Abstract: A method of closed-loop control of a catalytic operation to clean offgas from a plant for processing of a raw material may involve determining an offgas composition downstream of a catalyst and varying an entrance temperature of the offgas entering the catalyst based on the determined composition. By varying the entrance temperature, the offgas composition downstream of the catalyst may be brought or maintained within a target range. A plant for performing such methods may include a processing apparatus for a raw material that produces an offgas, a catalyst, a measuring apparatus for determining a composition of the offgas downstream of the catalyst, a temperature-affecting apparatus for varying the entrance temperature of the offgas entering the catalyst, and a closed-loop control apparatus that actuates the temperature-affecting apparatus based on the composition of the offgas downstream of the catalyst.

Abstract: A plant may include an offgas-producing treatment apparatus for mechanical and/or thermal treatment of an inorganic material, an oxidation catalyst downstream of the offgas-producing treatment apparatus in a flow direction of the offgas, a reduction catalyst downstream of the oxidation catalyst in the flow direction of the offgas, and a temperature-affecting apparatus for affecting the temperature of the offgas upstream of the oxidation catalyst and/or between the oxidation catalyst and the reduction catalyst. In some examples, the the temperature-affecting apparatus is controllable and may comprise at least one of an auxiliary preheater, a mixing-in device for a fluid, or a heat exchanger.

Abstract: Methods for the heat treatment of a material flow and the cleaning of resulting exhaust gases are disclosed. The material flow may be preheated in a preheating zone, burned in a sintering zone, and cooled in a cooling zone. Exhaust gases of the sintering zone may flow through a preheater and be used for preheating the material flow. The exhaust gases leaving the preheater may be cooled at least partially in a comminuting device in interconnected operation or at least partially in a cooling device in direct operation. Exhaust gases may then be at least partly dedusted in a dust filter. A temperature of the dedusted exhaust gas may then be raised before the exhaust gas is cleaned of pollutants in at least one catalyst. A temperature at which the exhaust gases flow through the catalyst in direct operation may be higher, at least in phases, than a temperature at which the exhaust gases flow through the catalyst in interconnected operation.

Abstract: A method for cleaning bypass gases of the cement or mineral industry includes cooling down a removed bypass gas from a cement or mineral processing plant to a temperature of between 500° C. and 150° C., and coarsely dedusting the bypass gas, the dust burden being reduced by 30 to 95%. After the dedusting step, the gaseous constituents contained in the partly dedusted bypass gas are reduced in a reducing step. The partly dedusted bypass gas is further finely dedusted. The gaseous constituents reducing step includes at least a catalytic reduction of one or more of nitrogen oxides, hydrocarbons, and carbon monoxide.

Abstract: Improved methods and systems for purifying exhaust gases using regenerative post-combustion systems help reduce operating problems and increase service life of such regenerative post-combustion systems. One such method may involve preheating an exhaust gas to be purified before feeding the exhaust gas into a regenerative post-combustion system. The exhaust gas may be preheated in at least one preheating stage to temperatures between 100° C. and 250° C., for instance, preferably between 100° C. and 200° C., and most preferably between 120° C. and 150° C. Moreover, one regenerative post-combustion system may include a preheating stage, two heat stores, and an oxidation zone disposed between the heat stores for oxidizing harmful constituents present in the exhaust gas.