With nearly a decade of renewable energy experience, I worked with a Swiss pellet industry supplier, Bathan AG. My position needs to understand all aspects of the pellet factory, so I joined our service and maintenance team and did a lot of work. To improve my understanding of the inside of the factory - especially to observe its operation and how to keep the plant running smoothly. In this column and future versions, I plan to share with you the lessons I have learned at work.
There are two very talented and experienced engineers on my team who have more than 30 years of experience and they let me quickly master the technical aspects of the granulation plant and other equipment in the pellet plant.
As you know, the granulation process is conceptually simple: dry and ground sawdust is compressed at high pressures and temperatures to ensure adequate density. However, efficient and reliable operation of the granulator requires considerable skill and Experience, and sometimes requires a lot of improvisation. Therefore, the learning curve of the granulation business is long and steep, especially when you see the difference between a separate setting and a mixture of raw materials.
North America and Europe account for 67% of global particle production, so it's worth knowing about these two markets. I have found some differences from several visits to pellet plants in Europe and North America. In Europe, almost all pellet plants use starch. As a binder, most of the pellets are produced according to EN Plus standards for residential heating. In the United States and Canada, industrial pellets for export account for most of the market, with the largest share being industrial heating, such as the Drax Power Plant in the UK. Using hardwood and cork or a mixture of the two to produce granules, they need to be processed and peeled, but impurities are still unavoidable, so the wear on the equipment is much higher. Therefore, the cup and cone bearings in North America are very Popular, because they are serviceable compared to box bearings. In addition, there is a seat release space from the cup and cone system that allows more surface areas to contact the cup, allowing for more efficient dispersion Load. In addition to the settings, another major difference is that the temperature monitoring during operation usually does not exist, which makes the operator turn a blind eye to the condition of the roller, which increases the fire. The risk of disaster. This prompted us to develop an improved temperature monitoring system to track the temperature of each roller.
On two continents, the trend is to renovate internal drums to track quality and reduce maintenance costs. The best way to retread the rollers is to match the temperature to prevent assembly damage. The induction heater or oven can be used to heat the housing by gradually warming up. The ideal temperature for the body is about 260 degrees Fahrenheit (127 degrees Celsius), and the ideal temperature for the bearing is 155 degrees Fahrenheit (68 degrees Celsius). The bearing should slide easily into the housing. Using cup and tapered rollers, just replace the outer casing. Instead of disassembling the running bearing - the shaft assembly. The picture on the left is the roller after 1000 working hours - the bearing can be reused. The right figure shows the distribution of dirty grease in the retread roll - the initial damage is obvious.
Author: Holger Streetz
Bathan AG International Operations Manager
H.streetz@bathan.ch
