into a gaseous mixture containing nh 3 and co 2 in accordance with the following formula the gaseous mixture containing ammonia co 2 and water vapor is withdrawn from the hydrolyzer through valved conduit 61 the broad concept of urea hydrolysis is a well known concept and a detailed description thereof is not believed to be necessary to those skilled in the art of this invention for further description of urea hydrolysis reference is hereby made to the hereinabove cited references it should be mentioned however that the hydrolysis reaction is overall endothermic in nature and as such suitable means not shown such as steam or electric heater must be provided to maintain the urea solution passing through the hydrolyzer at an efficient temperature for hydrolyzation conduit 61 carries a gaseous mixture containing a high proportion of ammonia i e 15 to 35 percent by volume which is too high for most uses i e ammonia content as a percent cent of the air mixture in scr applications depending upon particular circumstances should generally be in the range of 3 to 10 which is significantly below the explosion limit for such a mixture accordingly the preferred embodiment herein also incorporates the dilution portion which comprises a dilution blower 62 which pulls filtered air through filter 64 into the dilution conduit 63 a suitable air heater 66 is provided for heating the dilution air to insure that.