Time-Dependent Deposition Characteristics of Fine Coal Fly Ash in a Laboratory Gas Turbine Environment

2012 ◽  
Vol 135 (2) ◽  
Author(s):  
Robert G. Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Fly Ash ◽  
Surface Temperature ◽  
Gas Turbine ◽  
Gas Flow ◽  
Coal Fly Ash ◽  
Time Dependent ◽  
Gas Temperature ◽  
Brigham Young University ◽  
Fine Coal ◽  
Two Samples

Time-dependent deposition characteristics of fine coal fly ash were measured in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Two samples of subbituminous coal fly ash, with mass mean diameters of 3 μm and 13 μm, were entrained in a hot gas flow with a gas temperature of 1288 °C and Mach number of 0.25. A nickel-based, superalloy metal coupon approximately 0.3 cm thick was held in a hot particle-laden gas stream to simulate deposition in a gas turbine. Tests were conducted with deposition times of 20, 40, and 60 min. Capture efficiencies and surface roughness characteristics (e.g., Ra) were obtained at different times. Capture efficiency increased exponentially with time, while Ra increased linearly with time. The increased deposition with time caused the surface temperature of the deposit to increase. The increased surface temperature caused more softening, increasing the propensity for impacting particles to stick to the surface. These data are important for improving models of deposition in turbines from syngas flows.

Time-Dependent Deposition Characteristics of Fine Coal Flyash in a Laboratory Gas Turbine Environment

2011 ◽  
Author(s):  
Robert G. Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Gas Flow ◽  
Coal Fly Ash ◽  
Time Dependent ◽  
Gas Temperature ◽  
Brigham Young University ◽  
Fine Coal ◽  
Two Samples ◽  
Nickel Base

Time-dependent deposition characteristics of fine coal flyash were measured in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Two samples of subbituminous coal fly ash, with mass mean diameters of 3 and 13 μm, were entrained in a hot gas flow with a gas temperature of 1250°C and Mach number of 0.25. A nickel base super alloy metal coupon approximately 0.3 cm thick was held in a hot particle-laden gas stream to simulate deposition in a gas turbine. Tests were conducted with deposition times of 20, 40, and 60 minutes. Capture efficiencies and surface roughness characteristics (e.g., Ra) were obtained at different times. Capture efficiency increased exponentially with time while Ra increased linearly with time. The increased deposition with time caused the surface temperature of the deposit to increase. The increased surface temperature caused more softening, increasing the propensity for impacting particles to stick to the surface. These data are important for improving models of deposition in turbines from syngas flows.

Independent Effects of Surface and Gas Temperature on Coal Fly Ash Deposition in Gas Turbines at Temperatures up to 1400 °C

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Robert Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Fly Ash ◽  
Surface Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Coal Fly Ash ◽  
Combined Cycle ◽  
Capture Efficiency ◽  
Gas Temperature ◽  
Independent Effects

Deposition of coal fly ash in gas turbines has been studied to support the concept of integrated gasification combined cycle (IGCC). Although particle filters are used in IGCC, small amounts of ash particles less than 5 μm in diameter enter the gas turbine. Previous deposition experiments in the literature have been conducted at temperatures up to about 1288 °C. However, few tests have been conducted that reveal the independent effects of gas and surface temperature, and most have been conducted at gas temperatures lower than 1400 °C. The independent effects of gas and surface temperature on particle deposition in a gas turbine environment were measured using the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Gas temperatures were measured with a type K thermocouple and surface temperatures were measured with two-color pyrometry. This facility was modified for testing at temperatures up to 1400 °C. Subbituminous coal fly ash, with a mass mean diameter of 4 μm, was entrained in a hot gas flow at a Mach number of 0.25. A nickel base super alloy metal coupon 2.5 cm in diameter was held in this gas stream to simulate deposition in a gas turbine. The gas temperature (and hence particle temperature) governs the softening and viscosity of the particle, while the surface temperature governs the stickiness of the deposit. Two test series were therefore conducted. The first series used backside cooling to hold the initial temperature of the deposition surface (Ts,i) constant at 1000 °C while varying the gas temperature (Tg) from 1250 °C to 1400 °C. The second series held Tg constant at 1400 °C while varying Ts,i from 1050 °C to 1200 °C by varying the amount of backside cooling. Capture efficiency and surface roughness were calculated. Capture efficiency increased with increasing Tg. Capture efficiency also initially increased with Ts,i until a certain threshold temperature where capture efficiency began to decrease with increasing Ts,i.

