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We presented a control strategy for tablet manufacturing processes based on continuous direct compression. The work was conducted by the experts of pharmaceutical companies, machine suppliers, academia, and regulatory authority in Japan. Among different items in the process, the component ratio and blended powder content were selected as the items requiring the control method specific to continuous manufacturing different from the conventional batch manufacturing. The control and management of the Loss in Weight (LIW) feeder were deemed the most important, and the Residence Time Distribution (RTD) model were regarded effective for setting the control range and for controlling of the LIW feeder. Based on these ideas, the concept of process control using RTD was summarized. The presented contents can serve as a solid fundament for adopting a new control method of continuous direct compression processes in and beyond the Japanese market.

This work reports the effect of scaling up annular centrifugal contactors (ACCs) upon the residence time distribution and the efficiency of extraction of uranium. The experiments were carried out in a multi-scale ACC platform of three ACCs with rotor diameters of 12, 25, and 40 mm. To enable direct comparison across all three scales of ACC, the residence time distributions were acquired by injecting dye into the solvent phase at a constant relative volume related to the ACC liquid holdup. Across all scales and flowrates, there was little difference in residence time distribution (95%, and it improved further in larger rotor diameter ACCs.

This short communication presents residence time distribution (RTD) measurements and modeling in a 16 m3 Siemens flotation cell, as the first RTD characterization in an industrial-scale pneumatic cell. The Siemens cell was installed as a pre-rougher machine in a Cu-Mo selective plant. This plant recovered molybdenite as an enriched product, depressing copper-bearing minerals. Irradiated non-floatable solid and Br82 in water solution were employed as solid and liquid tracers, respectively. The tracers were instantly injected into the Siemens cell, and the inlet and outlet concentrations were directly measured by external non-invasive detectors. From the flotation literature, three model structures for the RTDs were evaluated, including perfect mixing, one large perfect mixer and one small perfect mixer in series (LSTS), and N perfectly mixed reactors in series. A transport delay was incorporated for all models. The LSTS representation was more consistent with the experimental data, showing that the Siemens cell RTDs presented significant deviations with respect to perfect mixing and plug-flow regimes. From the industrial measurements, mean residence times of 4.1–5.2 min were estimated.

[Display omitted] • A flow calorimeter capable of measuring spatial temperature profile is presented. • It offers a wealth of reaction dynamics data by detecting temperature in real time. • Hydrolysis of acetic anhydride is performed as a test reaction. • Spatially resolved temperature profiles are used to determine the rate constants. Continuous flow calorimeters are considered an emerging technique due to their ability to reduce safety issues associated with highly exothermic rapid reactions. In this study, a custom-made isoperibolic flow calorimeter was constructed, which uses a pyroelectric IR Sensor for temperature profile recording. The objective of this study is to validate the reactor concept for the determination kinetic parameters. Residence time distribution (RTD) analysis was conducted to assess the mixing performance of the packed-bed reactor employed in the calorimeter. This calorimeter was connected to a custom-made conductivity flow cell (CFC), to measure the in-line conductivity of the outlet stream. An axially dispersed plug flow reactor model (AD-PFR) is required to be able to incorporate the non-ideal behaviour of the flow. The experimental apparatus design and methodology was validated by conducting the hydrolysis of acetic anhydride. The activation energy, E A and the pre-exponential factor, ln(k 0) for the hydrolysis of acetic anhydride were found to be 52.05 kJ mol−1 and 12.26 (s−1), respectively, which falls within the range of reported values. The new flow calorimeter proved to be effective, and accurate. [ABSTRACT FROM AUTHOR]

• Characterization of fluorescent dye binding sites on antibodies. • Structure function analysis by mass spectrometry. • To have an inert tracer, minimal labeling is highly effective but not enough. • An inert tracer for determination of residence time distribution in chromatography. Fluorescently labeled antibodies are widely used to visualize the adsorption process in protein chromatography using confocal laser scanning microscopy (CLSM), but also as a tracer for determination of residence time distribution (RTD) in continuous chromatography. It is assumed that the labeled protein is inert and representative of the unlabeled antibody, ignoring the fact that labeling with a fluorescent dye can change the characteristics of the original molecule. It became evident that the fluorescently labeled antibody has a higher affinity toward protein A resins such as MabSelect Sure. This can be due to slight differences in hydrophobicity and net charge, which are caused by the addition of the fluorescent dye. However, this difference is eliminated when using high salt concentrations in the adsorption studies. In this work, the site occupancy of two labeled antibodies, MAb1 (IgG1 subclass) and MAb2 (IgG2 subclass) conjugated with the fluorescent dye Alexa Fluor™ 488 was elucidated by intact mass spectrometry (MS) and peptide mapping LC-MS/MS, employing a sequential cleavage with Endoproteinase Lys-C and trypsin and in parallel with chymotrypsin alone. It was shown that the main binding site for the dye was a specific lysine in the heavy chains of the MAb1 and MAb2 molecules, in positions 188 and 189 respectively. Other lysine residues distributed throughout the protein sequence were labeled to a lot lesser extent. The labeled antibody had a slightly different affinity to MabSelect Sure although its primary binding site (to Protein A) was not affected by labeling, despite the secondary region responsible for binding to the protein A was partly labeled. Overall, the fluorescent-labeled antibodies are a good compromise as an inert tracer in residence time distribution and chromatography studies because they are much cheaper than isotope-labeled antibodies; However, the differences between the labeled and unlabeled antibodies should be considered. [ABSTRACT FROM AUTHOR]

[Display omitted] • Particle mean retention times were estimated for forced-air-type mechanical flotation cells. • Theoretical and practical methods for the MRT predictions at four copper concentrators were considered. • A new equation was introduced for approximating MRT based on the industrial results. Mean residence time (MRT) in industrial flotation cells is one of the key parameters for kinetic modelling and identification of effective volumes. However, not all plants have access to robust tracer techniques to reliably measure this parameter with reasonable accuracy. For this reason, flotation practitioners estimate the mean residence time from the volumetric pulp flowrate and the effective cell volume. The latter requires assumptions on the air and froth volumes inside the machines, which has led to inaccuracies in MRT estimations. To overcome this challenge, the present communication correlated the measured (τ m) and calculated MRTs from the rougher circuits of four copper flotation plants (twenty-eight surveys). The rougher stages of these plants consisted of forced-air mechanical cells of 100, 160 and 200 m3. The correlation between the measured and calculated MRTs showed that the following equation can be used as an approach to predict the MRT in industrial forced-air flotation cells: τ m = α V f / Q , with α = 0.872 representing the relative effective volume (95 % confidence interval of 0.839–0.905), V f the total cell volume, and Q the volumetric feed flowrate of pulp. This interval for the relative effective volume is proposed as a reference range to consolidate current assumptions for cell sizing, or to revisit these assumptions in case of significant deviations regarding the observed interval. [ABSTRACT FROM AUTHOR]

