Improve Smelter Sulfuric Acid Emissions

The development of the production technique of sulphuric acid is reviewed and desulfurization of the fume is introduced in this paper. In the mean time, the fundamental principle of acid making is elaborated on, its influencing factors are analyzed in detail and specific measures on how to improve its efficiency are put forward from the aspect of thermodynamics and dynamics.In view of the acid production status and the problems be faced with in Shaoguan Smelter, besides insuring the high-efficiency operation of tail gas treatment system and tapping the latent power, renovations and reformations should also be made toward the technology and equipments of the acid making system from the following aspects to improve the exhaust emission, save energy, reduce the consumption and improve productive capacity.(1) Improving the efficiency of electric precipitation and dust removal and purification of purification system.(2) Modifying the conversion, drying and absorption system and improving the effect of drying and absorption, the conversion rate of sulphur dioxide and production capacity.Considering the scarce capacity of purification equipments, the overage conversion equipments and technological characteristic of zinc and lead sintering process, we made the following modifications toward the acid making system in Shaoguan Smelter premised that the existing equipments could be utilized to reduce investment outlay.(1) Purification system: C-shaped plates with wide polar distance and constant current source with high voltage were adopted in electric precipitation. A stage of dynamic wave scrubber was added between the empty tower and washing tower. The washing tower was merged with the first and second stage of electrostatic demisters and the existing first and second stage graphite intermediate coolers were replaced by lead ones. The empty tower was reserved without any modification.(2) The conversion system: The double-conversion and double-absorption technology was adopted.After the modification, the acid making system has large adaptive capacity of technological fluctuation and self-heating balanced capacity with over 99.50 percent of overall conversion rate. The rate of the reach of the set standard of sulphur dioxide discharge of 120m chimney and acid mist was improved .The total amount of the dischargewas decreased considerably and the other indexes were improved to a greater or less extent. At the same time, after settling the technical problem, synchronization of starting up the sintering and the acid making process was realized, which improved the pollution at low-level atmosphere and the operation environment further.