192
P. Weber et al.
Highlighted Equipment
For the WMG installation, Kuettner developed an off-gas treatment concept including
the final SBF post-combustion and boiler system with integration of Chinese thirdparty furnace technology.
Post-Combustion Transition Zone
To ensure full post-combustion of the process gas, so-called tertiary air is supplied to
the transition zone between the SBF and the waste heat boiler in controlled form. A
defined and controlled extra amount of tertiary air is added to control the temperature
of the combusted process gas. The injection of the tertiary air has been modelled and
designed to ensure proper mixing and temperature homogeneity of the process gas.
The waste gas generated in the reduction furnace contains a high content of dust,
mainly lead oxide. From the thermodynamic point of view, lead oxide will partly form
lead sulphate together with sulphur dioxide. This dust from the reduction furnace
tends to form sticky accretions at a certain temperature window. This can cause
harmful accretions on the boiler walls and heat exchanger tubes. The design of the
controlled tertiary air supply accounts for this temperature window and maintains
defined process gas temperature at the boiler inlet. This leads to a mitigation of the
accretion risk in the boiler.
The gas amount used as tertiary is comprised of process gases with some SO 2
content from suction points in the furnace area.
Waste Heat Boiler/Quench
It is necessary to cool down the process gas and the dust from the SBF furnace. This
is achieved in a waste heat boiler consisting of two radiation passes with integrated
water quench.
The flue gas passes through the first shaft going up and passes the second shaft
going down. At the top of the second shaft, the water quench is installed to cool down
the gas further. At the bottom of the second shaft, a dust box with screw conveyor is
installed to remove the dust that is separated in the second shaft.
Since the waste gas from the SBF will contain a certain amount of SO 2 , it is
necessary to account for the acid dew point of the gas. Therefore, the feed water
in the steam drum is preheated before it enters the first boiler pass. The boiler is
designed as a saturated steam boiler.
P. Weber et al.
Highlighted Equipment
For the WMG installation, Kuettner developed an off-gas treatment concept including
the final SBF post-combustion and boiler system with integration of Chinese thirdparty furnace technology.
Post-Combustion Transition Zone
To ensure full post-combustion of the process gas, so-called tertiary air is supplied to
the transition zone between the SBF and the waste heat boiler in controlled form. A
defined and controlled extra amount of tertiary air is added to control the temperature
of the combusted process gas. The injection of the tertiary air has been modelled and
designed to ensure proper mixing and temperature homogeneity of the process gas.
The waste gas generated in the reduction furnace contains a high content of dust,
mainly lead oxide. From the thermodynamic point of view, lead oxide will partly form
lead sulphate together with sulphur dioxide. This dust from the reduction furnace
tends to form sticky accretions at a certain temperature window. This can cause
harmful accretions on the boiler walls and heat exchanger tubes. The design of the
controlled tertiary air supply accounts for this temperature window and maintains
defined process gas temperature at the boiler inlet. This leads to a mitigation of the
accretion risk in the boiler.
The gas amount used as tertiary is comprised of process gases with some SO 2
content from suction points in the furnace area.
Waste Heat Boiler/Quench
It is necessary to cool down the process gas and the dust from the SBF furnace. This
is achieved in a waste heat boiler consisting of two radiation passes with integrated
water quench.
The flue gas passes through the first shaft going up and passes the second shaft
going down. At the top of the second shaft, the water quench is installed to cool down
the gas further. At the bottom of the second shaft, a dust box with screw conveyor is
installed to remove the dust that is separated in the second shaft.
Since the waste gas from the SBF will contain a certain amount of SO 2 , it is
necessary to account for the acid dew point of the gas. Therefore, the feed water
in the steam drum is preheated before it enters the first boiler pass. The boiler is
designed as a saturated steam boiler.