In the field of flue gas cleaning several proven techniques are well established. According to the forces of free enterprise economy and environmental requirements, the development of an economically reasonable procedure, based on well-known processes, which can also guarantee the fulfillment of legal emissions, was carried out. For the evaluation and scale-up criteria a pilot plant has been built, on which also the relations in the presented model have been verified. At the time, scrubbing of SO2, HCl and HF with Ca(OH)(2) below their emission limits according to legal limits for cleaned flue gas (Siebzehnte Verordnung zur Durchfuhrung des Bundes-Immissionsschutzgesetzes Verordnung uber Verbrennungsanlagen fur Abfalle und ahnliche brennbare Stoffe-17. BImSchV vom 23. November, 1990 (BGB1. I 2545, 2832), BRD) is realized. The process, and in consequence the model, which is basis of the discussion of this paper, is built in an open structure to permit rearrangements of and extensions to the process. This paper gives an introduction to the model, which is based on pilot plant data and theoretical reflections under consideration of scale-up criteria. This model has been developed to calculate demands of operating materials and basic dimensions of plants as well as to evaluate theoretical considerations on measurement data.