Prototype Reactor Research Articles

Formation temperature range expansion and energy storage properties of CO2 hydrates

A hybrid thermal cycle is developed by storing liquid CO2 using an intermittent heat pump cycle (IHP) and forming CO2 hydrates (CHRs) using a CHR thermal cycle (CHT) with a high charge/discharge efficiency at low temperatures. The proposed technology for physical batteries operates the IHP in summer, when outside temperatures are high, and the CHT in winter. The operating period of a CHT with a high charge/discharge efficiency can be extended and the annual efficiency of IHP/CHT hybrid systems can be improved by increasing the temperature of the low-temperature heat source of the CHT. Therefore, cyclopentane, the crystal structure of which differs from that of CHRs, is added to the host fluid in this study. Then, the CHR formation temperature range is expanded based on the results of the experiment. When the CHR formation temperature (outdoor air temperature as low-temperature heat source) is increased from the conventional 0 °C–15 °C, the amount of generated CHR slightly exceeds the amount generated by a conventional system. These findings show that a CHT system, which conventionally requires a low-temperature heat source (approximately 0 °C), can now be operated at a moderate temperature of 15 °C. When CHR are formed at 0 °C for 18 h and then dissociated at 25 °C, the prototype reactor produces a high-pressure dissociated gas of 20.5 MPa at an initial formation pressure of 5 MPa. When cyclopentane is added to water in a 3500 cm3 vessel at the appropriate concentration, CO2 hydrates large enough to be produced even at outdoor temperatures of about 15 °C or less. The proposed system can be operated at outdoor temperatures below 15 °C. These results represent the close realization of the proposed CHT.

Multi-field coupling and collaborative optimization design of the solar thermochemical cycle process based on ceria

Most solar reactors commonly encounter challenges such as high-temperature gradients, suboptimal photo-thermal efficiency, and limited catalyst utilization. This lack of coordination in the design of solar reactors stems from the inadequate integration of the photothermal-chemical coupling synergistic relationship within the reactor. We developed a comprehensive multi-physics coupling mathematical model that incorporates optics, heat transfer, and chemical reactions to facilitate the cooperative optimization design of solar reactors. This study unveils the multi-field coordination mechanism within solar reactors. The optimization design of the secondary concentrator, reactor structure, fluid flow layout, and porous media catalyst structure was systematically carried out. A two-step thermochemical cycle of methane reducing cerium oxide decomposing water vapor to produce hydrogen was used as the reaction system to analyze the performance of the prototype reactor. The influences of ray power, reaction flow rate, and oxygen carrier mass on the solar-to-chemical efficiency were analyzed. The optimization results demonstrate that, by considering factors such as light power, mass transfer flow, and oxygen carrier mass within the optimization framework, the solar chemical energy conversion efficiency can reach a maximum of 38.75%.

A new prototype reactor for the fast microwave-assisted decarboxylation and extraction of cannabinoids in olive oil from Cannabis inflorescences

Several different Cannabis-based pharmaceutical preparations have been approved for medical treatments. Standardization to ensure specified phytocannabinoid contents and to maintain the integrity of the product is therefore required. Olive oil is clearly a safe and edible solvent suitable for the galenic preparation of ready-to-use Cannabis extracts. Pharmacists can use several non-standard procedures for this purpose, most of which involve the heat treatment of the plant matrix (i.e. the female inflorescences) for 2 h. In order to allow the “neutral” and more biologically active forms of the major phytocannabinoids to be extracted, prior thermal treatment of the plant matrix is desirable. This work investigates a new prototype microwave (MW) reactor (Ethos Lean) specifically designed for the decarboxylation of the acidic cannabinoids in Cannabis inflorescences and their subsequent extraction into oil. Both of the steps to produce the oily extract were carried out in the Ethos Lean's cavity with special accessories; a rotating drum for the decarboxylation process and a glass reactor with a stirrer for the extraction step. The variables considered in the process optimization were time and temperature, according to which the instrument automatically calibrated the power output. In collaboration with a hospital pharmacy, the efficiency of the device has been evaluated by comparing the results obtained with those of exhaustive decarboxylation in a conventional oven and ethanol extraction. A comparison was also made with conventional procedures in olive oil. Thanks to the rotating drum, which is sensitive to dielectric heating, the complete and homogeneous decarboxylation of phytocannabinoids was rapidly achieved (30 min, 120 °C), even with discrete quantities of inflorescences (150 g) and without releasing the characteristic intense odor into the laboratory. The exhaustiveness (100% yields of both CBD and THC) of MW-assisted extraction process in olive oil was achieved with 30 min irradiation at 90 °C. Furthermore, the possible decarboxylation occurring during MW-assisted extraction in oil and the effect of cooling time on the final yields have also been evaluated.

