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Currently, biofuels represent a solution for the European Union in the transportation sector in order to reduce the greenhouse gas (GHG) emissions and the dependency of fossil fuels. Biodiesel from vegetable oils is a solution for countries with low GDP per capita to strengthen the internal agriculture, provide jobs, and reduce the use of fossil fuels. In this study, we model and simulate a temperature regulator designed for the biodiesel transesterification process in a discontinuous batch reactor, using methanol and a homogenous basic catalyst. The simulation was based on the kinetical model of the transesterification reaction and the mathematical model of the reactor. We considered molar ratios of alcohol/oil of 6:1 and 9:1, respectively, to shift the reaction equilibrium towards the production of fatty acid methyl esters. In the design of the simulation, the methanol boiling point was considered a restriction, therefore, temperatures below 65 °C were imposed. The results demonstrate that the increase in temperature results in a decrease in the reaction time and a higher yield, especially for the 6:1 molar ratio reaction, and that the optimum temperature for the batch reactor is of 60 °C. Automatic control improves the performance and costs of production. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels has led to a search for new methods of fuel and chemical production from biomass. One of the methods of converting biomass into valuable products is the process of pyrolysis. This process has been extensively researched in recent years due to the rising prices of energy and chemicals. This work contains basic information on the pyrolysis process concerning the individual components present in the biomass and the types of biomass used in the pyrolysis process. Particular attention was paid to sewage sludge, the management of which is a big challenge. The influence of the most important process parameters (temperature, heating rate, residence time of the solid and vapor, reaction atmosphere) on the pyrolysis products (char, oil, and gas) was presented. The paper presents an overview of the reactors used in the pyrolysis process, from slow to fast pyrolysis, together with their efficiency, advantages, and disadvantages. The analysis of the application of other thermochemical processes for producing the energy used in the process of pyrolysis and in the drying of the biomass was carried out. Two industrial-scale installations for the pyrolysis of sewage sludge were presented. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Argonauta research reactor at the Institute of Nuclear Engineering - IEN operates, under normal conditions, at powers ranging from 1.7 to 340 W, developing activities of a scientific-technological nature in the areas of neutron radiography, radionuclide production and conduction from experimental practices to graduate courses at CNEN research institutions and other Brazilian institutes of science and technology. During some security operations, the presence of investigators, students and/or operators inside and around the main hall of the Argonauta is required. Therefore, it is important to assess normal occupational exposure conditions when the reactor is in critical condition. This makes it possible to verify in greater detail the equivalent doses of ambient gamma radiation contained by the combustion of the fuel element inside the reactor room and in the surrounding areas, according to the Radiation Protection Plan (RPP) of this installation. In this work, a didactic activity was carried out to familiarize the students of the first period of the Master's Course in Nuclear Engineering, at the Military Institute of Engineering, with the procedures involved in the radiometric survey of the free, controlled and subsequent locations of this nuclear installation. This practice aims to identify the doses to which Occupationally Exposed Workers (OEW) and the general public are admitted, verifying compliance with regulatory requirements regarding the monitoring of environmental and local activities, as well as a comparison between the radiation monitors used.

Anhydrous ammonia (NH3) is a promising carbon-free fuel for internal combustion engines (ICEs) that can be generated from renewable energy sources and stored at high energy density. Ammonia is typically mixed with a small fraction of hydrogen (H2), which serves as combustion promoter to achieve stable combustion over a large range of engine operation. To overcome the difficulties of storing hydrogen, ammonia can be converted to hydrogen onboard by means of a catalytic reactor fed by waste thermal energy from the engine exhaust or by partial oxidation. This work explores an alternative method of producing hydrogen by partial oxidation of fuel-rich ammonia–air mixtures to hydrogen in an engine cylinder while generating useful work. Such an approach eliminates the need for costly catalyst materials and poses the possibility of a dedicated reforming cylinder to provide hydrogen for other cylinders in a multi-cylinder engine. Experiments were conducted in a single-cylinder spark-ignition (SI) engine with parametric sweeps of intake temperature, intake pressure, equivalence ratio, and spark timing. Experimental results show that 6% exhaust gas hydrogen concentration is attainable and 40% of the unburned fuel energy can take the form of hydrogen. Rich equivalence ratios produced higher concentrations of hydrogen and elevated intake temperatures extended the rich stable-operation limit of the engine. Low order chemical modeling yields insights into hydrogen production throughout the engine cycle, revealing that initial consumption of ammonia is advanced of hydrogen production and that competing elementary reactions for the formation and destruction of hydrogen drive its net quantity in the exhaust.

In some reactors, ammonia and its radiolytic product (H2) are used to scavenge the oxidizing species (H2O2, O2, and •OH). A reducing chemical environment is thus created and the pH of the coolant is regulated simultaneously. In the present study, the radiolytic behaviors of deoxygenated ammonia solution were studied in the γ-ray field. The impacts of N2 pressure, gas-liquid volume ratio, and temperature on deoxygenated ammonia solution radiolysis were investigated. The pH and the concentrations of residual ammonia, H2, and nitrogen oxides (NO2- and NO3-) were analyzed. The results revealed that the variation of N2 pressure (0.5~5.0 MPa) and gas-liquid volume ratio had no influence on the concentrations of residual ammonia and nitrogen oxides. NO2- and NO3- concentrations were approximately 1 mg/L at room temperature when the absorbed dose was 28.8 kGy. However, the apparent concentration of H2 significantly decreased with the N2 pressure and gas-liquid volume ratio. The loss fraction of ammonia considerably declined from 26.5% to 8.4% when the temperature increased from 25 to 200 ℃, demonstrating that the radiolysis of ammonia was suppressed at the elevated temperature. However, the concentrations of NO2- and NO3- increased to 34 and 3 times, respectively, at 200 ℃ compared to those at 25 ℃. In addition, a radiolysis model of ammonia-containing coolant was established in the present study. The maximum relative error between experimental data and calculation results at any temperature was 4.1%. The model was thereafter used to calculate residual ammonia concentration with the absorbed dose under different initial ammonia concentrations. The results revealed that it was necessary to replenish ammonia regularly when using it alone to inhibit oxidizing species.

