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Designation: D 1142 – 95 (Reapproved 2000)
Standard Test Method for
Water Vapor Content of Gaseous Fuels by Measurement of Dew-Point Temperature1 This standard is issued under the fixed designation D 1142; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.
2.1.1 saturated water vapor or equilibrium water–vapor content—the water vapor concentration in a gas mixture that is in equilibrium with a liquid phase of pure water that is saturated with the gas mixture. When a gas containing water vapor is at the water dew-point temperature, it is said to be saturated at the existing pressure. 2.1.2 specific volume—of a gaseous fuel, the volume of the gas in cubic feet per pound. 2.1.3 water dew-point temperature—of a gaseous fuel, the temperature at which the gas is saturated with water vapor at the existing pressure.
1. Scope 1.1 This test method covers the determination of the water vapor content of gaseous fuels by measurement of the dewpoint temperature and the calculation therefrom of the water vapor content. NOTE 1—Some gaseous fuels contain vapors of hydrocarbons or other components that easily condense into liquid and sometimes interfere with or mask the water dew point. When this occurs, it is sometimes very helpful to supplement the apparatus in Fig. 1 with an optical attachment2 that uniformly illuminates the dew–point mirror and also magnifies the condensate on the mirror. With this attachment it is possible, in some cases, to observe separate condensation points of water vapor, hydrocarbons, and glycolamines as well as ice points. However, if the dew point of the condensable hydrocarbons is higher than the water vapor dew point, when such hydrocarbons are present in large amounts, they may flood the mirror and obscure or wash off the water dew point. Best results in distinguishing multiple component dew points are obtained when they are not too closely spaced. NOTE 2—Condensation of water vapor on the dew-point mirror may appear as liquid water at temperatures as low as 0 to −10°F (−18 to −23°C). At lower temperatures an ice point rather than a water dew point likely will be observed. The minimum dew point of any vapor that can be observed is limited by the mechanical parts of the equipment. Mirror temperatures as low as −150°F (−100°C) have been measured, using liquid nitrogen as the coolant with a thermocouple attached to the mirror, instead of a thermometer well.
3. Significance and Use 3.1 Generally, contracts governing the pipeline transmission of natural gas contain specifications limiting the maximum concentration of water vapor allowed. Excess water vapor can cause corrosive conditions, degrading pipelines and equipment. It can also condense and freeze or form methane hydrates causing blockages. Water–vapor content also affects the heating value of natural gas, thus influencing the quality of the gas. This test method permits the determination of water content of natural gas. 4. Apparatus 4.1 Any properly constructed dew-point apparatus may be used that satisfies the basic requirements that means must be provided: 4.1.1 To permit a controlled flow of gas to enter and leave the apparatus while the apparatus is at a temperature at least 3°F above the dew point of the gas. 4.1.2 To cool and control the cooling rate of a portion (preferably a small portion) of the apparatus, with which the flowing gas comes in contact, to a temperature low enough to cause vapor to condense from the gas. 4.1.3 To observe the deposition of dew on the cold portion of the apparatus. 4.1.4 To measure the temperature of the cold portion on the apparatus on which the dew is deposited, and
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Terminology 2.1 Definitions of Terms Specific to This Standard: 1 This test method is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved Feb. 15, 1995. Published April 1995. Originally published as D 1142 – 50. Last previous edition D 1142 – 90. 2 Several pieces of apparatus for this purpose are commercially available. Information concerning this apparatus is available from ASTM Headquarters.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
D 1142 – 95 (2000)
FIG. 1 Bureau of Mines Dew-Point Apparatus
refrigerant such as liquid butane, propane, carbon dioxide, or some other liquefied gas in the chiller, G. The refrigerant is throttled into the chiller through valve H and passes out at J. The chiller body is made of copper and has brass headers on either end. The lower header is connected with the upper header by numerous small holes drilled in the copper body through which the vaporized refrigerant passes. The chiller is attached to the cooling rod, F, by means of a taper joint. The temperature of the target mirror, C, is indicated by a calibrated mercury-in-glass thermometer, K, whose bulb fits snugly into the thermometer well. Observation of the dew deposit is made through the pressure-resisting transparent window, E. 4.2.1 Note that only the central portion of the stainless steel target mirror, C, is thermally bonded to the fitting, I, through which C is cooled. Since stainless steel is a relatively poor thermal conductor, the central portion of the mirror is thus maintained at a slightly lower temperature than the outer portion, with the result that the dew first appears on the central portion of the mirror and its detection is aided materially by the contrast afforded. The arrangement for measuring the temperature of the target mirror, C, also should be noted. The temperature is read with a thermometer or RTD, K, inserted in the cooling rod, F, so that the bulb of the temperature measuring device is entirely within the thermometer well in fitting, I. The stud to which the stainless steel mirror is silver-soldered is a part of the base of the thermometer well, and as there is no metallic contact between the thermometer
4.1.5 To measure the pressure of the gas within the apparatus or the deviation from the known existing barometric pressure. 4.1.6 The apparatus should be constructed so that the “cold spot,” that is, the cold portion of the apparatus on which dew is deposited, is protected from all gases other than the gas under test. The apparatus may or may not be designed for use under pressure. 4.2 The Bureau of Mines type of dew-point apparatus3 shown in Fig. 1 fulfills the requirements specified in 4.1. Within the range of conditions in Section 1, this apparatus is satisfactory for determining the dew point of gaseous fuels. Briefly, this apparatus consists of a metal chamber into and out of which the test gas is permitted to flow through control valves A and D. Gas entering the apparatus through valve A is deflected by nozzle B towards the cold portion of the apparatus, C. The gas flows across the face of C and out of the apparatus through valve D. Part C is a highly polished stainless steel “target mirror,” cooled by means of a copper cooling rod, F. The mirror, C, is silver-soldered to a nib on the copper thermometer well fitting, I, which is soft-soldered to the cooling rod, F. The thermometer well is integral with the fitting, I. Cooling of rod F is accomplished by vaporizing a
3 Deaton, W. M., and Frost, E. M., Jr., “Bureau of Mines Apparatus for Determining the Dew Point of Gases Under Pressure,” Bureau of Mines Report of Investigation 3399, May 1938.
2
D 1142 – 95 (2000) conditions as nearly as possible. The most satisfactory method is to cool or warm the target mirror stepwise. Steps of about 0.2°F (0.1°C) allow equilibrium conditions to be approached closely and favor an accurate determination. When dew has been deposited, allow the target mirror to warm up at a rate comparable to the recommended rate of cooling. The normal warming rate usually will be faster than desired. To reduce the rate, “crack” valve H momentarily at intervals to supply cooling to the cooling tube, F. Repeat the cooling and warming cycles several times. The arithmetic average of the temperatures at which dew is observed to appear and disappear is considered to be the observed dew point.
well and the cooling tube, other than through its base, the thermometer or RTD indicates the temperature of the mirror rather than some compromise temperature influenced by the temperature gradient along the cooling tube as would be the case if this type of construction were not used. The RTD will include suitable electronics and display. 4.2.2 Tests with the Bureau of Mines type of dew-point apparatus are reported3 to permit a determination with a precision (reproducibility) of 60.2°F (60.1°C) and with an accuracy of 60.2°F (60.1°C) when the dew-point temperatures range from room temperature to a temperature of 32°F (0°C). It is estimated that water dew points may be determined with an accuracy of 60.5°F (0.3°C) when they are below 32°F (0°C) and not lower than 0°F (−17.8°C), provided ice crystals do not form during the determination.
NOTE 3—If the water–vapor content is to be calculated as described in 6.2, the gas specimen should be throttled at the inlet valve, A, to a pressure within the apparatus approximately equal to atmospheric pressure. The outlet valve may be left wide open or restricted, as desired. The pressure existing within the apparatus must, however, be known to the required accuracy.
5. Procedure 5.1 General Considerations—Take the specimen so as to be representative of the gas at the source. Do not take at a point where isolation would permit condensate to collect or would otherwise allow a vapor content to exist that is not in equilibrium with the main stream or supply of gas, such as the sorption or desorption of vapors from the sampling line or from deposits therein. The temperature of the pipelines leading the specimen directly from the gas source to the dew-point apparatus, and also the temperature of the apparatus, shall be at least 3°F (1.7°C) higher than the observed dew point. The determination may be made at any pressure, but the gas pressure within the dew-point apparatus must be known with an accuracy appropriate to the accuracy requirements of the test. The pressure may be read on a calibrated bourdon-type pressure gage; for very low pressures or more accurate measurements, a mercury-filled manometer or a dead-weight gage should be used. 5.2 Detailed Procedure for Operation of Bureau of Mines Dew-Point Apparatus—Introduce the gas specimen through valve A (Fig. 1), opening this valve wide if the test is to be made under full source pressure (Note 3), and controlling the flow by the small outlet valve, D. The rate of flow is not critical but should not be so great that there is a measurable or objectionable drop in pressure through the connecting lines and dew-point apparatus. A flow of 0.05 to 0.5 ft3/min (1.4 to 14 L/min) (measured at atmospheric pressure) usually will be satisfactory. With liquefied refrigerant gas piped to the chiller throttle valve, H, “crack” the valve momentarily, allowing the refrigerant to vaporize in the chiller to produce suitable lowering in temperature of the chiller tube, F, and target mirror, C, as indicated by the thermometer, K. The rate of cooling may be as rapid as desired in making a preliminary test. After estimating the dew-point temperature, either by a preliminary test or from other knowledge, control the cooling or warming rate so that it does not exceed 1°F/min (0.5°C/min) when this temperature is approached. For accurate results, the cooling and warming rates should approximate isothermal
6. Calculation 6.1 If an acceptable chart showing the variation of watervapor content with saturation or water dew-point temperatures over a suitable range of pressures for the gas being tested is available, the water-vapor content may be read directly, using the observed water dew-point temperature and the pressure at which the determination was made. 6.2 If such a chart is not available, the water–vapor content of the gas may be calculated from the water dew-point temperature and the pressure at which it was determined (see Note 3), as follows:
FIG. 2 Equilibrium Water Vapor Content of Natural Gases
3
D 1142 – 95 (2000) W 5 w 3 10 6 3 ~Pb/P 3 ~T/T b!!
