Laboratory role in petroleum industry
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- Laboratory Role in petroleum industry By : Chem / Fouad Agamy Oil Lab Dept. Manager MIDOR Refinery Alex. Egypt
- What Is Quality? One definition which is accepted by experts in the field is : the degree of excellence or its ability to meet or exceed customer needs and expectations
- The operational techniques -such as testing in the laboratory- used to fulfil requirements for quality. Products have many properties. Only a few are needed to describe quality. Thus only a few tests are required to ensure that the product will meet customer quality requirements as well as meet government and industry specifications. What Is Quality Control (QC)?
- Why we need QC ? ( Laboratory Role) The overall function of the Laboratory Department Ensures appropriate quality control for refinery finished products and individual unit operations and provides necessary laboratory support for activities such as operations analysis.
- Performs routine testing of process and utility unit streams to monitor quality and unit performance. Performs routine testing to monitor blending operations and to certify finished product quality for shipment Why we need QC ? ( Laboratory Role)
- Performs necessary testing of line samples and compartment samples from ships and tank trucks to monitor potential contamination in loading operations. Performs necessary testing of purchased raw materials such as crude oil, natural gas, and delivered process chemicals. Why we need QC ? ( Laboratory Role)
- Performs routine testing to monitor performance of environmental control facilities, and the quality of water effluents. Collects routine samples from process units, tank farm and loading rack. Performs special sampling such as pressurised bomb samples, bladder and tube samples. Why we need QC ? ( Laboratory Role)
- Performs laboratory functions in support of operations analysis, troubleshooting unit problems, performance evaluation of equipment, catalysts and additives Provides technical and experimental service directed at solving plant operating or quality problems associated with the development of new products. Why we need QC ? ( Laboratory Role)
- Provides miscellaneous other laboratory services, including sample shipping for customer Why we need QC ? ( Laboratory Role)
- PRODUCT SPECIFICATIONS What Are Product Specifications? A product specification is a schedule of minimum performance requirements for a particular product. Each class of products, such as gasoline, jet fuels and Diesel fuels, has its own specification schedule.
- PRODUCT SPECIFICATIONS Why Are We Concerned With Specifications? It is always important to provide a product that is uniform in quality. The only way to ensure product uniformity is to establish requirements for a particular product and to ensure that every shipment or batch of that product conforms to those requirements. If product quality is not specified, one batch of product could be out of quality and be of no value for its end use. Also, another batch could be of higher quality than necessary for its end use, and in this case, the supplier would be giving away quality.
- PRODUCT SPECIFICATIONS How Are Product Specifications Defined? Product specifications are defined by the quality needed in a product in order for it to accomplish its purpose. Gasoline must meet certain criteria for volatility, and anti- knock quality, as well as other criteria. The specifications must include requirements so that the engine which will use this gasoline will start easily on cold days and run smoothly after it has started. These requirements must be carefully described in the specifications for the product.
- PRODUCT SPECIFICATIONS Other specifications are defined by storage conditions and shipping restrictions. For example, jet fuels must meet certain criteria for gum content and particulate contaminations. Specifications can also be influenced by environmental factors. Certain components which would be found in the natural state, such as sulphur in crude oil, would not be environmentally acceptable.
- PRODUCT SPECIFICATIONS Who Is Responsible For Product Specifications? The Manufacturer or Supplier The supplier would have a major interest in maintaining specifications on his product to provide a quality product and to supply a competitive product at a competitive price. The Customer or End User The customer sets specifications on the products he buys so that the product will perform at the levels he requires in his particular application. He contracts with the supplier to provide a product of a given quality or specification level.
- PRODUCT SPECIFICATIONS How Are Specifications Controlled? Specifications are controlled by performing a series of evaluations or tests on the products at various points in their manufacture or shipment. These tests are specially designed to define a particular characteristic of the product. The supplier can use the test results as a means to adjust his manufacturing conditions to produce a product of satisfactory quality. He can also use the results to correct the quality of batches of materials that do not conform to specifications and would, therefore, be unacceptable to his customer. The customer uses the specification tests to assure that the product he has received will perform as expected in his application. He may also use the tests to determine the quality of the product after it has been in storage for an extended period.
