Simulation of Optimizing the Partial Load Performance of a Gas Turbine Combined Cycle Using Exhaust Heat Recuperation and Inlet Bleed Heating

2021 ◽  
Author(s):  
Tong Seop Kim ◽  
Seongwon Moon
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Partial Load ◽  
Exhaust Heat ◽  
Heat Recuperation

Simulation of Optimizing the Partial Load Performance of a Gas Turbine Combined Cycle Using Exhaust Heat Recuperation and Inlet Bleed Heating

2020 ◽  
Author(s):  
Seong Won Moon ◽  
Tong Seop Kim
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Operating Range ◽  
Cycle Simulation ◽  
Partial Load ◽  
Exhaust Heat ◽  
Load Regime ◽  
Heat Recuperation

Abstract This paper proposes a novel method to extend the operating range and improve the partial load efficiency of the gas turbine combined cycle (GTCC). The combination of exhaust heat recuperation and inlet bleed heating (IBH) was evaluated through a cycle simulation. The degree of heat recuperation was modulated during partial load operation to enhance the cycle efficiency. The recuperation ratio was modulated before control of the variable inlet guide vane (VIGV) began. This means that the recuperation control covers the high partial load regime. The gas turbine power remained almost constant in this regime because the inlet flow rate and turbine inlet temperature were kept constant. In contrast, the power of the bottoming cycle decreased with increasing recuperation ratio due to the decrease in exhaust gas energy. After the recuperation ratio reached a limit, the load control was the same, as in conventional plants: VIGV control followed by fuel only control. The purpose of using IBH was to reduce CO emissions in the low load regime. Some of the compressor discharge air was recirculated to the compressor inlet, and the combustion temperature was maintained at a high level. Both IBH and recuperation were effective in extending the operating range. The turndown ratio was predicted to decrease by approximately 10%p. The efficiency remained higher than the full load efficiency over a wide partial load range. The efficiency of the recuperated GTCC was 4.1%p higher at 50% power than that of the conventional GTCC.

Simulation of Optimizing the Partial Load Performance of a Gas Turbine Combined Cycle Using Exhaust Heat Recuperation and Inlet Bleed Heating

2020 ◽  
Author(s):  
Seong Won Moon ◽  
Tong Seop Kim
Keyword(s):  
Gas Turbine ◽  
Combined Cycle ◽  
Inlet Guide Vane ◽  
Inlet Temperature ◽  
Operating Range ◽  
Cycle Simulation ◽  
Partial Load ◽  
Exhaust Heat ◽  
Load Regime ◽  
Heat Recuperation

Abstract Extending the operating range and improving the partial load efficiency of the gas turbine combined cycle (GTCC) is becoming increasingly important. This paper proposes a novel method to achieve the two goals simultaneously. To fulfill the research objective, the combination of exhaust heat recuperation and inlet bleed heating (IBH) was adopted and evaluated. A cycle simulation was conducted to confirm whether the research goal could be achieved. A recuperator was installed between the compressor and combustor of the gas turbine, and the degree of heat recuperation was modulated during partial load operation to enhance the cycle efficiency compared to the conventional GTCC plant. In contrast to the conventional GTCC plant, the recuperation ratio was modulated before control of the variable inlet guide vane (VIGV) began. This means that the recuperation control covers the high partial load regime. The gas turbine power remained almost constant in this regime because the inlet flow rate and turbine inlet temperature were kept constant. In contrast, the power of the bottoming cycle decreased with increasing recuperation ratio due to the decrease in exhaust gas energy. After the recuperation ratio reached a limit, the load control was the same, as in conventional plants: VIGV control followed by fuel only control. The purpose of using IBH was to reduce CO emissions in the low load regime. Some of the compressor discharge air was recirculated to the compressor inlet, and the combustion temperature was maintained at a high level. The simulation showed that both IBH and recuperation are effective in extending the operating range. The predicted reduction in the turndown ratio was approximately 10%p. The partial load efficiency improvement by the recuperation was sensible. The efficiency remained higher than the full load efficiency over a wide partial load range. The efficiency of the recuperated GTCC was 4.1%p higher at 50% power than that of the conventional GTCC.

