Reactive Gas Flow Research Articles

Assessment of hyper-thermophilic/mesophilic temperature-phased anaerobic co-digestion of crude glycerine and sewage sludge

Temperature-phased anaerobic digestion is considered to be a valuable alternative to achieve new challenges in Wastewater Treatment Plants (WWTP) and biomethane production. This system makes it possible to remove/separate gas toxicants (mainly H2S) in the first phase reactor gas flow (hydrolysis reactor) and improve the profitability of the upgraded biogas flow obtained in the second phase reactor (methanogenic) (i.e. injection into the natural gas grid, vehicle fuel, biogas fuel cell or solid oxide fuel cell quality). The purpose of this study is to investigate the temperature-phased (hyper-thermophilic/mesophilic) anaerobic co-digestion of crude glycerine (CG) and sewage sludge (SS) in semi-continuous reactors. Specifically, to determine the effect of temperature-phased in: i) the quantity and quality of biogas production and ii) the effect on dewatering properties of the digestate obtained in comparison with conventional mesophilic systems. Results show that with a feed composed of 95% SS and 5% CG, the hyper-thermophilic/mesophilic system presents an increase in VSrem (Volatile solids removed) of 5.6% in comparison to the conventional mesophilic system. In reference to biogas quality, the hyper-thermophilic/mesophilic system presents a H2S content decrease of >67% in comparison to the control mesophilic reactor. Moreover, an energy balance shows that the proposed system reaches up to 68% extra heat production in comparison to the conventional mesophilic anaerobic system.

Conversion of glycerol to hydroxyacetone over Cu and Ni catalysts

The conversion of glycerol to hydroxyacetone, in gas phase and atmospheric pressure, was investigated over γ-Al2O3 and TiO2 supported copper and nickel catalysts. The catalysts were prepared by co-impregnation and pre-treated with hydrogen at 450 °C. It was studied eight different catalysts at 280 °C under nitrogen atmosphere. The higher glycerol conversion and selectivity to hydroxyacetone were obtained with the monometallic Cu/γ-Al2O3 and Cu/TiO2 catalysts. Furthermore, high selectivity to lactic acid was obtained over Cu/TiO2. These catalysts were characterized by XRD, SEM, EDS, TEM, N2-physisoption, and NH3-TPD. Furthermore, the Cu/γ-Al2O3 catalyst was studied on different reaction temperature and gas flow conditions. It was obtained that the selectivity to hydroxyacetone is favors at lower temperatures. However, the catalyst suffer deactivation. Carbonaceous deposits over the used sample were not revealed by Raman and FTIR. Finally, a regeneration treatment by oxidation–reduction reactivated the Cu/γ-Al2O3 catalyst successfully.

Effects of the Nitrogen Flow Ratio and Substrate Bias on the Mechanical Properties of W–N and W–Si–N Films

The reactive gas flow ratio and substrate bias voltage are crucial sputtering parameters for fabricating transition metal nitride films. In this study, W–N films were prepared using sputtering with nitrogen flow ratios (f) of 0.1–0.5. W–N and W–Si–N films were then prepared using an f level of 0.4 and substrate bias varying from 0 to −150 V by using sputtering and co-sputtering, respectively. The variations in phase structures, bonding characteristics, mechanical properties, and wear resistance of the W–N and W–Si–N films were investigated. The W–N films prepared with nitrogen flow ratios of 0.1–0.2, 0.3, and 0.4–0.5 displayed crystalline W, amorphous W–N, and crystalline W2N, respectively. The W–N films prepared using a nitrogen flow ratio of 0.4 and substrate bias voltages of −50 and −100 V exhibited favorable mechanical properties and high wear resistance. The mechanical properties of the amorphous W–Si–N films were not related to the magnitude of the substrate bias.

Effect of reactant gas flow orientation on the current and temperature distribution in self-heating polymer electrolyte fuel cells

Fuel cell polarisation performance is typically reported under controlled/constant temperature conditions, as a sign of robust metrology. However, in practice, fuel cells self-heat as they generate current; which varies the temperature across the polarisation curve and affects performance. More detail regarding the internal cell operation can be gleaned by current and temperature distribution mapping. For the case of an unheated cell, ‘self-heating’ increases the cell temperature and improves performance, resulting in a ‘voltage recovery’ and a more homogeneous current and water distribution. For actively heated cells, a reduced current is observed in regions of high temperature and low humidity.The positioning of the gas manifolds also has a decisive impact on performance by affecting the reactant concentration, humidity and water distribution. Counter- and cross-flow orientations in a self-heating cell were studied, with a counter-flow orientation with air flowing with gravity producing the most uniform temperature distribution.

