Experimental Study on Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Mass Flow ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Combined Cycle ◽  
Range Extension ◽  
Nox Emissions ◽  
Low Load

Volatile renewable energy sources induce power supply fluctuations. These need to be compensated by flexible conventional power plants. Gas turbines in combined cycle power plants adjust the power output quickly but their turn-down ratio is limited by the slow reaction kinetics, which leads to CO and unburned hydrocarbon emissions. To extend the turn-down ratio, part of the fuel can be converted to syngas, which exhibits a higher reactivity. By an increasing fraction of syngas in the fuel, the reactivity of the mixture is increased and total fuel mass flow and the power output can be reduced. An autothermal on-board syngas generator in combination with two different burner concepts for natural gas (NG)/syngas mixtures was presented in a previous study (Baumgärtner, M. H., and Sattelmayer, T., 2017, “Low Load Operation Range Extension by Autothermal On-Board Syngas Generation,” ASME J. Eng. Gas Turbines Power, 140(4), p. 041505). The study at hand shows a mass-flow variation of the reforming process with mass flows, which allow for pure syngas combustion and further improvements of the two burner concepts which result in a more application-oriented operation. The first of the two burner concepts comprises a generic swirl stage with a central lance for syngas injection. Syngas is injected with swirl to avoid a negative impact on the total swirl intensity and nonswirled. The second concept includes a central swirl stage with an outer ring of jets. For this burner, syngas is injected in both stages to avoid NOx emissions from the swirl stage. Increased NOx emissions produced by NG combustion of the swirl pilot were reported in last year's paper. For both burners, combustion performance is analyzed by OH*-chemiluminescence and gaseous emissions. The lowest possible adiabatic flame temperature without a significant increase of CO emissions was 170–210 K lower for the syngas compared to low load pure NG combustion. This corresponds to a decrease of 15–20% in terms of thermal power.

Experimental Study on Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2018 ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Mass Flow ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Gas Combustion ◽  
Low Load ◽  
Natural Gas Combustion

Volatile renewable energy sources induce power supply fluctuations. These need to be compensated by flexible conventional power plants. Gas turbines in combined cycle power plants adjust the power output quickly but their turn-down ratio is limited by the slow reaction kinetics which lead to CO and unburned hydrocarbon (UHC) emissions. To extend the turn-down ratio, part of the fuel can be converted to syngas, which exhibits a higher reactivity. By an increasing fraction of syngas in the fuel, the reactivity of the mixture is increased and total fuel mass-flow and the power output can be reduced. An Autothermal On-board Syngas Generator in combination with two different burner concepts for natural gas/syngas mixtures was presented in a previous study [1]. The study at hand shows a mass-flow variation of the reforming process with mass-flows which allow for pure syngas combustion and further improvements of the two burner concepts which result in a more application-oriented operation. The first of the two burner concepts comprises a generic swirl stage with a central lance for syngas injection. Syngas is injected with swirl to avoid a negative impact on the total swirl intensity and non-swirled. The second concept includes a central swirl stage with an outer ring of jets. For this burner, syngas is injected in both stages to avoid NOx emissions from the swirl stage. Increased NOx emissions produced by natural gas combustion of the swirl pilot was reported in last year’s paper. For both burners, combustion performance is analyzed by OH*-chemiluminescence and gaseous emissions. The lowest possible adiabatic flame temperature without a significant increase of CO emissions was 170 K – 210 K lower for the syngas compared to low load pure natural gas combustion. This corresponds to a decrease of 15–20 % in terms of thermal power.

Improvement of Selective Catalytic Reduction System Performance in Combined Cycle Power Plants

2003 ◽  
Author(s):  
Anatoly Sobolevskiy ◽  
Tom Czapleski ◽  
Richard Murray
Keyword(s):  
Selective Catalytic Reduction ◽  
Mass Flow ◽  
System Performance ◽  
Gas Turbines ◽  
Power Plants ◽  
Catalytic Reduction ◽  
Active Material ◽  
Combined Cycle ◽  
Nox Emissions ◽  
Scr System

