The molding principle and conditions of briquette machine
Briquette machine is the special equipment used for processing sawdust, straw, grass, wild weeds and other materials into briquettes by mechanical extrusion and compression in order to make the combustion value and time of per unit volume increased and prolonged by several times. The briquettes produced by briquette machine are mainly used in fireplace, gasification furnace, boiler and power plant. Straw briquettes after compression are also the ideal feed for horses, cattle, sheep, deer, ostrich and other ruminants.
The molding principle of briquette machine: There are large amounts of lignin and cellulose in the plant, while the lignin has no melting point but it has softening point. When the temperature reaches 120-160 degrees, the soluble substance in the lignin begins to melt, and the lignin will get soften and plasticized in 180 degrees, then they would stick closely with cellulose and fuse together with adjoining pellets under certain pressure.
The molding conditions of briquette machine: The molding of materials can be achieved with the principle that plants could soften under certain conditions . Different types, moisture content, volume and proportion of materials result in the uncertainty of forming conditions, uncertainty of briquetting technology and complexity of process. Some technical problems are still bothering people today. Therefore, master the briquetting technology is equivalent to master the whole technology for mechanism charcoal production.
1. The moisture content of raw materials:The moisture content of raw materials has great influence on the forming process and the quality of the products. When the moisture of raw material is higher, too much steam would be generated in the heating process and cannot be exhausted smoothly from the center holes of the briquettes, which would lead to surface cracking of briquettes or even no briquette can be produced. However, the molding of briquette is also very difficult when the moisture content is too low, since trace moisture plays a promoting role in the softening and plasticizing of lignin.
2. The molding temperature (theoretical temperature): molding temperature has great influence on the discharging speed, density, appearance and quality of briquettes. Therefore, the temperature should be adjusted properly according to certain materials to ensure the quantity and quality of the briquettes.The temperature that raw materials required has been introduced before. It’s important to note that if the temperature is too low to make the lignin softening, it will lead to the blockage of briquette machine, even the broken of screw if you are not careful enough. However, higher temperature would result in serious decomposition of raw materials and surface carbonization of briquettes. Thus, it is difficult to form the effective pressure for molding. Even if briquettes can be produced, the density of which can not up to standard. In the case of severe carbonization, a charring layer would forms in the inner wall of the cylinder, which will also lead to abnormal operation of briquette machine. Generally speaking, pine and hardwood have great adaptability to the temperature difference, especially the larch, which can be made into briquettes in higher or lower temperatures. While some raw materials have higher requirements on the temperature.
3. HeatingCurrently, stainless steel electric heating coil and computer electromagnetic heating system are used for heating with high heating speed and energy saving.