AMMOGEN provides gaseous ammonia to fossil-fuel-burning plants to operate pollutioncontrol systems such as DeNOx/DeSOx SCR, SNCR and flue-gas treatment units. This process produces gaseous ammonia onsite and on demand with harmless and easy-to-handle feedstocks—urea and water. It eliminates the hazard of transporting and storing toxic compounds such as anhydrous or aqueous ammonia. Products: The gaseous stream of ammonia (15–35%vol.), carbon dioxide and water vapor.
Dry urea enters the dissolver/storage tank where it is dissolved using lean-recycle solution and condensate. The stirrer reduces mixing time, and the rich-urea solution (20–60%wt) is pumped to the hydrolyzer through the economizer where the lean solution sensible heat is recovered. A multistage hydrolysis, at 180–250°C and 15–30 bar, is done in the baffled hydrolyzer, while the reaction products, i.e., ammonia and carbon dioxide, are removed by a stripping fluid (typically steam). The heat of reaction is supplied by an internal heater and stripping fluid. After the urea decomposition, the lean solution is flashed at atmospheric pressure in the flash separator, from where almost pure water is recycled to the dissolver. The flashed vapor, rich in NH3, joins the main stream produced by the hydrolyzer and both are sent to the static mixer and diluted with air before delivery to the ammonia-injection grid of the flue-gas treatment system.
Main advantages include:
• Gaseous ammonia produced onsite and on demand
• Utmost safety (no governmental reportable amounts or contingency plans)
• Urea feedstock is harmless, easy-to-handle and widely available
• Simple and safe noncatalytic process
• No carryover of compounds that can damage SCR systems
• Very rapid response time and maximum turndown availability
• Quick startup, shutdown and standby
• Automatic operation and low maintenance
• Limited plant footprint for easier installation; also can be skid-mounted or module
• Low capital and operating cost
• Capacity from several to thousands kg/h of ammonia.
Licensors: SIIRTEC NIGI and HERA LLC