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Process for recovery and recycle of ammonia from an acrylonitrile reactor effluent stream using an ammonium phosphate quench system

  • US 20010006614A1
  • Filed: 12/18/2000
  • Published: 07/05/2001
  • Est. Priority Date: 12/23/1998
  • Status: Abandoned Application
First Claim
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1. A process for the recovery of unreacted ammonia from the effluent obtained from a reaction zone wherein oxygen, ammonia and a hydrocarbon are reacted at an elevated temperature in the presence of an ammoxidation catalyst to produce an unsaturated nitrile comprising the steps of:

  • quenching the effluent containing the nitrile and unreacted ammonia with an aqueous ammonium phosphate solution having an initial ratio R of ammonium ions to phosphate ions to absorb substantially all of the unreacted ammonia present in the reactor effluent to form an ammonium phosphate solution having an increased ratio R of ammonium ions to phosphate ions;

    heating the solution to an elevated temperature sufficient to reduce the ratio R of ammonium ions to phosphate ions and to generate a vaporous stream containing ammonia;

    passing the heated solution through a 31P nuclear magnetic resonance detector to detect a chemical shift of a 31P nuclear magnetic resonance peak;

    determining the ratio R of ammonium ions to phosphate ions in the solution based on the chemical shift; and

    controlling the heating step to maintain the initial ratio R within a desired range.

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