CHE.02 Production of Blue Urea – A New Path to Greener Synthesis

• Masab Bokhari
• Lauren Landwehr
• Kareem Muhammad
• Namrata Patel

As a cornerstone of the agricultural industry and the most popular nitrogen-based fertilizer, the chemical synthesis of urea (CON2H4) from ammonia (NH3) and carbon dioxide (CO2) is a crucial operation involved in feeding the world. There are twenty-two urea manufacturing facilities in the United States, yet our country is the third largest importer of urea. Globally, the current urea production process requires elevated temperatures and pressures to initiate the formation of a chemical intermediate known as ammonium carbamate. In this project, we demonstrate the pilot-scale application of a bench-scale urea production process that forms this intermediate at ambient conditions in the presence of ethanol. This new path of urea production offers potential reduction in energy consumption costs associated with gas compression, heating, and cooling. In addition, the lowered operating temperatures prevent the undesired formation of biuret, which is an effective poison to fertilized agricultural plants. The scaled-up process is divided into four sections: 1) Raw Material Processing, 2) Synthesis and Recycling, 3) Product Separation, and 4) Evaporation and Granulation. A technical and economic evaluation of this innovative urea synthesis process also investigates the effects of decoupling ammonia and urea production. The pilot-scale plant designed will be in Southern Illinois with a production capacity of 10,000 tons per year of low-biuret grade, granulated urea with a 100 percent conversion of carbon dioxide. Our feedstock is ammonia purchased from an offsite producer, and carbon dioxide captured from a neighboring steel plant. Outside of the raw materials, the consumables include ethanol and urea-formaldehyde, and the utilities are high-pressure and low-pressure steam, cooling water, and electricity. Byproducts are limited to water, which can be exploited as a cooling water utility. Due to high ammonia purchase costs, the annual profit margin is calculated as a small percentage of the initial investment. It is postulated that scaling up the process and/or producing our ammonia feedstock onsite would increase profitability.