Hybrid Reactor Research Articles

The Effects of Photobioreactor Type on Biomass and Lipid Production of the Green Microalga Monoraphidium pusillum in Laboratory Scale

Mass production of microorganisms, algae among them, for new bioactive compounds and renewable innovative products is a current issue in biotechnology. The greatest challenge of basic research on this topic is to find the best solution for both physiology and scalability. In this study, the main goal was to highlight the contradictions of physiological and technological optimization in the same, relatively small, laboratory scale. The green alga Monoraphidium pusillum (Printz) Komárková-Legnorová was cultured in a conventional Erlenmeyer flask (as air bubbled in a tank-type photobioreactor) and in a hybrid (fermenter type + helical tubular type) photobioreactor of the same volume (2.8 L). Higher cell numbers from 1.7–2.3-fold, 2–2.8-fold higher dry masses, and 1.9–2.6-fold higher total lipid contents (mg·L−1) were measured in the tank reactor than in the hybrid reactor. Cultures in the conventional tank reactor were characterized with better nutrient utilization (42.8–77.7% higher phosphate uptake) and more diverse lipid composition than in the hybrid reactor. The study highlights that well-scalable arrangements and settings could be not optimal (or unsuitable in some cases) from a physiological point of view. The results suggest certain developmental directions for complex, well-scalable devices and highlight the importance of testing the gained physiological optima on these systems.

Hydrogen and Methane Production from Tequila Vinasses in a Novel Hybrid Reactor Containing Biofilm and Suspended Biomass

Hydrogen and Methane Production from Tequila Vinasses in a Novel Hybrid Reactor Containing Biofilm and Suspended Biomass

Effect of the Aeration Strategy on NOB Suppression in Activated Sludge and Biofilm in a Hybrid Reactor with Nitrification/Denitrification

The purpose of the study was to analyse the impact of aeration strategies defined by the changes in the duration of aerated sub-phases, the ratio between non-aerated and aerated sub-phase times (R), and dissolved oxygen concentrations (DO) on the suppression of nitrite-oxidizing bacteria (NOB) in activated sludge and biofilm developing in a hybrid reactor with nitrification/denitrification. The primary factor causing NOB suppression both in biofilm and in activated sludge was an increase in the R-value (from 0 to 1/4 and from 1/4 to 1/3). After reducing the DO from 3 to 2 mg O2/L, there were no changes in the frequency of NOB occurrence, and no reduction in the nitrite oxidation rate was recorded. The abundance of Comammox bacteria was considerably affected by the change from continuous to intermittent aeration. Activated sludge showed a substantial increase in the quantity of clade A and B, whereas the quantity considerably decreased in biofilm.

Аналитическое моделирование топливного цикла термоядерных и гибридных реакторов

The characteristic fuel cycle (FC) schemes for fusion and hybrid (fusion-fission) reactors are considered. The FC structures of the facilities that are under construction and of newly designed ones are analyzed. The FC architecture general features and specific ones of each facility are highlighted. Two simplified FC schemes are proposed, and a computer program for solving a system of differential equations and simulating the accumulation of fusion fuel component (tritium) in FC systems in a steady-state operation mode of the facilities has been developed. The obtained results are compared with published calculations for the DEMO, SABR, and DEMO-FNS facilities. The computer codes used for numerical simulation of the fusion reactor FCs are reviewed; a high relevance of the problem being solved is shown, and proposals for further sophistication of the developed model are formulated.

Аналитическое моделирование топливного цикла термоядерных и гибридных реакторов

The characteristic fuel cycle (FC) schemes for fusion and hybrid (fusion-fission) reactors are considered. The FC structures of the facilities that are under construction and of newly designed ones are analyzed. The FC architecture general features and specific ones of each facility are highlighted. Two simplified FC schemes are proposed, and a computer program for solving a system of differential equations and simulating the accumulation of fusion fuel component (tritium) in FC systems in a steady-state operation mode of the facilities has been developed. The obtained results are compared with published calculations for the DEMO, SABR, and DEMO-FNS facilities. The computer codes used for numerical simulation of the fusion reactor FCs are reviewed; a high relevance of the problem being solved is shown, and proposals for further sophistication of the developed model are formulated.

