Here is a small Collinson silo, UK manufactured, that I've modelled for a new map I'm working on. Relatively low poly-count (5000 tris). It can be imported to your map in GE without further edits if you only use 1. If more than one are placed, increment the save ID number in silo trigger attributes. This is not a placeable.
Capacity up to 32 tonnes (54.3 cubic metres).
Clearance height 4m.
Clearance width 3.6m