Wood pellets are a modern, environmentally friendly, and economically viable alternative to traditional fuels used for heating residential homes, businesses, and public buildings. Pellets can be made from various biomass materials, including energy crop wood, wood waste, bark, seeds, nutshells, and straw.
Calorific Value of Different Wood Pellets
As a clean and renewable energy source, biomass energy can reduce our dependence on fossil fuels and decrease air pollution. Compared to coal and diesel fuel, biomass energy has benefits such as renewability, high calorific value, low pollution levels, zero carbon emissions, and high density. Typically, biomass energy is used in forms such as biogas, ethanol, biodiesel, and biomass fuel.
Due to its low cost and ease of processing, biomass fuel has become popular on farms, in homes, and in rural areas. Biomass fuel comes in two forms: biomass briquettes and wood pellets. Due to their smaller size and higher density, wood pellets are easier to burn and more convenient to use, making them more popular.
The calorific value is an indicator of the quality of wood pellets. It is the amount of heat released per unit mass (or volume) of fuel when it is completely burned. The calorific value of wood pellets refers to the heat released by 1 kg of wood pellets. On average, the calorific value of wood pellets is 4400±100 kcal/kg, but it varies for different materials.
What Affects the Calorific Value of Wood Pellets?
In a word, the calorific value of wood pellets is determined by the raw materials from which they are made. Organic substances such as lignin, cellulose, starch, protein, and fat vary in different plants and different parts of the plant. In addition, the growth of plants is influenced by environmental factors such as climate, soil, and temperature.
Many people believe that the calorific value of wood pellets depends on their density and hardness. In fact, density refers to the weight per unit volume, while calorific value refers to the heat released per unit weight. The density of wood pellets has nothing to do with the calorific value. It only affects the volume of wood pellets. For a certain weight of wood pellets, regardless of the density, the value of their height is the same.
In summary, wood pellets have the following advantages:
- High calorific value, usually around 3800-4600 kcal/kg. After carbonization, the calorific value reaches 7000-8000 kcal/kg.
- High heat utilization rate. Wood pellets contain 75-85% carbon, 3-6% ash content, 1-3% moisture, without gangue or other substances that do not release heat.
- Environmentally friendly. Wood pellets do not contain sulfur or phosphorus, and no SO2 or P2O5 is released during combustion. At the same time, it is carbon neutral. Burning wood pellets will not cause boiler corrosion or lead to air pollution or acid rain.
- Clean and convenient. Due to their small and uniform size, wood pellets are easy to use. They can be fed into the boiler automatically, saving labor. There is little ash and slag after burning. It does not take up much space. Additionally, wood pellet ash is a high-quality organic potassium fertilizer that can be used on farms or in gardens.
Pellets are an efficient, environmentally friendly, and renewable energy source that can be used as an alternative to traditional fossil fuels. They have a high calorific value and efficiency, making them competitive in the heating and energy production sectors. While there are some drawbacks, such as the high initial cost of equipment and dependence on raw materials, the benefits of pellets far outweigh them. In the context of global climate change and the need to reduce harmful emissions, pellets can play a key role in the transition to a sustainable energy system.