A distributed activation energy model of heterogeneous coal ignition. Technical progress report, April 1-- June 30, 1995

PDF Version Also Available for Download.

Description

Experiments designed to measure kinetic rate constants of ignition of pulverized coals showed clearly that, for single particles or dilute suspensions, particle-to-particle variations due to reactivity and/or thermophysical properties are important. There exists ample evidence that the most important factor in interpreting these data is the existence of a variation in chemical reactivity in the sample. It is surprising, therefore, to note that all previous studies presumed that a single (average) activation energy is adequate to describe the ignition process. The equations formulated using this presumption are then correlated to the experimental measurements to infer the kinetic rate constants of ... continued below

Physical Description

24 p.

Creation Information

Chen, J.C. July 5, 1995.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 64 times , with 4 in the last month . More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

Experiments designed to measure kinetic rate constants of ignition of pulverized coals showed clearly that, for single particles or dilute suspensions, particle-to-particle variations due to reactivity and/or thermophysical properties are important. There exists ample evidence that the most important factor in interpreting these data is the existence of a variation in chemical reactivity in the sample. It is surprising, therefore, to note that all previous studies presumed that a single (average) activation energy is adequate to describe the ignition process. The equations formulated using this presumption are then correlated to the experimental measurements to infer the kinetic rate constants of ignition. The major objectives are to develop a model of heterogeneous ignition which allows for a distribution of activation energies, and to implement this model to interpret previously published data. It is the authors hypothesis that variations in chemical reactivity account for the experimental trends observed. Another objective of this project is to examine the effects of variations in thermodynamic and physical properties (e.g. specific heat, particle diameter, density) on data interpretation from previous ignition experiments. An attached paper submitted for review to ``Combustion and Flame`` summarizes the Distributed Activation Energy Model of Ignition, which accounts for particle-to-particle variations in reactivity within a sample by allowing for a distribution in activation energies among the particles and a single preexponential factor. The model captures the main characteristics of actual experiments, namely (1) the gradual increase in ignition frequency with increasing gas temperature and (2) the variation of the slope of the ignition frequency with O{sub 2} concentration. Finally, it has been shown that adjustments to the model parameters can be used to fit experimental data and extract reaction rate constants.

Physical Description

24 p.

Notes

OSTI as DE96000941

Source

  • Other Information: PBD: 5 Jul 1995

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Other: DE96000941
  • Report No.: DOE/MT/94013--T2
  • Grant Number: FG22-94MT94013
  • DOI: 10.2172/113915 | External Link
  • Office of Scientific & Technical Information Report Number: 113915
  • Archival Resource Key: ark:/67531/metadc622747

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • July 5, 1995

Added to The UNT Digital Library

  • June 16, 2015, 7:43 a.m.

Description Last Updated

  • Nov. 30, 2015, 7:40 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 4
Total Uses: 64

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

International Image Interoperability Framework

IIF Logo

We support the IIIF Presentation API

Chen, J.C. A distributed activation energy model of heterogeneous coal ignition. Technical progress report, April 1-- June 30, 1995, report, July 5, 1995; United States. (digital.library.unt.edu/ark:/67531/metadc622747/: accessed June 21, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.