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Heat transfer occurs due to the difference in temperature between the system and its surroundings. The effect of temperature can affect various aspects of the refining process, including efficiency, selectivity, reaction kinetics, and the quality of the final product. This study aims to analyze heat transfer in a double-jacket reactor by measuring temperature data taken using a temperature data logger system. Prototype low cost-effective temperature monitoring for double jacket reactor vacuum is this system integrates an Arduino Mega 2560, a type K thermocouple, amplifier MAX 6675 module, and an SD card data logger to measure and record reactor temperature for 30 minutes. The temperature data obtained is used to calculate the heat transfer and analyze the heat transfer characteristics of the reactor. Heat transfer analysis based on measured temperature data is able to provide insight into the characteristics of heat transfer in the observed system and can identify hot spots and heat transfer energy in the system. Thus, the temperature data logger used in the double jacket reactor in the vacuum distillation system can produce accurate data and information, and this system has broad application potential in temperature monitoring in various fields. [ABSTRACT FROM AUTHOR]

During the inactivation of various organic wastes by conventional thermal methods (distillation, desorption), the process temperature is lower than 1300-15000 C. However, this is not sufficient for proper decomposition of waste materials. For the complete decomposition of such materials, the reaction temperature should be raised to 18000 C. This article aims to determine the temperature and velocity profile distributions of the high-temperature gas flow inside the plasma reactor. According to the study, the plasma-chemical method for decomposition of sewage sludge is quite effective. The efficiency of the gas-phase sludge decomposition depends on the plasma flow parameters (temperature, velocity, etc.).

It is shown that a rotary vortex thermal unit can be used in order to produce a high quality gypsum binder (fast-setting A grade gypsum) including the utilization of gypsum-containing wastes taken from gas cleaning facilities, with obtaining a marketable product and reducing the accumulation of solid wastes, which should promote solving economic and environmental problems. By varying the maximum roasting temperature and the holding time, controlling both the binding properties of gypsum and its strength has been achieved. These properties are inversely related: as the roasting temperature increases, the binding properties get improved, whereas the strength of the hardened mortar exhibit a decrease. Increasing high-temperature exposure time, on the contrary, leads to worsening gypsum binding properties and improving gypsum strength properties. [ABSTRACT FROM AUTHOR]

The effective evacuation and separation (at helium temperature) of a model gas mixture consisting of He, H2, D2, N2, Ar and other components (close to that formed in a thermonuclear reactor) yielding up to 44% of D2 during desorption, is implemented using a newly developed vacuum pump-separator with a non-isothermal multilayer (up to 100 layers) system of working elements (consisting of perforated screening and spacing materials). Improvements to the vacuum-pump separator design and the use of an ortho-para conversion catalyst made it possible to increase the yield of D2 from the model mixture to 64–69% at hydrogen temperature. [ABSTRACT FROM AUTHOR]

To purify hydrogen gas from synthesis gas using a adsorption process, SAPO 34 adsorbent was used. Due to the strong adsorption of carbon dioxide in this adsorbent, it is not possible to recover the adsorbent by reducing the pressure alone, and it is necessary to use thermal operations for recovery. For this purpose, a temperature swing adsorption (TSA) process is used to increase the purity of hydrogen for use in fuel cells. To investigate the optimum operational conditions, various temperatures and different pressures of input gas were investigated to compare the purity and recovery of adsorption process. The TSA process was simulated for pressures of 11, 22 and 33 bars and the recovery percentage of each process was calculated. According to the results obtained, the recovery value at 33 bars is better than the other two pressures, but due to the fact that operational and initial costs increase at high pressures; 22 bar pressure was chosen to present the remaining results. In this work, the total amount of material and the molar rate are also reported. The average purity of the components in the product and waste outlet streams has also been presented. Accordingly, the average molar fraction of hydrogen in the product outlet stream is 99.96% in the temperature increase stage, 99.94% and in the stream used for temperature reduction is 99.96%. [Display omitted] • Design a adsorption process for hydrogen purification. • Using SAPO 34 as adsorbent for hydrogen purification. • Using PTSA (Pressure Temperature Swing Adsorption) for hydrogen purification. [ABSTRACT FROM AUTHOR]

