Migration and Transformation of Vanadium and Nickel in High Sulfur Petroleum Coke during Gasification Processes

The volatilization characteristics and occurrence forms of V and Ni in petroleum coke (petcoke) were investigated during steam (H 2 O) and carbon dioxide (CO 2 ) gasification on a fixed bed reactor at 800–1100 °C. The Tessier sequential chemical extraction procedure was employed to determine the different forms of V and Ni. The results showed their volatilities were not dependent on the gasification atmosphere, but rather relied mainly on the reaction temperature. The CO 2 atmosphere accelerated the conversion of organic-bound nickel to residual form at low temperature and promoted Fe-Mn oxides formation at high temperature. However, the H 2 O atmosphere was conducive to form vanadium bound to Fe-Mn oxides and promoted the decomposition of residual forms. In addition, the thermodynamic equilibrium calculations showed the volatilization of Ni mainly released Ni 3 S 2 between 800–1100 °C. The H 2 O atmosphere was favorable to generate the more stable Ni x S y compound, thereby suppressing the volatilization of Ni, while the presence of CO 2 led to an increase in residual V and decrease of Fe-Mn oxides. The V and Ni mainly caused erosion problems under the CO 2 atmosphere while the fouling and slagging obviously increased under the H 2 O atmosphere with impacts gradually weakened with the increase of temperature.