Methods for reducing the corrosiveness of a fluid material for a high-temperature range and devices therefore

Patent metadata

Field	Value
Publication number	US-2019376192-A1
Application number	US-201816003229-A
Country	US
Kind code	A1
Filing date	Jun 8, 2018
Priority date	Jun 8, 2018
Publication date	Dec 12, 2019
Grant date	—

Abstract

The present application refers to a method for the reduction of the corrosiveness of a heat storage or heat transfer fluid material for the high-temperature range and a device for said method. The respective heat storage or heat transfer fluid material obtained by the method may be used in solar thermal power plants, conventional fossil power plants with higher flexibility, pumped thermal energy storage, combined heat and power plants, intermediate storage of high-temperature process heat, or in sensible heat storage with molten salts.

First claim

1 . A method comprising:
providing an electrochemical system comprising an anode and a cathode and a molten salt containing at least one oxygen impurity;
exposing the molten salt to a voltage;
contacting the cathode and the anode physically and electrically with the molten salt; and
removing at least a portion of the at least one oxygen impurity.

2 . The method of claim 1 , wherein the molten salt comprises a halogen salt.

3 . The method of claim 2 , wherein the halogen salt comprises a chloride salt.

4 . The method of claim 2 , wherein:
the halogen salt comprises a cation, and the cation comprises at least one of Mg, Ca, Na, K, Li, Sr, Ba, Zn, Al, Sn, Fe, Cr, Mn, or Ni.

5 . The method of claim 1 , wherein the exposing is performed at a temperature between 300° C. and 800° C.

6 . The method of claim 1 , wherein the exposing is performed in an inert atmosphere.

7 . The method according to claim 1 , wherein the material for an anode in the electrochemical process is selected from an alkali metal, e.g. Li, Na, K, an alkaline earth metal (e.g. Mg, Ca, Sr, Ba), a transition metal (e.g. Co, Ni, Fe, Zn), or a metalloid (e.g. B or Si).

8 . The method according to claim 1 , wherein the material for an anode in the electrochemical process is an alkaline earth metal such as Mg.

9 . The method according to claim 1 , wherein the material for the reference electrode for the electrochemical process is selected from tungsten, silver, gold, platinum, palladium, or nickel-alloys.

10 . The method according to claim 1 , wherein the cathode is solid or liquid at the temperature at which the electrochemical process takes place.

11 . The method according to claim 1 , wherein the material for the cathode is selected from tungsten, silver, gold, platinum, palladium, or nickel-alloys.

12 . The method according to claim 1 , wherein the construction material of a container in which the electrochemical reaction takes place acts as cathode.

13 . The method according to claim 12 , wherein the construction material is selected from 1.44xx, 1.45xx, 1.78xx, or 2.xxxx alloys.

14 . The method according to claim 1 , wherein over-potential is applied periodically or constant.

15 . The method according to claim 1 , wherein the molten salt is purified prior to feeding it into a tank.

16 . The method according to claim 1 , wherein the molten salt is purified during operation inside a storage tank.

17 . The method according to claim 1 , wherein the molten salt is purified when flowing in or out of a storage tank.

18 . The method according to claim 1 , further comprising purification in a flow of the molten halogen salt.

19 . The method according to claim 1 , further comprising controlling the effort of the electrochemical process.

20 . The method according to claim 19 , wherein the control is done via cyclic voltammetry measurement.

21 . The method according to claim 19 wherein the control is done in situ.

22 . A device for the purification of molten halogen salts as high-temperature heat storage or heat transfer fluid material comprising at least one cyclic voltammetry measurement (CVM) device and at least one electrochemical purification (ECP) device, said electrochemical purification device comprises an anode, a cathode, and a reference electrode.

23 . The device according to claim 22 further comprising two CVM devices, wherein the first CVM device is located on one side of the ECP device and the second CVM device is located on the opposite side of the ECP device.

24 . The device according to claim 22 , further comprising a gravimetric drainage.

25 . The device according to claim 22 , further comprising one or more of a heat exchanger, a temperature control unit, and/or a cold trap for molten salt.

26 . The device according to claim 22 , wherein the electrodes of the ECP are in the form of rods, plates, meshes, or perforated plates.

Assignees

• Deutsch Zentr Luft & Raumfahrt
• Alliance Sustainable Energy

Inventors

• Ding Wenjin
• Bauer Thomas
• Vidal Judith Cecilia

Classifications

• C25B15/02

  Process control or regulation · CPC title

• C25B1/14

  Alkali metal compounds · CPC title

• C25B1/24 Primary

  Halogens or compounds thereof · CPC title

• F03G6/02

  using a single state working fluid · CPC title

• F24S60/00

  Arrangements for storing heat collected by solar heat collectors (working fluids forming pools or ponds F24S10/10) · CPC title