Effect of Coolant Injection Angle on Nozzle Endwall Film Cooling: Experimental and Numerical Analysis in Linear Cascade

2018 ◽  
Author(s):  
Lamyaa El-Gabry ◽  
Hongzhou Xu ◽  
Kevin Liu ◽  
James Chang ◽  
Michael Fox
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Surface Film ◽  
Combined Cycle ◽  
Gas Temperature ◽  
Injection Angle ◽  
Linear Cascade ◽  
Cfd Models ◽  
Coolant Injection ◽  
Exhaust Heat

Gas turbine components can withstand gas temperatures exceeding the melting point of the alloys they’re made of due to increasingly effective cooling methods. Increasing the operating temperature of a gas turbine is key to improving its power density and exhaust heat for steam or combined-cycle efficiency. In the turbine, the component that experiences the highest gas temperature is the vane directly downstream of the combustor; the most complex flow field in a vane occurs near the endwall. In this study, an experimental investigation is carried out to determine the effect of coolant injection angle and mass flow ratio on film effectiveness on the endwall using the pressure sensitive paint technique for various configurations of jump cooling hole configurations. Two rows of angled holes are upstream of an uncooled vane in a three-vane linear cascade. Injection angle including compound angle is varied from 20 to 60 and coolant to mainstream massflux ratio is varied from 0.5% to 3%. Contours of endwall surface film effectiveness are presented along with span-averaged film effectiveness. CFD models of the cascade are developed using a commercial solver to predict film effectiveness for some of the test conditions and comparisons are made between the experimental and numerical results. The CFD models provide further insight into the flow field and explain trends observed in the experiment by understanding the interaction of jump coolant flow with the 3D endwall mainstream flows.

Combined Heat and Power: Gas Turbine Operational Flexibility

2013 ◽  
Author(s):  
James DiCampli
Keyword(s):  
Gas Turbine ◽  
Urban Areas ◽  
Gas Turbines ◽  
Heat Recovery ◽  
National Fire Protection Association ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Electricity Production ◽  
Exhaust Heat ◽  
Gas Fuel

Combined heat and power (CHP) is an application that utilizes the exhaust heat generated from a gas turbine and converts it into a useful energy source for heating & cooling, or additional electric generation in combined cycle configurations. Compared to simple-cycle plants with no heat recovery, CHP plants emit fewer greenhouse gasses and other emissions, while generating significantly more useful energy per unit of fuel consumed. Clean plants are easier to permit, build and operate. Because of these advantages, projections show CHP capacity is expected to double and account for 24% of global electricity production by 2030. An aeroderivative power plant has distinct advantages to meet CHP needs. These include high thermal efficiency, low cost, easy installation, proven reliability, compact design for urban areas, simple operation and maintenance, fuel flexibility, and full power generation in a very short time period. There has been extensive discussion and analyses on modifying purge requirements on cycling units for faster dispatch. The National Fire Protection Association (NFPA) has required an air purge of downstream systems prior to startup to preclude potentially flammable or explosive conditions. The auto ignition temperature of natural gas fuel is around 800°F. Experience has shown that if the exhaust duct contains sufficient concentrations of captured gas fuel, and is not purged, it can ignite immediately during light off causing extensive damage to downstream equipment. The NFPA Boiler and Combustion Systems Hazards Code Committee have developed new procedures to safely provide for a fast-start capability. The change in the code was issued in the 2011 Edition of NFPA 85 and titled the Combustion Turbine Purge Credit. For a cycling plant and hot start conditions, implementation of purge credit can reduce normal start-to-load by 15–30 minutes. Part of the time saving is the reduction of the purge time itself, and the rest is faster ramp rates due to a higher initial temperature and pressure in the heat recovery steam generator (HRSG). This paper details the technical analysis and implementation of the NFPA purge credit recommendations on GE Power and Water aeroderivative gas turbines. This includes the hardware changes, triple block and double vent valve system (or drain for liquid fuels), and software changes that include monitoring and alarms managed by the control system.

