A study of techniques for reducing ash deposition in coal-fired gas turbines

Logan, R.G.; Richards, George; Meyer, Charles T.; Anderson, Rodney J.

doi:10.1016/0360-1285(90)90031-w

Cited by 15 publications

(10 citation statements)

References 5 publications

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“…The high levels of alkali retention have been confirmed for low dosages of additives (1%) [15]. A bituminous coal was tested on a combustion entrained reactor with the additive of kaolin and emathllte by Ronald G et al They found both additives were effective in reducing sticking coefficients at 1100-1300°C [16]. A forestry residue biomass had been tested on a pilot-scale (35 MW) circulating fluidised bed (CFB) boiler with an additive of kaolin at a relatively low temperature for a continuous operating of seventeen days.…”

Section: Introductionmentioning

confidence: 82%

Inhibition of lignite ash slagging and fouling upon the use of a silica-based additive in an industrial pulverised coal-fired boiler. Part 1. Changes on the properties of ash deposits along the furnace

Dai

Girolamo

et al. 2015

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103

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Section: Introductionmentioning

confidence: 82%

Inhibition of lignite ash slagging and fouling upon the use of a silica-based additive in an industrial pulverised coal-fired boiler. Part 1. Changes on the properties of ash deposits along the furnace

Dai

Girolamo

et al. 2015

Fuel

103

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“…The main role of additives in a boiler is to minimize deposit accumulation by reducing the concentrations of low-melting compounds, increasing the melting temperature of the deposits, and decreasing the strength of the deposits so that they can be removed easily [4]. Kaolin has been proved to react reversibly with alkali elements to decrease the strength of fouling deposits by lowering ash sticking coefficient [5][6][7]. Similar to kaolinite, emathlite also reacts reversibly with alkali elements and therefore retains highest amount of sodium [6].…”

Section: Introductionmentioning

confidence: 99%

“…A plausible reason is the chemical reaction between the alkali salts-particularly chlorides-and the aluminosilicates. Hence, various studies have been reported trials with bentonite [1], kaolin [1,6], emathlite [6], magnesia [4], calcium trisilicate [7], Fuller's earth [8], magnesium oxide (MgO) [9], aluminum [10], pumice stone [1], alumina [11], etc., which are potential additives in trapping alkali elements in ash. In all of these studies, additive performance was tested in a laboratory-scale burner rig or in a fluidized bed combustor.…”

Section: Introductionmentioning

confidence: 99%

Suitability of laser-induced breakdown spectroscopy in screening potential additives to mitigate fouling deposits

et al. 2016

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Alkali vapors present in the flue gas generated during coal-based combustion form fouling deposits as they condense. An additive added to coal can trap alkali elements in ash, therefore suppress the growth rate of fouling deposits, and increase thermal efficiency of a coalfired thermal power plant. Laser-induced breakdown spectroscopy (LIBS) technique is proposed and demonstrated to screen potential additives to trap alkali elements in ash. Five additives-namely, kaolinite, alumina, silica, magnesia, and pumice-were analyzed for their effectiveness on four Indian coals for retaining/confining alkali elements in ash during coal combustion. Ratio analysis based on LIBS emission intensity values clearly shows that kaolinite and pumice are promising additives to trap sodium. Similarly, kaolinite, pumice, and silica exhibited good potassium retention.

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“…If the cooling holes are blocked from the deposition, the effectiveness of the TBC system becomes even more important. Deposits in the turbine section from fly ash become molten in the combustor and adhere to the to the first stage turbine vanes [22]. Figure 9 shows the path of the deposition created by Logan et al [22].…”

Section: Chapter 4: Review Of Relevent Literaturementioning

confidence: 99%

“…Deposits in the turbine section from fly ash become molten in the combustor and adhere to the to the first stage turbine vanes [22]. Figure 9 shows the path of the deposition created by Logan et al [22]. Deposits can also form due to the intake of volcanic ash.…”

Section: Chapter 4: Review Of Relevent Literaturementioning

confidence: 99%

Degradation of thermal barrier coatings on an Integrated Gasification Combined Cycle (IGCC) simulated film-cooled turbine vane pressure surface due to particulate fly ash deposition

Luo¹

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Coal synthesis gas (syngas) can introduce contaminants into the flow of an Integrated Gasification Combined Cycle (IGCC) industrial gas turbine which can form molten deposits onto components of the first stage of a turbine. Research is being conducted at West Virginia University (WVU) to study the effects of particulate deposition on thermal barrier coatings (TBC) employed on the airfoils of an IGCC turbine hot section. WVU had been working with U.S. Department of Energy, National Energy Technology Laboratory (NETL) to simulate deposition on the pressure side of an IGCC turbine first stage vane to study the effects on film cooling. To simulate the particulate deposition, TBC coated, angled film-cooled test articles were subjected to accelerated deposition injected into the flow of a combustor facility with a pressure of approximately 4 atm and a gas temperature of 1560 K. The particle characteristics between engine conditions and laboratory are matched using the Stokes number and particulate loading [1]. To investigate the degradation on the TBC from the particulate deposition, non-destructive evaluations were performed using a load-based multiple-partial unloading micro-indentation technique and were followed by scanning electron microscopy (SEM) evaluation and energy dispersive X-ray spectroscopy (EDS) examinations. The micro-indentation technique used in the study was developed by Kang et al. [2] and can quantitatively evaluate the mechanical properties of materials. The indentation results found that the Young's Modulus of the ceramic top coat is higher in areas with deposition formation due to the penetration of the fly ash. The increase in the modulus of elasticity has been shown to result in a reduction of strain tolerance of the 7% yttria-stabilized zirconia (7YSZ) TBC coatings [3]. I would like to extend my gratitude to Dr. Bruce S. Kang and his Ph.D. student Dumbi A. Otunyo for providing the multiple partial unloading indentation system. Without guidance and use of the system, I would not have been able to perform a quantitative strain tolerance analysis. I've had the pleasure of having Dr. Kang as a supportive figure in my life since I was a young lad at Christian & Missionary Alliance (C&MA) Church.

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A study of techniques for reducing ash deposition in coal-fired gas turbines

Cited by 15 publications

References 5 publications

Inhibition of lignite ash slagging and fouling upon the use of a silica-based additive in an industrial pulverised coal-fired boiler. Part 1. Changes on the properties of ash deposits along the furnace

Inhibition of lignite ash slagging and fouling upon the use of a silica-based additive in an industrial pulverised coal-fired boiler. Part 1. Changes on the properties of ash deposits along the furnace

Suitability of laser-induced breakdown spectroscopy in screening potential additives to mitigate fouling deposits

Degradation of thermal barrier coatings on an Integrated Gasification Combined Cycle (IGCC) simulated film-cooled turbine vane pressure surface due to particulate fly ash deposition

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