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.

scholarly journals Gas Turbines - Major Greenhouse Gas Inhibitors

2015 ◽  
Vol 137 (12) ◽  
pp. 54-55
Author(s):  
Lee S. Langston
Keyword(s):  
Natural Gas ◽  
Greenhouse Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Hydrocarbon Fuel ◽  
Gas Production ◽  
Combined Cycle

This article explains how combined cycle gas turbine (CCGT) power plants can help in reducing greenhouse gas from the atmosphere. In the last 25 years, the development and deployment of CCGT power plants represent a technology breakthrough in efficient energy conversion, and in the reduction of greenhouse gas production. Existing gas turbine CCGT technology can provide a reliable, on-demand electrical power at a reasonable cost along with a minimum of greenhouse gas production. Natural gas, composed mostly of methane, is a hydrocarbon fuel used by CCGT power plants. Methane has the highest heating value per unit mass of any of the hydrocarbon fuels. It is the most environmentally benign of fuels, with impurities such as sulfur removed before it enters the pipeline. If a significant portion of coal-fired Rankine cycle plants are replaced by the latest natural gas-fired CCGT power plants, anthropogenic carbon dioxide released into the earth’s atmosphere would be greatly reduced.

Repowering: An Option for Refurbishment of Old Thermal Power Plants in Latin-American Countries

2010 ◽  
Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa ◽  
Luiz Augusto Horta Nogueira ◽  
Electo E. Silva Lora
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Power Plants ◽  
Thermal Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Fuel Oil ◽  
Thermal Power Plants

The operational rules for the electricity markets in Latin America are changing at the same time that the electricity power plants are being subjected to stronger environmental restrictions, fierce competition and free market rules. This is forcing the conventional power plants owners to evaluate the operation of their power plants. Those thermal power plants were built between the 1960’s and the 1990’s. They are old and inefficient, therefore generating expensive electricity and polluting the environment. This study presents the repowering of thermal power plants based on the analysis of three basic concepts: the thermal configuration of the different technological solutions, the costs of the generated electricity and the environmental impact produced by the decrease of the pollutants generated during the electricity production. The case study for the present paper is an Ecuadorian 73 MWe power output steam power plant erected at the end of the 1970’s and has been operating continuously for over 30 years. Six repowering options are studied, focusing the increase of the installed capacity and thermal efficiency on the baseline case. Numerical simulations the seven thermal power plants are evaluated as follows: A. Modified Rankine cycle (73 MWe) with superheating and regeneration, one conventional boiler burning fuel oil and one old steam turbine. B. Fully-fired combined cycle (240 MWe) with two gas turbines burning natural gas, one recuperative boiler and one old steam turbine. C. Fully-fired combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. D. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler and one old steam turbine. The gas turbine has water injection in the combustion chamber. E. Fully-fired combined cycle (242 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners and one old steam turbine. The gas turbine has steam injection in the combustion chamber. F. Hybrid combined cycle (235 MWe) with one gas turbine burning natural gas, one recuperative boiler with supplementary burners, one old steam boiler burning natural gas and one old steam turbine. G. Hybrid combined cycle (235 MWe) with one gas turbine burning diesel fuel, one recuperative boiler with supplementary burners, one old steam boiler burning fuel oil and one old steam turbine. All the repowering models show higher efficiency when compared with the Rankine cycle [2, 5]. The thermal cycle efficiency is improved from 28% to 50%. The generated electricity costs are reduced to about 50% when the old power plant is converted to a combined cycle one. When a Rankine cycle power plant burning fuel oil is modified to combined cycle burning natural gas, the CO2 specific emissions by kWh are reduced by about 40%. It is concluded that upgrading older thermal power plants is often a cost-effective method for increasing the power output, improving efficiency and reducing emissions [2, 7].

Development and Implementation of Repair Processes for Refurbishment of W501F, Row 1 Turbine Blades

2001 ◽  
Author(s):  
Richard Curtis ◽  
Warren Miglietti ◽  
Michael Pelle
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Cycle Basis ◽  
Repair Procedure ◽  
Crack Repair ◽  
Maintenance Requirements

In recent years, orders for new land-based gas turbines have skyrocketed, as the planning, construction and commissioning of new power plants based on combined-cycle technology advances at an unprecedented pace. It is estimated that 65–70% of these new equipment orders is for high-efficiency, advanced “F”, “G” or “H” class machines. The W501F/FC/FD gas turbine, an “F” class machine currently rated at 186.5 MW (simple cycle basis), has entered service in significant numbers. It is therefore of prime interest to owners/operators of this gas turbine to have sound component refurbishment capabilities available to support maintenance requirements. Processes to refurbish the Row 1 turbine blade, arguably the highest “frequency of replacement” component in the combustion and hot sections of the turbine, were recently developed. Procedures developed include removal of brazed tip plates, coating removal, rejuvenation heat treatment, full tip replacement utilizing electron beam (EB) and automated micro-plasma transferred arc (PTA), joining methods, proprietary platform crack repair and re-coating. This paper describes repair procedure development and implementation for each stage of the process, and documents the metallurgical and mechanical characteristics of the repaired regions of the component.