Environmental regulations are very stringent in the U.S., requiring very low emissions of nitrogen oxides (NOx) from combined cycle power plants. Selective Catalytic Reduction (SCR) systems utilizing vanadium pentoxide (V2O5) as the active material in the catalyst are a proven method of reducing NOx emissions in the exhaust stack of gas turbines with heat recovery steam generators (HRSG) to 2–4 ppmvd. These low NOx emissions levels require an increase of SCR removal efficiency to the level of 90+ % with limited ammonia slip. The distribution of flow velocities, temperature, and NOx mass flow at the inlet of the SCR are critical to minimizing NOx and ammonia (NH3) concentrations in HRSG stack. The short distance between the ammonia injection grid and the catalyst in the HRSG complicates the achievement of homogeneous NH3 and NOx mixture. To better understand the influence of the above factors on overall SCR system performance, field testing of combined cycle power plants with an SCR installed in the HRSG has been conducted. Uniformity of exhaust flow, temperature and NOx emissions upstream and downstream of the SCR were examined and the results served as a basis for SCR system tuning in order to increase its efficiency. NOx mass flow profiles upstream and downstream of the SCR were used to assess ammonia distribution enhancement. Ammonia flow adjustments within a cross section of the exhaust gas duct yielded significantly improved NOx mass flow uniformity after the SCR while reducing ammonia consumption. Based on field experience, a procedure for ammonia distribution grid tuning was developed and recommendations for SCR performance improvement were generated.

A New Concept for Power Grid Stabilization Using a Motor-Assisted Variable Speed Gas Turbine System

2014 ◽  
Author(s):  
Naohiro Kusumi ◽  
Noriaki Hino ◽  
Aung Ko Thet
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Power Grid ◽  
Renewable Energy Sources ◽  
Thermal Power ◽  
Rotational Energy ◽  
Thermal Power Plants ◽  
Variable Speed

As the penetration ratio of renewable energy sources becomes larger, the fluctuations of grid load also become larger and larger because of the intermittent generation of wind power and photovoltaic power. These fluctuations cause instability of voltage and frequency in the power grid. Recently, there has been considerable research into solving these challenges, leading to development such as batteries, flywheels, and improved flexibility of thermal power plants. The batteries and the flywheels are confronted with the challenge of high initial cost for the Mega-Watt class. Improving flexibility for the thermal power plants is effective, but this improvement has several limitations such as load-follow operation capability under mechanical constraints and frequency regulation within governor-free regulating capacity. To overcome these problems, we propose a new gas turbine system named Motor-assisted Gas Turbine (MAGT). MAGT is composed of a two-shaft gas turbine: one free turbine shaft is connected to a synchronous generator rotating at a constant speed, and the other compressor shaft is coupled to an inverter-fed motor controlled at variable speed. The motor and inverter capacity is appropriate: about 5–10 % that of the gas turbine. MAGT improved the reaction rate corresponding to the load fluctuation by changing the speed of the compressor. Since the motor’s shaft, which has a compressor and a high pressure turbine, rotates at high speed and those masses are considerable, it has rotational energy of about several kWh. This energy could be charged and discharged through the converter that controls the motor speed, the same as for flywheels. This response could be much faster than conventional gas turbines, which contain huge amounts of working gas. MAGT controls its rotational energy in seconds and controls gas turbine power in minutes; thereby it improves response totally. Moreover, by assisting the compressor by using motor power, MAGT can increase gas turbine power output. Since the density of air decreases with as temperature increase, the mass of working gas is reduced. Thus, the fuel input must accordingly be reduced to suppress the combustion temperature without damaging turbine blades. As a result, power output is reduced. In such cases, a motor-assisted compressor can increase working gas. That allows more fuel input. The proposed system was evaluated using numerical simulations. The results showed that frequency variations were within ±0.1Hz and the output power was recovered under high ambient temperature.

Low Load Operation Range Extension by Autothermal On-Board Syngas Generation

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
Renewable Energy Sources ◽  
Flame Temperature ◽  
Combined Cycle ◽  
Sudden Increase ◽  
Gaseous Emissions ◽  
Fuel Processor ◽  
Burn Out ◽  
Unburned Hydrocarbons

The increasing amount of volatile renewable energy sources drives the necessity of flexible conventional power plants to compensate for fluctuations of the power supply. Gas turbines in a combined cycle power plant (CCPP) adjust the power output quickly but a sudden increase of CO and unburned hydrocarbons emissions limits their turn-down ratio. To extend the turn-down ratio, part of the fuel can be processed to syngas, which exerts a higher reactivity. An autothermal on-board syngas generator in combination with two different burner concepts for natural gas (NG) and syngas mixtures is presented in this study. A mixture of NG, water vapor, and air reacts catalytically in an autothermal reactor test rig to form syngas. At atmospheric pressure, the fuel processor generates syngas with a hydrogen content of −30 vol % and a temperature of 800 K within a residence time of 200 ms. One concept for the combustion of NG and syngas mixtures comprises a generic swirl stage with a central lance injector for the syngas. The second concept includes a central swirl stage with an outer ring of jets. The combustion is analyzed for both concepts by OH*-chemiluminescence, lean blow out (LBO) limit, and gaseous emissions. The central lance concept with syngas injection exhibits an LBO adiabatic flame temperature that is 150 K lower than in premixed NG operation. For the second concept, an extension of almost 200 K with low CO emission levels can be reached. This study shows that autothermal on-board syngas generation is feasible and efficient in terms of turn-down ratio extension and CO burn-out.

