Plugging filter

The characteristics of diesel fuel taken into account in this area are the cloud point, the pour point, and the cold filter plugging point (CFPP). 

The cold filter plugging point (CFPP) is the minimum temperature at which a given volume of diesel fuel passes through a well defined filter in a limited time interval (NF M 07-042 and EN 116 standards). For conventional diesel fuels in winter, the CFPP is usually between —15 and —25°C. 

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 ... 

Additives acting on the pour point also modify the crystal size and, in addition, decrease the cohesive forces between crystals, allowing flow at lower temperatures. These additives are also copolymers containing vinyl esters, alkyl acrylates, or alkyl fumarates. In addition, formulations containing surfactants, such as the amides or fatty acid salts and long-chain dialkyl-amines, have an effect both on the cold filter plugging point and the pour point. 

Cold filter plugging point EN 116 (NF M 07-042) Vacuum filtration through a calibrated filter... 

Some additives have the ability to lower the pour point without lowering the cloud point. A number of laboratory scale flow tests have been developed to provide a better prediction of cold temperature operability. They include the cold filter plugging point (CFPP), used primarily in Europe, and the low temperature flow test (LTFT), used primarily in the United States. Both tests measure flow through filter materials under controlled conditions of temperature, pressure, etc, and are better predictors of cold temperature performance than either cloud or pour point for addithed fuels. 

Filter plugged index to monitor the condition of each stages of filters... 

Triacetin resistance is especially critical when filter tips are made in one location, stored, and then shipped to another location. For these operations, polyethylene-based adhesives are used because of their low polarity and therefore excellent resistance to triacetin. Where filter plugs are attached at the same location shortly after production, EVA-based adhesives are suitable and preferred. Both types of adhesives use low odor, clean tackifiers such as hydrogenated hydrocarbons or pure monomer resins (typically a-methylstyrene based). Rosin, rosin esters, and phenol-containing tackifiers are not acceptable. EVA-based adhesives use a higher level of wax (about 1 /3 of the formula) than polyethylene-based adhesives (5-20% wax) due to the lower crystallinity and slower set of EVA vs. PE. Application viscosities are 2000-5000 cP. 

The Pd-C catalyst was then removed by filtration through Celite in a sintered glass funnel with the aid of a water aspirator. The filtration was completed by rinsing the packing with 95% ethanol (75 mL). Attention due to the pyrophoric properties of hydrogen-saturated palladium, it is important to keep the filter plug under a layer of ethanol. 

Water and particulates are the source of fuel quality problems such as filter plugging, corrosion, and system component fouling. Water can be removed through salt drying, coalescence, filtration, and good housekeeping. 

The cloud point measurement is used to predict the temperature at which wax in fuel may begin causing operating problems such as filter plugging and blockage of lines in fuel systems. 

Fuel stability is an indication of the sediment- and gum-forming tendency of fuel. Gums and sediment can cause filter plugging and combustion chamber deposits and result in sticking of pumping and injection system components. 

Filter plugging and burner problems can be caused by the presence of water-insoluble sediment and waterborne solids in residual fuel. Specifications on water and sediment typically range from 1 to 2 vol%. 

As salts, these inhibitors can readily interact with water to form emulsions. The ability of the inhibitor to effectively prevent fuel system corrosion is lost. Once emulsified, corrosion inhibitors can initiate other problems such as filter plugging and sticking of moving parts. 

Also, the gel-like emulsion formed can be pumped with the fuel volume and accumulate on fuel filters. The result of this accumulation is usually filter plugging, pump sticking, and possible engine shutdown. 

Fuels such as diesel fuel and heating oil are sometimes stored in large tanks for extended periods of time. At temperatures below the cloud point of the fuel, wax can form and fall from solution. Accumulated wax within fuel systems can deposit onto component parts and settle into areas of low turbulence. Problems such as filter plugging and flow limitations can be due to accumulated wax. 

Wax-related problems are common throughout the petroleum product industry. Fuels and lubricants contain wax at varying concentrations. Filter plugging, line blockage, viscosity increase, and product haziness are all symptoms of wax formation within a fuel or oil. 

This wax can accumulate on fuel filter media and can lead to plugging of small orifices and lines. This plugging temperature can be measured and is commonly referred to as the filter plugging temperature. Testing methods utilized to predict the filter plugging temperature and the low-temperature flow properties of distillate fuel are listed in TABLE 4-5. 

Simulated filter plugging point (SFPP) Proposed European standard... 

COLD FiLTER PLUGGING POINT (CFPP) REDUCTION... 

The cloud point and the cold filter plugging point temperatures for fuel which does not contain a wax crystal modifier can often be the same. Typically, untreated cloud point and CFPP values will be within 2°F to 4°F (about 1°C to 2°C) of each other. If the temperature difference between an untreated fuel s cloud point and CFPP differ by 10°F (5.6°C) or more, the fuel probably contains a wax crystal modifier. 

Wax dropout or settling from fuel during long-term storage. The result is accumulation of a wax layer at the bottom of a storage tank. This accumulated wax can cause line and filter plugging when pumped from the tank bottom and into vehicles. 

As the fuel passes through various tank and line filters, rouge can be trapped by the filter media. Filter plugging and halting of fuel flow through the filter can result. 

For this reason, it is recommended that addition of corrosion inhibitor to previously uninhibited systems be closely monitored. Initial low level addition followed by a gradual increase in the corrosion inhibitor treat rate will help to minimize the removal of pipeline rouge and filter plugging problems. 

Diesel fuel and kerosene alone are not effective solvents for use in solubilizing most WCMs for low-temperature application. The low KB value of diesel fuel and kerosene makes these fuels ineffective at holding the WCM in solution for extended periods of time at low temperatures. Stratification and separation of the WCM from solution can lead to application problems such as filter plugging and inaccurate WCM treatment. 

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