Enhanced Fuel Flexibility and Emissions Compliance for Gas Turbines Through Model Based Controls Technology

2013 ◽  
Author(s):  
Ranjith Malapaty ◽  
Suresh M. V. J. J.
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbines ◽  
Power Plants ◽  
Power Demand ◽  
Combustion Dynamics ◽  
Fuel Flexibility ◽  
Plant Operations ◽  
Lng Fuel ◽  
Alternate Fuels

The world is facing complex and mounting environmental challenges. Increased fuel costs and increased market capacity in power generation markets is driving a transformation in power plant operations. Power plants are seeking ways to maximize revenue potential during peak conditions and minimize operational costs during off-peak conditions. Although proven natural gas reserves have increased globally by nearly 50% over the last 20 years, much of this growth has been focused in select regions and countries. In parallel to the discovery of new reserves is the increase in power demand across the globe. However, there are many regions of the globe in which power demand is not being matched by increased local supplies of natural gas, or in infrastructure required to supply natural gas to power generation assets. Given these drivers, there is growing global interest in LNG & alternate fuels. This phenomenon is driving a trend to explore the potential of using LNG fuels which can be easily transported across the globe as an alternative for power generation. In a carbon-constrained environment, the technology trend is for combustion systems capable of burning LNG fuel in combination with delivering the required operability. This paper will focus on developments in GE’s heavy duty gas turbines that enable operation on fuels with varying properties, providing fuel flexibility for sustainable power generation and better emissions compliance. GE’s turbine control system employs physics-based models of gas turbine operability boundaries (e.g., emissions, combustion dynamics, etc.), to continuously estimate current boundary levels and make adjustments as required.

Sequential Combustion in Ansaldo Energia Gas Turbines: The Technology Enabler for CO2-Free, Highly Efficient Power Production Based on Hydrogen

2020 ◽  
Author(s):  
Andrea Ciani ◽  
John P. Wood ◽  
Anders Wickström ◽  
Geir J. Rørtveit ◽  
Rosetta Steeneveldt ◽  
...  
Keyword(s):  
Power Generation ◽  
Free Energy ◽  
Gas Turbines ◽  
Carbon Capture ◽  
Power Plants ◽  
Carbon Capture And Storage ◽  
Combined Cycle ◽  
Fuel Flexibility ◽  
Combustion Technology ◽  
And Storage

Abstract Today gas turbines and combined cycle power plants play an important role in power generation and in the light of increasing energy demand, their role is expected to grow alongside renewables. In addition, the volatility of renewables in generating and dispatching power entails a new focus on electricity security. This reinforces the importance of gas turbines in guaranteeing grid reliability by compensating for the intermittency of renewables. In order to achieve the Paris Agreement’s goals, power generation must be decarbonized. This is where hydrogen produced from renewables or with CCS (Carbon Capture and Storage) comes into play, allowing totally CO2-free combustion. Hydrogen features the unique capability to store energy for medium to long storage cycles and hence could be used to alleviate seasonal variations of renewable power generation. The importance of hydrogen for future power generation is expected to increase due to several factors: the push for CO2-free energy production is calling for various options, all resulting in the necessity of a broader fuel flexibility, in particular accommodating hydrogen as a future fuel feeding gas turbines and combined cycle power plants. Hydrogen from methane reforming is pursued, with particular interest within energy scenarios linked with carbon capture and storage, while the increased share of renewables requires the storage of energy for which hydrogen is the best candidate. Compared to natural gas the main challenge of hydrogen combustion is its increased reactivity resulting in a decrease of engine performance for conventional premix combustion systems. The sequential combustion technology used within Ansaldo Energia’s GT36 and GT26 gas turbines provides for extra freedom in optimizing the operation concept. This sequential combustion technology enables low emission combustion at high temperatures with particularly high fuel flexibility thanks to the complementarity between its first stage, stabilized by flame propagation and its second (sequential) stage, stabilized by auto-ignition. With this concept, gas turbines are envisaged to be able to provide reliable, dispatchable, CO2-free electric power. In this paper, an overview of hydrogen production (grey, blue, and green hydrogen), transport and storage are presented targeting a CO2-free energy system based on gas turbines. A detailed description of the test infrastructure, handling of highly reactive fuels is given with specific aspects of the large amounts of hydrogen used for the full engine pressure tests. Based on the results discussed at last year’s Turbo Expo (Bothien et al. GT2019-90798), further high pressure test results are reported, demonstrating how sequential combustion with novel operational concepts is able to achieve the lowest emissions, highest fuel and operational flexibility, for very high combustor exit temperatures (H-class) with unprecedented hydrogen contents.

