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factors influence your briquettes burning

By Jack Huang    Jan 07, 2014

Energy briquettes are a sustainable fuel made by biomass briquettes presses from biomass materials such as saw dusts, wood shavings, straws, rice husks, wasted border, abandoned furniture, etc. Biomass briquettes have different sizes and shapes which are decided by the requirements of the combustion chamber and the biomass briquettes presses. Briquettes are used to replace fossil fuels by households and industries for they are green , environment friendly and sustainable and easy to be handled. The burning effect of briquettes are the concerns of briquettes consumers.

Benifits of burning biomass briquettes
Benifits of burning biomass briquettes


As a biomass fuel, there are factors that influence the briquettes burning, such as, briquette calorific value, briquette density, briquette resistance to humidity and air flow, ash removal, positioning of briquettes in burning equipment, etc.

Briquettes quality

Briquettes quality is one of the most significant factors influence the burning of briquettes. Briquette calorific value density and resistance to humidity are the influencing briquetting burning directly.

Calorific value

Calorific value of briquettes are one of the most influential factors to briquette burning. Higher the calorific value is, the easier and better they will be burned. For your reference, the calorific value of some of biomass are presented in the following forms:


Briquette density influences the briquetting burning. High density briquettes tends to have a longer burning time and release more heat. Briquette density is significantly affected by raw material particle size and moisture content. The smaller the particle size is, the higher the density of the briquettes is. Moisture content also influences the density. Water in feedstock will obstacle the briquette compression and water evaporator formed because of the high temperature will voids and decrease apparent density.

Resistance to humidity

Briquettes are going to be damaged when subjected to humidity because lignin and majority of binders added are water soluble. Water vapor, released from inherent moisture of briquettes during combustion creates a saturated climate at high temperatures, which is more fundamental to a briquette’s humidity resistance. During combustion if the briquettes crumble too quickly, the loose particles will elutriate unburned through the boiler or will block the airflow.

Factors influence briquettes quality

Briquettes quality influences the burning of briquettes significantly. Do you know what influence briquettes quality during briquettes productions? The quality of the briquettes is directly affected by physical parameters in briquetting process, such as pressing temperatures, compacting pressure, and moisture content.

Pressing temperature

Pressing temperature influences briquette quality and strength significantly. Pressing temperature impact the soften and excretion of lignin which will function as natural binders to join the fibers of the feed stocks to form solid high density briquettes. The interaction between pressing temperature and briquettes strength are shown in the following table.

briquttes pressing temperature and briquettes strength

The optimal pressing temperature is at the curve peak where maximum strength is achieved by briquettes. When the temperature is lower, briquettes are unstable, have less strength and are likely to crumble during burning, having shorter burning time and producing less heat eventually. When the temperature is higher, the volatile compounds may be burned out and cause burning during pressing.

Compacting pressure

Briquettes strength is increased with the increasing compacting pressure within the compacting limit of the feed stock. When the pressure is increased, the atmospheric humidity in the feed stock is decreased and briquettes durability is increased.

briqutte compacting pressure and briquetty quality

Moisture content

Moisture content is mainly affected by the feed stock species and its properties. The optimal moisture content is around 10 – 18 %. When the moisture content is lower than 10% or higher than 18 %, particles of feed stock are not consistent and briquette is tended to fall into pieces.

material humidity and briquette quality

In order to provide you a better understanding, the following video present you how the briquettes are made by commercial  briquette making machine, hoping it is useful for you.


All in all briquettes quality is one of the most significant factors influence the burning of briquettes. Briquette calorific value density and resistance to humidity are the influencing briquetting burning directly. In order to produce high quality briquettes, the processing variables, such as pressing temperatures, compacting pressure, and moisture content should be focused.

External factors influence briquettes burning

Besides the factors mentioned above, there are other factors that affect the burning of briquettes. They’re air flow, ash removal and positioning of the briquettes in the stove.


Airflow is one of the most important factors. Good airflow means good oxygen supply which is a must condition for burning. Only when the adequate supplying of airflow is grantees, the burning of the briquettes can be kept in a higher combustion rate, which means the optimal fire is possible and also prevents the happening of the smoky fire which is caused by insufficient airflow.

What influences your briquette buring

Briquettes burning

Ash removal

The ash produced by burning briquettes may cause problems. The reason is the ash may block the air holes and eventually lowers the oxygen supplying in the combustion chamber. That’s why ash content is one of the criteria that decide the quality of briquettes. And it’s important to choose high quality briquettes with low ash content. (When you’re planning to use self made briquettes, it’s better to do some research on the ash content of the raw materials and choose the biomass briquette presses with high compression power.) Even if high quality briquettes are used in the stoves, it is necessary to clean the ash from time to time to ensure the air hole is efficient to supply oxygen needed for combustion.

briquettes ash after burning in stove
Briquettes ashes  after buring in a stove

Briquettes positioning

The positioning of briquettes may influences the air flow and eventually influences the burning characteristics. Generally, the main purpose of positioning briquettes is to put them in a position enjoying good air flow. When position the briquettes, it’s better to intentionally leave a path for the air flow which make the oxygen available for the briquettes. Take the doughnut shaped briquettes for example. The briquettes should be put in an upright position, which makes the air easily go through the inner hole, enlarges the contact surface of the air and briquettes, and improves the burning efficiency.

screw briquettes buring
Screw briquettes burning