The purpose of this work is to present a convenient design approach for metal hydride reactors that meet the specific requirements for hydrogen storage. Three methods from the literature, the time scale, the acceptable envelope, and the reaction front, are used to estimate the maximum thickness of the bed allowing for sufficient heat transfer. Further heat transfer calculations are performed within the framework of standardized heat exchanger via the homemade design software, to generate the complete geometry and dimensions of the reactor. LaNi5 material packed in tubular units based on conventional shell-and-tube heat exchanger is selected for analysis for an expected charging time of 500 s, 1000 s, and 1500 s. Apparently, the smaller the expected charging time, the smaller the bed thickness and hence the diameter of the tubular units. After comparison, the method of reaction front was adopted to output standard tube diameters and calculate the weight of the reactor. Significant weight differences were found to result from the varying wall thickness and number of tubes. In general, the shorter the expected charging time, the more tubular units with a small diameter will be built and the heavier the reactor. Fluent 2022 R2 was used to solve the reactor model with a tube diameter of 50 mm supposed to fulfill a charging time of 1500 s. The simulation results revealed that the reaction fraction reaches its maximum and the hydrogen storage process is completed at 500 s. However, because the calculation is conducted on meeting the heat exchange requirements, the average temperature of the bed layer is close to the initial temperature of 290 K and stops changing at 1500 s. The applicability of the method to the design of metal hydride reactors is thus confirmed by the temperature and reaction fraction judgment criteria.

A fusion reactor based on the spherical tokamak is very likely to be completely non-inductive for the majority of the plasma ramp-up and steady-state phases, due to the limitations imposed on the central coil assemblies by the compact design. Efficiency gains from solenoid-driven current cannot be relied upon. It is also critical that an electricity-producing plant maximises the wall-plug efficiency of its heating and current drive (HCD) system, this being one of the largest consumers of recirculating power. It is therefore essential that the HCD system is well-optimised for current drive efficiency in order to meet the goal of net electricity production. The UK’s Spherical Tokamak for Energy Production (STEP) reactor design program has recently taken the decision to use exclusively microwave-based heating and current drive actuators for its reactor concepts. We present the optimisation of an electron cyclotron current drive scheme for a spherical tokamak reactor, based around the STEP concept, arriving at a solution which overcomes the limitations imposed by the spherical tokamak geometry in terms of microwave access and high trapped particle fraction. The solution uses high-field side absorption and a mix of fundamental and 2nd harmonic O mode, with overall power requirements reducing with increasing number of frequencies used. An additional fundamental frequency is also added to further boost the efficiency during non-inductive plasma ramp.

Nonlinear gyrokinetic simulations correctly predict particle as well as ion and electron energy fluxes of high confinement plasmas with a negative triangularity cross sectional shape, showing that core transport in these plasmas is well described by standard gyrokinetic models. Experimentally inferred power balance fluxes are mostly reproduced within one standard deviation across a wide portion of the minor radius. Experimental conditions are reproduced by ion scale simulations, without the need to include density and temperature profile curvature effects. The experimental case is used as baseline to predict that the non-dimensional confinement scaling in negative triangularity plasmas increases strongly with plasma current while slightly degrading at increasing normalized pressure and decreasing collisionality. Recent experiments showed that low toroidal rotation negatively impacts confinement; consistent with the experiment, simulations predict that low rotational shear significantly affects confinement unless the plasma effective charge is maintained above a minimum level. Core confinement is predicted to significantly degrade in low aspect ratio devices.

Chemical looping combustion has the advantages of inherent CO2 separation and significantly reducing the NOx production. The circulation reactors are the core site for oxygen carrier redox and fuel conversion. The current research status of chemical looping combustion pilot systems was analyzed from three aspects of reactor type, solid material circulation mode and design theory. At present, chemical looping combustion pilot plants with heat input of 10~3 000 kW have been established in the world, and the technical readiness level is sixth. The mainstream technical route of chemical looping combustion is that the air reactor and fuel reactor both adopt the fluidized bed. The system circulation flow rate of the chemical looping pilot plants is generally lower than 25.5 kg/(m2·s), which makes it difficult to achieve self-heating operation. Finally, we introduced the latest progresses including the theoretical research, the development of a high-efficiency carbon stripper, the design of a high-flux circulating flow rate chemical looping combustion unit, and the reactor system design, etc.