scholarly journals Boosting Steam Plant Thermal Efficiency and Power Output Through the Addition of Gas Turbines

1987 ◽  
Author(s):  
M. J. J. Linnemeijer ◽  
J. P. van Buijtenen ◽  
A. U. van Loon
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
Combined Cycle ◽  
Steam Power ◽  
Power Stations ◽  
Steam Power Plants ◽  
General Terms ◽  
Utility Companies ◽  
Steam Plant

This paper describes the conversion of existing conventional steam power plants into combined cycle plants. A number of Dutch utility companies are currently performing or planning this conversion on their gas-fired power stations, mainly in order to conserve fuel. Modifications of boiler and steam cycle, necessary for the new concept, are presented in general terms, together with a detailed description of one of the projects.

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 Installations for EDF’s Island Grids

1991 ◽  
Author(s):  
C. Cazemajou ◽  
C. Morzelle
Keyword(s):  
Gas Turbines ◽  
Power Plants ◽  
French Guiana ◽  
Thermal Power ◽  
Combined Cycle ◽  
Production And Distribution ◽  
The Indian Ocean ◽  
Technical Details ◽  
The Caribbean ◽  
Development Prospects

EDF is responsible for the production and distribution of electricity on the French islands in Europe and overseas, such as: - Corsica (in the Mediterranean), - Martinique (in the Caribbean), - Guadeloupe (in the Caribbean), - Reunion (in the Indian Ocean), - and French Guiana in South America. Technical and economic studies revealed the viability in these regions of single cycle gas turbine technology for supplying peak demand requirements, or providing transitory means of production pending the installation of heavier production units (conventional thermal power plants, diesel generators or hydropower). After consultations with the major European manufacturers, a list of machines with the capacity to meet the generation specifications, and their characteristics, was prepared. On mainland France EDF had equipped its production units with 24 MW Alsthom MS 5000 and MS 5001 gas turbines. These were little used and studies showed the economic viability of transferring these units to island regions. The program finally adopted was to install the following power generation facilities: JARRY SUD (GUADELOUPE): 2 ALSTHOM MS 5001 – 20 MW – 40 MW KOUROU (FRENCH GUIANA): 2 COOPER ROLLS – 13 MW – 26 MW; 1 ROLLS ROYCE – 11 MW – 11 MW LUCCIANA (CORSICA): 2 ALSTHOM MS 5000 – 24 MW – 48 MW LE PORT (REUNION): 2 ALSTHOM MS 5001 – 20 MW – 40 MW POINTE DES CARRIERES (MARTINIQUE): 2 ALSTHOM MS 5001 – 20 MW – 40 MW or total rated power of: 205 MW The technical details, costs and scheduling of these works are described in the paper. Finally, the authors describe the future development prospects for gas turbines in these regions, and especially certain combined cycle projects for Corsica coupled with a proposed Italy-Corsica-Sardinia natural gas link.

Options to Maximize Power Output for Merchant Plants in Combined Cycle Applications

2001 ◽  
Author(s):  
Rattan Tawney ◽  
Cheryl Pearson ◽  
Mona Brown
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Life Cycle Cost ◽  
Peak Power ◽  
Power Plants ◽  
High Reliability ◽  
Combined Cycle ◽  
Cycle Performance ◽  
Plant Design ◽  
Capital Costs

