On dioxin removal and air pollution.

Technology review

Filtration+Separation July /August 2 0 0 6

Air pollution:

Wet, semi-wet or dry Adiox absorber technology targets

dioxin removal.

The Swedish municipal power company

material, resulting in multifunctional scrubber

at a municipal waste incinerator for more

Tekniska Verken Linköping AB has

systems where a dioxin absorption capability is

than a year. The gas is typically reheated to

contracted Götaverken Miljö AB to outfit

added to the acids removal and heavy metal

some 20 °c above the saturation temperature,

three of its municipal waste incinerators with

removal.

resulting in temperatures ranging from

a common dry Adiox absorber for dioxin

60 to 90 °c.

Even more functions can be added to the

removal. The maximum total flue gas flow is

scrubber by implementing MercOx technology

The dry Adiox application can be regarded as an

186 000 Nm3/h.

for the removal of elemental mercury, as well as

alternative - or complement - to the wet

The order is a breakthrough for Götaverken

enhanced energy recovery by flue gas

application, depending on the specific

Miljö and its Adiox technology; to date it has

condensation.

circumstances. The dry mode presents several

been installed in wet scrubbers at 50

advantages compared to the wet mode where

Adiox can be applied in scrubbers to minimise

dioxin removal alone is required, such as:

municipal and hazardous waste incinerators.

the so called memory effect, or to increase the

• More efficient dioxin removal per installed

The absorber to be installed in Linköping ( see

overall dioxin removal, which results in the

volume of packing;

figure 1 ) has a diameter of nearly 7 metres and

additional security of guaranteeing low emissions

a total height of 15 metres. The contract was

(in this respect, the memory effect is the well-

• A large volume can be installed in a single

signed at the end of June 2006 and the plant

known absorption/desorption of dioxin from

absorber section;

will be operational by end of 2006.

traditional plastic materials, which may

• No requirement for process water

sometimes cause problems regarding the dioxin

circulation systems;

Hooww ddooeess iitt wwoorrkk?? H

emission limits).

• Minimum requirements for electrical and

The Adiox technology is based on a special

Adiox can also serve as the main dioxin removal

instrument installations;

carbon doped plastic material, which can

technology of a flue gas treatment system, if

efficiently absorb large quantities of

• Low requirement for regular access and

installed in this way.

dioxins (PCDD/Fs). Wet scrubber interiors

maintenance, since the system is

such as tower packings ( see figure 2 ) and

An example of such an installation has been in

completely static;

droplet separators are fabricated in Adiox

operation at Måbjergværket (Denmark) for

• As a consequence of the above - very high

nearly two years ( See Filtration + Separation

availability;

December 2005, page 22 ).

• As a consequence of the above -

When the Adiox material needs to be replaced,

economically it is very competitive.

•

the used packing can be incinerated so that the

dioxins are destroyed. The system is thus a

Coonnttaaccttss::

Sven Andersson;

dioxin sink.

Per Lindgren (corresponding author):

Götaverken Miljö AB

Addiiooxx ffaaccttss

E: per.lindgren@gmab.se,

Adiox is marketed and sold by Götaverken Miljö

Web: www.gmab.se

AB as material deliveries, package units or turn

key flue gas treatment systems. To date, Adiox

has been used for wet scrubber applications in

several European countries - including

Germany, France, the Netherlands, Denmark

and Sweden, as well as in North America.

The operational modes of Adiox include wet,

semi-wet or dry mode:

• The use in wet scrubbers has been described

above;

• In semi-wet mode, saturated gas passes

through the Adiox tower packings without

continuous liquid circulation;

• In dry mode, the gas is first heated to above

the saturation temperature. Adiox was first

tested in the dry mode during the initial

development of the material. More

Figure 1: CAD model of Adiox dry absorber for

dioxin removal, to be installed in Linköping (Sweden)

importantly, it has also been in operation in a

Figure 2: Adiox Hiflow tower packings with high

by the end of 2006.

pilot plant downstream of the wet scrubbers

dioxin absorption capability.