Distillation is the process of separating two or more components of a liquid based on their boiling points in which the material to be evaporated is contained. Distillation is simply done by heating/evaporating the liquid and then changing the vapor phase to liquid with the help of a condenser. Research on the distillation column or reactor has been carried out to improve the distillation system but is still discussing the reactions that occur due to heating and the final product of the distillation process. An analysis based on the second law of thermodynamics is developed, known as exergy analysis to obtain information about the thermodynamic efficiency and locations that have low energy efficiency so that energy savings can be targeted. The distillation reactor as one of the vital tools at the separation stage is very important to note is the manufacture of the reactor. To reduce heat loss that occurs by adding a heat protective layer (heat cover) on the distillation reactor. The heat protection materials used are burlap sacks and glass wool to be implemented for rural communities and also become prototypes of appropriate technology application tools. The use of a 3 cm jute alloy on the inside and 3 cm glass wool on the outside gave the highest heat transfer value of 7864.21 watts. The increase was 43% of those who only used burlap. An increase of 37% over those using only glass wool. A 3% improvement over an alloy of 3 cm glass wool inside and 3 cm burlap on the outside.

Pyrolysis is a thermochemical process by which biomass is decomposed by heating in the absence of oxygen and the resulting emitted gases and settled bio-char are used for energy supply. Cypress pruning residues due to their gums content are a good source for pyrolysis. In this study, a reactor equipped with a screw conveyor was built and used for pyrolysis of stems and leaves of cypress tree. Then the effects of temperature and residence time of the reactor on their thermal decompositions was investigated using factorial experiments based on a completely randomized design. In these experiments, temperature was set at 5 levels from 300 to 500°C, with 50 degrees intervals and the residence time was set from 5 to 30 minutes with 5 minute intervals. The results showed that, at 1% significant level, both resident time and reactor temperature and their interaction had significant effects on bio-char yields for both stem, and leaves. The analysis of TG/DTG diagrams showed that the bio-char was formed from 200 to 500°C. The highest rate of decomposition of hemicellulose was at 340°C, and it was 450°C and 580°C for cellulose and lignin, selectively. The final rich carbon content of bio-char was formed after 750°C which resulted 23% for the stems and 28% for the leaves. The pyrolysis experiments with different retention time in the reactor indicated that, in general, the amount of bio-char decreases as the retention time increased.

Ethylene is a very important material in petrochemical industries, whose chief application is producing polymers. The steam cracking of naphtha or ethane is usually applied to produce ethylene. A small amount of acetylene is produced in this process. The amount of acetylene in the product stream should not exceed 1 ppm, because it is harmful to polymerization catalysts in downstream units. The acetylene hydrogenation unit is designed for acetylene removal in industrial plants. In this unit, the removal of acetylene up to 1 ppm in the product stream and ethylene’s selectivity are of great importance. In this paper, the dynamic optimization of acetylene hydrogenation reactors of Marun petrochemical complex with considering catalyst deactivation is presented. In this study, the differential evolution (DE) method is used as a powerful method for determination of a dynamic optimal temperature profile to achieve maximum of ethylene’s selectivity in a period of 720 operating days. Then, the optimal results are compared with the condition wherein the inlet temperatures of the reactors are maintained constant at 55 ˚C and with the condition wherein the inlet temperatures of them increase linearly from 55 to 90 ˚C. The results showed when the inlet temperatures are kept 55 ˚C, the outlet acetylene exceed 1 ppm, but the best selectivity is achieved. With a linear increase in the inlet temperatures, the outlet acetylene is below 1 ppm but the selectivity is decreased. An optimal temperature profile maximizes the selectivity when the outlet acetylene is below 1 ppm.

Aerobic composting has been one of the fastest ways to fertilize soil products via organic decomposition under an oxygen-rich environment. Among them, the aerobic composting reactor can be one of the most important facilities during aerobic composting in recent years. However, some challenges are still remained in the aerobic composting reactor, including the long duration, low maturity homogenization, and utilization efficiency. In this study, an optimal vertical reactor of aerobic composting was designed with three independent layers using E-Discrete Element Method (EDEM) and Fluent simulation. An effective volume of 120 L was also obtained in the developed reactor. A series of simulations and experiments was implemented to verify the structural parameters. Each stage was also controlled to shorten the duration of the composting process in this reactor. The continuous process of feeding in and out of feedstocks was established, according to the actual requirement of the reactor during aerobic composting. ANSYS platform was finally used to verify the mixing system of the reactor. The results showed the maximum stress and deformation of the reactor were 75.288 MPa and 3.6804 mm during aerobic composting, respectively, fully meeting the high requirements of standard design. At the same time, the EDEM and Fluent simulation were then used to analyze the movement of materials during aeration and discharging. The results showed that the discharge rate of the reactor was 98.14% at the string speed of 20 r/min, and the gas volume fraction was above 90% during aeration. Better performance of the reactor was achieved in the discharge and aeration system during this time. A series of experiments was carried out on aerobic composting, particularly with the chicken manure and corn straw that were mixed at a ratio of 1:4 (dry weight basis). It was found that there was no significant difference in the temperature of the same layer during composting of the three batches (P>0.05). Specifically, the duration of the high-temperature period (higher than 50 °C) was maintained 9, 7 and 5 days, respectively, for the three raw materials. It infers that the composting fully met the ecological demand of harmless in this case. More importantly, the pH values were between 8.0 and 9.0, whereas, the electrical conductivity (EC) values were between 2.0 and 3.0 mS/cm during composting of three batches. There was a significant difference in the pH and EC values of each layer (P<0.05). However, there was no significance (P>0.05) at the same layer during the three batches. Moreover, the seed germination rates were also all above 100%. In addition, the degradation rates of volatile solid (VS) were 14.99%, 16.03%, and 13.24%, respectively, in the three batches. Hence, the stable properties of composting were achieved in the excellent performance of the developed reactor. Therefore, the improved composting reactor can be expected to serve as the aerobic composting reactor in the utilization of agricultural wastes. [ABSTRACT FROM AUTHOR]

