Comparison of Externally Fired and Internal Combustion Gas Turbines Using Biomass Fuel

2001 ◽  
Vol 123 (4) ◽  
pp. 291-296 ◽  
Author(s):  
Sandro B. Ferreira ◽  
Pericles Pilidis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Internal Combustion ◽  
Combined Cycle ◽  
Maintenance Cost ◽  
Combustion Gas ◽  
Exhaust Temperature ◽  
Exergetic Analysis ◽  
Main Components

There is a difference of opinion regarding the relative merits of gas turbines using biomass fuels. Some engineers believe that the internal combustion gas turbine coupled to a gasifier will give a higher efficiency than the externally fired gas turbine using pretreated biomass that is not gasified. Others believe the opposite. In this paper, a comparison between these schemes is made, within the framework of the Brazilian perspective. The exergetic analysis of four cycles is described. The first cycle is externally fired (EFGT), the second uses gasified biomass as fuel (BIG/GT), each of them with a combined cycle as a variant (EFGT/CC and BIG/GTCC). These four are then compared to the natural gas turbine cycles (NGT and NGT/CC) in order to evaluate the thermodynamic cost of using biomass. The comparison is carried out in terms of thermal efficiency and in terms of exergetic efficiency and exergy destruction in the main components. The present analysis shows that the EFGT is quite promising. When compared to the NGT cycle, the EFGT gas turbine shows poor efficiency, though this parameter practically equals that of the BIG/GT cycle. The use of a bottoming steam cycle changes the figures, and the EFGT/CC—due to its higher exhaust temperature—results in high efficiency compared to the BIG/GTCC. Its lower initial and maintenance cost may be an important attraction.

scholarly journals Perspective on a Combustion-Free Gas Turbine to Meet Power Generation Needs in the 21st Century

1997 ◽  
Author(s):  
Colin F. McDonald
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
21St Century ◽  
Gas Turbines ◽  
High Efficiency ◽  
Electrical Power ◽  
Resource Depletion ◽  
Combined Cycle ◽  
Combustion Gas

The combustion gas turbine, operating in both simple and combined cycle modes, is rapidly becoming the preferred prime-mover for electrical power generation for both new plants, and in the repowering of old power stations. In replacing Rankine cycle plants the combustion gas turbine could become dominant in the power generation field early in the next century. Fired currently with natural gas, and later with gasified coal these gas turbines will operate for many decades with no concern about resource depletion. This paper addresses an extension of high efficiency gas turbine technology but uses a combustion and emission-free heat source, namely a high temperature gas cooled nuclear reactor. The motivation for this evolution is essentially twofold, 1) to introduce an environmentally benign plant that does not emit greenhouse gases, and 2) provide electrical power to nations that have no indigenous natural gas or coal supplies. This paper presents a confidence-building approach that eliminates risk towards the goal of making the nuclear gas turbine a reality in the 21st century.

Performance Analysis of a Combined Cycle Power Plant Through Exergetic and Environmental Indices

2017 ◽  
Author(s):  
Edgar Vicente Torres González ◽  
Raúl Lugo Leyte ◽  
Martín Salazar Pereyra ◽  
Helen Denise Lugo Méndez ◽  
Miguel Toledo Velázquez ◽  
...  
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Environmental Indices ◽  
Combined Cycle Power Plant ◽  
Combustion Gases ◽  
Combined Cycle Plant ◽  
Exergetic Analysis ◽  
Gas Turbine Power Plant

In this paper is carried out a comparison between a gas turbine power plant and a combined cycle power plant through exergetic and environmental indices in order to determine performance and sustainability aspects of a gas turbine and combined cycle plant. First of all, an exergetic analysis of the gas turbine and the combined is carried out then the exergetic and environmental indices are calculated for the gas turbine (case A) and the combined cycle (case B). The exergetic indices are exergetic efficiency, waste exergy ratio, exergy destruction factor, recoverable exergy ratio, environmental effect factor and exergetic sustainability. Besides, the environmental indices are global warming, smog formation and acid rain indices. In the case A, the two gas turbines generate 278.4 MW; whereas 415.19 MW of electricity power is generated by the combined cycle (case B). The results show that exergetic sustainability index for cases A and B are 0.02888 and 0.1058 respectively. The steam turbine cycle improves the overall efficiency, as well as, the reviewed exergetic indexes. Besides, the environmental indices of the gas turbines (case A) are lower than the combined cycle environmental indices (case B), since the combustion gases are only generated in the combustion chamber.

