What factors affect the combustion resistance of biomass fuels?

1. The main factors affecting the combustion resistance of biomass fuel
Humidity: Humidity is one of the important factors affecting the combustion resistance of biomass fuels. High humidity will increase the moisture in the biomass fuel, thereby reducing its combustion temperature and combustion rate.
Particle size and density: Fuels with coarser particles or lower density are less flammable when burned, and have a small surface area, making it difficult to release heat and gases, resulting in slow combustion. In addition, when the density of the fuel block is insufficient, it will also make it difficult for oxygen to penetrate deep into the fuel during the combustion process.
Cellulose content: The higher the cellulose content in biomass fuel, the better its burning resistance. Because cellulose is one of the main fuel components in biomass fuels, its combustion temperature and rate are relatively high.
Ash content: The higher the ash content in biomass fuel, the worse its burning resistance. Because the ash will absorb the heat released during combustion, thereby reducing the combustion temperature and rate of biomass fuel.
Chemical composition: The chemical composition of a biomass fuel also affects its resistance to burning. For example, biomass fuels with higher contents of lignin and fatty acids have higher combustion temperature and rate, while biomass fuels with higher contents of phenols and aldehydes tend to produce smoke and harmful substances.

2. What are the meanings of fixed carbon, volatile matter, and ash that are often said in the industry? What is the relationship between them and the burning resistance of biomass fuels?

Fixed carbon refers to the carbon that is not completely oxidized during the combustion process. It is an important fuel component and one of the energy sources of fuel. The generation of fixed carbon is due to the fact that during the combustion process, the carbon in the fuel cannot be completely oxidized at high temperature, forming a black residue, that is, fixed carbon.

The content of fixed carbon depends on the type of fuel and combustion conditions. Generally speaking, biomass fuels such as wood and coal have higher fixed carbon content. The fixed carbon in biomass fuel comes mainly from cellulose in plant cell walls. Cellulose is a high molecular polysaccharide composed of glucose molecules, which is one of the main components of plant cell walls. During plant growth, glucose produced by photosynthesis is converted into cellulose, which is stored in the plant's cell walls. When biomass fuel is burned, the carbon in the cellulose is released to form fixed carbon.

Cellulose in biomass fuel is closely related to volatile matter. Cellulose is the main structural polysaccharide in biomass, accounting for most of the total mass of biomass, and it is composed of a large number of glucose molecules. Volatile matter is the non-structural organic matter in biomass, including lignin, hemicellulose, and low molecular weight organic matter. In the process of biomass combustion, cellulose needs to be decomposed into volatile matter and carbon by pyrolysis reaction, and then the volatile matter can be further burned to release energy. Therefore, cellulose and volatile matter interact and influence each other in the combustion process of biomass fuel. At the same time, the content and properties of cellulose and volatile matter in biomass fuels will also affect factors such as combustion efficiency, emissions, and environmental pollution.

The ash content of biomass fuel refers to the residue of non-combustible substances in biomass during the combustion process. These non-combustible substances include lignocellulose, lignin, hemicellulose, inorganic salts, and the like. These substances are not completely combusted during combustion and therefore remain to form ash.

The causes of ash in biomass fuels include:

1. Biomass contains non-combustible substances, such as lignin, hemicellulose, etc.

2. Biomass may contain some impurities, such as soil, sand, etc.

3. During the combustion process, some elements in the biomass (such as calcium, magnesium, potassium, etc.) will be oxidized into inorganic salts, and these inorganic salts will remain in the ash.

In short, the ash content of biomass fuel is produced because the non-combustible substances in biomass cannot be completely burned during combustion.

3. What is the relationship between fixed carbon, volatile matter and ash?

Fixed carbon, volatile matter and ash are the three main components in biomass fuels, and the content relationship among them affects the combustion characteristics and energy efficiency of biomass fuels.

The contents of fixed carbon, volatile matter and ash are interrelated and can be expressed by the following formula:

Fixed Carbon + Volatile Matter + Ash = 100%

Among them, fixed carbon is the part of biomass fuel that is difficult to gasify at high temperature, ash is the part that cannot be gasified during combustion, and volatile matter is the part that is volatile and can be decomposed into gaseous and liquid states at high temperature.

In general, as the fixed carbon content of biomass fuels increases, the volatile and ash contents decrease accordingly. When we want to increase the flammability of biomass fuels and increase the calorific value of fuels, biomass fuels with reduced fixed carbon content and increased volatile content should be considered. When we improve the wear resistance and compression resistance of biomass fuels, we should choose biomass fuels with higher ash and fixed carbon content. Therefore, when selecting biomass fuels, the appropriate biomass fuels should be selected according to different needs.

4. Are the higher the fixed carbon and volatile matter in biomass fuel, the more resistant to burning?




Biomass fuels with higher fixed carbon content are more resistant to burning. This is because fixed carbon is the substance left after biomass combustion, which has high thermal stability and oxidation resistance, and can exist for a long time at high temperature without being burned. Therefore, biomass fuels with higher fixed carbon content will generate higher heat, longer burning time and higher combustion efficiency during combustion.

Biomass fuels with high volatile content burn with higher heat, but they also burn to completion more easily, so they may burn for a shorter time. Conversely, biomass fuels with low volatile content may take longer to burn completely, but they may burn longer. Therefore, there is no direct relationship between the volatile content of biomass fuels and their combustion resistance.

5. What factors affect the calorific value of biomass fuel, and what is its relationship with fixed carbon content, volatile matter and ash content?

The calorific value of biomass fuel is affected by the following factors:

1. Moisture content: The higher the moisture content, the lower the calorific value.

2. Carbon content: The higher the carbon content, the higher the calorific value.

3. Oxygen content: The lower the oxygen content, the higher the calorific value.

4. Nitrogen content: The higher the nitrogen content, the lower the calorific value.

5. Sulfur content: The higher the sulfur content, the lower the calorific value.

The calorific value of biomass fuel has the following relationship with fixed carbon content, volatile matter and ash content:

1. Fixed carbon content: The higher the fixed carbon content, the higher the calorific value.

2. Volatile content: The higher the volatile content, the lower the calorific value.

3. Ash content: The higher the ash content, the lower the calorific value.