Urea] [About DNT]
[NOx Optimization] [Publications]
UREA - TO - AMMONIA CONVERSION SYSTEMS
External conversion of urea to ammonia gas for delivery to the Ammonia Injection Grid of an SCR system.
In-situ conversion of urea to ammonia in the hot exhaust gases of an internal combustion engine, combustion turbine, flare, or incinerator.
Retrofit application of existing, hydrolyser-vessel-type, urea to ammonia reactors.
In-Situ conversion of urea to ammonia in Power Boilers for SNCR purposes.
In-Situ conversion of urea to ammonia in a Cement Kiln for SNCR purposes.
In-Situ conversion of urea to ammonia in a Fluid Bed Combustor for SNCR purposes.
External conversion of urea to ammonia for corrosion protection in certain SNCR systems.
DNT's Patent Pending Approach utilizes direct application of high temperatures to dry urea or urea solutions. The source of heat can be from steam, hot air, or electricity.
Catalytic NOx systems require ammonia - which is tricky to receive, store, and handle. Many communities and facilities are looking for an alternative - which generally means on-site conversion of urea to ammonia. There have been several installations of such systems in the USA - most commonly using the application of heat to a tea-kettle-type vessel. These patented processes suffer from one or all of the following symptoms:
Corrosion. The pressure vessel shows internal pitting above the water line. The oxidized material settles to the bottom of the vessel and accumulates. This sludge contains chromium and other heavy metals which then becomes a waste disposal issue.
Heavy Liquid Accumulation. Partial urea decomposition products combine with themselves or with whole urea to form heavy nitrogen-containing compounds - which do not easily break down at the typical 300 degF operating temperature of the vessel. The result is a slow and steady increase in liquid phase Specific Gravity.
Black Sludge. The compounds discussed in the previous item can be entrained in the gas phase and carried to down stream piping, AIG, and catalyst. Extra heat trace and insulation can help avoid cold spot condensation, but is far from solving the problem.
Instrumentation Failure. The oxidized iron causes magnetic level instruments to stick. The highly corrosive liquid in the vessel destroys DP cells.
There is no known cure for these fundamental process flaws.
The DNT OTA system solves these problems by judicious use of higher temperatures, at fractional residence times and low pressures. The technology can be applied as retrofit to existing units, or as a stand-alone Unit Operation. The advantages are summarized as follows:
Greatly Reduced Installed Cost, with complete system redundnacy
Easily retrofitted to existing urea to ammonia vessels
Lower Operating Cost when looking a overall system energy use
Extremely Quick Response Time
No Overpressure Relief Vent
Kinder to 316L Components