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A cleaner world

Wiser offers a range of tailored solutions for treating water, flue gases, and dust. Its technologies, many of which are internationally patented, are maintenance-free and highly reliable and energy-efficient.

Wiser-designed wet scrubbers are capable of eliminating virtually all particulates, metals, and hazardous substances from flue gas flows. As units operate on a closed water cycle, using intermediate Wiser-designed flotation purification, a system does not need constant fresh water to keep running. They also use less energy than alternative dry systems.

The process begins with a double-flow cyclone to separate out solid particles, after which the flue gas is rapidly cooled and washed, capturing any remaining particulates. The wet scrubbing stage also removes hazardous components, such as HCI, SO2, NH3, HF, and NOx, which are dissolved in the water, as well as metal solids, ash, and carbon black. Wet scrubbing is followed by fan-based secondary scrubbing, making use of the Venturi effect, and a two-phase drop separator.

Depending on the size of the plant and the amount of flue gas to be treated, multiple cyclones and fans can be installed, to cover a wide range of boiler loads and ensure that combustion quality and separation efficiency remain at the desired level.

The dissolved acid compounds in the scrubbing water are neutralised using either caustic soda or limestone, while a Wiser flotation unit removes metals and chemical compounds and other solids

A Wiser scrubbing system requires little sophisticated control technology, and even less manual input. Process water treatment, neutralisation, aeration, and flotation are all automatic. Energy consumption is minimal too, at around 1-1.3 kWh/1,000 m3 of treated flue gas. The process recovers the bulk of a boiler’s power loss in the form of heat, further enhancing its environmental ‘footprint’.

Simple and reliable

Wiser’s dissolved air flotation system differs from conventional systems in three key areas. The first of these is that dispersion water is produced without the use of air compressors or pressure tanks; the second is that it features non-clogging, self-cleaning flotation nozzles; and the third is that it uses mixing tubes to guarantee contact between microbubbles and flocs.

This makes a Wiser system particularly efficient for treating oily wastewater, reducing humus in intake water, or for improving the recovery of raw material from liquid flows.

Wiser dissolved air flotation systems offer the same inherent simplicity and reliability that Wiser’s wet scrubbing systems do, and installations at a number of plants have a proven track record with a minimum maintenance requirement.

Thanks to its small space needs, Wiser technology can be retrofitted to existing sedimentation basins to create a hybrid flotation system, eliminating the need for new basins or additional tertiary equipment, and offering very low running costs.

A Wiser wet scrubber system offers very high separation efficiency and excellent heat recovery. The heat from the flue gas transferred to the water in a Wiser system can be used for district heating purposes or to heat the site itself.
> Erkki Lindeberg
(Published in HighTech Finland 2008)