps to initiate modern maintenance approaches,such as reliability-centered maintenance(RCM).The proposed method is applied to a real combined cycle power plant(CCPP)in Iran,composed of two gas turbine power plants(GTPP)and one steam turbine power plant(STPP).The results demonstrate the practicality and applicability of the presented approach in real world practices.
基金supported by the National Key Fundamental Research Project of Science and Technology (973,No.G1999022104-1)NSFC (No.29976029)the National 95 plane (No.97-A26-03-02-02)
文摘The most difficult problem in hot gas desulfurization in Integrated Coal Gasification Combined Cycle （IGCC） is the pulverization of sulfur removal sorbents.Appropriate binders for hot gas sulfur removal sorbents can solve the pulverization problem.In this paper,six sorbents with binders of different argillaceous minerals were prepared by mechanical mixing method.Desulfurization behavior for hot gas desulfurization sorbents was investigated in a fixed-bed reactor.Result showed that sorbent NTKW2 with binder of clay had a better sulfidation performance.NTKW2 had a more stable performance than other sorbents in the continuous sulfidation-regeneration cycles.Sulfur capacity of sorbent remained the same in each cycle.The desulfurization efficiency and mechanical strength of NTKW2 were the best among the tested sorbents.The behavior of NTKW2 at different temperatures showed different performances,and the best reaction temperature was 550 ℃.Higher heat stability,sulfur capacity and desulfurization efficiency were found on NTKW2 in six continuous sulfidation-regeneration cycles.
基金Supported by China National "95" Project (96-A26-03-02-01) China National "863" Project (2002AA529080) and China-UK, BRICC, CCRI
文摘Two Zn-based sorbents, L-991 and L-992 used for hot gas desulfurization (HGD) were introduced. Zn/Ti ratio of the two sorbent was 1:1 and 2:3 resptively and a certain proportion of Cu and Mn metal oxide were added into L-992, which provided better performance than L-991 in aspects of suitable work temperature, sulfur capacity and agglomeration on the surface of sorbent particles. The evaluation tests were done on both sorbents include multi cycles tests. ARD and SEM analysis were done on fresh and post tests sorbent. During continuous sulfidation/regeneration, the H2S concentra- tion can be reduced from about 10 g/m3 to less than 20 mg/m3, the H2S removal effi- ciency >99 %.
文摘Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit with coal water slurry gasifier was simulated and calculated using THERMOFLEX software, and the relations of oxygen coal ratio (Roc), water coal ratio (Rsc), gasification pressure, gasification temperature and cold gas efficiency were mostly researched. The results show that Roc and Rsc have effect of mutual restriction on gasification temperature, cold gas efficiency and syngas composition. Gasification pressure mainly determines the capacity of the gasifier, little effects on syngas composition.
文摘Carbon capture and storage （CCS） technology will play a critical role in reducing anthropogenic carbondioxide （CO2） emission from fossil-fired power plants and other energy-intensive processes. However, theincrement of energy cost caused by equipping a carbon capture process is the main barrier to its commer-cial deployment. To reduce the capital and operating costs of carbon capture, great efforts have been madeto achieve optimal design and operation through process modeling, simulation, and optimization. Accuratemodels form an essential foundation for this purpose. This paper presents a study on developing a moreaccurate rate-based model in Aspen Plus for the monoethanolamine （MEA）-based carbon capture processby multistage model validations. The modeling framework for this process was established first. The steady-state process model was then developed and validated at three stages, which included a thermodynamicmodel, physical properties calculations, and a process model at the pilot plant scale, covering a wide rangeof pressures, temperatures, and CO2 loadings. The calculation correlations of liquid density and interfacialarea were updated by coding Fortran subroutines in Aspen Plus. The validation results show that the cor-relation combination for the thermodynamic model used in this study has higher accuracy than those ofthree other key publications and the model prediction of the process model has a good agreement with thepilot plant experimental data. A case study was carried out for carbon capture from a 250 MWe combinedcycle gas turbine （CCGT） power plant. Shorter packing height and lower specific duty were achieved usingthis accurate model.