Gas Turbine Exhaust Expansion Joints, Diverter and Damper Designs for the New Generation of Higher Temperature, High Efficiency Gas Turbines

1989 ◽  
Author(s):  
Lothar Bachmann ◽  
W. Fred Koch
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Operating Conditions ◽  
High Mass ◽  
Expansion Joints ◽  
Gas Turbine Exhaust ◽  
New Generation ◽  
Turbine Exhaust

The purpose of this paper is to update the industry on the evolutionary steps that have been taken to address higher requirements imposed on the new generation combined cycle gas turbine exhaust ducting expansion joints, diverter and damper systems. Since the more challenging applications are in the larger systems, we shall concentrate on sizes from nine (9) square meters up to forty (40) square meters in ducting cross sections. (Reference: General Electric Frame 5 through Frame 9 sizes.) Severe problems encountered in gas turbine applications for the subject equipment are mostly traceable to stress buckling caused by differential expansion of components, improper insulation, unsuitable or incompatible mechanical design of features, components or materials, or poor workmanship. Conventional power plant expansion joints or dampers are designed for entirely different operating conditions and should not be applied in gas turbine applications. The sharp transients during gas turbine start-up as well as the very high temperature and high mass-flow operation conditions require specific designs for gas turbine application.

Performance and Cost Analysis of Advanced Gas Turbine Cycles With Precombustion CO2 Capture

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Stéphanie Hoffmann ◽  
Michael Bartlett ◽  
Matthias Finkenrath ◽  
Andrei Evulet ◽  
Tord Peter Ursin
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Co2 Separation ◽  
The Cost

This paper presents the results of an evaluation of advanced combined cycle gas turbine plants with precombustion capture of CO2 from natural gas. In particular, the designs are carried out with the objectives of high efficiency, low capital cost, and low emissions of carbon dioxide to the atmosphere. The novel cycles introduced in this paper are comprised of a high-pressure syngas generation island, in which an air-blown partial oxidation reformer is used to generate syngas from natural gas, and a power island, in which a CO2-lean syngas is burnt in a large frame machine. In order to reduce the efficiency penalty of natural gas reforming, a significant effort is spent evaluating and optimizing alternatives to recover the heat released during the process. CO2 is removed from the shifted syngas using either CO2 absorbing solvents or a CO2 membrane. CO2 separation membranes, in particular, have the potential for considerable cost or energy savings compared with conventional solvent-based separation and benefit from the high-pressure level of the syngas generation island. A feasibility analysis and a cycle performance evaluation are carried out for large frame gas turbines such as the 9FB. Both short-term and long-term solutions have been investigated. An analysis of the cost of CO2 avoided is presented, including an evaluation of the cost of modifying the combined cycle due to CO2 separation. The paper describes a power plant reaching the performance targets of 50% net cycle efficiency and 80% CO2 capture, as well as the cost target of 30$ per ton of CO2 avoided (2006 Q1 basis). This paper indicates a development path to this power plant that minimizes technical risks by incremental implementation of new technology.

scholarly journals High Efficiency-Coal and Gas (HE-C&G): An Advanced Hybrid Power Plant Concept With Sequential Combustion Gas Turbines GT24/GT26

1997 ◽  
Author(s):  
Mircea Fetescu
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combustion Gas ◽  
Hybrid Power ◽  
Wide Range ◽  
Hybrid Power Plant ◽  
Very High

The High Efficiency-Coal and Gas (HE-C&G) is a hybrid power plant concept integrating Conventional Steam Power Plants (CSPP) and gas turbine / combined cycle plants. The gas turbine exhaust gas energy is recovered in the HRSG providing partial condensate and feedwater preheating and generating steam corresponding to the main boiler live steam conditions (second steam source for the ST). The concept, exhibiting very high design flexibility, integrates the high performance Sequential Combustion gas turbines GT24/GT26 technology into a wide range of existing or new CSPP. Although HE-C&G refers to coal as the most abundant fossil fuel resource, oil or natural gas fired steam plants could be also designed or converted following the same principle. The HE-C&G provides very high marginal efficiencies on natural gas, up to and above 60%, very high operating and dispatching flexibility and on-line optimization of fuel and O&M costs at low capital investment. This paper emphasizes the operating flexibility and resulting benefits, recommending the HE-C&G as one of the most profitable options for generating power especially for conversion of existing CSPP with gas turbines.

