Abstract:
A system and a method for calculating the cetane number, pour point, cloud point and aniline point of gas oil fractions of a crude oil sample from the density and gas chromatographic simulated distribution of the sample.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/445,183 filed Feb. 22, 2011, the disclosure of which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a method and process for the evaluation of samples of crude oil and its fractions by simulated distillation (SD), avoiding the need to conduct fractionation/distillation assays. 
       BACKGROUND OF THE INVENTION 
       [0003]    Crude oil originates from the decomposition and transformation of aquatic, mainly marine, living organisms and/or land plants that became buried under successive layers of mud and silt some 15-500 million years ago. They are essentially very complex mixtures of many thousands of different hydrocarbons. Depending on the source, the oil predominantly contains various proportions of straight and branched-chain paraffins, cycloparaffins, and naphthenic, aromatic, and polynuclear aromatic hydrocarbons. These hydrocarbons can be gaseous, liquid, or solid under normal conditions of temperature and pressure, depending on the number and arrangement of carbon atoms in the molecules. 
         [0004]    Crude oils vary widely in their physical and chemical properties from one geographical region to another and from field to field. Crude oils are usually classified into three groups according to the nature of the hydrocarbons they contain: paraffinic, naphthenic, asphaltic, and their mixtures. The differences are due to the different proportions of the various molecular types and sizes. One crude oil can contain mostly paraffins, another mostly naphthenes. Whether paraffinic or naphthenic, one can contain a large quantity of lighter hydrocarbons and be mobile or contain dissolved gases; another can consist mainly of heavier hydrocarbons and be highly viscous, with little or no dissolved gas. Crude oils can also include heteroatoms containing sulfur, nitrogen, nickel, vanadium and others elements in quantities that impact the refinery processing of the crude oil fractions. Light crude oils or condensates can contain sulfur in concentrations as low as 0.01 W % of sulfur; in contrast, heavy crude oils can contain as much as 5-6 W %. Similarly, the nitrogen content of crude oils can range from 0.001-1.0 W %. 
         [0005]    The nature of the crude oil governs, to a certain extent, the nature of the products that can be manufactured from it and their suitability for special applications. A naphthenic crude oil will be more suitable for the production of asphaltic bitumen, a paraffinic crude oil for wax. A naphthenic crude oil, and even more so an aromatic one, will yield lubricating oils with viscosities that are sensitive to temperature. However, with modern refining methods there is greater flexibility in the use of various crude oils to produce many desired type of products. 
         [0006]    A crude oil assay is a traditional method of determining the nature of crude oils for benchmarking purposes. Crude oils are subjected to true boiling point (TBP) distillations and fractionations to provide different boiling point fractions. The crude oil distillations are carried out using the American Standard Testing Association (ASTM) Method D 2892. The common fractions and their nominal boiling points are given in Table 1. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Fraction 
                 Boiling Point, ° C. 
               
               
                   
                   
               
             
             
               
                   
                 Methane 
                 −161.5  
               
               
                   
                 Ethane 
                 −88.6 
               
               
                   
                 Propane 
                 −42.1 
               
               
                   
                 Butanes 
                  −6.0 
               
               
                   
                 Light Naphtha 
                 36-90 
               
               
                   
                 Mid Naphtha 
                  90-160 
               
               
                   
                 Heavy Naphtha 
                 160-205 
               
               
                   
                 Light gas Oil 
                 205-260 
               
               
                   
                 Mid Gas Oil 
                 260-315 
               
               
                   
                 Heavy gas Oil 
                 315-370 
               
               
                   
                 Light Vacuum Gas Oil 
                 370-430 
               
               
                   
                 Mid Vacuum Gas Oil 
                 430-480 
               
               
                   
                 Heavy vacuum gas oil 
                 480-565 
               
               
                   
                 Vacuum Residue 
                 565+  
               
               
                   
                   
               
             
          
         
       
     
         [0007]    The yields, composition, physical and indicative properties of these crude oil fractions, where applicable, are then determined during the crude assay work-up calculations. Typical compositional and property information obtained from a crude oil assay is given in Table 2. 
         [0000]    
       
         
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Property 
                 Unit 
                 Property Type 
                 Fraction 
               
               
                   
               
             
             
               
                 Yield Weight and Volume % 
                 W % 
                 Yield 
                 All 
               
               
                 API Gravity 
                 ° 
                 Physical 
                 All 
               
               
                 Viscosity Kinematic @ 38° C. 
                 ° 
                 Physical 
                 Fraction boiling &gt;250° C. 
               
