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Objective
Mercury is
often released from thermal treatment plants during short
periods of time creating very high mercury peak concentrations
in the raw gas. Many traditional flue gas treatment systems
have limited buffer capacity and they cannot reduce
these peak concentrations as much as required. In such
case, or in applications where the raw gas mercury levels
generellay are high, the MercOx process offers a very
efficient alternative or complementary separation
system for mercury removal.
The MercOx mercury removal process is especially competitive in
applications with a high proportion of metallic mercury in the
flue gas, since this form is not separated at all in a normal
acid scrubber. Examples of such applications are:
- Sludge incineration
- Smelting works
- Incineration of hazardous waste
- Thermal soil decontamination
- Industrial processes
The process
can also be combined with ADIOX® -tower packing
material for dioxin removal and/or energy recovery through
flue gas condensation.
Client
benefits
- Allows higher mercury (Hg) content in fuel
- Offers system cost optimisation thanks to the fact that
there are several functions in one unit (also for example
integrated SO2 and HCl removal)
- Efficient at concentration peaks thanks to the large
buffer capacity
- Environmental friendly oxidant
- Low residue handling cost thanks to the small amount of
residue product.
- High reliability
- Cost competitive.
General
concept of MercOx mercury removal
The MercOx process is a flue gas cleaning
method for the purpose of separating mercury from the flue
gas. In this process the metallic mercury, which is insoluble
in water, is oxidised to water-soluble forms. In the same
cleaning stage, hydrochloric acid and sulphur dioxide are also
separated.
During the incineration of material
containing mercury, the mercury is released almost completely
into the flue gases. The composition and temperature changes
in the flue gases influence the final division of the mercury
into metallic (water-insoluble) and oxidised (water-soluble)
forms. Traditional wet flue gas cleaning methods only separate
the water-soluble form. It is therefore often necessary to
supplement the mercury removal process with an activated carbon filter or a
MercOx-unit.
The MercOx mercury removal process has been
developed by Götaverken Miljö and Forschungszentrum Karlsruhe,
which is a leading research institute in the field of mercury,
dioxins and aerosols. The process utilises the
environment-friendly oxidising agent hydrogen peroxide,
together with an additive, to oxidise the metallic mercury. This means that the MercOx mercury removal process can separate different forms of mercury. Sulphur
dioxide is also oxidised to sulphuric acid, and hydrochloric
acid will be disolved in the scrubber liquid. An acid water
flow containing mercury is transferred from the scrubber to
the water cleaning process for neutralisation and
precipitation of mercury.
Products
The MercOx mercury removal process is offered
separately or as part of a larger gas cleaning installation,
as a "package unit" scrubber supply or on a licence basis when
existing scrubber systems are easily modified.
Dimensioning
The process is designed for each
specific case on the basis of the flue gas parameters with
expected mercury concentrations.
References
Read more about the
MercOx process in our reference
brochures.
Reference example:
Flue gas cleaning with mercury and dioxin reduction - SAKAB, Sweden (1,1 MB)
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