Microwave-induced selective decomposition of cellulose: Computational and experimental mechanistic study

Understanding microwave-material interactions will help facilitate the utilization of microwave technology in gasification and renewable energy production. In this study, cellulose was used as a model compound to simulate the organic matter in biomass, and its catalytic decomposition under a microwave (MW) field was studied to identify structural changes from the reaction. The study was conducted using a MW source coupled to a fixed-bed gas-flow reactor, mass spectroscopic, and Fourier transform infrared spectroscopy post-reaction analysis. Zeolite 13X was chosen as a microwave absorber to study the catalytic enhancement of the decomposition of cellulose. Density functional theory (DFT) was used to gain insights into the molecular transformations occurring in the presence of a static electric field, which was used to simulate the electric field component of the microwave electromagnetic radiation providing a theoretical basis for molecular sites to be selectively heated. Theoretical calculations demonstrated that both the positive and negative portion of the electric field interact with the permanent dipoles of the cellulose leading to Debye-type loss processes and localized heating indicated by the decomposition through the glycosidic bond breaking mechanism. The theoretical result was verified using infrared spectroscopic analysis of the pure cellulose during microwave heating. The theoretical calculations help to elucidate the dipoles and molecular bonds in the cellulose structure, which are more sensitive to selectively localized heating as compared to other bonds and conventional heating. Physically mixing Zeolite 13X with the cellulose led to a significant enhancement in the decomposition rate of the glycosidic bond. Zeolite 13X enhanced the glycosidic O–C decomposition at lower MW power (lower temperatures), whereas the O–H functional group required higher MW power (higher temperature) for its decomposition. The DFT study coupled with the reaction studies revealed that the electric field polarizability, and subsequent, localized heating, is dependent upon both the direction and the orientation of the cellulose. Gas products revealed that applying 250 W of MW power led to the production of CO, H2, along with some CO2, CH4, and benzene at 305 °C. Reaction under 500, 750, and 1000 W of power at constant temperature (305 °C) revealed that higher power led to the complete decomposition of cellulose to mostly CO, H2, and CO2.

HI-Light: A Glass-Waveguide-Based "Shell-and-Tube" Photothermal Reactor Platform for Converting CO2 to Fuels.

SummaryIn this work, we introduce HI-Light, a surface-engineered glass-waveguide-based “shell-and-tube” type photothermal reactor which is both scalable in diameter and length. We examine the effect of temperature, light irradiation, and residence time on its photo-thermocatalytic performance for CO2 hydrogenation to form CO, with a cubic phase defect-laden indium oxide, In2O3-x(OH)y, catalyst. We demonstrate the light enhancement effect under a variety of reaction conditions. Notably, the light-on performance for the cubic nanocrystal photocatalyst exhibits a CO evolution rate at 15.40 mmol gcat−1 hr−1 at 300°C and atmospheric pressure. This is 20 times higher conversion rate per unit catalyst mass per unit time beyond previously reported In2O3-x(OH)y catalyst in the cubic form under comparable operation conditions and more than 5 times higher than that of its rhombohedral polymorph. This result underscores that improvement in photo-thermocatalytic reactor design enables uniform light distribution and better reactant/catalyst mixing, thus significantly improving catalyst utilization.

Electrochemical Pressure Impedance Spectroscopy As a Diagnostic Method for Hydrogen-Air Polymer Electrolyte Fuel Cells

This work introduces a novel in-situ diagnostic method for polymer electrolyte fuel cells (PEFCs) referred to as electrochemical pressure impedance spectroscopy (EPIS). Inspired by electrochemical impedance spectroscopy (EIS), EPIS is a spectroscopic technique that analyses correlations between frequencies in an applied pressure signal and the corresponding voltage response signal in the frequency domain. In EPIS, cathode cell pressure is modulated as a sinusoidal wave by the back-pressure controller (BPC), and the cell voltage is monitored as the response signal. Cell voltage response originates from the membrane electrode assembly (MEA) and, therefore, EPIS can be used to probe cathode transport properties and is sought to develop tools that can be used to study water transport as a function of changes in structure and operating conditions. The cathode reactant gas flows through channels with a pressure drop and, thus, the pressure signal is not identical in different sections of the flow channel. Before studying the relationships between pressure and voltage, it is important to consider the impact of the flow channel on oscillations in the pressure response. The response of the system as a function of correlations between the cathode inlet pressure and the cathode outlet pressure is examined in this work to probe the contributions of the flow channel. Due to instrumental limitations, the BPC can only perform tests at a frequency of 0.1 Hz. Experimental limitations like cathode stoichiometry ratio, cathode flow rate, oxygen partial pressure at cathode, and pressure oscillation amplitude are intensively studied, and therefore, EPIS experimental formalism is defined in this work. Figure 1

