EFFECTIVE APPLICATION FOR REMOVAL OF DIOXINES FROM COMBUSTION PRODUCTS AND GASES
Processes and Technologies of a New Generation
Nowadays, the construction of new incinerating plants as well as the operation of the existing ones treating municipal waste and, in first place, dangerous waste is permitted only in case that the required purification of combustion products is provided for.
From the point of view of contamination of combustion products it is the presence of halogenated polyaromatic compounds having a high degree of toxicity to be extraordinarily dangerous. First of all, these are polychlorinated dibenzodioxines and dibenzofuranes marked with the abbreviation PCDD/F. There is a great number of PCDD/F types differing not only as for their composition but also as for their degree of toxicity. Their total amount is, therefore, determined as the toxic equivalent. In terms of EU it is the emission limit amounting to 0.1 ng/m3 of combustion products to be valid in relation to these substances.
The most used procedure of removal of PCDD/F from combustion products is the adsorption technology using carbonaceous sorbents – active coal.
In order to reach the residual amount of PCDD/F below the admissible limit of 0.1 ng/m3 the machine equipment must work under optimal process conditions, whereas there were used special types of carbonaceous sorbents with a high efficiency as well as capacity there.
Both these basic criteria are met thanks to a new technology developed and tested, as for its function, by the manufacturer of waste incinerating plants SMS CZ, s.r.o. Rokycany in cooperation with the manufacturer of sorbents of the series CHEZACARB® EKO Unipetrol RPA Litvinov.
This technology intensifies the purification process presenting, at the same time, the application of the latest knowledge as well as results of a research activity in the field in question. It also applies the knowledge of world technology of the latest period, including the information and knowledge of research workplaces in the Czech Republic.
Basic Features of this Innovation Technology Are:
- A technical innovation and a high variability as for the structural solution of units in dependence on local conditions of incinerating plants.
- A special type of sorbent, i.e.
CHEZACARB®EKO, having
the below-cited typical features:- A high specific surface, above 1000 m2/g, with a high capacity and efficiency as for the removal of PCDD/F and PCB.
- A high porosity, above 3.5 cm3/g, accelerating the transport of PCDD/F and PCB from combustion products to the active surface, where they are trapped.
- A small size of basic particles, i.e. approximately 20.10-6 mm, capable to group (agglomerate) around contaminating substances and to bond them irreversibly.
- A small size of particles enabling the creation of approximately 2 mill. particles in 1 m3 of combustion products creating, thus, a perfect homogenizing environment of sorbent in the whole volume resulting in a high efficiency and removal of PCDD/F and PCB within an extraordinarily short period.
- A surface with a fixed sure amount of colloidal sulphur enabling chemisorptive trapping of heavy metals.
- The content of a trace amount of oxidation catalyser.
This technology enables to meet both the Czech and the European limits relating to removal of contaminating components from combustion products with a sufficient reserve (approximately 50% or even more).