Coffee grounds are the residue produced after brewing coffee. More than 2 billion cups of coffee are consumed worldwide every day, and most of the coffee grounds are discarded as garbage. The decomposition of coffee grounds releases methane into the atmosphere, exacerbating the burden of global warming. In fact, coffee grounds can be processed to produce high-value solid fuels for boilers and industrial heating, contributing to the circular economy. Fresh coffee grounds have a high moisture content, are prone to mold growth, and have a low calorific value. They need to be dried in a coffee grounds dryer first. After drying, coffee grounds can be used to make solid fuels, which are currently commonly divided into three types: biomass pellets, biomass briquettes, and charcoal.

Introduction to coffee grounds dryer

Drying is a key pre step in converting coffee grounds into efficient solid fuel. The most commonly used industrial dryer for coffee grounds drying is a rotary dryer, which can quickly reduce the moisture content of coffee grounds from 50-60% to 12-15%. The solid fuel produced under this moisture content has good quality, high calorific value, and will not cause adhesion or equipment blockage. The coffee grounds dryer uses fuels such as steam, coal, diesel, and natural gas for heating, it has high efficiency and controllable temperature, ensuring even heating of coffee grounds.

Working principle：Coffee grounds dryer adopts the downstream heating method. The coffee grounds enter the barrel from the feeding device and are pushed backward by the spiral flight board. Due to the inclined placement of the dryer, on the one hand, the material flows to the rear end under the action of gravity and rotation; on the other hand, the material is repeatedly picked up by the lifting board, brought to the upper end and then continuously sprinkled down, so that the material forms a uniform curtain in the cylinder, to fully exchange heat with the hot air in the cylinder. With the material repeatedly scattered, the moisture contained in it is gradually dried, so as to achieve the purpose of drying.

The utilization direction of solid fuel made from coffee grounds

After being dried by a coffee grounds dryer, coffee grounds can be directly used as fuel, but when made into biomass pellets, biomass briquette, and charcoal, the fuel performance is better. This not only provides combustion efficiency, increases calorific value, reduces smoke, but also makes transportation and storage more convenient.

1. Biomass pellets

After drying, the coffee grounds are crushed to a particle size of less than 5mm, and then sent to a biomass pellet machine for mechanical extrusion to compress them into solid particles with a diameter of 6-8mm. After cooling and screening, they are packaged. Coffee grounds pellets have high calorific value, smooth surface and good quality, which can replace fossil fuels as renewable fuels and reduce CO₂ emissions.

2. Biomass briquettes

The biomass briquette making machine is the key equipment for making coffee grounds briquettes. It uses a spiral extrusion process to compress dried coffee grounds into blocks, the briquettes have high density, small volume, and good combustion performance. They can be used as alternative fuels for wood and coal. The outer diameter of the pressure block is 50-70 mm, the aperture is 15-20 mm, and the shape is a square prism. The mold can be replaced with circular, square, hexagonal and other shapes.

3. Charcoal

At present, there are mainly two types of carbonization furnaces used to turn coffee grounds into charcoal - batch carbonization furnaces and continuous carbonization furnaces. They can be selected according to the actual processing capacity. Batch carbonization furnaces are used to process 3-10 tons of raw materials per batch, while continuous carbonization furnaces can process 1-10 tons of raw materials per hour. Carbonized coffee grounds can be further extruded into shape through a charcoal powder briquette machine.

Coffee grounds pellets, coffee grounds briquettes, and coffee grounds charcoal are three different fuel forms of coffee grounds. Currently, there are mature processes and markets for these three production lines, and the market prospects are promising.

Conclusion

Drying coffee grounds for fuel not only reduces environmental risks, but also promotes the transformation of energy structure. We have mature coffee grounds fuel technology and equipment. If you are interested in coffee grounds treatment solutions, please feel free to contact us at any time.