Objective Tar-rich coals are valuable resources integrating coal, tar, and gas properties. Catalytic pyrolysis serves as a significant approach for achieving green and low-carbon development of tar-rich coals. However, the research and development of efficient and recyclable catalysts for the pyrolysis of tar-rich coals remains highly challenging.
Methods With HZSM-5@SiO2@MgFe2O4 (HSMF) as the raw material, this study prepared HZSM-5@SiO2@MgFe2O4 (mHSMF) with a hierarchical porous structure using the hydrothermal method and alkali modification, followed by the preparation of cerium-modified mHSMF (5-CeO2/mHSMF) using the precipitation method. Employing a fixed-bed reactor, this study investigated the regulatory effects of 5-CeO2/mHSMF on the pyrolysis products of tar-rich coals from the Shenfu block, along with the anti-carbon deposition performance of 5-CeO2/mHSMF.
Results and Conclusions The results indicate that the CeO2-based modification of HSMF was conducive to the formation of a hierarchical porous structure comprising micropores and mesopores on the surface of HSMF. Through pyrolysis at 650°C in the N2 atmosphere for 1 hr using 5-CeO2/mHSMF as a catalyst, the coals exhibited a tar yield of 13.38%, equivalent to a tar yield of 176% in the Gray-King assay. Compared to the pyrolysis of raw coals, the catalytic pyrolysis exhibited increases in the aliphatic-hydrocarbon and benzene-compound contents in tar of 3.04% and 3.07%, respectively and an increase in the H2 and CH4 content in coal gas of 10.49%. Through CeO2-based modification, the catalyst enhanced the anti-carbon deposition performance by 86.1%, with carbon deposits of merely 11.60 mg/g and tending to form a stable graphitized structure. Overall, 5-CeO2/mHSMF manifests significant regulation of the distribution and composition of the products from the catalytic pyrolysis of coals in the Shenfu block, along with encouraging anti-carbon deposition performance and magnetic recyclability.
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