Correlation Analysis of Radical Polymerization Reactor Operating Conditions to Industrial Scale Swelling Capacity of Superabsorbent

A main subject to be considered when an extension of the burnup of Light Water Reactor fuel is discussed, is the water/steam corrosion of the Zircaloy fuel cladding material under reactor operation and hypothetical accident conditions. Here it is pointed out that Zircaloy corrosion under normal reactor operation conditions increases as function of burnup at least linearly. Relying on the function of the cladding wall as a first barrier against fuel and fission product release to the environment a suitable rod design should take into account – besides corrosion under normal LWR operation conditions – an additional loss of wall thickness by steam oxidation in case of a hypothetical loss-of-coolant accident. This aspect has been verified by high temperature measurements of Zircaloy oxidation kinetics and creep-rupture behavior under isothermal and temperature-transient conditions in steam.

17 - Rheology Control

Polymerization reactor modeling: A review of recent developments and future directions

Integrating biomass and waste into high-pressure partial oxidation processes: Thermochemical and economic multi-objective optimization

The development of polymer resins can benefit from the application of neural networks. The aim of this paper is to present how neural networks can help deal with the development of new resins, starting from the end user properties to set up the reactor's operating conditions. The procedure presented in this paper consists of a network that predicts the operating conditions of the reactor with maximum error of 2%. New resins can be developed and the reactor's operating conditions can be set in a much faster way, reducing the number of experiments and pilot plant tests, and hence, time and money spent on development.

Summary form only given, as follows. A self-consistent two-dimensional radio-frequency glow discharge model has been developed in cylindrical coordinates using a fluid model. The objective of the study is to provide insights to charged species dynamics and investigate their effects on deposition process for a polyatomic depositing gas discharge. Swarm data as a function of electron energy for methane are provided as input to the model. A power-law scheme is used for the discretization of convection-diffusion terms in the model. The necessary dc bias for the discharge in the asymmetric reactor geometry is predicted by a trial-and-error method such that the cycle-averaged current to the powered electrode becomes zero. The simulations are performed for different experimental design and operating conditions. The model predictions of electron density profile and self-generated dc bias compared well with the experimental results. Comparisons were first made with the data obtained by Sugai and coworkers from Nagoya University, Japan. Computations were carried out for the same geometry and operating conditions of the experimental reactor to obtain the radial and axial variations of plasma variables. The contours of cycle averaged electron and positive ion densities are shown. The present model was used to simulate a second experimental reactor (with a different geometric configuration) at Chemical Vapor Deposition Laboratory, Drexel University. The model predictions of electron density, dc bias and power compared well with the experimental measurements. The validated model was then used to predict the temporal and spatial variations of plasma variables for different reactor operating conditions. The radial variations of species fluxes to the cathode are also presented at different operating conditions of the reactor as they are important for thin carbon film deposition process.

The efficiency of fermentation reactors is significantly impacted by gas dispersion and concentration distribution, which are influenced by the reactor's design and operating conditions. As the process scales up, optimizing these parameters becomes crucial due to the pronounced concentration gradients that can arise. This study integrates the kinetics of the fermentation process with hydrodynamic analysis using Bayesian optimization to efficiently determine the optimal reactor design and operating conditions. By utilizing computational fluid dynamics (CFD) simulations, the study provides a comprehensive assessment of distributions ranging from gas supply to cell growth. The results demonstrate that a combination of wide baffle width, narrow impeller gap, slow gas flow rate, and high agitation speed significantly enhances reactor performance by improving gas distribution and minimizing stagnant zones. These findings underscore the importance of considering both kinetic and hydrodynamic factors to achieve more precise and scalable fermentation processes, offering valuable insights for industrial applications.

Influence of tubular reactor structure and operating conditions on dry reforming of methane

Polymerization reactor type and operation conditions have a marked influence on polymer properties such as distribution of molecular weight, chemical composition, and particle size. Due to the very nature of polymeric.chains, if the synthesized polymer does not have the desired properties when exiting the reactor, it is very difficult and costly to improve its properties by further processing and purification, since most fractionation methods that are economically viable for small molecule compounds will fail for macromolecules [1,2].

Isotopic evidence for nitrous oxide production pathways in a partial nitritation-anammox reactor

