34
Ind. Eng. Chem. Prod. Res. Dev. 1900, 19, 34-38
Lang, E. W., Smith, H. G . , Bordenca, C., Ind. Eng. Chem.,49,355-59 (1957). Margaritis, P. J., Kim, S. S., Cherish, P., Salvador, L. A,, "Operation of the Westinghouse Fluidized 5 s d bvolatiliier with a Variety of Coal Feedstocks", presented at the Symposium on Gasification of Coal to Produce Low-BTU Gas, American Chemical Society, New Orleans, La., Mar 21-25, 1977. Merrill, R . C., Scotti, L. J.. Ford. L., Domina, D. J., Chern. Eng. Prog. Coal
Division of Petroleum Chemistry, Mar 20-25, 1977. Struck, R. T., Dudt, P. J., Gorin, E., Ind. Eng. Chem. Process Des. Dev., 6,
85-88 (1967). The Ralph M. Parsons Company, "Coal Liquefaction Process Research Process SUNey", R & D Interim Report NO. 2, ORNL/S~b-7186/13, 1977.
Process. Techno/.,2, 88-93 (1975). Oberg, C. L., "Partial Liquefaction of Coal by Direct Hydrogenation", FE2044-22,Quarterly Progress Report, April-June 1977. Stambaugh, E. P., Miller, J. F., Tam, S. S.,Chauhan, S. P., Feldmann, H. F., CarRon, H. E., Nack, H., Oxley, J. H., Environmentally Acceptable Solid Fuels by the Battelle Hydrothermal Coal Process". presented at the Second Symposium on Coal Utilization, Louisville, Ky., Oct 21-23, 1975. Stambaugh, E. P., Feldmann, H. F., Lin, K. T., Sckhar, K. C., Chauhan, S. P., Oxley, J. H., "Novel Concept for Improved Pyrolysis Feedstock Production", presented at the New Orleans Meeting of the American Chemical Society,
Received for review May 7, 1979 Accepted December 10, 1979 Presented at the American Institute of Chemical Engineers 86th National Meeting, Houston, Texas, Apr 1-5, 1979. The research was sponsored by the Fossil Energy Office, U S . Department of Energy, under Contract W-7405-end-26 with Union Carbide Corportion.
Alternative Modes of Processing SRC in an Expanded Bed LC-Finer to Produce Low Nitrogen Distillates Richard S. Chiillngworth, Kenneth E. Hastlngs, and John D. Potts' Cities Service Company, Technology Assessment Department, Tulsa, Oklahoma 74 102
Harold Unger C-E Lummus Company, A Subsidiary of Combustion Engineering, Inc., Engineering Development Center Annex, New Brunswick, New Jersey 08902
The feasibility of utilizing an expanded bed reactor (LC-Fining process) for upgrading SRC-I has been previously demonstrated with respect to conversion of 850 OF+ and desulfurization in both a once-through and recycle mode of operation. Further investigative PDU runs were made to provide a better understandingof the process. These include: delineation of the separate effects of solvent and SRC, processing an SRC from Western coal, feed blend ratios of 70/30 rather than 50/50 volume percent SRC/solvent, and a solvent IBP of 680 OF rather than 500 OF. A nitrogen level of C0.3 wt % in the distillate products (390-850 O F ) was readily achieved with an accompanying sulfur level of 32 to 128 ppm. Catalyst activity was maintained with only small temperature adjustments. Preliminary resutts indicate that a higher boiling range solvent (680 vs. 500 OF) provided enhanced denitrogenation. Proprietary LCFining expanded bed correlations for residuum processing of petroleum are applicable to coal liquids processing. This paper clearly shows the versatility and adaptability of a commercial petroleum refining process (LC-Fining) for upgrading SRC.
Introduction Several years ago discussions were initiated between Cities Service Company and the Energy Research and Development Administration (ERDA), now a part of the Department of Energy, which resulted in a government sponsored development contract. The original contract with ERDA involved process development unit (PDU) operation to determine the feasibility of operating an LC-Finer (Service Mark of the Lummus Co. and Cities Service Co.) to process solvent refined coal (SRC-I) and also to determine the optimum operating conditions for conversion and desulfurization. C-E Lummus, with laboratory process development units for LC-Fining located in New Brunswick, N.J., was chosen as the subcontractor for this project with Cities being the prime contractor. The choice of subcontractor was especially judicious as C-E Lummus is the exclusive worldwide licensor of the proprietary LC-Fining process and has an excellent perspective of the operating parameters. The success of the original contract in determining the feasibility of utilizing an LC-Finer for upgrading SRC-I stimulated further interest in this method of operation by DOE. A greater emphasis was placed on nitrogen removal 0 196-43211801 121 9-0034$01 .OO/O
since good conversion and desulfurization had been adequately demonstrated. Consequently, a contract extension was granted. Special effort was placed on the use of commercially available catalysts. It should be emphasized that the success achieved in this contract was obtained by use of a commercial petroleum refining process (LC-Fining) and commercial off-the-shelf catalysts. The PDU studies were performed for the purpose of determining proper operational conditions for a future commercial design application. The specific objectives of this paper will be to describe the results obtained from: (a) processing with a 70/30 vol 70 SRC/solvent ratio rather than the previously utilized 50/50 vol 70;(b) processing with a higher boiling range solvent, namely 680 O F IBP rather than 500 O F IBP; (c) processing SRC derived from a Western coal; (d) processing with cool noncatalytic zones ( Z 6 5 0 O F ) . Experimental Section The operation of an LC-Finer is best described by means of a process flow schematic (Figure 1). The LC-Finer reactor maintains the catalyst (typically American Cyanamid 1442B cobalt molybdenum 1/32 in. extrudate or Shell
0 1980 American Chemical Society
LC-FINING PROCESS
Figure 1. LC-Fining Process.
