In general, gas-fired boiler uses natural gas to heat water in order to provide heat source for underfloor heating and heating radiator, while condensing gas-fired uses condensation technology to recycle the thermal energy from the exhaust gas.
With the industrial innovation and the advance of science and technology, steam engine is replaced by gas-fired boiler that is a kind of more energy-saving heat production machine. There are three main usages of gas-fired boiler that we need to know in order to better understand the benefits that gas-fired boiler brings to us.
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
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
Industrial boilers will produce wastes that needs to be treated during the use process, which is what we mentioned of boiler blowdown. What are the methods for boiler blowdown?
1. Regular blowdown
1) The time interval and quantity of discharge depend on the test results of boiler water. It usually do not exceed 5% of the water supply.
2) When the regular blowdown is being made under high load of the boiler, the blowdown of the water-cooled wall header is generally not required to avoid affecting the normal water circulation of the water-cooled wall and forming a tube explosion incident.
2. Continuous blowdown
The amount of blowdown shall be determined according to the test results of the boiler water, and shall be completed by adjusting the needle-shaped angle of the blowdown tube.
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.
