Flow improving additives

Effect of Flow Improver Additives on Paraffin Deposition... 

Table 2. Flow improving additives used to date...

Alternatively, low-temperature flow test (ASTM D-4539) results are indicative of the low-temperature flow performance of fuel in some diesel vehicles. This test method is especially useful for the evaluation of fuels containing flow improver additives. In this test method, the temperature of a series of test specimens of fuel is lowered at a prescribed cooling rate. At the commencing temperature and at each 1°C interval thereafter, a separate specimen from the series is Altered through a 17-mm screen until a minimum low-temperature flow test pass temperature is obtained. The minimum low-temperature flow test pass temperature is the lowest temperature, expressed as a multiple of 1°C, at which a test specimen can be Altered in 60 s or less. 

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. 

Fuel oil flow-improving additives Netherlands 10,661 PLASTICS 1979 Exxon Research... 

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)...

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 ... 

Retrofitting features of the more efficient reactor types have been the principal thmst of older methanol plant modernization (17). Conversion of quench converters to radial flow improves mixing and distribution, while reducing pressure drop. Installing an additional converter on the synthesis loop purge or before the final stage of the synthesis gas compressor has been proposed as a debotdenecking measure. 

Amiodarone relaxes vascular smooth muscle one of its most prominent effects is on the coronary circulation, reducing coronary vascular resistance and improving regional myocardial blood flow. In addition, its effects on the peripheral vascular bed lead to a decrease in left ventricular stroke work and myocardial oxygen consumption. Therefore, amiodarone improves the relationship between myocardial oxygen demand and oxygen supply. IV administration may be associated with profound hypotension requiring volume expansion therapy. 

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). 

Large-scale applications are limited because of the sensitivity of polymers to chemical, thermal, and/or mechanical degradation (Martischius). Thus, the use of polymers should either be limited to open-ended systems with short distances to be covered (such as in the use of water hoses in fire fighting) or an additional injection device must be used in pipeline transportations, to automatically adjust the content of (fresh) flow improvers in case of decreased effectiveness. 

Within this group, the linear polymers have been most intensively studied and researched. The main area of interest lies in water-soluble polymers. However, there have also been many studies into organic solutions, although there exist problems with odor and toxicity in the case of analytical studies. Among the water-soluble additives, tests were made especially on polyethyleneoxide (PEO), polyacrylamide and the coacrylates (PAAm, PAAm/AAcNa), polyacrylic add (PAA), guar gum (GG), carboxymethylcellulose (CMC) and sodium salts, as well as hydroxyethylcellulose (HEC). From these tests, PEO proved to be the most effective flow improver, followed closely by PAAm, which is somewhat more stable than PEO in turbulent flow. 

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. 

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-... 

If a powder flows poorly, the vibrator can be used, but it also causes powder segregation and stratification. The addition of glidant (occasionally lubricant) in the powder mixtures can readily increase flowability at the low concerntration. Talc or fumed silicon dioxide is an example of a glidant. If this is not sufficient to improve the flow, other means of flow improvement are necessary. There are two main factors that affect powder flow particle size and particle shape. The more spherical a particle is, the better it flows. Small particles are very cohesive and hence do not flow well, but increasing the particle size will improve flow. With the aid of spray drying or spheronizers, particles become spherical. 

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. 

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