Discussion on boiler fuel
Thread Content
The boiler is fueled with Class A bituminous coal. The lower calorific value is generally 3500–5000 kcal/Kg. To increase the output of the boiler. Now, the calorific value of the fuel has been increased to 5500–6000. What are the requirements for the operation and maintenance of boilers? Let’s discuss it together.
Increase the primary air velocity, regularly check the combustion condition of the burners, frequently remove soot, adjust the boiler’s combustion process, and prevent steam from overheating.
1. Control the characteristics of the coal fed into the furnace, such as particle size and particle ratio, in order to improve combustion efficiency. 2. Regulate the primary air flow to ensure proper fluidization of the bed material, and control the ratio of secondary and tertiary air flows so that the material burns fully in the dilute phase region. 3. Improve the separation efficiency of the cyclone separator to ensure adequate return of ash
This question is too general; it would be more appropriate to discuss it in terms of the type of boiler
“To increase the output of the boiler. Now, the calorific value of the fuel has been increased to 5500–6000. ”I don’t understand: once the fuel is chosen, can its calorific value be increased just by wanting to?
It’s mainly about adjusting the air volume and the grate speed!
It doesn’t say it’s a circulating fluidized bed; what if it’s a coal powder furnace?
Control the boiler combustion; the more complete, the better
First of all, thank you all for your active participation. What I would like everyone to discuss is: what are the requirements for the operation and maintenance of boilers due to fuel replacement.
The calorific value increases, which means better coal is being used; if the boiler’s load does not increase and only the amount of slag produced decreases, there is no need to increase the air supply.
It is essential to pay attention to controlling the temperature of the heating surfaces in the furnace, as well as increasing the flow rate of the medium
The biggest problem is how to prevent coking.
The poster is probably referring to coal-fired boilers. Generally speaking, choosing coal with appropriate indicators can effectively prevent coking ； Second, control the thickness of the coal layer and the transmission speed of the grate, in order to maximize the combustion rate of the coal ； Third is controlling the air volume; generally, combustion should occur under slight negative pressure (that is, the amount of air drawn in is slightly greater than the amount of air blown in).
The wind speed and the rotation speed of the grate need to be properly controlled, with regular debris removal
The boiler is designed based on the type of coal we choose; therefore, the amount of heating surface it requires is fixed. If the calorific value of the fuel is too high, coking will occur even if the fuel consumption remains unchanged. Hence, it is necessary to adjust the air volume and control the speed of the grate. Increase inspections and closely monitor changes in the boiler water level.
I’m not sure what your original output was; it’s best not to operate the boiler beyond its capacity. The 110% load rating specified for the boiler refers to short-term overloading. Compared to coal with a high calorific value, coal with a low calorific value requires a thicker coal layer during combustion, a higher grate speed, greater volume of forced and induced air, and results in a lower furnace temperature. By making a comparison, one can know how to adjust it. Maintenance is primarily aimed at preventing the furnace temperature from rising too high, which could lead to coking inside the furnace and affect the boiler’s output. It can also easily cause damage to coal gates, chains, sealing blocks, etc., increasing the amount of maintenance required. It may also cause disorders in the water cycle
Adjust the air volume and grate speed properly.
This question is not specific enough; it would be better to list the coal quality characteristics, the boiler combustion method, the nozzle arrangement, and the ratios of primary, secondary, and tertiary air, among other factors, before discussing it.
With the change in fuel and an increase in calorific value, it is necessary to increase the air supply during operation, optimize the ratio of primary air to secondary air, and maintain the oxygen level inside the furnace. In terms of design, the burner was modified, and aerodynamic field tests were conducted again.