Installation of a Brown Field Slag Reduction Furnace: State …
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Water from the steam drum is fed through the downpipe to the evaporator in the
walls of the boiler where it is evaporated partly, cooling the flue gases. The steam–
water mixture generated thus is led through the riser back to the steam drum. Due to
differences in density (water in downpipe/steam–water mixture in the riser), a natural
circulation arises in the cooling circuit.
The generated steam is collected in the steam drum situated on top of the boiler
passes. The steam drum is provided with a blow downpipe for partly dewatering in
order to reduce the salt content in the feed water.
Off-Gas Treatment
To reduce the dust load in the exhaust gas in a first process step, a cyclone separator
designed by Kuettner is installed behind the boiler. The separated dust is removed
with water-cooled screw conveyor.
Downstream of the cyclone, further waste gas cooling takes place to maintain
the desired filter inlet temperature of approx. 140 °C. It consists of a cooler where
SO 2 containing fugitive gases are injected into the gas stream. This cooler has been
modelled and designed to ensure proper mixing and temperature homogeneity of the
process gas.
As an additional benefit, in this cooler, process gas from existing TSL operations
is injected. This, along with the new filter, leads to a decrease of the overall site
emissions by the new installation.
Slag Granulation
The wet slag granulation was designed by Kuettner to ensure safe and reliable treatment of hot liquid slag from the SBF furnace. The granulation itself is executed in
the granulation box, where hot liquid slag flows from the top into a defined water
stream. Upon contact with the water stream, the slag is dispersed into small particles
while being rapidly solidified and cooled. The water/granulate mixture is led through
the granulation runner from the granulation box to the granulation basin, where the
granulate settles at the bottom. The slag granulate is taken out of the basin by an
automated crane grab, which serves the whole basin incrementally according to a
grid pattern.
The water in the granulation basin flows via an overflow to the so-called hot-water
basin. From here, the water is pumped to a cooling tower to reduce the temperature.
The cooled-down water from the cooling tower flows to the so-called cold water
basin, from where the water is pumped back to the granulation box.
193
Water from the steam drum is fed through the downpipe to the evaporator in the
walls of the boiler where it is evaporated partly, cooling the flue gases. The steam–
water mixture generated thus is led through the riser back to the steam drum. Due to
differences in density (water in downpipe/steam–water mixture in the riser), a natural
circulation arises in the cooling circuit.
The generated steam is collected in the steam drum situated on top of the boiler
passes. The steam drum is provided with a blow downpipe for partly dewatering in
order to reduce the salt content in the feed water.
Off-Gas Treatment
To reduce the dust load in the exhaust gas in a first process step, a cyclone separator
designed by Kuettner is installed behind the boiler. The separated dust is removed
with water-cooled screw conveyor.
Downstream of the cyclone, further waste gas cooling takes place to maintain
the desired filter inlet temperature of approx. 140 °C. It consists of a cooler where
SO 2 containing fugitive gases are injected into the gas stream. This cooler has been
modelled and designed to ensure proper mixing and temperature homogeneity of the
process gas.
As an additional benefit, in this cooler, process gas from existing TSL operations
is injected. This, along with the new filter, leads to a decrease of the overall site
emissions by the new installation.
Slag Granulation
The wet slag granulation was designed by Kuettner to ensure safe and reliable treatment of hot liquid slag from the SBF furnace. The granulation itself is executed in
the granulation box, where hot liquid slag flows from the top into a defined water
stream. Upon contact with the water stream, the slag is dispersed into small particles
while being rapidly solidified and cooled. The water/granulate mixture is led through
the granulation runner from the granulation box to the granulation basin, where the
granulate settles at the bottom. The slag granulate is taken out of the basin by an
automated crane grab, which serves the whole basin incrementally according to a
grid pattern.
The water in the granulation basin flows via an overflow to the so-called hot-water
basin. From here, the water is pumped to a cooling tower to reduce the temperature.
The cooled-down water from the cooling tower flows to the so-called cold water
basin, from where the water is pumped back to the granulation box.