Water residual fuel

Composition - Distillate fuel oils are similar to diesel oil. Residual fuel oil consists of semi-liquid phase with dispersed solid or semi-solid particles (asphaltenes, minerals and other leftovers from the oil source, metallic particles from the refinery equipment, and some dumped chemical wastes), plus some 0.5% water. Residual fuel oil leaves a carbonaceous residue in the tanks and may have up to 5% of sulfur. Residual fueloil-C (or bunker-C) has a composition of 88%wt C, 10%wt H, l%wt S, 0.5%wt H O,... 

Heat of combustion can be estimated within 1 percent from the relative density of the fuel by using Fig. 27-3. Corrections for water and sediment must be apphed for residual fuels, but they are insignificant for clean distillates. 

The need for heating, water washing, and the use of additives must be addressed when moving from the distillates toward the residuals. Fuel contaminants such as vanadium, sodium, potassium, and lead must be controlled to achieve acceptable turbine parts life. The same contaminants also can be introduced by the inlet air or by water/steam injection, and the combined effects from all sources must be considered. 

Sediment usually consists of finely divided solids that may be dispersed in the oil or carried in water droplets. The solids may be drilling mud or sand or scale picked up during the transport of the oil, or may consist of chlorides derived from evaporation of brine droplets in the oil. In any event, the sediment can lead to serious plugging of the equipment, corrosion due to chloride decomposition, and a lowering of residual fuel quality. 

In electric utilities, residual fuel oils, such as no. 4, have been used to process steam for electric plants (lARC 1989). Fuel oil no. 4 has been used in commercial and industrial burner installations that are not equipped with preheating facilities (Air Force 1989). In other industries, such as the maritime industry, plants and factories, and the petroleum industry, residual fuel oils have been used for space and water heating, pipeline pumping, and gas compression, as well as in road oils, and in the manufacture. 

Catalyst fines, metals, rust, sand, and other material can be contained in residual fuel. These compounds arise from the crude oil, processing catalysts, water contamination, transportation, and storage of the fuel. If the total ash content is >0.20 wt%, deposits can form in burner systems and corrosion in high-temperature burners can occur. 

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%. 

Burning of sulfur to produce SO can create both burner system corrosion problems as well as atmospheric air emission concerns. About 1% to 5% of the fuel sulfur burned is converted to S03 and the remainder is converted to S02. If a system operates below its dew point, the SO, can react with condensed water to form sulfuric acid. Much work is being done through hydrodesulfurization, neutralization, and engineering to reduce the amount of sulfur oxides produced through burning of residual fuel. 

Both oil-soluble and water-soluble chemical scavengers can be added to fuel to remove hydrogen sulfide from oil and from water that may be contained in the fuel. Method ASTM D-5705 has been developed to help identify the presence of hydrogen sulfide in residual fuel oil. 

Fuel-water emulsion technology has been utilized for several years to improve the combustion properties of heavy residual fuel oils. In the high-temperature combustion environment, water droplets that are finely dispersed in fuel begin to boil and explode into vapor within the fuel drops. As a result, a highly atomized... 

British Thermal Unit (BTU) A measure of the quantity of heat required to raise the temperature of 1 lb of water 1°F. For fuels such as gasoline, kerosene, fuel oil, and residual fuels, the following formulas can be used to determine the BTU/lb ... 

The third way of coal pipelining intensification supposes using the carrier liquid different than water. Oil products (crude oil, residual fuel oil, kerosene, fuel or Diesel oil and various mineral oils) or hydrocarbons (methanol, ethanol, carbonic acid, and other liquid organic compositions) can be used as a carrier liquid. 

Kawahara [21] has discussed the characterisation and identification of spilled residual fuel oils on surface water using gas chromatography and infrared spectrophotometry. The oily material was collected by surface skimming and extraction with dichloromethane, and the extract was evaporated. Preliminary distinction between samples was made by dissolving portions of the residue in hexane or chloroform. If the residue was soluble in chloroform but not in hexane it was assumed to be crude oil, a grease, a heavy residual fuel oil or an asphalt if it was soluble in both solvents it was assumed to be very light or heavy naphtha, kerosine, gas oil, white oil, diesel oil, jet fuel, cutting oil, motor oil or cutter stock. The residue was also examined by infrared spectrophotometiy wavenumber values of use for identification purposes are tabulated. 

Vanadium was discovered in 1830. It is present at 0.01% in earth s crust. Vanadium is released naturally into the air through the formation of continental dust, marine aerosols, and volcanic emissions. The natural release of vanadium into water and soils occurs primarily as a result of weathering of rocks and soil erosion. Anthropogenic sources include the combustion of fossil fuels, particularly residual fuel oils, which constitute the single largest overall release of vanadium to the atmosphere. Deposition of atmospheric vanadium is also an important source... 

Type C crude oils. These are viscous and sticky, tarry brown products and flushing will not remove them from surfaces. Their density is close to water and some will sink to the bottom. Their toxicity is low and includes some residual fuel oils blended as medium to heavy crude. 

Exposure Levels in Environmental Media. Vanadium levels in environmental media are reasonably well documented although more recent information would enable a more accurate assessment of potential exposure levels (Byerrum et al. 1974 Byrne and Kosta 1978 Van Zinderen Bakker and Jaworski 1980 Waters 1977 WHO 1988 Zoller et al. 1973). Current information on emission levels from the combustion of residual fuel oil would enable a more complete picture of populations potentially exposed to higher than background ambient air levels. Further studies on the levels and forms of vanadium found in food would be helpful in narrowing the range of values observed. This would allow a better estimation of dietary exposure. Moreover, information concerning levels found in environmental media in the vicinity of hazardous waste sites would be particularly useful. 

The calorific value (heat of combustion) of residual fuel oil (ASTM D-240, IP 12) is lower than that of lower-boiUng fuel oil (and other liquid fuels) because of the lower atomic hydrogen-to-carbon ratio and the incidence of greater amounts of less combustible material, such as water and sediment, and generally higher levels of sulfur. 

Contamination in residual fuel oil may be indicated by the presence of excessive amounts of water, emulsions, and inorganic material such as sand and rust. Appreciable amounts of sediment in a residual fuel oil can foul the handling facilities and give problems in burner mechanisms. Blockage of fuel hlters (ASTM D-2068, ASTM D-6426) due to the presence of fuel degradation products may also result. This aspect of fuel quality control may be dealt with by placing restrictions on the water (ASTM D-95, IP 74), sediment by extraction (ASTM D-473, IP 53), or water and sediment (ASTM D-96, IP 75) values obtained for the fuel. 

The Karl Fischer test method (ASTM D-1364, ASTM D-6304) covers the direct determination of water in petroleum products. In the test, the sample injection in the titration vessel can be performed on a volumetric or gravimetric basis. Viscous samples, such as residual fuel oil, can be analyzed with a water vaporizer accessory that heats the sample in the evaporation chamber, and the vaporized water is carried into the Karl Fischer titration cell by a dry inert carrier gas. 

Water and sediment can be determined simultaneously (ASTM D-96, ASTM D-1796, ASTM D-4007, IP 75, IP 359) by the centrifuge method. Known volumes of residual fuel oil and solvent are placed in a centrifuge tube and heated to 60°C (140°F). After centrifugation, the volume of the sediment and water layer at the bottom of the tube is read. In the unlikely event that the residual fuel oil contains wax, a temperature of 71°C (160°F) or higher may be required to completely melt the wax crystals so that they are not measured as sediment. 

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