Cold flow improver additive

Palm and rapeseed biodiesels were mixed with cold flow improvers (additives) after adding them to DF. The additives were mixtures of ethylene vinyl acetate (EVA) copolymers and naphthenic distillates. 

The same analytical techniques as those presented before are used to study the impact of 200 ppm of a cold flow improver (additive A ) on the morphology of... 

Fig. 13.7 Comparison of crysttd morphology at —15 °C between biodiesel blends (DF/ME2) with and without cold flow improver (additive A)...

In addition to refining techniques, compounds identified as wax crystal modifiers are available for use in contending with the effects of wax in fuels. Wax crystal modifiers, also called pour point depressants or cold flow improvers, are typically polymeric compounds which have the ability to crystallize with fuel wax as it forms. By co-crystallizing with wax, the modifiers typically effect a change in the size, shape, and conformation of wax crystals. Other wax crystal modifiers function by dispersing or inhibiting the nucleation or growth of wax crystals within a fuel or oil. 

However, a method to improve the flow properties of such fuel oils of animal or vegetable origin, has been developed (26). This consists in adding a EVA copolymer or a comb polymer based on methyl acrylate and a-olefins. In addition, terpolymers of ethylene, vinyl acetate and isobutylene have been found to be useful as cold flow improvers (29). 

Many approaches for improving the cold flow properties of biodiesel have been explored. These include blending with petrodiesel, transesterification with medium or branched-chain alcohols instead of methanol or ethanol, crystallization fractionation, and treatment with cold flow improver (CFI) additives. 

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. 

Many applications of dispersions require a number of properties in the end use which can be achieved by the addition of fillers, pigments, leveling enhancement additives, flow improvement additives, and other additives. For example, cold flow (creep) properties of the coating can be reduced by the addition of fillers such as fiberglass. Additives should be mixed only by mild stirring to avoid coagulation of PTFE. 

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. 

By adding 200 ppm of a cold flow improver, the size of crystals was greatly reduced for all the biodiesels and biodiesel blends studied. Therefore, the cold flow behavior was improved, but no impact on the quantity of crystals was obtained. This means that the additive used only had an impact on the nucleation and growth of particles. 

M. Feustel, M. Krull, and H. J. Oschmann. Additives for improving the cold flow properties and the storage stability of crude oil (Additive zur Verbesserung von KaltflieBeigenschaften und Lagerstabilitat von Roholen). Patent WO 0196503, 2001. 

The most remarkable difference between PTFE and PFA is the considerably lower resistance to deformation under load (cold flow) of the latter. In fact, addition of even minute amounts of PFA to PTFE improves its resistance to cold flow52 (see also Section 8.7). 

Two reports in the patent literature claim the invention of CFI additives specifically designed to improve the cold weather performance of biodiesel (Scherer and Souchik, 2001 Scherer et al, 2001). Block copolymers of long-chain alkyl methacrylates and acrylates were effective as PPD and flow improv-... 

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. 

Poly(isobutylene) only crystallizes under stress. Because of the low glass transition temperature (-70 C), its lack of crystallinity, and the somewhat weak intermolecular forces, poly (isobutylene) is an elastomer. The low-molar-mass material is used as an adhesive or viscosity improver. The higher-molar-mass products are employed as rubber additives or for very airtight tubes. The cold flow (creep) can be diminished or eliminated by the addition of polyethylene. Poly(isobutylenes) modified by copolymerization are used as protective sheeting for building sites and as anticorrosive coverings (e.g., a copolymer of 90% isobutylene and 10% styrene). 

Another classification system is based on the mode of action of the additive. A plasticizing additive produces plasticized polymers irrespective of whether the additive is of low or high molar mass. Some additives work in a reinforcing manner, although the reinforced property should always be stated. For example, the tensile strength, the impact strength, or the resistance to cold flow may be improved. Since such a classification is based on the mode of action and not on the structure, block and graft polymers are sometimes classified as blends and composites. Such polymers can exist in several phases, but they are not physical mixtures. 

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. 

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