Development of a microfluidic photochemical flow reactor concept by rapid prototyping.

The transfer from batch to flow chemistry is often based on commercial microfluidic equipment, such as costly complete reactor systems, which cannot be easily tailored to specific requirements of technologies such as DNA-encoded library technology (DELT), in particular for increasingly important photochemical reactions. Customized photoreactor concepts using rapid prototyping technology offer a modular, flexible, and affordable design that allows for adaptation to various applications. In order to validate the prototype reactors, a photochemical pinacol coupling reaction at 368nm was conducted to demonstrate the transfer from batch to flow chemistry. The conversion rates were optimized by adapting the design parameters of the microfluidic flow photoreactor module. Subsequently, the photoreactor module has been extended to an application with DNA-tagged substrates by switching to LEDs with a wavelength of 454nm. The successful recovery of DNA confirmed the feasibility of the modular-designed flow photo reactor. This collaborative approach holds enormous potential to drive the development of DELT and flow equipment design.

Flue gas cleaning approach based on jet reactor prototype research

The motivations for developing innovative jet ejector scrubbers, which meet the contemporary requirements for reducing sulfur oxide emissions in marine engineering, are presented in this paper. The proposed jet ejector scrubber was equipped with a cylindrical mixing section. The selected operating conditions enabled the development of a mixing shock process that afforded favourable conditions for sulfur oxide absorption. The first series of experimental investigations were carried out on a laboratory scale for a 40-kW diesel engine equipped with jet ejector scrubbers at a sulfur mass content of 0.35% in the fuel. The tests were conducted for various applied motive nozzles, as well as a nominal mixing section length-to-diameter ratio (L/D) of 25. These tests confirmed the complete reduction of SO2 using the jet reactor, as well as the reduction of other chemical compounds in the exhaust gas without using additional filters, e.g., reduction of heavy metals and transition metals by 85–98% and 71–74%, respectively, and the removal of total organic carbon (TOC) from exhaust gas at a level greater than 46%. The second series of experiments investigated a diesel engine with a maximum power of 250 kW under marine operating conditions. In this case, the effect of the mixing section length was tested. For fuels with 1.0% and 1.5% sulfur mass contents, full reduction of sulfur oxides was obtained for various loads of the engine. A maximum SO2/CO2 ratio of 0.18 was obtained for the ejector with an L/D of 25 and an engine load of 200 kW. However, this is significantly lower than the required limit of 4.3 according to the IMO.

Physical system behavior and energy flow analysis of a solar driven hydrogen production plant based on two-step thermochemical redox cycles

Two-step thermochemical water splitting using concentrated solar power offers promising potential for green hydrogen production as a part of a future sustainable energy economy. In this study, a system and energy flow analysis of a large scale 250 kW reactor prototype is presented by using a complex 3D-simulation model. Thus, the physical dynamic system behavior and potential efficiency improvements are discussed with respect to plant design and operational strategy. Regarding the plant design, different kind of heat losses as well as the influence of reactor design parameters and material modifications are analyzed. Regarding the operational strategy, crucial control parameters as cycle durations, temperatures, and mass flow rates are varied in a broad range and analyzed with respect to plant efficiency. By comparing commonly used operational strategies, the temperature swing operation turns out to be by far more efficient than any isothermal or near-isothermal operation for the current plant concept.

