Ind. Eng. Chem. Process
276
region can be clearly seen. Due to the high viscosity of this sample and large pressure drop across the calorimeter, it was not possible to operate at lower inlet pressures. Thus, the two-phase vapor transition and data in the vapor region were not obtained. Acknowledgments
This work was supported by the Office of Fossil Energy, Department of Energy (Contract No. E (49-18)-2035). The authors wish to thank H. Omid and M. C. Hiza for experimental assistance and D. Thakkar and S. Holliman for assistance with the analyses. J. E. Dooley and C. H. Thompson of Bartlesville Energy Technology Center sumlied the Utah COED samde while P. M. Yavorskv of Pittsburgh Energy Technolo& Center supplied the Synthoil sample. Dr. c. V. Philip of Texas A & M University supplied the GC-MS results.
Des. Dev. 1904, 23, 276-278
Literature Cited "Technlcal Data Book-Petroleum Refining", 2nd ed., American Petroleum Institute, Division of Refinlng, Washington, DC, 1970; pp 5-19. Andrew, J. R. M.S. Dissertation, Colorado School of Mines, Goklen, CO, 1978. Dooley, J. E.;Sturm, G. P.; Woodward, P. W.; Vogh. J. N.; Thompson, C. H. "Analyzing Syncrude from Utah Coal"; Bartlesville Energy Research Center, Report of Investlgatlon No. BERC/RI-75/7, Bartlesvllie, OK, 1975. Holliman, S. L. M.S. Dissertation, Colorado School of Mlnes, Golden, CO, 1979. Kesier, M. G.; Lee, B. I . Hydrocarbon Process. 1976, 55(3), 153. McConnell, J. R.; Fleckenstein, R. R.; Kldnay, A. J.; Yesavage, V. F. Znd. fng . Cbem. Process Des. Dev. 1984, previous paper in this issue. Omid, H.; Andrew, J. K.; Yesavage, V. F.; Kidnay, A. J. Znd. Eng. Chem. Process Des. D e v . 1984, previous paper in this issue. Sharma, R. M.S. Dissertatlon, Colorado School of Mines, Golden, CO, 1977.
Received for review February 2, 1982 Accepted June 28, 1983
Supplementary Material Available: Tables of GC-MS results and enthalpy data for the coal liquids (10 pages). Ordering information is given on any current masthead page.
Enthalpy Measurements on DDstDllate Cuts of Syncrudes Produced from the Solvent Refined Coal Processes RaJ Sharma, James R. Andrew, Victor F. Yesavage,' and Arthur J. Kldnay Depatfment of Chemical and Petroleum Refining Engineering, Colorado School of Mines, Golden, Colorado 8040 1
Enthalpy data are presented at 14 pressures between 210 and 10340 kPa (30 and 1500 psia) for temperatures between 18.3 and 382 OC (65 to 720 OF) for a naphtha cut distilled from a coalderived liquid produced by the Solvent Refined CoaCI (SRCI) process. Data are also reported for two distillates produced by the Solvent Refined Coal-I1 (SRC-11) process. Measurements for the naphtha were obtained at pressures of 690, 1380, and 2060 kPa (100, 200, 300 psia) at temperatures from 18.3 to 237 OC (65 to 459 OF), and measurements for the middle boiling range distillate were obtained at pressures of 895, 1035, 2070,and 6895 kPa (130, 150, 300, 1000 psia) at temperatures from 18.3 to 357 OC (65 to 675 OF). The data were obtained in a Freon-11 (CFCI,) reference fluid boil-off calorimeter.
