1、Gas Process ors Association GPA TP-7 82 3824699 001l1055 231 = . Technical Publication TP-7 Excess Enthalpy Experimental Data Binary Systems: Water+Hydrogen Water+ Methane Water + N trogen Water+Argon C. J. Wormald C. N. Colling University of Bristol Bristol June, 1982 1812 First Place Tulsa, Okla.
2、74103 Phone: 918/582-5112 GPA TP-7 2 I 3824699 OOLL05b L7B = FOREWORD The GPA Enthalpy Steering Committee has been having difficulty in finding operating calorimeters and in turn investigators to obtain ;experimental enthalpy measurements. In 1979 the Steering Committee contacted Dr. C. J. Wormald,
3、University of Bristol, regarding a research project to obtain enthalpy data by means of calorimeteric measurements. A contract to obtain data on various mixtures of water, COZ, H2, and N2 was made. and iC4. contacted. Since these systems are of interest to our people, he agreed to consolidate all th
4、e data he had obtained earlier for us to publish as a GPA Technical Publication. Later work will include systems with C2, C3, Dr. Wormald had already completed study of several binary systems when We feel these data will be of value and interest to the industry. Our thanks are extended to Dr. Wormal
5、d and his associates for preparing this article and permitting us to distribute it to our membership. dari Sutton, Secretary Gas Processors Association TABLE OF CONTENTS LIST OF TABLES . ii ACKNOWLEDGEMENTS . iii ABSTRACT 1 INTRODUCTION 2 THERMODYNAMICS OF GASEOUS MIXTURES AT MODERATE DENSITIES . .
6、3 SCOPE OF THE MEASUREMENTS 4 NOTE ON THE PRESENTATION OF THE EXPERIMENTAL RESULTS 5 METHOD FOR ANALYSIS OF THE RESULT AT 0.101 MPa . 6 RESULTS OF HEAT LEAK TESTS ON THE HIGH PRESSURE FLOW CALORI- METER 7 THERMODYNAMIC TESTS ON THE HIGH PRESSURE MEASUREMENTS 9 FITTING THE HE RESULTS TO AN EQUATION .
7、 13 RESULTS OF MEASUREMENTS AT 0.101MPa 15 RESULTS OF THE HIGH PRESSURE HE MEASUREMENTS 22 METHOD FOR THE CALCULATION OF COMPRESSION FACTORS 50 REFERENCES . 52 i GPA TP-7 82 3824697 OOLLO58 T40 I LIST OF TABLES COEFFICIENTS OF THE HE (p. T) EQUATION . 14 THE EXCESS ENTHALPY OF NITROGEN + WATER AT 10
8、1.3 kPa . 16 THE EXCESS ENTHALPY OF ARGON + WATER AT 101.3 Ha . 17 THE EXCESS ENTHALPY OF HYDROGEN + WATER AT 101.3 kPa . 18 THE EXCESS ENTHALPY OF METHANE + WATER AT 101.3 kPa 19 20 THE EXCESS ENTHALPY OF NITROGEN + WATER AT HIGH PRESSURES . 23 THE EXCESS ENTHALPY OF ARGON + WATER AT HIGH PRESSURES
9、 32 THE EXCESS ENTHALPY OF HYDROGEN + WATER AT HIGH PRESSURES . 38 THE EXCESS ENTHALPY OF METHANE + WATER AT HIGH PRESSURES . 44 ANALYSIS OF THE HE MEASUREMENTS AT 101.3 kPa . ii GPA TP-7 82 El 3824699 OOLLO59 987 Acknowledgements Measurements of the excess enthalpy of mixturescontaining steam were
10、begun in Bristol in 1974 funded by the British Gas Corporation. would like to express my gratitude to the Corporation for its support and encouragement. I Especial thanks are due to my co-worker Nicholas Colling for sharing with me the hard work of developing and testing several designs of calorimet
11、er and associated apparatus. When a good design had been evolved Mr. Colling went on to make some excellent measurements. Since September 1980 the work has been funded by GPA under project number 773-B-80, and the measurements have been carried out by Mr. Alexander Cellars. support. I am most gratef
12、ul to GPA for its interest and Essential to the analysis of the high pressure measurements are values of the excess enthalpy obtained atpressures around atmospheric. These measurements were made using a flow mixing calorimeter especially designed to operate at low pressures. My thanks to my co-worke
13、rs Joe Doyle, Peter Richards, Trevor Yerlett, Gareth Smith and Charles Patterson for their hard work with these measurements. iii GPA TP-7 82 382Yb 00110b0 bT Ab s tr a c t Measurements of the excess enthalpy HE of binary mixtures of water vapour + hydrogen, + methane, + nitrogen and + argon have be
14、en made using continuous flow isothermal mixing calorimeters. measurements extend over the temperature range 373.2 to 698.2 K at pressures from 0.101 to 12 MPa. The overall accuracy of the measurements is between 1.5 and 2 percent. The Measurements in the region of atmospheric pressure were made ove
15、r the temperature range 373.2 to 423.2 K using a differential flow mixing calorimeter especially designed for operation at low pressures. Analysis of the low pressure HE measurements yields values of the cross term isothermal enthalpy-pressure coefficient 4 and the cross term second viria1 coefficie