scholarly journals Observations of Flame Behavior From a Practical Fuel Injector Using Gaseous Fuel in a Technology Combustor

1994 ◽  
Author(s):  
Paul O. Hedman ◽  
Geoffrey J. Sturgess ◽  
David L. Warren ◽  
Larry P. Goss ◽  
Dale T. Shouse
Keyword(s):  
Gas Turbine ◽  
Air Force ◽  
Diffusion Flames ◽  
Fuel Injector ◽  
Gas Temperature ◽  
Brigham Young University ◽  
Lean Blowout ◽  
Reaction Zones ◽  
Air Force Base ◽  
Whitney Aircraft

This paper presents results from an Air Force program being conducted by researchers at Brigham Young University (BYU) Wright-Patterson Air Force Base (WPAFB), and Pratt and Whitney Aircraft Co (P&W). This study is part of a comprehensive effort being supported by the Aero Propulsion and Power Laboratory at Wright-Patterson Air Force Base, and Pratt and Whitney Aircraft, Inc. in which simple and complex diffusion flames are being studied to better understand the fundamentals of gas turbine combustion near lean blowout. The program’s long term goal is to improve the design methodology of gas turbine combustors. This paper focuses on four areas of investigation: 1) digitized images from still film photographs to document the observed flame structures as fuel equivalence ratio was varied, 2) sets of LDA data to quantify the velocity flow fields existing in the burner, 3) CARS measurements of gas temperature to determine the temperature field in the combustion zone, and to evaluate the magnitude of peak temperature, and 4) two-dimensional images of OH radical concentrations using PLIF to document the instantaneous location of the flame reaction zones.

Carbochlorination of Fly Ash in a Fused Salt Slurry Reactor

1986 ◽  
Vol 86 ◽  
Author(s):  
M. S. Dobbins ◽  
G. Burnet
Keyword(s):  
Mass Transfer ◽  
Fly Ash ◽  
Gas Flow ◽  
Mixed Oxides ◽  
Batch Reactor ◽  
Coal Fly Ash ◽  
Pure Alumina ◽  
Higher Temperature ◽  
Liquid Mass Transfer ◽  
Temperature Oxide

ABSTRACTCarbochlorination of the metal oxides in fly ash by suspending the solid reactants in a NaCl-AlCl3 melt at 530–850°C and then sparging chlorine into the melt has been investigated. A mechanically agitated, semi-batch reactor was used to test the effects of temperature, oxide and carbon loading, salt composition and gas flow on the reaction rate. The process was modeled using the carbochlorination of pure alumina, the rate of which was found to be chemical reaction controlled at temperatures below about 650°C and gas-liquid mass transfer controlled at higher temperature. The carbochlorination rate of the mixed oxides in coal fly ash was also mass transfer controlled at higher temperatures when aluminum recoveries were less than about 50%. At higher aluminum recoveries, the overall rate was limited by the rate of ash dissolution into the melt.

Time-dependent leaching of coal fly ash by chelating agents

1983 ◽  
Vol 17 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Wesley R. Harris ◽  
David. Silberman
Keyword(s):  
Fly Ash ◽  
Chelating Agents ◽  
Coal Fly Ash ◽  
Time Dependent

scholarly journals CARS Temperature and LDA Velocity Measurements in a Turbulent, Swirling, Premixed Propane/Air Fueled Model Gas Turbine Combustor

1995 ◽  
Author(s):  
Stephan E. Schmidt ◽  
Paul O. Hedman
Keyword(s):  
South Carolina ◽  
Gas Turbine ◽  
High Efficiency ◽  
Flame Structure ◽  
Gas Temperature ◽  
Velocity Measurements ◽  
Turbine Engine ◽  
Engineering Research ◽  
Brigham Young University ◽  
Systems Research

