Biocrude Production from Hydrothermal Liquefaction of Chlorella: Thermodynamic Modelling and Reactor Design

Hydrothermal liquefaction can directly and efficiently convert wet biomass into biocrude with a high heating value. We developed a continuous hydrothermal liquefaction model via Aspen Plus to explore the effects of moisture content of Chlorella, reaction pressure and temperature on thermodynamic equilibrium yields, and energy recoveries of biocrude. We also compared the simulated biocrude yield and energy recoveries with experiment values in literature. Furthermore, vertical and horizontal transportation characteristics of insoluble solids in Chlorella were analyzed to determine the critical diameters that could avoid the plugging of the reactor at different flow rates. The results showed that the optimum moisture content, reaction pressure, and reaction temperature were 70–90 wt%, 20 MPa, and 250–350 °C, respectively. At a thermodynamic equilibrium state, the yield and the energy recovery of biocrude could be higher than 56 wt% and 96%, respectively. When the capacity of the hydrothermal liquefaction system changed from 100 to 1000 kg·h−1, the critical diameter of the reactor increased from 9 to 25 mm.

Prospects for producing hydrogen-ammonia fuel using lithium-aluminum amide

A statistical theory of the phase transformation of lithium aluminum amide with the release of ammonia is developed. The free energies of the phases are calculated, their dependence on temperature, pressure, hydrogen concentration and energy parameters is established. The phase diagram is built. The equations of the thermodynamic equilibrium state are calculated. Investigated isoprocesses in phases. The coefficients of rectangularity and uniformity of isotherms are obtained. A feature of the temperature dependence of the concentration of hydrogen in phases is established.

Self-Assembly of Microscopic Rods Due to Depletion Interaction

In this article, using numerical simulations we investigate the self-assembly of rod-like particles in suspension due to depletion forces which naturally emerge due to the presence of smaller spherical depletant particles. We characterize the type of clusters that are formed and the evolution of aggregation departing from a random initial configuration. We show that eventually the system reaches a thermodynamic equilibrium state in which the aggregates break and reform dynamically. We investigate the equilibrium state of aggregation, which exhibits a strong dependence on depletant concentration. In addition, we provide a simple thermodynamic model inspired on the theory of self-assembly of amphiphilic molecules which allows us to understand qualitatively the equilibrium aggregate size distributions that we obtain in simulation.

On the Question of the Problems of Statistical Calculations of the Conducting Crystals Thermodynamic and Kinetic Properties

This paper presents an elementary model of a crystal and its thermodynamic equilibrium state. It was shown that the thermodynamic characteristics of the crystal at this state are described by the Gibbs grand thermodynamic potential. If the crystal is removed away from the equilibrium state, then in this state it will be described by the set of kinetic properties, and these properties are statistically calculated with the use of the non-equilibrium Gibbs grand thermodynamic potential. Crystals’ thermodynamic and kinetic properties have analytical dependence on the current carriers dispersion law and chemical potential of these carriers. In this work, it was shown that the determination of the dispersion law and chemical potential – these are complicated problems of statistical and kinetic theories of crystals’ properties.

Numerical Simulation of Small Radius Polaron in a Chain with Random Perturbations

We consider the dynamics of polaron in a chain using computational experiment. The temperature, which is simulated by random Langevin-type perturbations, and influence of external electric field are taking into account. In a sufficiently long unperturbed chain, the displacement of the center of mass of the polaron and its velocity does not depend on its length. In the semiclassical Holstein model, which is applied for simulations of charge transfer in DNA, the region of polaron existence in the thermodynamic equilibrium state depends not only on temperature, but also on the chain length. Therefore, when modeling dynamics from polaron initial data, the time dependences of the average displacement of the charge mass center at the same temperature are different for chains of different lengths. According to the results of computational experiment, for polaron of large radius the time dependence of the “average polaron displacement”, which takes into account only the polaron peak and its position, for chains of different lengths behaves almost equally at time intervals until the polaron will destroyed. The same slope of the polaron displacement allows us to estimate the average polaron velocity. The results of calculations demonstrate that in Holstein model at zero temperature, the mobility value of the large radius polaron is small but non-zero.

Photo-induced translocation of a Pdn moiety (n = 2, 7) on a conjugated polyene ligand

The Pd2-translocation on a tetraene ligand is switchable between the thermodynamic equilibrium state and the photo-stationary state. The Pd7-translocation on a carotene ligand proceeds smoothly under photo-irradiation.

A two-step mechanism in nucleation of solid silica from Fe-O-Si melt

In order to control the structure and size distribution of silica inclusions in high purity steel, it is necessary to understand the nucleation mechanism of solid silica in molten steel. In high temperature reactions, crystallization begins with nucleation, which plays a crucial role in determining the structure and size of solid products. Nucleation originates in the formation of product intermediates. The structure and thermodynamic properties of silica clusters as the intermediate of solid silica products during nucleation were calculated by density functional theory. Comparison of thermodynamic properties of silica clusters and silicon deoxidation equilibrium experiment in liquid iron results shows the silica clusters with most of the dissolved silicon and oxygen in equilibrium; the molten iron silicon deoxidation reaction ([Si] [Formula: see text] [O] [Formula: see text] cannot reach thermodynamic equilibrium state, and some deoxidation products could only exist in the form of silica clusters but not the solid silica. Therefore, the nucleation process of solid silica in Fe-O-Si melt can be considered as a two-step process with silica clusters as intermediates. Finally, there are two paths of solid silica inclusion formation: one is that in the molten iron, the dissolved silicon reacts with the dissolved oxygen to form silica clusters, and clusters further nucleate and grow up; the second one is that silica clusters directly crystallized during the cooling process of the melt.

U- to Z-shape isomerization in a Pt2Ag2 framework containing pyridyl-NHC ligands

A highly twisted U-shaped Pt2Ag2 complex bearing pyridyl–NHC ligands showed isomerization to Z-shaped conformations via an intermolecular process. 1H NMR experiments revealed that the isomerization reached U : Z = 2 : 1 ratio in a thermodynamic equilibrium state.