- PRODUCT SPECIFICATIONS Specifications are subject to much negotiation. In order to overcome many of the problems associated with a variety of tests to specify the same characteristic in a product, several Standards organizations have been established. These organizations are sponsored by those people who need standardized tests. The Standards organization compiles testing methods and standardizes them according to good statistical practices. These methods then become the standard against which specifications can be measured. Since the Standards organization has no direct connection with the suppliers or the end user, it enjoys a position of independence and integrity.
- PRODUCT SPECIFICATIONS The Standards organizations that are responsible for most of the methods used in the petroleum industry are American Society For Testing and Materials (ASTM) American Petroleum Institute (API) Institute of Petroleum (IP) Universal Oil Products (UOP)
- LPG Quality Control 1-Vapor Pressure ASTM D1267 measure of the amount of the most volatile material present in the product. It can also be used as a means for predicting the maximum pressures which may be experienced at fuel tank temperatures. Vapour pressure becomes more significant when it is related to volatility.
- LPG Quality Control 2- Volatility ASTM D 1837 Expressed in terms of the 95 % evaporated temperature of the product, is a measure of the amount of least volatile fuel component present in the product. Coupled with a vapor pressure limit, it serves to assure essentially single-component products in the cases of commercial propane and commercial butane fuel types. 3-Relative Density ASTM D1657 relative density is of importance in meeting transportation and storage requirements
- LPG Quality Control 4- Residue ASTM D2158 A measure of the concentration of soluble hydrocarbon materials present in the product which are substantially less volatile than the liquefied petroleum gas. 5- Copper Corrosion ASTM D1838 Limits are for the purpose of providing assurance that difficulties will not be experienced in the deterioration of the copper and copper-alloy fittings and connections which are commonly used in many types of utilization, storage, and transportation equipment. The copper corrosion test will detect the presence of hydrogen sulfide, which is highly toxic. The copper corrosion limits also provide assurance that the LP-Gas will not contain H2S in such quantities as to present a health and safety hazard.
- Crude Oil Quality Control 1- Density ASTM D 5002 or ASTM D 1298 (Hydrometer) Density : is the mass of liquid per unit volume at 15C Relative density or specific gravity is the ratio of the mass of a given volume of liquid at 15C to the mass of an equal volume of pure water at the same temperature . API gravity ( degree ) = 141.5 / (sp gr 60/60F) - 131.5
- Crude Oil Quality Control Density according to ASTM D 1298 The sample is brought to the specific temperature and transferred to a cylinder at approximately the same temperature . The appropriate hydrometer is lowered into the sample and allowed to settle and after temperature equilibrium has been reached , the hydrometer scale is read and the temperature of the sample recorded . The density is converted to standard temperature 15C by means of standard tables 53A for crude or 53B for petroleum products or 53D for lube oils . Report density @ 15C = XXX.X kg / m3 or 0.XXXX g / ml
- Crude Oil Quality Control Density according to ASTM D 5002 Approximately 0.7 ml of crude is introduced into an oscillating tube and change in oscillating frequency caused by change in mass of the tube is used in conjunction with the calibration data to determine the density of the sample . Report density @ 15C = XXX.X kg / m3 or 0.XXXX g / ml
- Crude Oil Quality Control 2- Salt Content ASTM D 3230 This method measures conductivity due to presence of inorganic chlorides and other conductive material in the crude . The sample is dissolved in mixed alcohol solvent and placed in a test cell consisting of a beaker and two parallel stainless steel plates ( electrodes ) . A voltage is impressed on the electrodes and the resulting current flow is measured .And the salt content is obtained by reference to a calibration curve of the relationship of salt content of known mixtures to the current . Range 0 -- 150 PTB ( Ib/1000bbl ). 1PTB = 2.86 ppm Report to the one decimal , XX.X PTB
