Construction Of Reactor Research Articles

Understanding the chemistry of mesostructured porous nanoreactors.

Porous nanoreactors mimic the structures and functions of cells, providing an adaptable material with multiple functions and effects. These reactors can be nanoscale containers and shuttles or catalytic centres, drawing in reactants for cascading reactions with multishelled designs. The detailed construction of multi-level reactors at the nanometre scale remains a great challenge, but to regulate the reaction pathways within a reactor, designs of great intricacy are required. In this Review, we define the basic structural characteristics of porous nanoreactors, while also discussing the design principles and synthetic chemistry of these structures with respect to their emerging applications in energy storage and heterogeneous catalysis. Finally, we describe the difficulties of the structural optimization of these reactors and propose possible ways to improve porous nanoreactor design for future applications.

Construction and evaluation of electrophotocataltic tubular reactor in phenol degradation

Contamination of the environment is one of the main threats to achieving sustainability. Even though there have been significant legal efforts to regulate parameters for effluent disposal, conventional treatment methods often prove to be ineffective, resulting in the incomplete removal of pollutants. This inefficiency leads to serious environmental issues, such as the toxicity of biomes, which is closely related to the bioaccumulation of harmful substances. In response to this challenge, this study aimed to develop and optimize an electrophotocatalytic reactor for the remediation of a synthetic phenol solution using advanced oxidative processes (AOPs). By applying these processes, we observed that the characteristics of the reaction medium allowed for a maximum pollutant removal yield of 54.73% over a 3-hour operation period in a continuous recirculation regime. Despite the promising results, the study revealed the influence of additional factors that were not considered, which are likely important in further optimizing the reactor's efficiency for real-world applications.

Nuclear energy and international relations: the external strategy of Russia’s Rosatom

AbstractThis article analyses the role of nuclear energy in global politics today through the perspective of three International Relations theories: realism, liberalism and dependency theory. It contends that concepts developed to investigate oil and gas geopolitics do not always apply to the nuclear sector due to its greater complexity. The supply chain for nuclear power involves different, interrelated stages—notably the provision of natural uranium, of enriched uranium, and the construction and servicing of nuclear reactors—which have distinct leading suppliers and relationships of dependence. We illustrate this through a case study of Russia’s state nuclear company Rosatom. Rosatom leads in the provision of enriched uranium and reactor construction. This enables Russia to deepen economic and political relations with Rosatom’s clients. Even after its attack on Ukraine, Russia has not ‘weaponized’ Rosatom’s international business. Its strategy focuses on consolidating its reputation as a trustworthy partner, especially in the Global South and China.

Construction and evaluation of a CSTR reactor for the treatment of textile effluents.

Construction and evaluation of a CSTR reactor for the treatment of textile effluents.

Methanization Test of Water Hyacinth and Azolla in Co-digestion and Fertilizing Value of Digestates in Benin (West Africa)

Faced with the need for an alternative energy source following the extreme pressure exerted on woody resources accompanied by the increase of aquatic pests which invade water resources, the construction of mini reactors producing clean energy, biogas based on these invasive plants becomes a challenge. This investigation aims to assess the methane production potential of water hyacinth and Azolla in co-digestion and the fertilizing quality of the digestates obtained. A bio methanization test based on various combinations of organic substrates composed of water hyacinth and Azolla alone or in co-digestion under laboratory conditions at mesophilic temperature and neutral pH after 27 days was carried out. The source of enrichment in anaerobic microorganisms for fermentation processes in micro bioreactors consists of fresh pig manure. It appears that the combination of organic substrates including 75% of water hyacinth generated the maximum quantity of methane which is 1234 liters for one ton of organic substrates. This methane production is 1.93 times greater than that of the bioreactor containing water hyacinth alone, 1.90 times that containing azolla, 1.5 times that containing 25% water hyacinth +75% azolla then 3.04 times that containing the bioreactor composed of a high proportion of crushed Azolla filiculoides. The digestates are rich in N, P, K, Ca and Mg and had an amending power according to the NFU 44051 standard. For the construction of bioreactors with aquatic pests for the benefit of communities, co-digestion with a combination of substrates with a high proportion of water hyacinth is suggested.

