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.

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.

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.

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.”

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.

Cogenerative Performance of a Wind–Gas Turbine–Organic Rankine Cycle Integrated System for Offshore Applications

2016 ◽  
Author(s):  
Michele Bianchi ◽  
Lisa Branchini ◽  
Andrea De Pascale ◽  
Francesco Melino ◽  
Valentina Orlandini ◽  
...  
Keyword(s):  
Power System ◽  
Gas Turbines ◽  
Oil And Gas ◽  
High Reliability ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Combined Heat And Power ◽  
Combined Cycle ◽  
Integrated System ◽  
Offshore Wind

Gas Turbines (GT) are widely used for power generation in offshore oil and gas facilities, due to their high reliability, compactness and dynamic response capabilities. Small heavy duty and aeroderivative units in multiple arrangements are typically used to offer larger load flexibility, but limited efficiency of such machines is the main drawback. A solution to enhance the system performance, also in Combined Heat and Power (CHP) arrangement, is the implementation of Organic Rankine Cycle (ORC) systems at the bottom of the gas turbines. Moreover, the resulting GT-ORC combined cycle could be further integrated with additional renewable sources. Offshore wind technology is rapidly developing and floating wind turbines could be combined with offshore GT-ORC based power plants to satisfy the platform load. The pioneering stand alone power system, for an oil and gas platform, examined in this paper comprises a 10MW offshore wind farm and three gas turbines rated for 16.5MW, each one coupled with an 4.5MW ORC module. The ORC main parameters are observed under different wind power fluctuations. Due to the non-programmable availability of wind and power demand, the part-load and dynamic characteristics of the system should be investigated. A dynamic model of the power system based on first principles is used, developed in the Modelica language. The model is integrated with a time series-based model of two offshore wind mills. Various thermodynamic indexes, available in the literature, are identified and evaluated to compare the actual combined heat and power performances of single components and of the overall integrated system in the considered wind scenarios.

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.

Modified Rankine HRSG Beats Triple-Pressure System

1996 ◽  
Author(s):  
Peter Eisenkolb ◽  
Martin Pogoreutz ◽  
Hermann Halozan
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Fossil Fuels ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Pressure System ◽  
Exergy Losses

Gas-fired combined cycle power plants (CCP) are presently the most efficient systems for producing electricity with fossil fuels. Gas turbines have been and are being improved remarkably during the last years; presently they achieve efficiencies of more than 38% and gas turbine outlet temperatures of up to 610°C. These high outlet temperatures require modifications and improvements of heat recovery steam generators (HRSG). Presently dual pressure HRSGs are most commonly used in combined cycle power stations. The next step seems to be the triple-pressure HRSG to be able to utilise the high gas turbine outlet temperatures efficiently and to reduce exergy losses caused by the heat transfer between exhaust gas and the steam cycle. However, such triple-pressure systems are complicated considering parallel tube bundles as well as start up operation and load changes. For that reason an attempt has been made to replace such multiple pressure systems by a modified Rankine cycle with only a single-pressure level. In the case of the same total heat transfer surfaces this innovative single-pressure system achieves approximately the same efficiency as the triple-pressure system. By optimising the heat recovery from the exhaust gas to the steam/water cycle, i.e. minimising exergy losses, the stack temperature is much higher. Increasing the heat transfer surfaces means a decrease of the stack temperature and a further improvement of the overall CCP-efficiency. Therefore one has to be aware that the proposed system offers advantages not only in the case of a foreseeable increase of gas turbine outlet temperatures but also for presently available gas turbines. Using existing highly efficient gas turbines and subcritical steam conditions, power plants with this proposed Eisenkolb Single Pressure (ESP_CCP) heat recovery steam generator achieve thermal efficiencies of about 58.7% (LHV).

