Steam generation in a boiler

 AS discusses earlier section boiler is a machine that generated steam at a desires pressure and temperature. In a boiler fuel burn in a furnace to get heat energy which is convert chemical energy in a heat energy store in fuel. This heat is utilised to produce steam from the water. Different type of fuel use in a boiler and according , the boiler designed. In water tube boiler water tube is arranged around the furnace and the path the flue gasses. In this tube feed water is circulated. Water tube is arranged in close system by the boiler drum. Feed water come in tube by water drum and after take heat energy to vaporize and went in drum. Due to different density , water is circulated in these tube naturally

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                                               Water circulation is divide into two type first is natural circulation and second is force circulation.                    

              In a force circulation circulation is given by

                                                    F = ρcH₁ - ρcH₂

Where, ρc = density of cold water, ρc = density of hold water
A force circulation boiler is a boiler where a pump is used to circulate water inside the boiler.
               The force circulation boiler being the same as a natural circulation boiler, at the feed water pump water is introduced into the steam drum and is circulation around the boiler, leaving only as steam what makes the force circulation boiler different its use of a secondary pump that circulation water through the boiler. The secondary pump takes the feed water going to the boiler and rises the pressure of the water going in.

A boiler drum filled with a fresh feedwater. The feed water before entering into the drum is heat at the economiser which placed at the flue gas path. Most of the heat of flue gas is utilised inside the boiler . still considerable amount of heat energy is available in it. This heat is utilised in economiser to heat up the feed water. it is increase the efficiency of boiler.
                  For burning of fuel, the required oxygen is obtain from atmospheric air. air is supplied by force draught (F.D) fan . this air is heat by air heat before sent into the boiler furnace . if cold air is used , then there will be loss of energy. Air heater is place the path of the flue gasses.

 

 

Boiler system arrangement