Most Portland cement is made in a rotary kiln, which is a is a long cylinder rotating about its axis once every minute or two. As we see the photo below, the hot air in the burning area is supplied by turbo blower, as blower is big cost in cement plant, turbo blower to replace traditional roots blower save a great money.
We have turbo blower application for cement kiln in cement plant video link:
https://www.youtube.com/watch?v=YQbwVeCRtB8