Copyright of Energy Chemical Industry is the property of Energy Chemical Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Food waste, which is the second largest component in landfills, generates excessive amounts of leachate and greenhouse gas. As a result, it has recently become a severe concern, mostly in the developing countries for its adverse impact on the environment. The addition of nutrients to organic waste limits the accumulation of volatile fatty acid (VFA) and accelerates the production of energy from food waste. The objective of the current study is to find out the effects of sludge addition on the decomposition and gas generation of separate components of food waste. This study was conducted for four combinations of reactors: two pairs containing meat and grain with the addition of a sludge content of 20% and 30%, respectively, as inoculum; another two pairs of reactors containing fruits and vegetables with a sludge content of 20% and 30%, respectively. Over the operation period, pH, volume, COD, and VFA tests were conducted for leachate while composition and volume measurements were done for the generated gas. Based on the results, it is observed that addition of sludge accelerated the decomposition of fruit and vegetable waste due to limited VFA accumulation compared to meat and grain. The maximum methane production was found in fruits and vegetable reactors at a rate of 6.7 L of methane per pound of food waste. For fruit and vegetable reactors, the CH4:CO2 ratio increased to as high as 8.5. On the other hand, for the meat and grain reactors, the increase in CH4:CO2 ratio was insignificant as they were in the lag phase. [ABSTRACT FROM AUTHOR]

Actually, the quality of water is one of the most important indicators of the human environmental impact, the control of which is crucial to avoiding irreversible damage in the future. Nowadays, in parallel to the growth of the chemical industry, new chemical compounds have been developed, such as dyes and medicines. The increasing use of these products has led to the appearance of recalcitrant pollutants in industrial wastewater, and even in the drinking water circuit of our populations. The current work presents a photoreactor prototype that allows the performance of experiments for the decomposition of coloured pollutants using photocatalysis at the laboratory scale. The design of this device included the study of the photometric technique for light emission and the development of a software that allows monitoring the dye degradation process. Open-source hardware platforms, such as Arduino, were used for the monitoring system, which have the advantages of being low-cost platforms. A software application that manages the communication of the reactor with the computer and graphically displays the data read by the sensor was also developed. The results obtained demonstrated that this device can accelerate the photodegradation reaction in addition to monitoring the changes throughout the process. [ABSTRACT FROM AUTHOR]

A large amount of pig slurry has been generated on the farm each year, particularly with the ever-increasing pig production in recent years. It is a high demand to fully utilize pig manure biogas slurry and microalgae cultivation at a large scale. In this study, a series of experiments were carried out on the multi-stage amplification cultivation with Chlorella E2E using pig manure biogas slurry on a pilot scale, according to the coupled mode of "indoor monoculture + outdoor monoculture + outdoor culture using biogas slurry". The raceway pond reactor was set as the largest area of 12.31 m³ in the pilot-scale experiments of "column reactor + plate reactor + runway pool reactor". An investigation was implemented to analyze the growth of Chlorella E2E performance in the pure and biogas slurry cultivation system. A systematic evaluation was also made to clarify the pollutants removal and the diversity of microorganisms in the microalgal cultivation system using pig manure biogas slurry under natural light conditions. Results showed that the Chlorella E2E was gradually adapted to the reactor environment after the multiple batches of pure culture and acclimatization. Specifically, the Chlorella E2E quickly reached the optimum growth state in the second column reactor in indoor monoculture, where the average maximum biomass reached 227.72 mg/L on the 70th day. The fitting relationship was favorable between the inoculum amount, cultivation time and bioaccumulation in each stage of the indoor reactor. A characteristic equation was obtained to predict the biomass yield or cultivation time, particularly for the management of the monoculture mode of Chlorella E2E. The growth capacity of Chlorella E2E in an outdoor monoculture plate reactor was significantly higher than that in an indoor column reactor, where 266.48 mg/L Chlorella E2E biomass was produced on the 14th day. In addition, the highest daily biomass productivity of Chlorella E2E and mean specific growth rate (μ) were achieved in 11.10 mg/L/d and 0.062 /d, respectively, in the flate bioreactors under natural light conditions. The reason was that the Chlorella E2E received sufficient light to effectively utilize the light energy under outdoor natural light conditions (the local average light intensity was 211.76 μmol/(m² ·s)). Correspondingly, the raceway pond was more suitable to culture Chlorella E2E for the pig manure biogas slurry than the flat plate reactor in outdoor culture using biogas slurry. The maximum biomass accumulation reached up to 245.98 mg/L with the highest Chemical Oxygen Demand (COD), NH4 + -N, and Total Phosphorus (TP) removal of 40.05%, 95.06%, and 97.52%, respectively. The short light path of the plate reactor was much more conducive to the light reception in the pure culture stage, compared with the raceway pond. Previously, the short light path failed to fully culture microalgae using biogas slurry, due to the low light transmittance of biogas slurry. By contrast, the mechanical mixing enhanced the microalgal production to relieve the dark color of the biogas slurry in the raceway pond. There were diverse microbes in the raceway ponds, particularly with the higher performance. A bacteria-algae symbiotic system was easily formed to maintain the stability of the cultivation system. A better performance was achieved to remove more pollutants from the biogas slurry. This finding can also provide a technical reference for the practical application of microalgae cultivation using biogas slurry. [ABSTRACT FROM AUTHOR]

