Mais conteúdo relacionado



Fuel Additives, Lecture 02, Fuel Tech-ll.pdf

  1. Fuel-additives are a class of performance modifiers that are added to gasoline/fuels to enhance certain properties and/or to provide additional properties not present in the gasoline. Fuel additives are used as combustion modifiers, antioxidants, corrosion inhibitors and deposit control detergents.
  2. Types of additives  Acetone.  Ether.  Nitrous Oxide (Nitrous)  Nitromethane (Nitro)  Butyl Rubber.  Ferox.  Oxyhydrogen.  Ferrous Picrate
  3. Importance of Fuel Additives  Gasoline Stabilizers Loss of a gasoline’s volatility become a problem for normal driving, and also a major problem when starting seasonal-use vehicles like boats, motor homes, lawn care equipment and electric generators. Using a gasoline stabilizer basically reduces hard-starting caused by the tendency of the more gaseous components of gasoline to evaporate into the atmosphere.  Fuel-Line Antifreeze water condensation normally found in gasoline storage tanks and in automobile fuel tanks often caused the fuel line to freeze during cold weather. The historic remedy is to add various alcohol-based fuel line antifreezes that will mix with the water to prevent fuel line freeze-up.
  4.  Octane Boosters Ethyl lead was used in gasoline/fuel for many years to increase the gasoline’s octane rating and lubricate engine valve seats. Octane booster additives became popular for increasing the octane rating of gasoline used in the high-compression engines of the day. In most cases, a valve seat lubricant is included in an octane booster to reduce wear on antique and collector car engines equipped with cast-iron valve seats.  Fuel Injector Cleaners The symptoms of clogged fuel injectors are hard-starting, poor cold- engine performance and sluggish acceleration. These symptoms are caused by carbon deposits clogging the fuel injector nozzles. Most lower-priced fuel injector cleaners are designed as preventive maintenance additives while the higher-priced cleaners are designed to also remove heavy carbon deposits from cylinder heads, valves and pistons. Any of these additives generally perform well when used as directed.
  5.  Upper Cylinder Lubricants Varnish deposits and low-speed driving, early L-head or “flat head” gasoline engines often had problems with engine valves sticking in their valve guides. Light-viscosity, high-detergent upper cylinder oils were designed to be added to the fuel tank to help clean and lubricate sticking valves. Nowadays, sticking valves are rare and usually caused by insufficient oil clearance in the valve guide assembly. Nevertheless, many modern gasoline additives contain some type of upper cylinder lubricant to lubricate valve guides, seats and piston rings.  Anti-Gelling Additives Anti-gelling additives are added to the fuel tank to liquify the solidified paraffin wax or “gel” that forms in the fuel and clogs diesel fuel filters during sub-freezing temperatures. While modern diesels use heated fuel lines and filters to prevent gelling, anti-gelling additives might be required to improve cold-starting performance during extreme winter temperatures.
  6. Terminal and Cargo Fuel Additives Terminal and cargo additives include:  Antioxidants  Cold-flow  Conductivity Improvers  Metal Deactivators
  7.  Antioxidant The presence of highly olefinic cracked components can lead to short induction periods, darkening and gum formation. Antioxidants can improve the stability of these fuels and increase the blending options for the refiner. We offer two different types of antioxidant chemistry, phenylene diamines and alkylated phenols which can be used for both gasoline and jet fuel applications. Our customized solutions are developed based upon olefin content, storage conditions and fuel applications to deliver improved performance to:  Improve storage stability  Retard gum formation  Increase refiner blending options
  8.  Cold-Flow Improver You need a cost effective way to reduce the growth of wax crystals in your diesel, biodiesel and heating fuels to increase the yield and avoid plugging fuel filters. CFI additives were developed to protect against engine failure while providing blending and operational flexibility. These additives also improve the low-temperature handling properties of biofuels, petroleum fuels, residual oil and crude oils, positively affecting your refinery’s gross margins. Low temperature performance of middle distillates can be defined by these key properties:  Cloud Point: The temperature at which wax crystals are first visible; nucleation of wax crystals.  Cold Filter Plugging Point (CFPP): An indication of vehicle low temperature operability. At temperatures close to the cloud point, fuel system filters in vehicles become blocked.  Pour Point: The lowest temperature at which fuel will flow, interlocking wax crystal formation that prevents flow.
  9.  Static Dissipator When slow dissipation is an issue or low sulfur fuels are transported through distribution systems (like pipelines), the risk of fire or explosion hazard caused by static build- up and electro-static ignition increases. As fuels have become cleaner over the years, lower sulfur levels have increased these risks. The process used to remove polar compounds from low sulfur fuels reduces the ability of the fuel to dissipate a static charge. Dorf Ketal's Conductivity Improvers include a non- metallic range of Static Dissipator Additives (SDAs). At low concentrations (typically 0.5 to 2 mg/l), SDAs increase the electrical conductivity of middle distillates, reducing the risk of accidents.
  10.  Metal Deactivator One or more undesirable fuel reactions, such as a darkening of color, gum formation or sedimentation? You could be at risk of fuel degradation. Metal Deactivator is a proven, highly-effective solution for eliminating the catalytic effect trace dissolved concentrations of copper, vanadium and iron can have on fuel degradation. It works by chelating dissolved trace metals to reduce the catalytic process at its source. After assessing the level and nature of metal contamination present in the fuel, we will prescribe a customized solution using Metal Deactivator combined with a blend of antioxidants and a dosage rate developed specifically to meet the needs.
  11. Heating Fuel Additives  Thermal Stability Enhancer additives to enhance thermal stability of fuels at elevated temperature, and which can be accelerated by contact between heating fuel and metallic pipe work, are encountered in heating appliances. Enhance thermal stability ensures minimal fuel degradation prior to combustion, with optimum performance from the heating appliances.
  12.  Corrosion Inhibitor Corrosion inhibitor additives provide refiners and producers another tool to meet fuel specifications. Various types of metals are used such as mild steel, copper and silver, so corrosion inhibitors are appropriate for use in diesel, jet fuel or gasoline streams. Technically, these inhibitors adhere to the metal surface to form a hydrophobic barrier film which separates the metal and the fuel. The effectiveness of these inhibitors depends on the chemical composition, their molecular structure, and their affinities for the metal surface.
  13. Fuel Additives User Benefits The range of benefits to the user occuring from fuel additives is very significant and include:  Enhance safety Greatly reduced risk of static discharge, which can cuase fire and explosions  Cost saving 1. Protection of fuel tanks, pipelines and other equipments from expensive corrosion 2. reducing wear in moving parts
  14. END