A High-Temperature Catalytic Combustor With Starting Burner

2000 ◽  
Vol 123 (3) ◽  
pp. 543-549 ◽  
Author(s):  
Y. Yoshida ◽  
K. Oyakawa ◽  
Y. Aizawa ◽  
H. Kaya
Keyword(s):  
Steady State ◽  
Catalytic Combustion ◽  
Cold Start ◽  
Heating System ◽  
Operating Conditions ◽  
Combustion System ◽  
Cold Starting ◽  
Steady State Operation ◽  
Wide Range ◽  
Catalytic Combustor

A catalytic combustion system has high potential to achieve low NOx emission level. When this combustion system is applied to a gas turbine, the required combustor performance must be maintained over a wide range of operating conditions. These conditions range from cold starting to steady-state operation. Particularly during the initial stage of cold starting when the catalyst is not yet activated, the catalyst must be heated by some means. This study proposes a new concept of a catalytic combustor with a direct heating system using vaporizing tube for starting burner in order to downsize the combustor and reduce the warm-up time during cold starts. The effectiveness of this concept is experimentally verified. Furthermore, NOx, CO, and HC emissions during startup can be reduced to a low level so as to achieve ultra-low pollution of the catalytic combustion over a wide range of operating conditions from cold start to steady-state operation. This paper outlines the operation concept covering cold start, verification of the concept through the experiments with flame visualization in the combustor, spray characteristics, construction of the combustor, and combustion characteristics that show low pollution in various operating conditions of the catalytic combustor.

A High-Temperature Catalytic Combustor With Starting Burner

2000 ◽  
Author(s):  
Yusaku Yoshida ◽  
Kenshun Oyakawa ◽  
Yukio Aizawa ◽  
Hiroshi Kaya
Keyword(s):  
Steady State ◽  
Catalytic Combustion ◽  
Cold Start ◽  
Heating System ◽  
Operating Conditions ◽  
Combustion System ◽  
Cold Starting ◽  
Steady State Operation ◽  
Wide Range ◽  
Catalytic Combustor

A catalytic combustion system has high potential to achieve low NOx emission level. When this combustion system is applied to a gas turbine, the required combustor performance must be maintained over a wide range of operating conditions. These conditions range from cold starting to steady-state operation. Particularly during the initial stage of cold starting when the catalyst is not yet activated, the catalyst must be heated by some means. This study proposes a new concept of a catalytic combustor with a direct heating system using vaporizing tube for starting burner in order to downsize the combustor and reduce the warm-up time during cold starts. The effectiveness of this concept is experimentally verified. Furthermore, NOx, CO, and HC emissions during startup can be reduced to a low level so as to achieve ultra-low pollution of the catalytic combustion over a wide range of operating conditions from cold start to steady-state operation. This paper outlines the operation concept covering cold start, verification of the concept through the experiments with flame visualization in the combustor, spray characteristics, construction of the combustor, and combustion characteristics that show low pollution in various operating conditions of the catalytic combustor.

Measured Torsional Vibration Characteristics of a 100 Megawatt Wind Tunnel Drive Line

1999 ◽  
Author(s):  
James M. Corliss ◽  
H. Sprysl
Keyword(s):  
Steady State ◽  
Damping Ratio ◽  
Forced Response ◽  
Operating Conditions ◽  
Pulse Load ◽  
Torsional Vibrations ◽  
Variable Frequency Drive ◽  
Steady State Operation ◽  
Torque Measurements ◽  
Torsional Analysis

Abstract A new 100 MW (135,000 Hp) adjustable speed drive system has recently been installed in the NASA Langley National Transonic Facility. The 100 MW system is the largest of its kind in the world and consists of a salient pole synchronous motor powered by a 12-pulse Load Commutated Inverter variable frequency drive. During system commissioning the drive line torsional vibrations were measured with strain gages and a telemetry-based data acquisition system. The torque measurements included drive start-up and steady-state operation at speeds where the drive motor’s pulsating torques match the drive line’s torsional natural frequency. Rapid drive acceleration rates with short dwell times were effective in reducing torsional vibrations during drive starts. Measured peak torsional vibrations during steady-state operation were comparable to predicted values and large enough to produce noticeable lateral vibrations in the drive line shafting. Cyclic shaft stresses for all operating conditions were well within the fatigue limits of the drive line components. A comparison of the torque measurements to an analytical forced response model concluded that a 0.5% critical damping ratio was appropriately applied in the drive line’s torsional analysis.

