Method for cleaning industrial equipment with pre-treatment
View Patent ↗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. A method of cleaning soils from industrial equipment using a CIP process, the method comprising:
(a) applying a liquid acidic pre-treatment solution to the soil, the solution comprising at least 0.25 wt-% active ingredients, the active ingredients comprising:
a surfactant penetrant comprising a C 6 -C 12 fatty acid;
and an oxidizer selected from the group consisting of hydrogen peroxide, peroxycarboxylic acid compounds and mixtures thereof;
(b) allowing the pretreatment solution to remain on the soil for a period of time sufficient to facilitate soil removal;
(c) circulating a liquid CIP solution through the equipment after the pre-treatment solution, the CIP solution comprising about 0.5 to 3% of a dilute alkaline detergent wherein there is not a rinse step between the pre-treatment solution and the CIP solution; and then
(c) rinsing the equipment.
2. The method according to claim 1 , wherein the pre-treatment solution further comprises 0.25 to 1.5 wt-% acid.
3. The method according to claim 2 , wherein the pre-treatment solution comprises 0.25 to 1.5 wt-% acid and 0.4 to 8 wt-% penetrant.
4. The method according to claim 2 , wherein the pre-treatment solution comprises:
(a) 0.25 to 1.5 wt-% acid, selected from the group consisting of phosphoric acid, nitric acid, sulfuric acid, lactic acid, acetic acid, hydroxyacetic acid citric acid, and mixtures thereof; and
(b) 0.01 to 1 wt-% oxidizer comprising a peroxycarboxylic acid.
5. The method according to claim 1 , wherein the oxidizer is present at a level of 0.05 to 0.5 wt-%.