Process for recovery and recycle of ammonia from a reactor effluent stream
First Claim
1. A process for the recovery of ammonia from a reactor effluent stream comprising:
- contacting a gaseous reactor effluent stream containing ammonia with a first aqueous ammonium phosphate solution, in a quench zone, to absorb substantially all of the ammonia present in the reactor effluent stream to form a second aqueous ammonium phosphate solution richer in ammonium ions than said first aqueous ammonium phosphate solution;
contacting said second aqueous ammonium phosphate solution with a stripping gas, substantially free of carbon dioxide, to remove volatile impurities contained in said second aqueous ammonium phosphate solution;
heating said stripped second ammonium phosphate solution to an elevated temperature sufficient to reduce the amount of ammonium ions in said second aqueous ammonium phosphate solution back to substantially the same level present in said first aqueous ammonium phosphate solution to thereby generate a vapor stream comprising ammonia and an aqueous stream.
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Abstract
The present invention provides a novel process of recovering unreacted ammonia from a reactor effluent. This novel process includes at least the following steps: (1) quenching a reactor effluent containing ammonia with a first aqueous ammonium phosphate quench solution, wherein the pH of the solution is less than about 3.5, thereby absorbing ammonia to form a second aqueous ammonium phosphate solution richer in ammonium (NH4+) ions than the first solution but substantially free of dissolved CO2, (2) heating the second solution to an elevated temperature to reduce the amount of ammonium ions present to substantially the same level present in the first solution and thereby generate a vaporous stream containing ammonia, (3) recycling said vaporous stream containing ammonia to a reaction zone in a manner that minimizes the contamination of the reaction zone.
5 Citations
22 Claims
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1. A process for the recovery of ammonia from a reactor effluent stream comprising:
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contacting a gaseous reactor effluent stream containing ammonia with a first aqueous ammonium phosphate solution, in a quench zone, to absorb substantially all of the ammonia present in the reactor effluent stream to form a second aqueous ammonium phosphate solution richer in ammonium ions than said first aqueous ammonium phosphate solution;
contacting said second aqueous ammonium phosphate solution with a stripping gas, substantially free of carbon dioxide, to remove volatile impurities contained in said second aqueous ammonium phosphate solution;
heating said stripped second ammonium phosphate solution to an elevated temperature sufficient to reduce the amount of ammonium ions in said second aqueous ammonium phosphate solution back to substantially the same level present in said first aqueous ammonium phosphate solution to thereby generate a vapor stream comprising ammonia and an aqueous stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A process for the recovery of ammonia from a reactor effluent stream comprising:
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contacting a gaseous reactor effluent stream containing ammonia with a first aqueous ammonium phosphate solution, in a quench zone, to absorb substantially all of the ammonia present in the reactor effluent stream to form a second aqueous ammonium phosphate solution richer in ammonium ions than said first aqueous ammonium phosphate solution;
heating said second aqueous ammonium phosphate solution in a stripping zone to remove volatile impurities contained in said second aqueous ammonium phosphate solution and to form a stripped second ammonium phosphate solution;
heating said stripped second ammonium phosphate solution, in a decomposition zone, to an elevated temperature sufficient to reduce the amount of ammonium ions in said second aqueous ammonium phosphate solution back to substantially the same level present in said first aqueous ammonium phosphate solution to thereby generate a vapor stream comprising ammonia and an aqueous stream. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification