Modelling of vertical roller mill and technical analysis
Axo, Cedric (2024)
2024
Julkaisu on tekijänoikeussäännösten alainen. Teosta voi lukea ja tulostaa henkilökohtaista käyttöä varten. Käyttö kaupallisiin tarkoituksiin on kielletty.
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi-fe2024082766538
https://urn.fi/URN:NBN:fi-fe2024082766538
Tiivistelmä
There is a growing need to reduce energy consumption, in mineral processing, and to improve the efficiency of operations. To improve the mineral processing, it is crucial to understand the breakage mechanisms in different equipment and how it impacts the product. The processing of minerals requires multiple equipment, depending on the desired characteristics for the product. The energy required for processing the material is relevant, but it is also important to minimize the stream of by-products.
The objective of the thesis was to analyze a vertical roller mill (VRM) and to use the information to improve the performance of a VRM. Most common crushers and mills were analyzed to understand what other equipment is used when minerals are processed. The VRM is efficient, quiet and produces a uniform product. In the theoretical analysis, parameters that impact the performance of the VRM were listed in two tables. The parameters can be used to modify the performance of the VRM. By modifying the performance, it is possible to adapt the mill to a changing demand.
In the experimental part of the thesis, a mill was analyzed and optimized. The mill faced some challenges that had to be addressed. Fundamental problems were found in the process and recommendations were made to improve the performance. In addition, the mill had issues producing some products, because of excessive vibrations. The vibrations have caused downtime due to excessive wear. By analyzing the mill, it was concluded that the vibrations were caused of a stick-slip effect. The stick-slip effect can be caused of an excessive roller pressure. The vibrations were minimized by decreasing the roller pressure, which improved the performance of the mill and all products could be produced normally.
Besides improving the performance of the mill, it was decided to model the grinding in the VRM. By modeling the grinding it was possible to estimate how the product changes if the raw material is modified. Dolomite is processed in the factory, which is extracted locally. From the dolomite processing a by-product is produced. There was an interest to use the by-product in the process, which would decrease waste. From the results of the model, the product did not change significantly when the by-product was added. By using the by-product the benefits would be; less waste, more efficient extraction and decreased raw material costs.
The objective of the thesis was to analyze a vertical roller mill (VRM) and to use the information to improve the performance of a VRM. Most common crushers and mills were analyzed to understand what other equipment is used when minerals are processed. The VRM is efficient, quiet and produces a uniform product. In the theoretical analysis, parameters that impact the performance of the VRM were listed in two tables. The parameters can be used to modify the performance of the VRM. By modifying the performance, it is possible to adapt the mill to a changing demand.
In the experimental part of the thesis, a mill was analyzed and optimized. The mill faced some challenges that had to be addressed. Fundamental problems were found in the process and recommendations were made to improve the performance. In addition, the mill had issues producing some products, because of excessive vibrations. The vibrations have caused downtime due to excessive wear. By analyzing the mill, it was concluded that the vibrations were caused of a stick-slip effect. The stick-slip effect can be caused of an excessive roller pressure. The vibrations were minimized by decreasing the roller pressure, which improved the performance of the mill and all products could be produced normally.
Besides improving the performance of the mill, it was decided to model the grinding in the VRM. By modeling the grinding it was possible to estimate how the product changes if the raw material is modified. Dolomite is processed in the factory, which is extracted locally. From the dolomite processing a by-product is produced. There was an interest to use the by-product in the process, which would decrease waste. From the results of the model, the product did not change significantly when the by-product was added. By using the by-product the benefits would be; less waste, more efficient extraction and decreased raw material costs.