Stability of Polymeric Membranes to UV Exposure before and after Coating with TiO2 Nanoparticles.

The combination of photocatalysis and membrane filtration in a single reactor has been proposed, since the photocatalytic treatment may degrade the pollutants retained by the membrane and reduce fouling. However, polymeric membranes can be susceptible to degradation by UV radiation and free radicals. In the present study, five commercial polymeric membranes were exposed to ultraviolet (UV) radiation before and after applying a sol–gel coating with TiO2 nanoparticles. Membrane stability was characterized by changes in hydrophilicity as well as analysis of soluble substances and nanoparticles detached into the aqueous medium, and by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometry (EDS) for structural, morphological, and elemental distribution analysis, respectively. The TiO2 coating conferred photocatalytic properties to the membranes and protected them during 6 h of UV radiation exposures, reducing or eliminating chemical and morphological changes, and in some cases, improving their mechanical resistance. A selected commercial nanofiltration membrane was coated with TiO2 and used in a hybrid reactor with a low-pressure UV lamp, promoting photocatalysis coupled with cross-flow filtration in order to remove 17α-ethinylestradiol spiked into an aqueous matrix, achieving an efficiency close to 100% after 180 min of combined filtration and photocatalysis, and almost 80% after 90 min.

Concept development and candidate technologies selection for the DEMO–FNS fuel cycle systems

Within the framework of activities on a pilot industrial hybrid reactor (pilot hybrid plant-PHP) development, the DEMO–FNS fusion neutron source is being designed in Russia. Russian fusion and fission community considers it as the main facility developing prospective nuclear technologies, which should update the results of the ITER researches in the field of physics and control of burning plasma. Progress in the development of the plant and simulations of the fusion fuel cycle allows starting the engineering design of basic fuel cycle systems. In this paper, we consider the new prospective of technological solutions for the tokamak fuel cycle. The possibility of their integration and the analysis of the technology readiness level for them in the Russian Federation are addressed as well. The code simulating the hydrogen isotope flows in a tokamak was significantly upgraded for evaluation of the specific technological solutions as well as for combined modeling of the fuel circulation in the core and divertor plasmas allowing for the pumping, processing, and fuel isotope content control in the plasma. The article describes the core and divertor plasma model used for the calculations and shows the D/T fuel throughput values, which should be provided by the fuel injection systems (NBI and pellets). The dependencies of the HFS and LFS pellet injection frequency necessary for the main plasma supply and ELM control are found for different core and divertor plasma parameters. For the DEMO–FNS core plasma, an operating window has been found in terms of fueling control parameters. It was shown that D and T throughputs of 40–50 Pa·m3 s−1 should be provided by the fuel injection systems (NBI and pellets) to maintain the fusion power up to 40 MW. For the DEMO–FNS core plasma, an operating window defined by the particle confinement times and fuel injection throughputs has been found.

Benzophenone and Diethyl Phthalate Removal from Real Wastewater by a Multi-stage Hybrid Reactor

Benzophenone and Diethyl Phthalate Removal from Real Wastewater by a Multi-stage Hybrid Reactor

Efficiencies of anaerobic hybrid and UASB reactors to alleviate the adverse effect of elevated salinity in wastewater

