CaltechTHESIS
  A Caltech Library Service

Experimental studies of char oxidation and fume formation from pyrite

Citation

Li, Xiaoming (1992) Experimental studies of char oxidation and fume formation from pyrite. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-08072007-075230

Abstract

Pulverized coal combustion is nowadays the most commonly used technology for power generation from coal. The detailed understanding of the coal combustion process is of fundamental importance to the design of more economic and efficient combustion devices and to the control of gaseous and particulate pollutant emission. This thesis presents an experimental study of (a) thermally induced changes of char structure and their effect on its combustion reactivity and (b) the mechanism of ash formation under conditions pertinent to pulverized coal combustion.

Pyrolyzed or partially oxidized coal char was generated in a drop-tube furnace from a Pittsburgh seam hvA bituminous coal (PSOC 1451). The char was characterized by elemental analysis and N2 adsorption for specific surface area and pore volume distribution to better understand the influence of oxygen and residence time on the char structure. The reactivities of chars produced under different oxygen contents and residence times were examined by oxidation in a thermogravimetric analyzer. The conversion of the combustible material at high temperature was measured using ash as a tracer.

The pyrolysis and combustion of pyrite particles were studied with an electrodynamic balance and a drop-tube reactor. Two types of pyrite were examined, a natural pyrite (85% purity) and a synthetic pyrite (99.9% purity). Fume particles formed from individual pyrite particles were observed directly in electrodynamic balance experiments. The drop tube reactor experiments allow measurements of the fume particle concentration and size distribution. The nature of the fume was characterized using a Transmission Electron Microscope equipped with energy dispersive X-ray analysis. Physical mechanisms that might lead to the release of iron rich fragments were investigated.

Item Type:Thesis (Dissertation (Ph.D.))
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Environmental Science and Engineering
Thesis Availability:Restricted to Caltech community only
Research Advisor(s):
  • Flagan, Richard C. (advisor)
  • Gavalas, George R. (co-advisor)
Thesis Committee:
  • Flagan, Richard C. (chair)
  • Gavalas, George R.
  • Morgan, James J.
  • Hoffmann, Michael R.
Defense Date:30 August 1991
Record Number:CaltechETD:etd-08072007-075230
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-08072007-075230
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3036
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:10 Aug 2007
Last Modified:26 Dec 2012 02:56

Thesis Files

[img] PDF (Li_x_1992.pdf) - Final Version
Restricted to Caltech community only
See Usage Policy.

5Mb

Repository Staff Only: item control page