Advanced core materials and components for nuclear reactors of a new generation are tested in the BOR-60 reactor. A novel irradiation rig (IR) with a fuel heater is used for high-temperature tests of material samples. The irradiation rig features a number of advantages over ampoule-type irradiation rigs commonly used nowadays. Computational and experimental studies on an IR with a fuel heater have been conducted in the BOR-60 reactor core. The results of a dedicated methodical experiment have proved that it is possible to provide the required temperature conditions for irradiation of tested samples. MCU-RR, a precision code, was used for neutronic calculations, and thermohydraulic calculations were performed using the ANSYS CFX software system. A comparison of calculated temperature values against experimental data has shown a fit in the experimental error limits which confirms the applicability of the selected codes, models and procedures. Computational and experimental studies have also been conducted for the temperature distribution in the IR with a fuel heater following the withdrawal of the IR from the reactor and its placement in a dry cooling channel. The decay power in the IR fuel pins were calculated using the AFPA code and the temperature fields were calculated based on ANSYS CFX. It has been shown that the permissible temperature value on the fuel cladding is not exceeded in the IR withdrawn from the reactor following two-day cooling after the reactor shutdown.

Summary: The progress of bio‐hydrogen technology has led to the development of new energy technologies and is significant for the sustainable use of energy. After summarizing current research results, this study discusses that the key to increasing the hydrogen production rate is to improve the activity of hydrogen producing bacteria under the conditions of anaerobic fermentation. Using waste to prepare hydrogen producing bacteria is the developmental trend. The primary factors influencing bio‐hydrogen production from plant straw fermentation are also pointed out, indicating the method to improve the hydrogen production rate from plant straw. In addition, application of artificial intelligence technology to a bio‐hydrogen production reactor is helpful to achieve automatic control of continuous bio‐hydrogen production and improve the rate of hydrogen production. [ABSTRACT FROM AUTHOR]

Questions related to modeling of physicochemical processes in the interaction of sulfurous shale with an ash-based heat-transfer agent under low-temperature carbonization conditions in a drum reactor with solid (ash-based) heat-transfer agent are considered. Combustible gas, resinous substances, and semicoke are the basic products of low-temperature carbonization. Through use of these products, it is possible to expand the raw material base of enterprises in the chemical, energy, and construction industries. The results in the article are illustrated by concrete numerical calculations and are complemented with an analysis of the results obtained. [ABSTRACT FROM AUTHOR]

Biomass pyrolysis is usually characterized on the basis of temperature and heating rate. Unfortunately, these parameters are badly defined in processing reactors as well as in laboratory devices. From the results of simplified models, the present paper points out the significant mistakes that can be made when assuming that the actual temperature and heating rate of reacting biomass particles are the same as those of the external heating medium. The difficulties in defining these two parameters are underlined in both cases of a heat source temperature supposed to be constant or to increase with time.

Analysis of the thermal state of molten pools that can be formed on the vessel bottom of the VVER-600 medium-power reactor during a severe anticipated accident with melting of the core is represented. Two types of the molten pool of core materials, with the two-layer and inverse three-layer stratification, are considered. Thermal loads acting on the reactor vessel from the melt are estimated depending on its formation time. Features of the thermal state of the melt in the case of its inverse stratification are analyzed. It is shown that thermal loads on the reactor vessel exceed the critical heat flux (CHF) when forming the two-layer stratified molten pool 10 and 24 h after its shutdown, and the thermal load is close to the corresponding CHF or somewhat exceeds it in 72 h. In the case of the formation of the inverse structure of the melt, one can observe a decrease by more than 2.5 times (in comparison with the two-layer stratified structure) in the thermal load on the reactor vessel in the region of its contact with the upper layer of the steel melt. Analysis of results showed that maximum densities of heat flux to the reactor vessel from the bottom metallic layer with the melt inversion did not exceed corresponding CHFs 24 and 72 h after the reactor shutdown. Because the thermal load on the reactor vessel can be localized in the region of its bottom, where the CHF is relatively small, during the inverse stratification of the melt, there is a need to carry out further in-depth experimental and analytical investigations of conditions for formation of the stratified molten pool and to obtain corrected experimental CHFs for conditions and outlines of cooling the external surface of the VVER-600 vessel in a severe accident. [ABSTRACT FROM AUTHOR]