16、nt B 12 12 Measurements at pressures up to approximately 12 MPa and at temperatures from 458.2 to 698.2 K were made using a carefully tested flow mixing calorimeter especially designed for dense gases. The excess enthalpies obtained at high pressures have been shown to be thermodynamically consisten
17、t with the low pressure measurements. The excess enthalpies obtained for each of the mixtures at x = 0.5 have been fitted to simple equations in powers of the pressure where the coefficients are functions of temperature. The method by which compression factors may be calculated is out 1 ined. 1 GPA
18、TP-7 82 m 3824b99 0011ObL 535 m 1.1 Introduction Despite the extensive industrial use of steam as a reactant, in distillation plant, as a component of process streams, and as a product of combustion, thermodynamic data on mixtures containing steam are almost non existent. At high densities the phase
19、 boundaries of several (water + hydrocarbon) mixtures have been determined I ,2. densities the cross term second virial coefficient B has been obtained from measurements of the solubility of water in compressed gases 3,4. The primary source of information about mixture properties is pVT measurement,
20、 but for mixtures containing water vapour large adsorption errors make accurate work almost impossible. the saturation pressure or at low temperatures. At low 12 The problem is worst near An alternative source of thermodynamic information on mixtures containing steam is the use of flow calorimetry.
21、of flow calorimeter the quantities that can be measured are the heat capacity of the mixture, the enthalpy of the mixture, the isothermal enthalpy-pressure coefficient, and the enthalpy of mixing. The latter is not only a direct measurement of an excess quantity, but is experimentally easier to obta
22、in than the others. Using different types This report contains results of measurements of the excess enthalpy of water vapour + hydrogen, + methane, + nitrogen and + argon. The measurements span the temperature range 373.2 to 698.2 K at pressures from 0.101 to 12 MPa. The measurements on water + nit
23、rogen and water + argon at O. 101 MPa have been published 5,6. hydrogen and water + methane at 0.101 MPa have only just been completed. Measurements on water + Only brief reports of the high pressure measurements have so far been published 7,8,9. n-heptane) vapour at high pressures. Reference 5 incl
24、udes numerical data for (water + heptane) vapour at low pressures. Reference 9 includes graphical data for (water + Preliminary analysis of the high pressure measurements showed the importance of obtaining an additional set of measurements at low pressures to as low a temperature as possible. Analys
25、is of the low pressure measurements using the virial equation of state allows the high pressure results to be checked for thermodynamic consistency. In this publication experimental results are reported and a thermodynamic analysis of the measurements is made. to the analysis are possible the presen
26、t aim is to show how the analysis While improvements 4 2 GPA TP-7 82 3824679 0011062 471 should be done and how checks on the consistency of the measurements can be made. 1.2 Thermodynamics of gaseous mixtures at moderate densities The properties of gases at the densities used in this work can be de
27、scribed using the virial equation of state truncated after the p 4 term. (1) pV = RT + Bp + Cp + Dp3 + Ep 4 The coefficients B, C, U and E are related to the virial coefficients By Cy D and E through the equations B = B (2) CI = (c - B)/RT, (3) (4 1 D = (D - 3BC + 2B3)/(RT) 2 , (5) E = (E - 4DB - 2C
28、2 + 10CB2 - 5B4)/(RT) 3 E The excess volume V is defined by the equation VE = v -xv -xv (6) m 11 22 where V the molar volume of the mixture. and higher order terms in (I) to be neglected and V 1 2 are the molar volumes of the pure components and Vm is At pressures low enough for the p 2 = RT/p + Bm
29、, m where Bm = x 2 B + 2x x B + x 2 B I II 1 2 12 2 22 Equation (6) can now te written VE = x1x2(2BI2 - BI1 - BZ2 . It follows that and HE = GE - T(dGE/dT) = x12p(2$12 - c$Ill - c$122) , where i$ = B - TdB/dT , (1 1) is the isothermal enthalpy-pressure coefficient in the limit of zero pressure, i.e.
