Diagnostic tool and process for assessing thermal urea gasification performance

An apparatus comprising:

• means for introducing an aqueous solution of urea into a reactor having hot gases therein and subjecting the aqueous urea to temperatures for a time to assure the gasification of the aqueous urea and form a thermal gasification product stream containing NH3 and HNCO;
• means for taking a sample stream from the gasification product stream;
• means for contacting the sample stream with a hydrolysis catalyst in the presence of sufficient water to convert HNCO to NH3 and form an ammonia sample stream;
• and means for analyzing the ammonia sample stream for NH3.

A process for controlling urea gasification by a process that includes converting all of a gasified urea to ammonia in a small sample stream as a means for determining the effectiveness of urea gasification by the urea gasification reactor, the process comprising:

• a. introducing an aqueous solution of urea into a reactor having hot gases therein and subjecting the aqueous urea to temperatures for a time to assure the gasification of the aqueous urea and form a thermal gasification product stream containing NH3 and HNCO;
• b. taking a sample stream from the gasification product stream;
• c. contacting the sample stream with a hydrolysis catalyst in the presence of sufficient water to convert all HNCO in said sample stream to NH3 and form an ammonia sample stream;
• d. analyzing the ammonia sample stream for NH3 concentration;
• e. generating an observation signal representative of the NH3 concentration;
• f. comparing the observation signal to a reference value;
• g. generating a control signal representative of the results of the comparison;
• and
• h. operating said reactor in response to said control signal.

A process for monitoring the operation of a urea gasification reactor by a process that includes converting all of a gasified urea to ammonia in a small sample stream as a means for determining the effectiveness of urea gasification by the urea gasification reactor, the process comprising:

• a. introducing an aqueous solution of urea into the reactor having hot gases therein and subjecting the aqueous urea to temperatures for a time to assure the gasification of the aqueous urea and form a thermal gasification product stream containing NH3 and HNCO;
• b. taking a sample stream from the gasification product stream;
• c. contacting the sample stream with a hydrolysis catalyst in the presence of sufficient water to convert all of the HNCO to NH3 and form an ammonia sample stream;
• d. analyzing the ammonia sample stream for NH3 concentration;
• e. generating an observation signal representative of the NH3 concentration;
• f. comparing the observation signal to a reference value;
• g. generating an alarm signal when results of the comparison are outside preset limits;
• and
• h. generating an alarm in response to said alarm signal.