Heat pipe type double-containment vessel as passive safety system for small modular reactors

This paper proposes a new concept of a passive safety system for small modular reactors as a heat pipe type double-containment vessel. The proposed system configures an additional vessel outside the existing one and functions as a heat pipe that utilizes phase change heat transfer to reduce the requirement of a large pool design. The double-containment vessel features a design consisting solely of the evaporation and condensation sections for heat pipe function with compactness. The ultimate heat sink only serves as a condenser part for the double-containment vessel, therefore significantly reducing the volume of stored fluid. The study numerically evaluates several postulated accidental cases to compare the performance of the double-containment vessel using the thermal hydraulic system code, MARS-KS. Even for serious conditions such as multiple failure accidents without safety systems operation, the double-containment can secure extra golden time to core damage by more than 2,090 sec compared to the original design. This study highlights the feasibility and potential of the heat pipe-based double-containment vessel as a passive safety system, enhancing the safety and reliability of small modular reactors. This kind of design can provide the advantages of safety and economics in the construction of small modular reactors.

Green Molecular Reactor Boosting the Photocatalytic Aerobic Oxidation of Sulfides in Clean Solvent

AbstractThe synthesis of sulfoxides has long attracted considerable interest due to their pivotal role in organic synthesis, pharmaceutics and environmental protection. Oxidation of the corresponding sulfides is recognized as the most effective strategy. Traditional oxidation methods, however, fall short of the growing demands of green chemistry. Photocatalytic aerobic oxidation has thus garnered attention, employing the greenest and most sustainable oxidants—oxygen or air—and sunlight as the energy source. Nevertheless, these reactions are typically conducted in potentially pollutive organic solvents rather than in the greenest solvent, water. To facilitate this organic transformation in aqueous phase, molecular reactors that can encapsulate reactants within their confined pores and facilitate photocatalytic reactions have been developed recently. This Concept article summarizes the development of molecular reactors for the photocatalytic oxidation of sulfides and provides perspectives for the design and construction of effective photocatalytic molecular reactors.

Construction of electrochemical flow reactor: static mixing and micro-cell for dehydrogenation oxidation from TNT to 2,2’,4,4’,6,6’-hexanitrostilbene

From the electrochemical synthesis in beakers to the application of electrochemical reactors, flow electrosynthesis has become more and more prominent in the field of organic synthesis. But for multi-feed reactions, the problem of efficient mixing in the electrochemical reactor remains unresolved. A novel electrolytic cell was devised to facilitate thorough mixing of various feedstocks during electrochemical oxidation. With structural optimization guided by computational fluid dynamics (CFD) simulations, the choice of reaction channels was deliberated upon, alongside an elucidation of the mixing mechanism. The reactor's performance was assessed based on both mixing efficiency and electrochemical oxidation capability with the synthesis of 2,2’,4,4’,6,6’-hexanitrostilbene (HNS) serving as a model. The high efficiency of the electrochemical reactor was verified by the enhanced yield, purity, and faradaic efficiency of HNS. It is environmentally friendly and easy to realize industrial production.

Quorum sensing improves start-up and stability of sulfate-reducing biocathode in autotrophic microbial electrolytic cell for low-organic-carbon sulfate wastewater treatment

The utilization of autotrophic microorganisms in microbial electrolysis cell (MEC) is promising for the treatment of industrial wastewater that lacks carbon source and electron donor. However, constructing an autotrophic biocathode is time-consuming, and the population induction technologies may alleviate this challenge. In this study, N-butyryl-L-Homoserine lactone (C4-HSL) was added to the MEC biocathode run for 60 cycles to investigate quorum sensing effects on sulfate reduction efficiency, electrochemical properties, microbial community structure and functional genes. The results showed that the addition of C4-HSL significantly expedited the startup of the MEC cathode with a 47.1 % reduction. Its electrochemical performance was also improved, with the cyclic voltammetry area averaging 1.19 times higher than that without the addition of the signaling molecule. Under the regulation of C4-HSL, the biodiversity in the initiation phase became richer. The relative abundance of Desulfobacterota and sulfate reduction-related functional genes increased to 4 times and 1.43 times of the control, respectively. This discovery reveals the potential of signaling molecules in enhancing the construction of sulfate wastewater treatment reactors and improving the performance of autotrophic microorganisms, aiming to improve wastewater treatment efficiency and broaden the practical possibilities of MEC.