The coiled tube geometry has different industrial applications whereby heating and cooling operations are required. In this work, a 2D semi-empirical model based on a straight tube is proposed to represent the 3D phenomena of flow and heat transfer in a coiled tube. The model considers a modified velocity profile based on residence time distribution (RTD) experiments and a heat transfer enhancement factor based on heating and cooling experiments. For testing and validating the model, experiments were performed using a Newtonian fluid (glycerin/water mixture) and a non-Newtonian fluid (carboxymethylcellulose CMC solution) at flow rates from 0.5 to 2.0 L/min in a coiled tube with 9 turns. The y -laminar RTD model was successfully adjusted to experimental E-curves and its parameter y was correlated with flow rate. Heating and cooling experiments with the coil provided outlet temperatures at different conditions of flow rate and temperature. The model was adjusted to match the outlet temperatures, providing the heat transfer enhancement factor F , the second empirical parameter of the model. This factor was linearly correlated with Reynolds number in a log-log plot and showed a threshold for negligible enhancement (F = 1). The model was numerically solved the finite difference method after a mesh dependency study. Good outlet temperature predictions were obtained with computational time of about 1 min, which is much smaller than usual computational times for a 3D coil geometry, and model provides velocity and temperature fields useful for further simulation of non-isothermal laminar flow reactors, such as bacterial inactivation in thermal processing of liquid foods. • 3D flow and heat transfer problem simplified to 2D representation. • Laminar velocity profile adjusted to mimic experimental residence time distribution. • Heat transfer enhancement factor introduced to mimic experimental heat load. • Model tested using two fluids in laminar flow (Newtonian and pseudo-plastic). • Model provides velocity and temperature fields, useful for non-isothermal reactors. [ABSTRACT FROM AUTHOR]

In continuous casting, it is common to close single or multiple submerged nozzles of multi-strands tundish to adapt to production rhythm due to insufficient liquid steel or equipment failure. However, the closure of the nozzle will change the flow field in the tundish and further affect the removal efficiency of inclusions in the tundish. For this reason, based on numerical simulation, the flow behavior of liquid steel and the removal of inclusion in tundish with different nozzle closed were studied, and the optimal nozzle closing scheme was obtained, which provided a basis for the selection of nozzle closing in tundish. At the same time, the gas curtain is set in the tundish to alleviate the negative effects such as the increase of dead zone caused by closing nozzle. The results show that the removal rate of inclusions with sizes 10, 30, 50, 70, and 90 μm change from 12.4%, 39.1%, 74.2%, 93.3%, and 95.6% to 14.7%, 36.4%, 76.4%, 85.3%, and 93.8%, respectively. The volume of the tundish dead zone is increased after closure of nozzle, the dead zone of the tundish is improved when the gas is installed, and the dead zone volume was reduced from 14.8% and 16.4% to 13.9 and 14.1%.

Lamellar settlers are widely used in solid separation due to their relative high surface area paired with a small tank volume. Settlers exposed to high load variations may change their settling properties based on the variation of the flow pattern. Applying the critical point theory and coherent structure concept, a flow topology analysis was performed with the help of computational fluid dynamic simulations. The compartments were determined by the fluid flow, and the dynamic behavior of the compartments was taken into account. Under normal diurnal load variation, the architecture of the compartments did not change, in contrast to the mass transport between the zones, whereas the sludge removal process made significant changes in the architecture. The results showed two main flow zones with significant internal recirculation in the first zone. The hydraulic surface loading was examined in each zone, and the study revealed that the actual hydraulic load could be from 1.5 to 4.5 times much higher than that in individual zones due to recirculation eddies in the reactor tanks. The design hydraulic loading rate did not consider the local flow pattern. The discrete phase model approximation provided acceptable results, and the extent of the recirculation zone changed stepwise with different loads.

The present work focuses on investigating the residence time behavior of microparticles in a concurrent downer reactor through experiments and numerical simulations. For the numerical simulations, a three-dimensional multiphase model was developed using the Euler-Lagrange approach. The experiments were performed in a 0.8 m-long steel reactor with gravitational particle injection. The effects of different operating conditions, e.g., the sheath gas velocity on the particle residence time distribution were assessed. An increase in the sheath gas flow rate led to a decrease in the peak residence time, although the maximum residence time increased. Regarding the lowest sheath gas flow rate, the particles' peak residence time was twice as high compared to the peak residence time within the highest flow rate. The particles' residence time curves presented a broad distribution coinciding with the size distribution of the powder. The numerical results agreed with the experimental data; thus, this study presents a numerical model for predicting the particle residence time behavior in a concurrent downer reactor. Furthermore, the numerical simulations contributed to a better understanding of the particle residence time behavior inside a concurrent downer reactor which is essential for optimizing thermal rounding processes. Dimensionless correlations for the observed effects are developed. [ABSTRACT FROM AUTHOR]

Using coal as feed material and sodium chloride (density and size same as high ash-containing particles in coal feed) as a tracer, residence time distribution (RTD) studies have been carried out in air table. Residence time of particles plays a key role pertaining to density wise segregation on air table. Parameters i.e. air flow rate, side tilt and vibration frequency have strong effect on residence time of particles on air table so their effect was studied using tracer technique. Experimentation was carried out and RTD curves were obtained to find the effect of said parameters on residence time of particles. The residence time of tracer particles increased and span time decreased with increase in the air flow rate, vibration frequency and side tilt. Simulating fundamental force balance equations, explanation of parameters effect on residence time was done. Using dispersion mathematical model, simulated RTD curve was calculated for low air flow rate and validated with the experimental results. [ABSTRACT FROM AUTHOR]

Investigation on the miniaturized parallel multichannel‐based devices packed with glass beads to improve the mass exchange execution is the critical focal point of the current study. One of the essential parameters to specify the miniaturized devices' flow distribution is the residence time distribution (RTD). In the present context, the RTDs of a liquid tracer were investigated for the air‐water multiphase flows (concurrent) across the multichannel‐based miniaturized devices (comprising of 11 similar dimensional parallel channels). The devices were variable in height and packed with glass beads. The conductivity estimations generated the RTD curves and were addressed by the axial dispersion model (ADM). The fluid‐flow rates differed within the range of 5–23 ml min−1. The axial dispersion coefficients and the rate of the specific energy dispersion were investigated. The effects of pressure difference and geometry on the hydrodynamic attributes and mixing properties were well‐illustrated, and the new correlations were suggested. [ABSTRACT FROM AUTHOR]

