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.