The difference of hardwood and softwood pellets

Wood pellets can be classified into hardwood pellets and softwood pellets.

Hardwood is a category of wood that includes birch, poplar, yew, and elm, among others. Hardwood is characterized by its high density and low water content, which results in longer burning times compared to softwood.

Softwood refers to the category of wood that includes gymnosperms like pine, mahogany, cedar, and spruce. Softwood pellets generally burn more efficiently and thoroughly compared to hardwood pellets.

Wood pellets have versatile applications and can be used in various heating systems, barbecues, industrial boilers, and power generation. The burning efficiency of wood pellets is typically over 80%, which is higher than that of coal, which typically has an efficiency of around 60%. In addition, wood pellets produce lower levels of SO2, NOx, ash, and dust compared to coal.

Comparison between hardwood and softwood pellets

Price

Due to its higher cost compared to softwood, hardwood pellets are generally priced higher than softwood pellets. Hardwood pellets are often marketed and sold as superior pellets due to their desirable characteristics.

Heat value

Softwood pellets generally have a higher calorific value compared to hardwood pellets, typically resulting in 10%-20% more BTU heat generation. This is because softwood pellets tend to contain more sap than hardwood, which causes them to burn at a faster rate.

Ash content

The ash content of wood pellets depends more on the cleanliness of the sawdust than the type of wood. While high-quality wood pellets generally have low ash content (below 1%), hardwood pellets can generate about three times the amount of ash compared to softwood pellets. This disparity becomes more apparent during the winter period when wood pellets are used for heating.

Dust emission

In a 2009 research study comparing hardwood and softwood pellets, it was found that their burning ratios were similar, but their dust emission varied significantly. Softwood pellets had higher dust emission compared to hardwood pellets for materials with lower burning ratios. However, for materials with higher burning ratios, hardwood pellets had more dust emission than softwood pellets.

Advantages of wood pellets over wood logs

• Sawdust is readily available and considerably cheaper compared to wood logs.
• The process of making wood pellets involves crushing, drying, and mixing, which improves heat efficiency and reduces ash and smoke emissions.
• Wood pellets typically have a moisture content of less than 10%, whereas wood logs contain around 40-50% moisture. Higher moisture content in wood logs can decrease heat efficiency and increase smoke and ash emissions.
• A ton of wood pellet fuel burns for a longer duration compared to a ton of wood logs, and it also generates more heat.
• Wood pellets have the advantages of uniform size, shape, and density, making them convenient to store and transport. They are also well-suited for use in automatic burning systems.

Should I choose hardwood or softwood pellets?

There are a few factors to consider when choosing between hardwood pellets and softwood pellets.

Firstly, your fuel budget plays a role, as hardwood pellets generally cost more than softwood pellets. If you are looking to save on fuel expenses, softwood pellets may be a more cost-effective option.

Secondly, consider the compatibility of the pellets with your burning stove. Most wood pellet stoves can accommodate both hardwood and softwood pellets. Therefore, it is more relevant to compare the quality and efficiency of the stove rather than focusing solely on the type of wood used.

Lastly, the production process of wood pellets also influences their quality. Regardless of whether they are made from hardwood or softwood, the quality of wood pellets depends on factors such as raw material crushing, drying, molding, and cooling. Maintaining the appropriate size of raw materials (3-5mm) and moisture content (between 14% and 20%) is crucial. Therefore, it is important to consider how the pellets are produced rather than solely focusing on the type of wood used.