What is the calorific value of wood pellet related to?

Wood pellet is a new energy environmentally friendly fuel that has been vigorously developed in recent years. Wood pellet mainly uses biomass raw materials (such as sawdust, straw, rice husk, peanut husk and other agricultural and forestry wastes). Wood pellets are biomass fuel made by the pellet machine mainly used to replace coal to achieve smoke-free environmental protection, and can also be used to replace gas and electricity, which can achieve environmentally friendly emissions and reduce operating costs. More and more industrial users and commercial users choose biomass pellet fuel as energy products. When using wood pellets, the customer asked the most about the calorific value of wood pellets and whether it can meet production needs. In order to answer customers’ questions, we summarized the factors affecting the calorific value of wood pellets.

1. What is the calorific value of wood pellets related to? The raw material of the fuel determines the approximate range of the heating value of the wood pellets

The raw material determines the calorific value of wood pellets. Generally, there are many raw materials used to make wood pellets. It is precisely because the raw materials are abundant and renewable that it has the regeneration properties of biomass pellet fuel. At present, the raw materials that can be processed into wood pellets on the market mainly include sawdust, tree branches, bark, furniture factory scraps, wood flour, rice husk, cotton stalks, peanut shells, medicine residue, bamboo chips, sludge, construction templates, wooden pallets, corn stalks, etc. These raw materials can generally be processed into the following more common types of wood pellets: rice husk pellets (heat value 3000-3300Kcal/kg),peanut hull pellets (heat value 3500-3800Kcal/kg), straw pellets (calorific value 3000-3200Kcal/kg), mixed wood pellets (calorific value 3800-4000Kcal/kg),pine wood pellets (calorific value 41000-4500Kcal/kg).

Judging from the calorific value of several common wood pellets above, the calorific value of wood pellets is mainly determined by the raw materials. The calorific value of wood chips can reach about 4000Kcal/kg, and the lowest is the average calorific value of straw materials. It reaches about 3000Kcal/kg.

2. What is the calorific value of wood pellets related to? The moisture level of wood pellets has a slight effect on the calorific value of wood pellets

The calorific value of wood pellets is greatly affected by the raw material, so what factors affect the calorific value of the same raw material? Generally speaking, the amount of moisture makes the content of combustible substances in the wood pellets relatively decrease, and the calorific value decreases. In the biomass pellet combustion test report , there is generally a low calorific value and High calorific value, the so-called low calorific value means that the moisture in the monitored wood pellet sample is the normal value, while the high calorific value is the calorific value of the wood pellet sample after being burned, so the biomass pellet fuel Calorific value and moisture level have an impact. The high moisture content of wood pellet makes it difficult to catch fire, affects the burning speed and easily causes black smoke. Therefore, when purchasing various biomass pellet fuels, the moisture content of the biomass pellet fuel should be less than 10%.

Based on the above two points, it can be seen that there are still many factors affecting the calorific value of wood pellets. In fact, the density and ash content of biomass pellet fuel also affect the calorific value of wood pellets. Why does density affect the calorific value? When the material particles are burned, they need to release heat per unit volume. If the low-density wood pellets has a lighter weight per unit volume, and the high-density wood pellets has a heavier weight per unit volume, so the denser biomass fuel The calorific value of the material pellet fuel is naturally higher than that of the low-density biomass pellets. One cubic meter does not affect it. However, if the amount of biomass pellet fuel used is more, the impact of the calorific value can be seen. The influence of ash on the calorific value of biomass pellet fuel is not difficult to understand. 1% ash and 4% ash, biomass pellet fuel with 4% ash has a calorific value lower than 1% ash. The weight of the burned particles is small.