The molecular weight distribution (MWD) of polymers is a target of the optimization and control of industrial polymerization processes, as it dictates the processability and properties of polymers. A method, named as segment probability method, is developed to calculate the MWD of polycondensates produced by monomers of types A2 and B2 in a continuous reactor. It considers a growing chain as being composed of A and B segments in the middle of the chain and two terminal segments at the chain ends. It calculates the propagation probabilities of these different types of segments upon taking into account both the polycondensation and side reaction kinetics as well as the residence time distribution of the continuous reactor. The method is validated by poly(butylene terephthalate) (PBT) obtained from an industrial polymerization process composed of a continuous esterification reactor. The MWDs of the PBT calculated by this method are in agreement with those measured by size exclusion chromatography with mean square errors less than 10%. [ABSTRACT FROM AUTHOR]

Radiotracer‐based residence time distribution (RTD) measurements were performed for two identical wheat straw pulping digesters to evaluate and compare their performances. The radiotracer technetium (99mTc) as sodium pertechnetate was used to follow the liquid phase inside the digester. The product quality of both digesters was not identical for similar sets of operating conditions. Temperature, pressure, and mass flow rates were the influencing parameters, and the experimental and theoretical mean residence time (MRT) were compared. A significant amount of flow abnormalities was observed in the second digester as compared to the first one, including channeling, dead volume, scaling, and bypassing. The axial dispersion model and tank in series with the back‐mixing model were suitable for modeling the obtained RTD data. [ABSTRACT FROM AUTHOR]

While many studies have confirmed the effect of particle size distribution on the residence time in a reactor, the most employed models of continuous tank leaching process consider the residence time and particle size distributions as independent variables. In minerals processing field, no systematic study has been conducted on this issue yet. In this research, the relationship between the particles size and their residence time in a mixing tank has been studied. An empirical method for the determination of the residence time distribution function based on the inflow particles size distribution has been proposed. The relationship between the average size of one size fraction of particles and its residence time was obtained by mean residence time and parameter (an empirical coefficient). Results showed that increasing the particle sizes resulted in a 50% increase in the mean residence time while decreased from 0.95 to 0.3. Using the evaluated values of the residence time distribution function of the inflow stream was determined. Including this function in the segregated flow model, the effect of the variations of the value on the leaching performance was evaluated. Results showed that smaller values of resulted in higher conversion value. [ABSTRACT FROM AUTHOR]

Abstract The objective of the present study is to evaluate the fluid dynamics of a flotation column (2" in diameter and 6 m in height) based on gas hold-up measurements and, in particular, by applying the liquid-phase RTD (residence time distribution) technique. Additionally, a comparative study is performed between different methodologies used to determine RTD hydrodynamic parameters such as fitting of tanks-in-series and axial dispersion models to the experimental data. The evidence indicates that the axial dispersion and tanks-in-series models agreed well with the experimental data, with a slight advantage of the first model, in terms of obtaining the fluid dynamic parameters. It was proven that the axial dispersion model parameters (Pe or Nd) can be obtained with good precision (R2 > 0.99) within the evaluated ranges from correlations that use the number of tanks in series (N) values estimated by the tanks-in-series model.

This paper is the second in a series of two that describes the application of discrete element method (DEM) and reduced order modeling to predict the effect of disturbances in the concentration of drug substance at the inlet of a continuous powder mixer on the concentration of the drug substance at the outlet of the mixer. In the companion publication, small-scale material characterization tests, a careful DEM parameter calibration and DEM simulations of the manufacturing process were used to develop a reliable RTD models. In the current work, the same calibration workflow was employed to evaluate the predictive ability of the resulting reduced-order model for an extended design space. DEM simulations were extrapolated using a relay race method and the cumulative RTD was accurately parameterized using the n-CSTR model. By performing experiments and simulations, a calibrated DEM model predicted the response of a continuous powder mixer to step changes in the inlet concentration of an API. Thus, carefully calibrated DEM models was used to guide and reduce experimental work and to establish an adequate control strategy. In addition, a further reduction in the computational effort was obtained by using the relay race method to extrapolate results. The predicted RTD curves were then parameterized to develop reduced order models and used to simulate the process in a matter of seconds. Overall, a control strategy evaluation tool based on high-fidelity DEM simulations was developed using material-sparing small-scale characterization tests., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this work, a high-fidelity digital twin was developed to support the design and testing of control strategies for drug product manufacturing via direct compression. The high-fidelity digital twin platform was based on typical pharmaceutical equipment, materials, and direct compression continuous processes. The paper describes in detail the material characterization, the Discrete Element Method (DEM) model and the DEM model parameter calibration approach and provides a comparison of the system's response to the experimental results for stepwise changes in the API concentration at the mixer inlet. A calibration method for a cohesive DEM contact model parameter estimation was introduced. To assure a correct prediction for a wide range of processes, the calibration approach contained four characterization experiments using different stress states and different measurement principles, namely the bulk density test, compression with elastic recovery, the shear cell, and the rotating drum. To demonstrate the sensitivity of the DEM contact parameters to the process response, two powder characterization data sets with different powder flowability were applied. The results showed that the calibration method could differentiate between the different material batches of the same blend and that small-scale material characterization tests could be used to predict the residence time distribution in a continuous manufacturing process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

[Display omitted] • Archimedes tube crystallizer (ATC) promising continuous crystallizer concept. • Three-phase contact angle decisive for solid phase transport. • Ideal plug flow behavior of liquid and solid phase independent of parameters used. • Clogging of tubing preventable. • Flexible residence time in ATC due to no pressure drop limitation. Various continuous crystallizer concepts have been developed for the small-scale production (V ˙ ≤ 100 mL min−1) of APIs and fine chemicals. The existing concepts differ in terms of achievable residence times and residence time distribution (RTD) width and can be classified qualitatively in a portfolio on the basis of these characteristics. The classification demonstrates, that it is still challenging to achieve long, flexible residence times in combination with narrow RTD width leading to narrow particle size distributions. Thus, an air-segmented coiled tube crystallizer was developed based on the Archimedes screw principle: The Archimedes tube crystallizer (ATC). In this device, coiled tubing is employed to convey individual fluid batches by rotation. Thereby, the air-segmented flow is generated by a specifically designed inlet tank mounted on the rotational axis. As a first step towards the implementation of the ATC concept in industry, characterization experiments were focused in this work. In a Design of Experiment, liquid phase RTD with tracer sodium chloride/water and solid phase RTD with material system L -alanine/water were investigated. The experimental results proved narrow RTD close to ideal plug flow for both liquid and solid phase over the complete operating window. Hence, the ATC represents a reasonable expansion of the continuous crystallizer portfolio. [ABSTRACT FROM AUTHOR]

