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Process for producing pure concentrated ammonia

  • US 4,049,782 A
  • Filed: 03/03/1976
  • Issued: 09/20/1977
  • Est. Priority Date: 11/14/1975
  • Status: Expired due to Term
First Claim
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1. A process for the recovery of pure concentrated ammonia from a gas water resulting from the condensation or washing of coal degasification or coal gasification gases comprising the steps of:

  • a. filtering said gas water;

    b. extracting the filtered gas water of step (a) with di-isopropyl ether as a dephenolating solvent to produce a dephenolated water containing NH3, HCN and traces of residual solvent and a phenol-laden solvent phase;

    c. recovering solvent from phenols of said solvent phase and recycling the recovered solvent to step (b);

    d. stripping the dephenolated gas water of step (b) to produce a gas phase containing CO2, H2 S, HCN, NH3 and residual solvent;

    e. chemically washing ammonia from the gas phase of step (d) to produce a substantially ammonia-free gas phase and an ammonia-laden absorbent phase;

    f. separating ammonia from said absorbent of the ammonia-laden absorbent phase, collecting the separated ammonia product, and recycling said absorbent to step (e);

    g. washing HCN from the ammonia-free gas phase of step (e) to produce a gas containing traces of residual solvent;

    h. scrubbing residual solvent from the gas of step (g) with circulating phenol to produce a phenol-scrubbed gas and a solvent containing phenol;

    i. distilling solvent containing phenol produced in step (h) to separate the solvent thereof from the phenol delivering the solvent to step (b) and returning the phenol to step (h); and

    j. afterscrubbing the phenol-scrubbed gas of step (h) at least in part with filtered gas water from step (a).

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