Modification of a Urea Production Unit by Using Computational Fluid Dynamics Simulation

The scrubber of the industrial urea production unit had to be modified after increasing the urea production capacity. It was modified based on the computational fluid dynamics modeling results. Increasing the number of outlet holes in the scrubber’s CAP improved the transient flow of carbamate and scrubber efficiency. In addition, the gas outlet flow rate in the initial design equaled an error level of 1%, while this rate was less than 7% when capacity was enhanced. All measurable parameters were measured and compared before scrubber modification (Plant-0) and after modification (Plant-1). The modification led to an increased average concentration of urea from 71.33 to 71.35 w%, enhanced CO2 purity from 98.81% to 99.09%, a decline in vapor consumed in the studied unit from 104.1 to 100.5 ton/h, and a reduction in the outlet ammonium of Prill tower’s synthesis unit from 11.5 to 0.81w% within the two-month interval. Before the modification of the scrubber, ammonium consumption, urea production, and ammonium/urea consumption index equaled 1494.9, 870 ton/day, and 0.5824, respectively, while reached 1503.3, 869.2 ton/day, and 0.5782, respectively after modifications. According to reported values, there was a 1.7 ton/day reduction in ammonium use and an 8.5 ton/day rise in urea production, resulting in considerable savings for the company.