Reducing cloud point

It should be noted that the saturated fractions are a natural portion of the product and that this fallout is a natural characteristic of the product. Some users have requested methyl lardate with lower levels of fallout or no fallout. In an attempt to provide this product, manufacturers have blended certain crystal inhibitors. Up to 15% methyl esters of less saturated vegetable oils have been blended in to reduce cloud point and fallout, but some problems may result as the unsaturated fatty esters perform differently in high heat metalworking processes. However, vegetable oils are typically more expensive than the rendered fats, and the practice of blending in methyl esters of vegetable oils makes the resultant product more expensive. 

The critical point (Ij of the two-phase region encountered at reduced temperatures is called an upper critical solution temperature (UCST), and that of the two-phase region found at elevated temperatures is called, perversely, a lower critical solution temperature (LCST). Figure 2 is drawn assuming that the polymer in solution is monodisperse. However, if the polymer in solution is polydisperse, generally similar, but more vaguely defined, regions of phase separation occur. These are known as "cloud-point" curves. The term "cloud point" results from the visual observation of phase separation - a cloudiness in the mixture. 

Shrinking of the polymer chains as a function of temperature was observed by capillary viscometry. The reduced viscosity, r]Sp/c, of polymer solutions approaches zero when the polymers are in their fully collapsed compact state and flow freely through the capillary. Above the cloud point, rjSp/c increases, which is indicative of aggregate formation. At low temperatures the... 

While such data are not included in this report, our work has also shown that in FCC operations the acidic matrix is able to better crack and isomerize more n-paraffins, thus reducing the n-paraffin content in middle distillate and thereby the characteristic high cloud point associated with it, while also raising octane number by removing or isomerizing n-paraffins in the gasoline fraction. 

It is possible to dilute diesel fuel such as 2-D low sulfur with kerosene, 1 fuel oil, or jet fuel to reduce the fuel cloud point. Also, additives are also marketed which have the ability to inhibit nucleation of wax crystals in some fuels, thereby lowering the cloud point of the fuel. These products are called cloud point improvers. 

The use of kerosene or 1 fuel oil in reducing the cloud point of distillate fuel is common practice. By diluting the fuel with these lighter streams, wax-related problems can be minimized, but not eliminated. As a general rule a reduction in... 

Low-temperature distillate fuel pumpability and viscosity can be reduced below that of an untreated fuel. Below the cloud point, fuel which does not contain a wax crystal modifier is difficult to handle and pump effectively. Wax crystal modifiers help minimize pumpability problems related to yield stress and viscosity. 

Fuels treated with a cloud point improver (CPI) may require additional CPI treatment whenever a wax crystal modifier is used to reduce the pour point of the fuel. Often, the cloud point of a CPI-treated fuel will increase whenever a pour point improver is used. To compensate for this phenomenon, additional CPI must be added to recover the lost performance. 

Lowering the cloud point and pour point values of a distillate fuel can be accomplished by blending the fuel with a low-wax-content distillate stream such as a kerosene or jet fuel. Also, additives are frequently used in conjunction with kerosene blending or as a substitute for kerosene blending to reduce the pour point of diesel fuel. Additives are not as frequently used to reduce the cloud point of diesel fuel. 

H. Noureddini, in System and process for producing biodiesel fuel with reduced viscosity and a cloud point below thirty-two (32) degrees fahrenheit , US, 2001. 

Because the sarcosinates have the ability to raise the cloud point of nonionic surfactants, this feature can be used to advantage in the formulation of dishwasher rinse aids. At the cloud point and up to 15C above it, foam generation is reduced and detergency is enhanced. By adjusting the cloud point of the formula to the use temperature, one can take full advantage of this performance feature. 

Addition of a wax modifier to crude disrupts the normal crystallisation mechanism of wax, thereby reducing wax deposition. Since the chemical reacts during the onset of crystallisation by co-crystallisation, it is only effective when introduced at temperatures above the cloud point. 

Petro BAF, in combination with sodium lauryl sulfate, reduces the low temperature cloud point, giving excellent freeze/thaw properties. The Petro BAF combination dries less tacky than sodium lauryl sulfate alone. 

Studies on non-ionic surfactants as effective drag-reducing additives have been submitted by Zakin (1972). He studied various effects on three non-ionic surfactants formed from straight-chain alcohols and ethyleneoxide. These surfactants have an upper and a lower temperature limit for solubility in water and prove effective drag reducers near their upper critical solubility temperature or clouding point. The clouding point is the point at which a solution of a non-ionic agent in water becomes turbid as the temperature is raised. 

Figure 31. Cloud point of ethoxylates at reduced concentrations...

Applications. Sarcosinates show low irritation potential and are good foamers. Due to these properties they find applications in personal care products where synergistic effects with other surfactants may also be exploited. In combination with other anionics, sarcosinates will often detoxify the formulation and give improved foaming and skin feel. Sarcosinates are also used for their hydrotropic properties - the addition of sarcosinate to other anionics often gives a reduced Kraft point or a raised cloud point if combined with non-ionic surfactants. Lauroyl sarcosinate is used to formulate SLS-free toothpastes which are claimed to have improved taste profile. 

The opposite behavior as sketched before was detected for solutions of PS in DOP [112], Again, the critical temperature (an UCST at Tc = 12 °C in the quiescent state) turned out to be a function of the shear rate to which the solution is subjected. But, in contrast to solutions of PS and PB in DOP, here enhancements of the UCST as large as 28 °C were recorded at a shear rate of 220 s-1. Similar results have been found for PS solutions in di(2-ethyl hexyl)phthalate or in a mixture of cis- and frans-decalin [113], The solutions demixed in a converging flow from a reservoir into a capillary tube. It has been observed that an increase in the deformation rate raised the UCST or reduced the region of miscibility. In both of these studies an increase of the cloud point temperature of the polymer solutions was used as an indication of phase separation. 

Noureddini, H. 2000. Process for Producing Biodiesel Fuel with Reduced Viscosity and a Cloud Point Below 32 °F. United States Patent 6015440 (Jan. 18). 

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