Graymont (qc) Inc.

Graymont (pa) Inc.

Alain Charette

Merrill Squire

A process and system for recovering waste heat from a kiln used for lime or cement production. The system unifies the kiln, a waste heat recovery and power generation circuit and a dry scrubber for scrubbing the pollutants from the kiln offgas. Essentially, the system employs the boiler component of the waste heat recovery and power generation circuit as a heat exchanger to recover the waste heat from the kiln, which is used to drive the steam turbines. The heat absorption from the latter stage lowers the temperature of the kiln offgas sufficiently for optimum performance from the scrubber. The presence of lime particles in the offgas effectively protects the boiler tube surfaces from corrosion which would occur at optimum scrubber temperatures, and subsequently provides the lime required as a scrubbing medium for the dry scrubber. Further, the efficient scrubbing allows for the use of any fuel for firing the kiln inclusive of high sulphur content compounds. A process for effecting the technology is also provided.

Integrated lime kiln process

A method of scrubbing a gas stream with re-circulated kiln dust when the kiln dust is hydrated to form a sorbent. The sorbent is re-circulated with un-reacted flue gas stream for scrubbing.

Growing community of inventors

Joliette, Canada

Alain Charette