The determination of nitrogen-to-carbon ratio in urea synthesis using gamma radiation technique and comparison with oscillation technique

Accurate ratio control of the components in the urea synthesis section plays a crucial role in achieving stable and efficient operation of the urea process. Additionally, obtaining the optimum yield of urea in the stripping urea process requires the reactants to be present at a specific ratio, known as the N/C ratio. In this study, the gamma radiation technique was employed to measure the density of urea, which has a linear relationship with the N/C ratio. In this technique, a ¹³⁷Cs source and a NaI(Tl) detector were positioned on opposite sides of the outlet pipe to measure the density of urea under processing conditions. The measurements were conducted with an accuracy of better than 0.5 % at 2σ. The NC meter was capable of measuring a density range between 500 kg/m³ and 2000 kg/m³. The measured results were compared with data acquired using the oscillation technique, showing a strong agreement between the two methods. Consequently, the gamma radiation technique demonstrates superior advantages over the oscillation technique and other methods due to its non-contact, non-invasive, non-destructive, online, cost-effective, and real-time characteristics.