Additive Effects of Tyre Rubber Constituents upon Coal Liquefaction

Abstract

Coprocessing waste tyre and coal as one of the effective processing methods of both materials has been investigated. Upon coprocessing, the synergistic effects, such as the increase of conversion, the yields of oil and asphaltene constituents, were reported in comparison with the result of individual liquefaction of waste tyre or coal alone. However, interaction between tyre and coal to synergistic effects was not clarified. In this study, coprocessing coal with tyre rubber constituents [styrene-butadiene rubber (SBR) or natural rubber (NR)] was carried out to discuss the additive effects of tyre rubber constituents upon coal liquefaction. Upon coprocessing three kinds of coals with NR, the oil yield decreased and the residue yield increased. It was anticipated that polymerization between aliphatic radicals derived from NR and aromatic radicals from coal occurred. On the other hand, synergistic effects to upgrading, such as the increase of oil yield and the decrease of residue yield, were obtained upon coprocessing higher rank coal (Huaipei, C; 84%) with SBR. However, the synergistic effects were not observed on coprocessing lower rank coal (Wyoming, C; 67%) with SBR. Compared with liquefaction of SBR with the pressurized nitrogen gas, the amount of hydroaromatics increased on that with the pressurized hydrogen gas. Therefore, the synergistic effects were obtained on coprocessing Huaipei coal with SBR because hydrogen donation and hydrogen shuttling from the pressurized hydrogen gas were accelerated by addition of SBR. Accordingly, it was considered that the synergistic effects to upgrading on coprocessing coal with waste tyre were obtained owing to enhancement of hydrogen donation and hydrogen shuttling by the pressurized hydrogen gas and aromatics derived from SBR in tyre.