AIEWRACT-The pyrolysis of general biomass materials is modeled via a superposition of cellulose, hcmiccllulosc and lignin kinetics. All three of the primary biomass components arc modeled with multi-slcp kinetics involving both compcte-tivc primary pyrolysis and secondary tar decomposition reactions. Only " typical " (untreated) fccdstocks arc considered at at mosphcric pyrolysis pressures. The...

the present article serves the purpose of pursuing geometrization of heat flow on volumetrically isothermal manifold by means of rf approach. in this article, we have analyzed the evolution of heat equation in a 3-dimensional smooth isothermal manifold bearing characteristics of riemannian manifold and fundamental properties of thermodynamic systems. by making use of the notions of various curva...

This paper presents experimental observations of the nanocrystallization process in materials having Fe–Si (FINEMET), a-Fe (NANOPERM), and a0-FeCo (HITPERM) nanocrystals coupled through an amorphous phase. Crystallization kinetics and chemical partitioning during crystallization are described. Isothermal nanocrystallization is discussed in the framework of the Johnson–Mehl–Avrami–Kolmogorov mod...

Thermal decomposition kinetics of calcium carbonate was studied by non-isothermal thermogravimetric analysis at different heating rates. The reaction mechanism was found to follow a two-dimensional phase boundary-controlled model by modelfree and model-fitting methods. Two non-Arrhenius equations (Harcourt–Esson equation and Berthelot–Hood equation) were used to interpret the decomposition kine...

We have studied the interaction of polyaromatic hydrocarbons ~PAHs! with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene, and ovalene at submonolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV, and 2.1 eV, respectively. Benzene and naphthalene follow simple first order desorption kinetics while corone...

We extend Karma and Rappel's improved asymptotic analysis of the phase eld model to diierent diiusivities in solid and liquid. We consider both second-order \classical" asymp-totics, in which the interface thickness is taken much smaller than the capillary length, and the new \isothermal" asymptotics, in which the two lengths are considered comparable. In the rst case, if the phase eld model is...

Dehydration of methanol to dimethyl ether (DME) over a commercial Al2O3 catalyst was studied in an isothermal integral fixed bed reactor. The experiments were performed on the temperature interval 513-613 K, liquid hourly space velocity (LHSV) of 0.9-2.1h, pressures between 0.1 and 1.0 MPa. The effect of different operation conditions on the dehydration of methanol was investigated in a laborat...

We extend Karma and Rappel’s improved asymptotic analysis of the phase field model to different diffusivities in solid and liquid. We consider both second-order “classical” asymptotics, in which the interface thickness is taken much smaller than the capillary length, and the new “isothermal” asymptotics, in which the two lengths are considered comparable. In the first case, if the phase field m...

The nitration process of salicylic acid for the production of the important intermediate 5-nitrosalicylic acid is studied from thermokinetic and safety points of view. Investigations carried out by considering, as process deviations, the loss of the thermal control point out the possibility of runaway phenomena due to the occurrence of polynitration reactions. Isothermal experiments are carried...

This work investigates the crystallization kinetics and thermal stability of a new melt processable semicrystalline polyimide (Tg= ca. 210°C, Tm= ca. 395°C) based on 1,3bis(4-aminophenoxy) benzene (TPER) and 3,3’,4,4’-biphenyltetracarboxylic dianhydride (BPDA), and endcapped with phthalic anhydride (PA). Earlier studies have demonstrated that this polymer is a strong candidate as a structural a...