Electrical Power Generation: Fossil Fuels

2017 ◽  
Author(s):  
Peter Rez
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Power Plants ◽  
Fossil Fuels ◽  
Turbine Blades ◽  
Electrical Power ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Steam Temperature

Nearly all electrical power is generated by rotating a coil in a magnetic field. In most cases, the coil is turned by a steam turbine operating according to the Rankine cycle. Water is boiled and heated to make high-pressure steam, which drives the turbine. The thermal efficiency is about 30–35%, and is limited by the highest steam temperature tolerated by the turbine blades. Alternatively, a gas turbine operating according to the Brayton cycle can be used. Much higher turbine inlet temperatures are possible, and the thermal efficiency is higher, typically 40%. Combined cycle generation, in which the hot exhaust from a gas turbine drives a Rankine cycle, can achieve thermal efficiencies of almost 60%. Substitution of coal-fired by combined cycle natural gas power plants can result in significant reductions in CO2 emissions.

Industrial Users Choose Fuel Flexible GT11N2 for Burning Blast Furnace Gas in Combined Cycle Power Plants

1997 ◽  
Author(s):  
G. Gnädig ◽  
K. Reyser ◽  
W. Fischer ◽  
J. Schmidli
Keyword(s):  
Blast Furnace ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Environmental Regulations ◽  
Thermal Power ◽  
Combined Cycle ◽  
Thermal Power Plants ◽  
Industrial Plants ◽  
Blast Furnace Gas

Stricter environmental regulations and the need for high-efficiency energy generation have led an increasing number of industrial users to investigate alternatives to burning waste gases from the industrial plants in conventional thermal power plants. Combined cycle power plants using gas turbines capable of burning low-caloric fuels such as blast furnace gas can meet these requirements with thermal efficiencies of more than 45%.

Aerodynamic Turbine Design for an Oxy-Fuel Combined Cycle

2016 ◽  
Author(s):  
Adrian Dahlquist ◽  
Magnus Genrup
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Power ◽  
Design Methods ◽  
Combined Cycle ◽  
Working Fluid ◽  
3D Analysis ◽  
Conventional Design ◽  
Turbine Design

The oxy-fuel combined cycle (OCC) is one of several carbon capture and sequestration (CCS) technologies being developed to reduce CO2 emissions from thermal power plants. The OCC consists of a semi-closed topping Bryton cycle, and a traditional bottoming Rankine cycle. The topping cycle operates with a working medium mixture of mainly CO2 and H2O. This CO2-rich working fluid has significantly different gas properties compared to a conventional open gas turbine cycle, which thereby affects the aerodynamic turbine design for the gas turbine units. The aerodynamic turbine design for oxy-fuel gas turbines is an unexplored research field. The topic of this study was therefore to investigate the aerodynamic turbine design of turbines operating with a CO2-rich working fluid. The investigation was performed through a typical turbine aero-design loop, which covered the 1D mid-span, 2D through-flow, 3D blade profiling design and the steady-state 3D analysis. The design was performed through the use of conventional design methods and criteria in order to investigate if any significant departures from conventional turbine design methods were required. The survey revealed some minor deviations in design considerations, yet it showed that the design is feasible with today’s state-of-the-art technology by using conventional design practice and methods. The performance of the oxy-fuel combined cycle was revised based on the performance figures from the components design. The expected total performance figures for the oxy-fuel combined cycle were calculated to be a net electrical power of 119.9 MW and a net thermal efficiency of 48.2%. These figures include the parasitic consumption for the oxygen production required for the combustion and the CO2 compression of the CO2 bleed stream.

