Abstract: The use of urea injection SNCR is enabled for rotary kilns of the type used to produce cement clinker. Rotary kilns are long cylinders that rotate about an inclined axis, with cement premix fed in at one end and a burner for heat at the other end. The geometry of the kilns and temperatures at the ends make introduction of ammonia or urea solutions ineffective or totally impractical. Urea prills can be injected at an initial velocity of at least 25, typically greater than 100, meters per second to reach into the kiln where a suitable temperature window for NO.sub.x reduction can be found.

Abstract: The tendency of aqueous solutions of urea and other NH-containing compositions to force instability of hardness factors has been found to be detrimental to processes and apparatus employing them. The reliability of these processes and apparatus is improved by the inclusion of hardness-suppressing compositions, which preferably include both a water-soluble polymer and a phosphonate. In particular, agricultural and NO.sub.x -reducing applications are improved, especially for solutions containing urea hydrolysis products and the salts of them.

Abstract: The present invention relates to a process for the use of a urea hydrolysate for nitrogen oxides reductions. More particularly, the process involves forming a urea hydrolysate under conditions of low pressure and introducing the hydrolysate into a combustion effluent under conditions effective for the reduction of nitrogen oxides.

Abstract: The tendency of aqueous solutions of urea and other NH-containing compositions to force instability of hardness factors has been found to be detrimental to processes and apparatus employing them. The reliability of these processes and apparatus is improved by the inclusion of hardness-suppressing compositions, which preferably include both a water-soluble polymer and a phosphonate. In particular, agricultural and NO.sub.x -reducing applications are improved, especially for solutions containing urea hydrolysis products and the salts of them.

Abstract: The present invention relates to a process for the use of a urea hydrolysate for nitrogen oxides reductions. More particularly, the process involves forming a urea hydrolysate and introducing the hydrolysate into a combustion effluent under conditions effective for the reduction of nitrogen oxides.

Abstract: The present invention relates to a process for the in-line hydrolysis of urea. More particularly, the process involves heating an aqueous solution of urea while flowing through a conduit to a temperature and for a time effective to hydrolyze urea to produce hydrolysis products comprising ammonium carbamate, ammonium carbonate, ammonium bicarbonate, and ammonia. The hydrolysis products are useful for the reduction of nitrogen oxides in combustion effluents without the generation of substantial amounts of nitrous oxide.