Colloid systems and wetting agents; subcombinations thereof; pro – Continuous liquid or supercritical phase: colloid systems;... – Aqueous continuous liquid phase and discontinuous phase...
Reexamination Certificate
2000-03-29
2003-03-18
Metzmaier, Daniel S. (Department: 1712)
Colloid systems and wetting agents; subcombinations thereof; pro
Continuous liquid or supercritical phase: colloid systems;...
Aqueous continuous liquid phase and discontinuous phase...
C516S126000, C516S132000, C516S133000, C516S134000, C162S158000, C162S179000
Reexamination Certificate
active
06534550
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to foam control compositions, their preparation and use in aqueous media. Specifically, the invention relates to a defoamer composition particularly useful in controlling foam problems encountered in low to moderate temperature pulp and paper mill process and effluent water streams.
2. Discussion of Background Information
Many waste treatment systems and industrial processes have problems caused by foam that forms as the wastewater or process water flows through the system or process. Foam can occur in any aqueous stream that contains contaminants or additives that lower the surface tension of the stream. These materials are typically organic chemicals. They may be derived from natural chemicals (e.g., lignin, humic acid, tannin), waste chemicals, water treatment chemicals, process treatment chemicals, detergents, cleaners, products or byproducts of industrial processes, microbiological byproducts, etc. The system may also contain other materials that stabilize the foam after it has formed. Such materials include polymers, surfactants, suspended organic and inorganic solids, colloidal material, proteins, and microbiological organisms.
Foam problems frequently occur when a wastewater or process water stream is subjected to a unit operation that increases the total area of the system's gas/liquid interfaces. Such an increase occurs whenever a liquid is broken up into droplets or a gas is introduced into a liquid. Processes causing these effects include: mechanical processes (e.g., agitation, mixing, turbulent flow, pumping, aeration, gasification, reduction in pressure, increase in temperature), biological processes (e.g., fermentation, anaerobic digestion), and chemical processes (e.g., oxidation, recarbonation, gasification, distillation, solvent stripping, and reactions generating gas).
Foam in wastewater or process water is a problem for several reasons and can be detrimental to system processes (e.g., pumping, mixing, distillation, chemical reaction, heat transfer, evaporation, sedimentation, etc.). Foam can interfere with system sensors and controllers (e.g., level controllers, pH sensors, temperature sensors) and can adversely affect the quality and throughput of a product (e.g., holes in paper, and poor adhesion of coatings). Foam can also be a safety or health hazard (e.g., airborne bacteria, and tank overflows) or can also be an aesthetic problem, (e.g., foamy discharge to receiving streams).
The pulp and paper industry experiences some of the most troublesome foam problems because of the ubiquitous presence of lignins and other foam-causing materials. Foaming frequently occurs in pulp washing, pulp screening, pulp bleaching, and waste treatment processes. In addition to the visible foam that occurs on the surface of process and effluent streams, foam may also occur below the surface in the form of entrained air bubbles, particularly in aqueous streams that contain fibers and other particulates. Air bubbles become entrained when they cannot rise to the surface by normal buoyant forces because they are adsorbed to the particulate materials in the stream or their motion is impeded by the presence of the particulates. Entrained air bubbles are a problem because they inhibit the drainage of the washing liquor through the fiber mat which in turn slows down production. Entrained air bubbles are also known to impair paper formation and tensile strength.
SUMMARY OF THE INVENTION
The invention relates to defoaming agent compositions for controlling foam, i.e., defoaming or inhibiting the formation of foam, in aqueous environments, particularly in wastewater systems and aqueous industrial process systems.
The invention also relates to methods for controlling foam, i.e., defoaming or inhibiting the formation thereof, in aqueous environments, particularly in wastewater systems and in aqueous industrial process systems by adding to the system an effective amount of defoaming components, such as by adding the defoaming agent composition of the present invention.
In one aspect, the invention is directed to a method of at least one of defoaming an aqueous system and inhibiting the formation of foam in an aqueous system comprising adding to the aqueous system an effective amount of primary alcohol component that is solid at 25° C., alcohol alkoxylate component and emulsifier component to at least one of defoam the aqueous system and inhibit formation of foam in the aqueous system.
In another aspect, the present invention is directed to a stable defoamer composition comprising primary alcohol component that is solid at 25° C., alcohol alkoxylate component, emulsifier component and water.
The primary alcohol component can comprise at least one linear primary alcohol, and the at least one linear primary alcohol can comprise mixtures of primary linear alcohols. The mixture of primary linear alcohols can comprise C
14
to C
32
primary linear alcohols, more preferably C
18
to C
32
primary linear alcohols, and even more preferably C
18
to C
30
primary linear alcohols. Preferably, at least about 35 percent of the primary linear alcohols comprise C
20
to C
26
primary linear alcohols, more preferably at least about 70 percent of the primary linear alcohols comprise C
20
to C
26
primary linear alcohols, and even more preferably at least about 80 percent of the primary linear alcohols comprise C
20
to C
26
primary linear alcohols.
The primary alcohol component can have a melting point of at least about 40° C.
The primary alcohol can comprise at least one of fatty alcohols comprising at least one of palmityl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, ceryl alcohol, montanyl alcohol, myricyl alcohol, melissyl alcohol, lacceryl alcohol and geddyl alcohol, and synthetic higher aliphatic alcohols comprising at least one of 1-hexadecanol, 1-octadecanol, 1-eicosanol, 1-docosanol, 1-tetracosanol, 1-hexacosanol, 1-octacosanol, 1-triacontanol, 1-dotriacontanol and 1-tetratriacontanol.
The alcohol alkoxylate component can comprise C
12
to C
18
alcohol alkoxylates, preferably C
12
to C
18
alcohol alkoxylates containing ethylene oxide groups and propylene oxide groups.
The alcohol alkoxylate component can have a cloud point of at least 16° C., with one cloud point range being about 20° C. to 38° C., and another cloud point range being about 22° C. to 25° C.
The alcohol alkoxylate component can have a molecular weight of at least about 630, more preferably about 630 to 3,000, and even more preferably about 1,200 to 3,000.
The emulsifier component can comprise at least one nonionic surfactant, and can additionally comprise at least one anionic surfactant.
At least one branched alcohol can be added. Moreover, at least one of stabilizing and thickening agents can be added.
The primary alcohol component, the alcohol alkoxylate component and the emulsifier component can be added by adding an aqueous defoaming composition to the aqueous system. The aqueous defoaming composition can comprise about 10 to 35 weight percent primary alcohol, about 2 to 12 weight percent alcohol alkoxylate, and about 0.2 to about 5 weight percent of emulsifier component.
The emulsifier component can comprise up to about 1.0 weight percent of at least one anionic surfactant, and from about 0.2 to 5.0 weight percent of at least one nonionic surfactant. The at least one nonionic surfactant can comprise at least one alcohol ethoxylate. Moreover, the emulsifier component can comprise at least one water soluble alcohol ethoxylate and at least one water insoluble alcohol ethoxylate.
The aqueous system can be, for example, a papermaking system.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of provi
Metzmaier Daniel S.
Wegman Hessler & Vanderburg
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