- Crude Oil Quality Control 3- Bottom sediment and water (BS& W by) centrifuge ASTM D 4007 Known volumes of crude and saturated toluene are placed in a centrifuge tube and heated at 60C . After centrifugation , the volume of sediment and water layer at the bottom of the tube is read .The amount of water detected is always lower than the actual water content . For most accurate water content results use ASTM D 4006 and ASTM D473 for accurate sediment content results. Report BS&W to the nearest 0.025 vol%
- Crude Oil Quality Control 4- Water by distillation ASTM D 4006 ( Dean & Stark ) The crude sample is heated in 1000 ml round bottom distillation flask under reflux conditions with a water immiscible solvent ( xylene ) which co-distills with the water in the sample . Condensed solvent and water are continuously separated in the trap , the water settles in the graduated section of the trap and the solvent returns to the distillation flask . Report to the nearest 0.025 % vol
- Crude Oil Quality Control 5- Sediment content by Extraction method ASTM D 473 Range 0.01 --- 0.40 % mass The crude sample in a refractory thimble is extracted with hot toluene until the residue reaches a constant mass . Report to the nearest 0.01 mass % 6-Sulfur by wave energy dispersive X- ray ASTM D 4294 Range 0.015 --- 5.0 % mass The sample is placed in a beam emitted from an X-ray source . the resultant excited characteristics X radiation is measured and the accumulated count is compared with counts from previously prepared calibration standard to obtain the sulfur concentration . This method can be affected by some present interferences such as halides if present at concentrations greater than one tenth of the measured S . Report to the three decimal , X.XXX mass %
- Crude Oil Quality Control 8-Pour point ASTM D 97 Manual method After preliminary heating , sample is cooled at a specified rate and examined at intervals of 3C for flow characteristics . The lowest temperature at which the movement of the oil is observed is recorded as the pour point . Crude oil with a high wax content presents difficulties in handling and pumping . 9- Asphaltenes content By membrane filtration UOP 614 ( Heptane insoluble ) A quantity of crude ( 1.5 gm ) is dissolved in n heptane and filtered by vacuum pump through filter membrane 5.0 um pore size , 47 mm diameter . The filter with residue is washed , dried and weighed to give the asphaltenes content . Report to two decimal X.XX % mass
- Crude Oil Quality Control 10-Kinematic viscosity ASTM D445 Viscosity is usually determined at different temperatures ( 25C , 40C & 100C ) by measuring the time in seconds for a volume of liquid to flow under gravity through a calibrated glass viscometer at controlled temperature. Kinematic viscosity Cst = measured flow time in seconds X calibration constant of viscometer Report to three decimal ,kinematic viscosity at 100F = X..XXX Cst
- Crude Oil Quality Control 11-Micro carbon residue ASTM D4530 Range 0.01 -- 30 % mass. Aweighed quantity of sample ( 0.5 1.0 gm ) is placed in small glass vial and heated to 500C under inert nitrogen atmosphere in a controlled manner for a specific time The sample undergoes coking reactions , and volatiles formed are swept away by the nitrogen And the carbonaceous residue is reported as % w/w of the original sample . Report to two decimal X.XX % mass
- Crude Oil Quality Control 12- Acid number by potentiometric titration ASTM D664 Is a measure of the inorganic and total acidity and indicates its tendency to corrode metals which it may contact . Acid number : is the quantity of base , expressed in mg KOH / gm of sample , that is required to titrate a sample to a meter reading corresponding to a freshly prepared aqueous basic buffer solution ( pH = 11 ) or to defined inflection point . The sample (20 gm) is dissolved in a mixture of toluene and isopropyl alcohol containing a small amount of water and titrate potentiometrically with alcoholic KOH using a glass indicating electrode and calomel reference electrode to inflection point or to a freshly prepared aqueous basic buffer solution ( pH = 11 ) . Report to the two decimal X.XX mg KOH / gm
- Crude Oil Quality Control 13- Aniline point ASTM D 611 It is used to estimate the aromatic content of mixtures and can be used to determine the aromatic or aliphatic character . Aromatics exhibit the lowest aniline points and paraffins the highest aniline point. Cycloparaffins and olefins exhibit values between these two extremes . Report the result to the nearest 0.1 C .