Past, Present and Future of Combined Cycle Power Plants: From an A/E’s Perspective

2001 ◽  
Author(s):  
Anup Singh
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Rapid Growth ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Electrical Transmission ◽  
Capital Costs ◽  
The U.S

In the 1970s, power generation from gas turbines was minimal. Gas turbines in those days were run on fuel oil, since there was a so-called “natural gas shortage”. The U.S. Fuel Use Act of 1978 essentially disallowed the use of natural gas for power generation. Hence there was no incentive on the part of gas turbine manufacturers to invest in the development of gas turbine technology. There were many regulatory developments in the 1980s and 1990s, which led to the rapid growth in power generation from gas turbines. These developments included Public Utility Regulatory Policy Act of 1978 (encouraging cogeneration), FERC Order 636 (deregulating natural gas industry), Energy Policy Act of 1992 (creating EWGs and IPPs) and FERC Order 888 (open access to electrical transmission system). There was also a backlash from excessive electric rates due to high capital recovery of nuclear and coal-fired plant costs caused by tremendous cost increase resulting from tightening NRC requirements for nuclear plants and significant SO2/NOx/other emissions controls required for coal-fired plants. During this period, rapid technology developments took place in the metallurgy, design, efficiency, and reliability of gas turbines. In addition, U.S. DOE contributed to these developments by encouraging research and development efforts in high temperature and high efficiency gas turbines. Today we are seeing a tremendous explosion of power generating facilities by electric utilities and Independent Power Producers (IPPs). A few years ago, Merchant Power (generation without power purchase agreements) was unheard of. Today it is growing at a very fast pace. Can this rapid growth be sustained? The paper will explore the factors that will play a significant role in the future growth of gas turbine-based power generation in the U.S. The paper will also discuss the methods and developments that could decrease the capital costs of gas turbine power plants resulting in the lowest cost generation compared to other power generation technologies.

Pentane Rich Fuels for Standard Siemens DLE Gas Turbines

2011 ◽  
Author(s):  
Mats Andersson ◽  
Anders Larsson ◽  
Arturo Manrique Carrera
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Special Adaptation ◽  
Fuel Flexibility ◽  
Combustion Properties ◽  
Model Substance ◽  
Wobbe Index

Associated gases at oil wells are often rich in heavy hydrocarbons (HHC, here denoting hydrocarbons heavier than propane). HHC cause handling difficulties and the combustion properties are quite different from standard natural gas. For this and other reasons HHC rich associated gases are often flared or vented. This is an enormous waste of useable energy and a significant contribution to emissions of pollutants, global CO2 and other greenhouse gases. Siemens Industrial Turbomachinery AB in Finspong (SIT AB) recently tested a standard DLE 25 MW SGT-600 gas turbine and a standard 31 MW SGT-700 gas turbine with HHC rich natural gas. Pentane was chosen as a model substance for HHC. The tested gases had up to 30% of the fuel heating value from pentane. The unmodified standard DLE gas turbines proved to be very tolerant to the tested pentane rich gases. CO emissions were reduced with increasing pentane content in the fuel for the same power output. NOx was observed to increase linearly with the pentane content. Combustion dynamics was affected mildly, but noticeably by the pentane rich fuel. This result, together with earlier presented results for the same DLE engines on nitrogen rich natural gases, gives an accepted and tested total LHV range of 25–50 MJ/kg and Wobbe index range of 25–55 MJ/Nm3. No special adaptation of the gas turbines was necessary for allowing this wide fuel range. The benefit of increased and proven fuel flexibility is obvious as it allows the gas turbine owner to make full use of opportunity fuels and to supply power at low fuel cost.