scholarly journals Gas Turbine Topping Stage Based on Energy Exchangers: Process and Performance

1993 ◽  
Author(s):  
Erwin Zauner ◽  
Yau-Pin Chyou ◽  
Frederic Walraven ◽  
Rolf Althaus
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Operating Cost ◽  
Combined Cycle ◽  
Specific Power ◽  
Material Strength ◽  
Nox Emissions ◽  
Gas Temperature ◽  
And Performance

Power generation in gas turbines is facing three main challenges today: • Low pollution prescribed by legal requirements. • High efficiency to obtain low operating cost and low CO2 emissions. • High specific power output to obtain low product and installation cost. Unfortunately, some of these requirements are contradictory: high efficiency and specific power force the development towards higher temperatures and pressures which increase NOx emissions and intensify the cooling and material strength problems. A breakthrough can be achieved by applying an energy exchanger as a topping stage. Inherent advantages are the self-cooled cell-rotor which can be exposed to much higher gas temperature than a steady-flow turbine and a very short residence time at peak temperature which keeps NOx emissions under control. The basic idea has been proposed long time ago. Fundamental research has now led to a new energy exchanger concept. Key issues include symmetric pressure-wave processes, partial suppression of flow separation and fluid mixing, as well as quick afterburning in premixed mode. The concept has been proven in a laboratory-scale engine with very promising results. The application of an energy exchanger as a topping stage onto existing gas turbines would increase the efficiency by 17% (relative) and the power by 25%. Since the temperature level in the turbine remains unchanged, the performance improvement can also be fully utilized in combined cycle applications. This process indicates great potentials for developing advanced gas turbine systems as well as for retrofitting existing ones.

The Energy Exchanger, a New Concept for High-Efficiency Gas Turbine Cycles

1967 ◽  
Vol 89 (2) ◽  
pp. 217-227 ◽  
Author(s):  
R. C. Weatherston ◽  
A. Hertzberg
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Exchange ◽  
High Efficiency ◽  
Inlet Temperature ◽  
Viscous Effects ◽  
Isentropic Compression ◽  
Combustion Gas ◽  
Power Cycles ◽  
Compression Waves

A method of circumventing the turbine inlet temperature limitation of present-day gas turbines is presented. This method is based on a direct fluid-to-fluid energy exchanger whereby the available energy of expansion of the hot combustion gas in a gas turbine cycle is transferred directly to a colder gas. The aerodynamic wave processes in several possible modes of operation are examined to determine the inherent limitations in efficiency of direct fluid-to-fluid energy exchange processes. In particular, it is demonstrated that, by using a system of isentropic compression waves to avoid shock losses and by carefully choosing the molecular weights of the fluids utilized in the energy exchanger, perfect energy exchange is possible in principle. When allowances are made for losses due to mixing, leakage, and viscous effects, an energy exchanger utilizing heated combustion air at 3240 deg F to drive steam at 1500 deg F with a potential energy exchange efficiency of 85 percent is feasible. Applications of the air-steam energy exchanger operating in gas turbine cycles utilizing a conservative choice of component efficiencies indicate that thermal efficiencies of gas turbine power cycles of 50–60 percent may be possible.

Design and Validation of a Compressor for a New Generation of Heavy-Duty Gas Turbines

2007 ◽  
Author(s):  
F. Eulitz ◽  
B. Kuesters ◽  
F. Mildner ◽  
M. Mittelbach ◽  
A. Peters ◽  
...  
Keyword(s):  
Power Plant ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
High Efficiency ◽  
Forced Response ◽  
Combined Cycle ◽  
Test Facility ◽  
Primary Driver ◽  
Compressor Technology

