A pilot-scale study of selective desulfurization via urea addition in iron ore sintering

Abstract

The iron ore sintering process is the main source of SO₂ emissions in the iron and steel industry. In our previous research, we proposed a novel technology for reducing SO₂ emissions in the flue gas in the iron ore sintering process by adding urea at a given distance from the sintering grate bar. In this paper, a pilot-scale experiment was carried out in a commercial sintering plant. The results showed that, compared to the SO₂ concentration in flue gas without urea addition, the SO₂ concentration decreased substantially from 694.2 to 108.0 mg/m³ when 0.10wt% urea was added. NH₃ decomposed by urea reacted with SO₂ to produce (NH₄)₂SO₄, decreasing the SO₂ concentration in the flue gas.

Keywords

iron ore sintering / urea / flue gas / desulphurization

References

[1] Pan J., Zhu D.Q., Cui Y., Chen D., Zhou X.L. Emission rule of SO₂ in flue gas during sintering. J. Cent. South Univ. Sci. Technol., 2011, 42(6): 1495.

[2] Zhao C.L., Wu T., Bo X., Su Y. The status quo of sintering flue gas desulfurization of iron & steel industry and pollutants co-treatment suggestion. Environ. Eng., 2014 76.

[3] Zhang C.X., Wang H.F., Qi Y.H. Status of exhaust pollutant reduction in sintering process. Iron Steel, 2010, 45(12): 1.

[4] Dang Y.H., Wang H.F., Qi Y.H. Research on the flue gas desulfurization in sintering process. Iron Steel, 2010, 45(5): 88.

[5] Dang Y.H., Qi Y.H., Wang H.F. Technology of flue gas desulfurization. J. Iron Steel Res., 2010, 22(5): 1.

[6] Liu Z.J., Zhang J.L., Yang T.J. Research and development of sintering flue gas desulphurization technology. China Metall., 2009, 19(2): 1.

[7] Li G.H., Liu C., Rao M.J., Fan Z.Y., You Z.X., Zhang Y.B., Jiang T. Behavior of SO₂ in the process of flue gas circulation sintering (FGCS) for iron ores. ISIJ Int., 2014, 54(1): 37.

[8] Xiao J.J. Study on Online Desulfurization by the New Technology of Adding Urea in Sintering Process, 2014, Ma’anshan, Anhui University of Technology, 36.

[9] Long H.M., Chen X.L., Chun T.J., Meng Q.M., Wang P. Sulfur balance calculation of new desulfurization technology in the iron ore sintering process. Metall. Res. Technol., 2016, 113(1): 107.

[10] H.M. Long, X.J. Wu, T.J. Chun, J.X. Li, P. Wang, Q.M. Meng, Z.X. Di, and X.Y Zhang, Mechanism on selective desulphurization in iron ores sintering process by adding urea, High Temp. Mater. Process., DOI: 10.1515/htmp-2015-0172.

[11] Chen J.P., Isa K. Thermal decomposition of urea and urea derivatives by simultaneous TG/(DTA)/MS. J. Mass Spectrom. Soc. Jpn., 1998, 46(4): 299.

[12] Koebel M., Strutz E.O. Thermal and hydrolytic decomposition of urea for automotive selective catalytic reduction systems: thermochemical and practical aspects. Ind. Eng. Chem. Res., 2003, 42(10): 2093.

[13] Lü H.K., Yang W.J., Zhou J.H., Liu J.Z., Zhang M., Li F.R. Investigation on thermal decomposition characteristics of urea solution under high temperature. Proc. CSEE, 2010, 30(17): 35.

[14] Chen K.H. Generation mechanism of SO₂ in sintering process and its emission control. Sintering Pelletizing, 2007, 32(4): 13.

[15] Zhang Y., Chen W.S., Han J., Wu G.M., Tang J.F. Research on the distribution law of sintering flue gas NO_x. Ind. Saf. Environ. Prot., 2014, 40(4): 23.