In the adjustment of boiler operation, on the basis of ensuring safe operation, economic operation must also be achieved to improve boiler efficiency. In general boiler units, the efficiency can basically reach more than 92%, and the total loss is less than 8%. The loss is: exhaust heat loss, generally 5-6%, followed by mechanical incomplete combustion heat loss is less than 1-1.5 %, heat loss and ash slag physical heat loss are about 1%. (Physical heat loss for high ash coal ash residue will be greater).
From the point of view of quantification of indicators, the key to improving boiler efficiency is to reduce smoke loss and heat loss due to incomplete combustion of machinery. Pay attention to the flue gas temperature changes. Excessive flue gas temperature will affect the efficiency of the boiler. Too low temperature may cause low-temperature corrosion of the air preheater. Therefore, it is necessary to strengthen the adjustment according to the load changes during operation. When t
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
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.
The explosion-proof door of the gas-fired boiler is opened or broken when the combustible gas explosion suddenly increases the pressure, it then releases high-pressure gas to reduce the damage to the gas-fired boiler body and also ensure
The function of the gas-fired boiler explosion-proof door is usually reflected when the gas-fired boiler is ignited or running due to improper operation. For instance, the furnace is not purged before ignition, the furnace is still not purged even the ignition cannot successfully be lit, the nozzle is leaking, the fuel is not completely burned, and extinguished failure to cut off fuel quickly, etc. all of them may cause the furnace and tail flue to explode. Installing explosion-proof door for gas-fired boiler is to release the pressure to avoid the accident from expanding and also to ensure the safety of the industrial steam boiler when a slight explosion occurs in the furnace or flue.
Here load means, amount of steam drawn from the boiler. So when the load increases, the specific volume of the steam in the boiler increases reducing the pressure. This inturn demands for more feed water and more amount of fuel to be burnt. So, for any boiler there will be a feed water level control system put in place to measure the water level in drum. As and when the level of water in the drum reduces, the controller sends a signal to the feed water pump to start and stops when the desired water level is reached. This way the steam generation continues to maintain the desired pressure.
A water level sensor fail on a steam boiler is extremely dangerous. The low water cut of should be tested daily. If the sensor fails the boiler could turn all the water into steam, leaving the boiler dry. Without water in the boiler the flame from the burner would heat up the heating surface to extreme temperatures and would crack and damage the inside of the boiler. But that’s not the dangerous part. If water added to boiler while it is extremely hot. Once water touches the extremely hot heating service, water would immediately start to evaporate into steam. When water evaporates it expands 18x it’s original size. The boiler would explode from the sudden increase in pressure from the inside. Some in some cases, boilers that have exploded out of a building and have landed 100s of feet away.
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.
Missing insulation reduces the system’s efficiency. Insulation helps hold heat in the system, and when the heat can dissipate, more fuel is needed to maintain proper temperature and pressure.
Since missing insulation may not be visible, the best way to detect it is with a thermal imager. If you don’t have a thermal imager as a part of your building’s operations, a plumber or other professional likely will carry one. If your energy costs have increased without a rise in the amount you use the boiler, suspect missing insulation and call to have the system inspected with a thermal imager.
