Method and a system for obtaining methanol from foul condensate of a pulping process

Patent metadata

Field	Value
Publication number	US-11898309-B2
Application number	US-201916973196-A
Country	US
Kind code	B2
Filing date	Jun 11, 2019
Priority date	Jun 11, 2018
Publication date	Feb 13, 2024
Grant date	Feb 13, 2024

Abstract

Embodiments herein relate to a system ( 200; 300; 400; 500 ) for obtaining methanol from foul condensate ( 101 ) of a pulping process. The system ( 200; 300; 400; 500 ) comprises a primary stripper ( 102 ) arranged to strip the foul condensate ( 101 ) from pollutants, whereby a first methanol-containing condensate is obtained from the polluted stripper off gases (SOGs). The system ( 200; 300; 400; 500 ) also comprises a first acidification unit ( 202 ) arranged to acidify the first methanol-containing condensate. Further, the system ( 200; 300; 400; 500 ) comprises a secondary stripper ( 204 ) arranged to strip the acidified first methanol-containing condensate from pollutants to obtain a second methanol-containing condensate, and a distillation column ( 107 ) arranged to distil the second methanol-containing condensate from the secondary stripper ( 204 ) so as to obtain methanol. Embodiments herein also relate to a method performed in a system ( 200; 300; 400; 500 ) for obtaining methanol from foul condensate ( 101 ) of a pulping process.

First claim

The invention claimed is:

1. A method performed in a system for obtaining a methanol from a foul condensate of a pulping process, the method comprising:
stripping the foul condensate from first pollutants in a primary stripper to produce polluted stripper off gases (SOGs), whereby a first methanol-containing condensate is obtained from the polluted SOGs of the primary stripper by condensing the polluted SOGs of the primary stripper to obtain the first methanol-containing condensate;
acidifying the first methanol-containing condensate in a first acidification unit to produce an acidified first methanol-containing condensate where after the acidified first methanol-containing condensate is guided further to a secondary stripper;
stripping the acidified first methanol-containing condensate from second pollutants in the secondary stripper in order to remove the second pollutants together with second SOGs and to obtain a second methanol-containing condensate as a remaining condensate in the secondary stripper; and
distilling the second methanol-containing condensate from the secondary stripper in a distillation column so as to obtain the methanol and a remaining methanol-containing condensate.

2. The method according to claim 1 , further comprising
adding sulphite ions to the acidified first methanol-containing condensate.

3. The method according to claim 1 , further comprising
decanting the first methanol-containing condensate to obtain a decanted first methanol-containing condensate.

4. The method according to claim 3 , further comprising
acidifying the decanted first methanol-containing condensate.

5. The method according to claim 1 , further comprising
oxidizing the second methanol-containing condensate.

6. The method according to claim 1 , further comprising
decanting the second methanol-containing condensate.

7. The method according to claim 1 , further comprising
acidifying the second methanol-containing condensate.

8. The method according to claim 1 , further comprising
decanting the remaining methanol-containing condensate after the distilling.

9. The method according to claim 1 , further comprising
adding an amount of turpentine, or other hydrocarbons, to the first methanol-containing condensate when the amount of turpentine, or other hydrocarbons, in the first methanol-containing condensate is below a determined threshold level.

10. The method according to claim 1 , further comprising
condensing the second SOGs comprising the second pollutants from the secondary stripper into a polluted condensate;
extracting at least part of the second pollutants in the polluted condensate by mixing the polluted condensate with turpentine to obtain a remaining polluted condensate and turpentine mixture; and
decanting the remaining polluted condensate and turpentine mixture, so as to separate turpentine from the remaining polluted condensate and turpentine mixture.

11. The method according to claim 1 , further comprising
cooling the acidified first methanol-containing condensate in an upper equilibrium stage of the secondary stripper.

Assignees

• Valmet Oy

Inventors

• Wennberg Olle
• Saitton David Blomberg
• Nordlander Thomas

Classifications

• D21C11/0007 Primary

  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 title

• C07C29/80

  by distillation · CPC title

• D21C11/06

  Treatment of pulp gases; Recovery of the heat content of the gases; {Treatment of gases arising from various sources in pulp and paper mills; Regeneration of gaseous SO2, e.g. arising from liquors containing sulfur compounds} · CPC title

• C07C31/04

  Methanol · CPC title

• D21C11/00 Primary

  Regeneration of pulp liquors {or effluent waste waters} · CPC title