Life cycle assessment of ultra-low treatment for steel industry sintering flue gas emissions

Lin Cui; Kaiming Ba; Fangqiu Li; Qingsong Wang; Qiao Ma; Xueliang Yuan; Ruimin Mu; Jinglan Hong; Jian Zuo

doi:10.1016/j.scitotenv.2020.138292

Life cycle assessment of ultra-low treatment for steel industry sintering flue gas emissions

Sci Total Environ. 2020 Jul 10:725:138292. doi: 10.1016/j.scitotenv.2020.138292. Epub 2020 Apr 2.

Authors

Lin Cui¹, Kaiming Ba¹, Fangqiu Li¹, Qingsong Wang¹, Qiao Ma¹, Xueliang Yuan², Ruimin Mu³, Jinglan Hong⁴, Jian Zuo⁵

Affiliations

¹ School of Energy and Power Engineering, Shandong University, Jinan 250061, China.
² School of Energy and Power Engineering, Shandong University, Jinan 250061, China. Electronic address: yuanxl@sdu.edu.cn.
³ School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250101, China.
⁴ School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
⁵ School of Architecture & Built Environment, The University of Adelaide, SA 5005, Australia.

PMID: 32298887
DOI: 10.1016/j.scitotenv.2020.138292

Abstract

The largest contributor to pollutant emissions is the sintering process in steel industry. Ultra-low emission policy for the Chinese steel industry states that emission concentrations of particulate matter, SO₂ and NO_x should not exceed 10, 35 and 50 mg/m³ respectively. The emission concentrations of the steel industry are the same as the ultra-low emission policy for the coal-fired power industry, but the pollutant control technologies of the two industries are different. Life cycle assessment method is applied to analyze the latest ultra-low treatment process for sintering flue gas emissions which includes electrostatic precipitation, ozone oxidation, wet desulfurization, wet denitration, condensation dehumidification and wet electrostatic precipitation. Following this novel ultra-low emission treatment, the concentrations of particulate matter, SO₂, NO_x, and PCDDs in the sintering flue gas decreased very significantly, attaining the new emission standard. With 1 ton of sinter as the functional unit and "cradle to gate" as the system boundary, the environmental impact of the process is 0.1811 and the total economic cost is 172.79 RMB, of which internal cost is 34.64 RMB and external cost is 138.15 RMB. The main environmental impacts result from applying the wet denitration and ozone oxidation processes. Sodium sulfite in the wet denitration process, and electricity and liquid oxygen in the ozone oxidation process are the key inputs that cause environmental impact. These findings are useful for a further optimization of the ultra-low emissions process from both the environmental and economic perspective, which is applicable in other regions of the world.

Keywords: Air pollutant; Life cycle assessment; Sintering flue gas; Ultra-low emission.