Suspensions of inorganic cleaning agents

Abstract

Methods for on-line cleaning hot parts of a gas turbine during its operation are provided. A cleaning agent composition is injected into a hot gas path of the gas turbine, and includes a liquid carrier and a descaling material suspending in the liquid carrier. The descaling material includes at least one oxide, in an anhydrous or a hydrated form, that is derived from calcium, magnesium, titanium, iron, aluminium, silicon in the form of silicates having non-fibrous structures, or phosphorus in the form of alkaline-earth phosphates. Cleaning agents are also provided for use in a gas turbine.

What is claimed is: 
     
         1 . A method for on-line cleaning hot parts of a gas turbine during operation, the method comprising:
 injecting a cleaning agent composition into a hot gas path of the gas turbine, wherein the cleaning agent composition comprises: a liquid carrier and a descaling material suspending in the liquid carrier,   wherein the descaling material comprises at least one oxide, in an anhydrous or a hydrated form, that is derived from calcium, magnesium, titanium, iron, aluminium, silicon in the form of silicates having non-fibrous structures, or phosphorus in the form of alkaline-earth phosphates.   
     
     
         2 . The method as in  claim 1 , wherein the descaling material has a particle size that is about 5 μm to about 315 μm. 
     
     
         3 . The method as in  claim 1 , wherein the descaling material comprises an iron oxide. 
     
     
         4 . The method as in  claim 1 , wherein the cleaning agent composition comprises at least one descaling material selected from the following inorganics: hematite; maghemite; goethite; lepidocrocite; magnetite; wustite; rutile; anatase; brookite; geikielite; perovskite; ilmenite; wollastonite; larnite; enstatite; akermanite; diopside; merwinite; monticellite; fosterite; fayalite; andradite; andalousite; kyanite; sillimanite; mullite; anorthite; ghelenite; hydroxyapatite; or mixtures thereof. 
     
     
         5 . The method as in  claim 1 , wherein the liquid carrier is water-based. 
     
     
         6 . The method as in  claim 5 , wherein the liquid carrier comprises polyethylene glycol. 
     
     
         7 . The method as in  claim 5 , wherein the liquid carrier further comprises an alcohol, a polyol, a polyethylene-glycol, a polyether, or a mixture thereof. 
     
     
         8 . The method as in  claim 1 , wherein the cleaning agent composition further comprises a dispersing additive. 
     
     
         9 . The method as in  claim 8 , wherein the dispersing additive has an ammonium counter-ion or amine counter-ion. 
     
     
         10 . The method as in  claim 8 , wherein the dispersing additive is an organic, anionic dispersing additive. 
     
     
         11 . The method as in  claim 8 , wherein the dispersing additive comprises a fatty acid amine; a polycarboxylic acid; a polyamide; a polyester; a polyurethane; a copolymerbased on ether or acrylic groups; or a mixture thereof. 
     
     
         12 . The method as in  claim 1 , wherein the cleaning agent composition further comprises a viscosity modifier additive; an anti-foam additive; a biocide additive; an anti-freeze additive; or a mixture thereof. 
     
     
         13 . The method as in  claim 1 , wherein the cleaning agent composition further comprises an organic, non-siliconated anti-foam additive. 
     
     
         14 . The method as in  claim 1 , wherein the cleaning agent composition further comprises an organic biocide additive. 
     
     
         15 . The method as in  claim 1 , wherein the cleaning agent composition is sprayed into the hot gas path via an injector. 
     
     
         16 . The method as in  claim 1 , wherein the oxide has a Mohs hardness that is less than or equal to 7, and an efficiency factor, defined as the product of its density by its Mohs hardness, that is between 12 and 35. 
     
     
         17 . A cleaning agent comprising:
 a liquid carrier; and   a descaling material suspending in the liquid carrier, wherein the descaling material comprises at least one oxide, in an anhydrous or a hydrated form, that is derived from calcium, magnesium, titanium, iron, aluminium, silicon in the form of silicates having non-fibrous structures, or phosphorus in the form of alkaline-earth phosphates, and wherein the descaling material has a sub-millimeter particle size that is about 5 μm to about 315 μm.   
     
     
         18 . The cleaning agent as in  claim 17 , wherein the descaling material has a Mohs hardness that is less than or equal to 7 and the product of its density by its Mohs hardness is between 12 and 35. 
     
     
         19 . The cleaning agent as in  claim 17 , wherein the cleaning agent composition further comprises a dispersing additive. 
     
     
         20 . The cleaning agent as in  claim 17 , wherein the cleaning agent composition further comprises a viscosity modifier additive; an anti-foam additive; a biocide additive; an anti-freeze additive; or a mixture thereof.