Newbie seeking advice on CO2 stripping

Answering your first question: What is the principle behind an N/C ratio analyzer, and are there any online analyzers? Answer: The basis is that under certain temperature and pressure conditions, there is a linear relationship between the density of the liquid exiting the synthesis tower and the NH3/CO2 ratio; thereby, the NH3/CO2 value in the liquid exiting the synthesis tower can be determined. A vertically vibrating tube, known as a density sensor, is used to generate a continuous on-line measurement signal of the liquid density. The working principle of the density sensor is based on resonance frequency technology; when the liquid flowing out of the synthesis tower passes through the vibrating tube, its resonance frequency changes accordingly. This frequency is a function of the density of the liquid in the tube, allowing for the measurement of very accurate density values. Stamicarbon holds patents for online analysis, and several companies in China are using this technology; its operation is relatively reliable. The following points should also be taken into consideration during use: 1 To ensure the safe operation of the NH3/CO2 analyzer, it should only be used when the synthesis tower is operating properly, with pressure and temperature within the normal operational parameters. The conditions that the synthesis tower must meet are: it has been in operation for more than 1 hour, the temperature reaches above 175°C, the pressure reaches above 13 MPa, and the liquid flow rate from the synthesis tower is stable. 2 NH3/CO2 analyzers have a certain measurement range, with the typical value corresponding to the operating range under normal production conditions. 3 It is necessary to strictly control the temperature and pressure of the ammonia-to-carbon ratio measurement system within the designed process parameters in order to ensure the accuracy of density measurements. 4 Urea crystallization must always be prevented in the density apparatus and the NH3/CO2 analysis system. When the pressure or temperature in the urea sampling line is too high, its flushing system will automatically flush the analysis system.

Please check out the link: http://bbs.hcbbs.com/viewthread.php?tid=105588 (Application of the N/C ratio in the liquid phase of urea in large-scale fertilizer plants). It contains detailed information that will surely be useful to you.