6.3 A correlation of the available data on the equilibrium water content of natural gases has been reported by Bukacek.5 This correlation is believed to be accurate enough for the requirements of the gaseous fuels industry, except for unusual situations where the dew point is measured at conditions close to the critical temperature of the gas. The correlation is a modified form of Raoult’s law having the following form:
(1)
where: W = lb of water/million ft3 of gaseous mixture at pressure Pb and temperature Tb; w = weight of saturated water vapor, lb/ft3, at the water dew-point temperature, that is, the reciprocal of the specific volume of saturated vapor (see Table 1); Pb = pressure-base of gas measurement, psia; P = pressure at which the water dew point of gas was determined, psia; t = observed water dew-point temperature, °F; T = Rankine (absolute Fahrenheit scale) water dew point, t + 460, at pressure P; and Tb = base temperature of gas measurement, tb + 460.
W 5 ~A/P! 1 B
(2)
where: W = water–vapor content, lb/million ft3; P = total pressure, psia; A = a constant proportional to the vapor pressure of water; and B = a constant depending on temperature and gas composition.
NOTE 4—Example 1: Given: Water dew point = 37°F at 15.0-psia pressure. What is the water–vapor content million ft3 of gas (gas measurement base of 60°F and 14.7-psia pressure)? From Table 1 the specific volume of saturated water at 37°F is 2731.9 ft3/lb, from which: w = (1/2731.9) = 0.000 366 0 lb/ft3 and W = 0.000 366 0 3 10 6 3 (14.7/15.0) 3 [(460 + 37)/(460 + 60)] = 342.8 lb/million ft3 Example 2: Given: Water dew point = 5°F at 14.4 psia. From Table 2, the specific volume of saturated water vapor with respect to ice at 5°F is 11 550 ft3/lb from which Wice, 5F = 0.000 086 6, but the observed water dew point was in equilibrium with subcooled liquid water at 5°F. From Table 2 (data from International Critical Tables4), the vapor pressures of subcooled liquid water and of ice at 5°F (−15°C) are 1.436 mm and 1.241 mm Hg, respectively. Since the vapor pressure of subcooled liquid water is greater than ice at the same temperature, the weight per cubic foot of water vapor in equilibrium with liquid water will be proportionately larger than the value calculated from the specific volume read from the table, which is for equilibrium with ice. Hence, Wliq., 5F = W ice 5F3 (1.436/1.241) = 0.000 086 6 3 1.157 = 0.000 100 2 and W = 0.000 100 2 3 10 6 3 (14.7/14.4) 3 [(460 + 5)/[460 + 60)] = 91.5 lb/million ft3
NOTE 5—Values of B were computed from available data on methane, methane-ethane mixtures, and natural gases.
6.3.1 Table 2 lists values of the constants A and B for natural gases in the temperature range from −40 to 460°F (−40 to 238°C). 6.3.2 Tables 3-5 list values of water–vapor content from −40 to 250°F (−40° to 121°C) and from 14.7 to 5000 psia (101 to 34 475 kPa), covering the range of most natural gas processing applications. 6.3.3 A convenient graphical representation of the data in Tables 3-5 is illustrated in Fig. 2.6 The moisture content values given can be corrected to base conditions other than 14.7 psia (101 kPa) and 60°F (15.5°C) by the same equations given in Table 2. 7. Precision and Bias 7.1 No precision data is available for this test method, however, the Committee is interested in conducting an interlaboratory test program and encourages interested parties to contact the Staff Manager, Committee D03, ASTM Headquarters. 8. Keywords 8.1 gaseous fuels; natural gas 5 Bukacek, R. F., “Equilibrium Moisture Content of Natural Gases,” Research Bulletin 8, Institute of Gas Technology, 1955. Reports work sponsored by the Pipeline Research Committee of the American Gas Association. 6 Complete sets of these charts covering the entire range of pressures and temperatures of Tables 3-5 may be purchased from the Institute of Gas Technology, 1700 S. Mount Prospect Rd., Des Plaines, IL 60018.
4 International Critical Tables, Vol III, National Research Council, McGraw-Hill Book Co., Inc., New York, 1928, pp. 210–211.
4
D 1142 – 95 (2000) TABLE 1 Vapor Pressures and Specific Volumes of Saturated Water Vapor at Various TemperaturesA Vapor Pressure of Liquid Water
Specific Volume of Saturated Water Vapor ft3/lb
Vapor Pressure of Ice
Temperature, °F
Temperature, °F
Vapor Pressure of Liquid Water, psia
Specific Volume of Saturated Water Vapor, ft3/lb
mm Hg
psia
mm Hg
psia
0
1.139
0.022 02
0.958
0.018 52
14 810
1 2 3 4 5
1.195 1.251 1.310 1.373 1.436
0.023 0.024 0.025 0.026 0.027
11 19 33 55 77
1.010 1.063 1.120 1.180 1.241
0.019 0.020 0.021 0.022 0.024
53 56 66 82 00
14 13 12 12 11
080 400 750 140 550
51 52 53 54 55
0.184 0.191 0.199 0.206 0.214
85 82 01 44 11
1 1 1 1 1
644.2 587.6 533.2 480.9 430.6
6 7 8 9 10
1.505 1.573 1.647 1.723 1.807
0.029 0.030 0.031 0.033 0.034
10 42 85 32 94
1.308 1.374 1.446 1.521 1.599
0.025 0.026 0.027 0.029 0.030
29 57 96 41 92
11 10 9 9 9
000 480 979 507 060
56 57 58 59 60
0.222 0.230 0.238 0.247 0.256
03 21 65 36 35
1 1 1 1 1
382.2 335.6 290.9 247.8 206.3
11 12 13 14 15
1.883 1.970 2.057 2.149 2.247
0.036 0.038 0.039 0.041 0.043
41 09 78 56 45
1.681 1.767 1.856 1.950 2.050
0.032 0.034 0.035 0.037 0.039
51 17 89 71 64
8 8 7 7 7
636 234 851 489 144
61 62 63 64 65
0.265 0.275 0.285 0.295 0.305
62 19 06 24 73
1 1 1 1 1
166.4 128.0 091.0 055.4 021.1
16 17 18 19 20
2.345 2.450 2.557 2.607 2.785
0.045 0.047 0.049 0.051 0.053
35 37 44 63 85
2.151 2.260 2.373 2.489 2.610
0.041 0.043 0.045 0.048 0.050
59 70 89 13 47
6 6 6 5 5
817 505 210 929 662
66 67 68 69 70
0.316 0.327 0.339 0.351 0.363
55 70 20 05 26
988.03 956.19 925.51 895.94 867.44
21 22 23 24 25
2.907 3.032 3.163 3.299 3.433
0.056 0.058 0.061 0.063 0.066
21 63 16 79 38
2.740 2.872 3.013 3.160 3.310
0.052 0.055 0.058 0.061 0.064
98 54 26 10 01
5 5 4 4 4
408 166 936 717 509
71 72 73 74 75
0.375 0.388 0.402 0.415 0.430
84 79 14 88 04
839.97 813.48 787.94 763.31 739.55
26 27 28 29 30
3.585 3.735 3.893 4.054 4.224
0.069 0.072 0.075 0.078 0.081
32 22 28 39 68
3.471 3.636 3.810 3.989 4.178
0.067 0.070 0.073 0.077 0.080
12 31 67 14 79
4 4 3 3 3
311 122 943 771 608
76 77 78 79 80
0.444 0.459 0.475 0.490 0.507
61 61 05 94 29
716.62 694.51 673.16 652.56 632.68
31 32 33 34 35
4.397 4.579 ... ... ...
0.085 0.088 0.092 0.096 0.099
02 66 30 07 98
4.373 4.579 ... ... ...
0.084 56 0.088 54 ... ... ...
3 3 3 3 2
453 301.9 178.0 059.2 945.5
81 82 83 84 85
0.524 0.541 0.559 0.577 0.596
11 42 22 53 36
613.48 594.95 577.05 559.76 543.07
36 37 38 39 40
... ... ... ... ...
0.104 0.108 0.112 0.117 0.121
04 23 58 08 73
... ... ... ... ...
... ... ... ... ...
2 2 2 2 2
836.4 731.9 631.7 535.7 443.5
86 87 88 89 90
0.615 0.635 0.656 0.677 0.698
73 63 09 13 74
526.94 511.35 496.29 481.73 467.66
41 42 43 44 45
... ... ... ... ...
0.126 0.131 0.136 0.142 0.147
55 54 70 04 56
... ... ... ... ...
... ... ... ... ...
2 2 2 2 2
355.1 270.3 188.9 110.8 035.8
91 92 93 94 95
0.720 0.743 0.767 0.791 0.816
95 77 22 30 04
454.06 440.91 428.19 415.89 403.99
46 47 48 49 50
... ... ... ... ...
0.153 0.159 0.165 0.171 0.178
28 18 28 59 12
... ... ... ... ...
... ... ... ... ...
1 1 1 1 1
963.8 894.6 828.2 764.4 703.1
96 97 98 99 100
0.841 0.867 0.894 0.921 0.950
44 53 31 80 03
392.48 381.35 370.58 360.15 350.06
A The values for vapor pressure, from 0 to 32°F, were calculated from data in the International Critical Tables.4 All other values were taken from Harr, Gallagher, and Kell, “NBS/NRC Steam Tables,” National Standard Reference Data System, 1984, p. 9. Data on specific volumes of saturated water vapor from 0 to 32°F were obtained from Goff, J. A., and Gratch, S., “ Low-Pressure Properties of Water from −160 to 212°F,” Heating, Piping, and Air Conditioning, Vol 18, No. 2, Feb. 1946, pp. 125–136.
