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1 edition of Relative spontaneous heating tendencies of coals found in the catalog.

Relative spontaneous heating tendencies of coals

Relative spontaneous heating tendencies of coals

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Published by U.S. Govt. Print. Off. in Washinton .
Written in English

    Subjects:
  • Coal -- Analysis.,
  • Combustion, Spontaneous.

  • Edition Notes

    Statementby J.L. Elder ... [et al.]
    SeriesTechnical paper - United States. Bureau of Mines ;, 681, Technical paper (United States. Bureau of Mines) ;, 681.
    ContributionsElder, James Lowry, 1909-
    Classifications
    LC ClassificationsTN1 .U6 no. 681
    The Physical Object
    Paginationii, 24 p. :
    Number of Pages24
    ID Numbers
    Open LibraryOL6492160M
    LC Control Number45036699
    OCLC/WorldCa16934432

    oxidation potential, crossing point temperature for determination of susceptibility of 31 Indian coals to spontaneous heating. They used 10 mg coal sample of particle size mesh,, in oxygen atmosphere with a flow rate of 20 ml min-1, the heating rate was at o. C min-1, between ambient to o. C and with alumina as reference material. Coal mine fire is a major issue not only in India but also all over the world. But around 80% coal fires occurring in Indian coal mines are due to spontaneous heating of coal. Due to coal fire many precious lives are lost, and economical loss also occur to the organization and to the nation. With.

    How it Works: SponCom determines the coal's rank and relative self-heating potential based on the coal's proximate and ultimate analyses, heating value, and prior spontaneous combustion history. The coal's proximate and ultimate analysis is critical to generating an accurate, valid report. Two mechanisms contribute to heat generation by the. 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.

      It acts as a catalytic agent. •The high moisture coals have higher tendency of spontaneous heating. •Nandy et al. () had shown that there is an optimum moisture level of around 5% in coal showing maximum spontaneous heating tendency. h. Oxygen content •The liability of coal to sp. heating is directly related to its O2 content. The SHT is a measure of a coal’s reactivity, and is calculated based on the method established by Smith and Lazzara () using coal analysis data. The relative self-heating tendency of coal is determined based on its SHT value. To prepare the coal for testing, lumps of fresh coal are passed through a jaw crusher and then sieved.


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Relative spontaneous heating tendencies of coals Download PDF EPUB FB2

Additional Physical Format: Online version: Relative spontaneous heating tendencies of coals. Washington: U.S.G.P.O., (OCoLC) Material Type. Spontaneous ignition is also a factor in coal waste bank fires. Although the spontaneous combustion of coal has been studied extensively, there is very little information about the self‐heating tendency of roof coals and carbonaceous shales.

This study of self‐heating tendencies utilized a modified version of a differential thermal analyzer. The relative self-heating tendencies of 24 coal samples were evaluated in an adiabatic heating oven.

Minimum self-heating temperatures (SHT's) in the oven ranged from 35/sup 0/C for a lignite and high-volatile C bituminous coal, to /sup 0/C for two low-volatile bituminous coals.

Although the spontaneous combustion of coal has been studied extensively, there is very little information about the self-heating tendency of roof coals and carbonaceous shales.

This U.S. Bureau of Mines study of self-heating tendencies utilized a modified version of a differential thermal analyzer. Ann G. Kim, in Coal and Peat Fires: A Global Perspective, Spontaneous Combustion. Spontaneous combustion in the coal or coal refuse is related to the oxidation of the coal to form CO 2, CO, and H 2 O.

The oxidation of pyrite and the adsorption of water on the coal surface also are exothermic or heat-generating reactions that increase the probability of spontaneous combustion.

SPONTANEOUS COMBUSTION STUDIES OF U.S. COALS. This report describes a series of laboratory studies carried out by the Bureau of Mines to evaluate the relative self-heating tendencies (SHT) of 24 coal samples. It was found that the SHT of a coal increased when the coal. Relative spontaneous heating tendencies of coals book report describes laboratory studies conducted by the Bureau of Mines on the spontaneous combustion of U.S.

coals. Approximately 11 pct of U.S. underground coal mine fires are attributed to spontaneous combustion. The relative self-heating tendencies of 24 coal samples were evaluated in an adiabatic heating oven. An empirical expression was determined predicting a bituminous coal's.