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Disposable food packaging accounts for a large proportion of the plastic waste in the environment. Bio‐based and biodegradable alternatives could help to reduce plastic pollution but must perform similarly to current synthetic materials. Here, we investigated the effect of two plasticizers (glycerol and sorbitol) on the mechanical and barrier properties of films composed of extruded pea protein isolate. We evaluated physical properties such as tensile strength, elongation at break, moisture content, surface energy, residence time distribution, and gas barrier properties as a function of plasticizer concentration. The flexibility and workability of the films generally increased with higher concentrations of the plasticizer. The residence time distribution (RTD) showed that sorbitol mixtures remained in the extruder longer than glycerol mixtures, exacerbating the loss of quality. Glycerol films generally retained more moisture than sorbitol films and the tensile strength declined with increasing glycerol content, but the elongation at break increased. The polar fraction of the surface energy increased with higher concentrations of sorbitol, indicating that sorbitol is more polar than the pea protein isolate. In terms of barrier properties, both the water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) were higher for films plasticized with sorbitol. Specifically, the OTR for sorbitol‐plasticized films at 50% (vol/vol) was 519 cm3*100 μm/(m2*d*bar) compared to 300 cm3*100 μm/(m2*d*bar) for the glycerol‐plasticized films, and the WVTR for sorbitol‐plasticized films at 50% (vol/vol) was 2633 g*100 μm/(m2*d) compared to 895 g*100 μm/(m2*d) for the glycerol‐plasticized films. For both plasticizers, the WVTR increased with increasing plasticizer concentration. In contrast, the OTR declined with increasing glycerol concentrations, whereas no trend was observed for sorbitol. Our study shows that pea protein isolate is suitable for the manufacture of bio‐based films and confirms that plasticizers influence the resulting mechanical and barrier properties. Further research is necessary to optimize the properties of the films. [ABSTRACT FROM AUTHOR]

Storage tanks are essential components of water supply systems to store water to face normal and emergency conditions and to level off required pressures. However, tanks can also be the source of water quality deterioration due to poor mixing and long residence times. In this paper, the effect of the tank configuration and of the operating mode on water mixing and renewal in cylindrical small-scale tanks of typical configurations is assessed. Results show that nearly complete mixing conditions can be attained in the tanks with inlet and outlet pipes located at opposite walls. Short-circuiting and the formation of dead zones is demonstrated in tanks with inlet and outlet pipes located close together. In fill-and-draw mode, water mixing is enhanced by a wide water-level variation, but renewal takes longer than in steady-state conditions. In addition, an empirical formula is proposed for estimating the turnover time in cylindrical tanks operated at a constant level. By identifying the configurations and operating conditions that promote mixing, this paper contributes to better water quality management in existing and new storage tanks in distribution systems. [ABSTRACT FROM AUTHOR]

[Display omitted] In this paper we present a thorough description of the digital twin development for a continuous pharmaceutical powder blending process in accordance with the Process Analytical Technologies (PAT) and Quality by Design (QbD) guidelines. A low-dosage system of caffeine active pharmaceutical ingredient (API) and dextrose excipient was examined via continuous blending experiments. Near infrared (NIR) spectroscopy–based process analytics were applied; quantitative evaluation of spectra was achieved using multivariate data analysis. The blending system was represented with mechanistic residence time distribution (RTD) models and two types of recurrent artificial neural networks (ANN), experimental datasets were used for model training or fitting and validation. Detailed comparison of the two modelling approaches, the optimization of the model-based digital twin, and efficiency of the soft sensor-based process monitoring is presented through several validating simulations. Both RTD models and nonlinear autoregressive neural networks demonstrated excellent predictive power for the low dosage blending process. RTD models can prove to be more advantageous in industrial development as they are less resource-intensive to develop and prediction accuracy on low concentration levels lacks dependency from the precision of chemometric calibration. Reduced material costs and limited development timeframe render the digital twin an efficient tool in technological development. [ABSTRACT FROM AUTHOR]

The present study identifies the hydraulic efficiency of a novel onsite sanitation system at variable hydraulic shock loading conditions. The system consisted of three chambers, each working as an up-flow anaerobic bioreactor, accommodated within a single unit. The hydraulic characteristics were identified with the help of residence time distribution (RTD) analysis by step feeding of lithium chloride (LiCl) solution into the system. The experiments were run at variable hydraulic loading conditions at different peak flow factors (PFF) of 1, 2, 4 and 6 while maintaining 24-h hydraulic retention time. As revealed in the RTD analysis, the biofilm reactor achieved a very good hydraulic efficiency that varied from 0.76 to 0.81 at PFF 1, 2 and 4. Although in the case of PFF6, it was comparatively low. It was noted that the dispersion number was always below 0.2 at variable hydraulic shock loading conditions under different PFFs, which indicated that the reactor behaved perfectly between mixed-flow and plug-flow reactor. The system was also able to achieve good pollutant removal efficiency for chemical oxygen demand (COD) and total suspended solids (TSS) under all PFFs, which was more than 68 and 75%, respectively. [ABSTRACT FROM AUTHOR]

The paper investigates the flow dynamic behaviour of inverse fluidized bed biofilm reactor (IFBBR) for the treatment of pharmaceutical based biomedical wastewater. The residence time distribution (RTD) study has been employed as a tool to investigate the flow dynamic behaviour of wastewater within the reactor. The biofilm reactor is operated using Pseudomonas fluorescens for various ratios of settled bed volume to reactor working volume (Vb/Vr) with different superficial air velocities and examined their impact on flow dynamics. The outcomes of this study demonstrate the presence of dead volume and short circuiting in the reactor were reduced for the optimized (Vb/Vr) ratio of 0.20 and optimum superficial air velocity (Ug)m of 0.220 m/s. The potential of IFBBR was experimentally validated by analysing the chemical oxygen demand (COD) removal efficiency, total dissolved solids (TDS) and total suspended solids (TSS) emanating from the wastewater. Findings of this study reveals that maximum COD reduction of about 92% was achieved when the reactor was operated with (Vb/Vr)m of 0.20 with superficial air velocity, Ugm of 0.220 m/s showing the optimal operating parameters for IFBBR which has good mixing and less back mixing condition inside the reactor. [ABSTRACT FROM AUTHOR]

