The combustion air will be heated to the flame temperature. This heating cost money. If you have some waste heat to be used for preheating the combustion air it will pay.
The condensing boiler burns carbon-based fuel with oxygen in order to produce steam and carbon dioxide. The gases that escape this process (through a chimney) as exhaust are called flue gases. The major advantage is that they offer up to a 90% improvement in terms of efficiency when compared to standard gas boilers. Overall, condensing boilers are considered much more efficient in contrast to non-condensing gas boilers, a major consideration for any business running on a budget.
The characteristics of dust collector of coal-fired boiler:
1) Separating the particulate matters. The dust collector of coal-fired boiler can effectively separate the big particulate matters with ignition conditions, so as to reduce the obstruction of dust removal system and improve efficiency.
2) Reducing dust. The dust collector of coal-fired boiler can prevent the dust-contained gas from washing the bag to lower the dust concentration of dust-contained gas and extend the service life of filtering bag and pulse magnetic valve.
3) Adopting materials with high quality. The dust collector of coal-fired boiler adopts high-temperature resistant materials that can extend the service life of dust collector.
4) Adopting elastic piston ring. The mouth of filtering bag adopts elastic piston ring to ensure the leakproofness, which is firm and reliable.
It could also say, how much heat is required to rais the water temperature from 60 ℃ to 90 ℃.
To calculate heat required follow below steps
Q= mCp dt
Where
m - water flow rate (kg/hr)
Cp- specific heat of water
dt- temperature differences ( 90–60)
You will get heat required in kcal/ hr.
dividing to Q by fuel GCV and system efficiency you will come to know how much fuel (either it is coal or oil) required to raise the temperature of water from 60 ℃ to 90℃.
1.Primary air is used for transportation of fine coal particle from coal mill to boiler floor at different elevations as per requirement.
2.Primary air is used for preheating of moisturised coal in to the coal mill so that minimum energy is required for combustion of the same.
3.As we all know that only 23% oxygen is available in the air by weight. For combustion of huge quantity of coal inside the boiler very high quantity of oxygen is required. This oxygen requirement will be completed by secondary air which is supplied by FORCED DRAFT fans through ducts.
This secondary air is coming via air preheater hence its outlet temperature increases this will help in combustion and low heat input is required for combustion of coal.
Boiler efficiency is mainly depended on the amount of losses in the system. In high capacity pulverized coal fired boilers the total losses account to about 12 to 14%. Roughly 50% of the losses are governed by fuel properties like hydrogen in fuel, moisture in fuel and ambient air conditions. The other 50% losses are carbon loss and dry gas loss. The best efficiency in the boiler can be achieved if the losses are kept to the minimum. Since 50% of the losses are dependent on the fuel and ambient condition, the best efficiency can be achieved by properly tuning the other 50%, i.e. mainly carbon loss and dry gas loss.
The coal-fired steam boiler is a forced circulation high-pressure single-tube DC boiler. Its operation process includes three processes: the combustion process of the fuel, the heat transfer process of flue gas to water and the vaporization process after water absorbs heat. In order to better control these different processes, the control system should make
the heat of pulverized coal combustion adapt to the requirements of steam load changes and dryness.
If you smell gas, don’t use electrical switches, telephones, or any appliances that may cause sparks.Firstly, you should shut off the gas valve, open the doors and windows to circulate the air. Then you should seek for professional help:
