UOP 948-2007 RELATIVE DENSITY OF GAS MIXTURES BY CALCULATION FROM COMPOSITION.pdf

1、 IT IS THE USERS RESPONSIBILITY TO ESTABLISH APPROPRIATE PRECAUTIONARY PRACTICES AND TO DETERMINE THE APPLICABILITY OF REGULATORY LIMITATIONS PRIOR TO USE. EFFECTIVE HEALTH AND SAFETY PRACTICES ARE TO BE FOLLOWED WHEN UTILIZING THIS PROCEDURE. FAILURE TO UTILIZE THIS PROCEDURE IN THE MANNER PRESCRIB

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4、2.9585 PHONE. Relative Density of Gas Mixtures by Calculation from Composition UOP Method 948-07 Scope This method is for calculating the relative density of gas mixtures, generated by typical refinery processes, from their composition as determined by UOP Method 539 or any other suitable method. Th

5、is method can be used in place of UOP Method 114. The relative density of air is defined as unity (1.00). References UOP Method 114, “Relative Density of Gas by Schilling Effusion Method,” www.astm.org UOP Method 539, “Refinery Gas Analysis by Gas Chromatography,” www.astm.org Outline of Method The

6、sample composition, in mol-%, is determined by UOP Method 539 or other suitable method. The relative density of the sample is then calculated using a commercially available software program. A manual calculation that yields an approximate relative density value is also included in this method. The s

7、oftware program provides the more accurate value because it takes into account deviations from the Ideal Gas Law. Apparatus References to catalog numbers and suppliers are included as a convenience to the user. Other suppliers may be used. Computer, personal, capable of supporting the software appli

8、cation Software, ProSim Simulus Thermodynamics, Energis Corporation. Other software that performs the same function may be used. Procedure Obtain a gas analysis of the sample using UOP Method 539 or other suitable method. 2 of 3 948-07 Calculations Preferred Method of Calculation Install the softwar

9、e on the personal computer and enter the composition data into the program. The program will calculate the sample relative density. The program computes the relative density taking into account deviations from the Ideal Gas Law. Report the results to two decimal places. Optional Method of Calculatio

10、n If a relative density value is needed immediately, and the software is not available, a manual calculation that yields an approximate relative density value for the sample can be performed as follows. Using mol-% values for the components in the sample, calculate the sample relative density using

11、Equation 1: 964.28M100CRn1iii= (1) where: C = component concentration, mol-% M = molecular weight of component (from Table), g/mol R = calculated sample relative density 28.964 = molecular weight of air, g/mol 100 = factor to convert from % Table Molecular Weights of Refinery Gas Components Componen

12、t Molecular Weight, g/mol Component Molecular Weight, g/mol Hydrogen 2.016 Propylene 42.08 Argon* 39.95 Isobutane 58.12 Oxygen* 32.00 n-Butane 58.12 Nitrogen 28.01 1-Butene 56.12 Carbon Monoxide 28.01 Isobutylene 56.12 Carbon Dioxide 44.00 trans-2-Butene 56.12 Methane 16.04 cis-2-Butene 56.12 Ethane

13、 30.07 1,3-Butadiene 54.09 Ethylene 28.05 C5Paraffins 72.15 Propane 44.11 C5Olefins 70.14 * Oxygen and argon are not separated by UOP Method 539. Use values appropriate to the expected sample composition. Report the final sample relative density to one decimal place. The optional calculation procedu

14、re does not take into account deviations from the Ideal Gas Law, and is, therefore, less accurate than the preferred method. Precision The precision of this method is limited by the precision of UOP Method 539 or other method used to determine the composition of the sample. If component values can b

15、e reported to two decimal 3 of 3 948-07 places, then the relative density determined using the preferred method of calculation is also good to two decimal places. Accuracy The accuracy of this method is limited by the accuracy of the composition data input into the software program. The software pro

16、gram itself is capable of one percent (relative) accuracy when working with typical refinery gas mixtures at temperatures and pressures not near critical conditions. Accuracy of data generated on atypical gas mixtures cannot be guaranteed. The accuracy of the manual calculation is also impacted by t

17、he gas mixtures deviation from the Ideal Gas Law. Time for Analysis The elapsed time and labor requirement for the calculations specified in this method are the same, 0.1 hour for the preferred (ProSim software) method of calculating, and 0.3 hour for the optional (manual) method. See UOP Method 539 for its time requirements. Suggested Supplier Energis Corporation, 2566 SW Westfield St., Port St. Lucie, FL 34953 (772-873-4072)