Ring die of wood pellet mill
Ring die is important to the pellet mill as the heart to a man, ring die with good quality could guarantee higher yield per hour, power consumption and the quality of the pellet product. If you already have a pellet mill machine, you would know that the cost of ring die is a big part in the pellet production, also change ring die too frequently would influence the continuous production.
As a wood pellet mill manufacturer, here are the advices for you to choose the right ring die to fit into your pellet mill machine:
The first thing you should consider is the compression rate, which means the rate of hole length and the hole diameter. This factor is related to the raw material you choose, the fiber and lignin content micro-structure of the crushed biomass raw material.
The second is the metal quality: one popular iron type is 4Cr13, which the hardness value could reach to HRC50, after the heat processing.
The third is the finish degree of the ring die surface, the molding process would be affected a lot, sometimes raw material jam would happen and the pellet mill machine need to be shut down for maintain.
Surface crack of biomass pellet production
Allusion to the crack and transfiguration of biomass in the hot forming process at present, the research will analyze the factors and probe into the root causes of the cracks. Three achievenments are received which crack is related to rate of water content, charging rate and other factors; the shearing strength originated in the process of plasticity flow after material reached yield strength is the main cause resulted to craze; the function of keeping model canister to cut down crack mainly acts on the process of plasticity flow.
Feeding speed of the screw: the speed of the screw would affect the feeding speed and the length of the pellet product; also the friction between pellet and the die hole inner surface. Friction would make the pellet temperature rise, cracks are more easily to occur.
Shape retention tube: tests showed that pellets are less likely to have crack situation after staying in the shape retention tube, the working principle is to reduce the residue stresses, including the thermal stress, it is more like cold pressing and the effect is very obvious.
Life cycle analysis of wood pellet products
Wood pellet products are known as the possible supplementary for coal and fossil fuels, and the promotion has been put out for decades, while the words spread out as wood pellet has so many advantages compared with the traditional fuels, such as: environmental friendly, less CO2 emission, cheap, easier processing, less pollution, etc. Why so many years has passed, and no extraordinary progress has been achieved. Recently, the specialists has found the reason, and one conception was created-life cycle analysis, for wood pellet products, either as substitute or supplementary of coal, there must be pure energy created in the whole progress during the raw material forming, wood pellet production, using of wood pellet.
In the early wood pellet and other biomass briquetting studies, energy consumption and gas CO2 emission are usually the factors that people would focus on, the economic factors are usually neglected. As a single product, wood pellet must has all the characteristics that other products have, including the economical ones. After mass studies and research, the analysis model 3Es (Economics, Energy, Environment) was build up, it is going to help the development of wood pellet industry in the future.
