Kohlendioxidemissionen einer Sonderabfallverbrennungsanlage

Abstract

The Kyoto-Protocol defines global as well as individual binding goals for the reduction of so-called green-house-gas emissions. Trading of certificated emission rights is one of the instruments to achieve these goals. Within the EU, trading of certificated emission rights is regulated by the directive 2003/87/EU. In Germany, this directive was transferred into national legislation by release of the Treibhausgas-Emissionshandelsgesetz (TEHG) and additional laws and ordinances. At time, waste incineration plants are not subject of these regulations, but have to be considered as possible in the near future. Nevertheless, waste management has to be discussed in regard of its contribution to the greenhouse effect and in the context of the sustainable management of resources. In this situation the knowledge of the amount of so-called renewable materials in waste to be incinerated is essential: The incineration of renewable materials is regarded as 2 -neutral and certificated emission rights are not necessary. Since certificated emission rights are allocated on the basis of the total CO 2 emission, not required emission rights can be sold at the market. The amount of renewable material within municipal solid waste is in the range of 65 % -representing 50 - 60 % of the total carbon. Suitable information for hazardous waste is not available yet. To get a better idea about the situation regarding hazardous waste incineration, an investigation had been performed at the plant of the HIM GmbH in Biebesheim, Germany. This plant has two identical incineration lines for hazardous waste with a total capacity of about 16 t/h. Each line is equipped with a rotary kiln furnace, followed by a secondary combustion chamber and a boiler. The flue gas cleaning is performed by means of a spraydryer, an electrostatic filter, a four stage scrubber system and an entrained flow reactor system. In this investigation, carbon dioxide emissions have been measured and the waste input materials were monitored. For calculating a carbon balance the need of auxiliary chemicals in the flue gas cleaning system, the consumption of fuel oil and the emissions of other carbon containing substances had to be considered. In an additional experiment, the classification of the amount of renewable materials in hazardous waste was performed by measuring the fraction of 14 C in the emitted carbon dioxide. The data for the carbon mass balances were collected over a longer period. Calculated for a whole year of operation a total amount of 123.204 t hazardous waste had been incinerated and about 24.177 t of carbon was emitted as carbon dioxide. Since only about 230 t of carbon entered the system as fuel oil or additive, most of the carbon derived from waste material. Based on this balance the total amount of carbon in hazardous waste was calculated to be about 20 % (residual household waste: 20 - 30 %). On the basis of 14 C-measurement the amount of renewable carbon in the emitted carbon-dioxide was determined to be about 10 %. Taking into account the wider range of carbon in renewable organic matter - compared to plastics and other materials arising from fossil carbon sources - a fraction of up to 8 % of the waste input can be classified as renewable. The work carried out showed no possibilities for directly accessible reductions of carbon dioxide by optimization of plant operation, for example by reducing the consumption of fuel oil or carbon containing additive, which is used in the flue gas cleaning system.