Nitrogen+Syngas 333 Jan-Feb 2015
28 February 2015
Problem No. 28: How to avoid hot prills in the prill tower bottom
Hot prills can easily cause caking because heat transfer and moisture transfer take place due to the temperature difference between the hot prills and the other prills. Caking is the process of building crystal bridges between the urea particles. Caking leads to lump formation and consequently dust formation when these lumps are crushed. This all leads to poor product quality and customer complaints, but how can hot prills be avoided? A Round Table discussion about an incident during the cleaning of a scraper (see Plant Manager+ Problem No. 27) triggered a subsequent discussion on how to avoid hot prills; hot prills obviously cause more fouling of a scraper.