               
                 Refractive Index @ 20° C. 
                 Unitless 
                 Physical 
                 Fraction boiling &lt;400° C. 
               
               
                 Sulfur 
                 W % 
                 Composition 
                 All 
               
               
                 Mercaptan Sulfur, W % 
                 W % 
                 Composition 
                 Fraction boiling &lt;250° C. 
               
               
                 Nickel 
                 ppmw 
                 Composition 
                 Fraction boiling &gt;400° C. 
               
               
                 Nitrogen 
                 ppmw 
                 Composition 
                 All 
               
               
                 Flash Point, COC 
                 ° C. 
                 Indicative 
                 All 
               
               
                 Cloud Point 
                 ° C. 
                 Indicative 
                 Fraction boiling &gt;250° C. 
               
               
                 Pour Point, (Upper) 
                 ° C. 
                 Indicative 
                 Fraction boiling &gt;250° C. 
               
               
                 Freezing Point 
                 ° C. 
                 Indicative 
                 Fraction boiling &gt;250° C. 
               
               
                 Microcarbon Residue 
                 W % 
                 Indicative 
                 Fraction boiling &gt;300° C. 
               
               
                 Smoke Point, mm 
                 mm 
                 Indicative 
                 Fraction boiling between 
               
               
                   
                   
                   
                 150-250 
               
               
                 Cetane Index 
                 Unitless 
                 Indicative 
                 Fraction boiling between 
               
               
                   
                   
                   
                 150-400 
               
               
                 Aniline Point 
                 ° C. 
                 Indicative 
                 Fraction boiling &lt;520° C. 
               
               
                   
               
             
          
         
       
     