Effect of Gas Leakage on the Performance of Planar Solid Oxide Fuel Cells

Solid oxide fuel cell (SOFC) is a promising power source with its strong advantage being the use of solid oxide electrolyte. This allows long time operation of the cell without electrolyte depletion. Due to the solid nature of SOFCs, sealing of the cell to the peripheral attachments becomes an issue, especially in planar SOFC type. This defect in gas sealing causes gas-leakage to the outside, as well as, gas-crossover through the peripheral areas of the cell. These leakages lead to a reduction in the open-circuit voltage (OCV) and the overall cell performance. Most previous reports made on gas crossover were only based on H2 crossover through the thin electrolyte membrane. In this work, the performance of a gas-leaked cell was compared with one with a gas-tight sealing. Both cells were 100 cm2 planar SOFCs operated at 750 and supplied with H2 and air gases at the anode and cathode respectively. The cells were supplied by a commercial SOFC producer in South Korea. Electrochemical Impedance Spectroscopy (EIS) and steady-state polarization (SSP) techniques were used in comparing the performance of the cells. An inert gas step addition (ISA) method [1] was also employed in determining quantitatively the partial pressure of water formed at the anode and its resulting internal short current. The ISA was first used to investigate the flow and partial pressure effect on the performance of a molten carbonate fuel cell (MCFC). The method adds nitrogen gas to the anode gas flow and the addition simultaneously increases the reactant gas flow until the added nitrogen arrives at the cell. The nitrogen addition port is placed ca. 5 m ahead of the anode electrode and is supplied through a 1/4-inch stainless tube, thus several seconds are required by the N2 gas to reach the cell. The SSP behavior showed that the OCV and the polarization voltages recorded were higher in the gas-tight cell than in the gas-leaked cell. The impedance spectra, on the other hand, showed a remarkable decrease in the gas-leaked cell and was attributed to the decrease in the water-induced mass transfer resistance of the cell. Through the ISA method, the partial pressure of water formed at the anode as a result of the gas leak was quantitatively determined and was observed to be significantly higher in the case of the gas-leaked cell. Similarly, the computed internal short current was greater in the case of the gas-leaked cell.[1] C.-G. Lee, B.-S. Kang, H.-K. Seo, H.-C. Lim, J. Electroanal. Chem., 540, 169–188 (2003).

Rarefied reactive gas flow in T-shape microreactors

The present study investigates the reactive gas flows in T-shape microreactors by means of a 3D direct simulation Monte-Carlo method (DSMC). The reactive process is modeled by incorporating a single step irreversible exothermic reaction of gas species A and B. The energy released in each reaction is added to the system by increasing the kinetic energy of the product gas specie C. The reactive collisions are modeled by means of a momentum preserving hard sphere collision model in 3D DSMC. We analyzed several process and gas parameters to observe their extent of influence on the characteristics of the reactive flow. The T-microreactor with thermal walls showed much higher mass carrying capacity as compared to the specular walls. The reaction front, which initially for maximum reaction rate was close to the inlet of gas specie of higher mass density, moved towards the center of the inlet part of the T-channel and eventually dissolved with decreasing reaction rates. This transition was smooth in the T-channel with thermal walls, whereas, quite abrupt in case of specular walls. Moreover, in T-microreactors with thermal walls, the amount of A and B converted to C follows an exponential decrease especially in moderate to low reaction rates. Further, with a clear separation between high and low reactive regimes, a piece-wise exponential decay in concentration of C with respect to decreasing reaction rates was also observed in the T-channel with specular walls.