Gamma spectrometry of the KAMINI reactor coolant lines at the selected spots/locations was carried out during 20kWt power and shutdown using portable spectrometers such as RIIDEye-X, RayMon (Cadmium Zinc Telluride), and hyper pure germanium.133Xe (81 keV),85m Kr (150 keV), and 135Xe (250 keV) isotopes could be identified. The spectra results did not indicate the presence of internal contamination due to any corrosion activation products such as 56Mn, 59Fe, 60Co, and fission products. The gamma radiation level observed during reactor power on the selected locations is only due to the fission product noble gases (FPNGs) and their short-lived radionuclides 88Rb and 138Cs generated and not any pipeline internal contamination.137Cs and trace quantities of 60Co were identified in the mixed bed regenerated liquid. The presence of 137Cs could be attributed due to the tramp fuel fissions. [ABSTRACT FROM AUTHOR]

Ecosystem destruction is one of today's significant challenges due to fast industrialisation and an increasing population. It takes several years for solid trash, such as plastic bottles and super-market bags, to decompose in nature. In addition, plastic disposal techniques such as landfilling, reuse, and incineration pose significant threats to human health and the environment. In this paper, we investigated whether the impact of mixing biodiesel with waste oil from recycled plastic on the resulting fuel mixture's yields better physical and chemical properties. Consequently, pyrolysis is one of the most advantageous and practical waste disposal methods as it is both environmentally benign and efficient. Pyrolysis is the high-temperature thermal breakdown of solid waste to produce pyrolytic oil. The pyrolytic (plastic) oil produced is converted to a hydrocarbon-rich pyrolytic fuel. Similar to diesel and gasoline, pyrolytic fuel has the same calorific value. Internal combustion engines may operate on pyrolytic fuel without suffering a performance reduction. Researchers examined engine performance and exhaust pollutants. The research discovered that the engine could operate on plastic pyrolysis fuel at full load, enhance brake thermal efficiency by 6–8%, and lower UBHC and CO emissions; however, nitrous oxide (NOx) emissions were noticeably higher. The findings demonstrated the possibility of using plastic pyrolysis fuel as a diesel substitute. [ABSTRACT FROM AUTHOR]

This review critically discussed recent developments in hydrothermal carbonization (HTC) of food waste and its valorization to solid fuel. Food waste properties and fundamentals of the HTC reactor were also covered. The review further discussed the effect of temperature, contact time, pressure, water–biomass ratio, and heating rate on the HTC of food waste on the physiochemical properties of hydrochar. Literature review of the properties of the hydrochar produced from food waste in different studies shows that it possesses elemental, proximate, and energy properties that are comparable to sub-bituminous coal and may be used directly as fuel or co-combusted with coal. This work conclusively identified the existing research gaps and provided recommendation for future investigations. [ABSTRACT FROM AUTHOR]

LTAG technology is a technology that selectively hydrogenates and saturates the polycyclic aromatic hydrocarbons of low quality FCC diesel fuel with high aromatic content and poor combustion performance, and then converts them into high octane gasoline or light aromatic hydrocarbons through FCC ad refining. Selective hydrodearomatic reaction is an important part of this technology. This paper mainly introduces the design features and application of reactors, heating furnaces and other equipment of the LTAG catalytic cracking diesel hydrogenation unit. The reaction heat of hydrodearomatic reaction is much higher than that of conventional hydrotreating reaction, so the design of this unit is slightly different from that of conventional hy- drotreating unit. A new LTAG diesel hydrogenation unit was built in a company. The process of two reactors in series and partial circulation was adopted. A reaction start-up heater was set. A heat exchanger was set between two reactors in series. The inlet temperature of the two reactors was controlled by the outlet temperature of the tube side and shell side of the heat exchanger. This design method can effectively save cold hydrogen and reduce energy consumption. [ABSTRACT FROM AUTHOR]

To improve the parameters of reactors and reduce the cost of generated electricity, we carry out research aimed at determining the most rational use of fuel. Different methods use different mathematical and physical models, which leads to some difference in the obtained data. One of these methods is the profiling of fuel assemblies. In this paper, we present the theory used in modeling and calculations by the Serpent 2 software package, consider methods of axial profiling of compositions in a reactor, and provide a comparison of the obtained results and substantiation of their reliability at an intermediate stage of the study. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Traditionally, spherical tokamak (ST) reactors are considered to operate in a steady state. This paper analyses the advantages of a pulsed ST reactor. The methodology developed for conventional tokamak (CT) reactors is used and it is shown that advantages of a pulsed operation are even more pronounced in an ST reactor because of its ability to operate at a higher beta, therefore achieving a higher bootstrap current fraction, which, together with a lower inductance, reduces requirements for magnetic flux from the central solenoid for the plasma current ramp-up and sustainment.

Large-scale photovoltaic power connected to the distribution network will raise the voltage at the system nodes， and， in serious cases， the voltage overlimit. Therefore， a voltage regulation strategy based on shunt and series reactors as well as genetic algorithm is proposed. Firstly， the causes of voltage rise in the distribution network and the roles of shunt and series reactors in voltage regulation are analyzed. Then， a reactive power optimization model with the objective of economic optimization is established， and the genetic algorithm is used to solve the optimal reactor configuration scheme. Finally， the effectiveness of the method is verified by simulating the IEEE 33-node system incorporated into a high-power PV plant based on the MATLAB simulation platform.

