The cetane index was calculated by astm d4737 and astm d976 and the derived cetane number dcn was measured using an ignition quality tester iqt. Astm d976 06 standard test method for calculated cetane. It plays a similar role for diesel as octane rating does for gasoline. Test method d4737 procedure a may be less applicable to no. Cetane is the chemical compound with chemical formula nc 16 h 34, today named hexadecane according to iupac rules. In a particular diesel engine, higher cetane fuels will have shorter ignition delay periods than lower cetane fuels. Cetane numbers are only used for the relatively light distillate diesel oils. Pdf neural network prediction of cetane number and. Astm d6890 is an approved alternative test method to d6 in us diesel spec astm d975. It is a supplementary tool for predicting cetane number when used with due regard for its limitations. In cases of dispute, test method d6 shall be the referee test method. This interest covers both petroleumbased and syntheticbased, as well as blends thereof in order to i mprove the confidence in using dcn as a replacement test for cn.
Standard test method for cetane number of diesel fuel oil. This equation employs the same formulation as d97680 but differs from it, in that its middistillation. This is an estimation of measured cetane number based on formulas in astm d976 or astm d4737. Astmd976 standard test method for calculated cetane. Astm d976062016 standard test method for calculated. Astm d976 d4737 cetane index as a supplementary tool, the calculated cetane index by four variable equation must be used with due regard for its limitations. Adjunct to d976 test methods for calculated cetane index of. The equation for calculated cetane index in test method d976 80 and in this version d976 06 of the test method are the same. Note 1 this test method is temporarily retained because the proposal to the u. Astm d d pdf director august 31, 2019 admin personal growth leave a comment on astm d976 pdf. It is an inverse of the similar octane rating for gasoline petrol. Cetane number cetane rating is an indicator of the combustion speed of diesel fuel and compression needed for ignition. Astm d976 d4737 cetane index this method for estimating cetane number was developed by chevron research co. Prediction of physical properties and cetane number of.
The characterisation and cetane number determination of synthetic. Astm d976 04be1 standard test methods for calculated. It is an unbranched alkane, a saturated hydrocarbon chain with no cycles. Neural network prediction of cetane number and density of diesel fuel from its chemical composition determined by lc and gcms article pdf. Astm has recently released a new revision to standard test method for cetane number of diesel fuel oil, d617b, which incorporates changes that affects use of current diesel products by engine users. Astm d976062011 standard test method for calculated. Astm d976 pdf designation d 06 standard test method for calculated cetane index of free astm cetane number of distillate fuels from api gravity and. The calculations rely on diesel fuels t10, t50, t90 distillation points, and gravitydensity to estimate the cetane number. Research engine method astm d6 cetane number 2 and 4variable methods astm d976 and d4737 cetane index iqt method astm d6890 derived cetane number. An equation was developed relating the cetane number and.
Limitations of the use of cetane index for alternative. It is a supplementary tool asgm estimate cetane number when used with due regard for its limitations. The sample population used to regress the formulas for d976 and d4737 are different, and the accuracy r, r is different. Referenced documents purchase separately the documents listed below are referenced within the subject standard but are not provided as part of the standard. Cetane index ci an approximation of cetane number based on an empirical relationship with density and volatility parameters.
It is clear that this method is quite inaccurate for predicting cetane numbers. The cn is an important factor in determining the quality of diesel fuel, but not the only one. Riazi10 was used to estimate the molecular weights of the diesel fuels. Cetane number cn a prime indicator of diesel fuel quality, is a quantity indicating the combustion behaviour of diesel fuel and compression required for ignition in diesel engines. Generally, it has been found that use of test method d4737 results in less offset than use of test method d976, but there can be specific cases where this is not true. Astm d976 062011 standard test method for calculated. This method for estimating cetane number was developed by chevron research co.
All bsi british standards available online in electronic and print formats. Standard test method for calculated cetane index of distillate fuels. No other units of measurement are included in this standard. The index value, as computed from the formula, is termed the calculated cetane index. Pdf evaluation of available correlations for prediction of diesel. Figure 2 shows the correlation between the measured cetane numbers and the cetane index as predicted using astm d976. Astm d976 062016 standard test method for calculated cetane. In cases where the cetane number of a fuel has been initially established, the index is useful as a cetane number check on subsequent samples of that fuel, provided its source and mode of manufacture remain unchanged. Product update for immediate release, july 2007 iqt. Cetane number or cn is an indicator of the combustion speed of diesel fuel. Since using dedicated engines and processes or instruments for real fuel tests is painstaking, expensive, and timeconsuming, many diesel fuel formulators use a calculated method to determine cetane numbers. Cetane number or cn is a measure of a fuels ignition delay.
Variations of cetane number of jatropha biodiesel blends. Two common tests are astm d976 and astm 4737 that use fuel density and boilingevaporation points to arrive at cetane ratings. Test method d is the preferred method as estimator of cetane. D976062016 standard test method for calculated cetane index of distillate fuels cetane. The calculated cetane index is not an optional method for expressing astm cetane number. Fast evaluation of cn supports efficient utilisation of the valuable cetane rich feedstock and helps to minimise giveaway.
Purchase your copy of astm d976 062016 as a pdf download or hard copy directly from the official bsi shop. Astm d7668 17 standard test method for determination of. Army needs to understand how well the astm d6890 derived cetane number dcn test correlates to astm d6 cetane number cn test for a variety of fuels. Both of these processes derive cetane numbers by measuring not only the fuel density, but also its boiling and evaporation levels. Figure 3 shows no 120 140 150 160 170 180 190 temperature figure i cetane number versus reaction temperatures at different space velocities. Its determination is usually arduous and expensive. Astm d976 062016 standard test method for calculated.
It is a supplementary tool to estimate cetane number when used with due regard for its limitations. Cetane number is an important parameter in evaluating the quality of biodiesel fuel. Method of compositional analysis of diesel fuels high performance liquid chromatographic. Cetane ignites very easily under compression, so it was assigned a cetane number of 100, while alphamethyl naphthalene was assigned a cetane number of 0. Test method d is the preferred method as estimator of cetane number. This study examines the determination of cn of jatropha biodiesel blends with mineral diesel using their physical properties, and their variations of cn with. Astm d976 062016 standard test method for calculated cetane index of distillate fuels. The present study is aimed at developing the mathematical relationship between viscosity, density, calorific value, flash point and cetane number cn. What effect does the cetane number have on engine performance. One such test that is most commonly used is known as the astm d976. Cetane number determination of synthetic diesel fuels. It may be employed for approximating cetane number where the quantity of sample is too small for an engine rating.
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