Determination of diesel oil in Suzhou diesel
Release date: 2016-12-20
Determination of diesel oil in Suzhou diesel
test methodsOxidationAccording to SH / T0175 method for determinationMethod Summary: 350mL of the filtered sample, into the oxidation tube, into the oxygen, the rate of 50mL / min at 93 ℃ temperature oxidation 16h. The oxidized sample was then cooled to room temperature and the resulting filterable insoluble material was filtered. The adherent insoluble matter was washed off from the oxidation tube with a triad mixture, and the three-component mixture was evaporated to remove the adherent insoluble matter. The sum of the insoluble matter and the adherent insoluble matter can be filtered as the total amount of insoluble matterSulfur contentAccording to GB / T 380 method for determinationMethod Summary: the amount of samples in the lamp combustion, with 0.3% sodium carbonate aqueous solution to absorb the combustion of sulfur dioxide, and 0.05N hydrochloric acid standard solution titration absorbance, with bromocresol green red as the titration indicatoracidityAccording to GB / T 258 method for determinationMethod summary: Volumetric method, this method is the use of boiling ethanol out of light diesel oil in the organic acid, and then hot with 0.05N potassium hydroxide ethanol solution titration, and 100 ml of petroleum products required for the number of milliliters of potassium hydroxide For the acidityCetane numberAccording to GB / T 386 method for determinationThe cetane number refers to the volume fraction of n-hexadecane contained in the standard fuel equivalent to the diesel self-ignitability. The standard fuel is a mixture of n-hexadecane and 2-methylnaphthalene in different volume percentages. Among them, n-hexadecane has good self-ignitability, and its cetane number is set to 100, and α-methylnaphthalene (1-methylnaphthalene) is poor in self-ignitability. Methylnaphthalene (1-methylnaphthalene) was replaced by 2,2,4,4,6,8,8-heptamethylnonane, and the cetane number was set to 15, and the cetane number was determined Is in the laboratory standard single cylinder diesel engine according to the stipulation condition carries on. Cetane high diesel easy to start, burning evenly, the output power; low cetane, then the fire is slow, unstable, prone to knock. Generally used for high-speed diesel engine light diesel oil, the cetane number to 40-55 is appropriate; medium and low speed diesel engine with the cetane number can be as low as 35 or less. The cetane number of diesel oil is related to its chemical composition. The n-alkane has the highest cetane number, the lowest cetane number of aromatics, and the isoparaffin and cycloalkane center. When the cetane number higher than 50, and then continue to improve the role of shortening the ignition delay of diesel fuel is not; the contrary, when the cetane number higher than 65, because the ignition delay is too short, the fuel and air Uniform combustion that spontaneous combustion, resulting in incomplete combustion, part of the thermal decomposition of hydrocarbons produced free carbon particles, with the exhaust emissions, resulting in engine black smoke and increased fuel consumption, power decline. Additives can improve the cetane number of diesel, commonly used additives are amyl nitrate or ester.Residual carbonAccording to GB / T 268 method for determinationMethod summary: the appropriate amount of sample placed in the crucible for decomposition and distillation, the residue is heated to cracking and coking reaction in the heating 30 ± 2 minutes later, the quality of carbon residue calculated by the residual carbon contentAshAccording to GB / T 508 method for determinationMethod Summary: A sample of not more than 100 g was placed in a crucible with constant weight, heated with a hot plate, and the ashless filter paper was used as the ignition core to burn ash and carbon residue to 775 ± 25 ℃ high temperature furnace for 1.5 to 2 hours, by weighing the ash results.Flash pointAccording to GB / T 261 method for determinationSummary of the method: The sample is heated at a constant, slow rate with continuous agitation. A small flame is introduced into the cup at a specified temperature interval, with the interruption of agitation. The minimum temperature at which the test flames cause a vapor flash on the specimen is the flash point. 10, 5, 10, -20 diesel has a closed flash point of 55 ° C, -35 and -50 diesel oil is 45 ° C.  densityAccording to GB / T 1884 and GB / T 1885 method for determinationThe density of 0 # diesel oil in the standard temperature of 20 ℃, usually 0.84--0.86g / cm ³ between.Summary of the method: the sample at a specified temperature, pour it into the density of the same density measuring cylinder, the appropriate density meter into the sample has been adjusted temperature, let it stand still. When the temperature has reached equilibrium, read the densitometer readings and the sample temperature. The observed densitometer readings were converted to standard density using a petroleum meter.Freezing pointAccording to GB / T 510 method for determinationSolidification point is an important indicator of the assessment of diesel fluidity, which indicates that the fuel can not be heated and the minimum temperature. The freezing point of diesel oil refers to the oil under the conditions of cooling to the loss of liquidity when the maximum temperature. Diesel oil in the n-alkane content and high boiling point, the freezing point is also high. Diesel oil is generally used in the freezing point lower than the ambient temperature 3 ℃ ~ 5 ℃, therefore, with the seasonal and regional changes, the need to use different brands, that is, different points of commodity diesel fuel. In actual use, the diesel will precipitate crystals at low temperatures, the crystal grows to a certain extent will plug the filter, when the temperature is called cold filter point. Compared with the freezing point, it better reflects the actual use of performance. The same oil, the general freezing point than the freezing point of high 1 ℃ ~ 3 ℃. Using dewaxing method, can reduce the pour point, get low condensate diesel.Ignition(Ignitability):High-speed diesel engine requires diesel fuel injected into the combustion chamber and air quickly after the formation of a uniform mixture, and immediately automatically fire combustion, requiring fuel easy to spontaneous combustion. The time interval between the start of the injection of fuel into the cylinder and the initiation of ignition is called the ignition delay or ignition lag. The spontaneous ignition point of the fuel (temperature in the presence of air can automatically fire) is low, the ignition delay is short, that is, good fire performance.Copper corrosionAccording to GB / T 5096 methodMeasuredMethod summary: a piece of polished copper immersed in a certain amount of sample, according to product standards required to heat up to the specified temperature, to maintain a certain time. At the end of the test period, remove the copper plate, after washing and corrosion standard color plate to compare to determine the corrosion level.MoistureAccording to GB / T 260 method for determinationMethod Summary: a certain amount of sample mixed with 100mL anhydrous solvent distillation for less than 1 hour, according to the receiver to collect the water volume calculated sample moisture.Mechanical impuritiesAccording to GB / T 511 method for determinationMethod Summary: A certain amount of sample dissolved in the appropriate amount of warm solvent oil, has been constant weight of the filter filter, weighing is left on the filter impurities to obtain the mechanical impurities in the sample content.