30、 $ = (3H/3p)T Lim p-to. 3 GPA TP-7 82 m 3824699 0011063 308 m E Including terms up to p4 the equation for the excess enthalpy H is + p 2 /2(Ck - TdCm/dT) - x (C - TdC;/dT) - x2(C; - TdC;/dT) 11 The first two terms in equation (12) are particularly important, and can be written in the form Equation (
31、12) is of the form + 6p4 (19) HE = ap + P2 + YP where a is given by equation (13), is the sum of (14) and (15) and y and 6 are functions of temperature related to the viria1 coefficients. 2.1 Scope of the measurements Excess enthalpies of mixtures of steam + hydrogen, + methane, + nitrogen and + arg
32、on have been measured over the range of temperature 373.2 to G9S.2 K atpressures from atmospheric to approximately 12 MPa. An isothermal flow calorimetric technique was employed. As the experimental requirements for making measurements at 373 K and low pressures are quite different from the requirem
33、ents at 698 K and high pressures, two flow calorimeters have been used. Details of the low pressure mixing calorimeter used to make measurements in the region of atmospheric pressure and at temperatures around 373 K have been published IO. measurements has been described in outline 8. calorimeters h
34、ave been carried out. The apparatus used for the high pressure high temperature Extensive tests on both It has been established that mixing 4 GPA TP-7 82 m 3824699 O011064 244 = is complete, heat leaks are negligible, the Joule-Thomson effect is negligible, and that the results are independent of te
35、mperature, pressure and flow rate. High pressure measurements for each mixture have been made at 9 temperatures from 448.2 to 698.2 K. of water (647.3 K) the measurements were made as near to saturation pressure as was feasible. above the critical temperature of water and extend to approximately 12
36、ma. While the majority of the measurenents have been made at compositions very close to x = 0.5, some measurements of the composition dependence of HE at fixed T and p have been made for each mixture. Below the critical temperature The measurements at 648.2 and 698.2 K are 2.2 Note on the presentati
37、on of the experimental results Excess enthalpies obtained using the low pressure mixing calorimeter at 0.101 MPa are listed in tables 4.1 to 4.4. Excess enthalpies obtained using the high pressure mixing calorimeter are listed in tables 5.1 tu 5 MPa 0.35 0.45 0.58 0.65 0.71 0.93 1 .O5 1.14 1.55 1.65
38、 i .83 2.02 2.17 2.54 O. 72 1.55 1.83 2.86 2.93 3.84 4.21 4.24 4.97 5.55 HE -1 J mol 98.5 142.2 163.5 175.9 217.5 281 .O 195.0 21 I .4 299.7 323. i 359.2 406.3 463.4 553.9 88.4 194.7 239.1 389.2 403.2 580.8 635.8 686.4 854.1 954.3 23 GPA TP-7 82 3824699 OOLLO83 LTb = Run 3 15 314 313 312 329 31 1 31
39、0 153 122 152 118 151 114 150 134 149 130 309 1 IO 30 8 101 307 250 306 T - K %2O 574.2 0.501 574.3 0.500 574.5 0.500 574.3 0.499 573.1 0.500 574.3 0.499 574.0 0.499 595.6 0.501 597.1 0.507 595.5 0.501 596.8 0.504 595.7 0.502 595.4 0.502 595.9 0.503 596.5 0.499 596.1 0.500 596.4 0.506 597.0 0.500 59
40、6.4 0.499 597.1 0.499 596.2 0.505 597.5 0.499 597.8 0.501 597.3 0.501 TABLE IV - contd P P/f p J mol- MPa -1 -1 mo1 s Js T = 573.2 8.046 O. 534 66.4 0.72 8.024 1.786 222.6 2.10 8.021 3.308 412.4 3.51 8.012 5.155 643.4 4.89 5.548 4.536 817.6 5.62 7.991 7.474 935.3 6.31 7.974 10.181 1277 7.72 6.762 4.
