In the iron & steel industry the Annular Gap Scrubber - invented by Bischoff - is used as gas cleaning equipment and simultaneously as flow or pressure control unit for complete processes.
Typical applications are blast furnaces and steelmaking plants.
Special features
- Axial-symmetric design
- Minimum space requirements
- Can be used as flow or pressure control device
- Excellent dust collection efficiency
- Non-clogging spray nozzles
Working Principle
How do Annular Gap Scrubbers work?
In general the annular gap scrubber consists of two stages. First the gases enter into the pre-scrubber stage which is passed with low velocity for efficient cooling and separation of coarse dust.
Several spray nozzles are installed inside the pre-scrubber and continuously spray water into the gas. The temperature of the gas decreases rapidly down to the saturation temperature.
The dirty waste water which is flowing down the scrubber shell is discharged ahead of the second scrub¬bing stage. The connection pipe to the RS-element is located in the lower part of the pre-scrubber.
In the second stage, the fine de-dusting takes places via the GEA BISCHOFF RS-elements with variable annular gap. The most important part of the RS-scrubber is a conical element, which is axially adjustable – driven by a hydraulic cylinder - and forms an annular gap together with the conical shell. One GEA BISCHOFF spray nozzle, arranged centrally and spraying unilaterally, is installed upstream of the RS-element.
This arrangement of the spray nozzle guarantees a regular water distribution over the annular gap cross section which is an important precondition for efficient gas cleaning.
Gas and water are forced through a zone of high turbulence having a corresponding intensive interaction leading to excellent dedusting efficiencies. Dirty waste water is discharged in the bottom section and the gas flows to the downstream demister where most of the remaining droplets are separated.
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