Solvent effects of fractions from coal liquid on the upgrading reaction of coal liquefaction residue

Solvent effects of fractions from coal liquid on the upgrading reaction of coal liquefaction residue

Coal Science J.A. Pajares and J.M.D. Tasc6n (Editors) 9 1995 Elsevier Science B.V. All rights reserved. 1475 S o l v e n t effects of f r a c t i o ...

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Coal Science J.A. Pajares and J.M.D. Tasc6n (Editors) 9 1995 Elsevier Science B.V. All rights reserved.

1475

S o l v e n t effects of f r a c t i o n s f r o m coal l i q u i d on t h e u p g r a d i n g r e a c t i o n of coal l i q u e f a c t i o n r e s i d u e Kiyoshi Mashimo, Motoyuki Sugano and Tohru Wainai Department of Industrial Chemistry, College of Science and Technology, Nihon University 1-8, Kanda Surugadai, Chiyoda-ku, Tokyo 101, Japan Coal liquefaction residue (CLR) produced abundantly in the process of hydrogenolysis reaction of coal are constituted of the heavy materials of aromatic compounds with poor reactivities. Minerals in coal are also concentrated in CLR. However, it has been manifested that dichloromethane soluble in CLR acts as a good hydrogen-donor 1). Thus, the studies that utilize CLR as the useful carbon resources have been widely practiced. On the other hand, the primary hydrogenolysis products yielded simultaneously with CLR contain significant amounts of basic fraction 2), the secondary hydrogenolysis reactions for purposes of the effective denitrogenation of basic fraction are necessitated. In this study, the co-upgrading reactions of mixture of CLR and coal liquid fraction were carried out, the synergistic effects for hydrogenolysis were investigated. 1. EXPERIMENTAL 1.1. Primary hydrogenolysis reaction of coal Muswellbrook coal (30g) was hydrogenated with 40g of tetralin in a 200 cm 3 autoclave at 400~ for 1 h under an initial pressure of 3.9 MPa. The hydrogenolysis products were separated into dichloromethane insoluble (coal liquefaction residue : CLR) and dichloromethane soluble (primary liquid oil : DS). Further, DS was separated into basic (B), neutral (N) and acidic (A) fractions by ion-exchange chromatography. 1.2. Secondary hydrogenolysis reactions An amount (3.6g) of mixture of any one of A, N and B and CLR was further hydrogenated by adding 0.36g of red-mud and 0.036g of sulfur promotor as catalyst and 7.0g of decalin at 420~ for 1 h under an initial hydrogen

1476 pressure of 5.9 MPa in a 200 cm 3 autoclave, dichloromethane insoluble (DI) and dichloromethane soluble (secondary liquid oil) were obtained. Similarly, each hydrogenolysis reaction of B, N, A and CLR alone was also carried out. The secondary liquid oil was further extracted with hexane in a Soxhlet extractor. Hexane soluble (HS), and hexane insoluble and dichloromethane soluble (HIDS) materials were prepared. 2. RESULTS AND DISCUSSION 2.1 Properties of the primary hydrogenolysis products The conversion of the coal was 50%. Because the proportion of yields of CLR and DS showed a ratio of 55 to 45, the proportion of CLR to each fraction in the secondary hydrogenolysis reactions was prepared at the same ratio. DS consists of 48% of basic, 39% of neutral and 13% of acidic fractions. B consists of nitrogen heterocyclic aromatic compounds having pyridine skeleton. N is mainly constituted of long straight-chain alkanes and aromatic compounds with long chain alkyl groups. A consists of polycyclic aromatic compounds containing oxygen functional groups such as phenolic hydroxyl group and carboxyl group. 2.2. Secondary hydrogenolysis reactions The yields of constituents derived from the secondary hydrogenolysis reactions of single samples are shown in Figure 1. The yields in the secondary hydrogenolysis of mixture of CLR and any one of B, N and A are shown in Figure 2. Further, by using the results in Figures 1 and 2, and the equations (1) and (2), the increase and decrease in the yields of constituents was calculated from the yields in the reactions of each sample alone in addition to the yields in the reactions of mixture of CLR and any one of B, N and A. The variation in the yield of each constituent is shown in Figure 3. W WCLR) Yield (%)= Fmix- ( F XWm,, + F c L R X Wm ix ix

(1)

Wmix=W+WcLR

(2)

where W and W CL R are amounts (g) of liquid oil fraction and CLR, respectively. Fmi x is yield (%) of each constituent from the secondary reaction of mixture, F and FCL R are yields (%) of constituents from the secondary reactions of liquid oil fraction alone and CLR alone, respectively.

1477

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Figure 3. Variation in yields by the hydrogenolyses of mixture of CLR and any one of N, A and B

1478 2.2.1. Reaction of CLR with neutral oil fraction (N) or acidic oil fraction (A) In the reaction of mixture of CLR and N, the decreases of HS and HIDS and the increase of DI were observed. The catalyst deactivation occurred by the adsorption on the catalyst surface of highly condensed aromatic compounds in CLR. Therefore, the hydrogenolysis of aromatic compounds in N and the conversion of CLR to dichloromethane soluble were inhibited. In the reaction of mixture of CLR and A, since there were little interaction between CLR and phenols in A, the conversions of A to HS and CLR to dichloromethane soluble were inhibited by the catalyst deactivation described above. 2.2.2. Influence of composition changes in the reaction of CLR with basic oil fraction (B) The reactions of various proportions of CLR and B were carried out. The degree in the increase and decrease of each constituent produced was calculated by the equations (1) and (2). The results are also shown in Figure 3. As shown in this figure, in the reaction of 10% of CLR, the yields of gas and HS increased, and those of HIDS and DI decreased. As the proportions of CLR were taken at higher concentration, the yields of gas and HIDS decreased and increased, respectively. Especially, in the reaction of 55% of CLR, the synergistic effects such as the increase of HS and the decrease of DI were observed. However, the effects were not found in the reaction of 75% of CLR. Therefore, in the reactions of the concentrations of CLR from 10% to 55%, B that penetrated into the structures of CLR promotes the dissolution and dispersion of CLR. The poisoning for catalyst is not easy to occur compared to the reaction of B or CLR alone, the synergistic effects appear. REFERENCES 1. S. Futamura and K. Ohkawa, 1993 Proc. Int. Conf. on Coal Sci., ]I p.509 2. M. Sugano, K. Mashimo and T. W ainai, J. Japan Inst. Energy, 73, 203 (1994)