Catalytic for Chemical Manufacture

Sulfuric acid, which is used primarly in the manufacture of phosphate fertilizers, is produced in greater volume than any other industrial chemical. Sulfuric acid is made by first burning sulfur to produce SO2, reacting the SO2 over a catalyst to produce SO3, and then absorbing the SO3 into water to produce the acid. Conversion in the catalytic process is limited by equilibrium ¿ if the process can be operated at a lower temperature, the conversion of SO2 to SO3 could be increased. TDA has developed a novel low temperature catalyst for the oxidation of sulfur dioxide for sulfuric acid manufacture. This project will demonstrate the effectiveness of a new catalyst operates at temperatures 50-80°C lower than commercial catalysts, thereby providing greater per-pass conversion of sulfur dioxide to sulfur trioxide. Phase I synthesized and tested a series of catalysts and compared their activity with several commercially available catalysts. The new catalyst significantly outperformed the commercial catalysts at the lower temperatures and was stable in a preliminary lifetime test. An economic analysis indicated that the slightly increased cost of the new catalyst would be more than offset by its benefits. In Phase II, the catalyst will be further improved by examining both the composition and preparation method. In order to ensure good catalyst lifetime, an automated test system, which can run unattended for weeks at a time, will be designed and built. Test data will first be used to provide feedback to the catalyst optimiztion task, and then to test the catalyst¿s durability. Finally, we will determine the cost of manufacturing the catalyst followed by an economic analysis of using the catalyst for sulfuric acid manufacturing. Commercial Applications and Other Benefits as described by the awardee: A low temperature sulfur dioxide oxidation catalyst should substantially lower energy use in sulfuric acid manufacture while increasing throughput and lowering sulfur emissions. Increasing the conversion rate would reduce the amount of feedstock used, increase the energy efficiency of the sulfuric acid plant, and significantly lower sulfur emissions.