5
D 1142 – 95 (2000) TABLE 2 Values of Constants A and B (Base Conditions = 14.7 psia, 60°F) Temperature, °F
A
B
Temperature, °F
A
B
Temperature, °F
A
B
−40 −38 −36 −34 −32 −30 −28 −26 −24 −22
131 147 165 184 206 230 256 285 317 352
0.22 0.24 0.26 0.28 0.30 0.33 0.36 0.39 0.42 0.45
70 72 74 76 78 80 82 84 86 88
17 18 19 21 22 24 25 27 29 31
200 500 700 100 500 100 700 400 200 100
7.17 7.85 8.25 8.67 9.11 9.57 10.0 10.5 11.1 11.6
180 182 184 186 188 190 192 194 196 198
357 372 390 407 425 443 463 483 504 525
000 000 000 000 000 000 000 000 000 000
74.8 77.2 79.9 82.7 85.8 88.4 91.4 94.8 97.7 101
−20 −18 −16 −14 −12 −10 −8 −6 −4 −2
390 434 479 530 586 648 714 786 866 950
0.48 0.52 0.56 0.60 0.64 0.69 0.74 0.79 0.85 0.91
90 92 94 96 98 100 102 104 106 108
33 35 37 39 42 45 47 50 53 57
200 300 500 900 400 100 900 800 900 100
12.2 12.7 13.3 14.0 14.6 15.3 16.0 16.7 17.5 18.3
200 202 204 206 208 210 212 214 216 218
547 570 594 619 644 671 698 725 754 785
000 000 000 000 000 000 000 000 000 000
104 108 111 115 119 122 126 130 134 139
000 000 000 000 000 000 000 000 000 000
143 148 152 157 162 166 171 177 182 187
0 2 4 6 8 10 12 14 16 18
1 1 1 1 1 1 1 1 2 2
050 150 260 380 510 650 810 970 150 350
0.97 1.04 1.11 1.19 1.27 1.35 1.44 1.54 1.64 1.74
110 112 114 116 118 120 122 124 126 128
60 64 67 71 76 80 84 89 94 100
500 100 900 800 000 400 900 700 700 000
19.1 20.0 20.9 21.8 22.7 23.7 24.7 25.8 26.9 28.0
220 222 224 226 228 230 232 234 236 238
1 1 1 1
816 848 881 915 950 987 020 060 100 140
20 22 24 26 28 30 32 34 36 38
2 2 3 3 3 3 4 4 4 5
560 780 030 290 570 880 210 560 940 350
1.85 1.97 2.09 2.22 2.36 2.50 2.65 2.81 2.98 3.16
130 132 134 136 138 140 142 144 146 148
106 111 117 124 130 137 144 152 160 168
000 000 000 000 000 000 000 000 000 000
29.1 30.3 31.6 32.9 34.2 35.6 37.0 38.5 40.0 41.6
240 242 244 246 248 250 252 254 256 258
1 1 1 1 1 1 1 1 1 1
190 230 270 320 370 420 470 520 570 630
000 000 000 000 000 000 000 000 000 000
192 198 204 210 216 222 229 235 242 248
40 42 44 46 48 50 52 54 56 58
5 6 6 7 7 8 9 9 10 11
780 240 740 280 850 460 110 800 500 300
3.34 3.54 3.74 3.96 4.18 4.42 4.66 4.92 5.19 5.48
150 152 154 156 158 160 162 164 166 168
177 186 195 205 215 225 236 248 259 272
000 000 000 000 000 000 000 000 000 000
43.2 44.9 46.6 48.4 50.2 52.1 54.1 56.1 58.2 60.3
260 280 300 320 340 360 380 400 420 440
1 2 3 4 5 7 9 11 14 18
680 340 180 260 610 270 300 700 700 100
000 000 000 000 000 000 000 000 000 000
255 333 430 548 692 869 1090 1360 1700 2130
60 62 64 66 68
12 13 14 15 16
200 100 000 000 100
5.77 6.08 6.41 6.74 7.10
170 172 174 176 178
285 298 312 326 341
000 000 000 000 000
62.5 64.8 67.1 69.5 72.0
460
22 200 000
NOTE 1—To correct A and B to other base conditions, multiply each by: ~Pb/14.7! 3 @519.6/~tb 1 459.6!# 3 ~0.998/Zb!
where: Pb = absolute base pressure, psia; tb = base temperature, °F; and Zb = compressibility factor under base conditions.
6
D 1142 – 95 (2000) TABLE 3 Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (lb/million ft3 where Pb = 14.7 psia, tb = 60°F) Temperature,
Total Pressure, psia
°F
14.7
100
200
300
400
500
600
700
800
900
1000
−40 −38 −36 −34 −32
9.1 10.2 11.5 12.8 14.4
1.5 1.7 1.9 2.1 2.4
0.88 0.98 1.1 1.2 1.3
0.66 0.73 0.80 0.90 0.99
0.55 0.61 0.68 0.74 0.82
0.49 0.54 0.59 0.65 0.72
0.44 0.49 0.54 0.59 0.65
0.41 0.45 0.50 0.55 0.60
0.39 0.43 0.47 0.51 0.57
0.37 0.41 0.45 0.49 0.54
0.36 0.39 0.43 0.47 0.51
−30 −28 −26 −24 −22
16.0 17.8 19.8 22.0 24.4
2.6 2.9 3.2 3.6 4.0
1.5 1.6 1.8 2.0 2.2
1.1 1.2 1.3 1.5 1.6
0.91 1.0 1.1 1.2 1.3
0.79 0.87 0.96 1.1 1.2
0.72 0.79 0.86 0.95 1.0
0.66 0.72 0.79 0.87 0.95
0.62 0.68 0.74 0.81 0.89
0.59 0.64 0.70 0.77 0.84
0.56 0.61 0.67 0.73 0.80
−20 −18 −16 −14 −12
27.0 30.0 33.1 36.7 40.5
4.4 4.9 5.4 5.9 6.5
2.4 2.7 3.0 3.3 3.6
1.8 2.0 2.2 2.4 2.6
1.5 1.6 1.8 1.9 2.1
1.3 1.4 1.5 1.7 1.8
1.1 1.2 1.4 1.5 1.6
1.0 1.1 1.2 1.4 1.5
0.97 1.1 1.2 1.3 1.4
0.92 1.0 1.1 1.2 1.3
0.87 0.95 1.0 1.1 1.2
−10 −8 −6 −4 −2
44.8 49.3 54.6 59.8 65.7
7.2 7.9 8.7 9.5 10.4
4.0 4.3 4.7 5.2 5.7
2.9 3.1 3.4 3.7 4.1
2.3 2.5 2.8 3.0 3.3
2.0 2.2 2.4 2.6 2.8
1.8 1.9 2.1 2.3 2.5
1.6 1.8 1.9 2.1 2.3
1.5 1.6 1.8 1.9 2.1
1.4 1.5 1.7 1.8 2.0
1.3 1.5 1.6 1.7 1.9
0 2 4 6 8
72.1 79.1 86.8 95.1 104
11.4 12.5 13.7 15.0 16.4
6.2 6.8 7.4 8.1 8.8
4.5 4.9 5.3 5.8 6.3
3.6 3.9 4.3 4.6 5.1
3.1 3.3 3.6 4.0 4.3
2.7 3.0 3.2 3.5 3.8
2.5 2.7 2.9 3.2 3.4
2.3 2.5 2.7 2.9 3.2
2.1 2.3 2.5 2.7 3.0
2.0 2.2 2.4 2.6 2.8
10 12 14 16 18
114 124 136 148 161
17.9 19.5 21.3 23.2 25.2
9.6 10.5 11.4 12.4 13.5
6.9 7.5 8.1 8.8 9.6
5.5 6.0 6.5 7.0 7.6
4.7 5.1 5.5 5.9 6.4
4.1 4.5 4.8 5.2 5.7
3.7 4.0 4.5 4.7 5.1
3.4 3.7 4.0 4.3 4.7
3.2 3.5 3.7 4.0 4.4
3.0 3.3 3.5 3.8 4.1
20 22 24 26 28
176 191 208 226 246
27.4 29.8 32.4 35.1 38.1
14.6 15.9 17.2 18.7 20.2
10.4 11.3 12.2 13.2 14.3
8.2 8.9 9.7 10.5 11.3
7.0 7.5 8.2 8.8 9.5
6.1 6.6 7.2 7.7 8.3
5.5 5.9 6.4 6.9 7.5
5.1 5.5 5.9 6.3 6.8
4.7 5.1 5.5 5.9 6.3
4.4 4.8 5.1 5.5 5.9
30 32 34 36 38
276 289 313 339 367
41.3 44.7 48.4 52.4 56.6
21.9 23.7 25.6 27.7 29.9
15.4 16.7 18.0 19.4 20.1
12.2 13.2 14.2 15.3 16.5
10.3 11.1 11.9 12.9 13.9
9.0 9.7 10.4 11.2 12.1
8.0 8.7 9.3 10.0 10.8
7.4 7.9 8.5 9.2 9.8
6.8 7.3 7.9 8.5 9.1
6.4 6.9 7.4 7.9 8.5
40 42 44 46 48 50 52 54 56 58
396 428 462 499 538 80 624 672 721 776
61.1 66.0 71.2 76.7 82.6 89.0 95.7 103 111 119
32.2 34.8 37.5 40.3 43.4 46.7 50.2 54.0 57.9 62.1
22.6 24.4 26.2 28.2 30.3 32.6 35.0 37.6 40.3 43.2
17.8 19.2 20.6 22.2 23.8 25.6 27.4 29.4 31.5 33.8
14.9 16.0 17.2 18.5 19.9 21.3 22.9 24.5 26.7 28.1
13.0 13.9 15.0 16.1 17.3 18.5 19.8 21.3 22.8 24.4
11.6 12.5 13.4 14.4 15.4 16.5 17.7 18.9 20.3 21.7
10.6 11.3 12.2 13.1 14.0 15.0 16.1 17.2 18.3 19.6
9.8 10.5 11.2 12.0 12.9 13.8 14.8 15.8 16.9 18.0
9.1 9.8 10.5 11.2 12.0 12.9 13.8 14.7 15.7 16.8
60 62 64 66 68
834 895 960 1030 1100
128 137 147 157 168
66.6 71.4 76.5 81.8 87.6
46.3 49.6 53.1 56.8 60.7
36.2 38.7 41.4 44.3 47.3
30.1 32.2 34.4 36.8 39.3
26.1 27.9 29.8 31.8 33.9
23.2 24.7 26.4 28.2 30.1
21.0 22.4 23.9 25.5 27.2
19.3 20.6 22.0 23.4 25.0
17.9 19.1 20.4 21.8 23.2
70 72 74 76 78 80
1180 1260 1350 1440 1540 1650
180 192 206 220 235 250
93.7 100 107 114 122 130
65.0 69.4 74.0 79.0 84.2 89.8
50.6 54.0 57.6 61.4 65.5 69.7
42.0 44.8 47.7 50.9 54.2 57.5
36.2 38.6 41.1 43.8 46.7 49.7
32.1 34.2 36.4 38.8 41.3 44.0
29.0 30.9 32.9 35.0 37.3 39.7
26.6 28.4 30.2 32.1 34.2 36.3
24.7 26.3 28.0 29.8 31.7 33.6
7
D 1142 – 95 (2000) TABLE 3 Continued Temperature,
Total Pressure, psia
°F
14.7
100
200
300
400
500
600
700
800
900
1000
82 84 86 88
1760 1870 2000 2130
267 285 303 323
138 148 157 167
95.6 102 108 115
74.2 79.0 84.1 89.4
61.4 65.3 69.5 73.8
52.8 56.2 59.7 63.5
46.7 49.7 52.8 56.1
42.1 44.8 47.6 50.5
38.6 41.0 43.5 46.2
36.7 37.9 40.3 42.7
90 92 94 96 98
2270 2410 2570 2730 2900
344 366 389 413 439
178 189 201 214 227
123 130 138 147 156
95.0 101 107 114 121
78.5 83.3 88.4 93.8 99.5
67.4 71.5 75.9 80.5 85.3
59.5 63.1 67.0 71.0 75.2
53.6 56.8 60.3 63.9 67.6
49.0 51.9 55.0 58.3 61.8
45.3 48.0 50.9 53.9 57.0
100 102 104 106 108
3080 3270 3470 3680 3900
466 495 525 557 589
241 256 271 287 304
166 176 186 197 209
128 136 144 152 161
105 112 118 125 133
90.4 95.8 101 107 114
79.7 84.4 89.3 94.5 99.9
71.6 75.9 80.2 84.9 89.7
65.4 69.2 73.1 77.4 81.7
... ... ... ... ...