In the petrochemical industry, separation of oil from water is a very important process. Wells produce mixtures of gas, oil, and water which undergo a primary stage of separation inside horizontal gravity separators. The performance of these vessels is evaluated by measuring mean residence time (MRT) and residence time distribution (RTD). Although many researchers studied flow characteristics in horizontal separators, limited number of articles exist that discuss separator MRT and RTD with varying water-cuts. In this article, the authors study an experiment using a horizontal gravity separator by previous researchers and perform computational fluid dynamics (CFD) simulations on the same geometry under similar conditions. The simulation results show qualitative agreement with the experiments by previous researchers. As shown by experiments before, CFD results showed that MRT of the organic phase increased with increase in water-cut. In addition, the RTD characteristics show very similar trends between CFD and experimental results.

The effect of material flow through a ball mill on the efficient production of particles was explored using the attainable region framework. The target efficiency was the production of floatable particles of size between 300 μm and 75 μm upon expending the lowest ball milling energy.To this end, a 3.2 m x 3.6 m ball mill in open circuit was assumed to process a feed of size less than 9.5 mm. A model of the milling circuit was then built for simulation under typical operating conditions. Feed flow-rates between 10 and 200 tph solids were simulated for several residence time distributions. First, the milling volume was set as a perfectly mixed reactor; then, gradually segmented into an increasing number of perfectly mixed reactors in series. The mass fraction of floatable particles in the product was monitored for the various combinations of operating conditions. The energy required to produce less than 300 μm particles was also estimated. Last, the collected simulation data was analysed using the attainable region and size-specific energy concepts.From the simulation results, it was found that the ball mill would produce -300 + 75 µm particles efficiently from a feed of size less than 9.5 mm at a rate of 75 tph. In terms of residence time distribution, milling performance hit a plateau once the number of perfectly mixed reactors in series reached 9 segments. Finally, it was shown that the throughput of the plug-flow milling reactor could be increased by 10% from the baseline of the perfectly-mixed mill. There may therefore be a motivation for the development of plug-flow-like milling technology.

A mathematical model for the prediction of internal recirculation of complex impinging stream reactors has been presented. The model constitutes a repetition of a series of ideal plug flow reactors and CSTR reactors with recirculation. The simplicity of the repeating motif allows for the derivation of an algebraic relation of the whole system using the Laplace transform. An impinging streams reactor system with one axial and two tangential inlet fluid streams was constructed and considered as a case study. The model predicts satisfactorily the complex and flow rate dependent experimental residence time distribution functions obtained employing a pulse tracer method for different total flow rates of the incoming feed. The variation of the controlling parameters with changing the total inlet flow rate is discussed. The presented model can predict complex internal recirculation streams within the impinging streams reactor system.

Slow pyrolysis of biomass is commonly performed in rotary kilns. The effect of the particle residence time distribution on biomass conversion is often neglected when numerically modeling such systems. But this effect might be significant under certain conditions.The data presented here are results of numerical simulation of the biomass pyrolysis in rotary kilns under numerous operating conditions and levels of axial dispersion of biomass particles. The varied operating conditions are the kiln diameter (D=0.1–1 m), the ratio of particle to kiln diameter (d/D=5×10−3–40×10−3), the ratio of kiln length to kiln diameter (L/D=1–10), the kiln’s inclination angle (β=0.1–8∘), the Froude number (Fr=10−3–10−2), the rotational Reynolds number (Re=102–16×103), and the Péclet number (Pe=5–100). Data of 13,851 single case simulations are provided with this article. This includes the mean particle residence time, gas, bed and kiln wall temperatures, solid and gaseous species mass flows, heat fluxes, and the solid bed height over the kiln length.These comprehensive data have the potential to help in modeling, design, analysis, and optimization of rotary kilns used for the pyrolysis of biomass.The main characterization and interpretation is presented in the related main research paper by Pichler et al. (2021)[1].

The hybrid upflow anaerobic sludge blanket reactor (HUASB) is a modified UASB wherein, inert media variants are used to prevent the biomass washout and its circular shape reduces biological and hydraulic dead zone. The flow pattern is crucial to facilitate hydraulic behavior as it has a direct effect on the microorganism-substrate utilization rate. So present study focuses on hydrodynamics of the HUASB reactors with different inert media viz. seashells (RA) and coconut husk fiber (RB). Tracer studies using a common dye (i.e. congo red) were performed in continuous mode for designed flow ranges from 600 to 1200 ml/hour to determine the hydrodynamic parameters and indices of mixing namely dispersion number (D/uL), peclet number (Pe), no. of reactors in series (N), morril dispersion index (MDI), index of short circuiting (Isc), index of mean retention time (Imean), index of modal retention time (Imodal) and index of average retention time (Iavg). The obtained results for both the reactors indicates the intermediate degree of dispersion seems to be best for max substrate conversion. According to the findings, both HUASB reactors is more closely to the arbitrary flow reactors.

In small-scale continuous crystallization, particle suspension and residence time distribution are critical factors determining operability and product quality. Here, the Taylor–Couette crystallizer stands out for its high flexibility. Its characteristic vortex structure intensifies local mixing, thus improving the suspension and simultaneously narrowing the residence time distribution, whereby these effects can be adjusted by operating and design parameters. However, the operating window is limited by the prerequisite of sufficient particle suspension. In this study, we investigated the suspension behavior and its impact on the attainable liquid phase residence time distribution and the flow regimes observed. For this purpose, the just-suspended rotation rate was visually determined for different design and operating parameters. A correlation was regressed from experimental data, showing that this rotation rate was mainly affected by the radius ratio of the rotor and stator. In addition, the liquid phase residence time distribution was measured by tracer experiments in regions of sufficient suspension, validating a correlation from the literature. With a combination of both correlations, the design parameters of the apparatus can thus be optimized according to the goal of, for example, a narrow residence time distribution in the suspended state.

