PROCESS FOR PRODUCING AMMONIA AND SULFURIC ACID FROM A STREAM COMPRISING AMMONIUM SULFATE

• US 20080056983A1
• Filed: 08/29/2007
• Published: 03/06/2008
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Iogen Energy Corporation (Iogen Corporation)
• Original Assignee: Iogen Energy Corporation (Iogen Corporation)
• Inventors: Curren, Meredith, Foody, Brian, Tolan, Jeff
• Granted Patent: US 7,632,479 B2
• Time in Patent Office: Days
• US Class Current: 423/531
• CPC Class Codes: C01B 17/745 from sulfates
• CPC Class Codes: C01C 1/028 from ammonium sulfate or sulfite
• CPC Class Codes: D21C 11/0007 Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for volatile compounds obtained by decomposition of spent liquors in order to regenerate them D21C11/125; compounds obtained by fractionating the liquors in order to regenerate them D21C11/0042
• CPC Class Codes: D21C 3/04 with acids, acid salts or acid anhydrides D21C3/003 and D21C3/222 take precedence
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A process for producing ammonia and sulfuric acid from a stream comprising ammonium sulfate is provided. The process comprises the steps of heating the stream to produce ammonia and a decomposition product comprising one or more than one of a bisulfate salt, a pyrosulfate salt, or a combination thereof. The ammonia produced is recovered, and water is added to the decomposition product to produce a stream comprising the decomposition product. The stream comprising the decomposition product is processed by acid retardation to obtain a sulfuric acid stream and a stream comprising one or more than one sulfate salt.

Claims

1. A process for producing ammonia and sulfuric acid from a first stream comprising ammonium sulfate, the process comprising the steps of:

(i) heating the first stream comprising ammonium sulfate thereby producing ammonia and a decomposition product comprising a sulfate salt selected from the group consisting of bisulfate salt, a pyrosulfate salt and a combination thereof;

(ii) recovering the ammonia produced in step (i);

(iii) adding water to the decomposition product produced in step (i) to produce a second stream comprising a sulfate salt, a bisulfate salt, sulfuric acid or a combination thereof;

(iv) separating sulfate salt from sulfuric acid in the second stream produced in step (iii) to obtain a third stream comprising sulfuric acid and a fourth stream comprising one or more than one sulfate salt, wherein said separating comprises acid retardation; and

(v) recovering the sulfuric acid obtained in step (iv).

2. The process of claim 1, wherein the first stream comprising ammonium sulfate originates from a stream produced by pretreatment of a lignocellulosic feedstock with sulfuric acid and wherein sulfate present in the stream comprising ammonium sulfate originates, in whole or in part, from sulfuric acid added during said pretreatment.

3. The process of claim 2, further comprising using ammonia recovered in step (ii) to adjust the pH of said stream produced by pretreating said lignocellulosic feedstock with sulfuric acid.

4. The process of claim 2, wherein said sulfuric acid added during pretreatment is obtained from step (v).

5. The process of claim 1, wherein the one or more than one sulfate salt produced in step (iv), or a portion thereof, is added to the first stream comprising ammonium sulfate in the step of heating (step (i)).

6. The process of claim 1, wherein the first stream comprising ammonium sulfate further comprises a sulfate salt selected from the group consisting of potassium sulfate, sodium sulfate, magnesium sulfate, calcium sulfate and a combination thereof.

7. The process of claim 6, wherein the first stream comprising ammonium sulfate further comprises potassium sulfate.

8. The process of claim 1, wherein the decomposition product produced in step (i) comprises a bisulfate salt, which bisulfate salt is selected from the group consisting of ammonium bisulfate, potassium bisulfate, sodium bisulfate, magnesium bisulfate, calcium bisulfate and a combination thereof.

9. The process of claim 8, wherein the bisulfate salt comprises ammonium bisulfate.

10. The process of claim 8, wherein the bisulfate salt comprises potassium bisulfate

11. The process of claim 1, wherein the decomposition product produced in step (i) comprises a pyrosulfate salt, which pyrosulfate salt is selected from the group consisting of ammonium pyrosulfate, potassium pyrosulfate, sodium pyrosulfate, magnesium pyrosulfate, calcium pyrosulfate and a combination thereof.

12. The process of claim 11, wherein the decomposition product comprises ammonium pyrosulfate.

13. The process of claim 11, wherein the decomposition product comprises potassium pyrosulfate.

14. The process of claim 1, wherein the one or more than one sulfate salt in step (iv) is selected from the group consisting of ammonium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate and a combination thereof.

15. The process of claim 14, wherein the one or more than one sulfate salt in step (iv) comprises ammonium sulfate.

16. The process of claim 14, wherein the one or more than one sulfate salt in step (iv) comprises potassium sulfate.

17. The process of claim 1, wherein the first stream comprising ammonium sulfate originates from a stream produced by pretreatment of a lignocellulosic feedstock with ammonia and wherein ammonia present in the stream comprising ammonium sulfate originates, in whole or in part, from ammonia added during said pretreatment.

18. The process of claim 17, further comprising using the sulfuric acid recovered in step (v) to adjust the pH of said stream produced by pretreating said lignocellulosic feedstock with ammonia.

19. The process of claim 18, wherein said ammonia added during pretreatment is obtained from step (v).

20. The process of claim 1, wherein the step of heating the first stream comprising ammonium sulfate (step (i)) is carried out at a temperature of between about 300°

C. and about 450°

C.

21. The process of claim 1, wherein the first stream comprising ammonium sulfate originates from a stream produced by acid hydrolysis of a lignocellulosic feedstock with sulfuric acid and wherein sulfate present in the stream comprising ammonium sulfate originates, in whole or in part, from sulfuric acid added during said acid hydrolysis.

22. The process of claim 1, wherein the second stream has a dissolved solids concentration of about 25 g/L to about 500 g/L.