110 112 114 116 118
4130 4380 4640 4910 5190
624 661 700 740 783
322 341 360 381 403
221 234 247 261 276
170 180 191 201 213
140 148 157 165 175
120 127 134 142 149
106 112 118 124 131
94.7 100 106 112 118
86.3 91.2 96.2 102 107
... ... ... ... ...
120 122 124 126 128
5490 5800 6130 6470 6830
828 874 923 974 1030
426 449 474 500 528
292 308 325 343 361
225 237 250 264 278
185 195 205 216 228
158 166 175 185 195
139 146 154 162 171
124 131 138 145 153
113 119 125 132 139
... ... ... ... ...
130 132 134 136 138
7240 7580 7990 8470 8880
1090 1140 1200 1270 1330
559 585 617 653 684
382 400 422 446 468
294 308 324 343 359
241 252 266 281 294
206 215 227 240 251
181 189 199 210 220
162 169 178 188 197
147 154 162 171 179
... ... ... ... ...
140 142 144 146 148
9360 9830 10 400 10 900 11 500
1410 1480 1560 1640 1720
721 757 799 840 882
492 517 545 573 602
378 397 419 440 462
310 325 343 360 378
264 277 292 307 322
231 243 256 269 282
207 217 229 240 252
188 197 207 218 229
... ... ... ... ...
8
D 1142 – 95 (2000) TABLE 4 Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (lb/million ft3 where Pb = 14.7 psia, tb = 60°F) Temperature, °F
Total Pressure, psia 100
200
300
400
500
600
700
800
900
150 152 154 156 158
12 12 13 14 14
14.7 100 700 300 000 700
1810 1910 2000 2100 2200
928 975 1020 1070 1130
633 665 697 732 767
486 510 534 561 588
397 417 437 458 480
338 355 372 390 409
296 311 325 341 357
264 277 290 305 319
240 252 263 276 289
160 162 164 166 168
15 400 ... ... ... ...
2300 2410 2540 2650 2780
1180 1230 1300 1350 1420
802 841 883 922 967
615 644 676 706 740
502 526 552 576 604
427 447 469 490 514
374 391 410 428 449
333 349 366 382 400
302 316 332 346 363
170 172 174 176 178
... ... ... ... ...
2910 3040 3190 3330 3480
1490 1550 1630 1700 1780
1010 1060 1110 1160 1210
775 810 847 885 925
633 661 691 722 754
538 562 587 613 640
470 491 513 535 559
419 437 457 477 498
379 396 414 432 451
180 182 184 186 188
... ... ... ... ...
3640 3800 3980 4150 4340
1860 1940 2030 2120 2210
1260 1320 1380 1440 1500
967 1010 1060 1100 1150
789 821 860 897 936
670 697 730 761 794
585 609 637 664 693
521 542 567 591 617
471 491 513 535 558
190 192 194 196 198
... ... ... ... ...
4520 4720 4920 5140 5350
2300 2410 2510 2620 2730
1570 1630 1700 1780 1850
1200 1250 1300 1360 1410
974 1020 1060 1110 1150
827 863 900 938 976
721 753 785 818 851
642 670 698 728 757
581 606 631 658 684
200 202 204 206 208
... ... ... ... ...
5570 5810 6050 6310 ...
2840 2960 3080 3210 3340
1930 2010 2090 2180 2270
1470 1530 1600 1660 1730
1200 1250 1300 1350 1400
1020 1060 1100 1150 1190
885 922 960 999 1040
788 821 854 889 924
712 741 771 803 835
210 212 214 216 218
... ... ... ... ...
... ... ... ... ...
3480 3620 3760 3910 4060
2360 2450 2550 2650 2760
1800 1870 1950 2020 2100
1460 1520 1580 1640 1710
1240 1290 1340 1390 1450
1080 1120 1160 1210 1260
961 999 1040 1080 1120
868 902 937 973 1010
220 222 224 226 228
... ... ... ... ...
... ... ... ... ...
4220 4390 4560 4730 4910
2860 2980 3090 3200 3330
2180 2270 2350 2440 2540
1780 1840 1910 1990 2060
1500 1560 1620 1680 1750
1310 1360 1410 1460 1520
1160 1200 1250 1300 1350
1050 1090 1130 1170 1220
230
...
...
5100
3460
2630
2140
1810
1580
1400
1260
240
...
...
...
4160
3170
2570
2180
1890
1680
1510
250
...
...
...
...
3770
3060
2590
2250
2000
1800
9
D 1142 – 95 (2000) TABLE 5 Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (lb/million ft3 where Pb = 14.7 psia, tb = 60°F) Total Pressure, psia
Temperature, °F
1000
1500
2000
2500
3000
3500
4000
4500
5000
100 102 104 106 108
60.4 63.9 67.5 71.4 75.4
45.4 47.9 50.6 53.4 56.4
37.9 40.0 42.1 44.5 46.9
33.3 35.5 37.0 39.1 41.1
30.3 32.0 33.6 35.5 37.3
28.2 29.7 31.2 32.9 34.6
26.6 28.0 29.4 31.0 32.6
25.3 26.6 28.0 29.5 31.0
24.3 25.6 26.9 28.3 29.7
110 112 114 116 118
79.6 84.1 88.7 93.6 98.7
59.4 62.7 66.1 69.7 73.4
49.4 52.1 54.8 57.7 60.7
43.3 45.6 48.0 50.5 53.1
39.3 41.4 43.4 45.7 48.0
36.4 38.3 40.2 42.3 44.4
34.2 36.0 37.8 39.8 41.7
32.5 34.2 35.9 37.8 39.6
31.2 32.8 34.4 36.2 37.9
120 122 124 126 128
104 110 116 122 128
77.3 81.3 85.6 89.9 94.7
63.9 67.2 70.7 74.2 78.0
55.9 58.7 61.7 64.7 68.0
50.5 53.0 55.7 58.4 61.3
46.7 49.0 51.4 53.9 56.6
43.8 45.9 48.2 50.5 53.0
41.6 43.6 45.7 47.8 50.2
39.8 41.7 43.7 45.7 48.0
130 132 134 136 138
135 141 149 157 164
99.8 104 110 116 121
82.1 85.8 90.1 94.9 99.2
71.5 74.7 78.4 82.5 86.2
64.4 67.3 70.6 74.2 77.5
59.4 62.0 65.0 68.3 71.3
55.6 58.1 60.9 63.9 66.7
52.6 55.0 57.6 60.3 63.1
50.3 52.5 55.0 57.7 60.2
140 142 144 146 148
173 181 191 200 210
127 133 140 147 154
104 109 115 120 126
90.4 94.6 99.3 104 109
81.3 85.0 89.2 93.0 97.6
74.7 78.1 81.9 85.7 89.6
69.9 73.0 76.5 80.0 83.6
66.0 69.0 72.3 75.6 78.9
63.0 65.8 68.9 72.0 75.6
150 152 154 156 158
220 231 242 253 265
161 169 177 185 194
132 138 144 151 158
114 119 125 130 136
102 107 112 117 122
93.8 98.0 102 107 112
87.5 91.4 95.4 100 104
82.5 86.2 89.9 94.0 98.0
78.6 82.1 85.6 89.4 93.2
160 162 164 166 168
277 290 304 317 332
202 211 221 231 242
165 172 180 188 196
142 149 155 162 169
127 133 139 145 151
116 122 127 132 138
108 113 118 123 128
102 107 111 116 121
97.1 101 106 110 115
170 172 174 176 178
348 363 379 396 413
253 263 275 287 299
205 214 223 233 243
177 184 192 200 208
158 165 171 178 186
144 150 156 163 169
134 139 145 151 157
126 131 136 142 148
120 124 130 135 140
180 182 184 186 188
432 449 470 490 511
313 325 340 354 369
253 263 275 286 298
217 226 236 245 256
194 201 210 218 227
177 184 191 199 207
164 170 177 184 192
154 160 167 173 180
146 152 158 164 171
190 192 194 196 198 200 202 204 206 208
531 554 578 602 626 651 678 705 734 763
384 400 417 434 451 469 488 507 528 548
310 323 336 350 364 378 393 408 425 441
266 277 288 299 311 323 336 349 363 377
236 246 256 266 276 286 298 309 321 334
215 224 233 242 251 260 271 281 292 303
199 207 215 224 232 241 251 260 270 280
187 194 202 210 218 226 235 243 253 262
177 184 191 199 206 213 222 230 238 248
210 212 214 216 218
793 824 856 889 924
569 591 614 637 662
458 475 493 512 532
390 405 420 436 453
346 359 372 386 401
314 325 337 350 363
290 301 312 323 335
271 281 291 302 313
256 266 275 285 296
10
D 1142 – 95 (2000) TABLE 5 Continued Temperature, °F
Total Pressure, psia 3500
4000
220 222 224 226 228
959 996 1030 1070 1110
1000
687 713 739 767 795
1500
551 572 593 615 637
2000
469 487 504 523 542
2500
415 431 446 462 479
3000
376 390 404 418 433
347 360 372 386 400
324 336 348 360 373
4500
306 318 328 340 352
230
1150
824
660
561
495
448
413
385
363
240
1380
985
787
668
589
532
490
456
430
250
1640
1170
932
790
695
628
577
538
506
ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years and if not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below. This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at 610-832-9585 (phone), 610-832-9555 (fax), or [email protected] (e-mail); or through the ASTM website (www.astm.org).