         [0008]    Due to the number of distillation cuts and the number of analyses involved, the crude oil assay work-up is both costly and time consuming. 
         [0009]    In a typical refinery, crude oil is first fractionated in the atmospheric distillation column to separate sour gas and light hydrocarbons, including methane, ethane, propane, butanes and hydrogen sulfide, naphtha (36°-180° C.), kerosene (180°-240° C.), gas oil (240°-370° C.) and atmospheric residue (&gt;370° C.). The atmospheric residue from the atmospheric distillation column is either used as fuel oil or sent to a vacuum distillation unit, depending on the configuration of the refinery. The principal products obtained from vacuum distillation are vacuum gas oil, comprising hydrocarbons boiling in the range 370°-520° C., and vacuum residue, comprising hydrocarbons boiling above 520° C. The crude assay data help refiners to understand the general composition of the crude oil fractions and properties so that the fractions can be processed most efficiently and effectively in an appropriate refining unit. Indicative properties are used to determine the engine/fuel performance or usability or flow characteristic or composition. A summary of the indicative properties and determination methods with description are given below. 
         [0010]    The cetane number of diesel fuel oil, determined by the ASTM D613 method, provides a measure of the ignition quality of diesel fuel; as determined in a standard single cylinder test engine; which measures ignition delay compared to primary reference fuels. The higher the cetane number; the easier the high-speed; direct-injection engine will start; and the less white smoking and diesel knock after start-up are. The cetane number of a diesel fuel oil is determined by comparing its combustion characteristics in a test engine with those for blends of reference fuels of known cetane number under standard operating conditions. This is accomplished using the bracketing hand wheel procedure which varies the compression ratio (hand wheel reading) for the sample and each of the two bracketing reference fuels to obtain a specific ignition delay, thus permitting interpolation of cetane number in terms of hand wheel reading. 
         [0011]    The cloud point, determined by the ASTM D2500 method, is the temperature at which a cloud of wax crystals appears when a lubricant or distillate fuel is cooled under standard conditions. Cloud point indicates the tendency of the material to plug filters or small orifices under cold weather conditions. The specimen is cooled at a specified rate and examined periodically. The temperature at which cloud is first observed at the bottom of the test jar is recorded as the cloud point. This test method covers only petroleum products and biodiesel fuels that are transparent in 40 mm thick layers, and with a cloud point below 49° C. 
         [0012]    The pour point of petroleum products, determined by the ASTM D97 method, is an indicator of the ability of oil or distillate fuel to flow at cold operating temperatures. It is the lowest temperature at which the fluid will flow when cooled under prescribed conditions. After preliminary heating, the sample is cooled at a specified rate and examined at intervals of 3° C. for flow characteristics. The lowest temperature at which movement of the specimen is observed is recorded as the pour point. 
         [0013]    The aniline point, determined by the ASTM D611 method, is the lowest temperature at which equal volumes of aniline and hydrocarbon fuel or lubricant base stock are completely miscible. A measure of the aromatic content of a hydrocarbon blend is used to predict the solvency of a base stock or the cetane number of a distillate fuel Specified volumes of aniline and sample, or aniline and sample plus n-heptane, are placed in a tube and mixed mechanically. The mixture is heated at a controlled rate until the two phases become miscible. The mixture is then cooled at a controlled rate and the temperature at which two phases separate is recorded as the aniline point or mixed aniline point. 
         [0014]    To determine these properties of gas oil or naphtha fractions conventionally, these fractions have to be distilled off from the crude oil and then measured/determined using various analytical methods that are laborious, costly and time consuming. 
         [0015]    SD is a technique which separates individual hydrocarbon components in the order of their boiling points, and is used to simulate time-consuming laboratory-scale physical distillation procedures. The separation is usually accomplished with a gas chromatograph equipped with a chromatography column coated with a nonpolar (hydrocarbon-like) stationary phase, an oven and injector which can be temperature programmed with. A flame ionization detector (FID) is used for detection and measurement of the hydrocarbon analytes. The SD analysis result provides a quantitative percent mass yield as a function of boiling point of the hydrocarbon components of the sample being analyzed. The chromatographic elution times of the hydrocarbon components are calibrated to the atmospheric equivalent boiling point (AEBP) of the individual n-alkane as described in a method from the ASTM by using n-alkane (n-paraffin) reference material. In the SD method ASTM D2887, the n-alkane calibration reference covers the boiling range 55-538° C. (100-1000° F.) which covers the n-alkanes with a chain length of about C5-C44. 
         [0016]    Alternative methods may be used, including ASTM D5236, ASTM D86, ASTM D5399, ASTM D6352-04, ASTM D7213-05e1, ASTM D7398-07, ASTM D7169-05, ASTM D7096-10, ASTM D7500-10, ASTM D5307-97, ASTM D1160, ASTM D2892, or any other methods based upon gas chromatography, true boiling point distillation, supercritical fluid chromatography, and equilibrium flash. There are well-known correlations to convert distillation numbers: for example, if the true boiling point distillation (ASTM D2892) is known, the SD data (ASTM D2892) can be estimated. While there are not yet ASTM methods using supercritical fluid chromatography, non-standardized lab methods are known. 
         [0017]    In the high temperature simulated distillation method (HTSD), the n-alkane calibration reference (a hydrogenated polyolefin wax, polywax 655) covers the boiling range 36-750° C. (97-1382° F.) which covers the n-alkanes with a chain length of about C5-C120. A key difference between ASTM D2887 and HTSD is the ability of HTSD to handle residue-containing samples (i.e. material boiling &gt;538° C. or 1000° F.). SD and laboratory-scale physical distillation methods are routinely used for determining boiling ranges of petroleum crude oils and refined products. The boiling points with yield profile data of these materials are used by refinery engineers to make operational decisions to improve product yields and product quality. SD is valuable for, and can improve results from, computer modeling of refining processes for improvements in design and process optimization. Precise yield correlations between HTSD and crude assay distillation (a procedure which uses methods ASTM D2892 and D5236) have allowed HTSD to be successfully used in place of the physical distillation procedures. A typical simulated distillation chart obtained from a gas chromatogram of crude oil is shown in  FIG. 1 , where the W % of distilled fractions is plotted against the boiling temperature. 
         [0018]    Any new rapid, direct method to help better understand the crude oil composition and properties from the analysis of whole crude oil will save producers, marketers, refiners and/or other crude oil users substantial expense, effort and time. Therefore, a need exists for an improved system and method for determining the properties of crude fractions from different sources and classifying the crude oil fractions based on their boiling point characteristics and/or properties. 
       SUMMARY OF THE INVENTION 
       [0019]    The above objects and further advantages are provided by the present invention which broadly comprehends a system and a method for determining the indicative properties of a hydrocarbon sample. In accordance with the invention, indicative properties (i.e., cetane number, pour point, cloud point and aniline point) of gas oil fraction in crude oils are predicted by density and simulated distillation of crude oils. The correlations also provide information about the gas oil properties without fractionation/distillation (crude oil assays) and will help producers, refiners, and marketers to benchmark the oil quality and, as a result, valuate the oils without performing the customary extensive and time-consuming crude oil assays. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Further advantages and features of the present invention will become apparent from the following detailed description of the invention when considered with reference to the accompanying drawing which is a graphic plot of simulated distillation data obtained from gas chromatography for three types of crude oil. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0021]    Crude oils&#39; simulated distillation were obtained by gas chromatography according to the ASTM Method 5236 and/or its derivation for high temperature. 
         [0022]    The indicative properties (i.e., the cetane number, pour point, cloud point and aniline point) of the gas oil fraction boiling in the range 180-370° C. can be predicted from the density (at 15° C./4° C.) and the mid boiling point of the gas oil or whole crude oil (T MBP ), measured in Kelvin. That is, 
         [0000]      Indicative Property− f (density(15/4) crude oil   ,T   MBP ( K ) gas oil )  (1a);
 
