Fischer–Tropsch Synthesis Over Cobalt Catalyst Supported On Hydrothermal Carbon Coating Titanium

The Fischer-Tropsch synthesis(FTS) enables a switch of coal, natural gas and biomass to ultra-clean transportation fuels and valuable chemicals, by which syngas can be catalytically converted into hydrocarbons by means of the hydrogenation of adsorbed CO on transition metals. The corresponding catalytic activity is considered to be depend on the number of available surface metal sites. In order to achieve high concentration surface active sites, the choice of appropriate support was the one of the most important aspects. In this work, carbon coating TiO2 materials was prepared by hydrothermal method, and used as support for cobalt-base catalyst, their catalytic performance in Fischer-Tropsch synthesis was investigated.Following three aspects were studied:(1) Preparation of hydrothermal carbon, silicon and alumina modified titanium dioxide materials, and investigation of catalytic performance of corresponding supported Co catalysts;(2) The effect of calcination temperature on the structure of hydrothermal carbon;(3) The influence of the thickness of hydrothermal carbon layer on the cobalt catalyst performance. The supports and catalysts were characterized by TEM, XRD, XPS, H2-TPR, etc. The catalytic performance of catalysts was tested on a fix-bed reactor. The major results are as follows:(1) Silicone introduction improved the reduction property of catalyst, while introduction of aluminum improved the dispersion of catalyst, both catalysts showed better catalytic performance than unpromoted counterpart.(2) Functional groups and branched-chain, like hydroxyl and carboxyl were introduced by the addition of hydrothermal carbon, which improved both the reduction and dispersion of cobalt species, and, thus the corresponding catalyst showed an enhanced catalytic performance.(3) The type of functional groups on the carbon layer and the carbon composition were changed by calcination process. The functional groups and carbon structure before calcination was more effective in improving the catalyst dispersion.(4) The thickness of carbon layer could change the interaction between cobalt and titanium, aand led to a diversity catalytic properties. The catalyst with carbon layer of 7nm thick had showed the best catalytic performance.