11
5000
Standard Test Method for
Water Vapor Content of Gaseous Fuels by Measurement of Dew-Point Temperature1 This standard is issued under the fixed designation D 1142; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the Department of Defense.
2.1.1 saturated water vapor or equilibrium water–vapor content—the water vapor concentration in a gas mixture that is in equilibrium with a liquid phase of pure water that is saturated with the gas mixture. When a gas containing water vapor is at the water dew-point temperature, it is said to be saturated at the existing pressure. 2.1.2 specific volume—of a gaseous fuel, the volume of the gas in cubic feet per pound. 2.1.3 water dew-point temperature—of a gaseous fuel, the temperature at which the gas is saturated with water vapor at the existing pressure.
1. Scope 1.1 This test method covers the determination of the water vapor content of gaseous fuels by measurement of the dewpoint temperature and the calculation therefrom of the water vapor content. NOTE 1—Some gaseous fuels contain vapors of hydrocarbons or other components that easily condense into liquid and sometimes interfere with or mask the water dew point. When this occurs, it is sometimes very helpful to supplement the apparatus in Fig. 1 with an optical attachment2 that uniformly illuminates the dew–point mirror and also magnifies the condensate on the mirror. With this attachment it is possible, in some cases, to observe separate condensation points of water vapor, hydrocarbons, and glycolamines as well as ice points. However, if the dew point of the condensable hydrocarbons is higher than the water vapor dew point, when such hydrocarbons are present in large amounts, they may flood the mirror and obscure or wash off the water dew point. Best results in distinguishing multiple component dew points are obtained when they are not too closely spaced. NOTE 2—Condensation of water vapor on the dew-point mirror may appear as liquid water at temperatures as low as 0 to −10°F (−18 to −23°C). At lower temperatures an ice point rather than a water dew point likely will be observed. The minimum dew point of any vapor that can be observed is limited by the mechanical parts of the equipment. Mirror temperatures as low as −150°F (−100°C) have been measured, using liquid nitrogen as the coolant with a thermocouple attached to the mirror, instead of a thermometer well.
3. Significance and Use 3.1 Generally, contracts governing the pipeline transmission of natural gas contain specifications limiting the maximum concentration of water vapor allowed. Excess water vapor can cause corrosive conditions, degrading pipelines and equipment. It can also condense and freeze or form methane hydrates causing blockages. Water–vapor content also affects the heating value of natural gas, thus influencing the quality of the gas. This test method permits the determination of water content of natural gas. 4. Apparatus 4.1 Any properly constructed dew-point apparatus may be used that satisfies the basic requirements that means must be provided: 4.1.1 To permit a controlled flow of gas to enter and leave the apparatus while the apparatus is at a temperature at least 3°F above the dew point of the gas. 4.1.2 To cool and control the cooling rate of a portion (preferably a small portion) of the apparatus, with which the flowing gas comes in contact, to a temperature low enough to cause vapor to condense from the gas. 4.1.3 To observe the deposition of dew on the cold portion of the apparatus. 4.1.4 To measure the temperature of the cold portion on the apparatus on which the dew is deposited, and
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Terminology 2.1 Definitions of Terms Specific to This Standard: 1 This test method is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.05 on Determination of Special Constituents of Gaseous Fuels. Current edition approved Feb. 15, 1995. Published April 1995. Originally published as D 1142 – 50. Last previous edition D 1142 – 90. 2 Several pieces of apparatus for this purpose are commercially available. Information concerning this apparatus is available from ASTM Headquarters.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
D 1142 – 95 (2000)
FIG. 1 Bureau of Mines Dew-Point Apparatus
refrigerant such as liquid butane, propane, carbon dioxide, or some other liquefied gas in the chiller, G. The refrigerant is throttled into the chiller through valve H and passes out at J. The chiller body is made of copper and has brass headers on either end. The lower header is connected with the upper header by numerous small holes drilled in the copper body through which the vaporized refrigerant passes. The chiller is attached to the cooling rod, F, by means of a taper joint. The temperature of the target mirror, C, is indicated by a calibrated mercury-in-glass thermometer, K, whose bulb fits snugly into the thermometer well. Observation of the dew deposit is made through the pressure-resisting transparent window, E. 4.2.1 Note that only the central portion of the stainless steel target mirror, C, is thermally bonded to the fitting, I, through which C is cooled. Since stainless steel is a relatively poor thermal conductor, the central portion of the mirror is thus maintained at a slightly lower temperature than the outer portion, with the result that the dew first appears on the central portion of the mirror and its detection is aided materially by the contrast afforded. The arrangement for measuring the temperature of the target mirror, C, also should be noted. The temperature is read with a thermometer or RTD, K, inserted in the cooling rod, F, so that the bulb of the temperature measuring device is entirely within the thermometer well in fitting, I. The stud to which the stainless steel mirror is silver-soldered is a part of the base of the thermometer well, and as there is no metallic contact between the thermometer
4.1.5 To measure the pressure of the gas within the apparatus or the deviation from the known existing barometric pressure. 4.1.6 The apparatus should be constructed so that the “cold spot,” that is, the cold portion of the apparatus on which dew is deposited, is protected from all gases other than the gas under test. The apparatus may or may not be designed for use under pressure. 4.2 The Bureau of Mines type of dew-point apparatus3 shown in Fig. 1 fulfills the requirements specified in 4.1. Within the range of conditions in Section 1, this apparatus is satisfactory for determining the dew point of gaseous fuels. Briefly, this apparatus consists of a metal chamber into and out of which the test gas is permitted to flow through control valves A and D. Gas entering the apparatus through valve A is deflected by nozzle B towards the cold portion of the apparatus, C. The gas flows across the face of C and out of the apparatus through valve D. Part C is a highly polished stainless steel “target mirror,” cooled by means of a copper cooling rod, F. The mirror, C, is silver-soldered to a nib on the copper thermometer well fitting, I, which is soft-soldered to the cooling rod, F. The thermometer well is integral with the fitting, I. Cooling of rod F is accomplished by vaporizing a
3 Deaton, W. M., and Frost, E. M., Jr., “Bureau of Mines Apparatus for Determining the Dew Point of Gases Under Pressure,” Bureau of Mines Report of Investigation 3399, May 1938.
2
D 1142 – 95 (2000) conditions as nearly as possible. The most satisfactory method is to cool or warm the target mirror stepwise. Steps of about 0.2°F (0.1°C) allow equilibrium conditions to be approached closely and favor an accurate determination. When dew has been deposited, allow the target mirror to warm up at a rate comparable to the recommended rate of cooling. The normal warming rate usually will be faster than desired. To reduce the rate, “crack” valve H momentarily at intervals to supply cooling to the cooling tube, F. Repeat the cooling and warming cycles several times. The arithmetic average of the temperatures at which dew is observed to appear and disappear is considered to be the observed dew point.
well and the cooling tube, other than through its base, the thermometer or RTD indicates the temperature of the mirror rather than some compromise temperature influenced by the temperature gradient along the cooling tube as would be the case if this type of construction were not used. The RTD will include suitable electronics and display. 4.2.2 Tests with the Bureau of Mines type of dew-point apparatus are reported3 to permit a determination with a precision (reproducibility) of 60.2°F (60.1°C) and with an accuracy of 60.2°F (60.1°C) when the dew-point temperatures range from room temperature to a temperature of 32°F (0°C). It is estimated that water dew points may be determined with an accuracy of 60.5°F (0.3°C) when they are below 32°F (0°C) and not lower than 0°F (−17.8°C), provided ice crystals do not form during the determination.
NOTE 3—If the water–vapor content is to be calculated as described in 6.2, the gas specimen should be throttled at the inlet valve, A, to a pressure within the apparatus approximately equal to atmospheric pressure. The outlet valve may be left wide open or restricted, as desired. The pressure existing within the apparatus must, however, be known to the required accuracy.
5. Procedure 5.1 General Considerations—Take the specimen so as to be representative of the gas at the source. Do not take at a point where isolation would permit condensate to collect or would otherwise allow a vapor content to exist that is not in equilibrium with the main stream or supply of gas, such as the sorption or desorption of vapors from the sampling line or from deposits therein. The temperature of the pipelines leading the specimen directly from the gas source to the dew-point apparatus, and also the temperature of the apparatus, shall be at least 3°F (1.7°C) higher than the observed dew point. The determination may be made at any pressure, but the gas pressure within the dew-point apparatus must be known with an accuracy appropriate to the accuracy requirements of the test. The pressure may be read on a calibrated bourdon-type pressure gage; for very low pressures or more accurate measurements, a mercury-filled manometer or a dead-weight gage should be used. 5.2 Detailed Procedure for Operation of Bureau of Mines Dew-Point Apparatus—Introduce the gas specimen through valve A (Fig. 1), opening this valve wide if the test is to be made under full source pressure (Note 3), and controlling the flow by the small outlet valve, D. The rate of flow is not critical but should not be so great that there is a measurable or objectionable drop in pressure through the connecting lines and dew-point apparatus. A flow of 0.05 to 0.5 ft3/min (1.4 to 14 L/min) (measured at atmospheric pressure) usually will be satisfactory. With liquefied refrigerant gas piped to the chiller throttle valve, H, “crack” the valve momentarily, allowing the refrigerant to vaporize in the chiller to produce suitable lowering in temperature of the chiller tube, F, and target mirror, C, as indicated by the thermometer, K. The rate of cooling may be as rapid as desired in making a preliminary test. After estimating the dew-point temperature, either by a preliminary test or from other knowledge, control the cooling or warming rate so that it does not exceed 1°F/min (0.5°C/min) when this temperature is approached. For accurate results, the cooling and warming rates should approximate isothermal
6. Calculation 6.1 If an acceptable chart showing the variation of watervapor content with saturation or water dew-point temperatures over a suitable range of pressures for the gas being tested is available, the water-vapor content may be read directly, using the observed water dew-point temperature and the pressure at which the determination was made. 6.2 If such a chart is not available, the water–vapor content of the gas may be calculated from the water dew-point temperature and the pressure at which it was determined (see Note 3), as follows:
FIG. 2 Equilibrium Water Vapor Content of Natural Gases
3
D 1142 – 95 (2000) W 5 w 3 10 6 3 ~Pb/P 3 ~T/T b!!