Modeling Heat and Mass Transfer Correlations for Flow Through Micro Channels in Monolith Honeycomb Catalytic Combustor

2009 ◽  
Author(s):  
Juan Yin ◽  
Yi-wu Weng
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Catalytic Combustion ◽  
Operating Conditions ◽  
Performance Characteristics ◽  
Predicting Performance ◽  
Micro Channels ◽  
Characteristics Analysis ◽  
Flow Through ◽  
Catalytic Combustor

This paper investigated performance characteristics analysis of catalytic combustion by utilizing 1-D models incorporated heat and mass transfer correlations. The 1-D numerical results were compared with 2-D models studies and experimental data. The performance characteristics were mainly the effects of operating conditions on methane conversion rate. The comparable analysis confirmed that 1-D model can success in predicting performance of catalytic combustion when empiric inter-phase heat and mass transfer correlations are used and appropriate operating conditions are chosen.

Asymptotic Analysis of a Narrow Gas-Lubricated, Flat Sector Thrust Bearing

1988 ◽  
Vol 110 (3) ◽  
pp. 427-433 ◽  
Author(s):  
J. J. Shepherd
Keyword(s):  
Steady State ◽  
Numerical Methods ◽  
Power Loss ◽  
Thrust Bearing ◽  
Center Of Pressure ◽  
Operating Conditions ◽  
Load Bearing Capacity ◽  
Steady State Operation ◽  
Bearing Number ◽  
Continuous Range

The method of matched expansions is employed to analyze the steady state operation of a finite gas-lubricated flat sector bearing for the case where the ratio of radial to circumferential dimensions is small and the relevant bearing number, Λ, is moderate. This technique yields general expressions for the pressure distribution, load bearing capacity, power loss and center of pressure location that are valid for a significant and continuous range of bearing dimensions, orientations and operating conditions. Comparisons are made, where possible, with the existing results from the literature obtained by numerical methods.

Performance evaluation of SBR treatment for nitrogen removal from tannery wastewater

2006 ◽  
Vol 53 (12) ◽  
pp. 275-284 ◽  
Author(s):  
S. Murat ◽  
G. Insel ◽  
N. Artan ◽  
D. Orhon
Keyword(s):  
Steady State ◽  
Nitrogen Removal ◽  
System Performance ◽  
Model Simulation ◽  
Pilot Scale ◽  
Simulation System ◽  
Nitrogen Compounds ◽  
Concentration Profiles ◽  
Steady State Operation ◽  
Wide Range

Performance of SBR treatment for nitrogen removal from tannery is evaluated for a wide range of wastewater temperature between 7 and 30 °C. A pilot-scale SBR unit fed with plain-settled wastewater is operated on site for this purpose. Effective nitrogen removal is sustained by adjustment of the sludge age from 28 to 5 days. Concentration profiles of nitrogen compounds within a selected complete SBR cycle during the steady state operation at different wastewater temperatures and sludge ages are evaluated by model simulation. System performance is also interpreted in terms of modeling and stoichiometric calculation. Additional nitrate loss was observed during aerobic period when the aeration intensity was reduced by the factor of 50%.