         [0000]      Indicative Property= f (density(15/4) crude oil   ,T   MBP ( K ) crude oil )  (1b);
 
         [0023]    Equations (2) through (5) show, respectively, the cetane number, pour point, cloud point and aniline point that can be predicted from the density and simulated distillation of crude oils. 
         [0000]      Cetane Number (CET)= K   CET   +X 1 CET *DEN+X2 CET *DEN 2   +X 3 CET *DEN 3 +X4 CET *( T   MSP /1000)+ X 5 CET *( T   MBP /1000)+ X 6 CET *( T   MBP /1000) 3 +X7 CET *DEN*( T   MBP /1000)  (2);
 
         [0000]      Pour Point (PP)= K   PP   X 1 PP *DEN+X2 PP *DEN 2   +X 3 PP *DEN 3 +X4 PP *( T   MBP /1000)+ X 5 PP ( T   MBP /1000) 2   +X 6 PP *( T   MBP /1000) 3 +X7 PP *DEN*( T   MBP /1000)  (3);
 
         [0000]      Cloud Point (CP)= K   CP   +X 1 CP *DEN+X2 CP *DEN 2   +X 3 CP *DEN 3 +X4 CP *( T   MBP /1000)+ X 5 CP *( T   MBP /1000) 2   X 6 CP *( T   MBP /1000) 3 +X7 CP *DEN*( T   MBP /1000)  (4);
 
         [0000]      Aniline Point (AP)= K   AP   +X 1 AP *DEN+X2 AP *DEN 2   +X 3 AP *DEN 3 +X4 AP *( T   MBP /1000)+ X 5 AP *( T   MBP /1000) 2   +X 6 AP *( T   MBP /1000) 3 +X7 AP *DEN*( T   MBP /1000)  (5);
 
         [0024]    where: 
         [0025]    DEN=density of the crude oil sample; 
         [0026]    T MBP =mid boiling point of the gas oil or crude oil (derived from the simulated distillation curves of crude oils); 
         [0000]    and K CET , X1 CET -X7 CET , K PP , X1 PP -X7 PP , K CP , X1 CP -X7 CP , K AP , and X1 AP -X7 AP  are constants that were developed using linear regression techniques, and which are given in Table 3. 
         [0000]    
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Cetane 
                   
                   
                   
               
               
                   
                 Number 
                 Pour Point 
                 Cloud Point 
                 Aniline Point 
               
               
                 Property 
                 (CET) 
                 (PP) 
                 (CP) 
                 (AP) 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 K 
                 544509.8 
                 1344488.4 
                 395024.0 
                 24390.7 
               
               
                 X1 
                 −1932359.8 
                 −4907366.2 
                 −1429569.6 
                 −49357.1 
               
               
                 X2 
                 2161099.3 
                 5503008.0 
                 1604628.0 
                 52455.3 
               
               
                 X3 
                 −796440.7 
                 −2031119.7 
                 −592968.1 
                 −18616.3 
               
               
                 X4 
                 142762.7 
                 527938.4 
                 136360.5 
                 −41985.4 
               
               
                 X5 
                 −177339.2 
                 −699945.0 
                 −177392.5 
                 65171.0 
               
               
                 X6 
                 90209.8 
                 361176.8 
                 91570.3 
                 −33881.4 
               
               
                 X7 
                 −30458.6 
                 −87436.2 
                 −25137.2 
                 408.8 
               
               
                   
