ISO 540:2008 pdf download

ISO 540:2008 pdf download.Hard coal and coke – Determination of ash fusibility.
The method for determination of the fusibility temperatures of coal ash and coke ash described in ISO 540 provides information about the fusion and melting behaviour of the composite inorganic constituents of the ash at high temperatures. The standard method is based on the “Seger Cone” method, which is well known in the ceramic industry, the use of which predates the year 1900. The conditions of the test, as well as basic studies on the influence of ash chemistry and of gas composition on ash fusibility temperatures (which have led to the standardization of the method), arose from the pioneering work of Fieldner, Hall and Field (J.
In the laboratory, the ash used for the test is a homogeneous mixture prepared from a representative sample of the coal or coke, and the determination is performed at a controlled rate of heating in either a reducing or an oxidizing atmosphere. In contrast, under industrial conditions, the complex processes of combustion and fusion involve heterogeneous mixtures of particles, heating rates (that can be several orders of magnitude greater than those used in the standard test) and variable gas composition.
During the first quarter of the 20th century, laboratory, pilot-scale and field studies were undertaken to establish that the ash fusibility test can provide a reasonable indication of the propensity of ash to form fused deposits (referred to as cIinker”) in stoker and other fuel-bed type furnaces (Nicholls and Selvig [2]). Subsequently, the test has been used as a general indicator of the tendency for ash to fuse on heating and of ash slagging propensity in pulverized coal-fired furnaces.
A test piece made from the ash is heated under standard conditions and continuously observed. The temperatures at which characteristic changes of shape occur are recorded. The characteristic temperatures are defined in Clause 3. (See also Figures 2, 3 and 4.)
Although the determination is usually performed in a reducing atmosphere, additional information can sometimes be obtained by performing a further determination in an oxidizing atmosphere. In general, the reducing atmosphere in 7.1 gives the lowest characteristic temperatures.
6.1 Furnace, electrically heated, which satisfies the following conditions.
a) It shall be capable of reaching the maximum temperature at which the properties of the ash are determined (a temperature of 1 500 °C or more can be required).
NOTE Some furnaces can have a practical upper operating temperature, e.g. 1 480 or 1 540 DC, due to the type of heating elements used in their manufacture.
b) It shall provide an adequate zone of uniform temperature in which to heat the test piece(s).
c) It shall provide means of heating the test piece(s) at a uniform rate from 815 °C upwards.
d) It shall be capable of maintaining the required test atmosphere (see 7.1) around the test piece(s).
e) It shall provide a means of observing the change of shape of the test piece(s) during heating.
It is recommended to provide a facility for inserting, between the end window of the furnace and the optical viewing instrument, a piece of cobalt-blue or similar glass to protect the retina of the operator from radiation emitted at elevated temperatures.ISO-540-2008

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