What is swelling of coal?

Coal swelling is observed when one or both of the gases (carbon dioxide or methane) are sorbed into the coal matrix. Similarly, coal shrinkage is observed when one or both of the gases (carbon dioxide or methane) are desorbed.

How do you calculate swelling index?

Determination of swelling index

Fill the cylinder up to 20 ml mark with water. Agitate gently occasionally during 24 hour and allowed to stand. Measure the volume occupied by the swollen. The genuine seed of isapgol occupies a volume of not less than 10 ml.

What is caking index of coal?

caking index. measure of the magnitude of the binding strength between coal particles or between coal particles and inert particles after coal is heated at 850 °C.

What is swelling index of soil?

DEFINITION • Free Swell Index is the increase in volume of a soil, without any external constraints, on submergence in water.

What is free swelling?

Free swell or differential free swell, also termed as free swell index, is the increase in volume of soil without any external constraint when subjected to submergence in water.

What is importance of swelling index?

The swell index test procedure is used to determine the general swelling characteristics of bentonite clay. The Swell Index test has not been demonstrated to have a proportional correlation to hydraulic properties, a high swell is considered by most to be a good indicator of bentonite quality.

What do you mean by Free Swell Index?

The free-swelling index (FSI) is a measure of the increase in volume of coal when heated under specified conditions (ASTM D720; ISO 335). The FSI method is a small-scale test for obtaining information regarding the free-swelling properties of a coal.

What is the use of Free Swell Index test?

Free swell tests are commonly used for identifying expansive clays and to predict the swelling potential. The method as proposed by Holtz and Gibbs suffers from inaccuracies in volume measurement of dry powder in air.

What are the 4 grades of coal?

Coal is classified into four main types, or ranks: anthracite, bituminous, subbituminous, and lignite. The ranking depends on the types and amounts of carbon the coal contains and on the amount of heat energy the coal can produce.

What is ARB and ADB in coal?

ADB – Air-Dried Basis. In coal sample analysis, ADB neglects the presence of moistures other than inherent moisture while DB (dry-basis) leaves out all moistures, including surface moisture, inherent moisture, and other moistures. ARB – As-Received Basis.

What is free swelling value?

What is the purpose of Free swell Index?

Objective: Free swell or differential free swell, also termed as “free swell index”, is the increase in volume of soil without any external constraint when subjected to submergence in water.

What is the purpose of Free Swell Index?

What are the units of Free Swell Index?

Determine Free Swell Index Of Soil

Free Swell Index Degree of expansiveness PL
<20 Low 0-35%
20-35 Moderate 25-50%
35-50 High 35-65%
>50 Very high >45%

What is swelling value?

The swelling value can be calculated by using the following formula: Swelling (%) = (Ws – Wd)/Wd × 100. Where. Wd= Weight of polymer. Ws= weight of swollen polymer.

Which grade coal is best?

Anthracite: The highest rank of coal. It is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter. Bituminous: Bituminous coal is a middle rank coal between subbituminous and anthracite.

Is Gar and GCV same?

Coal quality can be measured in GAR (Gross As Received), ARB (As Received Basis) or GCV (Gross Calorific Value, measured in Kcal/Kg), which are essentially the different names for the same metric.

What is GCV and NCV of coal?

The calorific value of the fuel is the amount of heat or energy a fuel generates during complete combustion. It is the variable of the heat or energy released, which is either measured in Gross Calorific Value (GCV) or Net Calorific Value (NCV).

What are the units of Free swell Index?

What is free swell test?

What is the difference between swell and shrinkage?

Shrink–swell is the volume change that occurs as a result of changes in the moisture content of clay-rich soils. Swelling pressures can cause heave, or lifting of structures, whilst shrinkage can cause settlement or subsidence, which may be differential.

What are the 4 types of swelling?


  • Peripheral edema: This affects the feet, ankles, legs, hands, and arms.
  • Pulmonary edema: This occurs when excess fluid collects in the lungs, making breathing difficult.
  • Cerebral edema: This occurs in the brain.
  • Macular edema: This is a serious complication of diabetic retinopathy.

What are the 3 types of coal?

What are the different types of coal?

  • Anthracite, or “hard coal,” contains the highest amount of carbon out of all coal ranks (86%-97%)1.
  • Bituminous coal, often called “soft coal,” has slightly lower carbon content than anthracite (45%-86%)1.
  • Subbituminous coal does not have the same shiny luster as higher ranked coals.

What is the unit of GCV?

The GCV shall be determined based on the ISO 6976:1995 method or its subsequent revisions, on dry basis, with rounding to the first full digit. Its unit of measurement is kcal/m³ (kilocalorie per cubic meters).

Why GCV is higher than NCV?

Answer: This is because,NCV (net calorific value) is the quantity of heat produced by combustion when the water produced by combustion remains gaseous. Since water releases heat when it condenses, GCV is clearly bigger than NCV.