The knowledge of the reactor thermal power calibration is important for neutron flux and burn-up determination. Burn-up is linearly dependent on the thermal power of the reactor and its accuracy is crucial for the determination of the mass of burned 235 U, fission products and decay heat power generation. Power monitoring of reactors is done by means of nuclear instrumentation, but its calibration is always done by thermal procedures. The aim of this paper is to present the result of the thermal power calibration of Nigeria Research Reactor-1 (NIRR-1), a low power Miniature Neutron Source Reactor (MNSR). In order to cover the whole range of the reactor, the calibration was performed at three different power levels: low power (3.6 kW), half power (15 kW) and full power (30 kW). The method used in the calibration involved the steady state energy balance of the cooling loop of the reactor. For this method, the measurement of the inlet temperature, outlet temperature and temperature difference were carried out and also flow-rate of the coolant passing through the core was determined. The heat losses by (conduction, convection and evaporation) were evaluated and the values added to the power calculated as a function of flow rate and temperature difference gives the total thermal power. In a quest to fully understand the behavior of the reactor and ascertain its maximum operable time, a special cadmium string of 1.16 mk inserted during commissioning into one of the inner irradiation channels, was removed and the reactor operated at full power in this condition. The thermal power dissipated in the core during this test period was also computed. The values of the thermal power obtained at low, half, full power and when the cadmium string was removed were: (3.7 ± 0.3) kW, (15.2 ± 1.2) kW, (30.7 ± 2.5) kW and (31.3 ± 8.2) kW respectively. Comparing the results obtained with NIRR-1 flux parameters and preset power on the console, it was observed that calibration at lower power yielded more accurate result with a deviation of only 6.8%. [ABSTRACT FROM AUTHOR]

The possibility of using the Star CCM+ software system for analyzing the thermal state of the melt pool metal layer generated as a result of melt stratification during a severe accident in pressure-vessel nuclear reactors is considered. In order to verify and substantiate the possibility of using this software system for modeling the natural convection processes in the melt at high values of the Rayleigh number, test problems were solved. The obtained results were found to be in good agreement with the known solutions and with the experimental data. The behavior of the melt metal layer was subjected to a parametric analysis for different melt heating conditions, the results of which showed that certain parameters have a determining influence on the so-called focusing effect and on the specific features of current in this layer. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the temperature distribution in the reactor of a plastics pyrolysis process from waste bottles of beverage to produce fuel. This process is considered an alternative technology to replace fossil fuel. This experiment was conducted using a cylindrical reactor, which has dimension of 0.31 m in diameter and 1 m high. In order to understand the temperature distribution in the reactor, five thermocouples were placed to measure temperature at the bottom and the top of the reactor as well as in the middle, with the different position of each thermocouple of 0.19 m respectively. The temperature outside the reactor and outside the condenser was also measured. Data Acquisition recorded all temperature data. The reactor was used to process 1,500 g plastics. The Computational Fluid Dynamic (CFD) was also used to know the contour of temperature inside the reactor. The result showed that to increase temperature from the ambient temperature to 450 o C, 72 minutes of time were needed. The lowest temperature of 310 °C was measured at the top of the reactor, whereas different temperature in the middle of the reactor was found to be 46 °C respectively. The pyrolysis process of 1,500 g plastics was completed in 110 minutes to produce 21 g of fuel. This fact shows that the pyrolysis process of plastics can produce fuel at 450 o C in the reactor and 75 o C outside the reactor. [ABSTRACT FROM AUTHOR]

The mesoscale oscillatory baffled reactor (meso-OBR) is a novel technology for reaction engineering and screening applications. The meso-OBR exhibits high degrees of plug flow at low and moderate net flow rates (0.3–8 mL/min). For example, central and integral baffle configurations give good plug flow at net flows of Re n = 4.3–34 for ψ = 4–8 and ψ = 5–10, respectively using St = 0.4–0.8. Recently, the batch equivalency of plug flow has been exploited to screen multiple equivalent batch reactions in a single experiment, minimising waste generation and reducing process development time. In addition, good multiphase mixing has been demonstrated using a variety of baffle configurations, presenting a wide range of potential applications for the technology. In this review, the characteristics of the mesoreactor that are beneficial for rapid process screening are explained. The results of all public domain reports of the use of mesoscale OBRs for screening are reported and the outlook for the technology is discussed. Throughout, the technology is compared and contrasted with the findings for “conventional scale” (>15 mm diameter) OBRs. A variety of case studies are used for illustrative purposes. [ABSTRACT FROM AUTHOR]

