不同催化剂上有机质加氢热解行为及催化作用机理研究

Performance of various catalysts in hydropyrolysis of organic matters and reaction mechanisms

对不同类型催化剂如Zn Cl2、Ni Cl2、Fe2O3、Y型沸石(Na Y)及Mo S2上有机质的催化加氢热解行为及反应机理进行了研究。结果表明,有机质加氢液态产物收率和组成受控于催化剂类型,但不同催化剂上加氢热解所得到的产物生标参数差异不大;同时,对于不同成熟度和类型的有机质样品,各催化剂所体现的催化效果也不尽相同。基于固体残渣元素组成、红外光谱和X射线衍射分析结果发现,不同类型催化剂上的加氢作用机制也存在明显差异。与Ni Cl2相比,Zn Cl2体系中除存在催化裂解和催化加氢作用外,还存在质量传递效应;Fe2O3催化剂主要是通过其表面的活性O吸收H2中的H形成H自由基而加速有机质的加氢反应;Mo S2体系存在过渡金属Mo的催化加氢和中间产物H2S的自由基引发作用两种催化机制。

The hydropyrolysis of organic matters was comparatively conducted over various catalysts including ZnCl_2,NiCl_2, Fe_2O_3, Na Y and MoS_2 and the reaction mechanisms over different catalysts were then investigated. The results indicate that the yield and composition of liquid products from hydropyrolysis are related to the type of catalyst,though various catalysts do not have significant difference in the product biomarker parameters. Meanwhile,for the organic matters with different maturities and types,various catalysts are also quite different in their actual performance. The element analysis,infrared spectra and X-ray diffractograms of the solid residues illustrate that various catalysts are obviously different in the catalytic reaction mechanism. In comparison with NiCl_2,mass transfer is an important factor in the ZnCl_2 system,besides the catalytic cracking and catalytic hydrogenation. With Fe_2O_3 as the catalyst,the formation of H free radical by the adsorption of H_2 at the surface active O sites may promote the hydrogenation of organic matters. MoS_2 as the catalyst may involve two mechanisms,viz.,the hydrogenation over transition metal Mo and the initiation of free radicals from H_2S intermediates.