Low Load Operational Flexibility for Siemens F- and G-Class Gas Turbines

2010 ◽  
Author(s):  
Pratyush Nag ◽  
David Little ◽  
Adam Plant ◽  
Douglas Roth
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Power Demand ◽  
Operational Flexibility ◽  
Low Load ◽  
Natural Gas Prices ◽  
Carbon Dioxide Co2 ◽  
Base Load

The US gas turbine (GT) power generation market has seen significant volatility in recent years due to climate changes, changes in natural gas prices and the uncertain future of nuclear and coal power generation. Many gas turbine power plants originally intended to operate on a more continuous basis (base load) are operating in intermittent dispatch mode which has caused some operators to frequently shut down their units. This frequent cycling of units can increase start-up and maintenance costs. It could be beneficial to these plants to operate at lower loads when power demand is low and ramp up to higher loads as demand increases. A key issue in operating at lower loads is an increase in carbon monoxide (CO) emissions. When the engines are base loaded, the combustion system operates at high firing temperatures and most of the CO is oxidized to carbon dioxide (CO2). However, at part loads — when the firing temperature is lower — the CO to CO2 oxidation reaction is quenched by the cool regions near the walls of the combustion liner. This results in increased CO emissions at low loads. In order to provide greater operational flexibility to its F- & G-class gas turbine operators, Siemens has developed an upgrade for the engine system designed to allow the gas turbine to operate at lower loads while maintaining emissions. This low load turndown upgrade has been installed, tested and is currently in operation at 8 F and 4 G class Siemens operating gas turbines. These plants were previously operating typically between 70% and 100% of GT base load. Sometimes, when the demand for power was low, typically at night and on weekends, these plants would shut down. During these low power demand periods — with this upgrade installed — these plants continue to operate down to lower loads while maintaining CO emissions and with a capability to more quickly ramp-up to full load when the demand for power increases. This paper details the installation, testing results and continued validation of the Low Load Turndown upgrade.

Alternate Fuels Capability of Gas Turbines in the Process Industry

1976 ◽  
Author(s):  
W. J. Hefner
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Process Industry ◽  
Liquid Fuels ◽  
Status Report ◽  
Gasification Process ◽  
Fuel Flexibility ◽  
Combustion Properties ◽  
Performance And Emissions ◽  
Alternate Fuels

As we move into the latter 1970’s and early 1980’s, we can anticipate a period of continuing uncertainty in availability of fuel supplies for the process industry. Even though the overall picture is unclear, there are some aspects of the total problem that are predictable, with a reasonable degree of confidence. One of the developments that can be predicted on the domestic scene is the unavailability of natural gas as an industrial fuel. Short supplies of this resource have significantly limited the installation of new facilities utilizing natural gas as a fuel supply, as well as creating a need to convert existing equipment to use alternate supplies of fuel where uninterruptable sources of natural gas are no longer available. This paper discusses the fuel flexibility of heavy-duty gas turbines and is a status report on the capability of today’s equipment. In addition, techniques for evaluating alternate gas turbine fuels including requirements for cleanliness, combustion properties, physical properties, composition, performance and emissions characteristics, etc., are discussed. Fuels which are covered include: Gasification Process Derived Fuels, By-Product Gases, Distillate Oil, Crude Oil, Residual Oil, Vaporized Liquid Fuels, and Liquefied Coal Products.