               
             
          
         
       
     
         [0027]    Note that as an alternative to determining the mid boiling point of the oil stream at the 50 W % point of the simulated distillation data, it may be calculated by taking the average of boiling points. Alternatively, it may be calculated as a weighted average boiling point (WABP), as shown in equation (6), below. 
         [0000]    
       
         
           
             
               
                 
                   
                     W 
                      
                     
                         
                     
                      
                     A 
                      
                     
                         
                     
                      
                     B 
                      
                     
                         
                     
                      
                     P 
                   
                   = 
                   
                     
                       
                         
                           ( 
                           
                             
                               T 
                               10 
                             
                             * 
                             10 
                           
                           ) 
                         
                         + 
                         
                           ( 
                           
                             
                               T 
                               30 
                             
                             * 
                             30 
                           
                           ) 
                         
                         + 
                         
                           ( 
                           
                             
                               T 
                               50 
                             
                             * 
                             50 
                           
                           ) 
                         
                         + 
                         
                           ( 
                           
                             
                               T 
                               70 
                             
                             * 
                             70 
                           
                           ) 
                         
                         + 
                         
                           
                             T 
                             90 
                           
                           * 
                           90 
                         
                       
                       ) 
                     
                     
                       10 
                       + 
                       30 
                       + 
                       50 
                       + 
                       70 
                       + 
                       90 
                     
                   
                 
               
               
                 
                   ( 
                   6 
                   ) 
                 
               
             
           
         
       
     
         [0028]    where T 10  is the boiling temperature of oil determined when 10 W % or V % of the fraction is recovered during the distillation, and where T 30 , T 50 , T 70  and T 90  are determined accordingly. An example calculation of WABP is presented below. When the sample is distilled, the boiling point of the sample is determined to be 149° C. when 10 W % of the sample is recovered. Thus, T 10  is 149° C., and the other figures are determined similarly: 
         [0000]    
       
         
               
               
             
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 W % Recovered 
               
             
          
           
               
                   
                 10 
                 30 
                 50 
                 70 
                 90 
               
               
                   
                   
               
             
          
           
               
                   
                 Boiling 
                 149 
                 230 
                 282 
                 325 
                 371 
               
               
                   
                 Temperature, 
               
               
                   
                 ° C. 
               
               
                   
                   
               
             
          
         
       
     
         [0000]    
       
         
           
             
               W 
                
               
                   
               
                
               A 
                
               
                   
               
                
               B 
                
               
                   
               
                
               T 
             
             = 
             
               
                 [ 
                 
                   
                     149 
                     * 
                     10 
                   
                   + 
                   
                     230 
                     * 
                     30 
                   
                   + 
                   
                     282 
                     * 
                     50 
                   
                   + 
                   
                     325 
                     * 
                     70 
                   
                   + 
                   
                     371 
                     * 
                     90 
                   
                 
                 ] 
               
               / 
               
                   
                 
                   
                     [ 
                     
                       10 
                       + 
                       30 
                       + 
                       50 
                       + 
                       70 
                       + 
                       90 
                     
                     ] 
                   
                   = 
                   315 
                 
               
             
           
         
       
     
         [0029]    The following example is provided to demonstrate an application of equations (2) through (5). A sample of Arabian medium crude with a 15° C./4° C. density of 0.8828 Kg/I was analyzed by gas chromatography using the ASTM D2887 method. The simulated distillation data is shown in Table 4: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 W % 
                 Temp. ° C. 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 0 
                   
               
               
                   
                 1 
               
               
                   
                 2 
                 37 
               
               
                   
                 3 
                 68 
               
               
                   
                 4 
                 83 
               
               
                   
                 5 
                 94 
               
               
                   
                 6 
                 100 
               
               
                   
                 7 
                 113 
               
               
                   
                 8 
                 121 
               
               
                   
                 9 
                 127 
               
               
                   
                 10 
                 138 
               
               
                   
                 11 
                 144 
               
               
                   
                 12 
                 151 
               
               
                   
                 13 
                 157 
               
               
                   
                 14 
                 165 
               
               
                   
                 15 
                 172 
               
               
                   