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

Digitizing protocols into single reactors for the one-pot synthesis of nanomaterials

Upgradation of methane in the biogas by hydrogenation of CO2 in a prototype reactor with double pass operation over optimized Ni-Ce/Al-MCM-41 catalyst

The upgradation of methane in biogas by hydrogenation of CO2 has been currently recognized as a promising route for efficient full utilization of renewable biogas with potential benefits for storage of renewable hydrogen energy and abatement of greenhouse gas emission. As a main constituent of biogas, CO2 can act as a backbone for the formation of additional CH4 by hydrogenation, then producing higher amounts of biomethane. In this work, the upgradation process was investigated in a prototype reactor of double pass operation with vertical alignment using an optimized Ni-Ce/Al-MCM-41 catalyst. The experimental results show that the double pass operation that removes water vapor during the run can significantly increase CO2 conversion, resulting in higher CH4 production yield. As a result, the purity of biomethane increased by 15% higher than a single pass operation. In addition, search for optimum condition of the process was carried out within an investigated range of conditions including flowrate (77–1108 ml min−1), pressure (1 atm–20 bar), and temperature (200–500 °C). The durability test for 458 h was performed using the obtained optimum condition, and it shows that the optimized catalyst can perform excellent stability with negligible influence by the observed change in catalyst properties. The comprehensive characterization on physicochemical properties of fresh and spent catalysts was performed, and the results were discussed.

A reduced-order modeling of a tubular solar reactor for long duration thermochemical energy storage

The storage of solar energy in a solid form, referred to as a “solar fuel”, can be achieved through a process known as endothermic solar thermochemistry. This process transforms the absorbed solar energy into a stable and retrievable form that can be stored for extended periods of time. This paper presents a low–order heat transfer model of a counter–current tubular falling bed reactor designed to produce thermally reduced magnesium manganese oxide pellets for long duration thermochemical energy storage. The energy required for the endothermic reduction was supplied by concentrated solar energy or renewable electricity via indirect heating of the gas and solid reactants flowing in a ceramic tube. The counter-current gas flow enhances the mixing of the solid particles with the heat recuperation zone, allowing the gas and particles to enter and exit the tubular reactor close to room temperature. The reactor was vertically oriented and was heated circumferentially by an adjustable level heat flux along a finite segment of its length. The temperature distribution of the reactor in response to transient changes along the tube was modeled by considering conduction, convection, and radiation heat transfer. Governing equations for the heat transfer model were solved by discretizing the reactor tube into a finite number of control volumes and using an energy balance for the heat exchange between the reactor wall, gas, and particles within the control volume. The energy absorbed during this endothermic reaction was modeled numerically by fitting the data of the chemical conversion rate with the corresponding temperature of particles in the heating zone. The numerical model has been experimentally validated using a reactor prototype made of a 121.92 cm alumina tube heated by a 7 kW electric tube–furnace. The alumina tube receives magnesium manganese oxide pellets of 3.66 ± 0.516 mm in diameter from the top, and a counter–current gas flow from the bottom. The reactor wall temperature was monitored by six thermocouples installed along the reactor tube length. The experimental procedure was numerically simulated, and the temperature variation along the reactor tube was compared with a matrix of experimental runs for a range of particles mass flowrates (0.75–1.25 g/s) and corresponding gas flowrates (36–65 SLPM). The reactor system was heated gradually from room temperature to a steady state temperature of 1673 K, and then cooled down to room temperature. The heating and cooling processes were simulated, and the numerical and experimental results were compared throughout processes. The numerical model showed similar trends to the experimental results, with an error of 0.69 to 7.9 % for the particle inlet and 0.7 to 7.9 % for the gas inlet during steady-state operation. The proposed numerical model can be implemented as a simplified physical model to design a feedback control system to regulate reactor temperature.

Integral and Separate Effects Test Facilities To Support Water Cooled Small Modular Reactors: A Review

This study reviews previous experimental facilities and test programs relevant to water-cooled reactor system design and analysis to meet regulatory compliances. This study aims to find the best solution for designing the required experiments, obtaining necessary test data, and verifying the developed computer code/models to support the new reactor design and development while minimizing cost and time while leveraging experiences from previous facilities to minimize. Nuclear reactor licensing requires supportive design, analysis, and experimental results to ensure the safety of the full-scale prototype reactor in regular operation, as well as during postulated accident scenarios. These reactor design analyses are generally performed using system codes and other associated simulation tools that require assessment, verification and validation using an appropriate experimental dataset. Experimental facilities used for reactor system safety analysis and system code assessments are categorized into integral effects test (IET) and separate effects test (SET) facilities. These IET and SET experiments and studies use geometrically scaled systems to reproduce the prototype system behavior at a reasonable cost, albeit with some scaling-related distortions. The design challenge of these model facilities is to identify and minimize scaling distortions while reproducing the most important operational phenomena in steady-state operation and in postulated accident scenarios. Lessons learned from previous experimental facilities, models, and correlations can support the development of new multipurpose, scaled, hybrid, integrated, and modular experimental facilities for advanced light water-cooled small modular reactors (SMRs). Successful operation of these facilities can significantly reduce upfront reactor development and demonstration costs and time to deployment.