Hot Windbox and Combined Cycle Repowering to Improve Heat Rate

2010 ◽  
Author(s):  
Tarek A. Tawfik ◽  
Thomas P. Smith
Keyword(s):  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Heat Rate ◽  
The United States ◽  
Combined Cycle ◽  
Plant Performance ◽  
Ambient Conditions ◽  
North East

Retrofitting existing power generation plants by repowering is becoming an attractive option to improve plant performance with less cost. “Hot Windbox Repowering” involves utilizing the hot exhaust gas from a combustion gas turbine and using it as combustion air for an existing fossil-fuel boiler. “Combined Cycle Repowering” or “Full Repowering” involves completely replacing the existing boiler with a combined cycle consisting of a gas turbine(s) and a heat recovery steam generator (HRSG). The existing steam turbine will be used in both repowering scenarios. This paper discusses an engineering study and summarizes the results obtained from repowering an existing heavy-oil / natural gas fired steam power plant in the north east of the United States. The plant consists of a 600 MW boiler and steam turbine. Several engineering studies were considered and evaluated thermodynamically and economically to retrofit such plant. Several options were considered involving different gas turbines, gas turbine combinations, and different repowering methods. The best option is based on retrofitting the unit by a combination of both, hot windbox repowering and combined cycle repowering. The proposed design consists of one gas turbine repowering the windbox of the existing boiler, and a second gas turbine operating in a separate combined cycle configuration with the generated superheated steam tying into the main steam line and expanding in the existing steam turbine. Several heat balances were developed to assist in obtaining meaningful results for this feasibility study. Actual costs were obtained for the gas turbines and heat recovery steam generators (HRSG), as well as installation costs for a more accurate evaluation. The results indicate that the combined output of the repowered unit will generate an additional 295 MW and reduce the heat rate by more than 11 percent at full load and annual average ambient conditions. The estimated capital cost of the project is expected to range from $235 to $245 millions.

Advanced Combined Cycle Alternatives With the Latest Gas Turbines

1996 ◽  
Author(s):  
P. J. Dechamps
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Heat Recovery ◽  
Power Plants ◽  
Combined Cycle ◽  
Point Of View ◽  
Specific Work ◽  
Turbine Cooling ◽  
Exhaust Temperature ◽  
Industrial Gas Turbine

The last decade has seen remarkable improvements in industrial gas turbine size and performances. There is no doubt that the coming years are holding the promises of even more progress in these fields. As a consequence, the fuel utilization achieved by combined cycle power plants has been steadily increased. This is however also because of the developments in the heat recovery technology. Advances on the gas turbine side justify the development of new combined cycle schemes, with more advanced heat recovery capabilities. Hence, the system performance is spiralling upwards. In this paper, we look at some of the heat recovery possibilities with the newly available gas turbine engines, characterized by a high exhaust temperature, a high specific work, and the integration of some gas turbine cooling with the boiler. The schemes range from classical dual pressure systems, to triple pressure systems with reheat in supercritical steam conditions. For each system, an optimum set of variables (steam pressures, etc) is proposed. The effect of some changes on the steam cycle parameters, like increasing the steam temperatures above 570°C are also considered. Emphasis is also put on the influence of some special features or arrangements of the heat recovery steam generators, not only from a thermodynamic point of view.

Nuclear Gas Turbines: Small-Scale Inherently Safe, Well-Proven Nuclear Power

2002 ◽  
Author(s):  
H. van Dam ◽  
T. H. J. J. van der Hagen
Keyword(s):  
Power Generation ◽  
Energy Conversion ◽  
Gas Turbine ◽  
Heat Production ◽  
Gas Turbines ◽  
Nuclear Power ◽  
Combined Heat And Power ◽  
Electricity Production ◽  
Small Scale ◽  
Prime Mover

The paper discusses uranium as a new fuel for gas turbines used as energy conversion installations for the markets of: stand-alone heat production, combined heat and power generation, stand-alone electricity production and as prime mover on board ships. This development is a logical step in a historical trend in energy conversion. The paper discusses the availability of the fuel, uranium and the construction of the fuel which makes this combination of gas turbine and uranium suitable for the non-utility markets.

Sign in / Sign up

Export Citation Format

Share Document