The innovative development path of China's biomass pellet machine technology and the development of biomass energy industry are basically parallel and echoed, along with the state's policy drive for biomass energy and people's understanding of biomass energy all the way. In this process, the biomass pellet machine constantly tries to study various technical routes, including the evolution from feed machine technology, learning from foreign counterparts, and independent research.
China's biomass pellet machine technology development roads are tortuous, rapid development and product maturity are mainly concentrated in the past 10 years. At present, the technical route of domestic biomass pellet machine is basically clear, the core technology of the whole machine product is relatively mature; the reliability of key parts such as ring die and roller is greatly improved; advanced processing technology, heat treatment process and new materials are introduced in the industry and application.
According to the arrangement of pelletmill ring die, structural difference, power source of pelletmill and working mode, the classification and biomass pellet machine are divided as follows.
2.1 The mainstream product technology route is divided into vertical pelletmill and horizontal pelletmill according to different layout modes of ring die.
The working principle of the biomass pellet machine is to use straw, wood chips, rice husk and other raw materials in the high temperature and high pressure environment of the pelleting chamber through the action of extrusion and friction generated during the movement of the ring die and the roller (or ring die). The die holes are compacted and extruded to form a regular, densely shaped fuel.
Ring die and roller are the core components of the equipment. The mainstream technology mainly adopts single ring die + double roller (three pressure roller). According to the arrangement of ring die and material feeding relative to the whole machine, it is divided into vertical and horizontal type. The vertical pelletmill powder material is fed into the pelleting chamber from the upper part of the machine, the ring die is horizontally placed relative to the pelleting unit, and the horizontal pelletmill powder material is fed vertically from the front end of the pelleting chamber (by means of The fan power is forced to feed), and the ring die and the pelleting unit are arranged vertically.
The working principle of the horizontal pellet machine and the vertical pellet machine are basically the same, but there are advantages and disadvantages in the aspect of the machine's moisture content adaptability, maintenance convenience, cavity temperature, material transport and feed uniformity.
The horizontal pelletmill technology evolved from the feed pellet machine. The temperature in the pelleting chamber is relatively high. The failure rate of the working parts such as bearings is relatively high. The material transportation requires forced completion of the fan, and there is a problem of uneven material. The horizontal pellet machine also has the advantage of relatively high adaptability to the moisture content of raw materials. Generally, it can adapt to normal granulation of 20%-15% of raw materials, and the maintenance of key components such as ring die and roller is convenient. The pelleting chamber outer cover makes it easy to replace the ring die and adjust or replace the roller.
The vertical pelletmill technology is an innovative and improved product of biomass pellet machine. The powdery material enters the pelleting chamber vertically and uniformly from the upper part, the pelleting effect is relatively good, the ring die and the pressure roller wear evenly, and the service life is relatively extended. At the same time, the temperature inside the chamber is relatively low, and the failure rate of working parts such as bearings is low. At the same time, it also has a relatively strict disadvantage to the adaptability of raw material moisture content. Generally, about 15% of raw materials are required for pelleting, and the maintenance and maintenance of key components such as ring dies and rollers are inconvenient and long.