6.3 A correlation of the available data on the equilibrium water content of natural gases has been reported by Bukacek.5 This correlation is believed to be accurate enough for the requirements of the gaseous fuels industry, except for unusual situations where the dew point is measured at conditions close to the critical temperature of the gas. The correlation is a modified form of Raoult’s law having the following form:
(1)
where: W = lb of water/million ft3 of gaseous mixture at pressure Pb and temperature Tb; w = weight of saturated water vapor, lb/ft3, at the water dew-point temperature, that is, the reciprocal of the specific volume of saturated vapor (see Table 1); Pb = pressure-base of gas measurement, psia; P = pressure at which the water dew point of gas was determined, psia; t = observed water dew-point temperature, °F; T = Rankine (absolute Fahrenheit scale) water dew point, t + 460, at pressure P; and Tb = base temperature of gas measurement, tb + 460.
W 5 ~A/P! 1 B
(2)
where: W = water–vapor content, lb/million ft3; P = total pressure, psia; A = a constant proportional to the vapor pressure of water; and B = a constant depending on temperature and gas composition.
NOTE 4—Example 1: Given: Water dew point = 37°F at 15.0-psia pressure. What is the water–vapor content million ft3 of gas (gas measurement base of 60°F and 14.7-psia pressure)? From Table 1 the specific volume of saturated water at 37°F is 2731.9 ft3/lb, from which: w = (1/2731.9) = 0.000 366 0 lb/ft3 and W = 0.000 366 0 3 10 6 3 (14.7/15.0) 3 [(460 + 37)/(460 + 60)] = 342.8 lb/million ft3 Example 2: Given: Water dew point = 5°F at 14.4 psia. From Table 2, the specific volume of saturated water vapor with respect to ice at 5°F is 11 550 ft3/lb from which Wice, 5F = 0.000 086 6, but the observed water dew point was in equilibrium with subcooled liquid water at 5°F. From Table 2 (data from International Critical Tables4), the vapor pressures of subcooled liquid water and of ice at 5°F (−15°C) are 1.436 mm and 1.241 mm Hg, respectively. Since the vapor pressure of subcooled liquid water is greater than ice at the same temperature, the weight per cubic foot of water vapor in equilibrium with liquid water will be proportionately larger than the value calculated from the specific volume read from the table, which is for equilibrium with ice. Hence, Wliq., 5F = W ice 5F3 (1.436/1.241) = 0.000 086 6 3 1.157 = 0.000 100 2 and W = 0.000 100 2 3 10 6 3 (14.7/14.4) 3 [(460 + 5)/[460 + 60)] = 91.5 lb/million ft3
NOTE 5—Values of B were computed from available data on methane, methane-ethane mixtures, and natural gases.
6.3.1 Table 2 lists values of the constants A and B for natural gases in the temperature range from −40 to 460°F (−40 to 238°C). 6.3.2 Tables 3-5 list values of water–vapor content from −40 to 250°F (−40° to 121°C) and from 14.7 to 5000 psia (101 to 34 475 kPa), covering the range of most natural gas processing applications. 6.3.3 A convenient graphical representation of the data in Tables 3-5 is illustrated in Fig. 2.6 The moisture content values given can be corrected to base conditions other than 14.7 psia (101 kPa) and 60°F (15.5°C) by the same equations given in Table 2. 7. Precision and Bias 7.1 No precision data is available for this test method, however, the Committee is interested in conducting an interlaboratory test program and encourages interested parties to contact the Staff Manager, Committee D03, ASTM Headquarters. 8. Keywords 8.1 gaseous fuels; natural gas 5 Bukacek, R. F., “Equilibrium Moisture Content of Natural Gases,” Research Bulletin 8, Institute of Gas Technology, 1955. Reports work sponsored by the Pipeline Research Committee of the American Gas Association. 6 Complete sets of these charts covering the entire range of pressures and temperatures of Tables 3-5 may be purchased from the Institute of Gas Technology, 1700 S. Mount Prospect Rd., Des Plaines, IL 60018.
4 International Critical Tables, Vol III, National Research Council, McGraw-Hill Book Co., Inc., New York, 1928, pp. 210–211.
4
D 1142 – 95 (2000) TABLE 1 Vapor Pressures and Specific Volumes of Saturated Water Vapor at Various TemperaturesA Vapor Pressure of Liquid Water
Specific Volume of Saturated Water Vapor ft3/lb
Vapor Pressure of Ice
Temperature, °F
Temperature, °F
Vapor Pressure of Liquid Water, psia
Specific Volume of Saturated Water Vapor, ft3/lb
mm Hg
psia
mm Hg
psia
0
1.139
0.022 02
0.958
0.018 52
14 810
1 2 3 4 5
1.195 1.251 1.310 1.373 1.436
0.023 0.024 0.025 0.026 0.027
11 19 33 55 77
1.010 1.063 1.120 1.180 1.241
0.019 0.020 0.021 0.022 0.024
53 56 66 82 00
14 13 12 12 11
080 400 750 140 550
51 52 53 54 55
0.184 0.191 0.199 0.206 0.214
85 82 01 44 11
1 1 1 1 1
644.2 587.6 533.2 480.9 430.6
6 7 8 9 10
1.505 1.573 1.647 1.723 1.807
0.029 0.030 0.031 0.033 0.034
10 42 85 32 94
1.308 1.374 1.446 1.521 1.599
0.025 0.026 0.027 0.029 0.030
29 57 96 41 92
11 10 9 9 9
000 480 979 507 060
56 57 58 59 60
0.222 0.230 0.238 0.247 0.256
03 21 65 36 35
1 1 1 1 1
382.2 335.6 290.9 247.8 206.3
11 12 13 14 15
1.883 1.970 2.057 2.149 2.247
0.036 0.038 0.039 0.041 0.043
41 09 78 56 45
1.681 1.767 1.856 1.950 2.050
0.032 0.034 0.035 0.037 0.039
51 17 89 71 64
8 8 7 7 7
636 234 851 489 144
61 62 63 64 65
0.265 0.275 0.285 0.295 0.305
62 19 06 24 73
1 1 1 1 1
166.4 128.0 091.0 055.4 021.1
16 17 18 19 20
2.345 2.450 2.557 2.607 2.785
0.045 0.047 0.049 0.051 0.053
35 37 44 63 85
2.151 2.260 2.373 2.489 2.610
0.041 0.043 0.045 0.048 0.050
59 70 89 13 47
6 6 6 5 5
817 505 210 929 662
66 67 68 69 70
0.316 0.327 0.339 0.351 0.363
55 70 20 05 26
988.03 956.19 925.51 895.94 867.44
21 22 23 24 25
2.907 3.032 3.163 3.299 3.433
0.056 0.058 0.061 0.063 0.066
21 63 16 79 38
2.740 2.872 3.013 3.160 3.310
0.052 0.055 0.058 0.061 0.064
98 54 26 10 01
5 5 4 4 4
408 166 936 717 509
71 72 73 74 75
0.375 0.388 0.402 0.415 0.430
84 79 14 88 04
839.97 813.48 787.94 763.31 739.55
26 27 28 29 30
3.585 3.735 3.893 4.054 4.224
0.069 0.072 0.075 0.078 0.081
32 22 28 39 68
3.471 3.636 3.810 3.989 4.178
0.067 0.070 0.073 0.077 0.080
12 31 67 14 79
4 4 3 3 3
311 122 943 771 608
76 77 78 79 80
0.444 0.459 0.475 0.490 0.507
61 61 05 94 29
716.62 694.51 673.16 652.56 632.68
31 32 33 34 35
4.397 4.579 ... ... ...
0.085 0.088 0.092 0.096 0.099
02 66 30 07 98
4.373 4.579 ... ... ...
0.084 56 0.088 54 ... ... ...
3 3 3 3 2
453 301.9 178.0 059.2 945.5
81 82 83 84 85
0.524 0.541 0.559 0.577 0.596
11 42 22 53 36
613.48 594.95 577.05 559.76 543.07
36 37 38 39 40
... ... ... ... ...
0.104 0.108 0.112 0.117 0.121
04 23 58 08 73
... ... ... ... ...
... ... ... ... ...
2 2 2 2 2
836.4 731.9 631.7 535.7 443.5
86 87 88 89 90
0.615 0.635 0.656 0.677 0.698
73 63 09 13 74
526.94 511.35 496.29 481.73 467.66
41 42 43 44 45
... ... ... ... ...
0.126 0.131 0.136 0.142 0.147
55 54 70 04 56
... ... ... ... ...
... ... ... ... ...
2 2 2 2 2
355.1 270.3 188.9 110.8 035.8
91 92 93 94 95
0.720 0.743 0.767 0.791 0.816
95 77 22 30 04
454.06 440.91 428.19 415.89 403.99
46 47 48 49 50
... ... ... ... ...
0.153 0.159 0.165 0.171 0.178
28 18 28 59 12
... ... ... ... ...
... ... ... ... ...
1 1 1 1 1
963.8 894.6 828.2 764.4 703.1
96 97 98 99 100
0.841 0.867 0.894 0.921 0.950
44 53 31 80 03
392.48 381.35 370.58 360.15 350.06
A The values for vapor pressure, from 0 to 32°F, were calculated from data in the International Critical Tables.4 All other values were taken from Harr, Gallagher, and Kell, “NBS/NRC Steam Tables,” National Standard Reference Data System, 1984, p. 9. Data on specific volumes of saturated water vapor from 0 to 32°F were obtained from Goff, J. A., and Gratch, S., “ Low-Pressure Properties of Water from −160 to 212°F,” Heating, Piping, and Air Conditioning, Vol 18, No. 2, Feb. 1946, pp. 125–136.