This paper studies the packaging pasteurization process with a reactor to determine its static and dynamic model before the control action. The reactor is used to pasteurize packages and canned, and the models are obtained with experimental statically and dynamically data and they were acquired to ambient temperature between 15°C and 35°C. Furthermore, the identification of a system consists in determining its transfer function or its basic parameters from experimental measurements [1]. There are currently a lot of different design methods that let to develop models of systems in a wide range of features and possibilities. Therefore, to determine, even approximately, the most important parameters of a transfer function of a system become an inescapable necessity, subsequently allow modeling a good model of a control system. Essential tools such as Matlab and Simulink allow simulating the system with reactor and tuning its parameters to achieve accuracy and precision in the expected response of the system. [ABSTRACT FROM AUTHOR]

Abstract: The presence of pathogenic free-living amoebae (FLA) such as Naegleria fowleri in freshwater environments is a potential public health risk. Although its occurrence in various water sources has been well reported, its presence and associated factors in biofilm remain unknown. In this study, the density of N. fowleri in biofilms spontaneously growing on glass slides fed by raw freshwater were followed at 32 °C and 42 °C for 45 days. The biofilms were collected with their substrata and characterized for their structure, numbered for their bacterial density, thermophilic free-living amoebae, and pathogenic N. fowleri. The cell density of N. fowleri within the biofilms was significantly affected both by the temperature and the nutrient level (bacteria/amoeba ratio). At 32 °C, the density remained constantly low (1–10 N. fowleri/cm2) indicating that the amoebae were in a survival state, whereas at 42 °C the density reached 30–900 N. fowleri/cm2 indicating an active growth phase. The nutrient level, as well, strongly affected the apparent specific growth rate (μ) of N. fowleri in the range of 0.03–0.23 h−1. At 42 °C a hyperbolic relationship was found between μ and the bacteria/amoeba ratio. A ratio of 106 to 107 bacteria/amoeba was needed to approach the apparent μ max value (0.23 h−1). Data analysis also showed that a threshold for the nutrient level of close to 104 bacteria/amoeba is needed to detect the growth of N. fowleri in freshwater biofilm. This study emphasizes the important role of the temperature and bacteria as prey to promote not only the growth of N. fowleri, but also its survival. [Copyright &y& Elsevier]

Abstract: A combined catalytic reactor and water absorber system has been applied in the field of nuclear fusion to control the tritium release into the environment as low as reasonably achievable. Efficient tritium oxidation performance at room temperature has been strongly required taking a severe accident in a facility into consideration. We have developed hydrophobic Pt catalysts applicable for tritium oxidation in the presence of saturated water vapor at room temperature. A new type of hydrophobic catalyst, Pt/ASDBC, has been prepared by dipositting platinum on alkyl-styrene diviyl-benzene copolymer (ASDBC). Tritium oxidation tests of the catalysts using 3GBq/m3 of tritium were performed in the absence/presence of saturated water vapor at room temperature. The overall reaction rate constant for Pt/ASDBC catalyst in the ambient temperature range was considerably larger than that for the traditionally applied Pt/Al2O3 catalyst. Oxidation reaction on the catalyst surface is the rate-controlling step in the ambient temperature range. The overall reaction rate constant in the ambient temperature range was dependent on the space velocity and hydrogen concentration in carrier. Values of the overall reaction rate constant in the ambient temperature range were correlated to k overall =1.60×105exp(−33.0 (kJ/mol)/R g/T) (s−1) at the space velocity of 5556h−1 under the dry condition. [Copyright &y& Elsevier]

Abstract: The objective of this investigation is to examine the impact of the fuel type on the inherent safety characteristics of Liquid Metal Fast Reactors (LMFRs). To perform this study, the responses to various transient conditions are examined for metallic, oxide and nitride cores of a baseline LMFR. GE-Hitachi’s Super Power Reactor Innovative Small Module (S-PRISM) was chosen as the baseline LMFR. In Part I of this paper, the background on S-PRISM’s metal and oxide cores are described and the redesign of a new nitride fueled S-PRISM core were introduced. Reactivity feedback and power profile data necessary for transient simulations with RELAP5-3D/ATHENA () code are also presented and discussed. In this Part II of our paper, we present the results of accident simulations and a comparison between the metal, oxide and nitride cores based on their performance during the selected accident scenarios. Loss of Flow, Loss of Heat Sink, Loss of Power and inadvertent control rod withdrawal accidents were simulated for each core at beginning (BOC), middle (MOC) and end of a fuel cycle (EOC). The simulations were stopped at the initiation of melting of fuel or cladding. The results showed that in most of the transients the metal core came closer to its melting temperature while the strong reactivity feedbacks of the oxide and nitride cores limited their fuel temperature increases. Overall, the oxide and nitride cores had similar performance with respect to their inherent safety characteristics. [Copyright &y& Elsevier]