Multifunctional MoOx and MoOxNy films with 2.5 < x < 3.0 and y < 0.2 prepared using controlled reactive deep oscillation magnetron sputtering

Reactive deep oscillation magnetron sputtering with a pulsed reactive gas flow control and to-substrate reactive gas injection into the high-density plasma in front of the sputtered Mo target was used for a low-temperature (< 120 °C) preparation of MoOx and MoOxNy films with 2.5 < x < 3.0 and y < 0.2. We explain the advantages of this deposition technique, allowing us to control smoothly and reproducibly the film composition and thus the film structure and properties. Special attention is paid to the strong effect of slightly decreasing x in MoOx films and slightly increasing y in MoOxNy films on their optical and electrical properties which are directly related to varying electronic structure of the films. We discuss possible applications of these films in the field of solar cells, organic electronic devices and lithium-ion batteries.

Development of the Crank’s diffusion model for the case of material-gas feedback regime in gas flow reactors. Advanced methodology of oxygen partial pressure relaxation for the kinetics of oxygen exchange in nonstoichiometric oxides

• The Crank model may give incorrect k and D in case of vigorous reaction. • Extended samples require consideration of convective and diffusion gas transfer. • Models taking into account these factors are developed in this study. In order to determine the kinetic parameters of oxygen exchange between nonstoichiometric oxides and the gas phase, the rate constant of surface exchange k and the coefficient of bulk oxygen diffusion in the oxide D , one needs to model the kinetics of relaxation occurring under mixed diffusion-reaction control. It is shown that the widely used Crank model can misestimate the k and D values as it does not take into account such factors as (i) changes in oxygen partial pressure p O 2 in the reactor caused by vigorous reaction, (ii) the non-uniform distribution of p O 2 over the elongated oxide sample. Models taking into account these factors are discussed sequentially in this work: the ideal continuous stirred-tank reactor (CSTR) model where p O 2 varies over time as reaction proceeds; the tanks-in-series (TIS) model imitating the non-uniform distribution of p O 2 over the sample under approximation of convective gas transfer; and the model of tanks-in-series with diffusion-convective gas transfer (TSD). The TIS and TSD models (the latter one being used for low gas flow rates), which take into account all of the above factors, give the most reasonable results: the scatter of the values of the kinetic constants k and D determined at different rates of gas flow in the reactor does not exceed the reasonable experimental error. An expression is proposed for estimating k TIS , which corrects the k values obtained from the Crank model.

Sputtered ruthenium oxide coatings for neural stimulation and recording electrodes.

We have investigated the deposition and electrochemical properties of sputtered ruthenium oxide coatings for neural stimulation and recording electrodes. A combination of oxygen and water vapor was used as a reactive gas mixture during DC magnetron sputtering from a ruthenium metal target. The sputtering plasma was monitored by optical emission spectroscopy to determine the reactive species present and confirm the control of plasma chemistry by reactive gas flow rates into the deposition chamber. The effect of the O2 :H2 O gas ratio on the microstructure and electrochemical properties of the ruthenium oxide were studied in detail. We employed a combination of surface characterization techniques, including scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy, to understand the relationship between plasma chemistry and the microstructure of the films produced under different gas flow conditions. Electrochemical characterization included cyclic voltammetry, electrochemical impedance spectroscopy, and voltage transient measurements, performed on planar ruthenium oxide electrodes with a geometric surface area of 1960 μm2 . At an O2 :H2 O gas flow rate ratio of 1:3, a cathodal charge-storage capacity per unit film thickness of 228.7 mC cm-2 μm-1 (median, Q1 = 134.5, Q3 = 236.6, n = 15) and a charge-injection capacity (0.6 V anodal interpulse bias) of 7.4 mC cm-2 (median, Q1 = 6.9, Q3 = 8.3, n = 15) were obtained in phosphate buffered saline. The charge-injection capacity of ruthenium oxide sputtered with water vapor in the reactive plasma is comparable with sputtered iridium oxide (SIROF) and higher than reported values for porous TiN, a commonly employed high-surface area stimulation electrode coating.