The application of video processing techniques are useful for the safety of nuclear power plants by tracking the people online on video to estimate the dose received by staff during work in nuclear plants. Nuclear reactors remotely visually controlled to evaluate the plant's condition using video processing techniques. Internal reactor components should be frequently inspected but in current scenario however involves human technicians, who review inspection videos and identify the costly, time-consuming and subjective cracks on metallic surfaces of underwater components. In case, if any frame of the inspection video degraded/corrupted/missed due to noise or any other factor, then it may cause serious safety issue. The problem of missing/degraded/corrupted video frame estimation is a challenging problem till date. In this paper a systematic literature review on video processing techniques is carried out, to perform their suitability analysis for NPP applications. The limitation of existing approaches are also identified along with a roadmap to overcome these limitations.

The performance of wet and advanced oxidation processes is considered to have many weaknesses concerning ozone and peroxone, specifically their characteristics against persistent organic compounds, as well as nitrogen-ammonia and amine-phenolic-based compounds. This is necessary to increase and improve the performance of the utilized plasma reactor, specifically the finer bubble size, as well as the intensity and reactivity (chemical reaction barriers) of the reacting species, to have a smaller impact on mass transfer or diffusivity in polar solvents. Therefore, this study aims to analyze the hydrodynamic characterization and several tests of the most important physicochemical parameters of a prototype nanobubble plasma ozone reactor, which is a reaction vehicle integrating the synergistic effect of a cold field. This reactor was used with a nanobubble-producing nozzle in a PFR (plug flow reactor), to increase the absorption ability of the plasma by water. The results showed that the oxygen and ozone solubilities, H2O2 production, and the synergy of these species were strongly influenced by the electric voltage, feed gas flow rate, and the O2 purity used in the injection system.

A comprehensive overview is presented to summarize the research works since 1982 on oxidative coupling of methane (OCM), a complex reaction network combining heterogeneous and homogeneous reaction steps. Fundamentals on reaction mechanisms and thermodynamics have revealed that the OCM process is highly exothermic and its C2+ selectivity and yield is critical in evaluating its commercial viability. Catalytic strategies have been put to enhance C2+ selectivity, improve C2+ yield and lower reaction temperature. The catalyst Mn-Na2WO4/SiO2 enables methane activation at a temperature of 800 °C and simultaneously a high C2+ selectivity of 70–80%, while the nanowire and La2O3-based catalysts enable to lower the reaction temperature to 200–300 °C and 500 °C, respectively. Reaction engineering aspects have also been dealt in many investigations in order to make the process technically feasible. Particularly, research works on reaction kinetics, reactor selection and reactor operating mode choice have been addressed. Intermediate cooling and distributed oxygen feed have been integrated into a multi-stage adiabatic fixed-bed reactor system to suppress the side oxidation reactions and improve the performance of the catalysts towards CH4 conversion and C2+ yield. This review paper proposes employing a circulating reactor system coupled with catalyst fine particles but having little internal diffusion resistance to maximize one-pass C2+ selectivity and yield of the OCM reaction and evaluate its industrial application potential.

[Display omitted] • A closed-flow photocatalytic system with O2 supply is developed. • The system is applied to recover gallium radioisotopes from complexes. • Capillary electrophoresis is suitable for the quantification of byproducts. This report describes the development and application of a flow photocatalytic reactor for the effective photodecomposition of organic compounds and the recovery of a targeted metal ion; specifically, we describe the decomposition of a gallium-ethylenediaminetetraacetic acid (Ga-EDTA) complex. The system includes a scrubber, which increases the amount of dissolved oxygen in the solution before entering the photocatalytic reactor. First, the decomposition efficiency of the developed reactor is evaluated using dimethyl sulfoxide (DMSO). The decomposition of DMSO is accelerated upon introducing oxygen from the scrubber into the flowline. Second, we employ this system for the decomposition of Ga-EDTA and evaluate the recovery of a Ga radioisotope (RI), which can serve as a probe in positron emission tomography for medical diagnoses. The byproducts generated during Ga-EDTA photodecomposition are monitored by capillary electrophoresis, and the released Ga3+ concentrations are determined by inductively coupled plasma atomic emission spectroscopy for the stable isotope of Ga and with a scintillation detector for RI-Ga. After 30 min under ultraviolet irradiation, 54 % of the RI-Ga released during the photodecomposition of RI-Ga-EDTA was recovered. [ABSTRACT FROM AUTHOR]

• Continuous hydrogenation reactor coupled to continuous extraction unit. • For global selectivity, the most influential parameter is partition coefficient. • Highly influential variables are hold-up and residential time. • Over 90% impunity removal was achieved. • Not suitable from polishing operation. The potential for coupling a continuous hydrogenation reactor with a continuous extraction unit was investigated through computer simulation of series of mixers/settlers coupled to a slurry reactor in a closed loop. The process has the potential to replace the regeneration of extraction solvents by distillation. Additionally, the system eliminates the need to treat the entire feedstock when refining a complex mixture. It is believed that the reaction of the extract retains valuable components in the feed that are not extracted and could undergo undesirable hydrogenation. The parameters for the simulation model were obtained from correlations and published data. The system was expected to exhibit a pseudo-first-order reaction rate in relation to the impurity concentration due to its low concentration in the extract. This is expected to result in high hydrogen-to-impurity ratios, which can be advantageous from a reaction driving force perspective. Solvent degradation by hydrogenation and solvent-impurity reactions are thought to be the main problems for the extraction-hydrogenation process. [Display omitted] [ABSTRACT FROM AUTHOR]

