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.

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.”

Techno-Economic Optimization of Electricity and Heat Production in a Gas-Fired Combined Heat and Power Plant With a Heat Accumulator

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Piotr Żymełka ◽  
Marcin Szega ◽  
Paweł Madejski
Keyword(s):  
Gas Turbine ◽  
Heat Production ◽  
Optimization Algorithm ◽  
Gas Turbines ◽  
Heat Recovery ◽  
High Reliability ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Time Step ◽  
Heat Accumulator

Abstract At present, power systems based on gas turbines are mainly used for electricity and heat generation. Gas turbines are used in industrial and institutional applications due to high-temperature exhaust, which can be used for heating, drying, or process steam production. The combined cycle gas turbine plants are a mature technology with high reliability and offering rapid response to changing demand for electricity and heat. The combination of a gas turbine with a heat recovery system and a heat accumulator makes the combined heat and power (CHP) plant a flexible unit. The paper presents the optimization tool for the planning process of electricity and heat production in the gas-fired CHP plant with a heat accumulator. The detailed mathematical model of the analyzed cogeneration plant was developed with the EBSILON®Professional and verified based on the results from on-site tests and warranty measurements. The implemented optimization algorithm is used to maximize the profits of the CHP plant operation. The presented solution is based on an evolutionary algorithm. The optimization algorithm is applied to the production determination for the day-ahead planning horizon, with 1-h time step. The obtained results show that the developed optimization model is a reliable and efficient tool for production planning in a CHP plant with gas turbines. The comparative exergy analysis for different technologies of heat recovery from gas turbine exhaust gases was performed to evaluate the quality of the energy conversion process in the CHP plant.

HRSG Duct Firing Revisited

2018 ◽  
Author(s):  
S. Can Gülen
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Fossil Fuel ◽  
Heat Rate ◽  
Combined Cycle ◽  
Efficiency Improvement ◽  
Combined Cycle Power Plant

Duct firing in the heat recovery steam generator (HRSG) of a gas turbine combined cycle power plant is a commonly used method to increase output on hot summer days when gas turbine airflow and power output lapse significantly. The aim is to generate maximum possible power output when it is most needed (and, thus, more profitable) at the expense of power plant heat rate. In this paper, using fundamental thermodynamic arguments and detailed heat and mass balance simulations, it will be shown that, under certain boundary conditions, duct firing in the HRSG can be a facilitator of efficiency improvement as well. When combined with highly-efficient aeroderivative gas turbines with high cycle pressure ratios and concomitantly low exhaust temperatures, duct firing can be utilized for small but efficient combined cycle power plant designs as well as more efficient hot-day power augmentation. This opens the door to efficient and agile fossil fuel-fired power generation opportunities to support variable renewable generation.

scholarly journals Repowering of a Small Utility: A Unique Solution to a Unique Problem

1979 ◽  
Author(s):  
L. F. Fougere ◽  
H. G. Stewart ◽  
J. Bell
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Steam Generator ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Electric Utility ◽  
Combined Cycle ◽  
Steam Boiler ◽  
Heat Recovery Steam Generator ◽  
Turbine Generator

Citizens Utilities Company’s Kauai Electric Division is the electric utility on the Island of Kauai, fourth largest and westernmost as well as northernmost of the Hawaiian Islands. As a result of growing load requirements, additional generating capacity was required that would afford a high level of reliability and operating flexibility and good fuel economy at reasonable capital investment. To meet these requirements, a combined cycle arrangement was completed in 1978 utilizing one existing gas turbine-generator and one new gas turbine-generator, both exhausting to a new heat recovery steam generator which supplies steam to an existing steam turbine-generator. Damper controlled ducting directs exhaust gas from either gas turbine, one at a time, through the heat recovery steam generator. The existing oil-fired steam boiler remains available to power the steam turbine-generator independently or in parallel with the heat recovery steam generator. The gas turbines can operate either in simple cycle as peaking units or in combined cycle, one at a time, as base load units. This arrangement provides excellent operating reliability and flexibility, and the most favorable economics of all generating arrangements for the service required.

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.

Evaluation for Scalability of a Combined Cycle Using Gas and Bottoming SCO2 Turbines

2015 ◽  
Author(s):  
Leonid Moroz ◽  
Petr Pagur ◽  
Oleksii Rudenko ◽  
Maksym Burlaka ◽  
Clement Joly
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Supercritical Co2 ◽  
Power Plants ◽  
Combined Cycle ◽  
Electricity Production ◽  
Working Fluid ◽  
Gas Temperature ◽  
Cycle System ◽  
Gas Turbine Exhaust

Bottoming cycles are drawing a real interest in a world where resources are becoming scarcer and the environmental footprint of power plants is becoming more controlled. Reduction of flue gas temperature, power generation boost without burning more fuel and even production of heat for cogeneration applications are very attractive and it becomes necessary to quantify how much can really be extracted from a simple cycle to be converted to a combined configuration. As supercritical CO2 is becoming an emerging working fluid [2, 3, 5, 7 and 8] due not only to the fact that turbomachines are being designed significantly more compact, but also because of the fluid’s high thermal efficiency in cycles, it raises an increased interest in its various applications. Evaluating the option of combined gas and supercritical CO2 cycles for different gas turbine sizes, gas turbine exhaust gas temperatures and configurations of bottoming cycle type becomes an essential step toward creating guidelines for the question, “how much more can I get with what I have?”. Using conceptual design tools for the cycle system generates fast and reliable results to draw this type of conclusion. This paper presents both the qualitative and quantitative advantages of combined cycles for scalability using machines ranging from small to several hundred MW gas turbines to determine which configurations of S-CO2 bottoming cycles are best for pure electricity production.