One-step conversion of syngas to light olefins over bifunctional metal-zeolite catalyst

Light olefins (C2–C4) are fundamental building blocks for the manufacture of polymers, chemical intermediates, and solvents. In this work, we realized a composite catalyst, comprising MnxZry oxides and SAPO-34 zeolite, which can convert syngas (CO + H2) into light olefins. MnxZry oxide catalysts with different Mn/Zr molar ratios were facilely prepared using the coprecipitation method prior to physical mixing with SAPO-34 zeolite. The redox properties, surface morphology, electronic state, crystal structure, and chemical elemental composition of the catalysts were examined using H2-TPR, SEM, XPS, XRD, and EDS techniques, respectively. Tandem reactions involved activation of CO and subsequent hydrogenation over the metal oxide catalyst, producing methanol and dimethyl ether as the main reaction intermediates, which then migrated onto SAPO-34 zeolite for light olefins synthesis. Effects of temperature, pressure and reactant gas flow rate on CO conversion and light olefins selectivity were investigated in detail. The Mn1Zr2/SAPO-34 catalyst (Mn/Zr ratio of 1:2) attained a CO conversion of 10.8% and light olefins selectivity of 60.7%, at an optimized temperature, pressure and GHSV of 380 °C, 3 MPa and 3000 h−1 respectively. These findings open avenues to exploit other metal oxides with CO activation capabilities for a more efficient syngas conversion and product selectivity.

Modeling of Detonation Processes in Propulsion Engine

Numerical modeling of chemically reacting gas flow in the propulsion chamber using theNavier-Stokes equations has been performed. The simplest form of the chamber has been used, when thelast one represents axially symmetrical plane disk. Fuel and oxidant were fed into the chamber separatelywith outflow to the periphery. The directions of fuel and oxidizer jets are not at right angles to the inflowsurface and not parallel one to another to supply better mixing of species. The detonation triggeringdepends on the values of angles between fuel and oxidizer jets. At parallel directions of the jetssignificant part of not reacted gas components leaves the chamber. This type of the propulsion chamber ismore effective than one studied before, because of absence of stagnation zones and good mixing ofspecies before burning. The diameter of the chamber may be done less, since the largest part of fuelreacted at the inlet surface.

Effects of substrate temperature and reactive gas flow rate on the crystalline ceramic phases formation and tribological properties of W–Ti–Co–C–N thin films produced by co-sputtering

The present study investigates the deposition condition of W–Ti–Co–C–N thin films made by magnetron co-sputtering. The central composite design of experiments was applied for analyzing the effect of substrate temperature (X1) and nitrogen gas flow rate (X2) on the mechanical properties. Nanoindentation, sliding wear test (ball-on-disk method), scanning electron microscopy, atomic force microscopy, and X-ray diffraction techniques were employed to evaluate the tribological properties and microstructure of the thin films. The optimum values of variables were found to be in the range of 500 °C < X1 and 6.5 < X2 < 9 sccm, giving a high hardness of 36.5 GPa, while the friction coefficient and wear rate have the lowest amount of 0.10 and 4 × 10−8 mm3/N.m, respectively.

Catalytic flow with a coupled finite difference — Lattice Boltzmann scheme

Many catalyst devices employ flow through porous structures, which leads to a complex macroscopic mass and heat transport. To unravel the detailed dynamics of the reactive gas flow, we present an all-encompassing model, consisting of thermal lattice Boltzmann model by Kang et al., used to solve the heat and mass transport in the gas domain, coupled to a finite differences solver for the heat equation in the solid via thermal reactive boundary conditions for a consistent treatment of the reaction enthalpy. The chemical surface reactions are incorporated in a flexible fashion through flux boundary conditions at the gas–solid interface. We scrutinize the thermal FD-LBM by benchmarking the macroscopic transport in the gas domain as well as conservation of the enthalpy across the solid–gas interface. We exemplify the applicability of our model by simulating the reactive gas flow through a microporous material catalyzing the so-called water-gas-shift reaction.

Relative oxidation state of the target as guideline for depositing optical quality RF reactive magnetron sputtered Al2O3 layers

Amorphous Al2O3 is an attractive material for integrated photonics. Its low losses from the UV till the mid-IR together with the possibility of doping with different rare-earth ions permits the realization of active and passive functionalities in the same chip at the wafer level. In this work, the influence of reactive gas flow during deposition on the optical (i.e., refractive index and propagation losses) and material (i.e., structure of the layer) characteristics of the RF reactive sputtered Al2O3 layers is investigated and a method based on the oxidation state of the sputtering target is proposed to reproducibly achieve low loss optical guiding layers despite the continuous variation of the condition of the target along its lifetime.

