Exploring the pyrolysis of tar-rich coals under the catalysis of cerium-modified magnetic core-shell HZSM-5
[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 re-search and development of efficient and recyclable catalysts for the pyrolysis of tar-rich coals remains highly challen-ging.[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 modifica-tion,followed by the preparation of cerium-modified mHSMF(5-CeO2/mHSMF)using the precipitation method.Em-ploying 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℃in the N2 atmosphere for 1 hr using 5-CeO2/mHSMF as a catalyst,the coals exhibited a tar yield of 13.38%,equi-valent to a tar yield of 176%in the Gray-King assay.Compared to the pyrolysis of raw coals,the catalytic pyrolysis ex-hibited 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 en-hanced 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-car-bon deposition performance and magnetic recyclability.
tar-rich coalpyrolysismagnetic catalystcerium-based modificationanti-carbon depositionoil and gas quality improvement
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