Membrane separation process and membrane plant for energy-efficient production of oxygen

Patent metadata

Field	Value
Publication number	US-2016136571-A1
Application number	US-201414904780-A
Country	US
Kind code	A1
Filing date	Jul 15, 2014
Priority date	Jul 17, 2013
Publication date	May 19, 2016
Grant date	—

Abstract

The invention relates to a membrane separation process for energy-efficient generation of oxygen from fresh air. In the process, mixed conducting membranes in vacuum operation are used, the fresh air is discharged as waste air after separation of the oxygen, at least 85% of the thermal energy required for heating the fresh air is acquired by utilizing the waste heat of the waste air and/or of the obtained oxygen, the rest of the heating of the fresh air being realized through external energy supply, and a ratio of fresh air to generated oxygen in normal operation is adjusted to a range of from 6:1 to 25:1.

First claim

1 .- 10 . (canceled)

11 . A membrane separation process for energy-efficient generation of oxygen from fresh air, wherein mixed conducting membranes in vacuum operation are used, the fresh air is discharged as waste air after separation of the oxygen, at least 85° A) of the thermal energy required for heating the fresh air is acquired by utilizing the waste heat of the waste air and/or of the obtained oxygen, the rest of the heating of the fresh air is realized through external energy supply, and a ratio of fresh air to generated oxygen in normal operation is adjusted to a range of from 6:1 to 25:1.

12 . The membrane separation process of claim 11 , wherein the rest of the heating is carried out by electric heating or a combustion process.

13 . The membrane separation process of claim 11 , wherein the thermal energy required for heating the fresh air is obtained through the use of regenerative heat exchangers.

14 . The membrane separation process of claim 11 , wherein the oxygen is removed by vacuum on the permeate side, the feed gas is introduced at ambient pressure, and vacuum generation is carried out through at least one of an electromechanical vacuum pump, a mechanical vacuum pump or a steam jet pump.

15 . The membrane separation process of claim 11 , wherein the air throughput is controlled such that an oxygen partial pressure in the waste air is not higher than 100 mbar above a vacuum pressure on a permeate side.

16 . The membrane separation process of claim 15 , wherein the oxygen partial pressure in the waste air is less than 20 mbar above the vacuum pressure on the permeate side.

17 . The membrane separation process of claim 12 , wherein the air throughput is controlled such that an oxygen partial pressure in the waste air is not higher than 100 mbar above a vacuum pressure on a permeate side.

18 . The membrane separation process of claim 17 , wherein the oxygen partial pressure in the waste air is less than 20 mbar above the vacuum pressure on the permeate side.

19 . The membrane separation process of claim 11 , wherein more than 95% of the thermal energy required for heating the fresh air is acquired by utilizing the waste heat of the waste air and/or of the obtained oxygen.

20 . A membrane plant for energy-efficient production of oxygen from fresh air, wherein
the plant comprises a housing with an input and an output, MIEC membranes and a vacuum pump, a metal connection plate is arranged in the housing, which metal connection plate comprises a vacuum-tight hollow space structure in which the MIEC membranes which are closed on one side are arranged in a gastight manner, at least one dividing wall for dividing into chambers is present, each chamber comprising a stationary regenerator, a supplemental heater and a portion of the MIEC membranes, and an orifice is present in every dividing wall to ensure passage for the fresh air from a chamber downstream of the input to a chamber upstream of the output, an upstream fan is arranged upstream of the input, a downstream fan is arranged downstream of the output, the upstream fan and the downstream fan having opposite suction directions, a regenerative heat exchanger is present, partial regions being associated with the input and other partial regions being associated with the output, and the vacuum pump communicates with the hollow space structure for sucking out the obtained oxygen.

21 . The membrane plant of claim 20 , wherein the housing is not pressure-tight.

22 . The membrane plant of claim 20 , wherein the opposite suction directions are reversibly adjustable.

23 . The membrane plant of claim 20 , wherein the upstream fan and the downstream fan are arranged on a rotary slide such that during rotation of the rotary slide the input moves from the chamber downstream of the input to the respective adjacent chamber and, consequently, the output moves from the opposite chamber to the adjacent chamber.

24 . The membrane plant of claim 23 , wherein the input and, consequently, the output extend over a plurality of adjacent chambers.

25 . The membrane plant of claim 21 , wherein the opposite suction directions are reversibly adjustable.

26 . The membrane plant of claim 21 , wherein the upstream fan and the downstream fan are arranged on a rotary slide such that during rotation of the rotary slide the input moves from the chamber downstream of the input to the respective adjacent chamber and, consequently, the output moves from the opposite chamber to the adjacent chamber.

27 . The membrane plant of claim 26 , wherein the input and, consequently, the output extend over a plurality of adjacent chambers.

Assignees

• Fraunhofer Ges Forschung

Inventors

• Kriegel Ralf

Classifications

• B01D53/22 Primary

  by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00) · CPC title

• B01D2053/223

  with hollow tubes · CPC title

• C01B13/0251

  by making use of membranes · CPC title

• B01D71/02

  Inorganic material · CPC title

• B01D53/228 Primary

  characterised by specific membranes · CPC title