5
D 1142 – 95 (2000) TABLE 2 Values of Constants A and B (Base Conditions = 14.7 psia, 60°F) Temperature, °F
A
B
Temperature, °F
A
B
Temperature, °F
A
B
−40 −38 −36 −34 −32 −30 −28 −26 −24 −22
131 147 165 184 206 230 256 285 317 352
0.22 0.24 0.26 0.28 0.30 0.33 0.36 0.39 0.42 0.45
70 72 74 76 78 80 82 84 86 88
17 18 19 21 22 24 25 27 29 31
200 500 700 100 500 100 700 400 200 100
7.17 7.85 8.25 8.67 9.11 9.57 10.0 10.5 11.1 11.6
180 182 184 186 188 190 192 194 196 198
357 372 390 407 425 443 463 483 504 525
000 000 000 000 000 000 000 000 000 000
74.8 77.2 79.9 82.7 85.8 88.4 91.4 94.8 97.7 101
−20 −18 −16 −14 −12 −10 −8 −6 −4 −2
390 434 479 530 586 648 714 786 866 950
0.48 0.52 0.56 0.60 0.64 0.69 0.74 0.79 0.85 0.91
90 92 94 96 98 100 102 104 106 108
33 35 37 39 42 45 47 50 53 57
200 300 500 900 400 100 900 800 900 100
12.2 12.7 13.3 14.0 14.6 15.3 16.0 16.7 17.5 18.3
200 202 204 206 208 210 212 214 216 218
547 570 594 619 644 671 698 725 754 785
000 000 000 000 000 000 000 000 000 000
104 108 111 115 119 122 126 130 134 139
000 000 000 000 000 000 000 000 000 000
143 148 152 157 162 166 171 177 182 187
0 2 4 6 8 10 12 14 16 18
1 1 1 1 1 1 1 1 2 2
050 150 260 380 510 650 810 970 150 350
0.97 1.04 1.11 1.19 1.27 1.35 1.44 1.54 1.64 1.74
110 112 114 116 118 120 122 124 126 128
60 64 67 71 76 80 84 89 94 100
500 100 900 800 000 400 900 700 700 000
19.1 20.0 20.9 21.8 22.7 23.7 24.7 25.8 26.9 28.0
220 222 224 226 228 230 232 234 236 238
1 1 1 1
816 848 881 915 950 987 020 060 100 140
20 22 24 26 28 30 32 34 36 38
2 2 3 3 3 3 4 4 4 5
560 780 030 290 570 880 210 560 940 350
1.85 1.97 2.09 2.22 2.36 2.50 2.65 2.81 2.98 3.16
130 132 134 136 138 140 142 144 146 148
106 111 117 124 130 137 144 152 160 168
000 000 000 000 000 000 000 000 000 000
29.1 30.3 31.6 32.9 34.2 35.6 37.0 38.5 40.0 41.6
240 242 244 246 248 250 252 254 256 258
1 1 1 1 1 1 1 1 1 1
190 230 270 320 370 420 470 520 570 630
000 000 000 000 000 000 000 000 000 000
192 198 204 210 216 222 229 235 242 248
40 42 44 46 48 50 52 54 56 58
5 6 6 7 7 8 9 9 10 11
780 240 740 280 850 460 110 800 500 300
3.34 3.54 3.74 3.96 4.18 4.42 4.66 4.92 5.19 5.48
150 152 154 156 158 160 162 164 166 168
177 186 195 205 215 225 236 248 259 272
000 000 000 000 000 000 000 000 000 000
43.2 44.9 46.6 48.4 50.2 52.1 54.1 56.1 58.2 60.3
260 280 300 320 340 360 380 400 420 440
1 2 3 4 5 7 9 11 14 18
680 340 180 260 610 270 300 700 700 100
000 000 000 000 000 000 000 000 000 000
255 333 430 548 692 869 1090 1360 1700 2130
60 62 64 66 68
12 13 14 15 16
200 100 000 000 100
5.77 6.08 6.41 6.74 7.10
170 172 174 176 178
285 298 312 326 341
000 000 000 000 000
62.5 64.8 67.1 69.5 72.0
460
22 200 000
NOTE 1—To correct A and B to other base conditions, multiply each by: ~Pb/14.7! 3 @519.6/~tb 1 459.6!# 3 ~0.998/Zb!
where: Pb = absolute base pressure, psia; tb = base temperature, °F; and Zb = compressibility factor under base conditions.
6
D 1142 – 95 (2000) TABLE 3 Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (lb/million ft3 where Pb = 14.7 psia, tb = 60°F) Temperature,
Total Pressure, psia
°F
14.7
100
200
300
400
500
600
700
800
900
1000
−40 −38 −36 −34 −32
9.1 10.2 11.5 12.8 14.4
1.5 1.7 1.9 2.1 2.4
0.88 0.98 1.1 1.2 1.3
0.66 0.73 0.80 0.90 0.99
0.55 0.61 0.68 0.74 0.82
0.49 0.54 0.59 0.65 0.72
0.44 0.49 0.54 0.59 0.65
0.41 0.45 0.50 0.55 0.60
0.39 0.43 0.47 0.51 0.57
0.37 0.41 0.45 0.49 0.54
0.36 0.39 0.43 0.47 0.51
−30 −28 −26 −24 −22
16.0 17.8 19.8 22.0 24.4
2.6 2.9 3.2 3.6 4.0
1.5 1.6 1.8 2.0 2.2
1.1 1.2 1.3 1.5 1.6
0.91 1.0 1.1 1.2 1.3
0.79 0.87 0.96 1.1 1.2
0.72 0.79 0.86 0.95 1.0
0.66 0.72 0.79 0.87 0.95
0.62 0.68 0.74 0.81 0.89
0.59 0.64 0.70 0.77 0.84
0.56 0.61 0.67 0.73 0.80
−20 −18 −16 −14 −12
27.0 30.0 33.1 36.7 40.5
4.4 4.9 5.4 5.9 6.5
2.4 2.7 3.0 3.3 3.6
1.8 2.0 2.2 2.4 2.6
1.5 1.6 1.8 1.9 2.1
1.3 1.4 1.5 1.7 1.8
1.1 1.2 1.4 1.5 1.6
1.0 1.1 1.2 1.4 1.5
0.97 1.1 1.2 1.3 1.4
0.92 1.0 1.1 1.2 1.3
0.87 0.95 1.0 1.1 1.2
−10 −8 −6 −4 −2
44.8 49.3 54.6 59.8 65.7
7.2 7.9 8.7 9.5 10.4
4.0 4.3 4.7 5.2 5.7
2.9 3.1 3.4 3.7 4.1
2.3 2.5 2.8 3.0 3.3
2.0 2.2 2.4 2.6 2.8
1.8 1.9 2.1 2.3 2.5
1.6 1.8 1.9 2.1 2.3
1.5 1.6 1.8 1.9 2.1
1.4 1.5 1.7 1.8 2.0
1.3 1.5 1.6 1.7 1.9
0 2 4 6 8
72.1 79.1 86.8 95.1 104
11.4 12.5 13.7 15.0 16.4
6.2 6.8 7.4 8.1 8.8
4.5 4.9 5.3 5.8 6.3
3.6 3.9 4.3 4.6 5.1
3.1 3.3 3.6 4.0 4.3
2.7 3.0 3.2 3.5 3.8
2.5 2.7 2.9 3.2 3.4
2.3 2.5 2.7 2.9 3.2
2.1 2.3 2.5 2.7 3.0
2.0 2.2 2.4 2.6 2.8
10 12 14 16 18
114 124 136 148 161
17.9 19.5 21.3 23.2 25.2
9.6 10.5 11.4 12.4 13.5
6.9 7.5 8.1 8.8 9.6
5.5 6.0 6.5 7.0 7.6
4.7 5.1 5.5 5.9 6.4
4.1 4.5 4.8 5.2 5.7
3.7 4.0 4.5 4.7 5.1
3.4 3.7 4.0 4.3 4.7
3.2 3.5 3.7 4.0 4.4
3.0 3.3 3.5 3.8 4.1
20 22 24 26 28
176 191 208 226 246
27.4 29.8 32.4 35.1 38.1
14.6 15.9 17.2 18.7 20.2
10.4 11.3 12.2 13.2 14.3
8.2 8.9 9.7 10.5 11.3
7.0 7.5 8.2 8.8 9.5
6.1 6.6 7.2 7.7 8.3
5.5 5.9 6.4 6.9 7.5
5.1 5.5 5.9 6.3 6.8
4.7 5.1 5.5 5.9 6.3
4.4 4.8 5.1 5.5 5.9
30 32 34 36 38
276 289 313 339 367
41.3 44.7 48.4 52.4 56.6
21.9 23.7 25.6 27.7 29.9
15.4 16.7 18.0 19.4 20.1
12.2 13.2 14.2 15.3 16.5
10.3 11.1 11.9 12.9 13.9
9.0 9.7 10.4 11.2 12.1
8.0 8.7 9.3 10.0 10.8
7.4 7.9 8.5 9.2 9.8
6.8 7.3 7.9 8.5 9.1
6.4 6.9 7.4 7.9 8.5
40 42 44 46 48 50 52 54 56 58
396 428 462 499 538 80 624 672 721 776
61.1 66.0 71.2 76.7 82.6 89.0 95.7 103 111 119
32.2 34.8 37.5 40.3 43.4 46.7 50.2 54.0 57.9 62.1
22.6 24.4 26.2 28.2 30.3 32.6 35.0 37.6 40.3 43.2
17.8 19.2 20.6 22.2 23.8 25.6 27.4 29.4 31.5 33.8
14.9 16.0 17.2 18.5 19.9 21.3 22.9 24.5 26.7 28.1
13.0 13.9 15.0 16.1 17.3 18.5 19.8 21.3 22.8 24.4
11.6 12.5 13.4 14.4 15.4 16.5 17.7 18.9 20.3 21.7
10.6 11.3 12.2 13.1 14.0 15.0 16.1 17.2 18.3 19.6
9.8 10.5 11.2 12.0 12.9 13.8 14.8 15.8 16.9 18.0
9.1 9.8 10.5 11.2 12.0 12.9 13.8 14.7 15.7 16.8
60 62 64 66 68
834 895 960 1030 1100
128 137 147 157 168
66.6 71.4 76.5 81.8 87.6
46.3 49.6 53.1 56.8 60.7
36.2 38.7 41.4 44.3 47.3
30.1 32.2 34.4 36.8 39.3
26.1 27.9 29.8 31.8 33.9
23.2 24.7 26.4 28.2 30.1
21.0 22.4 23.9 25.5 27.2
19.3 20.6 22.0 23.4 25.0
17.9 19.1 20.4 21.8 23.2
70 72 74 76 78 80
1180 1260 1350 1440 1540 1650
180 192 206 220 235 250
93.7 100 107 114 122 130
65.0 69.4 74.0 79.0 84.2 89.8
50.6 54.0 57.6 61.4 65.5 69.7
42.0 44.8 47.7 50.9 54.2 57.5
36.2 38.6 41.1 43.8 46.7 49.7
32.1 34.2 36.4 38.8 41.3 44.0
29.0 30.9 32.9 35.0 37.3 39.7
26.6 28.4 30.2 32.1 34.2 36.3
24.7 26.3 28.0 29.8 31.7 33.6
7
D 1142 – 95 (2000) TABLE 3 Continued Temperature,
Total Pressure, psia
°F
14.7
100
200
300
400
500
600
700
800
900
1000
82 84 86 88
1760 1870 2000 2130
267 285 303 323
138 148 157 167
95.6 102 108 115
74.2 79.0 84.1 89.4
61.4 65.3 69.5 73.8
52.8 56.2 59.7 63.5
46.7 49.7 52.8 56.1
42.1 44.8 47.6 50.5
38.6 41.0 43.5 46.2
36.7 37.9 40.3 42.7
90 92 94 96 98
2270 2410 2570 2730 2900
344 366 389 413 439
178 189 201 214 227
123 130 138 147 156
95.0 101 107 114 121
78.5 83.3 88.4 93.8 99.5
67.4 71.5 75.9 80.5 85.3
59.5 63.1 67.0 71.0 75.2
53.6 56.8 60.3 63.9 67.6
49.0 51.9 55.0 58.3 61.8
45.3 48.0 50.9 53.9 57.0
100 102 104 106 108
3080 3270 3470 3680 3900
466 495 525 557 589
241 256 271 287 304
166 176 186 197 209
128 136 144 152 161
105 112 118 125 133
90.4 95.8 101 107 114
79.7 84.4 89.3 94.5 99.9
71.6 75.9 80.2 84.9 89.7
65.4 69.2 73.1 77.4 81.7
... ... ... ... ...