This paper compares two deconvolution methodologies used to estimate residence time distributions (RTD) in industrial closed-circuit ball mills. Parametric and non-parametric deconvolution techniques were evaluated. Both techniques allowed for direct RTD estimates from inlet and outlet tracer measurements in the mills, with no need for mass balances nor assumptions to correct the effect of the tracer recirculation in the grinding circuits. Measurements of inlet and outlet concentrations were conducted by radioactive solid tracers and on-stream detectors. The parametric deconvolution was applied assuming the N-perfectly-mixed-reactors-in-series model, whereas the non-parametric deconvolution consisted of a constrained least squares estimation subject to non-negativity. The shapes of the estimated RTDs were consistent between these methodologies, showing mound-shaped distributions in all cases. From the parametric approach, mixing regimes described by 2–4 perfect mixers in series were observed, which indicated significant differences regarding perfect mixing. The mean (τmean) and median (τ50) residence times were more consistent with the RTD shapes when applying the parametric deconvolution. The non-parametric approach was more sensitive to noise, a disadvantage leading to mean residence times significantly higher than the median, and less consistent with the RTD locations. From the comparisons, the estimation strategies proved to be applicable in industrial closed-circuit ball mills. The parametric deconvolution led to better overall performances for τ50 = 1.7–8.3 min, given a suitable model structure for the RTDs.

The residence properties of gas-solid phases are important to the design and process optimization of a COREX shaft furnace. In this study, we investigated the gas-solid residence time distribution by using a coupled CFD-DEM model. The effects of the center gas supply device (CGD) on the average residence time, variance, and volume fraction of the gas and solid phases were analyzed. The results revealed that the average residence time, dispersed plug volume fraction, and well-mixed volume increased, while the variance and the dead volume fraction of the gas phase decreased for the shaft furnace with CGD. The average residence time and the dispersed plug volume fraction of the solid phase decreased in the shaft furnace with CGD. The dead volume fraction and well-mixed volume fraction increased with the introduction of CGD. [ABSTRACT FROM AUTHOR]

Solid mixing process plays a crucial role in evaluating the reaction performance of multiphase reactor. However, there still lacks the systematic research on solid mixing for the multistage circulating fluidized bed with enlarged sections. Solid mixing mechanism in a multistage riser is investigated numerically in this study. Some individual characteristics of solid mixing are found. It is shown by analyzing residence time distributions that solid mean residence time and the degree of solid dispersion increase with the increasing solid flux or the decreasing superficial gas velocity. Nevertheless, particle diffusion coefficient increases as solid flux decreases or superficial gas velocity increases. Moreover, the diffusion coefficient in enlarged sections decreases with the increasing height, which is contrary to the variations in traditional risers. Compared with the traditional riser, particle diffusion is weak, but overall solid mixing is enhanced in the multistage riser. Furthermore, two mixing patterns that gas-solid flow develops towards the plug-type flow in the center region of riser and the mixed-type flow in the enlarged section are identified. In addition, the dominant recirculation time of solids in the enlarged section is predicted as 1.5 s under examined cases. [Display omitted] • Solid recirculation affects solid residence time distribution. • Particle diffusion weakens along the height of the enlarged section. • Solid mixing pattern changes and overall solid mixing is enhanced. [ABSTRACT FROM AUTHOR]

Residence time distribution (RTD) experiments provide very important information about the performance of reactors. In the present work, RTD experiments were performed with varying recycle and recirculation rates to see their effect on mean residence time (MRT), flow bypassing and stagnant volume in the reactor. A computer program was developed to solve the model equations using fourth-order Runge–Kutta method. A low bypass flow (<5%) was observed from the experimental RTD curves obtained at different operating conditions. A change in the MRT from 1.2 to 1.8 h was observed at different recycle and recirculation rates. At maximum recycle and maximum recirculation, in the study ranges, a 37% stagnant volume (with exchange) was predicted. In the absence of recycle and recirculation, a 53% stagnant volume (with exchange) was predicted corresponding to the best fit of the experimental RTD data. [ABSTRACT FROM AUTHOR]

Wet granulation is a size enlargement process in which fine powders are agglomerated into larger granules via the presence of a liquid binder. Among various types and modes of granulation processes, twin-screw granulation is a popular continuous wet granulation technique. The typical residence time that powders spend in a twin-screw granulator are in the order of seconds, hence, the rigorous mixing of solid and liquid particles across particle sizes and equipment geometry becomes even more important. This study aims to improve the mechanistic understanding of the effect of process and screw parameters on the mixing dynamics inside a twin-screw granulator using dispersion coefficient as a key metric. The dispersion coefficient quantifies the dispersion and is directly proportional to the extent of mixing occurring inside the granulator. An analysis of the experimentally obtained dispersion coefficient is performed to understand the effect of key process and design parameters such as feed rate, screw speed, number of kneading elements and, stagger angle. A semi-mechanistic model that incorporates these parameters was developed to estimate and predict the dispersion coefficient. The model accurately predicts the dispersion coefficient values and the goodness-of-fit values (R2) for the test set and full data set were found to be equal to 0.920 and 0.932 respectively. This model was further tested by predicting the complete RTD curves using the predicted dispersion coefficients. The average goodness-of-fit value (R2) for the prediction of RTD curves for all the experimental runs was calculated to be equal to 0.698. [Display omitted] • Axial dispersion is the main cause of mixing inside a twin-screw granulator (TSG). • The effects of TSG process and design parameters on axial dispersion were studied. • First semi-mechanistic model to predict axial dispersion coefficient in a TSG. • Complete residence time distribution curves were predicted and analyzed. [ABSTRACT FROM AUTHOR]

Pharmaceutical production remains one of the last industries that predominantly uses batch processes, which are inefficient and can cause drug shortages due to the long lead times or quality defects. Consequently, pharmaceutical companies are transitioning away from outdated batch lines, in large part motivated by the many advantages of continuous manufacturing (e.g., low cost, quality assurance, shortened lead time). As chemical reactions are fundamental to any drug production process, the selection of reactor and its design are critical to enhanced performance such as improved selectivity and yield. In this article, relevant theories, and models, as well as their required input data are summarized to assist the reader in these tasks, focusing on continuous reactions. Selected examples that describe the application of plug flow reactors (PFRs) and continuous-stirred tank reactors (CSTRs)-in-series within the pharmaceutical industry are provided. Process analytical technologies (PATs), which are important tools that provide real-time in-line continuous monitoring of reactions, are recommended to be considered during the reactor design process (e.g., port design for the PAT probe). Finally, other important points, such as density change caused by thermal expansion or solid precipitation, clogging/fouling, and scaling-up, are discussed. [ABSTRACT FROM AUTHOR]