Introduction As a part of a continuing effort to obtain enthalpy measurements for coal-derived liquids and model compounds representative of coal-derived liquids, enthalpy measurements are presented for three distillate liquids produced from the two solvent refined coal processes, SRC-I and SRC-11. The data were obtained in a Freon 11 (CFClJ reference fluid boil-off calorimeter that has been described previously (McConnell et al., 1984). Based on previous evaluation studies, uncertainty in the measurements should be less than *LO% of the measured enthalpy values. Data have been previously reported for coal-derived liquids produced by the Char-Oil-Energy-Development (COED) (Omid et al., 1984; Andrew et al., 1984) and the Synthoil processes (Andrew et al., 1984). Experimental Section The boil-off calorimeter is described in detail elsewhere (McConnell et al., 1984). As in previous studies with coal liquids (Omid et al., 1984; Andrew et al., 1984), a major concern was the occurrence of sample decomposition at high temperatures. This was a particularly severe problem for the liquids of this investigation. To determine whether sample decomposition had an effect on the enthalpy measurements, low-temperature runs were repeated after high-temperature runs had been obtained. It was often 0196-4305/84/1123-0276$01.50/0
necessary to discard data in regions where it was believed that sample decomposition resulted in uncertainties greater than f1.0%. The details of the experimental difficulties are reported elsewhere (Andrew, 1978; Sharma, 1980). The three coal liquids were analyzed in detail and the results are listed in Tables I-IV. The measurements include physical properties, elemental analysis, and ASTM distillation. A gas chromatographic-mass spectrometer (GC-MS) analysis performed by Dr. C. V. Philip of Texas A&M University is presented as Supplemental Material in Table S l . For the GC-MS analyses 90% to 95% of the major peaks are identified, at least as far as compound type, for the two naphtha samples, but for the SRC-I1 middle distillate it appears that the separation techniques was not effective, for only 25% of the peaks could be identified. SRC-I Naphtha The sample, produced by the Pittsburg and Midway Coal Mining Company at the SRC-I pilot plant in DuPont, WA, was a light, amber-colored liquid and was charged to the calorimeter as received. Severe operational difficulties were often encountered at higher temperatures due to extreme compositional changes in the sample. At lower pressures and temperatures above 175 "C, a solid black product would often form 0 1984 American
Chemical Society
Ind. Eng. Chem. Process Des. Dev., Vol. 23, No. 2, 1984 277 Table 111. SRGII Naphtha (ASTM Distillation (D-86))'
Table I Physical Properties
molecular weight, wt av (no. av) bromine no., g/100 g, ASTM D1159 refractive index,
SRC-I naphtha
SRC-I1 middle distillate
132 (125)
120 (110) 2.3
%recovered (by vol)
SRC-I1 naphtha
IBP 5 10 15 20 30 40 50 60 70 80 90 95 end point recovery
115 (110)
35
1.438
1.5401
1.5392
0.781
0.976
0.820
0.28
3.57
0.87
nzO
specific gravity, (60" 160" kinematic viscosity, (100 O F ) , cSt, ASTM D 4 4 5 API K (Watson)
49.7 11.23
13.5 9.9
41.0 10.9
Elemental Analysesu element C
80.90
H
12.87
N
0.52
S
0.34
85.53 (85.85) 9.05 (9.07) '1.32' (1.10) 0.15
86.10 11.74
(by vel)
(138) (167) (180)
Temperature
' Distillation per-
179 199 204 21 2 214 220 225 229 236 24 2 252 260 27 8
(354) (390) (400) (413) (418) (428) (437) (445) (456) (468) (485) (500) (532) 98% 2 70
(I Distillation performed by Pittsburg and Midway Coal Mining Company, Solvent Refined Coal Pilot Plant, DuPont, WA.
20c
r SRC - I
Distillation performed by Pittsburg and Midway Coal Mining Company, Solvent Refined Coal Pilot Plant, DuPont, WA.
