INDUSTRIAL AND ENGINEERING CHEMISTRY
802
the 0.1% level to react stoichiometrically with all the hydrogenative metal present. The difference in performance a t the two levels could, therefore, not be expected to disappear if the runs were extended to multiples of the 4 hours used in these experiments. Commercial operation a t 300 pounds per square inch gage is usually carried out with relatively narrow boiling fractions which will not normally contain as much as 0.5yosulfur in the feed: commercial units, however, utilize a hydrogen recycle system and sulfur may build up in the hydrogen recycle stream. At a 10 to 1 molar recycle ratio of gas to oil, for instance, 0.1% sulfur in the feed would roughly correspond to 0.5% sulfur in feed for a once-through operation with fresh hydrogen. In the present series of experiments the pure naphthenic feed stocks used tested the catalyst more severely than would a feed stock containing only 40 to 50% naphthenes. The poisoning effect is, therefore, expected t o be less pronounced with commercial hydrocarbon mixtures.
T.ABLE1x1.
DEHYDROISOR.iERIZATIOIV O F SULFUR CONTAINING blETHYLCYCLOPENTANE O V E R HOUDRIFoRMIh-GCATALYSTS
0.5% S, 950’ F., 300 lb./sq. inch gage, LHSV = 6 vol./vol./hour, Hz/oil = 4 moles) Aromatics in Product. Val.% No S 6 Loss of ConSulfur Compound in feed in feed version, % Hydrogen sulfide 40 26 35 31 25 19 Sulfura n-Butyl mercaptan 42 23 45 Diethyl sulfide 37 22 41 Ethylsdisulfide 36 23 36 Phenyl mercaptan 36 21 42 Thiophene 37 28 24 u
70S
.= 0.37.
added sulfur compounds were almost completely converted to hydrogen sulfide. At sulfur concentrations around 0.5%, the dehydrogenation function of the catalyst suffers some deactivation. However, when the sulfur concentration is reduced to 0.1 and 0.2’%, no effect on the dehydrogenation function is observed. B catalyst which had been employed for 2000 hours in the Houdriforming of a low-sulfur naphtha showed some deactivation during 4 hours’ exposure to 0.5% sulfur, but recovered this loss in activity when the sulfur was removed from the feed. Fresh catalyst under the same conditions suffered some permanent deactivation.
TABLE V.
EFFECT OF SULFURCOKCENTRATION AND OPERATING PRESSURE O N CONVERSION
TABLE IV.
(950’ F., LHSV = 6 vol./vol./hour, Hn/oil = 4 moles) Arom. in Product, HydroOperating vel.% Pressure, No S S carbon S in In Feed, Lb./Sq. in in Sulfur Compound Feed % Inch Gage feed feed Diethyl sulfide MCP 0.5 300 37 22 0.2 300 33 35 0.1 300 36 37 Phenyl mercaptan
MCP MCH
0.5 0.1 0.5 0.5 0.5
300 300 500 300 600
36 39 31 93 82
21 40 28 75 77
LOSS of Conversion,
%
41 0 0
REVERSIBILITY O F EFFECT OF SULFURCOMPOENDS ox CONVERSIOS
(0.5% S in X C P , 950’ F., 300 lb./sq. inch gage, LHSV = 6 vol./vol./hour, Hn/oil = 4 moles) Loss of Cmversion, 70 Aromatics in Product, Val.%- ~~~i~~ After Sulfur Before S During S -4fter S 4-hour 10-hour Compound Catalyst addition addition addition poisoning recovery S Fresh 31 25 31 19 0 HzS Fresh 40 26 40 35 0 n-BUSH Fresh 42 23 30 45 28 EtzS Fresh 37 22 30 41 17 EtzSz Fresh 36 23 33 36 9 PhSH Fresh 36 21 28 42 23 Thiophene Fresh 37 28 37 24 0
PhSH
Used
21
14
21
33
0
LITERATURE CITED (1) Am. Soc. Testing Materials, ASTM Designation, D 90-SOT. (2) Am. Soc. Testing Materials, ASThI Designation, D 875-46T, “Chemical PONA,” Es-45A. (3) Griddle, D. TT., and LeTourneau, R. L., Anal. Chern., 23, 1620 11951). (4) Faragher, W. F., Morrell, J. C., and Monroe, G. S., IND.ENG. CHEM., 19, 1281 (1927). ( 5 ) Heinemann, H., Mills, G. A., Hattman, J. B., and Kirsch, F. W,, Ibid., 45, 130 (1953). I
In case of catalyst deactivation due to the effect of sulfur compounds in the feed, it is important to know whether the catalyst will recover during normal operation if the sulfur irritant is removed from the feed, Data in Table V show that when fresh Houdriforming catalyst i8 used, the poisoning effect is not completely reversible for all sulfur deactivants. However, complete reversibility prevails if an equilibrium catalyst is used rather than fresh catalyst. Although this needs further confirmation, it seems probable that the permanent poisoning effect observed with fresh catalyst is of the character of an accelerated aging and t h a t once the catalyst has reached the slightly deactivated level a t which it will normally operate for thousands of hours with very little change, sulfur deactivation is reversible. The used catalyst employed in the example of Table V had more than 2000 hours of previous operation on a low sulfur naphtha.
Vol. 45, No. 4
,
(6) Heinemann, H.. Schall, J. W.. and Stevenson. D. H.. Petroleum Refiner,30, 107 (1951). ( 7 ) Kirkbride, C. G., I b i d . , 30, 95 (1951). (8) Mills, G. A., Heinemann, H., Milliken, T. H., and Oblad, A. G., IND.ENG.CHEM.,45, 134 (1953). RECEIVED for review August 27, 1952. ACCEPTED December 20, 1952. Presented before the Meeting-in-Miniature, Philadelphia Section, AMERICAN SOCIETY, January 29, 1953. CHEMICAL
Vapor-Liquid Equilibria a t 760 Mm. Pressure-Correction I n the paper, “Vapor-Liquid Equilibria a t 760 Mm. Pressure: 2-Propanol-Methanol, 2-Propanol-Ethyl Alcohol, 2-PropanolPropanol, and 2-Propanol-2-Butyl Alcohol Systems [Louis H. Ballard, and M. Van Winkle, IND.ENG. CHEM., 44, 2450 (1952)], the title should be replaced by: “Vapor-Liquid Equilibria at 760 Mm. Pressure: 2-Propanol-Methanol, 2-Propanol-Ethyl Alcohol, 2-Propanol-Propanol , and 2-Propanol-Isobutyl Alcohol Systems.” The Editors regret this error.
42 0
10 19 6
CONCLUSIONS
Houdriforming catalysts are excellent desulfurization agents. Under the conditions of the present series of experiments, all the
Materials of Construction Review of Ceramics-Correction In his Review of Ceramics for 1952 [IND.EKG.CHEM.,44, 2298 (1952)], the author wishes to delete “corundum and Carborunduni” from his list of causes of silicosis. Dust from these materials, when in use, does not cause silicosis. FELIXSINGER