Inverse modeling applications in emulsion polymerization of vinyl acetate

High-velocity fluidized bed reactors

Particle suspension reactors for solar water splitting can be an economical alternative to photovoltaic-driven electrolysis. One design resembles Nature’s Z-scheme where two photosystems work in concert to drive overall water splitting. A conceptual Z-scheme reactor has been reported where two compartments on the meter length scale are adjoined side-by-side, each containing photocatalyst particles that drive one half-reaction of overall water splitting, and are connected by a nanoporous material that allows mixing of the liquid electrolyte.1,2 Electronic charge is mediated between the compartments by a dissolved redox shuttle that undergoes oxidation or reduction at the particles. While this design facilitates product separation (i.e. separation of H2 and O2) and therefore circumvents formation of an explosive mixture of gases, active transport of the redox shuttle over these distances has been projected to account for about half of the capital cost of the reactor.1,2 Our team is evaluating the feasibility of new reactor designs where the compartments are stacked vertically. This generates a true tandem light-absorbing reactor where the theoretical maximum solar-to-hydrogen conversion efficiency is ~50% larger than a side-by-side or single light-absorber design. Because the compartments are expected to be ~10 cm tall, this design greatly decreases the distance required for redox shuttle transport therefore reducing or even eliminating the need for forced convection. In my presentation I will report on our team’s progress on this design. We used finite-element numerical methods to model and simulate in two dimensions the transient mass transport processes, light absorption, and electrochemical kinetics in the proposed reactor. The developed model provided insights into the influence of the reactor geometry and operating conditions on the overall performance. The Beer–Bouger–Lambert law was applied to obtain the spatial light-intensity field and volumetric reaction rates were obtained by coupling solid-state photodiode expressions with Butler–Volmer kinetics on the surface of the particles. Model results suggested that a reactor operating at a ~1% solar-to-hydrogen conversion efficiency can operate for greater than half a year without complete loss of redox shuttle at any location in the reactor. Experimentally, we investigated materials over many size scales, from single particles (~10 nm in diameter) to mesoporous thin films (~10 µm thick) to laboratory-scale prototype particle-suspension reactors (on the scale of feet). On the single particle level we used bipolar electrodeposition to create Janus-type particles consisting of model carbon particles with metal and metal-oxide electrocatalysts for H2 evolution and O2 evolution at the poles. We also jammed and covalently bound TiO2 nanoparticles into a single nanopore in a plastic sheet, wetted the particles with liquid electrolyte on both sides, and measured photovoltages that resulted from excitation of few particles. We also synthesized, characterized, and evaluated the photo(electro)chemical performance of BiVO4 and Rh-doped SrTiO3 nanocrystallites as mesoporous thin films and particles in model reactors, and evaluated the transport properties of several redox shuttles. Collectively, our efforts represent strides toward achieving a high-level of techno-economic viability in solar water splitting reactors. Acknowledgments: This work was supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Fuel Cell Technologies Incubator Program under Award No. DE-EE0006963 and Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231.

In this research batch reactors were operated with coffee processing waste and autochthonous microbial consortium, and a taxonomic and functional analysis was performed for phase I of stabilization of maximum H2 production and for phase II of maximum H2 consumption. During phase I, the reactor's operating conditions were pH 4.84 to 8.18, headspace 33.18% to 66.82%, and pulp and husk from 6.95 to 17.05g/L. These assays continued for phase II, with initial pH conditions of 5.8-8.1, headspace of 33.18-66.82%, and pulp and husk remaining from phase I. The highest homoacetogenesis was observed in assay 5 with pH 7.7, 40% headspace, and 15g/L of pulp and husk (initial concentrations of phase I). A relative abundance of Clostridium 41%, Lactobacillus 20% and Acetobacter 14% was observed in phase I. In phase II, there was a change in relative abundance of 21%, 63%, and 1%, respectively, and functional genes involved with autotrophic (formyltetrahydrofolate synthase) and heterotrophic (enolase) homoacetogenesis, butanol (3-hydroxybutyryl-CoA dehydrogenase), and propionic acid (propionate CoA-transferase) were identified. This study provides a new and amplified insight into the physicochemical and microbiological factors, which can be used to propose adequate operational conditions to maximize the bioenergy production and reduce homoacetogenesis in biological reactors.

This study was undertaken (i) to investigate the interactions of the activated sludge microbial community in a chemostat with the “environment”, such as the substrate composition and variations, (ii) to investigate how these interactions affect the quality of the treated effluent and (iii) to determine the limits or applicability conditions to the indicators and to the prediction potential of the treated effluent quality. This work presents (a) the experimental results obtained from a reactor fed municipal wastewater (Data Set2-DS2) concerning the reactor's operating conditions and the microbial community of the sludge (b) comparisons between DS2 and an older Data Set (DS1) obtained when the reactor was fed synthetic substrate, all other experimental conditions being identical, and (c) simulation results and sensitivity analyses of two model runs (R1 and R2, corresponding to DS1 and DS2). The first trophic level (P1) of the DS2 microbial community consisted of bacteria, the second trophic level (P2) of bacteria-eating protozoa, rotifers and nematodes and the third trophic level (P3) of carnivorous protozoa and arthropods. Rotifers were an important constituent of the DS2 microbial community. The DS1 and DS1 communities differed in total size, trophic level sizes and species composition. Correlations between the major microbial groups of DS2 community and either loading rates or effluent quality attributes were generally low, but the correlation of bacteria with SVI and ammonia in the effluent was better. Also, the ratio of rotifers to protozoa in P2 was correlated to BOD in the effluent. The results of this work indicate that predictions of the treated effluent quality based only on protozoa may not be safe. Sensitivity analysis of R2 run indicate that, when variation in Y and Kd biokinetic coefficients of the sludge are combined with fluctuations in composition and quality of municipal wastewater entering the reactor, then sufficient significant prediction of bacteria in the aeration tank is not possible. In order to avoid erroneous oversimplifications regarding phenomena taking place in the sludge and to understand “unexplained” process failures, more ecologically sound methods for studying wastewater treatment (WWT) processes are needed, since WWT are primarily ecosystems interacting with technological systems.