Process for producing an element for absorbing solar radiation for a thermal concentrating solar power plant

Patent metadata

Field	Value
Publication number	US-9551507-B2
Application number	US-201214122422-A
Country	US
Kind code	B2
Filing date	Jun 7, 2012
Priority date	Jun 9, 2011
Publication date	Jan 24, 2017
Grant date	Jan 24, 2017

Abstract

A solar radiation absorber element for a thermal concentrating solar power plant is achieved by forming a selective coating on an outer surface of a substrate made from stainless steel, chosen from stainless steels presenting an aluminum content of more than 0.5% by weight. Formation of the selective coating includes a surface treatment step of the substrate, by polishing, and a heat treatment step of the substrate, in an oxidizing atmosphere, in a temperature range included between 550° C. and 650° C. The heat treatment in particular enables at least one intrinsically selective superficial thin layer to be formed on the outer surface of the substrate.

First claim

The invention claimed is:

1. A method for producing a solar radiation absorber element, for a thermal concentrating solar power plant, comprising formation of a selective coating on an outer surface of a stainless steel substrate,
wherein the formation of the selective coating comprises the following successive steps:
surface treatment by polishing of the stainless steel substrate,
and heat treatment of the stainless steel substrate, in an oxidizing atmosphere containing at least 5% in volume of an oxygen precursor, in a temperature range comprised between 550° C. and 650° C., to form on the outer surface of the stainless steel substrate at least one intrinsically selective superficial thin layer having a thickness of more than 70 nm so as to be intrinsically selective,

and wherein the stainless steel of the substrate presents an aluminum content of more than 0.5% by weight.

2. The method according to claim 1 , wherein the stainless steel of the substrate is chosen from stainless steels presenting a chromium content comprised between 15% by weight and 25% by weight.

3. The method according to claim 2 , wherein the stainless steel of the substrate is chosen from stainless steels presenting a chromium content comprised between 20% by weight and 22% by weight.

4. The method according to claim 2 , wherein the stainless steel of the substrate presents an aluminum content comprised between 4% by weight and 6% by weight.

5. The method according to claim 4 , wherein the stainless steel of the substrate is a steel of FeCrAl type.

6. The method according to claim 1 , wherein the stainless steel of the substrate is a ferritic stainless steel.

7. The method according to claim 6 , wherein the stainless steel of the substrate is chosen from ferritic stainless steels respectively designated by the symbols X10CrAlSi13, X10CrAlSi18, X10CrAlSi25, X3CrAlTi18-2 and X10CrAlSi7.

8. The method according to claim 1 , wherein the stainless steel of the substrate is an austenitic stainless steel.

9. The method according to claim 1 , wherein the intrinsically selective superficial thin layer has a thickness comprised between 100 nm and 1000 nm.

10. The method according to claim 1 , wherein the roughness of the outer surface of the stainless steel substrate, after polishing, is comprised between 0.05 μm and 0.4 μm.

11. The method according to claim 1 , wherein the formation of the selective coating comprises a step of formation of an anti-reflective layer on the intrinsically selective superficial thin layer.

12. The method according to claim 1 , wherein the oxygen precursor is O 2 or water.

13. A method for producing a thermal concentrating solar power plant comprising the following steps:
providing a stainless steel substrate having an outer surface covered by a coating selective to solar radiation, the stainless steel substrate being designed to have a heat exchange fluid flowing through it,
providing a mirror arranged to concentrate a part of the solar radiation received on the stainless steel substrate,

said method comprising the following steps:
providing a stainless steel substrate having an aluminum content of more than 0.5% by weight,
polishing the outer surface of the substrate,
forming an oxide on the polished outer surface of the stainless steel substrate by means of heat treatment comprised between 550° C. and 650° C. in an oxidizing atmosphere, containing at least 5% in volume of an oxygen precursor, so that the oxide is intrinsically selective to solar radiation.

14. The method according to claim 13 , wherein the oxygen precursor is O 2 or water.

15. The method according to claim 13 , further comprising forming an anti-reflective layer on the oxide.

Assignees

• Fleury Gatien
• Couturier Raphaël
• Dubarry Christophe
• Mollard Carole
• Sicardy Olivier
• Commissariat à l'Energie Atomique et aux Energies Alternatives

Inventors

• Fleury Gatien
• Couturier Raphaël
• Dubarry Christophe
• Mollard Carole
• Sicardy Olivier

Classifications

• F24S20/20

  Solar heat collectors for receiving concentrated solar energy, e.g. receivers for solar power plants · CPC title

• C23C8/02

  Pretreatment of the material to be coated (C23C8/04 takes precedence) · CPC title

• C23C8/10

  Oxidising · CPC title

• F24S70/30 Primary

  Auxiliary coatings, e.g. anti-reflective coatings · CPC title

• C23C8/18

  Oxidising of ferrous surfaces · CPC title