Energy and water recovery from pressure oxidation flash vessel steam

Patent metadata

Field	Value
Publication number	US-2016186288-A1
Application number	US-201314653232-A
Country	US
Kind code	A1
Filing date	Dec 20, 2013
Priority date	Dec 20, 2012
Publication date	Jun 30, 2016
Grant date	—

Abstract

The invention relates to a method of recovering energy and water from pressure oxidation flash steam comprising a step wherein a first flash steam directly obtained from a flash vessel is contacted with a first recirculating condensate having a first low condensate temperature to con-dense at least part of the water vapour comprised in the said first dirty flash steam on the first recirculating condensate and simultaneously to heat the said first recirculating condensate to obtain a first recirculating condensate having a first high condensate temperature and a first vent steam. The invention further relates to a pressure oxidation arrangement adapted for recovering energy from pressure oxidation flash steam and to a use of high temperature condensate and to a use of a direct contact condenser for recovery of energy and water from a pressure oxidation flash steam.

First claim

1 . A method of recovering energy and water from pressure oxidation flash steam, characterized in that the method comprises a step wherein:
(a) a first flash steam directly obtained from a first flash vessel is contacted with a first recirculating condensate having a first low condensate temperature to condense at least part of the water vapour comprised in the said first flash steam on the first recirculating condensate and simultaneously to heat the said first recirculating condensate to obtain a first recirculating condensate having a first high condensate temperature and a first vent steam.

2 . The method as claimed in claim 1 , wherein the first flash steam is obtained by a step wherein a pressure oxidation discharge slurry obtained directly from a pressure oxidation autoclave is allowed to flash in the first flash vessel to obtain the said first flash steam and a first cooled slurry.

3 . The method as claimed in claim 2 , wherein the pressure oxidation discharge slurry is obtained by pressure oxidation of metal containing ore or concentrate comprising 5 to 40% w/w sulphur as metal sulphides.

4 . The method as claimed in claim 1 , wherein the method further comprises a step wherein:
(b) a second flash steam directly obtained from a second flash vessel is contacted with a second recirculating condensate having a second low condensate temperature to condense at least part of the water vapour comprised in the said second flash steam on the second recirculating condensate and simultaneously to heat the said second recirculating condensate to obtain a second recirculating condensate having a second high condensate temperature and a second vent steam.

5 . The method as claimed in claim 4 , wherein the second flash steam is obtained by a step wherein a first cooled slurry obtained from a first flash vessel is allowed to flash in the second flash vessel to obtain the said second flash steam and a second cooled slurry.

6 . The method as claimed in claim 4 , wherein the method further comprises a step wherein the second flash steam is combined with the first vent steam before it is contacted with a second recirculating condensate in the second condenser.

7 . The method as claimed in claim 1 , wherein step (a) is performed in a first direct contact condenser.

8 . The method as claimed in claim 4 , wherein step (b) is performed in a second direct contact condenser.

9 . The method as claimed in claim 4 , wherein step (b) is performed at atmospheric pressure.

10 . The method as claimed in claim 1 characterized in that the first flash steam is contacted counter currently with the first recirculating condensate.

11 . The method as claimed in claim 4 , wherein the second flash steam is contacted counter currently with the second recirculating condensate.

12 . A pressure oxidation arrangement adapted for recovering energy from pressure oxidation flash steam, characterized in that the arrangement comprises:
a) an autoclave adapted for pressure oxidation of metal containing ore or concentrate; b) a first flash vessel connected to the autoclave for receiving slurry provided by the autoclave and arranged for converting the heat of the slurry into a first flash steam and a first cooled slurry; c) a first condenser connected to the first flash vessel for receiving the flash steam produced in the said first flash vessel and arranged for contacting the first flash steam with a first recirculating condensate having a first low condensate temperature and for condensing at least part of the water vapour comprised in the said flash steam and for raising temperature of the recirculating concentrate to obtain a first recirculating condensate having a first high condensate temperature and a first vent steam.

13 . The pressure oxidation arrangement as claimed in claim 12 , wherein the arrangement further comprises:
d) a second flash and condensing unit i.e. a second flash vessel connected to the first flash vessel for receiving the first cooled slurry and converting the heat of the first cooled slurry into a second flash steam and a second cooled slurry; (e) a second condenser connected to the second flash vessel for receiving the second flash steam and arranged for contacting the second flash steam with a second recirculating condensate having a second low condensate temperature and for condensing at least part of the water vapour comprised in the said second flash steam to obtain a second recirculating condensate having a second high condensate temperature and a second vent steam.

14 . The pressure oxidation arrangement as claimed in claim 13 , wherein the second condenser is further connected to the first condenser for receiving and condensing the first vent steam on the second recirculating condensate.

15 . The pressure oxidation arrangement of claim 13 , wherein the arrangement further comprises one or more further flash and condensing unit(s).

16 . The pressure oxidation arrangement as claimed in claim 13 wherein the condenser is a direct contact condenser.

17 . The pressure oxidation arrangement as claimed in claim 13 wherein arrangement comprises a first condenser vent of the first condenser arranged for controlling the pressure in the first flash vessel and the first condenser.

18 . Use of high temperature condensate obtained by a method claimed in claim 1 as an energy source.

19 . Use of a direct contact condenser for recovery of energy and water from a pressure oxidation flash steam by a method claimed in claim 1 .

Assignees

• Outotec Finland Oy

Inventors

• O'Callaghan John
• Haakana Timo
• Pieviläinen Risto

Classifications

• B01J19/1862

  placed in series · CPC title

• B01J2219/00768

  vertical · CPC title

• B01J19/0066

  Stirrers (mixing per se B01F) · CPC title

• B01J2219/182

  horizontal · CPC title

• B01J19/18

  Stationary reactors having moving elements inside (B01J19/08, B01J19/26 take precedence) · CPC title