Exploration of Compact Combustors for Reheat Cycle Aero Engine Applications

2006 ◽  
Author(s):  
J. Zelina ◽  
D. T. Shouse ◽  
J. S. Stutrud ◽  
G. J. Sturgess ◽  
W. M. Roquemore
Keyword(s):  
Gas Turbine ◽  
Temperature Rise ◽  
Gas Turbines ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Combustion System ◽  
Turbine Engine ◽  
Lean Blowout ◽  
Power Extraction ◽  
Wide Range

An aero gas turbine engine has been proposed that uses a near-constant-temperature (NCT) cycle and an Inter-Turbine Burner (ITB) to provide large amounts of power extraction from the low-pressure turbine. This level of energy is achieved with a modest temperature rise across the ITB. The additional energy can be used to power a large geared fan for an ultra-high bypass ratio transport aircraft, or to drive an alternator for large amounts of electrical power extraction. Conventional gas turbines engines cannot drive ultra-large diameter fans without causing excessively high turbine temperatures, and cannot meet high power extraction demands without a loss of engine thrust. Reducing the size of the combustion system is key to make use of a NCT gas turbine cycle. Ultra-compact combustor (UCC) concepts are being explored experimentally. These systems use high swirl in a circumferential cavity about the engine centerline to enhance reaction rates via high cavity g-loading on the order of 3000 g’s. Any increase in reaction rate can be exploited to reduce combustor volume. The UCC design integrates compressor and turbine features which will enable a shorter and potentially less complex gas turbine engine. This paper will present experimental data of the Ultra-Compact Combustor (UCC) performance in vitiated flow. Vitiation levels were varied from 12–20% oxygen levels to simulate exhaust from the high pressure turbine (HPT). Experimental results from the ITB at atmospheric pressure indicate that the combustion system operates at 97–99% combustion efficiency over a wide range of operating conditions burning JP-8 +100 fuel. Flame lengths were extremely short, at about 50% of those seen in conventional systems. A wide range of operation is possible with lean blowout fuel-air ratio limits at 25–50% below the value of current systems. These results are significant because the ITB only requires a small (300°F) temperature rise for optimal power extraction, leading to operation of the ITB at near-lean-blowout limits of conventional combustor designs. This data lays the foundation for the design space required for future engine designs.

scholarly journals Development of a Catalytic Combustor for a Heavy-Duty Utility Gas Turbine

1996 ◽  
Author(s):  
Ralph A. Dalla Betta ◽  
James C. Schlatter ◽  
Sarento G. Nickolas ◽  
Martin B. Cutrone ◽  
Kenneth W. Beebe ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Catalytic Combustion ◽  
Full Scale ◽  
Inlet Temperature ◽  
Nox Emissions ◽  
Combustion System ◽  
Catalytic Reactor ◽  
Heavy Duty ◽  
Catalytic Combustor

The most effective technologies currently available for controlling NOx emissions from heavy-duty industrial gas turbines are either diluent injection in the combustor reaction zone, or lean premixed Dry Low NOx (DLN) combustion. For ultra low emissions requirements, these must be combined with selective catalytic reduction (SCR) DeNOx systems in the gas turbine exhaust. An alternative technology for achieving comparable emissions levels with the potential for lower capital investment and operating cost is catalytic combustion of lean premixed fuel and air within the gas turbine. The design of a catalytic combustion system using natural gas fuel has been prepared for the GE model MS9OOIE gas turbine. This machine has a turbine inlet temperature to the first rotating stage of over 1100°C and produces approximately 105 MW electrical output in simple cycle operation. The 508 mm diameter catalytic combustor designed for this gas turbine was operated at full-scale conditions in tests conducted in 1992 and 1994. The combustor was operated for twelve hours during the 1994 test and demonstrated very low NOx emissions from the catalytic reactor. The total exhaust NOx level was approximately 12–15 ppmv and was produced almost entirely in the preburner ahead of the reactor. A small quantity of steam injected into the preburner reduced the NOx emissions to 5–6 ppmv. Development of the combustion system has continued with the objectives of reducing CO and UHC emissions, understanding the parameters affecting reactor stability and spatial non-uniformities which were observed at low inlet temperature, and improving the structural integrity of the reactor system to a level required for commercial operation of gas turbines. Design modifications were completed and combustion hardware was fabricated for additional full-scale tests of the catalytic combustion system in March 1995 and January 1996. This paper presents a discussion of the combustor design, the catalytic reactor design and the results of full-scale testing of the improved combustor at MS9OOIE cycle conditions in the March 1995 and January 1996 tests. Major improvements in performance were achieved with CO and UHC emissions of 10 ppmv and 0 ppmv at base load conditions. This ongoing program will lead to two additional full-scale combustion system tests in 1996. The results of these tests will be available for discussion at the June 1996 Conference in Birmingham.