Study of (Ti,Zr)C:H/a-C:H nanocomposite thin film formation by low temperature reactive high power impulse magnetron sputtering

Single-phase nanocrystalline hydrogen-containing titanium zirconium carbide thin films and hydrogen-containing nanocomposite thin films consisting of a nanocrystalline hydrogen-containing titanium zirconium carbide phase in combination with an amorphous hydrogen-containing carbon network, (Ti1-xZrx)C1-δ:H/a-C:H, were deposited by low temperature reactive high power impulse magnetron sputtering (HiPIMS) in a methane-argon atmosphere. High power impulse magnetron sputtering offers a high degree of ionization of sputtered particles and therefore a precise control of the thin film growth. The thin film deposition in the Ti-Zr-C-H system was carried out by a combinatorial approach via the variation of both the titanium-to-zirconium ratio as well as the carbon and hydrogen content in the coatings. A single, metallic, segmented target consisting of two triangles of pure titanium and zirconium enabled the deposition of thin films with different titanium-to‑zirconium-ratio dependent of the substrate position in front of the target within one deposition process. By variation of the CH4 reactive gas flow at a constant Argon gas flow the carbon and hydrogen content of individual thin films was precisely adjusted. During the HiPIMS process a short pulse time of 50 μs was combined with a comparably low duty cycle of 3.3% in order to ensure a high ionization. In order to investigate the chemical composition of the thin films including hydrogen content electron probe microanalysis was combined in a self-consistent way with elastic recoil detection analysis. Structural analysis was done by a combination of different techniques: Raman spectroscopy suggests metal‑carbon bonds attributable to a nanocrystalline metal carbide phase as well as the formation of an amorphous hydrogen-containing carbon network. X-ray diffraction shows fcc (Ti1-xZrx)C1-δ:H grains with different sizes in all coatings. Transmission electron microscopy confirms the structure model of single phase nanocrystalline (Ti1-xZrx)C1-δ:H grains embedded in a hydrogen-containing amorphous carbon matrix. Scope of this work is the low temperature deposition of the (Ti,Zr)C1-δ:H thin films and the (Ti,Zr)C1-δ:H/a-C:H nanocomposites by HiPIMS with precise control of the resulting chemical composition and microstructure.

Iridium oxide top electrodes for piezo- and pyroelectric performance enhancements in lead zirconate titanate thin-film devices

Iridium oxide films of various morphologies are produced by manipulating the reactive gas flow rate in a reactive sputtering process. This study explores the benefits of using planar and nanostructured IrOx top electrodes for Pb(Zr0.52Ti0.48)O3 (PZT) devices employed in piezoelectric and pyroelectric applications in comparison with conventional platinum electrodes. For the first time, the Young’s modulus of a planar IrOx thin film was directly measured to be 300 ± 15 GPa. The piezoelectric performance of devices with planar IrOx showed up to 245% more strain compared to those capped with a Pt electrode. Nanostructured, 2D IrOx platelet networks are observed for films deposited with high oxygen flow rates. The compatibility with various cleanroom processes, such as liftoff, ultrasonic cleaning, and deposition on etched surfaces, is tested for the IrOx nanostructured layers. These films are shown to have low optical reflectivity while retaining good PZT thin-film capacitor polarization and dielectric permittivity. An improved pyroelectric energy harvesting figure of merit by a factor of 2.5× was observed for the IrOx compared to Pt films on the same PZT material.

Comparison of the Efficiency of the Reactors for Low-Temperature Pyrolysis of Biomass

Results from the comparative analysis of the energy and economic efficiencies of the torrefaction reactors (or low-temperature pyrolysis reactors) with the heat of the heating gas supplied directly to the processed biomass are presented. Upright reactors of two types are considered, viz., reactors with a bed of dense biomass moving by gravity towards the heating gas flow and fluidized-bed reactors. Advantages and drawbacks of the different types of torrefaction reactors are discussed. Criteria for the evaluation of the torrefaction reactors' energy efficiency have been defined based on the data of experimental research conducted on a pilot power-engineering plant at the Joint Institute for High Temperatures, Russian Academy of Sciences, equipped with a moving-bed reactor and the results of numerical modeling of a fluidized-bed reactor. The conditions for creating the thermal effect of the hemicellulose decomposition reaction and the mechanism that restricts the increase in the biomass temperature during the self-heating by the exothermic reaction heat are considered. The analysis performed has shown that a moving-bed reactor with a controlled exothermic biomass destruction reaction has the highest energy efficiency and the best criteria for estimating the financial and commercial efficiency of the investments. Conclusions have been made that moving-bed reactors are preferable for small-scale production for which granulated biomass (biomass pellets) is the optimal feedstock, while fluidized-bed reactors and fine-dispersed feedstock materials are more suitable for large-scale production.