Residence time distribution modeling of integrated perfusion to capture process can elucidate the impact of product quality excursions and filter fouling on monoclonal antibody production. In this case study, a glycosylation inhibitor and fluorescently labeled antibody are applied to the continuous process to study protein quality modulation, perfusion filter fouling, and unit operation hold times. The unit operations were modeled as continuous‐stirred tank reactors and the residence time distribution of a small molecule glycan inhibitor and impact on glycosylation were characterized. A fluorescently labeled antibody was applied as a tracer molecule and confirmed the impact of packed cell volume and filter fouling. This study demonstrates how a biologics continuous process can be modeled and characterized through residence time distribution to ensure a robust, well‐understood process. [ABSTRACT FROM AUTHOR]

SARS‐CoV‐2, a novel coronavirus spreading worldwide, was declared a pandemic by the World Health Organization 3 months after the outbreak. Termed as COVID‐19, airborne or surface transmission occurs as droplets/aerosols and seems to be reduced by social distancing and wearing mask. Demographic and geo‐temporal factors like population density, temperature, healthcare system efficiency index and lockdown stringency index also influence the COVID‐19 epidemiological curve. In the present study, an attempt is made to relate these factors with curve characteristics (mean and variance) using the classical residence time distribution analysis. An analogy is drawn between the continuous stirred tank reactor and infection in a given country. The 435 days dataset for 15 countries, where the first wave of epidemic is almost ending, have been considered in this study. Using method of moments technique, dispersion coefficient has been calculated. Regression analysis has been conducted to relate parameters with the curve characteristics. [ABSTRACT FROM AUTHOR]

Solids residence time distribution (RTD), which reflects the degree of solids mixing in bubbling fluidized bed (BFB), has become an essential parameter for the evaluation of reactor performances. In this paper, a modified structure‐based drag model was established to investigate the effect of the bed size and the correlation of bubble dimension on the gas‐solids hydrodynamics and solids RTD in three different scales of BFB. The result obtained from the modified structure‐based drag model shows better agreement with the experimental values and it can be used to predict the RTD properly. The deviation of flow field will cause a large difference in the RTD prediction. An accurate flow field is a prerequisite for calculating the RTD. For the cases of Geldart B particles, the Darton correlation is the best choice for low gas velocities. When scaling up a BFB, the RTD calculated by the modified structure‐based drag model is reduced in comparison with the experimental value, which is related to the increase of the bed size and the excessive estimation of the bubble size. On the other hand, the lack of consideration for the friction on both front and back walls in 2D simulation may lead to the over‐prediction of particle velocity and result in the deviation between calculated and experimental RTD value. [ABSTRACT FROM AUTHOR]

Continuous powder mixing technology (CMT) application during continuous direct compression has emerged as a leading technology used in the development and manufacture of solid oral dosage forms. The critical quality attributes of the final product are heavily dependent on the performance of the mixing step as the quality of mixing directly influences the drug product quality attributes. This study investigates the impact of blend material properties (bulk density, API particle size distribution) and process parameters (process throughput, hold up mass and impeller speed) on the mixing performance. Mixing of the blend was characterized using the Residence Time Distribution (RTD) of the process by trending the outlet stream of the mixer using a near-infrared (NIR) probe after the injection of a small mass of tracer at the inlet stream. The outcomes of this study show that the RTDs of the mixer with throughput ranging between 15 and 30 kg/h; impeller speed ranging between 400 and 600 rpm and hold up mass (HUM) ranging between 500 and 850 g can be described by a series of two ideal Continuous Stirred Tank Reactors (CSTRs) with different volumes, and correspondingly, different mean residence times. It is also observed that the mixing is mainly occurring in the lower chamber of the CMT and the normalized RTDs of the mixer are similar across the range of process conditions and material attributes studied. The results also showed that the formulation blend with different API particle sizes and bulk properties, like bulk density and flowability, provide insignificant impact on the mixing performance. The CMT allows independent selection of target set points for HUM, impeller rotational speed and line throughput and it shows great robustness and flexibility for continuous blending in solid oral dose manufacturing. [ABSTRACT FROM AUTHOR]

[Display omitted] Residence time distribution (RTD) method has been widely used in the pharmaceutical manufacturing for understanding powder dynamics within unit operations and continuous integrated manufacturing lines. The dynamics thus captured is then used to develop predictive models for unit operations and important RTD-based applications ensuring product quality assurance. Despite thorough efforts in tracer selection, data acquisition, and calibration model development to obtain tracer concentration profiles for RTD studies, there can exist significant noise in these profiles. This noise can make it challenging to identify the underlying signal and get a representative RTD of the system under study. Such concerns have previously indicated the importance of noise handling for RTD measurements in literature. However, the literature does not provide sufficient information on noise handling or data treatment strategies for RTD studies. To this end, we investigate the impact of varying levels of noise using different tracers on measurement of RTD profile and its applications. We quantify the impact of different denoising methods (time and frequency averaging methods). Through this investigation, we see that Savitsky Golay filtering turns out to a good method for denoising RTD profiles despite varying noise levels. The investigation is performed such that the key features of the RTD profile (which are important for RTD based applications) are preserved. Subsequently, we also investigate the impact of denoising on RTD-based applications such as out-of-specification (OOS) analysis and RTD modeling. The results show that the degree of noise levels considered in this work do not significantly impact the RTD-based applications. [ABSTRACT FROM AUTHOR]