Theoretical Study of the Operation Performance of a Natural Gas CCHP System under Variable Loads

2011 ◽  
Vol 71-78 ◽  
pp. 1765-1768
Author(s):  
Hong Mei Zhu ◽  
Heng Sun ◽  
Tian Quan Pan
Keyword(s):  
Natural Gas ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Theoretical Study ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Operation Performance ◽  
Exhaust Heat ◽  
Calculation Results ◽  
Cooling Loads

A theoretical study of the performance of a CCHP system using natural gas as fuel which consists of gas turbine-steam turbine combined cycle, absorption refrigeration unit and exhaust heat boiler under variable loads was carried out. Two methods to adjust the electric and cooling loads are employed here. One method is to increase the outlet pressure of the steam turbine in the Rankine cycle. Another way is to change the air coefficient of the gas turbine. The calculation results show that the first method can obtain higher energy efficient and is the preferred method. The second way can be employed in case that further more cooling is required.

Aeroderivative Combined Heat and Power Fundementals and Applications

2012 ◽  
Author(s):  
James DiCampli
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Energy System ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Draft Guidance ◽  
Distributed Energy ◽  
Improve Energy Efficiency ◽  
Exhaust Heat

Combined heat and power (CHP), is an application that utilizes the exhaust heat generated from a gas turbine and converts it into a useful energy source for heating & cooling, or additional electric generation in combined cycle configurations. Compared to simple-cycle plants with no heat recovery, CHP plants emit fewer greenhouse gasses and other emissions, while generating significantly more useful energy per unit of fuel consumed. Clean plants are easier to permit, build and operate. Because of these advantages, Aeroderivative gas turbines will be a major part of global CHP growth, particularly in China. In order to improve energy efficiency and reduce CO2 emissions, China is working to build ∼1000 new plants of Natural Gas Distributed Energy System (NG-DES) in the next five years. These plants will replace conventional coal-fired plants with combined cooling, heating and power (CCHP) systems. China power segments require an extensive steam supply for cooling, heating and industrial process steam demands, as well as higher peak loads due to high population densities and manufacturing growth rates. GE Energy Aero recently entered the CCHP segment in China, and supported the promotion of codes and standards for NG-DES policy, and is developing optimized CCHP gas turbine packages to meet requirements. This paper reviews those policies and requirements, and presents technical case studies on CCHP applications. Appendix B highlights China’s draft “Guidance Opinions on Developing Natural-Gas Distributed Energy.”

Technical Evaluation and Applications of Heat Recovery From Simple Cycle Gas Turbine Exhaust Systems

2020 ◽  
Author(s):  
Bouria Faqihi ◽  
Fadi A. Ghaith
Keyword(s):  
Pressure Drop ◽  
Gas Turbine ◽  
Heat Recovery ◽  
Power Plants ◽  
Thermal Power ◽  
Combined Cycle ◽  
Heat Extraction ◽  
Simple Cycle ◽  
System Pressure ◽  
Exhaust Heat

Abstract In the Gulf Cooperation Council region, approximately 70% of the thermal power plants are in a simple cycle configuration while only 30% are in combined cycle. This high simple to combined cycle ratio makes it of a particular interest for original equipment manufacturers to offer exhaust heat recovery upgrades to enhance the thermal efficiency of simple cycle power plants. This paper aims to evaluate the potential of incorporating costly-effective new developed heat recovery methods, rather than the complex products which are commonly available in the market, with relevant high cost such as heat recovery steam generators. In this work, the utilization of extracted heat was categorized into three implementation zones: use within the gas turbine flange-to-flange section, auxiliary systems and outside the gas turbine system in the power plant. A new methodology was established to enable qualitative and comparative analyses of the system performance of two heat extraction inventions according to the criteria of effectiveness, safety and risk and the pressure drop in the exhaust. Based on the conducted analyses, an integrated heat recovery system was proposed. The new system incorporates a circular duct heat exchanger to extract the heat from the exhaust stack and deliver the intermediary heat transfer fluid to a separate fuel gas exchanger. This system showed superiority in improving the thermodynamic cycle efficiency, while mitigating safety risks and avoiding undesired exhaust system pressure drop.

scholarly journals Effect of Inlet Air Heating on Gas Turbine Efficiency under Partial Load

