Effect of cavitation on removal of alkali elements from coal
H Srivalli,L Nirmal,Rajarathinavelu Nagarajan +2 more
- Vol. 656, Iss: 1, pp 012107
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In this article, the authors extract alkali elements by cavitation effect using low-frequency ultrasound, in the presence of reagents (HNO3 and H2O2) in coal.Abstract:
The main impurities in coal are sulphur, ash and alkali. On combustion, the volatile forms of these impurities are either condensed on the boilers, or emitted in the form of potentially hazardous gases. The alkali elements present in coal help the fly ash particles adhere to boiler surfaces by providing a wet surface on which collection of these particles can take place. Use of ultrasonic techniques in cleaning of coal has stirred interest among researchers in recent times. Extraction of alkali elements by cavitation effect using low-frequency ultrasound, in the presence of reagents (HNO3 and H2O2) is reported in this paper. Powdered coal was dissolved with the reagent and exposed to ultrasonic fields of various frequencies at different time intervals. The treated solution is filtered and tested for alkali levels.read more
Citations
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Journal ArticleDOI
Mechanistic study of ultrasound-assisted solvent leaching of sodium and potassium from an Indian coal using continuous and pulsed modes of operation
H. Srivalli,R. Nagarajan +1 more
TL;DR: In this paper, fly ash particles travel along with flue gas and get deposited on heat transfer surfaces along the way, and Fouling and slagging are generated by fly ash and bottom ash.
Effect of sodium on deposition in a simulated combustion gas turbine environment
TL;DR: In this paper, the effect of gas phase alkali concentration on the adhesion properties of micronized coal has been studied using a laboratory-scale entrained reactor capable of accelerating the combustion products of an injected coal-air mixture to the velocities observed in a combustion gas turbine.
Journal ArticleDOI
Ash removal from bitumen using ultrasonic falling film contactor
Maryam Dehbani,Masoud Rahimi +1 more
TL;DR: In this paper, an Ultrasonic Falling Film (USFF) contactor has been proposed as a novel technology for enhancing ash removal from natural bitumen, which is based on difference in hydrophilicity and hydrophobicity of particles, and the most significant reason for positive effect of USFF is micro cavitation bubbles which play a role of producing bubbles in froth flotation technology and carry hydrophobic particles to the free surface.
Book ChapterDOI
Acoustic Cavitation as Process Intensifier: A Phenomenological Study
TL;DR: In this paper, Cavitation-induced destratification has been investigated as a mechanism to remove ash, sulfur and alkalis from coal prior to combustion, thereby greatly mitigating the downstream propensity for slagging, fouling, corrosion and erosion.
References
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Journal ArticleDOI
Atmospheric emissions and pollution from the coal-fired thermal power plants in India
TL;DR: In this article, the authors show that aggressive pollution control regulations such as mandating flue gas desulfurization, introduction and tightening of emission standards for all criteria pollutants, and updating procedures for environment impact assessments, are imperative for regional clean air and to reduce health impacts.
Journal ArticleDOI
Ultrasonic coal-wash for de-sulfurization.
TL;DR: Conventional chemical-based soaking and stirring methods are compared here to ultrasonic methods of de-sulfurization, which have the main advantages of ultrasonic de-Sulfurized over conventional methods, the mechanism involved in ultrasonicDe-solfurization and the difference between aqueous-based and solvent-based (2N HNO(3), 3-volume percentage H(2)O(2)) de-magnifying methods are investigated experimentally.
Journal ArticleDOI
Effect of sodium on deposition in a simulated combustion gas turbine environment
TL;DR: In this paper, the effect of gas phase alkali concentration on the adhesion properties of micronized coal has been studied using a laboratory-scale entrained reactor capable of accelerating the combustion products of an injected coal-air mixture to the velocities observed in a combustion gas turbine.