Chemical Binding of Sulfur Dioxide in a Bubbling Reactor with the Use of Urea

Abstract

Introduction. Integration of Ukraine into the European Union requires a significant reduction in pollutant emissions from industrial enterprises. Special attention is paid to the entry of suspended solid particles, nitrogen oxides, carbon dioxide and sulfur dioxide from thermal power plants into the atmosphere.
Problem Statement. Sulfur dioxide is one of the main pollutants of the environment. Its entry into the atmospheric air leads to the formation of acid rain, which negatively affects people, soil, plants, and ground structures.
Purpose. To study the influence of the initial mass content of urea in an aqueous solution and its temperature on the efficiency of the process of chemical binding of sulfur dioxide.
Material and Methods. Several scholarly research publications dealing with the removal of sulfur oxides from waste gases of thermal power plants by various methods and technologies with the use of urea have been considered. The research is based on a mathematical model of a bubbling type chemical reactor.
Results. A series of numerical experiments on a chemical reactor where urea is used as a source of ammonia to bind sulfur dioxide in solution has been conducted. The calculations have made it possible to determine the optimal temperature of the solution at a certain urea content. The temperature should be equal to approximately 57 °C, at an initial urea content of 1%, 40 °C, at a content of 5%, and 35 °C, at 10%. Under such conditions, the efficiency of the process of chemical binding of sulfur dioxide in the solution is close to 100%.
Conclusions. The analysis of the results of mathematical modeling of processes in a chemical reactor has shown that for the pair of parameters “temperature-urea content” there are values at which the efficiency of the binding process reaches almost 100%. To control the efficiency, it is advisable to use the potential of hydrogen of the solution at a level of 7 ± 0.5. The lower values of the potential of hydrogen indicate a drop in the process efficiency, while the higher values indicate an increase in the concentration of ammonia in the treated gases at the reactor outlet.