A high-efficiency top gas cleaning system is vital for reliable operation and long campaign life of gas and blast systems, energy recovery and steam generation facilities. It allows the plant operators to meet the relevant pollution control standards. Thanks to extensive expertise built up over decades, Paul Wurth is an environmental solution provider being able to supply technology, systems and equipment designed to the highest levels of cleaning efficiency, safety and reliability. With more than 140 worldwide references in BF top gas cleaning, Paul Wurth offers a proven design, plant and core components, as well as plant improvement.
The Axial Cyclone for high-efficiency dry dust separation with its compact design usually fits perfectly into an existing plant configuration. A wear-resistant lining provides for optimum system lifetime, whilst the dust removal efficiency (typically more than 85 %) of this dry technology is adjustable individually to suit the overall requirements.
The Annular Gap Scrubber with its movable Venturi elements provides high dust capture efficiency at minimum pressure loss and is the state-of-the-art in controlling blast furnace top pressure.
Since the cyclone solution takes away a high amount of coarse material from the gas stream, the comparatively small quantities of residual sludge extracted from the scrubber contains a high ration of lead and zinc. Paul Wurth’s propriety CIROVAL® technology will be used for separating this sludge into a Fe/C fraction and into a ZnO/Pb product, both to be recycled in different ways. Blast furnace sludge basins will become a picture of the past.
Prior to the use of blast furnace top gas’ calorific value in combustion processes, the use of the Top Gas Energy Recovery Turbine (TRT), an expansion turbine installed downstream of the gas cleaning equipment, can transform the potential energy of the top gas into electricity.
For a large blast furnace with high top pressure, the gas recovery results in substantial electric energy savings and contributes, in a sizeable way, to the reduction of carbon dioxide emissions. In certain cases, even a mechanical coupling of TRT to the same blast furnace’s blower station for cold blast generation is possible and results in best energy recovery performance.