Method and apparatus for operating a steam cycle process with a lubricated expander

Patent metadata

Field	Value
Publication number	US-9382816-B2
Application number	US-201113701378-A
Country	US
Kind code	B2
Filing date	May 24, 2011
Priority date	Jun 1, 2010
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

Embodiments of the invention relate to a method for operating a steam cycle process performed in an apparatus having an evaporator or steam generator for the evaporation of a liquid working medium and an expander, which is lubricated by a lubricant, for the performance of mechanical work. The method comprises a) supplying the liquid working medium to the evaporator, in which it evaporates and is fed to the expander in the form of steam; b) supplying an ionic liquid, which at room temperature forms two liquid phases with the liquid working medium, to the expander as a lubricant; and c) separating the ionic liquid forming the lubricant for the expander from the working medium upstream of the evaporator.

First claim

The invention claimed is:

1. A method for operating a steam cycle process using an apparatus including an evaporator or vapor generator for evaporating a liquid working medium and an expander lubricated by a lubricant, for performing mechanical work, the method comprising:
a) supplying the liquid working medium to the evaporator, in which the liquid working medium is evaporated, and supplying in vapor form the evaporated liquid medium from the evaporator to the expander;
b) supplying, as lubricant, an ionic liquid which forms two liquid phases with the liquid working medium at room temperature, to the expander; and
c) separating the ionic liquid from the working medium upstream of the evaporator,
wherein the solubility of the ionic liquid in the working medium is <0.1 m%, and/or the solubility of the working medium in the ionic lubricant is <1 m%.

2. The method as claimed in claim 1 , further comprising:
supplying the ionic liquid to the vaporous working medium upstream of the expander, together with the working medium, and/or
metering the ionic liquid into the expander.

3. The method as claimed in claim 1 , further comprising:
supplying the vaporous working medium to at least one condenser in which the vaporous working medium is liquefied, before returning the vaporous working medium to the evaporator.

4. The method as claimed in claim 1 , comprising separating the ionic liquid from the vaporous working medium, downstream of the expander, in a single-stage or multi-stage process.

5. The method as claimed in claim 1 , comprising:
conducting the ionic liquid in a lubricant circuit including at least one reservoir;
extracting the ionic liquid from the at least one lubricant reservoir;
supplying the extracted ionic liquid to the expander; and
returning the ionic liquid to the at least one lubricant reservoir from the expander.

6. The method as claimed in claim 1 , wherein the apparatus implementing the steam cycle process is part of a motor vehicle, the method further comprising:
supplying waste heat of the motor vehicle to the evaporator; and
using the mechanical work performed by the expander in the motor vehicle.