This review is aimed at researchers in air pollution control seeking to understand the latest advancements in volatile organic compound (VOC) removal. Implementing of plasma-catalysis technology for the removal of volatile organic compounds (VOCs) led to a significant boost in terms of degradation yield and mineralization rate with low by-product formation. The plasma-catalysis combination can be used in two distinct ways: (I) the catalyst is positioned downstream of the plasma discharge, known as the "post plasma catalysis configuration" (PPC), and (II) the catalyst is located in the plasma zone and exposed directly to the discharge, called "in plasma catalysis configuration" (IPC). Coupling these two technologies, especially for VOCs elimination has attracted the interest of many researchers in recent years. The term "synergy" is widely reported in their works and associated with the positive effect of the plasma catalysis combination. This review paper investigates the state of the art of newly published papers about catalysis, photocatalysis, non-thermal plasma, and their combination for VOC removal application. The focus is on understanding different synergy sources operating mutually between plasma and catalysis discussed and classified into two main parts: the effect of the plasma discharge on the catalyst and the effect of the catalyst on plasma discharge. This approach has the potential for application in air purification systems for industrial processes or indoor environments. [ABSTRACT FROM AUTHOR]

• A review on anaerobic digestion (AD) for biogas production is presented. • Technological limitations associated with different reactor configurations have been summarized. • Continuous stirred tank reactors (CSTR) technology and the effect of various qualitative and quantitative factors affecting AD are discussed. • Improved reactor configuration, use of additives, bacteria and pretreatment methods intensify AD in CSTR. • The energy balance of AD in CSTR can be improved by optimizing the system components. Waste pollution can negatively impact the ecosystem directly or indirectly. Utilizing waste as a resource to produce value-added products, like biofuels, is one option to address this problem. This would create a circular economy, which is in line with the Sustainable Development Goals (SDGs) 5, 7, 8, and 9 of the United Nations (UN). Anaerobic digestion (AD) is a technology that humans have extensively used to generate renewable energy. However, a great deal of research is required to optimize biogas production under diverse conditions. Several factors have been considered pertaining to the design and operation of digesters to ensure cost-effective and efficient digestion. This article summarizes the underlying AD processes and the operating parameters used to enhance process efficiency. Considering older research and recent developments, a comprehensive summary of the theory of continuous stirred tank reactor (CSTR) technology for AD has been presented. The novelty of this review article lies in the emphasis on advanced intensification strategies to stabilize the AD process in CSTR for enhanced biogas/biomethane production. Furthermore, energy balance calculations of CSTR for biogas production are reviewed to promote the practical application of the technology on a global scale. While pretreatment enhances the substrate's surface area, eliminates lignin, and decreases the crystallinity of cellulose to stimulate microbial uptake, co-digestion provides feedstock accessibility to the microorganisms and improves CH 4 yield. Energy balance studies of CSTR revealed that the majority of the energy consumed is used during heating, mixing, and feedstock transportation. In addition, the use of digestate enhances the energy recovery efficiency of the CSTR system. With proper process optimizations, AD for biogas production can help the country overcome current energy issues. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigates the feasibility of siting a nuclear power plant (NPP) within a densely populated university campus. Site selection for NPPs is a complex process involving numerous interconnected factors. To address this complexity, we employ system dynamics (SD) modeling, a methodology renowned for its ability to quantify both technological and social aspects. Our simulation results indicate that public acceptance (PA) is a critical determinant in site selection. In the fourth month of the simulation, the model's values were identical in both PA and non-PA scenarios. However, subsequent simulations revealed a significant divergence, with PA-implicated values reaching 85.398 compared to 24.240 in the non-PA scenario. This disparity underscores the primacy of PA in the decision-making process. Given the extended timeline of NPP construction, the gap between PA and non-PA outcomes is likely to widen further, particularly in the context of positive public sentiment toward the NPP. The insights gleaned from this research can be applied to other industries, such as oil refineries, where the potential for atmospheric pollution due to toxic gas leaks necessitates careful site selection. • ●The site selection of NPP is analyzed in a campus town. • ●PA is a factor to consider in the site decision. • ●Simulations show the quantified results. • Future site section could be applied using this method. [ABSTRACT FROM AUTHOR]

A novel solid-state neutron and gamma radiation monitor-dosimeter based on biopolymer polylactic acid (PLA) is presented. The resulting detector (PLAD) technology takes advantage of property changes of the renewable PLA resin when subject to ionizing nuclear radiation. A simple yet rapid and accurate (±10%) low-cost (TM Co-60 irradiator, and the PUR-1 12 kW fission nuclear research reactor were utilized, respectively. Irradiation absorbed doses ranged from 1 to 100 kGy. Acetone bath temperature was varied from ~40 °C to ~54 °C. Results revealed a strong dependence of MLD on acetone bath temperature between neutron and gamma photon dose components; this allowed for the unique ability of PLAD to potentially perform as both a neutron-cum-gamma or as a gamma or neutron radiation dosimeter and intensity level detector. A linear trend is found for combined neutron and gamma radiation doses from 0 to 40 kGy when dissolution is conducted above 50 °C. The important potential ability to distinguish neutron from gamma radiation fields was scoped and found to be feasible by determining MLD at 45 °C. The potential was studied for simultaneous use as an in-core neutron and gamma monitor of an operating 3 GWt light-water reactor (LWR). Scoping tests were conducted with the pre-irradiated (@ 20 °C) PLAD resin beads followed by heating to in-core LWR coolant (300 °C) conditions for ~30 s corresponding to the time to reach ~40 kGy total doses in a typical 3 GWt LWR. MLD results were unaffected, indicating the exciting and unique potential for in situ (low-cost, accurate and rapid) simultaneous mapping of neutron and gamma radiation fluxes, related dosimetry, and fission power level monitoring.

