Reasons and solutions to coking in the combustion of biomass pellets

Biomass pellet produced by biomass pellet mill is the main energy source to replace coal. However, when the pellets burned, the phenomenon of coking occurs sometimes. Then, how does the phenomenon of coking occur and how to solve it?


 
Reasons for coking in the combustion of biomass pellets produced by biomass pellet mill:
1. Ash and impurities in the pellets.
The main factors affecting the heat of biomass pellets in the combustion are the chemical composition of ash after combustion and the surrounding high temperature environmental media, which influence mutually. If the combustion furnace is adjusted, it will affect its combustion and form incomplete combustion coking. In addition, when making biomass pellets with biomass pellet mill, there would be some sand and soil in the raw materials, which would affect the melting temperature, aggravating coking phenomenon.
 
2. Internal surface temperature of combustion furnace.
In the case of a certain melting point of ash, the temperature and distribution in the furnace are also the causes of coking. The coking is mostly in the flue and superheater surface. Affected by the heat movement, ash particles with faster movement has poor cooling effect that it is easy to adhere to the surface. The slag layer accumulates quickly, thus forming coking. The results show that the higher the temperature of combustion chamber, the higher the coking index.
 
Methods to solve the coking phenomenon of biomass pellet fuel produced by biomass pellet mill:
1. Conventional solution.
In the past, pellets produced by biomass pellet machine are mainly used in power plants. The steam jet blower is mainly used to clean the coking and ash on the heating surface, but the effect is not ideal. High pressure water cleaning treatment can only be used after stopping the furnace.
 
2. New cleaning methods.
At present, the method of combining decoking inhibitor and pulsed gas blowing device is adopted to deal with the coking and ash accumulation of boiler. The decoking inhibitor (SlagTr011508) is a kind of fuel additive with high melting point and combustible agent, which can reduce the deposition of fly ash. With the pulsed gas blowing device, the accumulated ash on the heating surface of the boiler can be removed by purging, sound fatigue, thermal cleaning and local vibration beating, and the dust can be carried away by the smoke air flow, so as to improve the thermal efficiency of the boiler.
 
In order to improve the operation efficiency of boiler and ensure the normal operation of production, the use of coke removal inhibitor (SlagTr011508) and pulse gas blowing device can effectively solve the problem of boiler ash coking.
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