Urea-Ammonium Sulfate Suspension Fertilizers: Bench-Scale and Pilot-Plant Studies. TVA Circular Z-141

摘要

Soils in many areas of the world are deficient in sulfur because of the increasing use of high-analysis, low-sulfur fertilizers and emphasis on pollution control. Therefore, TVA is developing a process for production of a 29-0-0-5S urea-ammonium sulfate suspension as one answer to this sulfur deficiency problem. The production equipment consists essentially of a boiling-type tank reactor and two coolers. Urea-water solution, sulfuric acid, ammonia, and water are feed materials. The reactor effluent is cooled to slightly above saturation temperature and suspending clay is added. Finally, the product is rapidly cooled further in a second-stage cooler to obtain an abundance of small crystals. Product concentration and cooling procedure are primary factors affecting product quality and the process. When pilot-plant studies are complete, TVA plans design and construction of a 25-ton-per hour (23 t/h) production unit. 4 figures, 5 tables. (ERA citation 08:010753)