- Crude Oil Quality Control 14 - Nitrogen content The Nitrogen causes serious environmental problems , in addition to the basic character of the nitrogen neutralizes catalyst acidity. These are transformed into ammonia by reaction with H2. The amount of nitrogen in the feed stock determines the severity of the process particularly the temperature and causes more rapid catalyst deactivation and decrease the life time of catalyst , and the H2 requirements and the sediment formation and deposition like ammonium bisulfide salt. Nitrogen can cause color stability problems in the jet fuels . Total Nitrogen content ASTM D 4629 ( Antek ) Range 0.3 -- 100 mg / kg The diluted crude sample is introduced by syringe into the stream of argon . The sample is vaporized and carried to a high temperature zone where the oxygen is introduced and organically bound nitrogen is converted to nitric oxide NO . The NO contacts ozone ( O3 ) , and is converted to excited nitrogen oxide NO2 . The light emitted as the excited NO2 decays is detected by a photomultiplier tube and the resulting signal is a measure of the nitrogen contained in the sample . Report to one decimal XX.X mg/kg .
- Crude Oil Quality Control 15-Metals content Causing corrosion and affect the quality of refined products and deactivate ( reduce catalyst activity ) or poison the catalysts. vanadium can form low melting compounds such as vanadium penta oxide which melts at 691 o C and cause sever corrosion attack on the entire high-temperature alloy used for gas turbine sodium and potassium can combine with vanadium to form eutectics which melt at 565 o C and with sulfur in the fuel to yield sulfates . These compounds produce severe corrosion for turbines. Metals test methods V, Ni, Na , Fe , Ca , Al , Mg , Si , by wet ashing or by organic solvent and then by atomic absorption spectrophotometric method ASTM D5863 or UOP 391 or by wet ashing or by organic solvent and then by ICP ASTM D5708 or by UOP389.
- Gasoline Quality Control 1- Density ASTM D 4052 or ASTM D 1298 (Hydrometer) The density of a material is defined as its mass per unit volume Used for weigh-volume calculation and to characterize the volatility of gasoline Used for heat combustion calculation Report density @ 15 o C = XXX.X kg / m3 or 0.XXXX g / ml Specification 720.0 - 775.0 Kg/M3 2- Appearance Clear & bright free from water and particulate contamination
- 3-Distillation ASTM D86 ( Volatility characteristics ) Volatility of a liquid is its tendency to change from the liquid to vapor IBP range (35 40 o C) 10 % , 65 o C max should be low enough to ensure starting under normal condition and must be sufficiently volatile to give easy starting, rapid warm up 50% range (77-115 o C) indicates the performance of gasoline combustion 90% max 180 o C E.P max 215 o C indicates the amount of heavy H.C in gasoline and cause poor mixture distribution in tank and combustion chamber, increased H.C emission, increased chamber deposit and dilution of the crankcase oil report I.B.P,10%.50%,90%,E.P,residue %volume max 2% , low or high residue indicate the absence or presence high boiling compounds Gasoline Quality Control
- 4- Vapor pressure It's the force exerted on the walls of closed container by the vaporized portion of liquid ASTM D5191 (mini method) , ASTM D4953 (dry method) Specification in summer (mar-oct) 0.4 - 0.63 bar in winter (nov-feb) 0.4 - 0.7 bar the vapor pressure of gasoline must be sufficiently high to ensure ease of engine starting but it must not be high to avoid vapor lock (that vapor if formed in gasoline line that impede the flow of gasoline to the carburetor) and to avoid vapor losses from gasoline tanks during storage and transportation. Gasoline vapor pressure depends on its butane content The vapor pressure increases with increase in temperature . report V.P to the nearest 0.01 bar Gasoline Quality Control
