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.