Fuel & Furnaces (Lab) “Standard Method of Test for Swelling Index of Coal ”
Submitted by: Muhammad Arslan Afzal 2007MET14
Submitted to: Mr. Abdul Khaliq Sb.
WWW.07MET.TK Date: 251008
Standard Method of Test for Swelling Index of Coal Introduction This is a small-scale laboratory test. By this method we can obtain information about free swelling properties of a coal.
Crucible: This translucent silica, low form, with silica ring handle lid, conforming to the following requirement, also an extra pierced lid for use in determining the crucible temperature; Weight = 11 to 12.75g External height = nearly 26 mm Internal diameter at base = 11mm Capacity (approx.) = 17 cm sq. Sight Tube : this is for viewing the cock buttons, so that the affect of parallax will be eliminated. The tube shall be made of any rigid and preferably opaque material and shall be supported vertically on the ring stand. Burner Assembly: A gas burner with a grid of external diameter 30 to 42mm, a draft shield, and a triangular crucible are used here.
Calibration With burner assembly and empty crucible, light the burner about 15min before making a determination to allow the draft shield to raise an equilibrium temperature. After placing a crucible in position adjust the flow of gas and relative positions of the burner and the draft shield so that temperature of the inner surface of the bottom of the crucible reaches nearly 800 C in 1.5 min and 820C in 2.5min. Setting the draft shield so that the bottom of the crucible is approximately 10mm, above the burner grid, and then adjusting the gas flame may usually obtain the desired temperature. Determine the crucible temperature by mean of a thermocouple and a potentiometer. Insert the thermocouple through the pierced crucible lid so that the unprotected junction of the thermocouple and a portion of each wire are in contact with the base of the crucible.
Preparation of the Sample Grind the sample of coal to pass a 250 micro (No.60) sieve, and prepare it in accordance with the requirements of ASTM methods D.271, laboratory sampling and analyses of the coal and coke. The size consists of the sample is variable which can affect size of coal button produced.
Procedure 1- I weighed 1g of prepared sample of coal and coke in cold crucible 2- I leveled the crucible by slightly tapping on solid surface 3- I covered the crucible by solid lid and placed it upright in the draft shield, directly on gas flame
WWW.07MET.TK 4- I heated the covered crucible for 20min so that volatile matter may burn out. 5 I removed the coke button carefully and also removed the carbon residue remaining in crucible by ignition
MEASUREMENT OF COKE BUTTON By viewing the coke button through sight tube and comparing it with standard profile, place the standard profile in front of eye, rotate the button on its axis to take maximum cross-sectional area to view. Record the numbers of profiles, which are comparable to cross-sectional area of button coke as its swelling index. In our experiment the swelling index number is = 11/2 by comparing it with standard profile.
Some coal gives buttons that don’t 11/2 conform in shape to the standard profile, for such purposes measure the maximum cross-sectional area of buttons and determine the index. If residue is coherent but non swelling then place it on flat surface and put a weight of 500 g, if button disintegrates then its index will be one and half, and if not integrated then its index will be one.
Applications The result may be used as indication of caking characteristics of the coal when burnt as fuel.
“Standard Method of Test for Swelling Index of Coal ” Submitted by: Submitted to: Muhammad Arslan Afzal 2007MET14 WWW.07MET.TK Mr. Abdul K...