Thermal Treatment
© H.-G. Oed
Application of new measuring and analysis technologies for the reduction of contaminants and the recovery of residues from waste incineration
High-resolution combustion chamber spectroscopy has been tested in a pilot plant in order to clarify findings to the effect that NOx formation in waste incineration plants is influenced by combustion control and the geometry of the combustion chamber. This “ORFEUS” system has proven its value as a diagnostic tool for combustion chamber analysis.
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Basic investigations into the thickstock procedure using toxic chemical wastes, particularly filter ash from waste incineration plants, in salt rock
As a basis for the further development of the thickstock procedure, a wide range of investigative results have been collated and documented for the purposes of this project. Particular attention has been paid to the composition of filter ashes, and to the flow properties and stabilisation behaviour of suspensions of these ashes.
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The polluted sewage sludge is pre-sieved and then crushed in a planetary-gear extruder to enable trouble-free incineration in a stationary fluidized bed combustion system.
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Conversion of a great firing system to a low-NOx suspension firing system for clipbord scraps and the use of a woven filter
A tension boiler with nozzle plan rust and a water-tube boiler with three parallel under-thrust firing troughs were equipped with an injecting firing system and woven filters for dedusting. The fuel mixture from massif wood and melamin resin-coated chip boards is injected tangentially into the cylindrical combustion chamber (Brennermuffel) by means of a high-pressure ventilator and is burned out in the enlarged firing area. The primary air is supplied under-stoichiometrically to the cyclone combustion chamber, the secondary air to the combustion chamber. A flue gas feedback and the addition of hydrated lime serves for the reduction of the NOx - and HCl emissions. The dust emissions are at 10 mg/m³ (further information in German).
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A reduction of CO emissions to 100 mg/Nm³ with a TOC content of C <1% in the ash was achieved through constructive modifications to a pilot pulsed reactor. The focus of studies carried out to this end were shapes, sizes and positions of aero-valves, as well as the optimisation of the combustion chamber.
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Development, technical investigation and optimisation of residue-free cement production as an integrated process with the simultaneous recycling of various residues
Various wastes have been used as raw materials and fuels in a cement kiln installation by the use of a circulating fluidised bed system in combination with a calcinator. Product quality remains unchanged, emissions lie below statutory limit values and it has even been possible to reduce quantities of waste water.
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Ecological comparison of various residue treatment methods with the objective of inertization and recycling
Techniques for treatment of residues of municipal solid waste incineration are investigated as to their level of development and their expenditure/use-ratio with respect to technological, ecological and economical aspects. Mass- and energy-balances and emissions are evaluated for each process. With a market analysis of the intended applications for the treatment products, realistic estimations of the sales potential are derived.
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Emission reduction at refuse incineration plants: Improving combustion, burn-out and emission behaviour of a refuse incineration plant by optimation of the combustion process
The concept developed for combustion control in waste incineration plants can be used to offset variations in the composition and calorific value of fuel. This system allows the automatic adjustment of complex control parameters whilst ensuring compliance with all stipulated limiting values.
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Investigations into the long-term behaviour of chemically immobilised wastes and residues in underground cavities
Where residues from waste incineration plants are deposited underground, there will be a potential hazard associated with the soluble heavy metal content of these residues, which may be released by the ingress of geogenous water. Geogenous conditions and long-term variations in the chemical environment must therefore be taken into account in laboratory investigations.
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Modification and optimisation of a cement kiln with grate preheater for the combustion of PCB-contaminated waste oil
A 3,300 t/d cement rotary kiln with grate preheater was modified in order to be able to burn PCB-contaminated waste oil in the main firing of the rotary kiln under simultaneous thermic use of the waste oil at a flame temperature of up to 2000 C. The concentration of dioxines in the exhaust gas of the cement kiln was in general far below 0.1 ng/m³, which is a result of the high combustion temperature and the alkali conditions in the cement kiln. Significant changes in the quality of the product did not occur when using waste oil.
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