110 112 114 116 118
4130 4380 4640 4910 5190
624 661 700 740 783
322 341 360 381 403
221 234 247 261 276
170 180 191 201 213
140 148 157 165 175
120 127 134 142 149
106 112 118 124 131
94.7 100 106 112 118
86.3 91.2 96.2 102 107
... ... ... ... ...
120 122 124 126 128
5490 5800 6130 6470 6830
828 874 923 974 1030
426 449 474 500 528
292 308 325 343 361
225 237 250 264 278
185 195 205 216 228
158 166 175 185 195
139 146 154 162 171
124 131 138 145 153
113 119 125 132 139
... ... ... ... ...
130 132 134 136 138
7240 7580 7990 8470 8880
1090 1140 1200 1270 1330
559 585 617 653 684
382 400 422 446 468
294 308 324 343 359
241 252 266 281 294
206 215 227 240 251
181 189 199 210 220
162 169 178 188 197
147 154 162 171 179
... ... ... ... ...
140 142 144 146 148
9360 9830 10 400 10 900 11 500
1410 1480 1560 1640 1720
721 757 799 840 882
492 517 545 573 602
378 397 419 440 462
310 325 343 360 378
264 277 292 307 322
231 243 256 269 282
207 217 229 240 252
188 197 207 218 229
... ... ... ... ...
8
D 1142 – 95 (2000) TABLE 4 Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (lb/million ft3 where Pb = 14.7 psia, tb = 60°F) Temperature, °F
Total Pressure, psia 100
200
300
400
500
600
700
800
900
150 152 154 156 158
12 12 13 14 14
14.7 100 700 300 000 700
1810 1910 2000 2100 2200
928 975 1020 1070 1130
633 665 697 732 767
486 510 534 561 588
397 417 437 458 480
338 355 372 390 409
296 311 325 341 357
264 277 290 305 319
240 252 263 276 289
160 162 164 166 168
15 400 ... ... ... ...
2300 2410 2540 2650 2780
1180 1230 1300 1350 1420
802 841 883 922 967
615 644 676 706 740
502 526 552 576 604
427 447 469 490 514
374 391 410 428 449
333 349 366 382 400
302 316 332 346 363
170 172 174 176 178
... ... ... ... ...
2910 3040 3190 3330 3480
1490 1550 1630 1700 1780
1010 1060 1110 1160 1210
775 810 847 885 925
633 661 691 722 754
538 562 587 613 640
470 491 513 535 559
419 437 457 477 498
379 396 414 432 451
180 182 184 186 188
... ... ... ... ...
3640 3800 3980 4150 4340
1860 1940 2030 2120 2210
1260 1320 1380 1440 1500
967 1010 1060 1100 1150
789 821 860 897 936
670 697 730 761 794
585 609 637 664 693
521 542 567 591 617
471 491 513 535 558
190 192 194 196 198
... ... ... ... ...
4520 4720 4920 5140 5350
2300 2410 2510 2620 2730
1570 1630 1700 1780 1850
1200 1250 1300 1360 1410
974 1020 1060 1110 1150
827 863 900 938 976
721 753 785 818 851
642 670 698 728 757
581 606 631 658 684
200 202 204 206 208
... ... ... ... ...
5570 5810 6050 6310 ...
2840 2960 3080 3210 3340
1930 2010 2090 2180 2270
1470 1530 1600 1660 1730
1200 1250 1300 1350 1400
1020 1060 1100 1150 1190
885 922 960 999 1040
788 821 854 889 924
712 741 771 803 835
210 212 214 216 218
... ... ... ... ...
... ... ... ... ...
3480 3620 3760 3910 4060
2360 2450 2550 2650 2760
1800 1870 1950 2020 2100
1460 1520 1580 1640 1710
1240 1290 1340 1390 1450
1080 1120 1160 1210 1260
961 999 1040 1080 1120
868 902 937 973 1010
220 222 224 226 228
... ... ... ... ...
... ... ... ... ...
4220 4390 4560 4730 4910
2860 2980 3090 3200 3330
2180 2270 2350 2440 2540
1780 1840 1910 1990 2060
1500 1560 1620 1680 1750
1310 1360 1410 1460 1520
1160 1200 1250 1300 1350
1050 1090 1130 1170 1220
230
...
...
5100
3460
2630
2140
1810
1580
1400
1260
240
...
...
...
4160
3170
2570
2180
1890
1680
1510
250
...
...
...
...
3770
3060
2590
2250
2000
1800
9
D 1142 – 95 (2000) TABLE 5 Equilibrium Water Vapor Contents of Natural Gases Above the Critical Temperatures (lb/million ft3 where Pb = 14.7 psia, tb = 60°F) Total Pressure, psia
Temperature, °F
1000
1500
2000
2500
3000
3500
4000
4500
5000
100 102 104 106 108
60.4 63.9 67.5 71.4 75.4
45.4 47.9 50.6 53.4 56.4
37.9 40.0 42.1 44.5 46.9
33.3 35.5 37.0 39.1 41.1
30.3 32.0 33.6 35.5 37.3
28.2 29.7 31.2 32.9 34.6
26.6 28.0 29.4 31.0 32.6
25.3 26.6 28.0 29.5 31.0
24.3 25.6 26.9 28.3 29.7
110 112 114 116 118
79.6 84.1 88.7 93.6 98.7
59.4 62.7 66.1 69.7 73.4
49.4 52.1 54.8 57.7 60.7
43.3 45.6 48.0 50.5 53.1
39.3 41.4 43.4 45.7 48.0
36.4 38.3 40.2 42.3 44.4
34.2 36.0 37.8 39.8 41.7
32.5 34.2 35.9 37.8 39.6
31.2 32.8 34.4 36.2 37.9
120 122 124 126 128
104 110 116 122 128
77.3 81.3 85.6 89.9 94.7
63.9 67.2 70.7 74.2 78.0
55.9 58.7 61.7 64.7 68.0
50.5 53.0 55.7 58.4 61.3
46.7 49.0 51.4 53.9 56.6
43.8 45.9 48.2 50.5 53.0
41.6 43.6 45.7 47.8 50.2
39.8 41.7 43.7 45.7 48.0
130 132 134 136 138
135 141 149 157 164
99.8 104 110 116 121
82.1 85.8 90.1 94.9 99.2
71.5 74.7 78.4 82.5 86.2
64.4 67.3 70.6 74.2 77.5
59.4 62.0 65.0 68.3 71.3
55.6 58.1 60.9 63.9 66.7
52.6 55.0 57.6 60.3 63.1
50.3 52.5 55.0 57.7 60.2
140 142 144 146 148
173 181 191 200 210
127 133 140 147 154
104 109 115 120 126
90.4 94.6 99.3 104 109
81.3 85.0 89.2 93.0 97.6
74.7 78.1 81.9 85.7 89.6
69.9 73.0 76.5 80.0 83.6
66.0 69.0 72.3 75.6 78.9
63.0 65.8 68.9 72.0 75.6
150 152 154 156 158
220 231 242 253 265
161 169 177 185 194
132 138 144 151 158
114 119 125 130 136
102 107 112 117 122
93.8 98.0 102 107 112
87.5 91.4 95.4 100 104
82.5 86.2 89.9 94.0 98.0
78.6 82.1 85.6 89.4 93.2
160 162 164 166 168
277 290 304 317 332
202 211 221 231 242
165 172 180 188 196
142 149 155 162 169
127 133 139 145 151
116 122 127 132 138
108 113 118 123 128
102 107 111 116 121
97.1 101 106 110 115
170 172 174 176 178
348 363 379 396 413
253 263 275 287 299
205 214 223 233 243
177 184 192 200 208
158 165 171 178 186
144 150 156 163 169
134 139 145 151 157
126 131 136 142 148
120 124 130 135 140
180 182 184 186 188
432 449 470 490 511
313 325 340 354 369
253 263 275 286 298
217 226 236 245 256
194 201 210 218 227
177 184 191 199 207
164 170 177 184 192
154 160 167 173 180
146 152 158 164 171
190 192 194 196 198 200 202 204 206 208
531 554 578 602 626 651 678 705 734 763
384 400 417 434 451 469 488 507 528 548
310 323 336 350 364 378 393 408 425 441
266 277 288 299 311 323 336 349 363 377
236 246 256 266 276 286 298 309 321 334
215 224 233 242 251 260 271 281 292 303
199 207 215 224 232 241 251 260 270 280
187 194 202 210 218 226 235 243 253 262
177 184 191 199 206 213 222 230 238 248
210 212 214 216 218
793 824 856 889 924
569 591 614 637 662
458 475 493 512 532
390 405 420 436 453
346 359 372 386 401
314 325 337 350 363
290 301 312 323 335
271 281 291 302 313
256 266 275 285 296
10
D 1142 – 95 (2000) TABLE 5 Continued Temperature, °F
Total Pressure, psia 3500
4000
220 222 224 226 228
959 996 1030 1070 1110
1000
687 713 739 767 795
1500
551 572 593 615 637
2000
469 487 504 523 542
2500
415 431 446 462 479
3000
376 390 404 418 433
347 360 372 386 400
324 336 348 360 373
4500
306 318 328 340 352
230
1150
824
660
561
495
448
413
385
363
240
1380
985
787
668
589
532
490
456
430
250
1640
1170
932
790
695
628
577
538
506
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