Thermal Oxidation with regenerative Heat Recovery (RTO)
for Lime Production

Posing the task

The customer operates a lime plant with several shaft kilns. Besides natural gas also solid fuels such as anthracite and coke are used to fire the kilns. This results in a TOC emissions result above the permitted level. The emissions for CO also exceed the limit of the German TA-Luft which will be mandatory in some years.

Solution / Highlights

To comply with the emission standards a RTO was installed. To protect the heat exchanger of the RTO, the existing fabric filter was upgraded with a continuously dust measurement device. Any excess of the accepted limit results in a pypass of the RTO.

The main difficulty in implementing the project lay in the very high concentration of carbon monoxide. CO gas has a low calorific value, but tends to the spontaneous reaction in the ceramic heat exchangers of a RTO. This results in problems in achieving the required clean gas values, and the consumption of additional fuel. Through a matching control concept called COntrol, the system can still be operated economic and regulatory compliant.