This paper present results from a research program being conducted at the Advanced Combustion Engineering Research Center (ACERC) at Brigham Young University (BYU). This study is part of a comprehensive effort supported by the Advanced Gas Turbine Systems Research (ATS) Program headquartered at the South Carolina Energy Research and Development Center, Clemson, South Carolina. The objective of this study was to characterize a turbulent premixed propane/air flame in a model combustor that simulates the characteristics of a utility gas turbine engine. The program’s long term goal is to develop and commercialize ultra-high efficiency, environmentally superior, and cost competitive gas turbine systems for base-load applications in the utility, independent power producer, and industrial markets. This paper focuses on the following four areas of the investigation: 1) a series of digitized video images to document the effect of fuel equivalence ratio and swirl number on flame structure, 2) LDA velocity measurements to quantify the flow structure, 3) CARS gas temperature measurements to determine the temperature field in the combustor, and 4) local continuity and energy release in differential elements throughout the flame zone.

Independent Effects of Surface and Gas Temperature on Coal Flyash Deposition in Gas Turbines at Temperatures Up to 1400°C

2015 ◽  
Author(s):  
Robert Laycock ◽  
Thomas H. Fletcher
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Particle Temperature ◽  
Combined Cycle ◽  
Capture Efficiency ◽  
Threshold Temperature ◽  
Gas Temperature ◽  
Independent Effects

Deposition of coal flyash in gas turbines has been studied to support the concept of integrated gasification combined cycle (IGCC). Although particle filters are used in IGCC, small amounts of ash particles less than 5 μm diameter enter the gas turbine. Previous deposition experiments in the literature have been conducted at temperatures up to about 1288°C. However, few tests have been conducted that reveal the independent effects of gas and surface temperature, and most have been conducted at gas temperatures lower than 1400°C. The independent effects of gas and surface temperature on particle deposition in a gas turbine environment were measured using the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Gas temperatures were measured with a type K thermocouple and surface temperatures were measured with two-color pyrometry using the RGB signals from a camera. This facility was modified for testing at temperatures up to 1400°C. Subbituminous coal fly ash, with a mass mean diameter of 4 μm, was entrained in a hot gas flow at a Mach number of 0.25. A nickel base super alloy metal coupon 2.5 cm in diameter was held in this gas stream to simulate deposition in a gas turbine. The gas temperature (and hence particle temperature) governs the softening and viscosity of the particle, while the surface temperature governs the stickiness of the deposit. Two tests series were therefore conducted. The first series used backside cooling to hold the initial temperature of the deposition surface (Ts,i) constant at 1000°C while varying the gas temperature (Tg) from 1250°C – 1400°C. The second series held Tg constant at 1400°C while varying the initial Ts,i from 1050°C to 1200°C by varying the amount of backside cooling. Capture efficiency and surface roughness were calculated. Capture efficiency increased with increasing Tg. Capture efficiency also initially increased with Ts,i until a certain threshold temperature where capture efficiency began to decrease with increasing Ts,i.

scholarly journals Gas-Turbine Loading Schedule for Maximum Life of the Hot Gas Path Components

1970 ◽  
Author(s):  
Stanislaw Bednarski ◽  
C. N. Shen
Keyword(s):  
Plastic Strain ◽  
Thermal Shock ◽  
Gas Turbine ◽  
Firing Temperature ◽  
Thermal Fatigue ◽  
Computational Procedure ◽  
Time Dependent ◽  
Gas Temperature ◽  
Hot Gas ◽  
Loading Process

The paper describes development of a computational procedure for determining the optimal firing temperature schedule during loading of the gas turbine. It is assumed that the temperature has to be increased in a pre-determined time in a way that will minimize thermal fatigue deterioration of the turbine hot gas path elements. The gas temperature is constrained to lie between certain time-dependent limits all through the transient. The maximum plastic strain in a given loading process is taken as a measure of parts deterioration. The calculations performed are for hollow, stationary airfoils of a gas turbine, but the method is easily adaptable to full profiles and rotational airfoils as well as non-turbine applications where temperature is to be altered while thermal shock is to be minimized. A numerical example is given for illustration of the method.

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