Influencing factors of slagging on heating surface of boiler
(1) Ash characteristics of pulverized coal
Generally, the softening temperature ST of ash is used as the main indicator of slag formation. Coal with low ash melting point (ST<1200℃) is easy to slag. In addition, the slagging index also includes: silicon ratio, alkali-acid ratio, slagging index, limit viscosity and so on.
（2）Aerodynamic characteristics in the furnace
Improper air flow organization leads to flame center deviation, and the pulverized coal air flow flame adheres to the wall, causing local slagging of the water-cooled wall;
Improper air flow organization, forming flue gas retention vortex area and forming a reducing atmosphere (with CO), reducing the ash melting point and increasing the possibility of slagging.
Excess air coefficient: When the excess air in the furnace is too small, a reducing atmosphere may be generated, and the tendency of slagging will increase accordingly.
（3）Influence of boiler heat lo
1. During the start-up process of the burner, if the burner repeatedly alarms and locks, it should be found out the reason, find the fault and eliminate it, and then press the reset button to inherit the start. Note: The continuous press of the reset button should not exceed 10 seconds
2. If the burner is not successful in one combustion, the natural gas boiler induced draft fan should be restarted, and the second combustion can be started after 5 minutes of ventilation.
3. In the normal operation era, the burner close to the thermal equipment department (such as the connecting flange, etc.) will be very hot, to prevent the formation of burns. Do not place flammable materials in the vicinity to avoid causing fire.
4. During the operation of natural gas-fired boilers, it is necessary to closely supervise the working conditions of hot water circulation pumps and natural gas-fired boiler pressures, natural gas distribution bags, pipeline valves, pressure gauges, flow meters, and water
The fuel of a gas-fired boiler is gas such as natural gas, city gas, biogas and liquefied gas, etc. What kind of fuel the boiler burns is decided by an equipment called a burner. The boiler equipped with a gas-fired burner is called a gas-fired boiler. There are three methods of gas-fired boiler combustion as per technical characteristics of how the gas and air mix.
1. Diffusion combustion:
Gas and air mutually diffuse at the gas nozzle and are burning. The advantages are burning stably and with simple burner structure. However, the heated area is easy to be carbonized due to long flame, which is easy to produce incomplete combustion.
2. Premixed combustion:
A part of air and gas are premixed before combustion (coefficient of primary air surplus is between 0.2-0.8), and then being burned. The advantages are clear combustion flame, enhanced combustion, and high thermal efficiency.
If the boiler burner fails or is faulty, then your boiler is not going to be able to generate heat efficiently, or in the worst case not at all . As industrial boilers are in almost constant use they are built to be very robust and last for decades, nevertheless they can still have problems with broken burners from time to time. Burner pumps, heads and nozzles can all cause problems but a swift replacement should limit your down time.
Not inspecting it often enough can lead to minor issues being missed, which can lead to major issues later and possibly injury.
Not checking a boiler system could have catastrophic results in the form of a boiler explosion. Fuel may explode due to unfound problems. The high temperatures generated by the boiler can also cause problems if the water level drops too low and the trip switch fails.
Regular inspections can identify and correct faults in the safety systems that are designed to prevent accidents.
When it comes to regular maintenance, the cost of the inspections and repairs will be dramatically lower than the loss of time and profit from a broken boiler that requires replacing. Don’t let maintenance fall by the wayside. Schedule it at even intervals throughout the year.
Normally a boiler is provided with two independent sensors for emergency low water level burner cut-outs. So this would never happen. However, if it does, don't take any chances! Shut off the burners immediately!
Before you start raising the level in the boiler you have to find out if any part of the furnace walls has been overheated. If you raise the level over a glowing steel-wall then the boiler might produce more steam than the safety valves can handle and a nasty explosion would be the result.
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.
