Cold flow improver

In view of decreasing world crude oil reserves and the discussion about the environmentally damaging consequences of the use of fossil and mineral fuels, there is an increasing interest in alternative energy sources based on renewable raw materials. These include in particular natural oils and fats of vegetable or animal origin (26). 

These oils are in general triglycerides of fatty acids with 10-24 carbon atoms. The carbon atoms and may be saturated or unsaturated. In addition, they may contain phosphoglycerides. Their calorific value is comparable to conventional fuels. However, they are considered to be less harmful to the environment. 

Biofuels are obtained from renewable sources and, when they are combusted, generate only as much CO2 as withdrawn form atmosphere by photosynthesis. Less carbon dioxide is formed in the course of combustion than by the equivalent amount of crude oil distillate fuel, for example diesel fuel. In addition, very little sulfur dioxide is formed. Of course, biofuels are biodegradable. 

Owing to the unsatisfactory physical properties of the triglycerides, the oils are converted into fatty acid esters of low alcohols such as methanol or ethanol. 

A drawback for the use of triglycerides and also of fatty acid esters of lower monohydric alcohols as a replacement for diesel fuel alone or in a mixture with diesel fuel has proven to be the flow 

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Cold flow improvers (pour point depressants) These viscosity improvers are often specified in cold climates for unheated gas oil or where existing residual oil heaters are inadequate. The use of these paraffin crystal modifiers permits fuel to continue to flow at temperatures of 30 to 40 °F lower than the point at which wax crystallization would normally occur. 

MAK fining A petroleum refining process which combines MAK hydrocracking with a cold-flow improvement process. Developed by Nippon Ketjen and first licensed in 1998. 

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... 

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. 

Test method IP 309 is used to determine the low-temperature filterability of distillate fuels including those treated with a cold flow improver. The cold filter plugging point (CFPP) is defined as the highest temperature at which the fuel, when cooled under the prescribed conditions, will not flow through the filter or requires more than 60 seconds for 20 mL to pass through or fails to return completely to the test jar. This method is part of a series of standardized tests developed by the Institute of Petroleum. Test method IP 309 is summarized as follows ... 

Pour point reversion can occur in oils treated with a pour point improver. Often, pour point reversion can be overcome by increasing the cold flow improver treat rate by about 25% to 50%. 

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). 

M. Krull, B. Siggelkow, and M. Hess, Cold flow improvers for fuel oils of vegetable or animal origin, US Patent 7500 996, assigned to Clariant International Ltd. (Muttenz, CH), March 10,2009. 

M.G. Botros, Ethylene vinyl acetate and isobutylene terpolymer as a cold flow improver for distillate fuel compositions, US Patent 5 681359, assigned to Quantum Chemical Corporation (Cincinnati, OH), October 28,1997. 

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. 

Ratio = blend ratios in petrodiesel as defined in Table 1.4 Grade = see Table 1.4 CFI = cold flow improver. See Tables 1.2 and 1.3 for other abbreviations. 

Chiu, C. W., Schumacher, L. G., and Suppes, G. J. 2004. Impact of Cold Flow Improvers on Soybean Biodiesel Blend. Biomass and Bioenergy, 27,485 491. 

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. 

H.W. Homan Free, T. Schockaert and J.M.W. Sonnemans, The Akzo-Fina cold flow improvement process. Fuel Processing Techn., 35, 1993, page 111. 

CarryoL [Sanyo Chent Industries] Fatty acid derivs. cold flow improver and dispersant for fuel oils. 

HartasisL [Hart Chem. Ltd.] Defoamer fOTcementing, drOlmg muds dedusting agent for coal paraffin dispmants for oilfield s cs. cold flow improver for oil deposits heavy-duty cleaner. 

Keroflux . [BASF AG] Lowm.w.wax cold flow improvers and filtration aids for middle distillates in the mineral oil industry. 

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... 

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. 

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. 

DF and Biodiesel Blends Impact of Cold Flow Improver... 

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)...

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. 

Uses Cold flow improver for oil deposit heavy-duty cleaner... 

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