Comparison of Temperature Rise Test Methods for Series Reactors Connected with High Voltage Power Capacitors

In substation, phase advance capacitors are used to improve the power factor. Series reactors are generally connected with the capacitors to reduce the waveform distortion and suppress the inrush current. The fifth harmonic current usually flows into the series reactors for a high voltage power capacitor. Japanese Industrial Standards provide three types of temperature rise test methods, and manufacturer chooses one of them. However, which test method should be selected has not been examined. In this paper, compare the advantages and disadvantages of the test methods using a prototype reactor.

Modelling, design and simulation of plasma magnetic control for the Spherical Tokamak for Energy Production (STEP)

Magnetic controller performance requirements and design solutions for the Spherical Tokamak for Energy Production (STEP) are driven by the need to produce equilibrium and scenario trajectories, maintaining steady plasma vertical stabilization and shape control for a period of thousands of seconds or longer while avoiding contact with the plasma-facing components (PFCs). Axisymmetric magnetic control schemes including vertical stabilization, plasma current control, plasma shape control and poloidal field coil current control for the STEP Prototype Reactor (SPR) concept are being developed using a suite of control analysis tools (known collectively as TokSys) supporting the integrated plasma control design process. The vertical growth rate based on a linear rigid plasma response model in TokSys is used for assessing the controllability of the vertical instability in SPR. TokSys closed-loop simulations with the axisymmetric non-linear, free-boundary evolution code, GSevolve, are performed for the assessment, identification, and verification of algorithm implementation and controller performance for the various axisymmetric control systems. Dynamic control performance and controllability are shown to be consistent with noise-affected scenario requirements under reasonable power supply and sensor performance assumptions.

Characterizing the seismic response of a molten salt nuclear reactor

AbstractOne Generation IV nuclear reactor, which uses a fluoride salt as a coolant, graphite reflector blocks as a moderator, and circulating buoyant TRISO pebbles as fuel is at an advanced stage of development. To characterize the seismic behavior of components of this reactor, validate numerical models for analysis, and develop recommendations for design, a set of earthquake‐simulator experiments on a scaled model of the reactor vessel and its internals was executed on a six‐degree‐of‐freedom earthquake simulator. The model was seismically isolated at its base using two types of spherical sliding bearings. The scaled model involved representations of the prototype reactor vessel, core barrel, reflector blocks, coolant, and spherical fuel pebbles. The material and geometric properties of different test components were selected based on a dynamic similitude scaling analysis and an approximate length scale of 0.4. Four sets of three‐component earthquake motions were used as inputs for testing. Instrumentation on the test specimen recorded the dynamic responses of the outer vessel, core barrel, and reflector‐block assembly, the hydrodynamic responses (sloshing and hydrodynamic pressure) of the liquid coolant, pebble consolidation under earthquake shaking, and the behavior of the isolation systems. This paper describes the design of the experiments and presents key results from the tests. The dynamic responses of the outer vessel, core barrel, and the reflector blocks revealed that the components responded as a unit for the intense shaking used in the experiments. The sloshing response of the fluid in a thin annulus near the perimeter of the vessel was heavily damped. The change in the packing fraction of the pebble bed under repeated, intense 3D earthquake shaking was less than 3%. Seismically isolating the vessel substantially reduced demands on its internal components.

