The following article was recently published by Jim Lines and appeared in the June 2017 issue of World Fertilizer magazine.
Ejector systems are critical to the final concentration of a urea solution. Regardless of the end product, whether produced by granulation or prilling, ejector systems establish evaporator pressures that permit the removal of water to concentrate the urea solution at temperatures sufficiently low enough to minimize biuret formaton.
There are several process technologies for urea production. Saipem/Snamprogetti, Maire Tecnimont/Stamicarbon, Toyo Engineering Corp., Casale and NIIK offer the most frequently used. For each process technology, the ejector systems are critical to plant throughput and product quality. While critical to the success and profitability of a urea plant, ejector systems are viewed as not generally well understood. The thermodynamics of ejector performance in not widely known and the vacuum condensers within an ejector system cannot be designed with conventional heat exchanger software.
This article provides a deeper review of ejectors and vacuum condensers in urea concentration processes so that specifiers, evaluators, purchasers and users of this critical process equipment understand the salient considerations necessary to provide reliable plant performance. Download the complete article that covers:
- Ejector systems for urea concentration processes
- Steam supply conditions
- Ejector performance curve
- Variables that affect ejector performance
- Booster ejector flushing
- Vacuum condensers
- Ammonia emission from ejector system
- Numerous charts and equations