The article discusses techniques for making bio-coal briquettes from low-grade coal and agricultural residues. The researchers developed a method to reduce energy consumption and improve the quality of the briquettes by using filtration dryers for drying coal and biomass, and an organic binder made from woody biomass. They found that adjusting parameters like temperature and bed length can optimize the production process, resulting in bio-coal briquettes with good mechanical integrity and higher calorific value.