Mesoporous Adsorbents for Desulfurization of Model Diesel Fuel: Optimization, Kinetic, and Thermodynamic Studies

Mesoporous alumina-based adsorbents consisting of a π-electron acceptor complexing agent (2,7-dinitro-9-fluorenone) were synthesized and characterized. Adsorbents were screened for the removal of sulfur compounds from a model ultra-low-sulfur diesel fuel via a charge transfer complex (CTC) mechanism. The sulfur adsorption isotherms and kinetics were examined. The kinetics of sulfur adsorption followed a pseudo-second-order model with the CTC adsorbents. Among the three adsorbents screened, a commercial γ-Al2O3 CTC adsorbent showed the highest desulfurization in a short-run period. The regeneration of spent adsorbent was studied with three different polar solvents, namely chloroform, dichloromethane, and carbon tetrachloride. Dichloromethane was found to be the most suitable solvent for extracting a major portion of sulfur compounds occupied in the pores of the spent adsorbent. γ-Al2O3 CTC adsorbent can be reused after regeneration. Thermodynamic parameters such as Ea, ΔG, ΔH, and ΔS provided a better insight into the adsorption process.

Thermal Degradation of Different Biomass to Fuel: Optimization of Process Parameters by Response Surface Methodology

In the present study, the yield of different pyrolysis products was optimized using Response Surface Methodology (RSM). Here, User Defined Model and quadratic programming (QP) have been used to model and optimize the influence of two process parameters like reaction temperature and type of biomasses on the five responses such as oil yield, liquid yield, char yield, gas yield and reaction time using the experimental data obtained from the fast pyrolysis in a semi-batch reactor system. Mathematical model equations are derived for all the responses by using sets of experimental data and analysis of variance (ANOVA). ANOVA analysis showed that the model was very significant for all the responses. From the residual vs. predicted plots, the value of the coefficient of correlation (R2) is found to be a good agreement with the experimental ones. From the optimization study, the liquid, oil, char, and gas yield at the optimum temperature (584C) of seed biomass are found to be 81.34%, 70.12%, 9.8%, and 9.64% respectively.

Nonlinear Trajectory Controller with Improved Performances for Waveriders

This paper presents a nonlinear trajectory controller with improved performances for a general model of the waverider based on feedback linearization theory and composite nonlinear feedback (CNF) technique. First, a nonlinear controller is presented using the dynamic inversion and CNF technique for the MIMO Model, and the robust stability of the proposed controller is proved. Then, the nonlinear model is established on the basis of hypersonic aerodynamic principle, and the dynamic characteristics are analyzed accordingly, and the periodic trajectory is designed and optimized in combination with a fuel optimization problem. Furthermore, the nonlinear controller is applied to the trajectory tracking of the waverider model, and the general design steps are provided the flight controller using this nonlinear control method. Finally, an illustrative example is given to verify the effectiveness of the nonlinear controller of the waverider, and the flight performances are improved accordingly, including system stability, robustness, and tracking ability.