Chemical and other production processes release a wide variety of contaminated residues such as:
- exhaust air and off gases
- effluents and waste solvents
- sludge and solid waste
Three factors are important for good oxidation:
- suitable temperature
- sufficient dwell time
- and turbulent flow
The CTU systems, due to exceptional turbulence of the combustion gases, attain very high decomposition rates which even suffice to destroy flame retardants reliably.
Optimum energy efficiency can be achieved through:
- Internal, endothermic oxidation, in which exhaust fumes are preheated by exposure to flue gas heat to reduce auxiliary fuel requirements.
- External, exothermic oxidation, in which the energy from residues and combustion products is transferred to a heat transfer medium such as Steam, for external applications.
The type of oxidation is usually selected on the basis of the kind of pollutant so that the operational safety is not compromised through residue deposits or corrosion.
The type and the chemical reactions of the pollutants within the oxidation process often determine the complexity of the process and of the plant design:
- Nitrogenous residues may emit substantial quantities of nitrous oxide. The formation of nitrous oxide will be minimized by intelligent combustion control and then must be further reduced to permissible levels by SNCR or SCR technology in the flue gas treatment system.
- Residues containing halogenated compounds are difficult to disintegrate and result in corrosive components which are difficult to remove. They demand an appropriate flue gas cleaning process to ensure the emission to be below lawful limit.
- Inorganic materials, such as heavy metals, may result in the contamination of the ashes; further flue gas treatment must assure very low emission concentrations by appropriate process stages.
CTU has comprehensive know-how related to flue gas cleaning systems. Oxidation, heat recovery and flue gas cleaning are optimally sequenced and emission limits are maintained very low in order to guarantee best performance.
CTU technologies for oxidation of waste have a high reputation in the industry thanks to the number of successful reference plants in operation. At CTU, technical concepts are tailored as per customer's need. CTU combines high efficiency through minimization of pollutant emission with highest possible material and energy recovery and minimum use of consumables.
More than 25 of our plants for hazardous waste treatment are in operation worldwide.