China’s HBIS group has successfully started steel production through pellet flue gas ultra-low emission technology, which helps reduce pollutants such as pellet smoke particles, sulfur dioxide and nitrogen oxides to levels below national standards. The company claims it is the world’s first ultra-low emission pilot project for pellets.
Developed under the China’s 13th five-year plan, the pellet flue gas multi-pollutant ultra-low emission project achieved emission concentrations for pellet smoke particles of below 5mg/Nm³, sulfur dioxide less than 20mg/Nm³ and nitrogen oxides below 30mg/Nm.
The multi-pollutant control technology employs embedded SNCR along with cascade oxidation denitrification and SDA synergistic absorption pulse the pre-charge bag dust removal technology to reduce pollution.
Pellets, a green option
Increasing the proportion of pellets in the blast furnace charge is a new development in the industry. Pellets have become a green option as they produce a smaller amount of flue gas per ton and have a lower sulphur and nitrate emissions compared to sintered ore.
Many steel mills in China are developing high-proportion pellet blast furnace smelting technology and this multi-pollutant control technology could help them meet national emission standards through upgradation of existing control systems. HBIS has developed the technology in collaboration with the China’s Institute of Process Engineering, Sinosteel Tiancheng Environmental Protection company and North China Electric Power University.
A demonstration project of the multi-pollutant flue gas emission control was completed on 2mn mt annual capacity pellet line of HBIS’s Tangsteel Qinglong furnace. The project was completed in April. In the commissioning and trial stage, the system operated stably and achieved ultra-low emission targets.
China’s emission-control battle
China’s ultra-low emission standards are among the most stringent standards, globally. It requires NOx emissions to be stable below 50mg/m³. China is rigorously clamping down on steelmakers that are flouting emission standards and are not investing to upgrade their existing facilities to adopt ultra-low emissions.
Steel mills that conform to emission standards are allowed to operate during smog alerts while non-conforming mills have to reduce production or shut down lines as prescribed by provincial authorities.
In July, Henan province introduced a pilot project that imposed differentiated power and water tariff on polluting steelmakers. By the end of 2020, steel mills in the Capital Economic Zone or Beijing-Tianjin-Hebei, the Fenwei Plain and the Yangtze River Delta have to meet ultra-low emission standards. This region contributes to 60pc of China’s steel production capacity.