Retrofittable Solutions to Keep Existing Gas Turbine Power Plants Viable and Profitable in an Increasingly Dynamic Power Generation Market: Validation of Low Pressure Drop FlameSheet™ Combustor

2019 ◽  
Author(s):  
Fred Hernandez ◽  
Hany Rizkalla
Keyword(s):  
Power Plant ◽  
Pressure Drop ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Load Range ◽  
Pressure Losses ◽  
Fuel Flexibility

Abstract As renewable energy sources continue their global energy market penetration, new natural gas fired power plant installations have decreased significantly. The reduction in new installed capacity has increased pressure on operators to profitably maintain and expand their existing fleet capability. Retrofitting existing gas turbines to increase baseload power output, expand fuel flexibility and provide a wider operating load range are key natural gas fired power plant market demands. The FlameSheet™ combustor system addresses these considerations with a novel “dual-zone burn system” design that reduces emissions, increases fuel flexibility and reduces pressure losses to improve thermal cycle efficiency. The present work presents the results of FlameSheet™ installations into GE 7F.03 heavy duty gas turbines at two commercial sites. The first installation combined FlameSheet™ with PSM’s Gas Turbine Optimization Package (GTOP) to provide higher output through a combination of lower combustor pressure drop, higher mass flows and an increase in firing temperature, while maintaining sub-9ppm NOx emissions across the expanded operating range. Results are also presented for a second site on a unit that operates with up to 5% hydrogen blend into the baseline natural gas, where a reduction in NOx to sub-4 ppm levels at a typical 7F.03 baseload point has been safely and reliably achieved. Both results continue to demonstrate that fuel flexibility and expanded operational windows are possible to “future proof” existing gas turbine installations at a fraction of the cost of a new unit installation.

scholarly journals Utility Applications for Advanced Gas Turbines to Eliminate Thermal Pollution

1970 ◽  
Author(s):  
F. R. Biancardi ◽  
G. T. Peters
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Power Plants ◽  
Thermal Pollution ◽  
Power Demand ◽  
Water Requirements ◽  
Power Generation Systems ◽  
Alternative Solutions ◽  
Cost Characteristics

Increases in electric power demand during the next 30 years will sharply increase water requirements for condenser cooling and will stimulate the search for alternative solutions to the thermal pollution of our waters. Continuing engineering advances, achieved during extensive research and development efforts on military and commercial gas-turbine applications, could provide the basis for substantially improved power plants that could significantly alleviate thermal pollution. The authors describe the results of analytical studies to estimate the design technology, performance, and cost characteristics of future fossil- and nuclear-fueled gas-turbine power generation systems and the potential for eliminating thermal pollution.

Progress in Using Liquid Bio-Fuels in DLE Industrial Gas Turbines

2021 ◽  
Author(s):  
Priyank Saxena ◽  
William C. Steele ◽  
Luke H. Cowell
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbines ◽  
Tax Credits ◽  
Distributed Power ◽  
Biodiesel Blends ◽  
Distributed Power Generation ◽  
Fuel Flexibility ◽  
Industrial Gas Turbines ◽  
And Performance

Abstract Decarbonization of electricity is paramount for the success of curbing growth of greenhouse gas emissions in the atmosphere. For many power generation applications there is a growing interest in using bio-fuels to replace fossils-based fuels, such as diesel and natural gas. Bio-fuels, being plant-based fuels, are classified as carbon neutral fuels. Several distributed power generation sites, such as universities, are interested in the feasibility of burning bio-fuels, such as biodiesel and alcohols, in stationary gas turbines to reduce their carbon-footprint as well as earn tax credits. In order to maintain its leadership in fuel-flexibility and to support its distributed power generation customers, Solar has qualified several of its gas turbine models using both the conventional and dry low emissions (DLE) combustion systems on various biodiesel blends. This paper presents results of the combustion rig tests with DLE combustion injectors using biodiesel blends and their comparison with those of No. 2 diesel and natural gas fuels. The emissions (NOx, CO, UHC) from B20 biodiesel blend were similar to that of ULSD, but higher than natural gas. The results are summarized in terms of gas turbines emissions and performance. Impacts of fuel properties on storage, handling and gas turbines operations are discussed. Finally, future development opportunities are also presented.