Deregulation and growth in the power industry are causing dramatic changes in power production and distribution. The demand for peak power and potentially high revenues due to premium electricity rates has attracted independent developers to the concept of Merchant Power Plants (MPPs). Over 100,000 MW of greenfield capacity is currently being developed through approximately 200 merchant plants in North America. These MPPs will have no captive customers or long-term power purchase agreements, but will rely on selling electricity into a volatile electricity spot market. Because of this, MPPs need the capability to export as much power as possible on demand. MPPs must also have the capability to produce significant assets in order to compete in the marketplace, based on both technical and commercial operation factors such as value engineering, life-cycle cost management, and information technology. It is no surprise then, that almost all merchant project developers have specified combined cycle (CC) technology. The CC power plant offers the highest thermal efficiency of all electric generating systems commercially available today. It also exhibits low capital costs, low emissions, fuel and operating flexibility, low operation and maintenance costs, short installation schedule, and high reliability/availability. However, since gas turbines (GTs) are the basis for CC power plants, these plants experience power output reductions in the range of 10 to 15 percent during summer months, the period most associated with peak power demand. In order to regain this loss of output as well as to provide additional power to meet peak demands, the most common options are GT inlet fogging, GT steam injection, and heat recovery steam generator (HRSG) supplemental firing. This paper focuses on plant design, cycle performance, and the economics of plant configuration associated with these options. Guidelines are presented in this paper to assist the owner in selecting power enhancement options for the MPP that will maximize their Return on Equity (ROE).

Genetic Optimization of Steam Injected Gas Turbine Power Plants

2002 ◽  
Author(s):  
Ibrahim Sinan Akmandor ◽  
O¨zhan O¨ksu¨z ◽  
Sec¸kin Go¨kaltun ◽  
Melih Han Bilgin
Keyword(s):  
Gas Turbine ◽  
Power Output ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Power Plants ◽  
Pressure Ratio ◽  
Steam Injection ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Compressor Pressure Ratio

A new methodology is developed to find the optimal steam injection levels in simple and combined cycle gas turbine power plants. When steam injection process is being applied to simple cycle gas turbines, it is shown to offer many benefits, including increased power output and efficiency as well as reduced exhaust emissions. For combined cycle power plants, steam injection in the gas turbine, significantly decreases the amount of flow and energy through the steam turbine and the overall power output of the combined cycle is decreased. This study focuses on finding the maximum power output and efficiency of steam injected simple and combined cycle gas turbines. For that purpose, the thermodynamic cycle analysis and a genetic algorithm are linked within an automated design loop. The multi-parameter objective function is either based on the power output or on the overall thermal efficiency. NOx levels have also been taken into account in a third objective function denoted as steam injection effectiveness. The calculations are done for a wide range of parameters such as compressor pressure ratio, turbine inlet temperature, air and steam mass flow rates. Firstly, 6 widely used simple and combined cycle power plants performance are used as test cases for thermodynamic cycle validation. Secondly, gas turbine main parameters are modified to yield the maximum generator power and thermal efficiency. Finally, the effects of uniform crossover, creep mutation, different random number seeds, population size and the number of children per pair of parents on the performance of the genetic algorithm are studied. Parametric analyses show that application of high turbine inlet temperature, high air mass flow rate and no steam injection lead to high power and high combined cycle thermal efficiency. On the contrary, when NOx reduction is desired, steam injection is necessary. For simple cycle, almost full amount of steam injection is required to increase power and efficiency as well as to reduce NOx. Moreover, it is found that the compressor pressure ratio for high power output is significantly lower than the compressor pressure ratio that drives the high thermal efficiency.

Combined-Cycle Power Plants From Gas Turbines and Geothermal Source Integration

1993 ◽  
Author(s):  
R. Bettocchi ◽  
G. Cantore ◽  
G. Negri di Montenegro ◽  
A. Peretto ◽  
E. Gadda
Keyword(s):  
Power Output ◽  
Gas Turbines ◽  
Power Plants ◽  
High Efficiency ◽  
Combined Cycle ◽  
Point Of View ◽  
Total Power ◽  
Geothermal Fluid ◽  
Exhaust Gases ◽  
Plant Power

Geothermal power plants have difficulties due to the low conversion efficiencies achievable. Geothermal integrated combined cycle proposed and analyzed in this paper is a way to achieve high efficiency. In the proposed cycle the geothermal fluid energy is added, through suitable heat ecxhangers, to that of exhaust gases for generating a steam cycle. The proposed cycle maintains the geothermal fluid segregated from ambient and this can be positive on the environmental point of view. Many systems configurations, based on this possibility, can be taken into account to get the best thermodynamic result. The perfomed analysis examines different possible sharings between the heat coming from geothermal and exhaust gases, and gives the resulting system efficiencies. Various pressures of the geothermal steam and water dominated sources are also taken into account. As a result the analysis shows that the integrated plant power output is largely greater than the total power obtained by summing the gas turbine and the traditional geothermal plant power output, considered separately.

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