A Thermo-Economic Study of Storage Integration in Hybrid Solar Gas-Turbine Power Plants

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
James Spelling ◽  
Rafael Guédez ◽  
Björn Laumert
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Thermal Power ◽  
Storage Unit ◽  
Electricity Cost ◽  
Trade Offs ◽  
Conflicting Objectives ◽  
Industrial Gas Turbines

A thermo-economic simulation model of a hybrid solar gas-turbine (HSGT) power plant with an integrated storage unit has been developed, allowing determination of the thermodynamic and economic performance. Designs were based around two representative industrial gas-turbines: a high efficiency machine and a low temperature machine. In order to examine the trade-offs that must be made, multi-objective thermo-economic analysis was performed, with two conflicting objectives: minimum investment costs and minimum specific carbon dioxide (CO2) emissions. It was shown that with the integration of storage, annual solar shares above 85% can be achieved by HSGT systems. The levelized electricity cost (LEC) for the gas-turbine system as this level of solar integration was similar to that of parabolic trough plants, allowing them to compete directly in the solar power market. At the same time, the water consumption of the gas-turbine system is significantly lower than contemporary steam-cycle based solar thermal power plants.

Commercialization and Fleet Experience of the 7/9HA Gas Turbine Combined Cycle

2019 ◽  
Author(s):  
Christian Vandervort ◽  
David Leach ◽  
David Walker ◽  
Jerry Sasser
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Operating Experience ◽  
Combined Cycle ◽  
Lessons Learned ◽  
Operational Flexibility ◽  
Industrial Gas Turbine ◽  
Cycle Efficiency

Abstract The power generation industry is facing unprecedented challenges. High fuel costs and increased penetration of renewable power have resulted in greater demand for high efficiency and operational flexibility. Imperatives to reduce carbon footprint place an even higher premium on efficiency. Power producers are seeking highly efficient, reliable, and operationally flexible solutions that provide long-term profitability in a volatile environment. New generation must also be cost-effective to ensure affordability for both domestic and industrial consumers. Gas turbine combined cycle power plants meet these requirements by providing reliable, dispatchable generation with a low cost of electricity, reduced environmental impact, and broad operational flexibility. Start times for large, industrial gas turbine combined cycles are less than 30 minutes from turning gear to full load, with ramp rates from 60 to 88 MW/minute. GE introduced the 7/9HA industrial gas turbine product portfolio in 2014 in response to these demands. These air-cooled, H-class gas turbines (7/9HA) are engineered to achieve greater than 63% net combined cycle efficiency while delivering operational flexibility through deep, emission-compliant turndown and high ramp rates. The largest of these gas turbines, the 9HA.02, is designed to exceed 64% combined cycle efficiency (net, ISO) in a 1×1, single-shaft (SS) configuration. As of December 2018, a total of 32 7/9HA power plants have achieved COD (Commercial Operation Date) while accumulating over 220,000 hours of operation. These plants operate across a variety of demand profiles including base load and load following (intermediate) service. Fleet leaders for both the 7HA and 9HA have exceeded 12,000 hours of operation, with multiple units over 8,000 hours. This paper will address four topics relating to the HA platform: 1) gas turbine product technology, 2) gas turbine validation, 3) integrated power plant commissioning and operating experience, and 4) lessons learned and fleet reliability.

Addressing the Energy Trilemma With LPG-Fuelled, Water-Free Combined Cycle Power Plants

2020 ◽  
Author(s):  
Michael Welch
Keyword(s):  
Environmental Impact ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Gas Production ◽  
Combined Cycle ◽  
Liquefied Petroleum Gas ◽  
Distributed Power ◽  
The Impact

Abstract Many parts of the world are facing the triple challenge of providing secure energy to fuel economic growth at an affordable cost while minimizing the impact of energy production on the environment. Island nations especially struggle to address this trilemma, as renewable resources are usually limited and fossil fuels imported. Traditionally such distributed power plants have relied on liquid fuels and multiple open cycle reciprocating engines to provide both redundancy and the ability to load follow across a broad load range to maximize efficiency. This approach has created high electricity prices and significant negative environmental impact, especially that attributed to CO2, NOx, and SOx. With increasing natural gas production, the availability of Liquefied Petroleum Gas (LPG) has grown, and costs have fallen, allowing the potential to switch from fuel oils to LPG to reduce environmental impacts. Energy costs and environmental impact can be further reduced by using high efficiency Gas Turbine Combined Cycle plants with dry low emissions combustion technology. However, a further hurdle facing many locations is lack of the fresh water required for combined cycle operations. LPG-fuelled Gas Turbine Combined Cycle using Organic Rankine Cycle (ORC) technology can address all aspects of this energy trilemma. This paper reviews the conceptual design of a proposed 100MW distributed power plant for an island location, based on multiple LPG-fuelled gas turbines to follow load demand, with an ORC bottoming cycle to maximize efficiency.

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.

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