                 16 
                 175 
               
               
                   
                 17 
                 185 
               
               
                   
                 18 
                 191 
               
               
                   
                 19 
                 196 
               
               
                   
                 20 
                 204 
               
               
                   
                 21 
                 210 
               
               
                   
                 22 
                 216 
               
               
                   
                 23 
                 222 
               
               
                   
                 24 
                 229 
               
               
                   
                 25 
                 235 
               
               
                   
                 26 
                 241 
               
               
                   
                 27 
                 249 
               
               
                   
                 28 
                 255 
               
               
                   
                 29 
                 261 
               
               
                   
                 30 
                 267 
               
               
                   
                 31 
                 272 
               
               
                   
                 32 
                 279 
               
               
                   
                 33 
                 285 
               
               
                   
                 34 
                 290 
               
               
                   
                 35 
                 297 
               
               
                   
                 36 
                 303 
               
               
                   
                 37 
                 308 
               
               
                   
                 38 
                 315 
               
               
                   
                 39 
                 319 
               
               
                   
                 40 
                 326 
               
               
                   
                 41 
                 331 
               
               
                   
                 42 
                 337 
               
               
                   
                 43 
                 342 
               
               
                   
                 44 
                 348 
               
               
                   
                 45 
                 354 
               
               
                   
                 46 
                 360 
               
               
                   
                 47 
                 366 
               
               
                   
                 48 
                 372 
               
               
                   
                 49 
                 378 
               
               
                   
                 50 
                 384 
               
               
                   
                 51 
                 390 
               
               
                   
                 52 
                 396 
               
               
                   
                 53 
                 402 
               
               
                   
                 54 
                 409 
               
               
                   
                 55 
                 415 
               
               
                   
                 56 
                 422 
               
               
                   
                 57 
                 428 
               
               
                   
                 58 
                 434 
               
               
                   
                 59 
                 440 
               
               
                   
                 60 
                 446 
               
               
                   
                 61 
                 452 
               
               
                   
                 62 
                 458 
               
               
                   
                 63 
                 465 
               
               
                   
                 64 
                 471 
               
               
                   
                 65 
                 478 
               
               
                   
                 66 
                 485 
               
               
                   
                 67 
                 492 
               
               
                   
                 68 
                 499 
               
               
                   
                 69 
                 506 
               
               
                   
                 70 
                 513 
               
               
                   
                 71 
                 520 
               
               
                   
                 72 
                 528 
               
               
                   
                 73 
                 535 
               
               
                   
                 74 
                 543 
               
               
                   
                 75 
                 551 
               
               
                   
                 76 
                 559 
               
               
                   
                 77 
                 567 
               
               
                   
                 78 
                 575 
               
               
                   
                 79 
                 583 
               
               
                   
                 80 
                 592 
               
               
                   
                 81 
                 599 
               
               
                   
                 82 
                 608 
               
               
                   
                   
               
             
          
         
       
     
         [0030]    The mid boiling point of the crude oil is taken from the data at the 50 W % point, which is 384° C. (657 K). 
         [0031]    Applying equation 2 and the constants from Table 3, 
         [0000]    
       
         
           
             
               Cetane 
                
               
                   
               
                
               Number 
                
               
                   
               
                
               
                 ( 
                 CET 
                 ) 
               
             
             = 
             
               
                 
                   K 
                   CET 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     1 
                     CET 
                   
                   * 
                   DEN 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     2 
                     CET 
                   
                   * 
                   
                     DEN 
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     3 
                     CET 
                   
                   * 
                   
                     DEN 
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     4 
                     CET 
                   
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     5 
                     CET 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     6 
                     CET 
                   
                   * 
                   
                     
                       T 
                        
                       
                         ( 
                         
                           
                             T 
                             MBP 
                           
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                     
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     7 
                     CET 
                   
                   * 
                   DEN 
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
               
               = 
               
                 
                   
                     ( 
                     544509.8 
                      
                     
                         
                     
                     ) 
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         1932359.8 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       2161099.3 
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         796440.7 
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       142762.7 
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         177339.2 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       90209.8 
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         30458.6 
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                 
                 = 
                 59 
               
             
           
         
       
     
         [0032]    Applying equation 3 and the constants from Table 3, 
         [0000]    
       
         
           
             
               Pour 
                
               
                   
               
                