Cold plasma studies on the influence of surface microstructured thickness in the secondary electron emission from tungsten coatings

The Secondary Electron Emission (SEE) from the Plasma Facing Components, (PFCs) affects the plasma sheath and edge structure of magnetically confined toroidal plasmas with effects on the Scrappe Off Layer (SOL), heat transport and incident plasma heat flux to the divertor targets. It is also behind the performance degradation in aerospace devices as Hall thrusters. In future reactor prototypes using tungsten (W) components, much more demanding and longer term conditions for the exposed PFCs are expected. These scenarios will exacerbate the material degradation of the exposed surfaces that will change its morphology, thus modifying its plasma material interaction behavior. In such scenario, specific studies on the influence of the microstructure in the tungsten SEE yields become necessary. In these laboratory experiments, the SEE emission of different microstructured tungsten coatings exposed to helium Glow Discharge (GD) plasmas has been analyzed by using a previously developed laboratory technique. It enables the characterization of the I-V characteristics of the biased sample and, at the same time, the acquisition of the electron incident flux by using a gridded probe adjacent to the exposed sample. Different microstructured W coated samples differing in coating thickness (2500 nm and 500 nm) and primal substrate surface finishing (translated in final differences within the W coating topologies) were analyzed, also including cold rolled tungsten and original stainless steel (SS) substrate (material in which the microstructured tungsten film was deposited) as benchmarks for comparison. The overall results have shown that the presence of a 2500 nm thick microstructured W coating decreases the SEE yield of tungsten (cold rolled) up to a factor 40% at electron mean energies of 100-175 eV. Conversely, 500 nm coatings did not reduce the SEE yield even showing an increase at 25-100 eV. The final increase/decrease in the obtained SEE yields seems to be more influenced by the microstructured coating thickness (where the role of intrinsic differences in oxygen content of the surfaces is discussed) rather than other questions possibly derived by the differences in surface topology (ordering, directionality and/or roughness of the microstructure features).

Novel Pilot-Scale Photocatalytic Nanofiltration Reactor for Agricultural Wastewater Treatment

Nowadays, the increased agro-industrial activities and the inability of traditional wastewater treatment plants (WWTPs) to eliminate recalcitrant organic contaminants are raising a potential worldwide risk for the environment. Among the various advanced water treatment technologies that are lately proposed for addressing this challenge, the development and optimization of an innovative hybrid photocatalytic nanofiltration reactor (PNFR) prototype emerges as a prominent solution that achieves synergistic beneficial effects between the photocatalytic degradation activity and size exclusion capacity for micropollutant molecules. Both these features can be contemporarily endued to a multitude of membrane monoliths. The physicochemical and the photoinduced decontamination properties of the titania materials were firstly determined in the powder form, and subsequently, the structural and morphological characterization of the obtained titania-modified membrane monoliths were accomplished. The PNFR unit can operate at high water recovery and low pressures, exhibiting promising removal efficiencies against Acetamiprid (ACT) and Thiabendazole (TBZ) pesticides and achieving the recycling of 15 m3/day of real agro-wastewater. The obtained results are very encouraging, demonstrating the integration of titania photocatalysts in a photocatalytic membrane reactor as a feasible technological solution for the purification of agricultural wastewater.

Development of Used Cooking Oil Circulation Reactor for Biodiesel Production as Learning Media of Vocational Mechanical Engineering Student

This study aimed to develop and test the feasibility of a waste cooking oil-based biodiesel reactor prototype media used as a learning medium with a circulation system. The method in this research is Research and Development using the Waterfall model. The stages in the waterfall development model are (1) requirements definition including (needs analysis, analysis of used cooking oil characteristics, analysis of renewable energy, hardware requirements), (2) implementation and unit testing, (3) integration and system testing including: (testing the reactor, and testing the appropriateness of the media and materials), (5) operation and maintenance include: (testing the biodiesel reactor to students ). The research subjects were three lecturers as material expert validators and media experts and ten mechanical engineering vocational students as users to test the product's feasibility. The research results are as follows; development of biodiesel reactor media and results of feasibility research by media experts got an average score of 4.48 with the category "very feasible." Assessment by material experts got an average score of 4.5 with the category "very feasible," and ratings from users got an average score of 4.095 with the category " decent."