Life cycle analysis of a network of small modular reactors

Abstract Small modular reactors are highly-touted as the next-generation nuclear reactors that can provide alternatives to baseload energy sources such as coal and gas. Lesser dependence on these energy resources may enable faster development in poorer countries. The small modular reactors’ modularity allows for faster construction times vis-à-vis large reactors. Together with this, as more of the same reactors are constructed, costs are expected to decrease with learnings made from the experience of producing the previous one. From a technological point of view, Small modular reactors are capable of generating energy at a lower cost compared to large reactors due to the lesser capital costs that arise from faster construction times. However, it is important to understand the overall environmental impact of small modular reactors when used as a network of reactors to generate energy. Life-cycle analysis is an accepted methodology to assess various environmental impacts of technology from cradle to grave. In this work, a case study of the development of a network of small modular reactors with a unique supply chain is presented. Since small modular reactors can be sited separately, and with its comparatively higher number of reactors and plants, the same network of small modular reactors has a higher carbon footprint than a single large reactor. However, this result should be carefully considered together with other criteria that affect the decision-making in the construction and development of small modular reactors or large reactors as these may outweigh marginally higher carbon footprints, such as economic, social, and political benefits.

Low-Cost Alternative for Online Analysis of Volatile Organic Compounds.

The use of online mass spectrometry for detecting volatile organic compounds (VOCs) has proven to be a powerful technique, allowing for real-time analysis of many chemical and biochemical processes. Unfortunately, online mass spectrometry has had limited application due to high instrument costs and limited availability. Here, we detail the design, construction, and performance characteristics of a custom ion-molecule reactor retrofitted to a commonly used single quadrupole mass spectrometer to operate as an online chemical ionization mass spectrometer (CIMS). This low-cost modified CIMS is capable of limits of detection below 10 parts per trillion for select VOCs including dimethyl sulfide, dimethylamine, and trimethylamine.

Temperature Effects of Nuclear and Electronic Stopping Power on Si and C Radiation Damage in 3C-SiC.

Silicon carbide has been considered a material for use in the construction of advanced high-temperature nuclear reactors. However, one of the most important design issues for future reactors is the development of structural defects in SiC under a strong irradiation field at high temperatures. To understand how high temperatures affect radiation damage, SiC single crystals were irradiated at room temperature and after being heated to 800 °C with carbon and silicon ions of energies ranging between 0.5 and 21 MeV. The number of displaced atoms and the disorder parameters have been estimated by using the channeling Rutherford backscattering spectrometry. The experimentally determined depth profiles of induced defects at room temperature agree very well with theoretical calculations assuming its proportionality to the electronic and nuclear-stopping power values. On the other hand, a significant reduction in the number of crystal defects was observed for irradiations performed at high temperatures or for samples annealed after irradiation. Additionally, indications of saturation of the crystal defect concentration were observed for higher fluences and the irradiation of previously defected samples.

ARGOS. La puesta en marcha de un reactor nuclear experimental en Barcelona

The article provides information about the construction and development of an experimental nuclear reactor in Barcelona, its operation, and subsequent dismantling. The influence that the conferences in Geneva in 1955 and 1958 and the experimental reactors presented there had on the selection of the Argonaut-type reactor is highlighted. Articles published between 1958 and 1962 that provide technical details about the reactor’s construction process are mentioned and described. The reactor’s dismantling process is also discussed. Additionally, the involvement of institutions and persons in the reactor’s development, as well as the training of technicians who participated in its construction, are also cited.

Protocell Flow Reactors for Enzyme and Whole-Cell Mediated Biocatalysis.

