A study on the applicability of non-stoichiometric thermodynamic models for the prediction of carbon black yield and off-gas composition in oil furnace process

The effect of feed composition and temperature on the carbon black yield and off-gas amount and composition was studied for oil-furnace process reactor with benzene as a model feedstock. Because of the high furnace temperature (>1200 °C), the reactions were considered as very fast and thus the products close to chemical equilibrium. The equilibrium composition was calculated by a non-stoichiometric thermodynamic model using Gibbs free energy minimization method. The equilibrium and energy balance equations were solved simultaneously to obtain the product composition and reactor temperature under different reaction conditions. The equilibrium carbon black yield increases with gas/air and oil/air ratio whereas the reactor temperature exhibits the reverse trend which are consistent with practical data. Quantitative comparison with real data showed that the product may be kinetically controlled, and thus the thermodynamic model gives the lower limit of carbon black yield. The model can be easily applied to any feedstock including bio-oil without a need for the specific properties

NiO–MgO Solid Solution Prepared by Sol–Gel Method as Precursor for Ni/MgO Methane Dry Reforming Catalyst: Effect of Calcination Temperature on Catalytic Performance

International audienceThe influence of calcination temperature (500, 600 and 700 °C) on NiO–MgO solid solution formation and the performance of the resulting catalysts in CO2 reforming of methane was studied. The solid solutions and resulting catalysts were characterized by Brunauer–Emmett–Teller, XRD, temperature-programmed reduction (TPR), TEM and thermal gravimetric analysis techniques. Catalytic performance tests were carried out under 550–750 °C, 1 bar, CO2/CH4 = 1–3 mol/mol and space velocities of 30,000–120,000 ml/(h gcat). The catalyst calcined at 600 °C exhibited the best performance in terms of catalytic activity and stability and showed lowest amount of coke formation after 50 h-on-stream. The effect of calcination temperature on degree of NiO–MgO solid solution formation was demonstrated by both XRD and TPR profiles. The 600 °C calcination temperature was found to be an optimum as it caused modest NiO–MgO interaction, which is responsible for complete formation of the NiO–MgO solid solution with high nickel dispersion and resistant to coke formation