1. Introduction. Coal mine fires have been a great concern both for the industry and researchers worldwide. Studies carried out by different researchers reveal that in most of the cases, they are caused by spontaneous heating of coal (Feng et al.,Saghafi and Carras,Sensogut and Cinar, ).It is known that all coals, when exposed to air, undergo natural oxidation even at.

In Indian coal mines 80% of the coal fires occur due to spontaneous combustion. The main aspect of starting the fire in India is that the coal seams are thicker and there is a tendency of spontaneous heating during the depillaring operation.

The problem of extraction. Coal oxidation at low temperatures is the heat source liable for the self-heating and spontaneous combustion of coal. This phenomenon has imposed severe problems in coal related industries.

To determine the relative self-heating tendencies of coals, coal refuse, and carbonaceous shales, a combination of differential thermal analysis (the sample temperature is measured relative to a standard) and crossing-point temperature (the point at which the sample temperature equals or exceeds a reference temperature) methods was used.

The Role of Sorption of Water Vapor in the Spontaneous Heating of Coal. Fuel, v. 50,pp. The Role of Desorption of Moisture From Coal in Its Spontaneous Heating. Fuel, v. 51,pp. 8- Bylo, Z., and B. Polchlopek. (Effect of Moisture on the Results of the Determination of Spontaneous Heating Tendencies of Coal.).

Approximately 11 pct of U.S. underground coal mine fires are attributed to spontaneous combustion. The relative self-heating tendencies of 24 coal samples were evaluated in an adiabatic heating oven.

Minimum self-heating temperatures (sht's) in the oven ranged from 35 deg c for a lignite and high-volatile c bituminous coal, to deg c for two.

However, in abandoned coal mines and waste banks, initiation and propagation of fires may be strongly dependent on the self-heating tendency of these materials.

The purpose of the study was to compare the self-heating probability of carbonaceous shales and coal wastes to that of coals. In the environments of various open coal storage sites, mining-affected coalbeds, and goafs, etc., some coal bodies are often affected by external environmental factors.

They are highly prone to spontaneous combustion in low moisture content (≤8%). In order to examine the effect of low moisture content on the spontaneous combustion tendency of coals with different metamorphic grade, we.

a case of "if" you will have a PRB coal fire, it's "when." Spontaneous combustion of coal is the process of self heating resulting eventually in its ignition without the application of external heat. It is caused by the oxidation of coal. If the rate of dissipation of heat is slow with respect to the evolution of heat by oxidation there will.

The beginning of spontaneous combustion is characterized by the self-heating temperature (TSN), which is a minimum in terms of experience, the temperature at which the heat dissipation is detected. When reaching in the process of self-heating a certain temperature, called ignition temperature (Tcvos), there is a burning of the material.

Article Study on spontaneous combustion tendency of coals with different metamorphic grade at low moisture content based on TPO-DSC Jiuyuan Fan 1, Gang Wang 1,2,*, Jiuling Zhang 3 1 Shandong University of Science and Technology, College of Mining and Safety Engineering, QingdaoPR China ; [email protected] (J.F.).

This study presents a review of the various methods to predict the spontaneous combustion liability of coal and coal-shale. The relative propensity of coal to undergo self-heating can be established by different methods.

These methods are well established in their usage, but the fact that no particular test method has become a standard to predict the spontaneous combustion liability. Their high moisture content, greater tendency to combust spontaneously, high degree of weathering, and the dusting characteristics restrict widespread use of such coals.

The price of coal sold to utilities depends upon the heating value of the coal. Thus, removal of moisture from low-rank coals (LRC) is an important operation. Spontaneous combustion: Coal has a tendency to self-heat due to the auto-oxidation of its compounds, making spontaneous combustion the most common cause of uncontrolled burning.

There are thousands of uncontrolled coal fires across the earth, some of which have been burning for thousands of years.Soon, as the heating rate increases in intensity to about degrees F, incipient combustion, and ultimately self-ignition and flame, will occur.

Spontaneous combustion has long been recognized as a fire hazard in stored coal. Spontaneous combustion fires usually begin as "hot spots" deep within the reserve of coal.There are different methods for estimating coal strength and hardness: compressive strength, fracture toughness, or grindability, all of which show a trend relative to rank, type, grade, and petrography of the coal.

Friability and previous oxidation of the coal are also important factors in the self‐heating (spontaneous combustion) process.