The design and construction of continuous flow biochemical reactors comprising immobilized biocatalysts have generated great interest in the efficient synthesis of value-added chemicals. Living cells use compartmentalization and reaction-diffusion processes for spatiotemporal regulation of biocatalytic reactions, and implementing these strategies into continuous flow reactors can offer new opportunities in reactor design and application. Herein, the fabrication of protocell-based continuous flow reactors for enzyme and whole-cell mediated biocatalysis is demonstrated. Semipermeable membranized coacervate vesicles are employed as model protocells that spontaneously sequester enzymes or accumulate living bacteria to produce embodied microreactors capable of single- or multiple-step catalytic reactions. By packing millions of the enzyme/bacteria-containing coacervate vesicles in a glass column, a facile, cost-effective, and modular methodology capable of performing oxidoreductase, peroxidase and lipolytic reactions, enzyme-mediated L-DOPA synthesis, and whole-cell glycolysis under continuous flow conditions, is demonstrated. It is shown that the protocell-nested enzymes and bacterial cells exhibit enhanced activities and stability under deleterious operating conditions compared with their non-encapsulated counterparts. These results provide a step toward the engineering of continuous flow reactors based on cell-like microscale agents and offer opportunities in the development of green and sustainable industrial bioprocessing.

A new perspective on density and strength loss profiles at the surface of thermally oxidized nuclear graphite

Oxidation of graphite components could influence their designed life in a high-temperature nuclear reactor. The oxidized regions could potentially lower the allowed stress capacity. The American Society of Mechanical Engineers rules for the design and construction of graphite-moderated reactors recommend that subsurface regions that might become excessively damaged by oxidation during reactor operation be identified and excluded from geometry and stress calculations. Identification of oxidation-affected regions is possible, in principle, through complex modeling exercises of reactor behavior during hypothetical accident scenarios coupled with graphite oxidation models, but this procedure may not have the precision needed for informed decisions. This paper proposes an alternate method, based on interpretation of a series of well-designed oxidation experiments, which could augment the designer's tools. The procedure is illustrated by data on oxidation by air of several graphite grades (NBG-18, PCEA, IG-110, R4-650) that are corroborated with independent literature information, when available. The Wichner model for graphite oxidation used for this analysis provides conservative results that could be quickly implemented in the design process.

Enhancing Safety in the Construction of Small Modular Reactors (SMRs) and Microreactors (MRs) through Improving Guidelines and Involving Digital Technology Tools

Enhancing Safety in the Construction of Small Modular Reactors (SMRs) and Microreactors (MRs) through Improving Guidelines and Involving Digital Technology Tools

Construction of micro-tubular proton-conducting ceramic electrochemical reactor (MT-PCER) for ammonia production at atmospheric pressure

Micro-tubular ceramic electrochemical reactors have attracted significant interest due to their high packing density, large electrode specific surface area, and long triple phase boundaries (TPBs). In this work, a micro-tubular proton-conducting ceramic electrochemical reactor (MT-PCER) with a unique microstructure is facilely constructed for ammonia synthesis at atmospheric pressure. BaCe0.7Zr0.1Y0.2O3-δ (BCZY as the electrolyte)/Ni–BaCe0.7Zr0.1Y0.2O3-δ (Ni-BCZY as the catalytic cathode) dual-layer hollow fibers with open finger-like pores on the inner surface are first fabricated using a modified co-spinning/co-sintering process to form a basic MT-PCER. Fe-based catalyst was then coated into these open finger-like pores in Ni-BCZY layer as an additional catalytic cathode of the MT-PCER. The unique open finger-like pores structure of the basic MT-PCER decreases the mass transfer resistance and also provides space for loading additional catalysts, contributing towards the higher catalytic performance of the MT-PCER. However, the Faradaic efficiency for ammonia formation remained low, indicating that the cathode catalyst required further improvement. This fabrication technique provides a flexible method to adjust the cathode catalysts to optimize the catalytic performance of the MT-PCERs.

