If you want a reliable flow for pet coke out of a silo then

I am afraid it is neither cheap nor easy. Best option is to

get your material tested for properties such as wall

friction angle, internal friction angle, time consolidation,

flow function etc. Then get a silo designed for mass

flow with the proper outlet size. Also make sure

the designer / manufacturer guarantees a mass flow

silo. It will be expensive but will save you loads of

headache in future. ■

There are a number of good publications for silo design.

Prof. Michael J. Rotters book on the 'The economic guide to the design of circular metal silos'. ISBN 0 419 23460 8 is good

starting point.

Hope it helps. ■