Diesel cold flow improvers

Cold composite curve, 23 191 Cold-ethanol precipitation, 22 135-136 Cold exhaust dyeing, 9 176-177 Cold flow improvers, for diesel fuel, 22 427-428... 

The addition of small amounts of cold flow improvers (also known as pour point depressants) brings the pour point of the diesel into the normal range. This can be achieved for example by addition of 1000 ppm of Callington Haven Roxdiesel Pour Point Depressant. 

An additive to improve flow of diesel fuel in cold weather. In some instances, a cold-flow improver may improve operability by modifying the size and structure of the wax crystals that precipitate out of the fuel at low temperatures, permitting their passage through the fuel filter. 

Anti-oxidation Cetane improvement Dispersion Anti-icing Detergent Metal passivation Corrosion inhibition Cold-flow improvement Minimize oxidation and gum formation during storage Increase cetane number Improve behavior in fuel injectors Minimize ice formation during cold weather Control deposition of carbon in the engine Deactivate trace metals that can accelerate oxidation Minimize rust throughout the diesel fuel supply chain Improve flow characteristics in cold weather... 

This section shows how DSC and thermomicroscopy can be used to study the cold flow behavior of two biodiesels (palm oil methyl ester (MEl) and rapeseed oil methyl ester (ME2)) and their blends with a conventional diesel fuel (DF). The impact of a cold flow improver on the quantity and size of crystals is also presented. 

Low temperature operability additives lower a diesel fuel s pour point and improve its cold flow properties. Most of these additives are polymers that interact with the wax crystals that form in diesel fuel when it is cooled below the pour point. The added polymers mitigate the adverse effect of wax crystal formation on fuel flow by modifying their size, shape, and degree of agglomeration. The polymer-wax interactions are fairly specific. As such, a particular additive generally will not perform equally well in all fuels. Unfortunately, the best additive for a particular fuel cannot be predicted it must be determined experimentally. 

Petroleum-based diesel fuel is commonly treated with a large number of additives to enhance cetane number, improve cold flow and oxidative stability, lessen corrosive-... 

Moreover, specific additives, such as demulsifiers and flow improvers, can improve some specific properties of diesel fuels, especially in cold weather conditions. 

In most cases, the additive depresses the pour point, which delays agglomeration of the wax crystals, but usually has no significant effect on diesel engine performance. A preferred means of improving cold flow is to blend kerosene with the diesel fuel, which lowers the wax appearance point by about 10° C for each 10% increment of kerosene added. 

The chemical composition of a fuel is very complex and generally a lot of additives are added in order to improve some properties such as viscosity, oxidative stability, cold flow behavior, cetane number, color or smell etc. The impact on fuel properties of a complex mixture of miscellaneous additives is not always very well known. It has been already shown that it can bring a positive or negative synergy. Therefore, DSC and P-DSC can be very useful in evaluating with high accuracy and in a reasonable time the impact of a package of additives on the oxidative stability or the cold flow behavior of an alternative or conventional diesel fuel. 

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. 

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