41、979 6.765 5.007 6.751 5.033 6.743 5.072 6.785 4.996 7.987 7.607 8.006 5.021 7.982 3.969 7.969 T = 598.2 K 0.516 76.3 0.80 0.71 1 142.8 1.47 1.366 201.9 2.16 1.370 273.6 2.86 2.389 353.9 3.53 2.193 435.7 4.24 3.640 539.8 5.00 2.994 590.3 5.62 4.895 721.4 6.31 3.794 759.5 6.96 7.914 990.8 7.69 8.292 1
42、090 8.37 10.38 1296 9.10 6.604 1315 9.74 13.18 1651 10.51 7.509 1892 11.13 15.02 1885 11.17 HE J m0i-l 66.8 224.3 416.6 649.5 816.9 945.1 1287 75.3 141.9 198.6 271.1 348. O 427.2 530.8 582.1 709.1 747.0 980.9 1075 1284 1289 1640 1 885 1869 24 GPA TP-7 82 I 3824699 OOLL084 032 H Run 161 71 160 44 64
43、159 48 i 58 157 75 52 305 227 304 263 222 297 296 295 294 293 292 29 1 30 1 290 276 X T K - H2 647.8 0.497 647.3 0.499 647.9 0.498 648.7 0.501 646.7 0.498 648.1 0.497 646.9 0.498 648.2 0.495 648.0 0.494 647.8 0.504 646.8 0.503 648.6 0.499 650.1 0.499 649.5 0.495 647.9 0.501 651.3 0.500 697.4 0.498 6
44、98-0 0.501 697.5 0.499 698.0 0.500 698.0 0.500 698.9 0.501 699.6 0.499 698.3 0,498 699.2 0.502 697.8 0.500 TABLE IV - contd f P P/f - P HE MPa J mol- -1 -1 -1 mo1 c Js J mol T = 648.2 K 6.817 5.066 6.813 5.052 5.075 6.835 5 .O84 6.854 6.876 5.030 5.035 8.009 6.919 8.014 8.736 6.806 0.654 0.561 1.304
45、 1.119 1.676 2.112 2.191 2.917 3.765 2.848 3.508 6.567 6.585 8.707 i 1.76 8.752 7 983 7.977 7.972 8.035 8.034 7.941 7.999 7 I 998 8.026 5.554 T = 698.2 K 0.537 1.207 1.917 2.678 3.521 4.409 5.295 5.781 6.234 5.177 96.0 1.41 95.7 110.7 1.47 110.3 191.4 2.82 191.1 221.5 2.89 222.2 330.2 4.20 327.7 309
46、.0 4.27 308.9 430.9 5.48 427.8 425.6 5,65 425.7 547.6 7.06 547.0 566.2 7.06 564.9 690.1 696.7 8.31 820.0 9.06 822.1 951.8 10.02 964 1086 11.13 1097 1346 12.58 1343 1286 12.58 1316 67.3 1.48 66.9 151.3 2.86 151.2 240.4 4.24 239.6 333.3 5.62 330.0 438.3 7 .O7 437.8 555.2 8.48 557.2 662.0 9.82 667.0 722.7 10.44 723.1 777.8 11.13 782.2 932.1 12.59 930.1 25
