This patent describes technology for generating ammonia from urea. The method is based on the hydrolysis of an aqueous solution of urea and/or biuret by heating under pressure to form a mixture of ammonia, carbon dioxide and water. The gas mixtures produced are useful for supplying ammonia at controlled pressure and rate of flow for many industrial applications without the risks and hazards associated with the transportation and on-site storage of ammonia, thereby providing a significant safety advantage over present industrial practice.

Methods for the production of ammonia from urea and/or biuret, and uses for NOx and/or particulate matter removal

Processes and apparatus for quantitatively converting urea to ammonia on demand are disclosed. One process includes the steps of: receiving a demand rate signal for ammonia; feeding reactants including urea and water into a reactor to provide a reaction mixture; and controlling temperature and pressure in the reactor to produce a gaseous product stream including ammonia and carbon dioxide at substantially constant concentrations. Another process includes the steps of: feeding molten urea or solid urea to a reactor; feeding water (liquid or steam) to the reactor; and reacting the urea and water at elevated temperature and pressure to form a gaseous product stream including ammonia and carbon dioxide.

Processes and apparatus for quantitatively converting urea to ammonia on demand

A process for purifying the effluent originating from urea production plants, consisting of three successive treatment stages, namely stripping of the volatile components, thermal hydrolysis of the urea and biuret in a plurality of zones traversed with piston flow, and final stripping of the volatile components produced by the hydrolysis.

Process for purifying the effluent from urea production plants

A continuous process for removal of ammoniacal nitrogen from water is disclosed. This process is useful for maintaining water quality in aquaculture operations, e.g., fish hatcheries and the like. A particulate stream of zeolitic ion exchange material is circulated continuously through an exchanger and a regenerator. An aqueous process stream containing ammoniacal nitrogen, e.g., ammonia, is passed through the exchanger in continuous counter current liquid-solid contact with a stream of particulate, ammoniacal nitrogen-sorbing zeolitic ion exchange material of natural or synthetic origin. A treated liquid water stream having a reduced ammoniacal nitrogen content exits from the exchanger, as does a stream of ammoniacal nitrogen-enriched particulate zeolitic ion exchange material. The latter stream is regenerated in the regenerator at a temperature of about 350° C. to about 650° C. while an oxygen-containing gas stream, e.g., air, is passed in continuous counter current gas-solid contact therewith. Gases emanating from the regenerator are used to preheat the ammoniacal-nitrogen enriched particulate material that enters the regenerator. The regenerated stream of particulate, ammoniacal nitrogen-sorbing zeolitic ion exchange material is recycled to the exchanger.

Process for continuous removal of ammoniacal nitrogen from aqueous streams

The present invention provides a system and a process for removing contaminants such as CO2 and mobile cations and anions from aqueous solutions. The system and the process contemplate the use of thermally sterilizable aqueous polishing agents such as thermally sterilizable ion exchange resins and as a result, the need for chemical and/or mechanical microbial control or inhibition techniques is obviated. Therefore, the present invention will be especially useful in submarine and spacecraft applications where the need exists for reduced weight and volume water processing systems.

Process employing thermally sterilizable aqueous polishing agents

An improved process for the removal of urea, ammonia, and carbon dioxide from dilute aqueous solutions thereof by hydrolyzing the urea, and thereafter desorbing ammonia and carbon dioxide. The dilute solution containing urea is passed into the top portion of a reaction column and caused to flow downward and countercurrent to a heating and stripping gas while maintaining the reaction column at a pressure of between about 10 and 30 bar, and a top column temperature of between about 170° and 220° C. and a bottom column temperature of between about 180° and 230° C. The resulting liquid stream removed from the bottom of the reaction column, comprised of a substantially urea-free aqueous solution of ammonia and carbon dioxide, is introduced into a desorption zone wherein, at a pressure of between about 1 and 5 bar, ammonia and carbon dioxide are removed therefrom.

Pierre Gerard Marie Bernard Bruls

Papers

Process for the removal of urea, ammonia, and carbon dioxide from dilute aqueous solutions