Deodorization systems

Experience has shown that edible fats and oils flavor and odor removal correlates well with the reduction of FFA. The odor and flavor of an oil with a 0.1 % FFA will be eliminated when the FFA is reduced to 0.01% to 0.03%, assuming a zero peroxide value. Therefore, all commercial deodorization consists of steam stripping the oil for FFA removal. Typical conditions practiced in the United States for the three deodorizer system types are shown in Table 23. The four interrelated operating variables that influence deodorizer design are vacuum, temperature, stripping rate, and retention time at deodorization temperatures. 

The net heating energy required for a deodorization system can be calculated as ... 

In addition to equipment suppliers already mentioned in this chapter (Alfa-Laval, De Smet, Tirtiaux), there are a number of other suppliers of commercial-deodorizer systems for oils and fats (e.g., Andreotti, CMB, Crown, Kirchfeld, Krupp, Lipico, Oiltek, etc.). 

EPA,( May 1998) Chemical Emergency Preparedness and Prevention Office. Fire hazard from carbon adsorption deodorizing systems. EPA 550-F-97-002-e. 

Chemical Safety Alert Fire Hazard From Carbon Adsorption Deodorizing Systems (PDF) (3 pp, 186K) Issued May 1997... 

Steam stripping system is more complex and can be cost prohibitive. Figure 11.2 shows a schematic diagram for a steam deodorization system. In order to get the full benefit of this type of treatment, one must have a system where the adsorbent treatment precedes the steam deodorization step. 

Sprays. Aerosol spray emulsions are of the water-in-oil type. The preferred propellant is a hydrocarbon or mixed hydrocarbon—hydrofluorocarbon. About 25 to 30% propellent, miscible with the oil, remains in the external phase of the emulsion. When this system is dispensed, the propellant vaporizes, leaving behind droplets of the w/o emulsion (Fig. 2b). A vapor tap valve, which tends to produce finely dispersed particles, is employed. Because the propellant and the product concentrate tend to separate on standing, products formulated using this system, such as pesticides and room deodorants, must be shaken before use. 

Deodorization can be carried out ki batch, continuous, or semicontkiuous systems. Figure 4 shows a typical design for a semicontkiuous deodorizer. The heated ok is passed through a series of trays under vacuum. Steam is passed through the ok through a steam sparge ki the bottom of the tray. Volatiles are carried through the headspace and condensed. In addition to fatty acids and compounds responsible for odor, some tocopherols and sterols are also distilled kito the condensate. The amount of tocopherols distilled depends on deodorization temperature and vacuum. 

Many gas streams can be deodorized by using solid adsorption systems to remove the odor before the stream is released to the atmosphere. Such procedures are often both effective and economical. 

The oxidative degradation of organic pollutants in water and air streams is considered as one of the so-called advanced oxidation processes. Photocatalytic decomposition of organics found widespread industrial interest for air purification (e.g., decomposition of aldehydes, removal of NO , ), deodorization, sterilization, and disinfection. Domestic applications based on Ti02 photocatalysts such as window self-cleaning, bathroom paints that work under illumination with room light, or filters for air conditioners operating under UV lamp illumination have already been commercialized. Literature-based information on the multidisciplinary field of photocatalytic anti-pollutant systems can be found in a number of publications, such as Bahnemann s [237, 238] (and references therein). 

Even if few systems are proposed for inorganic compounds (with regard to the number of potential pollutants), instruments or sensors for parameters used for treatment process control are available UV systems for residual chlorine in deodorization, electrochemical sensors for dissolved oxygen (with nowadays a luminescent dissolved-oxygen probe utilizing a sensor coated with a luminescent material) and a colorimetric technique for residual ozone. 

Semiconductor surfaces, 9 730-731 Semiconductor technology, 19 127 Semiconductor transport, 22 237-239 Semiconductor-vacuum interface, 22 241 Semicontinuous deodorizer, 10 815 Semicontinuous dyeing, 9 211-213 Semicontinuous ion-exchange systems, 14 403... 

No histopathological changes were noted in the gastrointestinal system of rats or dogs exposed to up to 100 mg/m deodorized kerosene vapor for 13 weeks (Carpenter et al. 1976). Inhalation of diesel fuel aerosol 4 hours/day, 2 days/week, for 13 weeks at concentrations up to 1,500 mg/m did not induce histopathological changes in the gastrointestinal system of rats (Lock et al. 1984). 

Gawororski et al. 1984). Finally, no systemic or neurological effects were observed in rats or dogs exposed to a deodorized kerosene concentration of 100 mg/m (Carpenter et al. 1976). 

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