Foam control additives

Diesel fuel usually has some moisture in it that affects the function of foam control additives - which must be chosen such that they are able to function in the expected range of moisture contents. The origin of the foaminess is poorly understood but silicone polyalkyleneoxide copolymers are effective defoamers as long as they are neither completely soluble in the fuel, nor absorbed and deactivated by the water. Polyoxypropylene containing copolymers appear to be the most effective. 

The personal care industry remains traditionally the largest consumer of soaps depending on the region, from 50 to 75 % of the total surfactant consumption accounts for soaps [81], The increase in body shampoo consumption last decades is assumed to alter the soap market slightly. The consumption rate of soap in household and laundry aids is quite modest now and limited essentially by the "old times" detergents, foam-control additives, chlorine-containing alkali cleaners, and metal cutting oils. The sodium salts of rosin acids and wool wax acids are of some importance for technical needs and bar soaps. 

An essential piece of equipment in recyclable systems is a well-designed mud-gas separator. The function of the separator is to disengage the gas and liquid phases. When the foam control additive is introduced... 

Uses Cleaning/foam controlling additive for acidic or alkaline detergents, pressure spray washing... 

Other. Because a foam consists of many small, trapped gas bubbles, it can be very effective as a thermal insulator. Usually soHd foams are used for insulation purposes, but there are some instances where Hquid foams also find uses for insulation (see Eoamed plastics Insulation, thermal). Eor example, it is possible to apply and remove the insulation simply by forming or coUapsing the foam, providing additional control of the insulation process. Another novel use that is being explored is the potential of absorbing much of the pressure produced by an explosion. The energy in the shock wave is first partially absorbed by breaking the bubbles into very small droplets, and then further absorbed as the droplets are evaporated (53). 

Special additives are often included in a carrier formulation to provide specific properties such as foam control, stabiUty, and fiber lubrication during dyeing. Most important are the solvents used to solubilize the soHd carrier-active chemicals. These often contribute to the general carrier activity of the finished product. For example, chlorinated benzenes and aromatic esters are good solvents for biphenyls and phenylphenols. Flammable compounds (flash point below 60°C) should be avoided. 

The use of a chemical agent as an anti-foam is affected by an on-off algorithm with variable dosing time and time delay. If the presence of foam is detected, then the controller first activates a delay timer. This type of foam controller works with some delay and variable dosing time. If at the end of the delay period the foam is still present, then the dosing pump is activated and chemical agent is added to the bioreactor. If the foam is still detected at the end of this period, the combined system of delay and dosing is reactivated. With this method of controller, addition of any unnecessary anti-foam is prevented. 

Fourteen formulations of chemical alternatives were submitted to EPA under confidentiality and they were assessed based on numerous human health and ecotoxicity endpoints in addition to bioaccumulation potential and environmental persistence. They were also screened for potential exposure to workers, users and the aquatic environment. Where data gaps existed, EPA experts used models and chemical analogs to estimate the hazard for a particular endpoint. The literature and test data reviews were published in the final report, Environmentally Preferable Options for Furniture Fire Safety Low Density Furniture Foam . In addition, each hazard endpoint was ranked with a concern level (High, Moderate or Low) based on the criteria used by the EPA s New Chemicals Program to rate the concern level of new chemicals submitted under the Toxic Substance Control Act (TSCA). As seen in Figure 8.2, where the hazard endpoint rankings are bold, the value is based on experimental data. Where the hazard endpoints are presented in italic font, the value is estimated based on models or chemical analogs. In this way, detailed hazard information was summarized and presented in a clear and concise format. 

Some chemical additives such as corrosion inhibitors, wax crystal modifiers, detergents, and demulsifiers provide performance which is difficult to duplicate through refining without adversely affecting some other fuel property. Other additives such as metal chelators, fuel sweeteners, biocides, lubricity improvers, foam control agents and combustion enhancers can also be used to solve fuel performance problems. 

While we are dealing mostly with open-cell foams, control of the degree of openness also has an effect on tensile properties. Saunders reported on the control of open-cell structures by the addition of a stannous catalyst. They showed maxima... 

Foam Control. Fermentations tend to froth because metabolites have surfactant properties. Prevention commonly is by addition of antifoam agents such as oils, heavy alcohols, fatty acids, or silicones. High-speed rotating impellers destroy bubbles by direct impact and by throwing them against the wall of the vessel. 

HERCULES 831 defoamer is a quick-dispersing, hydrocarbon oil-based antifoaming agent designed for use where immediate foam-control action is wanted. It is particularly suitable where addition adjacent to the foam-control point is required. Its efficiency is not adversely affected by temperature or pH, and it is effective in the presence of many surfactants. 

HERCULES 831 defoamer readily disperses in aqueous systems and develops its foam-control action rapidly. Thus, it can be used where little agitation is available to disperse the foam killer, or where it must be added adjacent to the point of foam control. Preferably, 831 defoamer should be added as received to the foaming system. However, for ease of metering, it can be dispersed with continuous agitation in aqueous systems prior to addition. 

Use Flame-retardant plasticizers for vinyls, dust filter medium, gas additives, wood-treating chemical, foam control. 

Figures 40 and 41 demonstrate a different foam behavior, for the Chaser SD1020 foam-flooding additive at 90, 120, and 175 °C, at high-(200 psi) and at low- (slightly above the vapor pressures at the given temperatures) pressures. The increase in temperature strongly decreases the stability, similar to the previous system. With increasing oil content, the stability goes through a minimum at 90 and 120 °C and slightly increases at 175 °C. The minimum curves indicate that the stability is controlled by at least two processes.

Paperboard This mill produces board for tubes, eores, furniture backing and roll covering on a 160 t/day 7-vat cyUnder-board machine. The system pH is neutral, and the temperature is 60°C. Water systans in this mill are nearly 100% closed. Additives used in the wet-end include alum, rosin size, cationic retention aid and various dyes. Poor foam control results in high entrained air measuronents in the vats (>6%) and... 

Uses Synthetic fibers evaporation retardant on water surfaces surfactant for polymerization emollient in cosmetics foam control agent cosolvent plasticizer mfg. of household/industrial cleaners, personal care prods., textile auxs.. plasticizers, ore flotation, oil well drilling, metal lubricants, agric. additives raw material, consistency agent, emollient for pharmaceuticals as antihistamine in surf, lubricants for mfg. of food-contact metallic articles Regulatory EDA 21CER 178.3910... 

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