AbstractBACKGROUNDUntreated high‐strength salinity wastewaters pose a serious threat to the environment. Anaerobic treatment is an effective process with double advantages of waste stabilization and energy production. However, high organic compound and sodium toxicity in high‐salinity wastewaters adversely affect the performance of anaerobic treatment. In this study, anaerobic hybrid (AH) and upflow anaerobic sludge blanket (UASB) reactors were investigated for their efficiencies to alleviate the negative effects of high‐salinity wastewater.RESULTSDouble increases in the NaCl concentration drastically deteriorated the performances of both reactors. The activities of acetoclastic methanogens (ACM) and hydrogenotrophic methanogens (HTM) in both reactors decreased to 22–28% and 36–40% compared to the previous period, respectively. However, the methanogen population (Methanosarcinales and Methanobacteriales) was not affected negatively. The AH reactor exhibited excellent performance during the recovery and restart periods, which only required 7 days to complete the recovery period. Furthermore, during the restart period, the AH reactor showed high chemical oxygen demand (COD) removal efficiency, methane (CH4) production and yield as ≈90%, 2600 mL day−1 and 0.30 m3 CH4 kg−1 CODremoved, respectively. The rate of biomass washout from the AH reactor also was lower compared to the UASB reactor. The concentration of attached biomass in the packed zone of the AH reactor gradually increased indicating the growth of an active microbial biofilm.CONCLUSIONThe excellent performance of the AH reactor was presumably a result of its packed zone configuration which provided the supporting media to entrap smaller microbial aggregates, reduce biomass washout and support the growth of active biofilm. © 2021 Society of Chemical Industry (SCI).

Transmutation Investigation of a Typical VVER-1000 Reactor Burnup Products to less Toxicity Isotopes in a Fusion-Fission Hybrid Reactor

Transmutation of burnup products for a typical VVER-1000 reactor in a fusion-fission hybrid reactor has been investigated using MCNPX 2.6.0 calculation code. Burnup calculation of a fission reactor was performed for a 1000 MW practical power of a VVER reactor core using UO2 fuel and light water as its coolant and moderator, as well. The burnup products have been classified and separated according to their half-lives and their usages, and the remaining wastes were used as fuels for a fusion-fission hybrid reactor. The burnup calculation was also implemented for the fission wastes of the mentioned hybrid reactor, and the remaining products were separated and classified. The results showed that fission products can be transmuted into useful elements or to elements with less toxicity (with the decrement of activity) and less mass, and according to the IAEA toxicity limit of nuclear wastes, the levels of radioactivity and toxicity decreased. The results confirmed appropriately “the waste transmutation capability” of a fusion-fission hybrid reactor.

First proof of concept for full-scale, direct, low-temperature anaerobic treatment of municipal wastewater

Municipal wastewater constitutes the largest fraction of wastewater, and yet treatment processes are largely removal-based. High-rate anaerobic digestion (AD) has revolutionised the sustainability of industrial wastewater treatment and could additionally provide an alternative for municipal wastewater. While AD of dilute municipal wastewater is common in tropical regions, the low temperatures of temperate climates has resulted in slow uptake. Here, we demonstrate for the first time, direct, high-rate, low-temperature AD of low-strength municipal wastewater at full-scale. An 88 m3 hybrid reactor was installed at the municipal wastewater treatment plant in Builth Wells, UK and operated for 290 days. Ambient temperatures ranged from 2 to 18 °C, but remained below 15 °C for > 100 days. Influent BOD fluctuated between 2 and 200 mg L-1. However, BOD removal often reached > 85%. 16S rRNA amplicon sequencing of DNA from the biomass revealed a highly adaptable core microbiome. These findings could provide the basis for the next-generation of municipal wastewater treatment.

Impact of operational conditions on methane yield and microbial community composition during biological methanation in in situ and hybrid reactor systems