in the sample lines and preheater, totally blocking the flow. This material was insoluble in the common laboratory solvents (benzene, acetone, etc.) and was believed due to thermal cracking (coke formation) or to a polymerization reaction. When the reaction occurred, both the affected equipment and the sample were replaced. Enthalpy data were taken at 205,345,690,1035,1380, 1725,2070,2760,3445,4135,4825,6205,6895,and 10340 kPa (30,50,100,150,200,250,300,400,500,600,700,900, 1000,1500 psia) over a temperature range of 18.3 to 354 "C (65 to 670 O F ) and are presented in Table S2 as Supplementary Material and illustrated in Figure 1. The reference state for the enthalpy data is the liquid at 1 atm and 18.3 OC (65 O F ) . The data were adjusted to an outlet temperature of 18.3 "C (65.0 O F ) by using a heat capacity obtained from the slope of the data at low temperatures. This correction was in all cases less than f l . O kJ/kg. The value adjusted to 18.3 O C is the number reported as the experimental enthalpy in Table S2. The adjustment from
(150) (172) (193) (216) (224) (242) (256) (275) (293) (312) (335) (362) (406) (413) 97.5%
temp, "C ( O F )
IBP 5 10 20 30 40 50 60 70 80 90 95 end point recovery residue lost
temp, "C ("F)
(194) (205) (216) (229) (246) (266) (287) (325) (350) (373) 98%
66 78 89 102 107 117 124 135 145 156 168 183 208 212
% recovered
1.18
% recovered
59 75 82 90 96 102 109 119 130 142 163 177 189
(139) (160) (187) (204) (213) (230) (246) (263) (282) (298) (323) (350) (391) (398) 97.5%
Table IV. SRC-I1 Middle Distillate (ASTM Distillation (D-86), 1 atm)'
Table 11. SRC-I Naphtha (ASTM Distillation (D-86), 1 atm)"
IBP 5 10 20 30 40 50 60 70 80 90 95 end point recovery
59 71 86 96 101 110 119 128 139 148 162 177 199 203
corr temp, "C
Ambient pressure at Golden, CO. corrected to 1 atm using API (1970). formed by Colorado School of Mines.
Data in parentheses measured at Texas A & M University.
(by vel)
temp, "C ( O F ) at 0.81 a t m u
h4PLITHA
205 kPo 345 kPo 690 k P o '035 kPa I380 XPO
*
1725 kPo 207C kPa 2760 k P 0
+
3445 kPD
w
0 4825
kPa
6205
kPI
0
50
1 I00
1
,
I
I
150
20C
250
300
J
350
400
TEMPERATURE, "C
Figure 1. Enthalpy as a function of temperature for an SRC-I naphtha at numerous pressures.
system outlet pressure to 1 atm was made with the Kesler-Lee (1976) correlation and this correction, shown in the correction and corrected enthalpy columns of Table 6, was always less than 1.5% of the enthalpy value. Thus, even a significant percentage error in the correlation would
Ind. Eng. Chem. Process Des. Dev., Vol. 23, No. 2, 1984
278
630 -
S R C II NAPHTHA m
2#
5
400 -
a >.
F z
/-
200
0 63OkPo n 1380kPo 2060 kPo
SRC= MIDDLE DISTILLATE
_:I
/
x -3 0 600
01
'
0
" xi
I 00
TEMPERATURE,
1
I
1
I50
200
250
OC
400 W z
Figure 2. Enthalpy as a function of temperature for an SRC-I1 naphtha at 690, 1380, and 2060 kPa.
have only a small effect on the overall accuracy of the data reported here. The sample critical point was low enough so that data around the entire phase envelope were obtained, as illustrated in Figure 1. As seen from the figure, there is a negligible effect of pressure on the liquid enthalpy, since liquid data for all pressures fall on essentially the same curve. As the temperature is increased, the isobars clearly break from the liquid line. The break point is the bubble point of the naphtha at the given pressure. The sharply rising portions of the curves are in the two-phase region. At higher pressures the breaks become less distinct until at some pressure greater than 4000 kPa the critical pressure is reached. The data also clearly show the effect of pressure on the enthalpy differences for the vapor. As the pressure decreases at constant temperature, the enthalpy increases. Because of this effect of pressure on the vapor enthalpy differences, the dew point temperatures are much less identifiable. SRC-I1 Naphtha The naphtha sample used in this investigation was produced by the Pittsburg and Midway Coal Mining Company at their DuPont, WA, pilot plant by use of the SRC-I1 process. The sample was used as received. Liquid-phase enthalpy