1、P-6 2 II 3824699 0010975 370 Technical Publication TP-6 Experimentally Based Thermodynamic Properties of Propane V. L. Bhirud J. E. Powers The University of Michigan Ann Arbor, Michigan January, 1982 1812 First Place Tulsa, Okla. 74103 Phone: 918/582-5 112 GPA TP-6 82 EI 3824679 0010776 207 W FOREWO
2、RD One of the earliest major research projects initiated by GPA was to obtain experimental low temperature enthalpy data. of Michigan during the period 1962-1971. Cl, C2, and C3. During the later years of the project, when Professor John H. Powers was the chief investigator, some very accurate entha
3、lpy data were acquired. While only enthalpy data were obtained experimentally, the accuracy of these data were such that it was deemed worthwhile to derive other thermodynamic properties from the basic enthalpy data. Results of the nominal 95% Cl - 5% C3 system were published by Bhirud and Powers as
4、 “Thermodynamic Properties of 5 Mole Percent Propane in Methane Mixture.“ This is a similar report covering a nominal 100% C3 system by the same authors. This was at the University The systems studied contained chiefly Our thanks are extended to Professor Powers for his dedication in completin a len
5、gthy and repetitive type project. 1 C 1 Sutton, Secretary Gas Processors Association . TABLE OF CONTENTS LIST OF TABLESi. iii V 2 PREPARATION OF TABLES AND DIAGRAMS OF THE THERMODYNAMIC PROPERTIES OF PROPANE. 2 Procedures. 2 Results 5 A. Tables of Thermodynamic Values. 5 B. Representation in Graphic
6、al Form. 6 LITERATURE CITED 13 APPENDIX I. 40 A. Calorimetric Data. 40 1. Latent Heat of Vaporization. 40 2. Saturated Liquid Heat Capacity 40 3. Isobaric Heat Capacities 41 4. Isothermal Throttling Coefficients 41 5. Joule-Thomson Coefficients 42 B. Volumetric Data (Including Critical Constants). 4
7、2 A. Adjustment of the Boundaries of the Two-Phase Region 44 B. Smoothing in the Vicinity of the Critical Point. 44 C. Corrections Made in the Low Temperature (Liquid) Region. 51 . GPA TP-b 82 3824697 OOLD778 OT m APPENDIX III. INTERPRETATION OF DATA FROM THE LITERATURE ON THE VOLUMETRIC BEHAVIOR OF
8、 PROPANE APPENDIX IV . PRELIMINARY ESTIMATES OF ENTROPY A . Isobaric Differences in Entropy . B . Isothermal Differences in Entropy . C . Checks of the Thermodynamic Consistency for the Preliminary Estimates of Entropy APPENDIX V . ADJUSTMENT OF PRELIMINARY SMOOTHED VALUES OF ENTHALPY AND SPECIFIC V
9、OLUME TO OBTAIN THERMODYNAMIC CONSISTENCY OF H. 6 and u VALUES . A . Adjustment of Enthalpy Values B . Improved Estimates of Entropy Differences . C . Adjustment of Volumetric Values . D . Final Values of Entropy Differences . APPENDIX VI . PREPARATION OF TABLES AND DIAGRAMS OF THE THERMODYNAMIC PRO
10、PERTIES OF PROPANE . A . B . C . D . Bases 2 . Entropy Values (Absolute) Values Tabulated at Temperatures Corresponding to Isothermal Calorimetric Determinations . Diagrams of Thermodynamic Properties Tabulated Values of Enthalpy and Entropy 2 . Properties in the Single Phase Region . 1 . Enthalpy V
11、alues 1 . Saturation Properties . APPENDIX VI1 . COMPARISON OF RESULTS WITH VALUES OBTAINED BY INTERPRETATION OF OTHER EXPERIMENTAL DATA . 54 56 56 59 59 62 62 64 66 66 67 67 67 67 69 70 70 70 71 72 ii GPA TP-b 82 ES4 3824b99 0030979 TLb LIST OF TABLES . Table 1. Composition of Propane 2. Thermodyna
12、mic Data for Propane. Values at the Temperatures of Isothermal and Isenthalpic Determinations. b. T = 160.6 F. 3, Thermodynamic Properties of Saturated Propane. 4. Thermodynamic Data for Propane in the Single Phase Region,. 11.1. Comparison of Values of Latent Heat of Vaporization as Generated from
