PROCESS AND APPARATUS FOR RECOVERY AND REUSE OF AMMONIA IN A LIQUID AMMONIA FABRIC TREATING SYSTEM

摘要

PROCESS AND APPARATUS FOR RECOVERYAND REUSE OF AMMONIA IN A LIQUIDAMMONIA FABRIC TREATING SYSTEMAbstract of the DisclosureThe disclosure is directed to a system for the recoveryof spent ammonia, in connection with the processing of fabricsand the like with liquid ammonia, and concerns particularly theelimination from the recovered ammonia of undesired water.Economic processing of fabrics by liquid ammonia requiresrecovery and reuse of substantial quantities of ammonia. In thecourse of processing, the ammonia unavoidably becomes contaminatedwith water. Separation of water from ammonia on a laboratorylevel or, in any kind of batch processing is a theoretically simplematter and can be coped with by conventional differential evapo-ration techniques, or otherwise. However, in a continuouslyoperating processing line where large quantities of anhydrousliquid ammonia are being used as the treating medium, wateraccumulates rapidly, not only from the fabric being processed,but also from a certain inevitable amount of air leakage in thesystem, Because so much of any given increment of the treatingmedium must be recycled, as compared to that actually "used up"in the treating process, water accumulates rapidly in the systemand must be removed on a continuous basis. The specificationdiscloses a unique and highly efficient procedure for removal ofwater by effecting condensation of water and ammonia vapors, con-stituting the process effluent, by feeding the effluent to a de-superheating vessel, where it is brought into direct contact witha body of low temperature liquid ammonia. This is done in con-junction with a preliminary low temperature condensation of theeffluent in a non-contact heat exchange stage. The condensed bodyof liquid ammonia in the desuperheater vessel, including residualcondensed water from the process effluent combined with re-lique-fied ammonia, forms the feed supply of liquid ammonia solutionto the process. The condensed water, which in the new processconstitutes a portion of the feed supply, is applied to the fabricbeing treated, along with the liquid ammonia. Typically, someof the water is carried away with the processed fabric as a con-stituent of its moisture content. The remainder, which is drivenoff as steam in the process, is recycled.- 1a -