Methods for cleaning industrial equipment with pre-treatment

Abstract

A method of cleaning equipment such as heat exchangers, evaporators, tanks and other industrial equipment using clean-in-place procedures and a pre-treatment solution prior to the conventional CIP cleaning process. The pre-treatment step improves the degree of softening of the soil, and thus facilitates its removal. The pre-treatment solution can be a strong acidic solution, a strong alkaline solution, or comprise a penetrant. A preferred strong acidic solution is an acid peroxide solution. In some embodiments, the pre-treatment may include no strong alkali or acid ingredient; rather, the penetrant provides acceptable levels of pre-treatment.

1 .- 12 . (canceled) 
     
     
         13 . A method for cleaning soil from industrial equipment using a CIP process, the method comprising:
 (a) applying a pre-treatment solution to the soil, the solution comprising at least 0.25 wt % active ingredients, the active ingredients comprising:
 a builder selected from the group consisting of sodium gluconate; a polyphosphate; a phosphonic acid; phosphono-1,2,4-tricarboxylic acid and mixtures thereof; and 
 an oxidizer selected from the group consisting of hydrogen peroxide, peroxycarboxylic acids, and mixtures thereof; and 
   (b) circulating a second solution through the equipment, the second solution comprising a dilute alkaline detergent, wherein there is no rinse step between the application of the pre-treatment solution and the second solution; and   (c) rinsing the equipment.   
     
     
         14 . The method of  claim 13 , wherein the builder is present in an amount of at least about 0.25 wt %. 
     
     
         15 . The method of  claim 14 , wherein the builder is sodium gluconate. 
     
     
         16 . The method of  claim 13 , wherein the oxidizer is present in an amount of about 0.01 wt-% to about 1 wt-%. 
     
     
         17 . The method of  claim 16 , wherein the oxidizer is hydrogen peroxide. 
     
     
         18 . The method of  claim 13 , wherein the pre-treatment solution further comprises about 0.25 wt-% to about 10 wt-% of an organic acid. 
     
     
         19 . The method of  claim 18 , wherein the organic acid is selected from the group consisting of pelargonic acid, methanesulfonic acid, hydroxyethylidene diphosphonic acid, gluconic acid and mixtures thereof. 
     
     
         20 . The method of  claim 19 , wherein the pre-treatment solution further comprises about 0.4 wt-% to about 8.0 wt-% of a penetrant. 
     
     
         21 . The method of  claim 20 , wherein the penetrant comprises an alkyl capped polyoxyethylene glycol ether. 
     
     
         22 . The method of  claim 21 , wherein the pre-treatment solution comprises:
 (a) sodium gluconate;   (b) hydrogen peroxide;   (c) hydroxyethylidene diphosphoic acid;   (d) pelargonic acid; and   (e) n-butyl capped alcohol ethoxylate (5EO).   
     
     
         23 . The method of  claim 22 , wherein the pre-treatment solution further comprises methanesulfonic acid. 
     
     
         24 . The method of  claim 22 , wherein the pre-treatment solution further comprises a mineral acid. 
     
     
         25 . The method of  claim 24 , wherein the mineral acid is phosphoric acid. 
     
     
         26 . A method for cleaning soil from industrial equipment using a CIP process, the method comprising:
 (a) applying a pre-treatment solution to the soil, the solution comprising at least 0.25 wt % active ingredients, the active ingredients comprising:
 an oxidizer selected from the group consisting of hydrogen peroxide, peroxycarboxylic acids, and mixtures thereof; and 
 an acid selected from the group consisting of mineral acids, organic acids, and mixtures thereof; 
   (b) circulating a second solution through the equipment, the second solution comprising a dilute alkaline detergent, wherein there is no rinse step between the application of the pre-treatment solution and the second solution; and   (c) rinsing the equipment.   
     
     
         27 . The method of  claim 26 , wherein the organic acid is selected from the group consisting of gluconic acid, pelargonic acid, methanesulfonic acid, hydroxyethylidene diphosphonic acid, and mixtures thereof. 
     
     
         28 . The method of  claim 27 , wherein the organic acid is gluconic acid. 
     
     
         29 . The method of  claim 27 , wherein the pre-treatment solution further comprises a builder selected from the group consisting of sodium gluconate; a polyphosphate; a phosphonic acid; phosphono-1,2,4-tricarboxylic acid and mixtures thereof. 
     
     
         30 . The method of  claim 29 , wherein the builder is sodium gluconate. 
     
     
         31 . The method of  claim 26 , wherein the mineral acid is phosphoric acid. 
     
     
         32 . The method of  claim 26 , wherein the pretreatment solution further comprises an alkaline source. 
     
     
         33 . The method of  claim 32 , wherein the alkaline source is sodium carbonate. 
     
     
         34 . The method of  claim 32 , wherein the alkaline source is selected from the group consisting of potassium hydroxide, sodium hydroxide, and mixtures thereof. 
     
     
         35 . The method of  claim 34 , wherein the pre-treatment solution further comprises a polyphosphate.