is combustible substance, in which the combustion produces a large amount of heat.
Fuel
The ______ can be used for various domestic and industrial purposes.
heat
________ fuels are non-renewable energy resources which were stored up millions of years ago by photosynthesis.
Fossils
such as coal, oil, natural gas, and uranium are naturally
available, hence are called ________ ______.
natural fuels
These natural fuels are processed through chemical or physical
activities, producing ________ ______
secondary fuels
The fuel selected should be most suitable for the process. For example, coke made out of bituminous coal is most suitable for blast furnace.
Suitability
The fuel should possess ________ _________ ______ because calorific value determines the efficiency of the fuel. Higher is the amount of heat per unit mass or volume, better the fuel.
High Calorific Value
is the lowest temperature to which the fuel must be
heated so that it starts burning smoothly. A good fuel should have moderate ________ _________.
ignition temperature.
If the fuel has low ___________ ___________, the storage and transportation become dangerous, since it can cause fire hazards. If, on the other hand, the ___________ __________ is too high, the transportation and storage become easier, but it causes difficulty in kindling.
ignition temperature, ignition temperature,
_____________ content should be low because presence of high moisture lowers
the effective calorific value of the fuel.
Moisture content
________________ ________ _________ forms clinker after combustion. The presence of non-combustible matter reduces the heating value and also involves the cost of
disposal after combustion.
Noncombustible matter content
____________ _________ ____should be moderate. Too high velocities of
combustions are not required, whereas too low velocities cause loss of heat due to radiation.
Velocity of combustion
The fuel should have a low cost and should be available in large amount at a cheap rate.
Cost of fuel
The products formed should not be harmful. The gaseous products
evolved during combustion should be such that they do not cause unpleasant odors and other harmful effects.
Nature of the product
Formation of _______ should be as low as possible.
smoke
The fuel should be such that its combustion can easily be controlled, that is, it can be easily started or stopped.
Control of the process
