Click here to make tpub.com your Home Page

Page Title: Spontaneous Oxidation and Heating of Coal
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 



SPONTANEOUS HEATING/IGNITION
OF HYDROCARBONS AND ORGANICS
DOE-HDBK-1081-94
Spontaneous Heating and Pyrophoricity
raise the material to the temperature range of 50 to 75 C (122 to 167 F), where the living
organisms die. Beyond this point, oxidation reactions must take over if ignition is to occur.
The existence of biological heating requires careful control of moisture, air supply, and
nearby combustible or flammable materials. If a "hot spot" in a pile of organic material
comes in contact with a highly flammable liquid or gas, a fire or explosion may occur. Heat
generated by biological action may also act as a catalyst for other reactions which occur only
at elevated temperatures.
The likelihood of biological heating may be reduced by the following measures:
Provide adequate ventilation of the organic material to remove moisture, heat, and
dust particles.
Limit the storage time of the organic material using a "first in, first out" rule of
thumb.
Circulate large quantities of organic materials to disperse areas of localized heating.
Appendix A lists many organic materials known to heat spontaneously and measures to
prevent their ignition.
Spontaneous Oxidation and Heating of Coal
Coal presents hazards between the time it is mined and its eventual consumption in boilers
and furnaces. Below are listed some of the characteristics of spontaneous fires in coal.
These characteristics can be used to evaluate the potential for coal fires and as guidelines for
minimizing the probability of a fire.
1.
The higher the inherent (equilibrium) moisture, the higher the heating tendency.
2.
The lower the ash free Btu, the higher the heating tendency. The higher the oxygen
content in the coal, the higher the heating tendency.
3.
Sulfur, once considered a major factor, is now thought to be a minor factor in the
spontaneous heating of coal. There are many very low-sulfur western subbituminous
and lignite coals that have very high oxidizing characteristics and there are high sulfur
coals that exhibit relatively low oxidizing characteristics.
4.
The oxidation of coal is a solid/gas reaction, which happens initially when air (a gas)
passes over a coal surface (a solid). Oxygen from the air combines with the coal,
raising the temperature of the coal. As the reaction proceeds, the moisture in the coal
is liberated as a vapor and then some of the volatile matter that normally has a distinct
odor is released. The amount of surface area of the coal that is exposed is a direct
factor in its heating tendency. The finer the size of the coal, the more surface is
Pyrophoricity
Page 10
Rev. 0


Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business