BackgroundBiogas can be upgraded to methane biologically by adding H2 to biogas reactors. The process is called biological methanation (BM) and can be done in situ in a regular biogas reactor or the biogas can be transferred to a separate ex situ upgrading reactor. The hybrid BM concept, a combination of in situ and ex situ BM, has received little attention, and only a few studies have been reported. The hybrid BM has the advantage of resolving the issue of pH increment during in situ BM, while the size of the ex situ BM reactor could be reduced.ResultsIn this study, the efficiency of in situ and hybrid biological methanation (BM) for upgrading raw biogas was investigated. The hybrid BM system achieved a CH4 yield of 257 mL gVS−1 when degrading a feedstock blend of manure and cheese waste. This represented an increase in methane yield of 76% when compared to the control reactor with no H2 addition. A 2:1 H2:CO2 ratio resulted in stable reactor performance, while a 4:1 ratio resulted in a high accumulation of volatile fatty acids. H2 consumption rate was improved when a low manure–cheese waste ratio (90%:10%) was applied. Furthermore, feeding less frequently (every 48 h) resulted in a higher CH4 production from CO2 and H2. Methanothermobacter was found to dominate the archaeal community in the in situ BM reactor, and its relative abundance increased over the experimental time. Methanosarcina abundance was negatively affected by H2 addition and was nearly non-existent at the end of the experiment.ConclusionsOur results show that hybrid BM outperforms in situ BM in terms of total CH4 production and content of CH4 in the biogas. In comparison to in situ BM, the use of hybrid BM increased CH4 yield by up to 42%. Furthermore, addition of H2 at 2:1 H2:CO2 ratio in in situ BM resulted in stable reactor operation.

Recovery of methane dissolved in the effluent of a novel upflow anaerobic hybrid reactor (UAHB) submitted to temperature variation

ABSTRACT Recent studies point out losses of 30–40% of the produced methane in the effluent of anaerobic reactors treating sewage, reducing the renewable energy potential and the environmental footprint. A novel bench-scale upflow anaerobic hybrid (UAHB) reactor combining a sludge blanket at the bottom and a filter media at the top, both with three-phase separators, was proposed to evaluate the recovery of dissolved methane. UAHB was operated with volumetric organic loading rate of 1.24 kg COD m−3 d−1 and hydraulic retention time of 8 h for 218 days to evaluate the influence of temperature (18°C, 23°C, and 28°C) in the methane dissolved in the effluent and collected from three-phase separators. Chemical oxygen demand (COD) and total suspended solids (TSS) removals efficiencies remained constant during the operation and equal to 90 and 95%, respectively, related to the activity of biomass retained in the filter media. Temperature increase influenced more the methane production in the sludge blanket rather than in the upper bed. The volume of recovered methane increased about 20% with the installation of the support media and the upper three-phase separator (3PHS). The loss of methane dissolved in the effluent was strongly influenced by the temperature, and higher with the decrease of this parameter. Non-statistically significant correlations were observed between the temperature and the methane production in the upper bed (p-value = 0.0943) and total (p-value = 0.0930). Thus, it can be concluded that the evaluated temperatures did not influence the global efficiency and the total methane yield of the UAHB reactor.

Hybrid hydrogel reactor with metal–organic framework for biomimetic cascade catalysis

It has always been a goal for immobilized enzymes to work under their native conformational states while possessing robust stabilities in harsh environments. Hydrogel is a promising enzyme matrix because of its cell-like microenvironment and porous internal structure to preserve the conformations of enzymes, maximizing catalytic efficiency. However, the challenges in low chemical tolerance and poor mechanical strength remained. Herein, a unique organic/inorganic hybrid hydrogel system was fabricated through the interfacial mineralization of metal–organic frameworks (MOFs) on hydrogel microsphere for processing biomimetic cascade reaction. The combination of hydrogel and MOFs layer is synergistic. The porous hydrogel network offers a biocompatible space for encapsulated enzymes to eliminate their undesirable restriction and chemical interactions with hosts, allowing the enzymes to work under native states for benefiting high activity, while the inorganic MOFs layer protects the enzymes from harsh environments to endow the hybrid reactor with robust stabilities. Attractively, a high enzyme tolerance against polar organic solvents was approached in the hybrid reactor. In addition, by the spatial arrangement of different enzymes in inner hydrogel and outer MOFs layer, the hybrid reactor can also function as a multi-compartmental structure for performing incompatible enzyme reactions to give distinguished reaction fluxes and product outputs, as occurred in natural cells.