- 5- Sulfur (HOUSTON ATLAS) ASTM D4045 (ANTEK) ASTM D5453 specification 10 mg/kg max to protected engine from wear, deterioration of engine oil and corrosion of exhaust system parts combustion may be converted to acid that promote rusting and corrosion of engine parts report X.XX mg/kg 6- Total Aromatics ASTM D 1319 42.0 vol % maximum In order to reduce the ozone reactivity and toxicity of automotive evaporative and exhaust emissions Aromatics HC having the highest solvent power (unsuitable for some aircraft engine seals, gaskets and some fuel tank materials like elastomer could be affected) and the straight chain aliphatic HC is the lowest Gasoline Quality Control
- 7- Benzene content by GC 1.0 vol % maximum In order to reduce the ozone reactivity and toxicity of automotive evaporative and exhaust emissions 8- Olefins content ASTM D1319 18.0 vol % maximum It is may oxidize during storage and form undesirable oxidation products ( gum formation ) Is required to comply with government regulations Gasoline Quality Control
- 9- Octane number (knock rating) Octane number is a measure of a gasoline antiknock performance , its ability to resist knocking as its burn in the combustion chamber RON (research octane number) ASTM D2699 MON (motor octane number) ASTM D2700 Antiknock rating of a fuel is a measure of its resistance to knock . A decrease in antiknock rating may cause vehicles performance loss, loss of power , objectionable noise and engine damage . Specifications RON 95 min MON 87 min Octane is measured relative to a mixture of iso-octane (2,2,4- trimethylpentane, an isomer of octane) and n-heptane. An 95- octane gasoline, for example, has the same octane rating as a mixture of 95 vol-% isooctane and 5 vol-% n-heptane. This does not mean, however, that the gasoline actually should contain these chemicals in these proportions. It simply means that it has the same antiknock resistance as the described mixture. Gasoline Quality Control
- 10 - Gum content ASTM D381 specification , solvent washed gum content 5mg/100ml max gum can cause induction system deposits and sticking of intake valves and carburetors indicates the contamination by higher boiling oils or particulate matter report to the nearest 0.5 mg/100ml solvent washed gum content, unwashed gum content the heptane wash, removes additives , non volatile oils and heavy hydrocarbons such as diesel fuels the difference between the unwashed and solvent washed gum content can be used to assess the presence of non volatile material in the fuel The potential gum is determined by accelerated gum test ASTM D873 which is used for safeguard of storage stability and can predict the potential for gum formation during prolonged storage Gasoline Quality Control
- 11- Induction period (oxidation stability) ASTM D525 specification > 480 min indication of the tendency of motor gasoline to form gum in storage gasoline instability can be related to the hetero atoms containing (N, O, and S) and olefins compounds during storage gasoline can oxidize slowly in the presence of air and form peroxides and gum, soluble in gasoline but the gum may appear as a sticky residue on evaporation these residues can deposit on carburetor , fuel injectors automotive fuels usually have very low gum content when manufactured but may form gum during extended storage Most of automotive gasoline contains Antioxidants additives ( Metal deactivators ) to prevent oxidation and gum formation 12- Lead content IP 224 specification 0.013 gm /L (13 mg/L) maximum lead for environmental regulations Gasoline Quality Control
- Jet A-1 Quality Control 1- Density ASTM D 4052 The density of a material is defined as its mass per unit volume Used for weigh-volume calculation and in calculation of specific energy when used with other parameters such as aniline point, distillation, sulfur, Aromatics. Report density @ 15 o C = XXX.X kg / m3 or 0.XXXX g / ml Specification 750.0 - 840.0 Kg/M3 2- Appearance ASTM D 4176 Visual appearance clear & bright and visual free from solid matter and un dissolved Water at ambient temperature. Un dissolved water (free) ASTM D 3240 can encourage the growth of microorganisms and corrosion in the aircraft tanks and also leads to icing of filter in the fuels system Report C & B = clear and bright
