A sulfuric-acid process with near-zero SO2 gas emissions

A sulfuric-acid process has been developed that is able to handle low and variable SO₂ concentrations with practically zero SO₂ emissions (less than 3 ppm). The plant comprises two stages—a single-bed converter contact plant and a modified tower plant. Acids of 95–98% and/or oleum with up to 32% free SO₃ can be produced in the first stage. Off-gas of the first stage is piped to the second stage, where the SO₂ is converted to near nontracability while producing 76% strong acid. It is then returned to the contact plant to produce stronger acid or oleum. This process does not generate any additional disposable waste. For more information, contact T. Keilpart, Process Engineering Associates, 707 Redway Lane, Houston, Texas, 77062; (281) 488-6633; fax (281) 488-2456; e-mail PEA@net1.net.