-
324 nickel molybdenum 1/32 in. extrudate) in constant motion, suspended by the recirculation of copious volumes of liquid. This recirculation results in a 35-507'0 bed expansion and the reactor operates at a uniform temperature with essentially no pressure drop. In a commercial unit there is a recycle of gas and liquid to be combined with the fresh SRC or residuum feed. The PDU differs from the commercial unit design in that there is no recycle gas or liquid streams. The bed expansion is maintained with an external recirculation loop. It should be noted that the PDU fractionator separates the liquid product into a light oil (L.O.) and a heavy oil (H.O.). The combination of these two oil streams is designated as total liquid product (TLP). Results and Discussion Conclusions Derived from Prior Studies. Two technical papers have previously been presented which describe in detail the results of the initial studies involved in expanded bed hydroprocessing of SRC-I (Hastings et al., 1978; Chillingwotth et al., 1978). Two DOE Interim Technical Progress Reports have also been published and are available for distribution (Potts et al., 1977, 1978). This previously reported Rork may categorically be subdivided into the following are,m: (a) preliminary 10-day operating periods to investigate the effect of solvent type and feasibility of operation; (b) first 30-day aging study (Co/Mo); (c) catalyst screening; (d) 30-day operation-once-through and recycle mode (Ni/Mo). From these data it may be concluded that: (a) expanded bed LC-Finer processing for upgrading SRC-I is feasible a t a conversion of 854- wt % 850 O F + and a denitrogenation of 70+% in the 850 O F + fraction (60+% in the TLP); (b) trends have been established which provide information for optimizaton; (c) proprietary LC-Fining correlations for residuum processing of petroleum are applicable to coal liquids processing; (d stable operation has been achieved in once-through operation for up to 33 days and in recycle operation for up to 41 days; (e) a distillate product (39G350 O F ) was malde containing 0.3 wt % nitrogen; (f) catalyst aging rate for conversion and denitrogenation is not damaged by recycling unconverted 850 OF+; (g) techniques are available to restore and retain catalytic activity by catalyst addition while on stream and/or by the use of an expanded bed demetallization reactor. PDU Operation-Current Study. The current paper will present the results of four alternate processing modes utilizing an expanded catalyst bed for hydroprocessing SRC: (1)feed blend consisting of 70.8 wt % SRC-I/29.2 wt 70 prehydrogenated 500 OF IBP Koppers Heavy Residue Creosote Oil (normally 50/50 SRC-I/KC-Oil); (2) feed blend consisting of nominally 50 wt % SRC-I/50 wt 70 prehydrogenated 680 O F IBP KC-Oil; (3) feed blend con-
Ind. Eng. Chem. Prod. Res. Dev., Vol. 19, No. 1, 1980 35 Table I.
Feedstock Component Analysis SRC-1 nominal solvent 500 " F refined solventa coal
gravity, API pour point, " F softening point, "F elemental analysis, wt % carbon hydrogen oxygen sulfur nitrogen distillation, " F IBP 5% 3 0% 5 0% 95% a
-3.6 -5 --
-16.5
-19.0 -_ 33 2
__
353
92.2 6.7 0.6 0.1 0.4 337 460 570 600 850
Amax solvent refined coal
86.2 5.7 4.4 0.8 2.1 620 850
__
88.7 5.7 4.6 0.2 1.4 92.9 vol % 8 5 0 OF+
__
Prehydrogenated Koppers heavy residue creosate oil.
Table 11. Feed Blend Properties
__ -
identity wt % SRC wt % solvent sulfur, wt % nitrogen, wt % ash, wt % IBP-650 " F vol % sulfur, wt % nitrogen, wt % 650-850 " F vol % sulfur, wt % nitrogen, wt % 8 5 0 OF+ vol % sulfur, wt % nitrogen, w t % a
6
run no. (2LCF-) 7-7/15
680°F 49.3 50.7 0.43 1.80 1.24 0.10 0.11
70/30 70.8 29.2 0.51
11
8
6 8 0 ° F Amax 53.3 48.2 51.8 46.7 0.14 0.40 0.85 1.15 0.17 0.09
10 cool 55.5 44.5 0.45 1.25 0.10
12.0 0.09
