| Abstract: | Environmental requirements world wide and in the P.R.of China in particular have increased and authorities are increasing the pressure on steelmakers to comply with always more stringent limits and standards. Modern converter steel making goes along with the innovation and new developments not only for the primary converter process itself but even more for the dedusting technologies.This paper describes the benefits and latest development of advanced off gas cleaning and recovery systems based on dry type cleaning with electrostatic precipitation and wet type gas cleaning based on wet scrubbers.Modern converter dedusting is based on suppressed combustion systems in order to reduce off gas amounts and to be able to use the gas for gas recovery.The dry type primary off gas treatment system based on electrostatic precipitator technology is the most advanced environmental solution available for converter steel making.Dry dedusting has been introduced in China successfully with a significant contribution by Siemens VAI being the market leader for converter dry dedusting systems.Siemens VAI has introduced several design improvements over the last years such as CFD modeling of flow conditions in evaporation cooler,design of chains for dust conveyors,design of ESP inlet,design and thickness of discharge electrodes and operation in energy saving mode.Additionally the DDS process has been successfully implemented in China for the De-P process.The gas recovery system for DDS has been optimized over the years with high quality equipment and integrated automation and control systems.Wet type dedusting for converter gas is a well proven technology for many years and is still widely used due to the simplicity of the process and the lower investment costs.SVAI has continuously improved it’s wet dedusting technologies to provide highly energy efficient systems which can achieve lowest levels of clean gas dust while still maintaining a moderate water and energy consumption with simplified process control and standardized process control packages.Main design and process improvements include expansion joints for connection of scrubber to cooling stack,new type of droplet separator,advanced hood pressure control package,ID fan washing system,ID fan speed control system etc.The focus for wet type gas recovery systems is still on maximum safety and reliability.SVAI has also successfully improved the technological packages for converter gas recovery for wet type dedusting systems.The comparison between the two system shows the advantages of dry dedusting mainly being the lowest clean gas dust content, lower operating costs,easier handling for recycling of residuals and no need for a water treatment plants.Wet type dedusting has it’s main advantages in the simple process and operation of the system,the flexible layout solutions inside the steel shop as well as generally lower investment costs.An overview on the numerous reference installations for dry- and wet type dedusting systems in China as well as world wide is given. |