Abstract: Gd-loaded liquid scintillators are promising tools for detection of anti-electron neutrinos, yet their stability remains a concern for neutrino experiments. This study investigated the instability of a Gd-loaded liquid scintillator and found that Gd precipitated and light yield decreased due to oxidation. The precipitation not only reduced transmission but also decreased the Gd concentration. However, when the antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT) was added to the liquid scintillator, we obtained a stable liquid scintillator at room temperature. [ABSTRACT FROM AUTHOR]

Biomass pyrolysis is usually characterized on the basis of temperature and heating rate. Unfortunately, these parameters are badly defined in processing reactors as well as in laboratory devices. From the results of simplified models, the present paper points out the significant mistakes that can be made when assuming that the actual temperature and heating rate of reacting biomass particles are the same as those of the external heating medium. The difficulties in defining these two parameters are underlined in both cases of a heat source temperature supposed to be constant or to increase with time. [ABSTRACT FROM AUTHOR]

Advanced control is used to avoid large temperature offsets for a batch copolymerization gas phase reactor. A nonlinear state-space model is developed to represent the reactor behavior in terms of mass and energy balances. A growth model describes the gas phase copolymerization and includes an activation–deactivation model for the catalyst. The control system includes three manipulated inputs, three controlled outputs and two measurements, temperature and pressure. The strategy combines nonlinear control laws where states are either estimated by extended Kalman filtering or predicted from the kinetic model. This advanced control has been implemented with success on an industrial reactor. [Copyright &y& Elsevier]

The Mild Combustion is characterized by both an elevated temperature of reactants and low temperature increase in the combustion process. These features are the results of several technological demands coming from different application fields. This review paper aims to collect information which could be useful in understanding the fundamentals and applications of Mild Combustion. The information in this field are still sparse, because of the recent identification of the process, so that many speculative considerations have been presented in order to make the whole framework more consistent and rich with potential new applications.A rigorous definition of Mild Combustion is preliminarily given in order to fix the input variables of the process. Under these constraints the influence of the physical, thermodynamic and chemical variables on the most relevant outlet parameters are analyzed.The physical aspects taken into account are atomization, evaporation, mixing and radiative heat transfer. In particular, the evolution of the mixing layer for high temperature diluted oxidant is analyzed. It is shown that mass fluxes through the stoichiometric isosurfaces are lower than those in not diluted conditions and that the annihilation of these isosurfaces is enhanced in the Mild Combustion conditions. Both effects infer low rates of heat release according to the experimental results reported in the literature.The thermodynamic aspects are dealt through the comparative analysis of the minimum, maximum and equilibrium temperature profiles versus the mixture fraction in the whole allowable range for the diluted and not-diluted cases.The chemical aspects have been analyzed in relation to the chemical kinetics rates for different oxidative routes and the temporal evolution of the self-ignition process. The molecular oxygen addition, the hydroperoxide dissociation and atomic hydrogen oxidation are evaluated in wide pressure and temperature ranges. In such a way self-ignition regimes which rely on different preferential chemical kinetics routes are identified and comparison between diluted/not diluted conditions are performed for a fixed evolution time. In this case it is shown that Mild Combustion conditions extend the pressure–temperature range, in which the oxidation is depressed, at relatively low pressure, whereas the ‘ceiling temperature’ is shifted to lower temperature for Mild Combustion condition at higher pressure.The second part of the review shows the potentialities of the diluted high temperature air combustion in applications related both to efficiency and pollution of thermal generation as well as to abatement of the pollutants along the flue gas stream of a primary combustion system.Some selected examples in these fields as land-base gas-turbines, boiler combustion chamber and domestic heating systems are presented. In these, the emphasis, is put preliminarily on aspects related more to efficiency than to pollution reduction, even though this target is implicitly taken into consideration. Then environmental benefits are dealt in relation to the major and minor species, either organic or inorganic, which can be produced in gas/liquid combustion. They include carbonaceous material, unburned hydrocarbons, nitrogen oxides and sulphur oxides.Finally, a classification of the possible processes relevant along the whole fuel transformation in Mild Combustion is given. In particular ‘clean’, ‘cleaning’, ‘clearing’ combustion processes are identified as a convenient categorization in relation to the incorporation of pre-combustion or post-combustion units in the main combustion systems. [Copyright &y& Elsevier]