Principle of Solid Fuel FiringPublished on 24/2/2012 and last updated on 9/8/2018
There are two methods available in solid fuel firing.Please Rate this Article
Hand FiringHand firing technique can handle the boiler of small output. Here, we feed coal into the furnace with shovels. The primary and secondary air for combustion we control with dampers. The grate of such type of boilers consists of vertical iron bars over which we feed the coal.
Mechanical Stoker FiringHere the feeding of fuel is done by mechanical stoker. There are many advantages of mechanical stocker firing over hand firing. We can feed the coal fuel uniformly into the furnace. We can control the combustion much easily. We can manage the fluctuation of load demand by controlling the coal combustion. We can quickly increase the output of the boiler by feeding more coal for burning. By controlling primary and secondary air, we can burn poor-graded coal efficiently as well. This method reduces labour cost much as there is no need for additional human workers to feed fuel to the boiler. There are two types of mechanical stoker firing available. These are under feed stokers and travel grate stockers.
Under Feed StokersHere, coal gets burnt on the grate. The primary combustion air is fed to the grate. The secondary air is allowed at the top. Here the burnt out fuel is pushed forward by fresh fuel with the help of rams or screws on the fuel bed. The ignition occurs downwards against the primary air flow. The volatile matters get filtered through the bed, and it is totally burnt out. If the rate of the combustion of fuel is high enough, the ash contents are picked up by primary air along with the combustion gases and get delivered to the atmosphere. When fresh fuel is fed into the bed, most of the ashes move along the grate and fall into the ash pit.