The role of the NPT in preventing further proliferation of nuclear weapons

The entire atmosphere created by the Treaty on the Non-Proliferation of Nuclear Weapons and its presence in the world played one of the responsible roles, since after the US bombing of Hiroshima and Nagasaki, nuclear weapons were never used in a military situation (unless, of course, you take into account that the nuclear powers conducted more than 2,000 nuclear explosions at their test sites).
 It can be said that this is the result of a broad consensus reached by the international community on the prevention of the proliferation of nuclear weapons and other types of weapons of mass destruction, as well as the result of the actual operation of the Treaty on the Non-Proliferation of Nuclear Weapons during its more than 50 years of existence. Currently, no bilateral or multilateral meeting on international security issues, including at the highest level, is held without a mention of nuclear non-proliferation, and it is often at the top of the agenda.
 The Treaty on the Non-Proliferation of Nuclear Weapons is an international legal and ethical norm that has entered the minds of millions of people. Many countries have developed and adopted national legislation establishing export control rules for materials used in the production of weapons of mass destruction, as well as other laws (customs, etc.) to help ensure the non-proliferation of weapons of mass destruction. Extensive training of young experts in basic knowledge to support the international non-proliferation regime of nuclear weapons is ongoing.
 In the field of technology, scientists and experts in reactor engineering are working in many countries to build nuclear power plants that will not produce materials used to create weapons of mass destruction. Many scientists are working to prevent the construction of reactors that threaten the proliferation of technologies and nuclear materials capable of producing nuclear weapons and other weapons of mass destruction.
 The conclusion of the Treaty on the Non-Proliferation of Nuclear Weapons and the establishment of an international non-proliferation regime contributed to a fundamental change in the world’s attitude to nuclear weapons. From the first impression in the eyes of the world public that nuclear weapons are a «genius» discovery, the latter is increasingly perceived as a mortal danger that threatens human existence, and this idea penetrates deeper and deeper into the consciousness of millions of people.

The construction of a microalgal-bacterial biofilm reactor for enhanced swine wastewater treatment

Traditional biological wastewater treatment methods face challenges in treating swine wastewater with a low carbon-to‑nitrogen ratio. Microalgae show great potential in low-cost swine wastewater treatment for nutrient recovery. This study investigated the effects of altering the carbon/nitrogen/phosphorus (C:N:P) ratio in swine wastewater and immobilizing microalgae for enhancing treatment using Desmodesmus sp. A C:N:P proportion of 106:16:1 was determined to be optimal for treatment. The implementation of an inclined plate bioreactor facilitated microalgal adherence, forming a biofilm that improved treatment efficiency. The biofilm exhibited removal rates of 92 % for ammonia nitrogen (NH4+-N), 98 % for total phosphorus (TP), and 99 % for chemical oxygen demand (COD). The harvested biomass from the biofilm was 7.6 times higher than that from the suspended system with a high content (63 %) of fatty acids (C16:0, C18:0, C18:1n9c and C18:2n6c) suitable for biodiesel production. Proteobacteria were dominant in the biofilm, while Firmicutes and Bacteroidetes contributed to effective organic matter and nitrogen removal. These findings present a promising technology for cost-effective swine wastewater treatment and resource recovery.

Design and construction of a single orifice oscillatory flow reactor for the continuous production of biodiesel from sunflower oil

Biodiesel, a renewable energy replacing fossil fuels, exhibits eco-friendly traits with beneficial lubrication properties. This research aims to design and construct a single-orifice oscillatory flow reactor to reduce the reaction time, improve the mixing process, and increase efficiency. The response surface method was used for the analysis of independent parameters like molar ratio (1:6–1:12), temperature (30–50 °C), reactor length (1–3 m), and catalyst concentration (0.75%-1.25%) on yield as the dependent variable. Elevated temperature up to 50 °C enhances conversion from 61.91% to 69.51%, peaking at 65.43% by 60 °C, adjusting the molar ratio to 1:9 boosts biodiesel conversion from 58.70% to 69.51%, dropping by 4% at 1:12 ratio. Catalyst concentration at 1% heightens conversion from 48.82% to 69.51%, but at 1.25%, it falls to 57.26%. Increasing reactor length to 2 m yields a 20% boost, while at 3 m, conversion drops by 4%. Optimal conditions, at 40 °C, 1:9 ratio, 1% catalyst, and 3 m reactor, resulted in a 91.98% conversion percentage. Experimental verification at the suggested point yields an 89% conversion, aligning acceptably with the model’s prediction. Biodiesel meets EN 14214 standards, positioning it as a viable diesel fuel alternative.