Energy- and Resourse-Saving Technologies and Equipment in Urea Production

Abstract

The milestones in the development of the urea industry in Russia are briefly outlined in commemoration of the 150th anniversary of the Bazarov reaction. It is noted that due to the unique consumer properties of urea, the demand for it and the volume of production increases from year to year. Significant volumes of production and high unit capacities of urea production reactors require the use of energy- and resource-saving technologies, the implementation of which in industry necessitates the creation of new high-performance equipment. The R&D work on such equipment was carried out in several directions. (1) Development of internal devices for high-pressure urea synthesis reactors (cross-sectional and longitudinal sectioning, feed components mixers). The developed internal devices increase the efficiency of the synthesis and the degree of conversion of raw materials into the final product, as well as reduce the recycle to the synthesis reactor. This allows not only improvement of the energy efficiency of the production (reducing steam, power, and circulating water consumption), but also creates prerequisites for increasing the productivity of the reactor. (2) Application of film-type heat and mass exchangers for melt stripping and evaporation of urea solutions. (3) Design of plate-type heat and mass exchangers. The construction of a film-type evaporation equipment of special design allows much more efficient heat and mass exchange compared to “submerged” equipment. In addition, the radically shorter residence time of the urea solution in such apparatus favors a lower amount of the biuret by-product. The use of the plate-type equipment with mass-exchange plates of special design reduces metal consumption, increases the efficiency of all processes, and reduces drop entrainment from the distillation column.