Achternbosch, M.; Richers, U.
Karlsruhe: Forschungszentrum Karlsruhe 2002
(Wissenschaftliche Berichte, FZKA 6726)
In the Federal Republic of Germany, thermal waste treatment is a major disposal path for the so-called "waste to be transferred to disposal" following the separation of reusable waste material. Up to now, large-scale plants are being operated at 53 different locations in Germany. In these plants, about 11 mio tons of waste are incinerated annually. This means that presently about one third of the total amount of waste arising is being disposed of by means of thermal waste treatment plants.
Due to legal regulations, in particular the Technische Anleitung Siedlungsabfall [TASi], thermal treatment will gain importance in the long term. As a consequence, new waste incineration plants will have to be built and old incineration plants replaced in order to maintain the disposal capacities in the Federal Republic of Germany.
When building a thermal waste treatment plant, two principal questions arise. First, the actual thermal treatment process has to be selected. In addition to conventional incineration on a grate, new processes were developed in the past years. The waste is pyrolyzed or gasified or pyrolysis or gasification is coupled with subsequent incineration. Furthermore, a flue gas cleaning system has to be designed for all thermal waste treatment processes.
Conception of the flue gas cleaning system is influenced by the thermal treatment method selected. Due to the large number of flue gas cleaning technologies available, very different flue gas cleaning systems may be installed for the different thermal treatment methods. Nearly all flue gas cleaning systems currently operating in Germany differ from each other.
In the past, there was a tendency to build increasingly complex and expensive flue gas cleaning systems for different reasons. This development started with the "17th Federal Emission Control Ordinance; Ordinance Regarding Incineration Plants for Waste and Similar Materials (17th BImSchV)", according to which a reduction of emissions was required. In addition, public and politics requested the actual emission values to be far below the legal limits.
This led to the construction of very extensive flue gas cleaning systems by the plant constructors. However, it should be kept in mind that extensive flue gas cleaning systems have a positive effect on the turnover and profits of the plant constructors.
In view of this situation, the question arises, how an ecologically and economically reasonable flue gas cleaning system should be designed when building a new plant. In general, it may be assumed that simple flue gas cleaning systems of low investment costs are characterized by a high need for operation agents and larger amounts of residues produced. Minimum amounts of residues usually require more sophisticated methods of flue gas cleaning, which lead to higher investment costs.
Comparisons based on a detailed analysis of the distribution of pollutants in the flue gas cleaning system, the materials flows resulting from the use of auxiliary chemicals, and the investment costs of the plants are still lacking.