               Point 
                
               
                   
               
                
               
                 ( 
                 PP 
                 ) 
               
             
             = 
             
               
                 
                   K 
                   PP 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     1 
                     PP 
                   
                   * 
                   DEN 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     2 
                     PP 
                   
                   * 
                   
                     DEN 
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     3 
                     PP 
                   
                   * 
                   
                     DEN 
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     4 
                     PP 
                   
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     5 
                     PP 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     6 
                     PP 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     7 
                     PP 
                   
                   * 
                   DEN 
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
               
               = 
               
                 
                   
                     ( 
                     1344488.4 
                      
                     
                         
                     
                     ) 
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         4907366.2 
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       5503008.06 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         2031119.7 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       527938.4 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         699945.0 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       361176.8 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         87436.2 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                 
                 = 
                 
                   - 
                   10 
                 
               
             
           
         
       
     
         [0000]    Applying equation 4 and the constants from Table 3, 
         [0000]    
       
         
           
             
               Cloud 
                
               
                   
               
                
               Point 
                
               
                   
               
                
               
                 ( 
                 CP 
                 ) 
               
             
             = 
             
               
                 
                   K 
                   CP 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     1 
                     CP 
                   
                   * 
                   DEN 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     2 
                     CP 
                   
                   * 
                   
                     DEN 
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     3 
                     CP 
                   
                   * 
                   
                     DEN 
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     4 
                     CP 
                   
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     5 
                     CP 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     6 
                     CP 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     7 
                     CP 
                   
                   * 
                   DEN 
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
               
               = 
               
                 
                   
                     ( 
                     39502.0 
                      
                     
                         
                     
                     ) 
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         1429569.6 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       1604628.0 
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         592968.1 
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                          
                         
                             
                         
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       136360.5 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         177392.5 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       90209.8 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         30458.6 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                 
                 = 
                 59 
               
             
           
         
       
     
         [0000]    Applying equation 5 and the constants from Table 3, 
         [0000]    
       
         
           
             
               Pour 
                
               
                   
               
                
               Point 
                
               
                   
               
                
               
                 ( 
                 PP 
                 ) 
               
             
             = 
             
               
                 
                   K 
                   PP 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     1 
                     PP 
                   
                   * 
                   DEN 
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     2 
                     PP 
                   
                   * 
                   
                     DEN 
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     3 
                     PP 
                   
                   * 
                   
                     DEN 
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     4 
                     PP 
                   
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     5 
                     PP 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     2 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     6 
                     PP 
                   
                   * 
                   
                     
                       ( 
                       
                         
                           T 
                           MBP 
                         
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                     3 
                   
                 
                 + 
                 
                   X 
                    
                   
                       
                   
                    
                   
                     7 
                     PP 
                   
                   * 
                   DEN 
                   * 
                   
                     ( 
                     
                       
                         T 
                         MBP 
                       
                        
                       
                         / 
                       
                        
                       1000 
                     
                     ) 
                   
                 
               
               = 
               
                 
                   
                     ( 
                     1344488.4 
                      
                     
                         
                     
                     ) 
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         4907366.2 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       5503008.06 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         2031119.7 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         0.8828 
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       527908.4 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         699945.0 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       2 
                     
                   
                   + 
                   
                     
                       ( 
                       361176.8 
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       
                         ( 
                         
                           657 
                            
                           
                             / 
                           
                            
                           1000 
                         
                         ) 
                       
                       3 
                     
                   
                   + 
                   
                     
                       ( 
                       
                         - 
                         87436.2 
                       
                        
                       
                           
                       
                       ) 
                     
                      
                     
                       ( 
                       0.8828 
                       ) 
                     
                      
                     
                       ( 
                       
                         657 
                          
                         
                           / 
                         
                          
                         1000 
                       
                       ) 
                     
                   
                 
                 = 
                 
                   - 
                   10 
                 
               
             
           
         
       
     
         [0033]    The method is applicable for naturally occurring hydrocarbons derived from crude oils, bitumens, heavy oils, shale oils and from refinery process units including hydrotreating, hydroprocessing, fluid catalytic cracking, coking, and visbreaking or coal liquefaction. 
         [0034]    The system and method of the present invention have been described above and with reference to the attached figure; however, modifications will be apparent to those of ordinary skill in the art and the scope of protection for the invention is to be defined by the claims that follow.