measurements in the temperature range of 18.3-237 "C (65 to 459 OF), along 690,1380, and 2060 kPa (100,200,300 psia) isobars are presented in Table S3 submitted as Supplementary Material and illustrated in Figure 2. The outlet temperature was also corrected to the base of 18.3 "C by using the heat capacity at this temperature as found from the measured enthalpy vs. temperature curve. Again this correction never amounted to more than 1.0 kJ/kg. The outlet pressure correction to a reference of 1 atm using the Kesler-Lee correlation was always less than 1.5% of the enthalpy value, as shown in Table S3. From Figure 2 it can be seen that the liquid-phase enthalpy is not a significant function of the pressure. No enthalpy data in the two-phase or the vapor regions could be obtained due to severe operational problems caused by the thermal instability of the sample. Severe "coking" or polymerization due to compositional changes occurred in the sample lines and the preheater, resulting in frequent shutdowns and replacement of the affected equipment. Repeated attempts at obtaining enthalpy data in the two-phase and the vapor regions by charging fresh samples to the system were unsuccessful. SRC-11 Middle Distillate The middle distillate sample used in this study was also furnished by the Pittsburg and Midway Coal Mining Company and was produced from a Kentucky coal at their DuPont, WA, pilot plant using the SRC-I1 process. En-
0
' 50
I
I
I
I
I
I
I
I00
150
200
250
300
350
4OC
TEMPERATURE,
O C
Figure 3. Enthalpy as a function of temperature for an SRC-I1 Middle distillate at several pressures.
thalpy measurements in the temperature range of 18.3-357 "C (65-675 O F ) along 895,1035,2070, and 6895 kPa (130, 150, 300,1000 psia) isobars were obtained on the middle distillate cut and are presented in Table S4 submitted as Supplementary Material and illustrated in Figure 3. The outlet temperature and pressure were corrected to 18.3 OC and 1.0 atm, respectively, using the same procedure as outlined for the SRC-I1 naphtha sample. Severe operational problems were caused by the thermal instability of the sample. At moderate pressures (on the order of 1035 P a ) , and at temperatures greater than 260 "C, severe plugging problems quickly developed in the system. As shown in Figure 3, some two-phase data were obtained for this sample at pressures of 896 and 1034 kPa. However, repeated attempts at obtaining enthalpy data in the two-phase and the vapor regions, at the higher isobars, by charging fresh samples to the system were unsuccessful. Acknowledgment This work was supported by the Office of Fossil Energy, Department of Energy (Contract No. E(49-18)-2035). The authors wish to thank H. Omid and M. C. Hiza for experimental assistance and D. Thakkar and S. Holliian for assistance with the analyses. J. P. Naylor of the Pittsburg and Midway Coal Mining Company provided the SRC-I naphtha. The SRC-I1 samples were also provided by the Pittsburg and Midway Coal Mining Company. Dr. C. V. Philip of Texas A&M University supplied the G C M S results. Literature Cited "Technlcal Data Book-Petroleum Refinlng", 2nd ed., American Petroleum Instltute, Dlvlsion of Refining; Washington, DC, 1970; pp 5-19. Andrew, J. R. M.S. Dissertation, Colorado School of Mlnes, Golden, CO, 1978. Andrew, J. R.; Sharma, R.; Kldnay, A. J.; Yesavage, V. F. Ind. Eng. Che" Process Des. Dev. 1984, previous paper In thls Issue. Holliman, S . L. M.S. Dissertation, Colorado School of Mines, W e n , CO. 1979. Kesler, M. Q.; Lee, B. I. Hydrocarbon Process 1976, 55(3) 153. McConnell, J. R.; Fleckenstein. R. R.; KMnay, A. J.; Yesavage, V. F. Ind. Eng Chem Process Des. Dev. 1964, prevbus paper in this issue. Omld. H.; Andrew, J. R.; Yesavage, V. F.; KMnay, A. J. Ind. f n g . ch8m. Process Des. Dev. 1984, previous paper in thls Issue. Sharma, R. FkD. Dissertation, Colorado School of Mlnes, Golden, CO, 1980.
.
.
Received for review February 2, 1982 Accepted June 28, 1983
Supplementary Material Available: Tables of GC-MS results and enthalpy data for the coal liquids (14 pages). Ordering information is given on any current masthead page.
