What are the variables that affect the combustion process of biomass boiler fuel?

I. Water content

The water content of different fuels varies greatly, depending on the fuel type and storage method. In order to maintain the combustion stability of biomass boiler fuel, it needs to be aired before use (a dry shed should be added when conditions permit). The increase of water content will reduce the heat storage temperature of the furnace and increase the incomplete combustion of fuel in the combustion chamber. Excessive water content is the main reason why the national energy biomass power plant can't carry the load.

II. The calorific value

The general factors affecting calorific value are water, ash and impurities in fuel, which is also a common problem in domestic biomass power plants (it is difficult for biomass power generation enterprises to develop unless the problem of excessive water and ash in fuel is solved). Too wet and too long fuel is blocked in the reclaimer and feeder, and can't be burned completely on the grate, which increases the incomplete combustion loss (a power plant can't carry high load for a long time because the ash content of fuel entering the furnace is usually more than 40%).

III. The excess air coefficient

The ratio of theoretical air volume to actual air volume is called excess air coefficient. 

The combustion excess air coefficient of biomass boiler should be greater than 1, usually greater than 1. 25, to ensure the full mixing of combustion-supporting air and combustible materials. 

The excess air coefficient follows the data of pulverized coal boiler, and there is no authoritative demonstration now. The actual boiler combustion should be oxygen-enriched combustion because of the high volatile matter and fast combustion speed of biomass.

IV. The air temperature

The hot air of the boiler in biomass power plant is heated by the water from deaerator, so it is necessary to raise the air temperature as much as possible to promote the high-end fire of the grate.

V. Fuel types

The different characteristics of different fuels affect the combustion process, among which the main influencing factors are fuel composition, volatile and fixed carbon content, thermal performance, density, porosity, size and active surface.