Dissertation > Excellent graduate degree dissertation topics show

A Study on CFB Boiler Fly Ash Triboelectrostatic Separation

Author: WangQiMin
Tutor: YueGuangXi
School: Tsinghua University
Course: Power Engineering and Engineering Thermophysics
Keywords: CFB(circulating fluidized bed)boiler fly ash triboelestratic separation
CLC: TK229.6
Type: PhD thesis
Year: 2006
Downloads: 332
Quote: 0
Read: Download Dissertation

Abstract


With the increasing of total and unit capability of CFB boilers, more attention is paid to the disposal of fly ash from CFB boilers. The paper studied the feasibility of the triboelectrostatic separation method to separate the carbon in fly ash from CFB boilers, the influences of the operating conditions and equipment structure on the separating efficiency and the electrification characteristic of fly ash from the aerosol generator.The composition and component morphology in CFB boiler fly ash were found to be different from that of PC boilers by studying the evolution of the minerals in the coal in the middle temperature range in CFB boiler. The minerals in CFB boiler fly ashes keep the same crystal structure as that of the coals. The tracer elements usually adhere on the fly ash surface. The glass is rarely to be found in the fly ashes except for those coming from CFB boilers using limestone for desulphurization, and the galss and the crystle minerals combine together with obvious transition zone.The relative independent separating existence between carbon and the minerals in 10 CFB boiler fly ashes were studied with 3 different separating methods, i.e. the shaking screen, the gravity solution separation and the minimal fluidization separation. The carbon and the minerals in 8 fly ashes are proved to exist relative independently. So the triboelectrosatic carbon separation for most CFB boiler fly ashes is feasible. The separating device of CFB boiler fly ashes was designed and manufactured based on the achievement of the PC boiler fly ash triboelectrosatic separation technology. The 8 CFB boiler fly ashes, in which the carbon and minerals exist relative independently, were used to study the efficiency of the triboelectrosatic separation device.Experiment results show that the separating efficiency increases with theelectric field intensity increasing, feed air flow decreasing and the inlet width decreasing of the triboelectrosatic separation cell. The charge capacity distribution model, optimized with experiment data, for the mineral and carbon particles through a aerosol generator was presented, with which the multi-field in the separation cell was calculated. The comparisons of the calculation results and the experiment data proved that the model is reliable. At last, the influences of the air breakdown voltage, the coagulation of fly ash particles and relative independent separate degree between the minerals and carbon on separating efficiency of the triboelectrostatic separating process are discussed.The work in the paper shows that the triboelectrostatic separation is feasible, reliable and controllable method for disposal of fly ash from CFB boilers.

Related Dissertations

  1. Experimental Study and Mechanism Analysis on Particle Spray Agglomeration from Coal Combustion,X513
  2. Fly Ash study of low temperature ceramic foam,TU52
  3. Predicting Model of Coal Fired Fly Ash Resistivity,X701.2
  4. Research on the Modified Methods of Fly Ash for Ammonia-nitrogen Wastewater Treatment,X703
  5. 1200 tons automatic autoclaved fly ash brick molding equipment research and design of hydraulic systems,X705
  6. Research on Mechanical Properties of Concrete with Multi-Component Admixture,TU528
  7. Research on Early Age Shrinkage-Cracking Characterization of Concrete with Multi-Components Admixtures,TU528
  8. Test Research of Effects of Cement Content on Frost Resistance of Concrete,TU528
  9. Experimental Study on Treating Simulative Tannery Wastewater with Fenton-like System Constructed by Fly Ash,X794
  10. Research on Sodium Polyacrylate Water-retainingagent Modified by Bentonite and Fly Ash in Agriculture,TQ450.7
  11. The Study of Deep Treating for Dyeing Wastewater by Using Combination of Chitosan and Modified Fly Ash,X791
  12. Research on Modification of Fly Ash Fibers and Enhancement of Tensile Strength of Paper Made from Fly Ash Fibers,TS71
  13. Study on the Variation of Mercury Existing States in Fly Ash during Thermal Treatment Process,X773
  14. Experimental Study on Hg~0 Removal in Flue Gas by Fly Ash-CaO Adsorbent Combined with HBT Filter,X51
  15. Advanced Treatment of Oily Wastewater by Technology of Bacteriostatic Fly Ash Adsorption-Regeneration,X74
  16. Research on the Composite Silicate Thermal Insulation Material for External Wall,TU551
  17. Deep Treatment of Landfill Leachate by Modified Fly Ash Experimental Study,X703
  18. Experimental Study Saline Subbase with Calcium Carbide Dust,U412.22
  19. Marine research early age cracking of high performance concrete,TU528
  20. Chloride erosion and freeze-thaw cycles under high strength bond strength of fly ash concrete,TU528
  21. Study on the Performance of Alkali-activated Slag Cement under Seawater Corrosion,TU528

CLC: > Industrial Technology > Energy and Power Engineering > Steam Power Engineering > Steam boiler > Various types of boilers > Coal-fired boilers
© 2012 www.DissertationTopic.Net  Mobile