Alternative Fuel Considerations for Gas Turbine Combustion

2007 ◽  
Author(s):  
Peter J. Stuttaford
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Carbon Dioxide Emissions ◽  
Gas Turbines ◽  
Power Plants ◽  
Practical Implementation ◽  
Combustion Dynamics ◽  
Gaseous Fuels ◽  
Wide Range ◽  
Critical Combustion

Gas turbines have the advantage of being able to operate on a wide range of fuels. Given the escalating cost of conventional fuel sources such as natural gas, there is increasing interest in, and implementation of, systems burning lower cost fuel gases. There are significant combustor performance effects when utilizing different fuels. Flame stability, emissions, durability, and combustion dynamics are critical combustion parameters which must be controlled when varying fuel constituents. Significant emphasis continues to be placed on the use of liquefied natural gas (LNG) as well as syngas derived from coal and petroleum coke. The elimination of carbon from gaseous coal based fuels also offers the possibility of burning hydrogen to reduce or eliminate carbon dioxide emissions. Existing stringent emissions permits must be met by power plants utilizing these different fuels. There is also a requirement for the flexible use of these fuels allowing power plants to switch real time between fuel sources using the same combustion hardware, without affecting commercial generating schedules. This highlights the requirement for fuel preparation and control skids, as well as robust combustion systems, for reliable plant operations. The objective of this work is to review fuel properties which affect combustion and consider the methods and tools used to characterize the subsequent combustion characteristics. The work focuses on gaseous fuel premixed combustion. A full scale high pressure combustion test stand was used to evaluate the effects of various gaseous fuels on given gas turbine combustor configurations. Data collected through the testing of natural gas containing heavy hydrocarbons, as might be expected from liquefied LNG or refinery offgas, and hydrogen based syngas fuel blends with natural gas to simulate various coal gas blends, is presented with conclusions drawn based upon the critical combustion parameters mentioned above. A methodology for fuel characterization and combustor qualification for the acceptable operation of gas turbine combustors on various gaseous fuels is discussed. The practical implementation of multi-fuel systems on commercially operating engines is also discussed, with emphasis on diluent free premixed systems.

Predicting Flameholding for Hydrogen and Natural Gas Flames at Gas Turbine Premixer Conditions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Elliot Sullivan-Lewis ◽  
Vincent McDonell
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Experimental Studies ◽  
Temperature Variations ◽  
Auto Ignition ◽  
Chamber Temperature ◽  
Transient Events ◽  
Significant Effort

Lean-premixed gas turbines are now common devices for low emissions stationary power generation. By creating a homogeneous mixture of fuel and air upstream of the combustion chamber, temperature variations are reduced within the combustor, which reduces emissions of nitrogen oxides. However, by premixing fuel and air, a potentially flammable mixture is established in a part of the engine not designed to contain a flame. If the flame propagates upstream from the combustor (flashback), significant engine damage can result. While significant effort has been put into developing flashback resistant combustors, these combustors are only capable of preventing flashback during steady operation of the engine. Transient events (e.g., auto-ignition within the premixer and pressure spikes during ignition) can trigger flashback that cannot be prevented with even the best combustor design. In these cases, preventing engine damage requires designing premixers that will not allow a flame to be sustained. Experimental studies were conducted to determine under what conditions premixed flames of hydrogen and natural gas can be anchored in a simulated gas turbine premixer. Tests have been conducted at pressures up to 9 atm, temperatures up to 750 K, and freestream velocities between 20 and 100 m/s. Flames were anchored in the wakes of features typical of premixer passageways, including cylinders, steps, and airfoils. The results of this study have been used to develop an engineering tool that predicts under what conditions a flame will anchor, and can be used for development of flame anchoring resistant gas turbine premixers.

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