Evaluation of concentrated solar thermal energy for iron ore agglomeration

The iron and steelmaking industry is actively seeking to reduce its overall carbon footprint with major research and investment directed towards fossil fuel-free steelmaking. In this paper, we present a novel iron ore agglomeration process that produces a Lime Magnetite Pellet (LMP) feed using concentrated solar flux as the energy source that significantly reduces the CO2 emissions compared to existing pellet making processes. The process has been tested under laboratory experiments inside a solar simulator-electric furnace hybrid reactor setup. A detailed mass and energy balance analysis of the process was conducted for estimation of the emission reduction as well as for estimating the solar flux requirement at various percentages of fuel to solar flux substitution. The preliminary economics of the solar-based LMP process was also investigated. The estimated capital cost of a 2 Mtpa (million tonnes per annum) plant was between AU$165 M and AU$142 M assuming a solar reactor thermal efficiency of 50% and 80%, respectively. The payback period was likely to be 15–20 years (50% efficiency) and 7–9 years (80%). At current achievable reactor efficiencies, a solar-based LMP process is not economically attractive. However, with further development in reactor design, heliostat cost reductions and improvements in thermal storage performance, a solar-based LMP process could potentially be commercialised.

Strategies for Fast Fission Matrix Estimation with Fuel Temperature and Control Rod Feedback

Monte Carlo methods are useful for simulating new reactor designs, but even with advances in computing, these methods still require a significant amount of time to perform transient or multiphysics calculations coupled with thermal modeling. This work demonstrates a hybrid reactor physics method that uses Monte Carlo to precalculate an initial database of fission matrix parameters, then combines these results for fast calculations on arbitrary system states. This paper extends previous work that demonstrated these methods on the Penn State Breazeale Reactor (PSBR). Approaches for reducing time and memory cost and increasing the accuracy in reproducing Monte Carlo output are considered. For modeling fuel temperature, a representative temperature distribution is used while tallying the initial fission matrix database. Different approaches for modeling the coupling between individual control rod insertions as well as control and fuel temperature effects are presented as well. Individual solutions are completed in less than 1 s on a single core, and error with respect to Monte Carlo is within 35 pcm for multiplication factor, 0.6% root-mean square, and 2.8% maximum for the normalized three-dimensional fission source distribution on critical, steady-state configurations. Further qualification on different reactor types is needed, but the simplicity and flexibility of this method make further development promising.

Evaluating the performance of anaerobic moving bed bioreactor and upflow anaerobic hybrid reactor for treating textile desizing wastewater

Performance and kinetic analysis of anaerobic moving bed bioreactor (AnMBBR) and upflow anaerobic hybrid reactor (UAHR) were investigated for the treatment of synthetic textile desizing wastewater (TDW) under organic loading rate (OLR) of 0.6–12 kgCOD/m3/day at thermophilic temperature (55 °C). The effects of increase in temperature (from 35 to 55 °C) on anaerobic treatment efficiency were studied. In the kinetic study for COD removal, first order substrate removal, Grau second order and modified Stover-Kincannon models were applied. By increasing temperature from 35 °C to 55 °C, COD removal, volumetric biogas production and methane content were increased 1.22, 2.58 and 1.08 times in AnMBBR. Whilst in the case of UAHR the increment for the aforementioned parameters were 1.10, 2.51 and 1.10 times, respectively. By increasing OLR from 0.6 to 6 kgCOD/m3/day, above 60% and 70% COD removal was observed, while the biogas increased from 0.12 to 0.97 L/L.day and 0.13–1.22 L/L.day for AnMBBR and UAHR, respectively. Up to an optimum OLR (6 and 8 kgCOD/m3/day for AnMBBR and UAHR) volumetric biogas production was also increased, simultaneously. Grau second order and modified Stover-Kincannon were found to be the best fit models (R2 =0.99). Biogas production and methane content in biogas were comparatively better in the case of real textile desizing wastewater due to lower sulfate concentration in the feed.