Photocatalytic fuel cell (PFC) systems can be a new generation of energy production by simultaneously producing electricity and removing organic pollutants from aqueous solutions. A baffling photoreactor is developed for application in a PFC, and the continuous system consists of a light-responsive photoanode (ZnO/Bi 2 MoO 6 /MIL-101; ZnO/Bi 2 MoO 6 ; ZnO) and a photocathode (Cu/CuO/Cu 2 O). A response surface method (RSM) is presented to characterize the process factors (pH, immobilized catalyst dosage (mg/cm2), and tetracycline concentration (ppm)) on the performance of a reactor designed to optimize degradation efficiency and maximum power generation. The optimal conditions are determined at pH = 7, Catalyst dosage = 0.87 mg/cm2, and tetracycline concentration = 80 ppm. In optimal conditions, other parameters for degradation efficiency (88.8%), open circuit voltage (1.03 V), short circuit current (2.5 mA/cm2), and maximum power generation (0.87 mW/cm2) are obtained. The performance of different photoanodes by linear sweep voltammetry shows a current density of 2.5 mA/cm2 for ZnO/Bi 2 MoO 6 /MIL-101, which is 7.8 and 1.8 times higher than ZnO and ZnO/Bi 2 MoO 6 photoanodes, respectively. The flow regime is determined by residence time distribution (RTD) in the novel reactor with the experimental data of 6 tanks-in-series. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Substrate equalization theory and the index of cumulative overload were proposed. • Nitrogen removal performance was increased by optimizing influent patterns. • Residence time distribution and computer fluid dynamics verified the flow patterns. • Substrate and sludge are mixed more evenly as the cumulative overload decreases. • The new substrate equalization theory was verified via flow tests and simulations. To improve nitrogen removal efficiency (NRE) and achieve homogenous distribution of anammox sludge and substrate, a new substrate equalization theory and a cumulative overload index was proposed for multifed upflow anaerobic sludge bed (MUASB) reactors with mature anammox granules. The performance and flow patterns of MUASB reactors were investigated under various influent conditions. The results showed that the nitrogen removal performance and stability of MUASB reactors could be optimized by minimizing the cumulative load. The NRE gradually increased from 83.3 ± 2.2 %, 86.8 ± 4.2 % to 89.3 ± 4.1 % and 89.7 ± 1.6 % in feeding flow tests and feeding port tests, respectively. Furthermore, the flow patterns were compared based on residence time distribution and computational fluid dynamics, indicating that a better equilibrium distribution of microorganisms and substrates could be achieved in the MUASB reactors under the lowest cumulative load. Therefore, substrate equalization theory can be used to optimize the nitrogen removal performance of MUASB reactors with low-carbon footprints. [ABSTRACT FROM AUTHOR]

Microreactors have been successfully applied to execute a broad range of biotransformations in flow. However, microreactors have typically been designed with a specific biotransformation or a specific biocatalyst immobilization method in mind, constraining their wider applicability. Furthermore, their design is typically either applicable for whole-cell or for enzyme biocatalysis, but not for both. We present a novel microreactor design which offers cartridge-like insertion of both immobilised enzymes and cells. A T-shaped lid opens and closes the reaction chamber (whilst leaving the rest of the microreactor unchanged), enables the easy insertion of immobilised biocatalysts, and thus allows the user to configure different reactor types. We demonstrated this novel concept showing three different reactor types: a hydrogel microreactor containing entrapped E. coli cells overexpressing transketolase (volumetric productivity of 2.23 ± 0.83 mmol l -ERY L void 1 min 1), a packed-bed microreactor containing commercial beads with immobilised Candida antarctica lipase B (volumetric productivity of 317.69 ± 96.74 mmol BB L void 1 min 1), and a micropillar microreactor containing surface-immobilised ω-transaminase (volumetric productivity of 0.08 ± 0.02 mmol ACP L void 1 min 1). The proposed design showed consistency and robustness for 10 consecutive T-shaped lid 'open and close' cycles and withstood the pressure of at least 4 bar. Design analysis further included Computational Fluid Dynamics models and Residence Time Distribution measurements. The presented design offers a standardised approach for multiple applications, underpinning process development and paving the way for off-the-shelf microreactor technology for biocatalysis. [Display omitted] • Cartridge-like insertion of immobilised biocatalyst into microreactor. • One microreactor for different immobilisation supports. • Demonstrated three reactor types with one microreactor design. • Standardisation for off-the-shelf microreactor technology.. [ABSTRACT FROM AUTHOR]

The motion of dust particles significantly affects the service life and filtration efficiency of filter elements. By employing a coupled computational approach combining Computational Fluid Dynamics and Discrete Element Method (CFD-DEM), the Johnson-Kendall-Roberts (JKR) model was incorporated into the calculation of adhesive forces between particle-particle and particle-wall interactions. The influence of the membrane layer on dust particle deposition and detachment on the surface of filter elements was investigated through simulation analysis. The influence of membrane layers on the deposition and detachment of dust particles in filter elements was investigated. The results show that the addition of the membrane layer led to a 35.5% increase in the initial filtration pressure drop of the filter. However, it concurrently resulted in a diminution of the deposition depth of dust particles. By the eighth cycling period, the deposition depth of the filter element with membrane (FWM) was 2.5 mm, which was only half that of the filter element without membrane (FOM). Moreover, it was found that the cleaning efficiency of the FOM is more sensitive to reverse flow pressure, while the cleaning efficiency of the FWM is more sensitive to the duration of pulse width. These findings can help explain the mechanism of dust particle deposition and detachment and provide a basis for the design and manufacturing of filter elements. [Display omitted] • Bonding model to fabricate the support body and porous membrane. • Membrane layer increased particle quantity and concentrated its spatial distribution. • The residence time distribution of residual particles exhibits a parabolic profile. • Presents a method for analyzing the motion of particles within filter elements. [ABSTRACT FROM AUTHOR]

This study investigated the potential of rapeseed protein as a novel alternative protein source in meat analogs produced by extrusion cooking technology. To study the substitutability of rapeseed protein to soybean protein, the addition ratios of rapeseed protein to soybean protein in the extrusion experiment were 0:50, 10:40, 20:30, 30:20, 40:10 and 50:0 (w/w), respectively. The results showed that adding 0–20% rapeseed protein not only decreased the specific mechanical energy and mass flow rate of the mixture during extrusion, but also enhanced the hardness and chewiness of the extrudates while reducing their elasticity and resilience. In addition, increasing the amount of rapeseed protein may lead to decreased expansion characteristics, internal pore structure, and water absorption rate of the extrudates, as well as a decrease in brightness and an increase in redness on the surface. Weibull model could well describe the rehydration behavior for dynamic fitting of the extrusion rehydration process. Moreover, with the increase of rapeseed protein substitution, the content of disulfide bonds, and the proportion of relatively ordered protein secondary structures with high stability increased, and the degree of protein denaturation decreased. Besides, the degree of starch gelatinization reduced and the thermal stability of extrudates improved. Interaction analysis indicated that disulfide bonds are the primary force maintaining protein-mediated interactions in the extrudates. The incorporation of rapeseed protein shortened the mean residence time of molten feedstock and shifted the flow state to plug flow. Overall, our investigation suggests that within low levels of addition (≤20%, w/w), rapeseed protein has the potential to partially substitute for the soybean protein-based textured proteins. High substitution levels or complete substitution are not feasible due to the relatively low expansion and rehydration rates. [Display omitted] • The properties of the extrudates with 20% rapeseed protein are acceptable. • Low hydration and gelation of rapeseed protein decrease extrudate expansion rate. • Weibull model can fit the rehydration process of extrudates well. • Rapeseed protein shortens the residence time and mixing degree during extrusion. [ABSTRACT FROM AUTHOR]