Recycle processes with supercritical siloxanes

Patent metadata

Field	Value
Publication number	US-11084964-B2
Application number	US-201716343317-A
Country	US
Kind code	B2
Filing date	Aug 11, 2017
Priority date	Aug 11, 2017
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

The invention provides circular processes using siloxanes as high-temperature heat transfer fluid (HTF), wherein the siloxanes go over from the state of the supercooled liquid into the state of the high-density supercritical fluid by means of heat uptake without a phase transition and energy is then transferred as energy without a phase transition.

First claim

The invention claimed is:

1. A circular process of heat transfer employing siloxanes as a high-temperature heat transfer fluid (HTF), comprising:
transitioning the siloxanes from a state of a supercooled liquid into a state of a high-density supercritical fluid due to heat uptake, and
transferring energy to an energy consumer without a phase transition of the siloxanes.

2. The circular process of claim 1 , wherein the siloxanes are cooled in the state of the supercritical liquid and in the cooling process transfer heat to an energy consumer.

3. The circular process of claim 1 , wherein the siloxanes in the state of the supercritical liquid are firstly depressurized to below their critical pressure in order to generate mechanical work directly and only then are cooled and condensed in order to transfer heat to an energy consumer.

4. The circular process of claim 1 , wherein the siloxanes used as the HTF comprise methylpolysiloxanes.

5. The circular process of claim 4 , wherein the siloxanes used as the HTF are mixtures of linear methylpolysiloxanes of the formula I
Me 3 SiO—(Me 2 SiO) x —SiMe 3   (I),

and cyclic compounds of the formula II
(Me 2 SiO) y   (II),

Where
Me is a methyl radical,
x has values of greater than or equal to zero and the arithmetic mean of x weighted according to the molar proportions over all linear methylpolysiloxanes is in the range of from 3 to 20 and
y has values greater than or equal to 3 and the arithmetic mean of y weighted according to the molar proportions over all cyclic methylpolysiloxanes is in the range of from 3 to 6.

6. The circular process of claim 1 , wherein the siloxanes used as the HTF are branched compounds of the formula III
(Me 3 SiO 1/2 ) w (SiO 4/2 ) z   (III)

Where

w is an integer from 4 to 20,
z is an integer from 1 to 15 and
Me is a methyl radical.

Assignees

• Wacker Chemie Ag

Inventors

• Voit Harald
• Dörrich Steffen
• Petri Martin
• Schaffer Erich
• Weidner Richard

Classifications

• F22B1/006

  using solar heat · CPC title

• F01K25/08

  using special vapours · CPC title

• F01K7/22

  the turbines having inter-stage steam heating · CPC title

• C09K5/10 Primary

  Liquid materials · CPC title

• C07F7/0838

  Compounds with one or more Si-O-Si sequences (compounds with a ring containing only alternating Si and O atoms, i.e. cyclosilanes C07F7/21) · CPC title