AS 3980:2016 pdf free download
AS 3980:2016 pdf free download.Determination of gas content of coal and carbonaceous material – Direct desorption method
The length and diameter of the canister shall be sufficient to accept the bore core or lump samples, with minimal air space to reduce the effect of changes in atmospheric conditions on the gas volumes measured. Splits and unreactive packing material may be used for ease of handling, and to protect the bore core from damage during transport.
The canister shall be sealed at one end and the other end shall have a removable gastight cap fitted with bi-directional, gastight valve. The cap is sealed by an O-ring or proprietary snap-lock coupling.
Where using splits, care shall be taken to ensure that securing is minimal and done in a way that does not allow the sample to become jammed in the canister at the time of removal, and so that it is unlikely that the outlet valve can be blocked by tape. Splits shall be secured at both ends and the middle to prevent expansion inside the canister.
The measurement of desorbed gas volumes is carried out by the water displacement method in the field and subsequently in the laboratory. The field measurement is directed towards determining the lost gas and the first portion of Q2 in desorption is used.
The following items of equipment are required:
(a) Measuring cylinder Graduated, glass or transparent plastics, of capacity appropriate to the desorption rate.
NOTE: Cylinders should be calibrated. AS 2163 provides tolerances for cylinders.
(b) Water reservoir Size appropriate to the cylinder used.
NOTE: The pan may need an over-flow at a sufficient height above the outlet level and the water level to be measured to correct for hydrostatic head unless a method/device is installed to provide a constant water level.
(c) Tubing Of plastic or rubber (preferably clear), flexible, durable, gastight and free of restricting bends and water traps. The tube is introduced into the measuring cylinders from the top (see Figure 5.1).
NOTE: Clear silicone rubber is favoured to allow easy detection of water traps and for minimization of maintenance. The volume of the tubing should be minimized.AS 3980 pdf free.
