Activated carbon from the bulk material container
The compact metering station developed by IB Verfahrens- und Anlagentechnik’s is already in use successfully in several waste incineration plants. The system’s receiver tank is equipped with metering screws according to the number of incineration lines. Each uses a frequency converter to continuously convey the required even metering quantity via a cellular wheel sluice to a pressure injector. The conveyance air generated by the side duct compactor draws the required quantity of activated carbon in and conveys this by thin stream conveying to the injection point in the flue gas duct.
Special features at a glance
- Storage silo with pneumatic filling
- Silo top-mounted filter for surge air
- Continuous fill level measurement
- Silo ventilation to support discharge
- Low-pressure injector sluices for thin stream conveying
- Metering from 1.5 to 15 kg/h per line (4)
- Rendering the storage silo inert
- Rendering the silo inert if
The receiver tank is supplied with activated carbon via small bulk materials containers that are placed on using a forklift or an optional electrical chain hoist. The discharge connects to the station automatically and dust-tight when it is placed on. After opening the discharge on the small bulk materials container, the very free-flowing activated carbon flows into the receiver tank. To prevent bridging and to ensure that the screw helix is filled evenly, the receiver tank is equipped with a loosening stirrer and a mobile suction cup beater. The stirrer runs intermittently during metering operation. The suction cup beater is used on both the container and the receiver tank in order to ensure that residues are emptied.
After each use, the activated carbon metering station should be run empty. As sulphur-contaminated activated carbon works against the 1.4301 material that comes into contact with the product, we recommend blowing the entire container filling (1800 litres) in and performing a “rinsing filling” that is run with standard activated carbon.
An emergency emptying process that may be required can be performed by opening the discharge slide on the station’s base. Attaching an optional vacuum hose enables the system’s receiver tank to be vacuumed almost empty using a suitable vacuuming vehicle.
The activated carbon metering station is equipped with an electrical switch cabinet. This contains all required electrical elements and the station’s controller. It is operated conveniently via an integrated “SIEMENS Touch-Panel”. There is the option to exchange signals with the control room. Each line can be operated separately and individually, i.e. the metering quantity can be adjusted within the defined range as required. All required operating messages and parameters are shown on the display. This includes the conveyance pressure, temperature monitoring in the product, fill level, metering quantity. The station is generally operated in “automatic mode”. Manual mode is possible under certain circumstances.
Due to the activated carbon’s properties and in accordance with an explosion protection report, the complete metering station including the small bulk materials container is designed to be explosion-protected in dust Ex zone 21. The injector range up to the injection point is defined for dust Ex zone 20 inside. Thanks to the station’s design and that of the components and materials used, all related requirements for use are met and confirmed by the assigned expert. TÜV acceptance has been performed.