|Infobox on Coal|
|Example of Coal|
|Stowage factor (in m3/t)||-|
|Humidity / moisture||-|
Coal, a fossil fuel, is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide anthropogenic sources of carbon dioxide emissions. Gross carbon dioxide emissions from coal usage are slightly more than those from petroleum and about double the amount from natural gas. Coal is extracted from the ground by mining, either underground by shaft mining through the seams or in open pits.
All classes of coal are liable to spontaneous combustion when carried in bulk, the softer types to a greater extent than others. Adequate ventilation of holds is essential to minimize the risk. If damaged by heating or combustion, the affected portion should be segregated from the remainder to prevent spread of the damage.
Most classes of coal, particularly those to be used for coke-making, and of coke will suffer deterioration or depreciation in value by contact with salt water although quality, calorific value apart, is seldom affected by contact with fresh water. Particular care must be exercised in arriving at depreciation or loss arising from spontaneous combustion, heating or water damage.
The effects can range from a decrease in calorific value to a significant change in the suitability of the coal/coke for its original purpose. The assistance of a qualified sampler/analyst is essential to determine the degree of deterioration or loss.
Coal or coke shipped in a wet condition may be subject to loss of weight due to drainage during the voyage or by evaporation, up to say 3% depending on the quantity shipped. However, loading and discharging of these materials in heavy rain could result in an increase in discharged weight over shipped weight. Apart from the physical weighing of the commodity on loading and discharging, an approximate check of the lost or added weight can be made by using the immersion scale of the vessel or by comparison of the moisture analysis of cargo samples taken professionally during loading and discharging.
Cargo weights are in certain cases ascertained at points remote from ship’s rail or alternatively at the time the cargo was put into stock on quay or in barge. It is in these cases that variation between the weight indicated as shipped and actually loaded will occur. The loading, transportation and discharge of coke results in some degree of breakage, leading to a smaller average size of lumps and a greater content of fine material, breeze and dust.
Careful sampling and testing according to standardized procedure are necessary to determine the extent of these changes. Total quantities can be checked accurately only if the moisture content is known while the size analysis affects the value of coke for all saleable purposes.
Reference is made to the relevant IMO regulations on hazardous cargo.
Full information on this product is in the process of completion.