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Tuesday, July 14, 2020 | History

3 edition of Effects of moisture on the spontaneous heating of stored coal found in the catalog.

Effects of moisture on the spontaneous heating of stored coal

S. H. Katz

Effects of moisture on the spontaneous heating of stored coal

by S. H. Katz

  • 308 Want to read
  • 12 Currently reading

Published by Govt. print. off. in Washington .
Written in English

    Subjects:
  • Coal

  • Edition Notes

    ContributionsPorter, Horace Chamberlain, 1876- joint author.
    Classifications
    LC ClassificationsTN1 .U6 no. 172
    The Physical Object
    Pagination25 p.
    Number of Pages25
    ID Numbers
    Open LibraryOL6612901M
    LC Control Number18026058
    OCLC/WorldCa29114127

    The effect of the moisture content on the coal heating value for different coal types is shown in Figure 6. The moisture in the coal can be categorized in three groups: the surface moisture (the free water), the physically bound moisture and the chemically bound moisture [32, 64].Cited by: 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 willFile Size: KB.

    This report describes the occurrence of spontaneous heating in an metric-ton heap of Wyoming coal. The major part of the report deals with the oxidation of Pittsburgh seam and Wyoming subbituminous coal and describes an experiment in which 1 metric ton of Wyoming coal is stored in a 5-meter-long insulated container while air is passed through. Pyrite oxidation is often the cause of coal spontaneous ignition in old mine tailings. Pistachio nuts are highly flammable when stored in large quantities, and are prone to self-heating and spontaneous combustion. Large manure piles can spontaneously combust during conditions of extreme heat. Cotton and linen can ignite when they come into.

    Assessing and managing spontaneous combustion of coal 4 Abstract This report summarises the most common, practical methods used to determine the propensity of coal to self-heat and considers the external factors which can combine to result in a spontaneous combustion event. Numerical Study on Effects of Coal Properties on Spontaneous Numerical study on effects of coal properties on spontaneous heating in longwall gob . exothermic. The moisture content of coal can play an important role in the content up to a value of 20% water (by mass) and then decreased with fur. More details» Get Price.


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Effects of moisture on the spontaneous heating of stored coal by S. H. Katz Download PDF EPUB FB2

This work investigates the effect of the moisture content of coal on its spontaneous ignition in oxygen (40 C C). It has been found that the highest heating rate is achieved at a medium moisture content of {approximately}7 wt% for an initial inherent moisture content of the coal before drying (in dry nitrogen at 65 C) of {approximately}20 wt%.

Excerpt from Effects of Moisture on the Spontaneous Heating of Stored Coal. There is no doubt a floating opinion among people accustomed to the handling of coal to the effect that moisture does increase the tendency to spontaneous combustion.

For coal reactivities lower than a critical value, the rate of heat generation remains lower than the rate of heat The effect of moisture condensation on the spontaneous combustibility of coal: S. Bhat and P. Agarwal 0 2 4 6 8 10 Time, hrs Figure 5 Effect of coal reactivity on the variation of particle temperature with by: moisture content relationship were included in the processes considered.

The results showed that the important processes in spontaneous heatings are the oxidation and the evaporation of moisture of coal. Conditions under which heaps of coal are likely to fire are determined. The results show that as the moisture increases, flame temperature and NO x mole fraction decrease, while O 2 mole fraction increases in the region near the burner, and the peaks of the flame temperature and NO x mole fraction shift by: application in the prevention of spontaneous combustion in underground coal mines.

Introduction. Spontaneous heating has long been a problem in the mining, storage, and transport of coal. Spontaneous heating is a low temperature coal oxidation reaction which takes place when coal is exposed to air. Pyrite has a significant effect on the spontaneous combustion of coal. The presence of pyrite can change the propensity of coal towards spontaneous combustion.

The influences of various pyrite contents on the parameters of spontaneous combustion, such as index gases, temperature and released heat etc., were investigated in this study. Coal Cited by: with 75% of the as-received moisture content present has an initial self-heating rate faster than the dried coal.

However, the sample with close to the as-received moisture content had a slower initial self-heating rate than the. 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 Cited by: 6.

When this method is used, the rain water flows down on the slopes of the stacked coal. In summer time, since the surface area exposed to the hot air is larger, drying effect becomes more significant.

At approximately 40–50% of the moisture holding capacity of the coal, the self-heating rate becomes measurable. Above this critical level of moisture content, the heat.

Additional Physical Format: Online version: Katz, S.H. (Sidney Hershberg), Effects of moisture on the spontaneous heating of stored coal. Washington: Dept. of the Interior, Bureau of Mines: Supt. of Docs. First, a paper on the effect of intrinsic coal properties on coal self-heating rates was presented inwhich covered a range of coal ranks from sub-bituminous C to lowvolatile bituminous.

stable coal-oxygen complexes until the critical tem-perature is reached. From then on, it is fairly safe to assume that an actual re incident will result. Factors a ecting the spontaneous combustion of coal The main reason for the di culties in under-standing the mechanism of spontaneous combustion is the presence of many internal and external fac.

('b) Heat Generated by O::d&\tion 13 (c) velocity, runbient humidity, arrl initial moisture content of tho coal. computer simulation of for eoal and ~hewed tho importance ot tbie effect on the t of ipontaneous he&tmg. o!' req_uired in order on storage in. Moisture in coal contributes to spontaneous heating because it assists the oxidation process.

Moisture content should be limited to 3 percent; sulphur content should be limited to 1 percent, “as mined.” Coal having high moisture content should be segregated and used as quickly as possible.

• If the coal is well graded, ensure sufficient airflow to dissipate excess heat • If coal in a bin self-heats, remove the coal and spread to cool • Coals may emit explosive gases –ensure good ventilation in confined spaces such as bins and silos • Coal must not be stored in bins and silos for long periodsFile Size: 1MB.

A high amount of moisture in coal is undesirable for a number of reasons: it may lead to spontaneous combustion when stored; it increases the stickiness of coal, resulting in blocked chutes and hang-ups in bunkers; it adds to storage and transportation costs, which are charged by mass; and finally, but not least, moisture reduces the heating.

The influence of stockpile height, slope angle of bed, particle diameter of coal, and coal moisture content on spontaneous heating of coal stockpile was investigated. Different degrees of compaction can be achieved and airflow rate varied to study the effects of varying rates of air permeation on the coal oxidation Size: KB.

It is imperative to have an in-depth understanding of the effect of extraneous moisture on the spontaneous combustion of coal not only for the control and prevention of coal spontaneous combustion in the coal mining industry, but also for the optimization design and application of the technological process.

In this study, the type of moisture in a coal body has been redefined. Given the right kind of coal, oxygen, and a certain temperature and moisture content, coal will burn by itself.

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.

The hot spots appear when coal absorbs oxygen from the Size: 87KB. Moisture content •Moisture inherent in coal, present in the surrounding oxidizing atmosphere, or produced from oxidation of coal in the early stages of oxidation influences the oxidation process.

It acts as a catalytic agent. •The high moisture coals have higher tendency of spontaneous heating.• In terms of spontaneous combustion testing the term ‘reactivity’ means the liability and/or propensity of coal towards rapid self heating • Any coal can oxidize and continue to self heat until either the reaction rate decreases or ignition occurs • This suggests that other factors may play a role in the chain of eventsFile Size: KB.