Cleaned carbon monoxide (CO) gas can be used as secondary energy, which saves primary electric energy in ferroalloy production and also replaces other fossil fuels at adjacent works. Utilization of CO gas significantly lowers total dust and gaseous emissions and improves ferroalloy and steel works energy optimization.
Collecting the finest particles from electric furnace off gases is challenging with wet scrubbing methods, so we have developed a cassette-type filter that enables the efficient removal of even the smallest particles that pass through the scrubbers. As an option, our patented coke dust injection unit can be installed before the CO gas filter, with coke dust being used to absorb the tar from the CO gas. CO gas from the metallurgical process is blown into the filter and uniformly distributed between all the filter elements, and the dust is retained on the filter element surfaces.
The filter elements are cleaned with a nitrogen jet pulse cleaning system. The collected particles are flushed with water into the water lock tank from where the slurry is collected. Micro-filtered gas is very clean (solids content can be as low as < 1 mg/Nm³) and can be utilized in many different solutions, such as cogeneration.
Micro-filtering CO gas with Metso's Outotec CO gas filters significantly improves the environmental performance and energy efficiency of the smelting plant. Filters are becoming an integral part of electric furnace off-gas cleaning systems.