13、Experimental Data by Yesavage (68) and Giszczak (26). AII.2. Comparison of Smoothed Enthalpy Values of Giszczak (26) with Experimental Results of Yesavage (68) at 700 psia. AII.3. Comparison of Smoothed Enthalpy Values of Giszczak (26) with Experimental Results of Yesavage (68) at 160.6 F AII.4. Com
14、parison of Smoothed Enthalpy Values at 2000 psia as Generated by Yesavage (68) and Giszczak (26). AII.5. Comparison of Enthalpy Values at -150 F as Generated by Yesavage (68) and Giszczak (26). A111.1. Sources of Volumetric Data Used in This Study (26) AIV.l. Temperature Intervals Used in Making Ent
15、ropy Difference Calculations at 600 psia. AIV.2. Comparison of Entropy Differences in the Overlapping Temperature Region at 600 psia Page 4 17 18 19 20 21 22 45 50 51 52 52 55 57 50 iii GPA TP-6 82 = 3824699 0010780 738 AVI.1. Ideal Gas Entropy Values at 25 C and Atmos- pheric Pressure (66) for the
16、Components in the Propane Sample Used by Yesavage(68). 68 AVI.2. Second Viria1 Coefficients at 25 C 69 iv GPA TP-6 82 3824699 0010981 b74 = LIST OF FIGURES Figure Page 1. Temperatures and Pressures of Calorimetric Determinations on Propane by Yesavage(68). 3 2. P-T-S Diagram for Propane: -280 T 3 50
17、0 F; 25 i P L 2000 psia 7 3. P-T-H-S Diagram for Propane: -280 3 T 3 500 F; 15 I P 2000 psia 8 AI.1. Ranges of PVT Data Used in Preparation of Pressure-Temperature-Enthalpy-Entropy Table for Propane. 43 AII.1. Coordinate System Generated as an Aid in Smoothing Data in the Vincinity of the Critical p
18、oint. 47 AII.2. Comparison of Smoothed Enthalpy Values of Giszczak (26) with Experimental Results of Yesavage (68) at P = 700 psia 49 AIV.1. Preliminary Thermodynamic Consistency Checks for Entropy. 60 AV.1. Adjusted Enthalpy Values Compared to those Reported by Yesavage (68) 63 AV.2. Check of Therm
19、odynamic Consistency of Entropy Differences 65 AVII.l. Comparison of Isobaric Entropy Differences Calculated by Powers (57) using Data of Ernst (20,211 with Those Obtained in This Work. 73 V GPA TP-6 82 3824699 0030982 500 INTRODUCTION There is a continuing need for accurate values of thermodynamic
20、properties of materials which are obtained by careful evaluation of all existing experimental data using rigorous and precise methods. In the case of pure compounds such as propane, compilations of this type find immediate applications i.e. as in the design of refrigeration systems. Perhaps of more
21、importance, reliable values serve as an important basis for evaluating methods of prediction methods which are vital to modern engineering design. Therefore the purposes of the study which served as the basis for this Research Report were to compile the then available experimental data on the thermo
22、dynamic properties of propane, evaluate the data in so far as possible, and make use of these data to prepare tables and diagrams of the thermodynamic properties of propane which would be thermo- dynamically self consistent, represent published data within experimental limits and, hopefully, which w
23、ould be accurate as well as precise. DATA CONSIDERED IN THE STUDY Efforts were made to search out all of the thermo- dynamic data on propane that were available at the time this study was initiated. These data included both calorimetric and volumetric categories. Details are given in Appendix I. In
24、brief, types and sources of calorimetric data used in the study include: 1. Latent Heats of Vaporization (15,29,38,60,681 2. Heat Capacities of Saturated Liquid (5,381 3. Isobaric Heat Capacities (C 1 a. b. Gaseous and dense phases at elevated pressures Gaseous phase at atmospieric pressure (14,20,
25、21,40,63 1 (20,21,23,68) 4. Isothermal throttling coefficients ($1 (67,681 5. Joule-Thomson Coefficients (11) (61,681 Volumetric data (including the critical properties of propane) were used to supplement the calorimetric data. (3, 16,18,34,58,621. Several prior compilations of thermo- dynamic data
