Process for the production of nitriles

Abstract

An improved process is provided for the production of nitriles and oxides from hydrocarbons by reaction with oxygen, air or a gas enriched in oxygen relative to air, preferably the latter, and ammonia where a nitrile is desired, in the presence of a suitable catalyst. An alkane, e.g. propane, is converted to an alkene in a catalytic dehydrogenator. The product stream is introduced into an ammoxidation reactor. The product formed therein is recovered in a conventional quench tower. The pressure of the gaseous effluent from the quench tower is raised and it is introduced into an absorber/stripper unit to form a recycle stream containing unreacted alkane and alkene as well as a minor amount of oxygen, typically 1-2 percent by volume, and a waste stream comprising the remainder of the quench tower gaseous phase. The recycle stream is introduced into a selective oxidation unit to remove the oxygen therefrom and then recycled to the dehydrogenator. Flammability of the quench tower gaseous effluent and the waste stream from the absorber/stripper is minimized by assuring that the nonflammability index (NFI) thereof is within certain limits. The desired NFI is related to the total hydrocarbon content of the stream and may be achieved, if required, by the addition thereto of a gaseous flame suppresor. The gaseous flame suppressor is removed with the absorber/stripper unit waste stream which may advantageously be combusted to provide energy for the process. A PSA unit may be utilized to remove excess hydrogen from the dehydrogenator effluent. The dehydrogenator may be a multistage dehydrogenator.