1 research outputs found
Effect of the Heat Transfer Surface on Prevention of Spontaneous Combustion of Coal
The increased use of coal for power
generation has increased the demand for low-rank coal, such as lignite and
sub-bituminous coal, and during its supply, it may need to be stored for long
periods. Because low-quality coal is more susceptible to spontaneous combustion
than high-quality coal, its storage could potentially cause work-related
accidents. One method being developed to control the temperature of stored coal
to prevent spontaneous combustion is the immersion of heat exchangers in coal
piles. This method can be used to control the temperature during both the
storage and transportation processes. The purpose of this study was to test
this method and, in particular, study the effect of changes in the
heat-exchange surface area on the effectiveness of temperature control. An
experiment was set up to control the temperature of a laboratory-scale coal
pile using a heat exchanger made from copper tubes. Coal samples were placed in
a cylindrical container with a spiral-shaped heat exchanger, placed in the
center of the cylindrical container, and cooled with ~27o seawater.
Tests were carried out using several configurations of heat exchanger
dimensions to determine the effect of changing the ratio of heat-exchange
surface area to volume of combustible material. The test results showed that
greater heat-exchange surface area produced a greater amount of cooling load
and temperature difference