- Jet A-1 Quality Control 3- Color ASTM D 156 (saybolt) or ASTM D 6045 (automatic) Color can be useful indicator of fuel quality, darkening of fuel or a change in fuel color may be the result of product contamination or instability (gum formation) Color range colorless to straw/pale yellow +16 min Report + XX 4- Particulate contamination (ASTM D 5452) Provides field quality control of dirt and rust which leads to filter plugging. max 1.00 mg/L Repot X.XX mg/l
- Jet A-1 Quality Control 5- Total acidity ASTM D3242 Total acidity =weak acid (organic acid) + inorganic acid (mineral acids) Tendency of the fuel to corrode metals that it contacts , acidity reduces the WSIM of the aviation turbine fuel Naphthenic acid + NaOH or (NH4OH) sodium or ammonium naphthenate Sodium or ammonium naphthenate (surfactants) = surface active impurities soluble In water and soluble in HC ,allow the water and particulate to pass through fuel filter system. Report 0.XXX mg KOH/gm & max 0.015 mg KOH / gm 6- Aromatic ASTM D1319 Indicates the combustion properties of jet fuel The amount of aromatics are limited 25 % volume maximum because the combustion of aromatics can cause smoke and carbon or soot deposition which can affect the life of combustion chamber Paraffines > naphthenes > aromatics in combustion quality olefins have good combustion quality but poor gum stability Report XX.X% vol max 25 % vol
- Jet A-1 Quality Control 7- Total sulfur ASTM D4294 Sulfur compounds affect the fuel performance in the combustion chamber - Sulfur oxides formed during combustion may be corrosive to turbine metal parts Report 0.XX % mass max 0.30 % mass 8- mercaptan sulfur ASTM D3227 Mercaptan are reactive with certain elastomers ( polymer ) and corrosive to fuel system metals unpleasant odor Report 0.XXXX %mass Max 0.0030 % mass 9- Flash point ASTM D 56 (Tag) Indicates the fuel handling and safety precautions Indication of the maximum temperature for fuel handling and storage without serious fire hazard Report to nearest 0.5 o C min 40 o C
- Jet A-1 Quality Control 10- Freezing point ASTM 7153 Indicates the fuel Fluidity at low temperature The long duration flights requires lower freezing point than short duration flights. The maximum freezing point are set for all types of aviation fuel as a guide to the lowest temperature at which the fuel can be used without risk of solidification of hydrocarbons that can restrict the flow of fuel through filter system Wax and high end point affect the freezing point . Report XX.X o C max. -47 o C 11- Viscosity @ -20 o C ASTM D 445 Indicates the fuel Fluidity at low temperature Viscosity is related to pump ability over temperature range to ensure the fuel injection nozzles and system controls will operate down to design temperature. The ability of fuel to lubricate a pump may also relate to the viscosity. Report XX.X cSt Maximum 8 cSt (mm2 /s). 12 - Smoke point ASTM D1322 Indicates the combustion properties of jet fuel Indication of relative smoke producing properties of jet fuel and its related to the hydrocarbon type composition of such fuels-More aromatic have low smoke point and high smoke point indicates a fuel of low smoke properties tendency. Smoke point is inversely proportional to the Aromatics content of fuel. Report XX.X mm minimum 25 mm
- Jet A-1 Quality Control 13- Distillation ASTM D86 Indicates fuel volatility and ease of vaporization at different temperatures (Fuel Atomization) IBP ------------------------------------------- relationship with flash point 10% ------------------------------------------indication of volatile HC to ensure easy starting max. 205 oC 50% ----------------------------------------- stabilization of fuel and it is not consists of low boiling point and high boiling point component only. 90 % ----------------------------------------- indication of heavy components which difficult to vaporize E.P max 300 oC 10% & 50% & 90% used for specific energy calculation IBP and 10% effect on the flash point and ease of ignition 50% is more relative to viscosity E.P is indication of heavy materials that give poor fuel vaporization and affect on engine combustion performance Report XXX.X oC Residue x.x %vol 1.5% max Loss x.x %vol 1.5% max 14 - Naphthalene ASTM D 1840 Indication of combustion characteristic of jet fuel because naphthalene when burned tend to sooty flame, smoke and thermal radiation than single ring aromatics.