26、were noted during the search. (1,6,9,15,26, 42,59,64,65,66,68,69) The study summarized in this Research Report was based principally on the results of two prior investigations: 1 GPA TP-b 82 111 3824677 0030783 447 W 1. 2. AS Yesavage (68) obtained calormetric data on the effects of both pressure an
27、d temperature on the enthalpy of propane. (This experimental study was also sponsored by the Gas Processors Association). The range of his data is represented in Figure 1. He made available a P-T-H diagram and associated table of values. The reported enthalpy values extended from -280 to +500 F at p
28、ressures up to 2000 psia. Giszczak (26) worked to improve the interpretation of these data. Details of such improvements are given in Appendix II even though the work of Giszczak (26) was completed before the present study was initiated. In brief Giszczak: a. Used several techniques to improve inter
29、pre- tation of the basic calorimetric measurements in the critical region and at the boundaries of the two phase region. b. Smoothed enthalpy values in the liquid region. a result of the extensive efforts that had been made to obtain and interpret calorimetric data to yield enthalpy values of except
30、ional accuracy and consistency, primary emphasis has been placed on utilizing the smoothed P-T-If values for propane as obtained by Giszczak (261, making use of published volumetric data to obtain values of other thermodynamic properties including specific volume, y, density, pI fugacity, f, and spe
31、cific entropy, S. IMPURITIES Experimental results for “pure compounds“ are always obtained with a mixture of compounds of which the major constituent is the pure compound. Naturally the impurities present and their relative abundance vary from mixture to mixture and from investigator to investigator
32、. In this study principal emphasis in obtaining smoothed values was placed on calorimetric data and the primary source of such data is from the thesis of Yesavage (68). Therefore the tables and diagrams presented in this report are thought to be representative of a mixture containing 0.9975 mole fra
33、ction propane with impurities as given in Table 1. PREPARATION OF TABLES AND DIAGRAMS OF THE THERMODYNAMIC PROPERTIES OF PROPANE Procedures This study is similiar in many ways to a previous one by Bhirud and Powers (6) that was also sponsored by GPA. The 2 GPA TP-6 82 3824699 0030784 383 H v) M . O
34、O QI n r- n (o M I I VlSd 38nSS3Ud O O rc) + O 0 (u + O + O VI + O a - 0 + 8 + O 3 n I 3 2 I 3 n - I 3 3 N 9 r) v I O c O 8 rl a) k 3 F .rl Fr 3 . GPA TP-6 82 = 3824699 0030985 2LT Table 1. COMPOSITION OF PROPANE _ Component Mole Fraction Methane o . 0002 Ethane O . 0003 P r opy 1 ene 0.0001 Propane
35、 O . 9975 Nitrogen 0.0015 Oxygen 0.0004 1 . O000 accuracy 1. , 2. 3. 4. general procedures are described in detail in that report and will not be repeated here. In this study a seven step process was followed to produce values of thermodynamic properties in graphical and tabular form that satisfy th
36、e requirements of thermodynamic consistency and, at the same time, are in agreement with the original smoothed calori- metric and volumetric values within the apparent limits of of the experimental data. In brief; As discussed in a preceding section, the P-T-fi values of Giszczak (26) based on the e
37、xperimental data of Yesavage (68) were utilized as a starting point. (For details see Appendix II.) Volumetric data from the literature were evaluated and used to generate smoothed preliminary values of the specific volume, Y, and therefore preliminary values of the compressibility factor, 2, and th
