Updated: July 2002
Activated Coke Moving Bed Filter1. Outline of the System
Dioxins removal can be achieved by the adsorption system from the flue gas exhausted from municipal solid waste or industrial waste incinerators. Activated coke can be applied to the system to adsorb dioxins and heavy metals keeping with higher removal efficiencies. The system can be adjusted to higher pollutants loading and/or fluctuated operation. The filter concept is simple and wide ranged adsorbents, such as conventional activated carbon, activated coke and special Aktinert adsorbent (inert material covered by powdered activated coke) can be applied. In Aktinert adsorbent application, coke consumption can be saved by recycling of the inert material mixing with fresh powdered coke after separation of the waste powdered activated coke around it.
2. Features
1) Highly efficient dioxins removal
Gaseous dioxins can be adsorbed on the adsorbent filled in the adsorption bed layers.
2) Heavy metals removal
Gaseous heavy metals, such as mercury and other gaseous micro pollutants can be removed by its adsorption capability.
3) Loading fluctuation
Dioxins can be separated efficiently by adsorption achieved with high buffer capacity of moving bed layers, if dioxins loading is fluctuated. In the moving bed layers being separated into three independent sections, dust can be removed efficiently. Thus adsorbent consumption can be minimized and stable operation can be realized without clogging or pressure loss increase.
4) Adsorption temperature
In Aktinert adsorbent (inert material covered by up to 3 mass-% powdered activated coke) application, the adsorbent can be taken as an inert material. Then the operation temperature can be designed at maximum 200ºC (normal 180ºC).
5) Waste adsorbent
Waste adsorbent can be recycled to the incinerator to destruct dioxins to avoid generation of the dioxins contaminated waste.
6) Compactness
By employing cross-flow type moving bed, the required space can be saved comparing to the conventional counter flow type moving bed.
7) Adsorbent consumption
The adsorbent consumption of Aktinert can be saved, because of higher utilization of its own adsorption capability comparing to the granular activated coke application.
Fig.1 Concept of cross-flow type moving bed filter
3. Performance
In the activated coke moving bed filter, operation temperature can be designed up to 200ºC to meet the temperature downstream bag filter or ESP.
Therefore, no special cooling or heating device will be required.
An example of performance on pollutants removal is:
1) Dioxins emission at outlet: < 0.05 [ng-TEQ/m3N]
(Maximum inlet loading : up to 100 [ng-TEQ/m3N])
2) Mercury emission at outlet: < 0.05 [mg/m3N]
3) Heavy metals (Pb, Zn etc.) emission at outlet: < 0.5 [mg/m3N]
4. Application Fields and Materials to be treated
1) Municipal solid waste incineration flue gas treatment
2) Industrial waste incineration flue gas treatment
3) RDF/Waste power generation flue gas treatment
4) Steel furnace flue gas treatment
5) Other micro pollutants flue gas treatment
Fig.2 An application of Activated Coke Moving Bed Filter (AKTINERT Adsorbent)
5. Other Information
The system is based on the licensed technology with Babcock Borsig Power Environment Gmbh (Germany) and more than 40 systems have been installed.
