High purity HCN from acrylonitrile co-production

Patent metadata

Field	Value
Publication number	US-10647663-B2
Application number	US-201615745166-A
Country	US
Kind code	B2
Filing date	Jul 22, 2016
Priority date	Jul 22, 2015
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

Disclosed is a process for co-manufacture of ACRN and HCN with improved HCN selectivity and reduced solids formation in a shared product recovery section.

First claim

The invention claimed is:

1. A process for co-manufacture of ACRN and HCN comprising:
(a) operating an ACRN process and a HCN process in parallel in separate reactor systems to co-produce an ACRN reactor product stream and a HCN reactor product stream comprising HCN, respectively, wherein the HCN is produced from reaction of methane, ammonia, and oxygen or from methane and ammonia;
(b) quenching the co-produced ACRN reactor product stream and the HCN reactor product stream in a quench column with a first acid stream at pH of 7.0 or less to produce a quenched combined reactor product stream and recovering a first water purge from the quench column;
(c) in a single recovery/purification system, feeding the quenched combined reactor product stream comprising the quenched HCN reactor product stream and the quenched ACRN reactor product stream to an absorber column with water, to produce a combined product stream, wherein quenching the HCN reactor product stream along with the ACRN reactor product stream decreases the weight ratio of ACRN to HCN in the quenched combined reactor product stream so that the combined product stream from the absorber column has a weight ratio of ACRN to HCN of about 12 to 1 or less;
(d) treating the combined product stream sequentially in a recovery column, a decanter having an aqueous layer and an organic layer, and a heads column, wherein pH is controlled by addition of a second acid at pH of 7.0 or less in the absorber column and the recovery column, and at pH less than 4.5 in the decanter and heads column; and
(c) separately treating the first water purge to recover ammonium salt and/or ammonia.

2. The process of claim 1 wherein the first acid and the second acid independently comprise an organic or inorganic acid.

3. The process of claim 2 wherein the first acid and the second acid are independently sulfuric acid or phosphoric acid.

4. The process of claim 1 further comprising operating the HCN process at ≤80% ammonia conversion.

5. The process of claim 1 further comprising charging the HCN reactor product from the HCN process to an ammonia sorption column upstream of the absorber column.

6. The process of claim 5 further comprising flowing phosphoric acid at pH of ≤7.0 to the ammonia sorption column and recovering diammonium phosphate and/or ammonium phosphate.

7. The process of claim 5 further comprising flowing sulfuric acid at pH of ≤7.0 to the ammonia sorption column and recovering ammonium sulfate.

8. A process according to claim 1 wherein the weight ratio of ACRN to HCN in the combined product stream is ≥2 to 1 and ≤12 to 1.

9. A process according to claim 1 wherein the methane for producing the HCN of step (a) is supplied to the reaction in a methane charge stream containing ≥0.05 to ≤20 weight percent C 2 and heavier hydrocarbons.

10. The process of claim 9 wherein the methane charge stream contains ≥0.5 to ≤10 weight percent C 2 and heavier hydrocarbons.

11. The process of claim 10 wherein the methane charge stream contains ≥1 to ≤5 weight percent C 2 and heavier hydrocarbons.

12. The process of claim 10 wherein the methane charge stream contains ≥2 to ≤4 weight percent C 2 and heavier hydrocarbons.

13. The process of claim 1 wherein the weight ratio of ACRN to HCN in the combined product stream is ≥2 to 1 and ≤5 to 1.

Assignees

• Invista North America Sarl

Inventors

• Herzog Benjamin D
• Kantak Milind V

Classifications

• C07C253/34 Primary

  Separation; Purification · CPC title

• C01C1/28

  Methods of preparing ammonium salts in general · CPC title

• C01C3/0212

  from hydrocarbons and ammonia in the presence of oxygen, e.g. the Andrussow-process · CPC title

• C01C3/0229

  from hydrocarbons and ammonia in the absence of oxygen, e.g. HMA-process · CPC title

• C01C3/0295

  Purification · CPC title