Bearing Lubricants For Pulverizing Equipment

Abstract

The invention relates to a method of lubricating the bearings of solid fuel pulverizers, for example, coal pulverizers. The method involves supplying to the bearings a lubricating composition designed to have superior performance compared to conventional coal pulverizer bearing lubricants. The invention also provides a bearing lubricant for a coal pulverizer as well as its use in coal pulverizing equipment to improve the service life and/or durability of bearings in coal pulverizing equipment. The invention also provides an additive composition for use in a bearing lubricant for a coal pulverizer, as well as the use of the additive composition to improve the service life and/or performance of the bearing lubricant.

What is claimed is: 
     
         1 . A method of lubricating the bearings of a solid fuel pulverizer comprising the steps of:
 I. supplying to said bearings a lubricant composition comprising:
 (a) an oil of lubricating viscosity; 
 (b) a phosphorus-containing compound; and 
 (c) a nitrogen-containing dispersant; 
   and wherein the lubricant composition optionally further comprises:
 (d) a sulfur-containing compound. 
   
     
     
         2 . The method of  claim 1  wherein the oil of lubricating viscosity comprises a mineral base oil. 
     
     
         3 . The method of  claim 2  wherein the oil of lubricating viscosity comprises a synthetic base oil. 
     
     
         4 . The method of  claim 1  wherein the phosphorus-containing compound comprises an alkyl phosphite, a phosphoric acid ester, an amine salt of a phosphoric acid ester, or some combination thereof. 
     
     
         5 . The method of  claim 1  wherein the nitrogen-containing dispersant comprises: a polyetheramine; a borated succinimide dispersant; a non-borated succinimide dispersant; a Mannich dispersant comprising the reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol; or any combination thereof. 
     
     
         6 . The method of  claim 5  wherein the nitrogen-containing dispersant comprises a non-borated succinimide dispersant derived from an aromatic amine. 
     
     
         7 . The method of  claim 1  wherein the lubricant composition further comprises: (d) a sulfur-containing compound. 
     
     
         8 . The method of  claim 1  wherein the phosphorus-containing compound comprises an alkyl phosphite and the nitrogen-containing dispersant comprises a non-borated succinimide dispersant. 
     
     
         9 . The method of  claim 1  wherein the phosphorus-containing compound is present in the lubricant composition from 0.01 to 5.0 percent by weight; and
 wherein the nitrogen-containing dispersant is present in the lubricant composition from 0.01 to 4.0 percent by weight. 
 
     
     
         10 . A bearing lubricant for a solid fuel pulverizer comprising:
 (a) an oil of lubricating viscosity;   (b) a phosphorus-containing compound; and   (c) a nitrogen-containing dispersant.   
     
     
         11 . The bearing lubricant of  claim 10  wherein the phosphorus-containing compound comprises an alkyl phosphite, a phosphoric acid ester, an amine salt of a phosphoric acid ester, or some combination thereof. 
     
     
         12 . The bearing lubricant of  claim 10  wherein the nitrogen-containing dispersant comprises: a polyetheramine; a borated succinimide dispersant; a non-borated succinimide dispersant; a Mannich dispersant comprising the reaction product of a dialkylamine, an aldehyde and a hydrocarbyl substituted phenol; or any combination thereof. 
     
     
         13 . The bearing lubricant of  claim 10  wherein the phosphorus-containing compound is present in the lubricant composition from 0.01 to 5.0 percent by weight; and
 wherein the nitrogen-containing dispersant is present in the lubricant composition from 0.01 to 4.0 percent by weight. 
 
     
     
         14 . The bearing lubricant of  claim 10  wherein the bearing lubricant further comprises: (d) a sulfur-containing compound. 
     
     
         15 . The use of a lubricant composition to improve the service life or durability of bearings in solid fuel pulverizing equipment, said lubricant composition comprising:
 (a) an oil of lubricating viscosity;   (b) a phosphorus-containing compound; and   (c) a nitrogen-containing dispersant.