38、e fugacity, f. (Details are given in Appendix III.) Preliminary values of specific entropy, S, were calculated using procedures designed to make maximum use of the calorim-etric data i.e. derivative functions based on the volumetric data were employed. (Details including equations used are presented
39、 in Appendix IV.) Checks were made of the thermodynamic consistency of the individual entropy differences that were calculated. On this basis and reconsidering the calorimetric and volumetric data used in the calculations it was decided that both types of data (smoothed values of specific enthalpy a
40、nd volume) 4 GPA TP-b 82 E3 3824b OOLOb 156 required further adjustment. 5. The adjustments of enthalpy values were made independently of those of the volumetric data. (See Appendix V for details.) First, the smoothed enthalpy values were adjusted within the limits of experimental error V0.5 percent
41、 for isobaric data and 21.5 percent for isothermal data) so as to reduce the inconsistency of the entropy values while maintaining the thermodynamic consistency of the enthalpy values. values were then used with the yet to be corrected values of volumetric data to generate an improved set of entropy
42、 values. The thermodynamic consistency of these new entropy values were then determined. (Details are given in Appendix V.) These adjusted enthalpy 6. It was then found possible to obtain values of entropy that are entirely self consistent by adjusting the volumetric values within the apparent accur
43、acy of such data (11%). (See Appendix V for details.) 7. The smoothed and consistent values of specific enthalpy, volume and entropy were then presented in both graphical and tabular form together with values of associated thermodynamic properties; the fugacity, f, and the isothermal throttling coef
44、fi- cient $ = taH/aP), . In preparing these tables the enthalpy of each pure component was taken to be zero in the saturated liquid state at -280 F to be consistent with results presented previously. (6,44 - 48) The entropy of each pure component in the mixture (See Table I) was taken to be zero as
45、a perfectly oriented crystal at absolute zero on the thermodynamic scale of temperature to be consistent with the third law of thermodynamics. Thus, the entropy values reported are in absolute terms according to the third law. See Bhirud and Powers (6) for details. Results A. Tables of Thermodynamic
46、 Values Tables 2-4 contain the final values of the thermody- namic properties of propane obtained in the course of this study, These tables are located following the body of the report starting with page 17. Table 2 lists values corresponding to experimental conditions encountered in the isothermal
47、and isenthalpic calorimetric studies of Yesavage (68). Table 2 contains values of the isothermal throttling coefficient,$ , and the fugacity, f, in addition to values of a, Y, and S for designated pressures up to 2000 psia at temperatures of the isothermal measurments. (Table 2a, 21.2 F; 2b, 160.6 F
48、; 2c, 201.0 F and 2d, 250.0 P.) 5 GPA TP-6 82 3824679 ODL0787 O72 Table 3 contains enthalpy and entropy values for propane as saturated liquid and vapor at atmospheric Pressure, at the critical pressure (617 psia) and at inter- ;als of 50 psia in between. included. Values of A %ap and %ap are Table
49、4 contains values of and S in the single phase at selected pressures up to 2000 psia at intervals of 10 F from -280 to +SOO F. Values are also included at tempera- tures corresponding to isothermal and isenthalpic experi- ments (21.2, 160.6, 201.0 and 250.0 FI. B. Representation in Graphical Form P-T-S and P-T-S-H diagrams prepared from the values listed in Tables 2 - 4 are presented here as Figures 2 and 3 respectively. Temperature is represented parametrically in intervals of 20 F. Values of II can be read to better than 1 Btu/lb and S can be interpolated between