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3327 ◽  
Author(s):  
ZhiTan Liu ◽  
XiaoDong Ren ◽  
ZhiYuan Yan ◽  
HongFei Zhu ◽  
Tao Zhang ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Waste Heat ◽  
Heating Temperature ◽  
Calculation Model ◽  
Combined Cycle ◽  
Characteristic Curves ◽  
Turbine Efficiency ◽  
Air Heating ◽  
Partial Load ◽  
Heating Technology

A novel heating technology is presented to analyze the influence of inlet air heating on gas turbine efficiency under partial load. This technology uses the waste heat of a low-temperature heat sources, which includes but is not limited to the exhaust gas of a combined-cycle heat-recovery steam generator or a single-cycle gas turbine. A calculation model of the equilibrium running point is used for the given load and the characteristic curves of the compressor and the turbine to study the mechanism of the inlet air heating technology. Then, the equilibrium running line is calculated and drawn in the characteristic curves of the compressor and the turbine. The factors for gas turbine efficiency are discussed through the calculated equilibrium running line. The results show that an increase in inlet air temperature has considerable potential for improving gas turbine efficiency due to the increase in compressor and turbine efficiency. This finding is different from traditional viewpoints. Meanwhile, each partial load has an optimum heating temperature which becomes higher when the load is lower.

Conceptual Recovery of Exhaust Heat From a Conventional Gas Turbine by an Inter-Cooled Inverted Brayton Cycle

1999 ◽  
Author(s):  
Y. Tsujikawa ◽  
K. Ohtani ◽  
K. Kaneko ◽  
T. Watanabe ◽  
S. Fujii
Keyword(s):  
Gas Turbine ◽  
Heat Recovery ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Brayton Cycle ◽  
Turbine Performance ◽  
Exhaust Heat ◽  
Manufacturing Techniques ◽  
Industrial Gas Turbine ◽  
Made In

Improvements in industrial gas turbine performance have been made in last decade. Advances in the gas turbine technologies such as higher turbine inlet temperature, materials, and manufacturing techniques justify the development of new combined or cogeneration cycle schemes, with more advance heat recovery capabilities. This paper describes the performance analysis of an Inverted Brayton Heat Recovery (IBHR) cycle, which is combined with conventional gas turbine and worked as a bottoming cycle. The optimum characteristics have been calculated and it is shown that this cycle is superior to the conventional combined cycle and cogeneration systems in terms of thermal efficiency and specific output. The main feature of this new concept is that the inverted Brayton cycle with inter-cooling is introduced. Further, a new estimating function, “the emission coefficient of carbon-dioxide” has been successfully introduced to assess the environmental compatibility.

scholarly journals Modeling an effective method to utilize secondary energy resources of a combined cycle gas turbine based on the CCGT-420T

2020 ◽  
Vol 21 (1) ◽  
pp. 27-35
Author(s):  
Yuri A. Antipov ◽  
Ivan K. Shatalov ◽  
Kirill V. Shkarin ◽  
Anna S. Barybina ◽  
Yana A. Ogneva ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Power Plants ◽  
Economic Benefits ◽  
Combined Cycle ◽  
Energy Resources ◽  
Coefficient Of Performance ◽  
Secondary Energy ◽  
Exhaust Heat ◽  
Heat Pump Unit ◽  
Secondary Energy Resources

Nowadays, improving the efficiency of power plants by utilizing secondary energy resources is gaining more attention in the energy sector. In this paper, the combined cycle gas turbine (CCGT-420T) was considered, where exhaust heat from the main and auxiliary equipment is utilized, and sent to a water supply system through a closed-circuit heat exchanger, as a result, the heat transferred ( Q 6.4 MW) is rejected into the environment through a cooling tower. Moreover, an effective modelling method for utilizing heat in a closed cycle, using a steam compressing heat pump unit (HPU) is proposed. In addition, a calculation of the effectiveness of utilizing secondary energy resources depending on the number of HPU stages. In addition, the calculation of the effectiveness of the use of secondary energy resources depending on the number of stages of HPU was carried out. Several options of the model were discussed in this work, such as, two-, three-, and four-stage HPU and the coefficient of performance was calculated. Moreover, the work of these compressors for each option of the model was discussed in this work. Finally, the economic benefits of using of a multi-stage HPU instead of a traditional one-stage HPU during the annual operation of the CCGT-420T was discussed.

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