Critical insights into psychrophilic anaerobic digestion: Novel strategies for improving biogas production

Anaerobic digestion (AD) under psychrophilic temperature has only recently garnered deserved attention. In major parts of Europe, USA, Canada and Australia, climatic conditions are more suited for psychrophilic (<20 ℃) rather than mesophilic (35 – 37 ℃) and thermophilic (55 – 60 ℃) AD. Low temperature has adverse effects on important cellular processes which may render the cell biology inactive. Moreover, cold climate can also alter the physical and chemical properties of wastewater, thereby reducing the availability of substrate to microbes. Hence, the use of low temperature acclimated microbial biomass could overcome thermodynamic constraints and carry out flexible structural and conformational changes to proteins, membrane lipid composition, expression of cold-adapted enzymes through genotypic and phenotypic variations. Reduction in organic loading rate is beneficial to methane production under low temperatures. Moreover, modification in the design of existing reactors and the use of hybrid reactors have already demonstrated improved methane generation in the lab-scale. This review also discusses some novel strategies such as direct interspecies electron transfer (DIET), co-digestion of substrate, bioaugmentation, and bioelectrochemical system assisted AD which present promising prospects. While DIET can facilitate syntrophic electron exchange in diverse microbes, the addition of organic-rich co-substrate can help in maintaining suitable C/N ratio in the anaerobic digester which subsequently can enhance methane generation. Bioaugmentation with psychrophilic strains could reduce start-up time and ensure daily stable performance for wastewater treatment facilities at low temperatures. In addition to the technical discussion, the economic assessment and future outlook on psychrophilic AD are also highlighted.

The methanogenic archaea characteristics and efficacy of aerobic waste sludge in the start-up of anaerobic hybrid reactors treating cassava wastewater

Inoculum is a crucial factor influencing the success of an anaerobic digester start-up. This study evaluated the efficacy of aerobic waste activated sludge (WAS) to start-up anaerobic hybrid reactors (AHR) treating cassava wastewater. The start-up performance and stability of five 6.2 L AHRs inoculated differently by WAS (AHR1) and WAS co-inoculated with pig manure (AHR2), cow dung (AHR3), chicken manure (AHR4), and anaerobic pond sludge (AHR5) were investigated. The results depicted the potential of WAS as starter seed for AHR's start-up. This sludge contained methanogenic populations, mainly Methanomicrobials, Methanosarcinales, and Thermoplasmatales, for 1.5 × 107 MPN/g VS compared to 4.0 × 103-6.0 × 107 MPN/g VS in manures and anaerobic sludge. Co-inoculation of WAS with cow dung (AHR3) and anaerobic sludge (AHR5) promoted a rapid start-up, achieved 4.0 kg COD/m3.d within 1.5-1.7 months, while about 2.5-3.3 months needed for the others. A satisfying performance, stability, microbial development and activity, depicted as high COD removal (CODrem) efficiency and methane productivity, were achieved in all digesters. About 0.32 and 0.21 m3/kg CODrem for biogas and methane yielded in AHR1, whereas 0.41-0.49 m3-biogas/kg CODrem and 0.25-0.32 m3-CH4/kg CODrem obtained in other reactors. This finding confirmed that inoculum's quality is critical for productive gas productivity and system stability maintenance.

Modeling of the Isomerization and Separation Process of para‐Xylene in a Moving Bed Reactor

AbstractSimulated moving bed reactors (SMBRs) are hybrid reactors that perform reaction and separation processes simultaneously in a single unit. Their high separation performance and ability to overcome equilibrium constraints on the reaction make them effective in a wide range of equilibrium reactions. This study investigated an SMBR for xylene isomerization and separation of p‐xylene from other xylene isomers (free of ethylbenzene) in the liquid phase. The effects of operating variables including temperature, switching time, and columns arrangement on the performance parameters and optimal conditions were determined. Due to the removal of products from the reaction site, the SMBR drives the chemical equilibrium toward producing more product than a conventional reactor under the same conditions.