Combustion flames of boiler are produced as soon as gas fuel or the volatiles in the coal, liquid fuel which form droplets, solid fuel which form small particles are put together with air, after that they are ignited. Combustion flames can remain and pass on via the mixture among certain top and bottom restrictions of air/fuel proportions. These are recognized as the top and bottom flammability restrictions or explosive restrictions. Combustion flames of boiler are different generally between one fuel to other fuel and it is influenced by several conditions, for example pressure and temperature.
In case this kind of a mixture among the restrictions is comprised in a extended tube, the combustion flames will probably go alongside it at a certain velocity. This velocity differs from one fuel to other fuel, and it is influenced by the ratio of fuel/air and also actual conditions such as tube diameter, temperature, pressure, along with the way; down-wards or up-wards of combustion flame journey.
The velocity of combustion flames in the steam boiler are necessary in vaporizing and gas burners, especially in which element of combustion air is pre-combined together with fuel and goes directly into the furnace through a tube. When combustion flames velocity is higher than the mixture velocity within the pipe, the combustion flames could burn up again and also display returning down the supply pipe. Whenever, nevertheless, the combustion flames velocity is significantly lower compared to the mixture out via the burner, the combustion flames can remove through the nozzle and pick up-off. These results, generally known as light-again and raise-off are factors why attention should be obtained in switching burners coming from one particular fuel to a different.
Fuel/air mixes could build up in the boiler furnace or other limited area, and lead to an explosion when it is ignited. Commonly, the extra limited area will make higher impact of explosion. In case gas or oil burners, pulverized fuel drop ignition, serious attention should be obtained to make sure that the total system especially for combustible mixes should be carefully purged prior to an effort is designed to re-turn on the burner. Current programmed systems include flame malfunction recognition with specific purging specifications before any effort at re-ignition. Air fan is normally used to blow and purging through the furnace of steam boiler.
Combustion flames of boiler can be non-luminous or luminous. Coal and oil generate luminous combustion flames with orange color, although LPG and Natural Gas can burn produce non-luminous combustion flames with blue color. Luminous combustion flames are much better during heat transfer through radiation when compared with non-luminous combustion flames. The current steam boiler design enable combustion of any kind of fuel with no essential impact on total output or efficiency. Different designs committed to either oil or coal combustion might be susceptible to overheating on rear tube when fewer heats are shifted in boiler furnace if heating gas.