Cloud point improver

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. 

Pour Point Improvers—Wax Crystal Modifiers (WCM)—Cloud Point Improvers... 

Certain cloud point improvers function by effectively inhibiting the nucleation of wax crystals. This can be accomplished by dispersion of the wax, thus interfering with nucleation. By functioning as an effective dispersant, certain cloud point improvers can help to solubilize water into fuel to give the fuel a cloudy, hazy appearance. As little as 200 ppm of a cloud point improver can create an opaque, relatively stable haze in treated distillate fuel. 

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. 

A secondary problem may occur whenever CPI treated fuels are blended with other fuels in a fungible system. The effect of the cloud point improver may be lost due to dilution or limited performance in other fuels. 

Certain cloud point improvers will disperse water into fuel and create an emulsion or haze. This phenomenon can occur at cloud point improver treat rates as low as 200 ppm. 

Determine whether a cloud point improver was utilized in the fuel by checking blending records. 

One remaining possibility that is less costly from an energy point of view but needs to be carefully controlled is to incorporate additives called flow improvers. These materials favor the dispersion of the paraffin crystals and in doing so prevent them from forming the large networks which cause the filter plugging. The conventional flow improvers essentially change the CFPP and pour point, but not the cloud point. They are usually copolymers, produced, for example, from ethylene and vinyl acetate monomers ... 

Figure 5.9 shows an example of the efficiency of these products. The reductions of CFPP and pour point can easily attain 6 to 12°C for concentrations between 200 and 600 ppm by weight. The treatment cost is relatively low, on the order of a few hundredths of a Franc per liter of diesel fuel. In practice, a diesel fuel containing a flow improver is recognized by the large difference (more than 10°C) between the cloud point and the CFPP. 

The nature of these paraffins and their concentration in diesel fuel affect the three temperatures that characterize the cold behavior. The cloud point is the temperature at which crystals of paraffins appear when the temperature is lowered. The cold filter pluming point is defined as the temperature under which a suspension no ionger flows through a standard filter. Finally, the pour point is the temperature below which the diesel fuel no longer flows by simple gravity in a standard tube. These three temperatures are defined by regulations and the refiner has three types of additives to improve the quality of the diesel fuel of winter. 

Lower cloud point in the diesel fuel. Isoparaffins in the light cycle oil boiling range improve the cloud point. 

As the temperature of dilute aqueous solutions containing ethoxylated nonionic surfactants is increased, the solutions may turn cloudy at a certain temperature, called the cloud point. At or above the cloud point, the cloudy solution may separate into two isotropic phases, one concentrated in surfactant (coacervate phase) and the other containing a low concentration of surfactant (dilute phase). As an example of the importance of this phenomena, detergency is sometimes optimum just below the cloud point, but a reduction in the washing effect can occur above the cloud point (95). However, the phase separation can improve acidizing operations in oil reservoirs (96) For surfactant mixtures, of particular interest is the effect of mixture composition on the cloud point and the distribution of components between the two phases above the cloud point. 

Suzuki et al. reported cloud-point temperatures as a function of pressure and composition in mixtures of poly(ethyl acrylate) and poly(vinylidene fluoride) [9], Their data in terms of p(T) curves at constant composition show that miscibility in the same system may either improve or decline with rising pressure, depending on the blend s composition. Important consequences for blend-processing ensue. A planned two-phase extrusion may easily be jeopardized by the pressure building up in the extruder. Conversely, a homogeneous melt may be turned into a two-phase system when the pressure on the blend increases. 

To improve the cold properties of biodiesel, the use of alcohol with longer alkyl chain has been studied in the alkaline-catalyzed method. The cloud point for ethyl esters is approx 2°C lower than that of the corresponding methyl esters, while butyl esters are 10°C lower than methyl esters (6). Furthermore, cetane number is appropriate for alkyl esters from the alcohol with the longer alkyl chain (7). 

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. 

Lrizzarin, R.M., Rocha, F.R.P. An improved approach for flow-hased cloud point extraction. Anal. Chim. Acta 820, 69-75 (2014)... 

Sometimes additives are used to improve the low-temperature fluidity of diesel fuels. Such additives usually work by modifying the wax crystals so that they are less likely to form a rigid structure. Thus, although there is no alteration of the cloud point, the pour point may be lowered dramatically. Unfortunately, the improvement in engine performance as a rule is less than the improvement in pour point. Consequently, the cloud and pour point temperatures cannot be used to indicate engine performance with any accuracy. 

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