Production of hydrogen and carbon nanofilaments using a novel reactor configuration: hydrodynamic study and experimental results

A novel reactor configuration combining two beds, a central fluidized bed and an annular mobile bed, was designed for the production of hydrogen and carbon nanofilaments via dry reforming of gases produced from the pyrolysis of plastic waste. This combination allows for easy recovery of these nanomaterials and, since the mixture of catalyst and carbon formed is continuously fluidized, it also prevents blockage. Understanding the hydrodynamics is crucial for choosing the optimal operating conditions. Thus, a cold mock-up unit of the same size has been built and used. Since the gases produced by plastic pyrolysis are mainly composed of unsaturated hydrocarbons, the prototype reactor setup has been operated using ethylene as a surrogate molecule. The preliminary experimental results of the reactor operation with ethylene obtained so far are very promising and confirm the operability of the process. Next step is to operate continuously for longer time and reach a production of 1kg/h of carbon nanofilaments.

Optimization of up-flow velocity and feed flow rate in up-flow anaerobic sludge blanket fixed-film reactor on bio-hydrogen production from palm oil mill effluent

The present study aims to optimize key operational parameters of the up-flow anaerobic sludge blanket fixed-film (UASFF) reactor using response surface methodology (RSM). A central composite design (CCD) has been applied to accomplish thirteen experimental runs given two main variables, namely feed flow rate (Qf), and up-flow velocity (Vup). The maximum hydrogen content, hydrogen production rate (HPR), hydrogen yield (HY), and COD removal were achieved at 55%, 4800 mL H2/cycle, 321 mL H2/g-COD, and 24.33%, respectively at Qf 8 L/cycle (HRT = cycle = 10.5 h) and Vup 2.0 m/h. The performance of the parameters from the optimum identified area was assessed at Qf 5.5 L/cycle (HRT = 15.3 h), and Vup 1.8 m/h, resulted in a maximum hydrogen content, HY, and HPR of 72%, 340 mL H2/g-COD, and 5100 mL H2/cycle, respectively. At optimum conditions, Clostridium sensu stricto 1 was found to be the dominant hydrogen-producing bacteria in the system. The results of this study may provide a practical basis for developing a UASFF reactor prototype based on empirical data.

A Trilaminar-Thermosensitive Hydrogel Catalytic Reactor Capable of Single/Tandem Catalytic Switchable Ability

The present endeavor is to develop a highly-intelligent catalytic reactor prototype which is able to autonomously adapt to the environment and provides an in-situ double-shift catalytic ability. By seeking inspiration from nature, this objective is achieved by developing a self-adaptive hydrogel catalytic reactor which held a catalytic trilaminar structure capable of reverse thermosensitive properties. With increasing temperatures, the catalytic tri-layers of this catalytic reactor would function in a sequential way (i.e., one negative temperature response layer, one support layer and one positive temperature response layer) and as a result, led to the single-tandem double-shift catalytic ability. This catalytic reactor individually presented single/tandem catalytic process at relatively low temperatures or high temperatures through the cooperative work of the three layers. In this way, this catalytic reactor showed the single-tandem controllable catalytic ability. The novel protocol not only provides a new solution to complicated catalytic processes but also inspires the further application of smart polymers in a broader spectrum of areas.

Obtaining and characterizing biochar from Eichhornia crassipes using a solar pyrolysis reactor prototype

[Introduction]: Latin America has extensive wetland areas of international importance, since these wetlands preserve wildlife, acting as a source and purifier of water; protecting us from floods, droughts, and other environmental disasters. However, these wetlands are threatened by eutrophication and aquatic weeds, such as the water lily in La Presa, La Vega, Jalisco, Mexico. [Objective]: The present investigation provides an alternative for the sustainable management of the water lily (Eichhornia crassipes) by obtaining biochar and its evaluation. [Methodology]: A functional prototype of a solar pyrolysis reactor was developed, running 36 tests to pyrolyze water lily samples with 17-23% humidity, applying a 5 in Hg vacuum at different temperatures (170, 200 and 230 ºC) and residence times (120, 150, 180 and 210 min); finding the best yield of biochar by the response surface method. [Results]: The optimal conditions in the reactor were found at 170 ºC, with a residence time of 171.8 min. The biochar presented a calorific value of 17.56 MJ/kg, 20.11 % by weight of fixed carbon and 6.89 C/H (carbon-hydrogen) ratio. [Conclusions]: This proposal provides evidence for a new solar pyrolytic reactor that processes water lily to produce high calorific biochar or to fix carbon, which could be a solution to one of the effects of eutrophication.