The ‘South-to-North Water Transfer’ in the conversion section”

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The water resources in our country are unevenly distributed between the north and the south; the North China Plain suffers from severe water shortages, while the Yangtze River basin has relatively abundant water resources. We know that a large-scale project to transfer water from the south to the north has already been implemented. In the contact process sulfuric acid conversion section, the heat distribution during primary and secondary conversion is also uneven; there is always an excess of heat available to heat the primary gas (coming from the SO2 drying tower), and a economizer or boiler is often required at the inlet of the absorption tower to remove this excess heat. However, the heat available to heat the secondary gas (from the intermediate absorption tower) is often insufficient, especially for acid production plants operating at low concentrations or with low load, such as those that produce acid from zinc smelting flue gases. It is evident that in most zinc smelting flue gas acid production plants in China, the inlet temperature of the subsequent beds is low, which affects the secondary conversion rate and the overall conversion rate. Another reason for the insufficient heat to heat the secondary gas is that the demister in the intermediate absorption tower (Tower 1) contains acid, which causes leakage in the heat and cold exchange tubes downstream; once these tubes become blocked, the heat transfer area decreases.