Methods for hydrogen gas production

• US 9,546,426 B2
• Filed: 03/07/2014
• Issued: 01/17/2017
• Est. Priority Date: 03/07/2013
• Status: Active Grant

• Current Assignee: Penn State Research Foundation (Pennsylvania State University)
• Original Assignee: Penn State Research Foundation (Pennsylvania State University)
• Inventors: Logan, Bruce E., Kim, Younggy, Cusick, Roland D.
• Primary Examiner(s): Smith, Nicholas A
• Application Number:
  US14/200,922
• Publication Number:
  US 20140251819A1
• Time in Patent Office: 1,047 Days
• US Class Current: 1/1
• CPC Class Codes: C25B 1/02 Hydrogen or oxygen
• CPC Class Codes: C25B 1/04 by electrolysis of water
• CPC Class Codes: C25B 15/08 Supplying or removing reactants or electrolytes; Regeneration of electrolytes
• CPC Class Codes: C25B 9/19 with diaphragms
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y02P 20/129 Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines

Abstract

According to aspects described herein, methods and systems provided by the present invention for hydrogen gas production include a RED stack including one or more RED subunits, and use of a saline material including a heat regenerable salt. The salinity driven energy, provided by the one or more RED subunits, completely eliminates the need for an external power source to produce hydrogen gas.

Claims

1. A process for generating a hydrogen gas, comprising:

introducing, in a system comprising;

a reaction chamber having a wall defining an interior of the reaction chamber and an exterior of the reaction chamber, an anode at least partially contained within an anode compartment of the reaction chamber, a cathode at least partially contained within a cathode compartment of the reaction chamber, a conductive conduit for electrons in electrical communication with the anode and the cathode, a plurality of alternating anion-selective barriers and cation-selective barriers disposed between the anode and the cathode and defining alternating saline material compartments and lower-saline material compartments, a first flow path for a saline material through the saline material compartments and a second flow path for a lower-saline material through the lower-saline material compartments, wherein the saline material and the lower-saline material are adjacent and separated by the anion selective barriers and the cation selective barriers, a saline material having a concentration of dissolved salts into the saline material compartments; and

introducing a lower-saline material having a concentration of dissolved salts which is lower than the saline material into the lower-saline material compartments, wherein an electromotive force established by a difference in the concentration of dissolved salts in the saline material compared to the lower-saline material, drives ions across the plurality of alternating anion-selective barriers and cation-selective barriers disposed between the anode and the cathode, thereby increasing the potential between the anode and cathode, decreasing the concentration of dissolved salts in the saline material to generate a saline material effluent, and increasing the concentration of dissolved salts in the lower-saline material to generate a lower-saline material effluent;

treating the lower-saline material effluent by;

heating the lower-saline material effluent to volatilize and remove a dissolved heat regenerable salt, thereby producing a regenerated lower-saline material, or combining the lower-saline material effluent and saline material effluent, thereby producing a regenerated saline material, respectively; and

introducing the regenerated lower-saline material into the lower-saline material compartments or introducing the regenerated saline material into the saline material compartments.

2. The process of claim 1, wherein a saline ratio between the saline material and the lower-saline material introduced into the saline material compartment and lower-saline material compartment is greater than 1:

1.

3. The process of claim 1, wherein the saline material comprises a heat regenerable salt.

4. The process of claim 1, wherein the dissolved heat regenerable salt is selected from the group consisting of:

ammonium bicarbonate, ammonium hydroxide and a combination thereof.

5. The process of claim 3, wherein the saline material comprises one or more dissolved non-heat regenerable salts, wherein the total concentration of dissolved heat regenerable salt is greater than the total concentration of the one or more dissolved non-heat regenerable salts.

6. The process of claim 1, wherein the heating comprises heating with waste heat from a second process, heat generated by a solar heater or solar collector or a combination of waste heat from a second process and heat generated by a solar heater or solar collector.

7. The process of claim 1, wherein, each lower-saline material compartment is in fluid communication with each other lower-saline material compartment, wherein each saline material compartment is in fluid communication with each other saline material compartment.

8. The process of claim 7, wherein saline material flows sequentially through each saline material compartment, wherein lower-saline material flows sequentially through each lower-saline material compartment, and wherein the saline material and lower-saline material flow in a counter-current direction or co-current direction with respect to each other.

9. The process of claim 1, wherein the saline material is a brine solution from a reverse osmosis plant and the lower-saline material is a saline seawater stream.

10. The process of claim 1, wherein the cathode compartment contains a catholyte, the catholyte including a heat regenerable salt.

11. The process of claim 1, wherein the heat regenerable salt is present in a concentration in the range of 0.001M-1M.

12. The process of claim 1, wherein the system further comprises:

a conduit for transport of a lower-saline material effluent from the lower-saline material compartment to a container having a first liquid containing portion adjacent a heat source, a vapor condenser portion and a second liquid containing portion for containing condensed vapor;

a conduit for transport of a regenerated lower-saline material from the second liquid containing portion for containing condensed vapor to a lower-saline material compartment.

13. The process of claim 1, wherein the system further comprises:

a conduit for transport of a lower-saline material effluent from the lower-saline material compartment to a container having a first liquid containing portion adjacent a heat source, a vapor distillation membrane and a second liquid containing portion for containing liquid condensed from vapor which passes through the distillation membrane; and

a conduit for transport of a regenerated saline material from the first liquid containing portion to a saline material compartment.

14. The process of claim 12, wherein each lower-saline material compartment is in fluid communication with each other lower-saline material compartment and wherein each saline material compartment is in fluid communication with each other saline material compartment.

15. The process of claim 1, wherein the cathode compartment is a saline material compartment.

16. The process of claim 1, further comprising a bipolar membrane disposed adjacent the anode compartment.

17. The process of claim 1, further comprising a lower-saline compartment adjacent the anode compartment.

18. The process of claim 16, wherein a bipolar membrane disposed adjacent the anode compartment is disposed between the anode compartment and the lower-saline compartment adjacent the anode compartment.