- Jet A-1 Quality Control 15- Copper corrosion ASTM D 130, 2 hours @100 o C To ensure that the jet fuel will not corrode copper or any copper base alloys in various parts of the fuel system max 1b 16- Silver corrosion IP227, 4 hours @50 o C To ensure that the jet fuel will not corrode silver or any silver base alloys in various parts of the fuel system max 1
- Jet A-1 Quality Control 17-WSIM ASTM D 3948 Measure the ability of fuel to separate water through fiber glass coalescer. Provides a measure of the presence of surface active materials (surfactant) High rating indicates the water is easily coalesced (clay filter used in kerosene merox U-06 to remove surfactant) and fuel is free of surfactant materials Surfactants is surface active material that exhibit both water soluble and oil soluble properties and affect the water oil separation by forming emulsions. Report whole number XX min 70 with SDA min 85 without SDA 18- Electrical conductivity ASTM D 2624 Indicates the static electricity The ability of fuel to dissipate charge that has been generated during pumping and transportation. Electrical conductivity depends on ion species If the conductivity is high charge dissipate fast enough to prevent their accumulation and dangerous high potentials in receiving tank are avoided Report whole no PS /m @ temperature o C Range 50 - 600 PS/M
- Jet A-1 Quality Control 19- Thermal oxidation stability JFTOT ASTM D 3241 Its the ability of fuel to withstand relatively high temperature for short periods of time in presence of oxidation and without deposits and coke formation or deterioration of properties (Degradation) Indicative of fuel performance during gas turbine operation and can be to assess the level of deposits that form when liquid fuel contacts heated surface Report temperature 260 o C p whole no mmHg spec max 25mmHg heater tube deposit rating spec < 3 max 20- Existent gum IP 540 Indicates the fuel storage stability existent gum is a non volatile residue left after evaporation of fuel Gum formation leads to peroxides formation which affects the certain elastomers in the fuel system. Indication of storage stability of fuel because unstable fuels oxidize and form polymeric oxidation products (gum) which remain as resinous solid on carburetor valve ,large quantities of gum are indicative of contamination of fuel by higher boiling point oils or particulate matter -the existent gum value is the gum actually present in the fuel at the time of test and is measured as the weight of residue obtained of controlled evaporation of standard volume of fuel Unsaturated H.C (olefins) and hetero cyclic atoms (S, N, O) are relatively unstable and gives rise to excessive gum formation The storage stability is the ability of fuel to remain in storage over extended period of time without gum formation (sticky residues) or sediment formation. The accelerated test ASTM D 873 is a safeguard of storage stability and predicts the possibility of gum forming during protected storage and decomposition of Anti Knock additives. The fuel is heated for 16 hours with oxygen under pressure in a bomb at 100 C and then the both gum content and amount of precipitate are determined. Report whole number to the nearest 1 mg /100ml max 7 mg/100ml
- Diesel Quality Control 1- Density ASTM D 4052 Range 820.0 870.0 Kg/M3 2- Color ASTM D 1500 Indication of product contamination by high boiling point components max 4.0 Report X.X 3-Appearance particulate (rust & sand and dirt) effect in filter of fuel system Visual Report clear & bright (free from free water and particulate)
- Diesel Quality Control 4- Flash point ASTM D 93 for safety precautions during fuel and storage A flash point that is too low will cause fuel to be a fire hazard and may indicate contamination by more volatile component such as jet fuel min 55.0 o C Report to nearest o C 5- Kinematic viscosity @ 40.0 o C ASTM D 445 Viscosity of diesel is important because it's affected on the handling of the fuel by the pump and injector system A high viscosity can result in poor atomization forming a spray pattern of large droplets. As the result the fuel is not distributed in, mixed with air required for burring, poor combustion is a result and loss of power and economy High viscosity causing dilution of the crankcase oil. low viscosity can produce too soft spray and combustion is reduced and power out put and economy are decreased Specification 2 6 cSt @ 40.0 o C Report X.X
- Diesel Quality Control 6- Distillation (volatility) ASTM D 86 The volatility requirement of diesel fuel varies with engine speed, size and design. Fuels having too low volatility tend to reduce power out put and fuel economy through poor atomization. Fuel having too high volatility may reduce power out put and fuel economy through vapor lock in the fuel system The distillation range should be low as possible without affecting the flash point. Burning quality, heat content and viscosity If the 10% is too high, poor starting may result An excessive boiling rang from 10-50% evaporated may increase warm up time The temperature for 50% evaporated is known mid-boiling point and usually is taken as an overall indication the fuel distillation characteristics High temperature @50% cause smoke formation and objectionable odor ,cause lubricating oil contamination and promote engine deposits low temperature @ 50% would have too low a viscosity and heat content per unit volume low 90% and F.B.P tend to ensure low carbon residue and minimum crankcase oil dilution. The evaporated @ 350o C should be 85% to ensure the fuel contains easily sprayed distillates in fuel engine.