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 100 MW Combined Cycle Achieves 7000 BTU/KWH Heat Rate at JFK International Airport

1992 ◽  
Author(s):  
Donald A. Kolp ◽  
Richard Roberts ◽  
Soo Young Kim
Keyword(s):  
Gas Turbine ◽  
Heat Recovery ◽  
Waste Heat ◽  
Water Injection ◽  
Heat Rate ◽  
Combined Cycle ◽  
Dual Function ◽  
Electric Generator ◽  
International Airport ◽  
Gas Fuel

In early 1994 a 100 MW LM6000 combined cycle cogeneration plant will begin operation at New York City’s John F. Kennedy International Airport. Thanks to the extremely high simple cycle efficiency of the LM6000 gas turbine (8200 BTU/KWH, 8650 kJ/KWH-LHV dry) and a sophisticated three-pressure steam generating system, a heat rate below 7000 BTU/KWH-LHV (7380 kJ/KWH-LHV) is expected when operating in combined cycle mode. The dual-spool LM6000 achieves its efficiency by means of a 30:1 compression ratio. 2100 F. (1149 C.) firing temperatures and the direct coupling of the low compressor/turbine rotor to the electric generator. The efficiency of the heat recovery steam generator results from the use of three economizers, three evaporators and two superheaters combined with a patented feedwater heating system which yields a 245 F. (118 C.) exhaust stack temperature. Operating flexibility is essential in this application. While the dual-fueled plant is designed for pure combined cycle operation, most of the time it will operate in a cogeneration mode — producing up to 250 × 106 BTU/HR (264 × 106 kJ/HR) of steam for heating in the winter and 7000 (24,618 KW) tons of chilling for air conditioning airport terminals in the summer. The waste heat boilers are designed to be supplementary fired on gas fuel when the airport requires the 110 MW maximum capacity of the plant simultaneously with the maximum thermal load of 250 × 106 BTU/HR (264 × 106 kJ/HR). NOx emissions are controlled with a combination of water injection in the turbine combustors and a dual-function catalyst SCR/CO converter. CO is controlled by means of the converter. Combined gas turbine and duct burner NOx is maintained below 9.0 PPMV dry (@ 15% O2) and CO below 1.5 PPH (0.68 KG/HR) dry (@ 15% O2) when operating on gas fuel. Cycle details, equipment selection and operation as well as the plant economics provide a useful insight into the benefits of these recent developments in gas turbine and heat recovery combined cycle cogeneration technology.

scholarly journals User-Oriented Gas Turbine Research at KEMA

1996 ◽  
Author(s):  
R. A. Rooth
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
High Efficiency ◽  
Turbine Rotor ◽  
Combined Cycle ◽  
Rotor Blades ◽  
Electricity Production ◽  
Combustion Chambers ◽  
Power Stations

In the 80’s and early 90’s, in the Netherlands 11 combi blocks with prefitted gas turbines have been built. This repowering programme increased the efficiency of the units involved by several percentage points. Additionally, the commissioning of the five 335 MWe units at the Eems power station is in progress and plans exist for a farther seven 250 MW heat and power stations. This means that by 2002 the generating industry will be operating seventy-five gas turbines with a total gas turbine power of 5700 MWe. These data serve to illustrate mat gas turbines will be the workhorse of the Dutch generating industry in the coming decades, and that security of supply, efficiency, emissions and generating cost will to a large extent be determined by the gas turbine. However, the introduction of the gas turbine, driven by the possibility of high-efficiency electricity generation in e.g. combined cycle units, the increase in scale of the machines and the fact that they are increasingly being used in base load units have also led to problems and forced unavailability, as will be shown under goals of the project. The problems are related to creep, thermal stresses and fatigue of combustion chambers, turbine rotor blades, rotors etc. Apart from these problem areas, other subjects of interest are optimization of inlet air filtering and compressor cleaning. It is the Dutch Electricity Production industry who realized that a substantial R&D effort is necessary to solve those user related problems and formulated the execution of the target project Gas Turbines.

scholarly journals Thermoeconomic Optimization of Steam Pressure of Heat Recovery Steam Generator in Combined Cycle Gas Turbine under Different Operation Strategies

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4991
Author(s):  
Zhen Wang ◽  
Liqiang Duan
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Steam Pressure ◽  
Pressure Level ◽  
Combined Cycle ◽  
Load Rate ◽  
Generation Cost ◽  
System Power

The optimization of the steam parameters of the heat recovery steam generators (HRSG) of Combined Cycle Gas Turbines (CCGT) has become one of the important means to reduce the power generation cost of combined cycle units. Based on the structural theory of thermoeconomics, a thermoeconomic optimization model for a triple pressure reheat HRSG is established. Taking the minimization of the power generation cost of the combined cycle system as the optimization objective, an optimization algorithm based on three factors and six levels of orthogonal experimental samples to determine the optimal solution for the high, intermediate and low pressure steam pressures under different gas turbine (GT) operation strategies. The variation law and influencing factors of the system power generation cost with the steam pressure level under all operation strategies are analyzed. The research results show that the system power generation cost decreases as the GT load rate increases, T4 plays a dominant role in the selection of the optimal pressure level for high pressure (HP) steam and, in order to obtain the optimum power generation cost, the IGV T3-650-F mode should be adopted to keep the T4 at a high level under different GT load rates.

Sign in / Sign up

Export Citation Format

Share Document