Proton exchange membrane fuel cells take advantages of high efficiency, no pollution and good fuel adaptability. The green energy network formed by combining fuel cells with reliable hydrogen production is an effective way to achieve carbon neutrality. It is expected to promote the technological research and upgrading of new energy vehicles, unmanned air vehicles, ships and other industries those use fuel cells as electricity and thermal power source. However, a safe and stable hydrogen supply technology is a major bottleneck limiting the development of fuel cell power generation applications in mobile scenarios. Hydrogen production by in-situ methanol reforming is hopeful to make a breakthrough in mobile hydrogen source technology based on fuel cell. In this paper, the research progress of methanol reforming hydrogen production, the research progress of reactors for methanol reforming hydrogen production and the application of methanol reforming fuel cell power generation system were reviewed to provide reference and guidance for promoting the commercial development and application of methanol reforming fuel cell in the field of new energy.

Two cases of abnormal acetylene content rise in the oil chromatogram of ultra-high voltage reactors are introduced in this paper. To monitor the internal condition of the reactor in real time and judge the type of defect， a partial discharge critical monitoring device is used for long-term monitoring. Critical monitoring results in case 1 show that there is a partial discharge caused by floating potential and weak insulation defects inside the reactor that lead to the rapid content rise of acetylene. Critical monitoring results in case 2 show that the intermittent partial discharge signal inside the reactor is an external interference signal near the north side of the ultra-high voltage reactors， and there is no obvious internal discharge signal. As to the iron core clamp ground current test， the internal defect type is the high temperature and overheating gas produced by the multi-point grounding of the magnetic circuit， and the chromatogram growth has nothing to do with the partial discharge. It is discovered by disassembly that the equipotential copper tape of the ground screen connected to the clamp on reactor body 1 in case 1 has broken discharge traces and the insulation paperboard is damaged. In case 2， the iron yoke of reactor body 1 and the magnetic shield of the upper body are overlapped， and the contact surface is obviously ablated with no obvious discharge trace inside， which excludes the possibility of internal discharge. The disassembly results are consistent with the analysis conclusions of the partial discharge critical monitoring system， verifying the effectiveness of the partial discharge critical monitoring method in power equipment defect analysis. The method can evade misjudgment due to external signal interference.

Neutron moderators, such as nuclear-grade graphite, are essential components of high-temperature nuclear reactors. Their primary functions are to degrade the energy of fission-born neutrons into an energy range that promotes further fission and to serve as the central core structure. This paper will discuss historic reactor moderator materials, which are relatively simple monolithic materials each having intrinsic benefits and limitations. Additionally, a new class of engineered composite moderators is presented for which two examples are fabricated: magnesia-matrix composite systems with either beryllium-based or metal-hydride entrained phases. In additions to presenting their route to fabrication effectiveness as advanced moderators is discussed.

Abstract Background Caprine tuberculosis (TB) is a zoonosis caused by members of the Mycobacterium tuberculosis complex (MTBC). Caprine TB control and eradication programmes have traditionally been based on intradermal tuberculin tests and slaughterhouse surveillance. However, this strategy has limitations in terms of sensitivity and specificity. Different factors may affect the performance of the TB diagnostic tests used in goats and, subsequently, the detection of TB-infected animals. In the present study, the effect of two of the factors that may affect the performance of the techniques used to diagnose TB in goats, the topical administration of corticosteroids and a recent pre-sensitisation with tuberculin, was analysed. Methods The animals (n = 151) were distributed into three groups: (1) a group topically treated with corticosteroids 48 h after intradermal tuberculin tests (n = 53); (2) a group pre-sensitised with bovine and avian purified protein derivatives (PPDs) 3 days before the intradermal tuberculin test used for TB diagnosis (n = 48); and (3) a control group (n = 50). All the animals were tested using single and comparative intradermal tuberculin (SIT and CIT, respectively) tests, an interferon-gamma release assay (IGRA) and a P22 ELISA. Results The number of SIT test reactors was significantly lower in the group treated with corticosteroids when compared to the pre-sensitised (p 0.05). No significant effect was observed on IGRA and P22 ELISA due to corticosteroids administration. Nevertheless, a previous PPD injection affected the IGRA performance in some groups. Conclusions The application of topical corticosteroid 24 h before reading the SIT and CIT tests can reduce the increase in skin fold thickness and subsequently significantly decrease the number of positive reactors. Corticosteroids used can be detected in hair samples. A previous pre-sensitisation with bovine and avian PPDs does not lead to a significant reduction in the number of intradermal tests reactors. These results are valuable in order to improve diagnosis of caprine TB and detect fraudulent activities in the context of eradication programs.