Simulation of an Industrial Linear Low Density Polyethylene Plant

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Ali Farhangiyan Kashani ◽  
Hossein Abedini ◽  
Mohammad Reza Kalaee
Keyword(s):  
Steady State ◽  
Average Molecular Weight ◽  
Molar Fraction ◽  
Operating Conditions ◽  
Low Density Polyethylene ◽  
Process Equipment ◽  
Flow Index ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Wide Range

In this paper, an industrial linear low density polyethylene (LLDPE) production process including two serried fluidized bed reactors (FBR) and other process equipment was completely simulated in steady state mode. Both of FBRs were considered like two serried continuous stirred tank reactors (CSTR). In this simulation, a kinetic model that is based on a multiple active site heterogeneous Ziegler-Natta catalyst was used for simulation of reactions in two FBRs. Simulator by using this model is able to predict the important attributes of LLDPE like melt flow index (MFI), density (ρ), polydispersity (PDI), numerical and weight average molecular weight (Mn, Mw) and co-polymer molar fraction (SFRAC). On the other hand, this simulator can be applied in wide range of changing in inlet operating conditions. The results of the simulation are compared with industrial data of LLDPE plant. A good agreement is observed between the simulator predictions and actual plant data. Finally, by using of the simulator, the steady state operating conditions for producing different grades of polyethylene are obtained.

VPO Transient Oxidation Kinetics

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Gregory S. Patience ◽  
Maria-Jesus Lorences
Keyword(s):  
Steady State ◽  
Maleic Anhydride ◽  
Oxidation Rate ◽  
Circulating Fluidized Bed ◽  
Operating Conditions ◽  
Adsorption Sites ◽  
Carbon Adsorption ◽  
Reducing Conditions ◽  
Steady State Operation ◽  
Adsorbed Carbon

Transient and steady state reactor data for the partial oxidation of butane to maleic anhydride were collected in a fluid bed over DuPont commercial vanadium pyrophosphate catalyst (VPO) principally under butane rich, oxygen deficient operating conditions. Under moderate reducing conditions, oxygen becomes the determining factor for maleic anhydride productivity and selectivity. As the oxygen becomes depleted, minor changes in butane conversion impacts the selectivity substantially. However, when VPO catalyst is pre-exposed to oxygen for a substantial period of time (as practiced in Circulating Fluidized Bed technology), selectivity may be improved and maleic anhydride yields four times the steady state operation values are achieved. As the butane-to-oxygen ratio rises above 1, carbon deposits onto the surface of the catalyst, resulting in lower activity and selectivity. Based on a detailed reaction engineering model, the re-oxidation rate of the adsorbed carbon is 1st order with respect to the carbon adsorption sites and ½ order in oxygen. The re-oxidation rate of the reduced catalyst appears to be 1st order in sites and oxygen.

scholarly journals Concurrent operation of 10 gyrotrons at W7-X experience and improvement opportunities

2018 ◽  
Vol 187 ◽  
pp. 01003 ◽  
Author(s):  
H. Braune ◽  
K.J. Brunner ◽  
H.P. Laqua ◽  
S. Marsen ◽  
D. Moseev ◽  
...  
Keyword(s):  
Steady State ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Heating System ◽  
Current Drive ◽  
Electron Cyclotron Resonance Heating ◽  
Neutral Gas ◽  
Steady State Operation ◽  
Start Up ◽  
Operation Phase

At the stellarator Wendelstein 7-X (W7-X) Electron Cyclotron Resonance Heating (ECRH) is the main heating system for steady-state operation and was the only available heating system during the operation phase OP1.2a in 2017. The ECRH, equipped with 10 operational 140 GHz gyrotrons [1], was used for different tasks at W7-X such as wall conditioning, controlled plasma start-up from the neutral gas up to steady state plasma control and different heating scenarios such as X2-mode and O2-mode heating as well as current drive (ECCD). The operational experiences and improvement opportunities of the ECRH plant will be discussed.

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