- Diesel Quality Control 7- Centane number ASTM D613 The percentage by volume of normal cetane [hexadecaneC16H34] (cetane no= 100) is blend with heptane methyl nonane (cetane no = 15) Cetane number for high speed diesel engines in the range of 45 55 cetane number Higher the cetane number tend to result in easier starting particularly in the cold weather, and faster warm up and small amount combustion chamber deposits and reduced exhaust smoke and a dour Cetane number (C.N) indicates the ability of a diesel engine fuel to ignite quickly after being injected into the cylinder The higher cetane number the more easily the fuel can be ignited and have shorter ignition delay periods than the lower cetane number There is no performance or emission advantage when the cetene number > 55 Alkyl nitrates and di-tertbutyl peroxides are used as additives to raise the cetane number cetane number 1/ignition delay Paraffins > isoparaffins > olefins > naphthene > aromatic > poly aromatics C.N decrease Specification 50 minimum Report whole number
- Diesel Quality Control 8-Cetane index ASTM D976 Cetane index 2 = cetane number Specification min 48 Report XX.X 9- Carbon residue ASTM D4530 Carbon residue is the amount of carbonaceous residue remaining after thermal decomposition of fuel give an indication of the amount of coke that will be formed during thermal process and amount of high boiling compounds in the fuel 0.1 % mass maximum on 10% residue Report to the nearest 0.1% mass
- Diesel Quality Control 10- Ash content ASTM D 482 ash is the inorganic residue (metals) remains after burning off carbonaceous matter. Report X.XXX mass % 0.01 % mass maximum 11- Pour point ASTM D 5950 The pour point of a fuel is an indication of the lowest temperature at which the fuel can be pumped Max zero o C Report multiples of 3C. 12 -Cloud point (wax appearance point) ASTM D 5771 cloud point is the importance in that it define the temperature at which a cloud or haze of wax crystals appears in the oil under test conditions and related also to the temperature at which wax crystals begin to precipitate from the oil in use specification 5 o C maximum 13 -Cold filter plugging point C.F.P.P ASTM D 6371 C.F.P.P is suitable for estimating the lowest temperature at which diesel fuel will give trouble free flow in certain fuel systems Pour point ------ C.F.P.P ----- cloud point 5o C ------ 1o C ----- 0 o C
- Diesel Quality Control 14- lubricity ASTM D 6079 lubricity is qualitative term describing the ability of a fluid to affect friction between, and wear to surfaces in relative motion under load Wear is damage to solid surface and loss of material due to relative motion between that surface and a contacting substance Diesel fuel functions as a lubricant in certain items of fuel injection equipment such as rotary distributor fuel pumps and injectors. In limited cases fuel with very specific properties can have insufficient lubricating properties which can lead to a reduction in the normal services life of fuel pumps or injectors. specification 520 micron max Report wear scar diameter (WSD) to the nearest 10 m 17- Sulfur ASTM D 4294 sulfur cause wear and deposits on engine and can affect emission control systems performance Maximum 0.200 mass % Report X.XXX mass %