7. The method as claimed in claim 1 , wherein the working medium comprises water vapor or a volatile substance.

8. The method as claimed in claim 1 , wherein, the ionic liquid, comprises 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1-ethyl-3-methylimidazolium tris(perfluoroalkyl)trifluorophosphate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium methane sulfonate, 1-ethyl-3-methylimidazolium diethyl phosphate, 1-ethyl-3-methylimidazolium dibutyl phosphate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium perfluoroalkyl sulfonate, 1-ethyl-3-methylimidazolium perfluoroalkyl carboxylate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium tricyanomethide, 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-propyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1-propyl-3-methylimidazolium tris(perfluoroalkyl)trifluorophosphate, 1-propyl-3-methylimidazolium ethyl sulfate, 1-propyl-3-methylimidazolium methyl sulfate, 1-propyl-3-methylimidazolium methane sulfonate, 1-propyl-3-methylimidazolium diethyl phosphate, 1-propyl-3-methylimidazolium dibutyl phosphate, 1-propyl-3-methylimidazolium perfluoroalkyl sulfonate, 1-propyl-3-methylimidazolium perfluoroalkyl carboxylate, 1-propyl-3-methylimidazolium dicyanamide, 1-propyl-3-methylimidazolium thiocyanate, 1-propyl-3-methylimidazolium tricyanomethide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1-butyl-3-methylimidazolium tris(perfluoroalkyl)trifluorophosphate, 1-butyl-3-methylimidazolium ethyl sulfate, 1-butyl-3-methylimidazolium methyl sulfate, 1-butyl-3-methylimidazolium methane sulfonate, 1-butyl-3-methylimidazolium diethyl phosphate, 1-butyl-3-methylimidazolium dibutyl phosphate, 1-butyl-3-methylimidazolium perfluoroalkyl sulfonate, 1-butyl-3-methylimidazolium perfluoroalkyl carboxylate, 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium thiocyanate, 1-butyl-3-methylimidazolium tricyanomethide, 1-ethyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide or 1-ethyl-1-methylpyrrolidinium tris (pentafluoroethyl)trifluorophosphate, 1-ethyl-1-methylpyrrolidinium tris(perfluoroalkyl)trifluorophosphate, 1-ethyl-1-methylpyrrolidinium ethyl sulfate, 1-ethyl-1-methylpyrrolidinium methyl sulfate, 1-ethyl-1-methylpyrrolidinium methane sulfonate, 1-ethyl-1-methylpyrrolidinium diethyl phosphate, 1-ethyl-1-methylpyrrolidinium dibutyl phosphate, 1-ethyl-1-methylpyrrolidinium dicyanamide, 1-ethyl-1-methylpyrrolidinium perfluoroalkyl sulfonate, 1-ethyl-1-methylpyrrolidinium perfluoroalkyl carboxylate, 1-ethyl-1-methylpyrrolidinium thiocyanate, 1-ethyl-1-methylpyrrolidinium tricyanomethide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide or 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, 1-butyl-1-methylpyrrolidinium tris(perfluoroalkyl)trifluorophosphate, 1-butyl-1-methylpyrrolidinium ethyl sulfate, 1-butyl-1-methylpyrrolidinium methyl sulfate, 1-butyl-1-methylpyrrolidinium methane sulfonate, 1-butyl-1-methylpyrrolidinium diethyl phosphate, 1-butyl-1-methylpyrrolidinium dibutyl phosphate, 1-butyl-1-methylpyrrolidinium dicyanamide, 1-butyl-1-methylpyrrolidinium perfluoroalkyl sulfonate, 1-butyl-1-methylpyrrolidinium perfluoroalkyl carboxylate, 1-butyl-1-methylpyrrolidinium thiocyanate, 1-butyl-1-methylpyrrolidinium tricyanomethide, tetraalkylammonium bis(trifluoromethylsulfonyl)imide, tetraalkylammonium tris(pentafluoroethyl)trifluorophosphate, tetraalkylammonium tris(perfluoroalkyl)trifluorophosphate, tetraalkylammonium ethyl sulfate, tetraalkylammonium methyl sulfate, tetraalkylammonium methane sulfonate, tetraalkylammonium diethyl phosphate, tetraalkylammonium dibutyl phosphate, tetraalkylammonium dicyanamide, tetraalkylammonium perfluoroalkyl sulfonate, tetraalkylammonium perfluoroalkyl carboxylate, tetraalkylammonium thiocyanate, tetraalkylammonium tricyanomethide, or an ionic liquid which has fluorinated anions and/or cations with one or more medium-length alkyl chains or an ionic liquid which has small, polar anions and/or cations which comprise oxygen atoms and which have one or more short, possibly oxygen-substituted alkyl chains, or a mixture of said ionic liquids.

9. The method as claimed in claim 1 , wherein the solubility of the ionic lubricant in the working medium is chosen from the group consisting of <100ppm, <10 ppm, and <1 ppm.

10. The method as claimed in claim 1 , wherein the solubility of the working medium in the ionic lubricant is <0.1 m%.

11. The method as claimed in claim 4 , comprising:
separating the ionic liquid from the vaporous working medium in a single-stage or multi-stage separator, wherein the condenser is arranged downstream of the expander and upstream of the separator; and
supplying the mixture of working medium and ionic liquid exiting the expander to the condenser.

12. The method as claimed in claim 4 , wherein the working medium exits the expander in vapor form, and the condenser is arranged downstream of the separator in the working medium circuit, the method further comprising, after said separating:
supplying at least partially vaporous working medium to the condenser.

13. The method as claimed in claim 4 , wherein a lubricant reservoir is formed by at least one single or multi-stage separator downstre

Assignees

• Almbauer Raimund
• Kalb Roland
• Kirchberger Roland
• Klammer Josef
• Man Truck & Bus Ag

Inventors

• Almbauer Raimund
• Kalb Roland
• Kirchberger Roland
• Klammer Josef

Classifications

• C10N2020/103

  Containing Hydrocarbons · CPC title

• C10M2215/224

  Imidazoles · CPC title

• F01K23/065

  the combustion taking place in an internal combustion piston engine, e.g. a diesel engine · CPC title

• C10M2219/06

  Thio-acids; Thiocyanates; Derivatives thereof · CPC title

• C10M171/00 Primary

  Lubricating compositions characterised by purely physical criteria, e.g. containing as base-material, thickener or additive, ingredients which are characterised exclusively by their numerically specified physical properties, i.e. containing ingredients which are physically well-defined but for which the chemical nature is either unspecified or only very vaguely indicated (chemically defined ingredients C10M101/00 - C10M169/00; petroleum fractions C10M101/02, C10M121/02, C10M159/04) · CPC title