Traditional VRM Feeding System
Grinding is one of the critical processes in cement production. Vertical roller mills (VRM) nowadays play an important part thanks to higher efficiency and more power saving performance compared to traditional ball mills. According to the design, the inlet and outlet of VRM are both in the upper part of the equipment. After the raw meals or clinkers are ground, they would be induced out by high negative pressure through the outlet. Due to this design, an issue has harassed many cement plants: how to prevent air leakage when raw meals or clinkers are delivered to the VRM.
This photo demonstrate how big the air leakage could be in traditional rotary feeder system.
Issues of traditional VRM feeding
According to the statistics and calculation, given ordinary operation level, 1% reduction in the oxygen content in waste gas will enable the system to save 0.7kwh/ton (clinker). Assuming the daily clinker production is 5800 tpd, and the monthly utilization
rate of the production line is 90%, based on the electric power cost at USD 0.08/unit, this 1% oxygen content reduction will contribute to an energy saving as below:
5800 tpd*90%*30days*USD0.08/unit=USD 12528.
How to tackle these problems?
How to reduce the oxygen content to a reasonable level?
Please wait for our next article for more information.