HYDRAZINE SYNTHESIS AS A METHOD OF PURIFICATION OF CARBAMIDE PRODUCTION EFFLUENTS

Abstract

Today, the search of promising directions of production improvement is an urgent task. In the process of carbamide synthesis, up to 1.5 m3 of wastewater per ton of product is formed. Steam condensate formed during the concentration of a carbamide solution in vacuum evaporators is the main part of the effluent. For purification, the effluent is sent to a hydrolyzer for the hydrolysis of carbamide. Next, a desorption of ammonia and carbon dioxide occurs. Sewage containing bound nitrogen compounds for further treatment are sent to biological treatment facilities. The effectiveness of biological purification does not exceed 80 %. The aforementioned method of wastewater treatment requires high costs of electric and thermal energy. Hydrolysis and desorption of juice condensate are estimated as the most modern and most promising way of waste disposal. This method is implemented in all plants for the synthesis of carbamide. The article considers a new method for the utilization of nitrogen-containing condensates of carbanide production by using them as secondary raw materials for hydrazine synthesis. A study of the synthesis of hydrazine in an electromagnetic synthesis reactor has been carried out. The effect of the flow rate of the reaction mixture entering the electromagnetic N2H4 synthesis reactor on the prod-uct yield has been studied. The dependence of the degree of conversion of total nitrogen to N2H4 on the flow rate of the reaction mixture into a multimode electromagnetic hydrazine synthesis reactor is established. Experimentally obtained data are mathematically processed in order to establish the optimal flow regime. The results of calculating the mathematical model of the kinetics of chemical reactions initiated by electromagnetic heating are confirmed by solving the system of Arrhenius equations and thermal conductivity in an implicit scheme. It has been confirmed that cyclic heating of the reaction mixture is more effective. In the course of studies, it is found that the synthesis of hydrazine proceeds in the diffusion area. Despite the fact that the absence of pumps reduces the energy consumption of a hydrazine synthesis plant from secondary raw materials, it is difficult to control the production process when introduced into production. The phenomenon of spontaneous regulation of the rate of removal of the synthesis solution from the reaction zone is initiated by the effects of internal airlift by CO2 gas and implosion.