文摘The objective of the first part of the investigation was to use Aspen Plus software and the Redlich-Kwong-Soave equation of state in order to simulate an adiabatic methanation reactor for the production of synthetic natural methane (SNG) using 1 kg/hr<span><span><span style="font-family:;" "=""> </span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">of carbon dioxide. In this paper, we define the Synthetic Natural Gas Combined Cycle (SNGCC) as a combined cycle power plant where the fuel is synthetic natural gas (SNG) produced by a methanation reactor. The feed of the methanation reactor is the recycled stream of carbon dioxide of a CO<sub>2</sub> capture unit treating the flue gas of the SNGCC power plant. The objective of the second part of the investigation is the utilization of Aspen plus software with SRK equation of state for the simulation of the SNGCC power plant. The metallurgical limitation of the gas turbine was fixed at 1300<sup><span style="font-family:Verdana, Helvetica, Arial;white-space:normal;background-color:#FFFFFF;">°<span style="font-family:Verdana;white-space:normal;"></span></span></sup></span></span>C in this investigation. For effective absorption by amine solutions, the molar percentage of CO<sub>2</sub> in the flue gas should be higher than 10%. Moreover, in order to reduce technical problems linked to oxidative degradation of amine in the CO<sub>2</sub> capture plant, the percentage of O<sub>2</sub> in the flue gas should also be lower than 5%. To reach this goal, the primary air for combustion has 10% excess air (compared to stoichiometric air) and 37% of the flue </span><span style="font-family:Verdana;">gas leaving the SNGCC is recirculated as the secondary air for cooling the</span><span style="font-family:Verdana;"> turbine</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">.</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> As a result, the concentration of CO<sub>2</sub> and O<sub>2</sub></span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of the flue gas entering the CO<sub>2</sub> capture unit were respectively equal to 10.2% and 2.01%. The simulation results of the SNGCC power plant indicate that 6.6 MJ of electricity are produced for each kg of carbon dioxide recycled from the CO<sub>2</sub> capture unit of the power plant. In other terms, the production of the 24.88 kg/hr</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of synthetic natural gas (SNG) consumes 62.36 kg/hr</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of recycled carbon dioxide and 16.4 kg/hr</span></span></span><span><span><span style="font-family:;" "=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">of hydrogen. The SNG produced by the methanation reactor of the power plant generates 114 kW of electricity. It is assumed in this paper that the hydrogen needed for the methanation of carbon dioxide is a product of a catalytic reforming plant that produces gasoline from heavy naphta fraction of an atmospheric distillation unit of crude oil.</span></span></span>
文摘There is a false notion of existing available, abundant, and long lasting fuel energy in the Gulf Cooperation Council (GCC) Countries;with continual income return from its exports. This is not true as the sustainability of this income is questionable. Energy problems started to appear, and can be intensified in coming years due to continuous growth of energy demands and consumptions. The demands already consume all produced Natural Gas (NG) in all GCC, except Qatar;and the NG is the needed fuel for Electric Power (EP) production. These countries have to import NG to run their EP plants. Fuel oil production can be locally consumed within two to three decades if the current rate of consumed energy prevails. The returns from selling the oil and natural gas are the main income to most of the GCC. While NG and oil can be used in EP plants, NG is cheaper, cleaner, and has less negative effects on the environment than fuel oil. Moreover, oil has much better usage than being burned in steam generators of steam power plants or combustion chambers of gas turbines. Introducing renewable energy or nuclear energy may be a necessity for the GCC to keep the flow of their main income from exporting oil. This paper reviews the GCC productions and consumptions of the prime energy (fuel oil and NG) and their role in electric power production. The paper shows that, NG should be the only fossil fuel used to run the power plants in the GCC. It also shows that the all GCC except Qatar, have to import NG. They should diversify the prime energy used in power plants;and consider alternative energy such as nuclear and renewable energy, (solar and wind) energy.
文摘Qatar energy consumptions are among the highest in the world, and can easily serve double the present population. Energy conservation is a must, as the energy resources are finite, and their consumptions are increasing at alarming rates. The country depends on desalted seawater, which consumes extensive amounts of energy, and is produced by using the least energy efficient desalting system. The desalination process is vulnerable to many factors, and strategic water storage needs to be built. The high energy consumptions are ruining the air and marine environments. Several suggestions are introduced to conserve energy in the Cogeneration Power Desalting Plants (CPDP), by moving to replace the Multi Stage Flash (MSF) desalting system by the energy efficient Seawater Reverse Osmosis System (SWRO);fully utilizing the installed power capacity to desalt water in winter, when electric power load is low, and during summer non-peak hours for strategic water storage;and modifying the simple Gas Turbines (GT) Power cycle plants to GT combined cycle to raise the Electric Power (EP) generation efficiency (to about 50%).
基金This research work is supported by the National Science and Technology Major Project(2017-V-0004-0054)the National Natural Science Foundation of China(Grant No.52125603)+1 种基金the National Natural Science Foundation of China(Grant No.11972139)the Fundamental Research Funds for the Central Universities(HIT.BRET.2021006 and FRFCU5710094620).
文摘Airbreathing aero-engines are regarded as excellent propulsion devices from ground takeoff to hypersonic flight,and require control systems to ensure their efficient and safe operation.Therefore,the present paper aims to provide a summary report of recent research progress on airbreathing aero-engine control to help researchers working on this topic.First,five control problems of airbreathing aero-engines are classified:uncertainty problem,multiobjective and multivariable control,fault-tolerant control,distributed control system,and airframe/propulsion integrated control system.Subsequently,the research progress of aircraft gas turbine engine modelling,linear control,nonlinear control,and intelligent control is reviewed,and the advantages and disadvantages of various advanced control algorithms in aircraft gas turbine engines is discussed.Third,several typical hypersonic flight tests are investigated,and the modelling and control issues of dual-mode scramjet are examined.Fourth,modelling,mode transition control and thrust pinch control for turbine-based combined cycle engines are introduced.Followed,significant hypersonic airframe/propulsion integrated system control is analysed.Finally,the study provides specific control research topics that require attention on airbreathing aero-engines.
