400
O. Petzoldt et al.: Removal of Mercury from Gases by Modified Zeolites in a Stationary Bed
mercury is recovered in elemental form during regeneration of the zeolite and
can be recycled. The regenerated zeolite is reimpregnated and similarly
reutilized.
The zeolite can be regenerated and estimated four to six times before needing
to be finally discarded, when it can be disposed of, for instance, by incineration
or depositing in a controlled or secure dump. Definite figures on the number of
reuses are not yet available.
6
Summary
Compared with other adsorption methods which mainly employ carbonaceous
adsorbents, the main advantage of the Medisorbon process lies in the safety
potential of the zeolite it uses. This means that it does not require the safety
devices, fire-extinguishing facilities, extensive instrumentation and so on
normally prescribed with other processes. There is no danger of spontaneous
ignition.
Owing to the hydrophobic nature of the ~eolite and its catalytic inactivity,
soaking and corrosion problems caused by formation of sulphuric acid do not
have to be contended with. These selective characteristics are naturally a
drawback when other substances such as S02, HCI, HF or other mercury
compounds like ionogenic form (HgH) need to be removed as well. In these
instances, additional process stages must be provided in the gas treatment plant,
for instance customary wet scrubber systems.
The Medisorbon plant is practically free from need for maintenance and
supervision. Removal, regeneration and refilling of the adsorbent is only
necessary at intervals of a few years.
Relatively high cost of the adsorbent compared with carbonaceous materials
can be offset by savings in running costs, long run time and useful life of the
adsorbent, absence of regular maintenance procedures, and lower first cost of the
equipment.
Naturally, it will be necessary to make proper comparison of all costs to
determine whether the Medisorbon process is the most economical alternative
for any actual project.
References
Daza L, Mendirioz S, Pajares JA (1993) Mercury elimination from gaseous streams. In: Applied
catalysis B: Environmental, 2. Elsevier, Amsterdam, pp 277-287
Henning KD, Keldenich K, Knoblauch K, Degel J (1988) Impregnated activated carbon for mercury
removal. Gas Sep Purif 2:20-22
Yan TS (1994) A novel process for Hg removal from gases. Ind Eng Chern Res 33:3010-3014
O. Petzoldt et al.: Removal of Mercury from Gases by Modified Zeolites in a Stationary Bed
mercury is recovered in elemental form during regeneration of the zeolite and
can be recycled. The regenerated zeolite is reimpregnated and similarly
reutilized.
The zeolite can be regenerated and estimated four to six times before needing
to be finally discarded, when it can be disposed of, for instance, by incineration
or depositing in a controlled or secure dump. Definite figures on the number of
reuses are not yet available.
6
Summary
Compared with other adsorption methods which mainly employ carbonaceous
adsorbents, the main advantage of the Medisorbon process lies in the safety
potential of the zeolite it uses. This means that it does not require the safety
devices, fire-extinguishing facilities, extensive instrumentation and so on
normally prescribed with other processes. There is no danger of spontaneous
ignition.
Owing to the hydrophobic nature of the ~eolite and its catalytic inactivity,
soaking and corrosion problems caused by formation of sulphuric acid do not
have to be contended with. These selective characteristics are naturally a
drawback when other substances such as S02, HCI, HF or other mercury
compounds like ionogenic form (HgH) need to be removed as well. In these
instances, additional process stages must be provided in the gas treatment plant,
for instance customary wet scrubber systems.
The Medisorbon plant is practically free from need for maintenance and
supervision. Removal, regeneration and refilling of the adsorbent is only
necessary at intervals of a few years.
Relatively high cost of the adsorbent compared with carbonaceous materials
can be offset by savings in running costs, long run time and useful life of the
adsorbent, absence of regular maintenance procedures, and lower first cost of the
equipment.
Naturally, it will be necessary to make proper comparison of all costs to
determine whether the Medisorbon process is the most economical alternative
for any actual project.
References
Daza L, Mendirioz S, Pajares JA (1993) Mercury elimination from gaseous streams. In: Applied
catalysis B: Environmental, 2. Elsevier, Amsterdam, pp 277-287
Henning KD, Keldenich K, Knoblauch K, Degel J (1988) Impregnated activated carbon for mercury
removal. Gas Sep Purif 2:20-22
Yan TS (1994) A novel process for Hg removal from gases. Ind Eng Chern Res 33:3010-3014