Siemens H-Class. Siemens has developed the world-largest H-class Gas Turbine (SGT™) that sets unparalleled standards for high efficiency, low life cycle costs and operating flexibility. With a power output of 340+ MW, the SGT5–8000H gas turbine will be the primary driver of the new Siemens Combined Cycle Power Plant (SCC™) for the 50 Hz market, the SCC5–8000H, with an output of 530+ MW at more than 60% efficiency. After extensive lab and component testing, the prototype has been shipped to the power plant for an 18-month validation phase. In this paper, the compressor technology, which was developed for the Siemens H-class, is presented through its development and validation phases. Reliability and Availability. The compressor has been extensively validated in the Siemens Berlin Test Facility during consecutive engine test programs. All key parameters, such as mass flow, operating range, efficiency and aero mechanical behavior meet or exceed expectations. Six-sigma methodology has been exploited throughout the development to implement the technologies into a robust design. Efficiency. The new compressor technology applies the Siemens advanced aerodynamics design methodology based on the high performance airfoil (HPA) systematic which leads to broader operation range and higher efficiency than a standard controlled diffusion airfoil (CDA) design. Operational Flexibility. The compressor features an IGV and three rows of variable guide vanes for improved turndown capability and improved part load efficiency. Serviceability. The design has been optimized for serviceability and less complexity. Following the Siemens tradition, all compressor rotating blades can be replaced without rotor lift or destacking. Evolutionary Design Innovation. The compressor design incorporates the best features and experience from the operating fleets and technology innovation prepared through detailed research, analysis and lab testing in the past decade. The design tools are based on best practices from former Siemens KWU and Westinghouse with enhancements allowing for routine front-to-back compressor 3D CFD multistage analysis, unsteady blade row interaction, forced response analyses and aero-elastic analysis.

scholarly journals Whisper and Roar

2014 ◽  
Vol 136 (07) ◽  
pp. 38-43
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Marine Applications ◽  
Almost All

This article focuses on the use of gas turbines for electrical power, mechanical drive, and marine applications. Marine gas turbines are used to generate electrical power for propulsion and shipboard use. Combined-cycle electric power plants, made possible by the gas turbine, continue to grow in size and unmatched thermal efficiency. These plants combine the use of the gas turbine Brayton cycle with that of the steam turbine Rankine cycle. As future combined cycle plants are introduced, we can expect higher efficiencies to be reached. Since almost all recent and new U.S. electrical power plants are powered by natural gas-burning, high-efficiency gas turbines, one has solid evidence of their contribution to the greenhouse gas reduction. If coal-fired thermal power plants, with a fuel-to-electricity efficiency of around 33%, are swapped out for combined-cycle power plants with efficiencies on the order of 60%, it will lead to a 70% reduction in carbon emissions per unit of electricity produced.

Cycle Optimization and High Performance Analysis of Gas Engine-Gas Turbine Combined Cycles

2005 ◽  
Author(s):  
Tadashi Tsuji
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Combined Cycle ◽  
Compound System ◽  
Generation Efficiency ◽  
Engine Exhaust ◽  
Gas Engine ◽  
Exhaust Temperature

The reciprocating engine operates with a maximum pressure and temperature in its cylinders that is higher than that in conventional gas turbines. When a gas engine is integrated with a gas turbine instead of a turbocharger, it is an ETCS (Engine-Turbo Compound System). We have developed the concept of a compound system with ERGT (Engine Reheat Gas Turbine) and propose it as a system with potentially high thermal efficiency. A natural gas firing gas turbine combined cycle (CC) is selected as the standard system for a thermal power plant. A higher TIT (Turbine Inlet Temperature) of gas turbine usually enables higher power generation efficiency. Focusing on the effect of engine exhaust temperature, we found that the ETCS cycle with a ERGT has the potential to achieve higher thermal efficiency than that of a gas turbine combined cycle, with no change in TIT. An engine exhaust temperature of 1173K increases the system power generation efficiency from 46 to 50%LHV (TIT 1150°C) and 54 to 57%LHV (TIT 1350°C), respectively. The gas engine–gas turbine combined cycle has the potential to achieve a significant efficiency increase of +4.1%LHV (TIT 1150°C) and +2.8%LHV (TIT 1350°C), making it a promising system for future power plants. Efficiency is expected to be improved by +8.7% (TIT 1150°C) and +5.6% (TIT 1350°C), relatively.

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