How to determine whether NH3/CO2 and H2O/CO2 are appropriate in urea production
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In actual production, due to inaccurate analysis data or delayed reporting of such data, operators can determine the levels of NH3/CO2 and H2O/CO2 by referring to the temperature readings from the thermocouples located after the urine tower before it enters the pre-distillation stage. The level of H2O/CO2 is determined based on the temperature difference between the top and bottom of the synthesis tower; under the designed conditions, this temperature difference is kept at 6 degrees, resulting in a H2O/CO2 ratio of 0.65
Hehe, I’m planning to publish a series of articles on my understanding of urea production, in the hope of sharing it with beginners. I used to struggle a lot to find information on this topic; I hope it can be helpful for those who are just starting out in urea production
It was a great experience; thank you so much. :handshake :handshake
Are you referring to the stripping method or the full circulation of aqueous solution? The ratio of H2O/CO2 is 0.67; I think it should be the full circulation of aqueous solution
:Handshake: The level of the urea-ammonia-carbon ratio can be determined and analyzed through the following methods: 1. It is necessary to check the temperature difference between the top and bottom of the synthesis tower. Keep it at 179 degrees, plus or minus 1 degree, at 2 o’clock. 2. Observe the changes in the steam pressure in the heating chamber; high pressure will lead to reduced decomposition rates and evaporation rates, as well as an increased load on the absorption tower. 3. It can analyze whether the ammonia content in a liquid sample exceeds the standard. 4. It is necessary to analyze the conversion rate of synthetic urea. The level of the carbon-to-urea ratio in urea water can be analyzed from the following aspects ； 1. It is necessary to check the changes in the synthesis conversion rate. 2. It is necessary to monitor the load changes in the urea absorption tower. 3. Check whether the circulating fluid from stages 1 and 2 is being discharged. 4. If the water carbonation level remains above the acceptable limit for a long time, it will cause corrosion of the equipment. In short: I think it’s still a matter of getting the right amount. As long as the concept of quantity can be controlled, the system can operate stably. :handshake :handshake
What you’re referring to seems to be the full-circulation aqueous solution method. It mainly determines the water-carbon ratio based on temperature, and also takes into account the amount of water added to one absorption tower
In the full-circulation aqueous solution method, the control and determination of NH3/CO2 and H2O/CO2 cannot rely solely on theory. In actual production, the temperature differences between the upper, middle, and lower sections of the synthesis tower are influenced not only by NH3/CO2 and H2O/CO2 but also by changes in load. Different plants have their own characteristics; in our plant, the temperature read by the thermocouples of the material flowing after the urea tower before it enters the pre-distillation stage is always above 116 degrees