| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing high-purity urea water, in which the biuret concentration of the urea water can be reduced by using the inexpensively-produced urea and by an inexpensive method.SOLUTION: The method for producing high-purity urea water for a urea SCR system, which urea water is obtained by treating an urea water undiluted solution having 2,500 ppm or higher biuret concentration with activated carbon and has the reduced biuret concentration, comprises: a biuret adsorbing/removing step of treating the urea water undiluted solution of 100 ml with the activated carbon of 1.0-3.0 g; and a biuret desorbing/removing step of desorbing the biuret from the biuret-adsorbed activated carbon. At the moment that the biuret concentration exceeds a regulation value of 2,400 ppm when the biuret adsorbing/removing step is carried out, the biuret desorbing/removing step is carried out.SELECTED DRAWING: None |
