Scale-up Factor Research Articles

Dimensional-analysis and similitude for scale-up of solid-liquid extraction of Eurycoma longifolia roots

A dimensionless model was proposed to scale-up the solid-liquid extraction of Eurycoma longifolia roots. ShSc−1 dimensionless number was found to be the best fit of all proposed models. At optimum conditions of the extraction process, which were duration of extraction of 53 min, solvent to raw material ratio of 12.5:1 and roots particle size of 0.5 to 1.0 mm, the extract yield of 8.76% at lab-scale produced ShSc−1 no. of 0.0312. Employing the scale up rule of P/V idem and scale-up factor of 7.65, the extract yield of 8.65% with 1.37% error was obtained at pilot-scale at ShSc−1 no. of 0.0376. The outcome of this study provided useful scale-up knowledge in ensuring smooth transition from lab-scale to pilot-scale.

Heap Leach Production Modeling: a Spreadsheet-Based Technique

A variety of modeling techniques can be utilized to forecast metal production at heap leaching operations. These approaches reflect a wide range of complexity, flexibility, time to implement, cost, and accuracy. For many operators, a spreadsheet-based modeling technique is attractive since the calculations are directly accessible, models can often be developed by site staff, and the results are generally easy to extract and interpret. The authors have developed a spreadsheet-based modeling technique that provides a high degree of flexibility, while still considering detailed operating information for ore properties, leach kinetics, scale-up factors, lift height, and in-heap metal inventories. The technique involves establishing kinetic leach curves for each ore type to characterize metal extractions, followed by application of separate metal recovery curves to define the rate at which leached metals exit the heap in pregnant solution, taking into account delays due to the in-heap solution inventory. At any point in time, the difference between total metal extracted and total metal recovered is equal to the in-heap inventory of the leached metal. This modeling technique is particularly useful for larger multi-lift heaps where delays in metal recovery are appreciable due to in-heap solution holdup. The technique is also applicable to sites with multiple heaps, leach cycles, and/or metal recovery plants (e.g., carbon columns for gold; solvent extraction for copper). This paper describes the modeling technique, including input data required and methods for defining kinetic leach curves and metal recovery curves. The technique is compared against an alternative spreadsheet technique using a simplified in-heap solution inventory calculation to forecast metal production, which has proven to be effective at a number of sites.

Evaluation of Inter-Apparatus Separation Method Transferability in Countercurrent Chromatography and Centrifugal Partition Chromatography

In the countercurrent chromatography and centrifugal partition chromatography, separation method transfer and scale-up is often described as an easy and straightforward procedure. Separation methods are usually developed on lab scale columns and subsequently transferred using linear scale-up factors to semi-preparative or preparative columns of the same column design. However, the separation methods described in the literature have been developed on various columns of different design and size. This is accompanied by differences in the separation behavior of the columns and therefore makes separation method transfer difficult. In the current study, the separation performances of different columns were evaluated and compared. Linear correlations of stationary phase retention and column efficiency as a function of flow rate were found to be applicable for the calculation of separation resolution in the typical operating range of each column. In this context, a two-point short-cut approach for a fast column characterization is recommended. This allows a quick prediction of the separation method transferability between columns, which saves experimental time and effort. In the current study, the transferability between five different columns from lab scale countercurrent chromatography (CCC) (18 mL) to semi-preparative centrifugal partition chromatography (CPCs) (250 mL) with different cell numbers and design is investigated.

Electrodeposition of poly and nanocrystalline Cu-In-Se absorbers for optoelectronic devices

ABSTRACTCoupling semiconductors with electrochemical processes can lead to unusual materials, and attractive, practical device configurations. This work examines the reaction mechanism for single-step electrodeposition approach that creates device quality copper-indium-selenide (CISe) films with either polycrystalline or nanocrystalline morphologies on Cu and steel foils, respectively. The polycrystalline CISe film grows from In3+/Se4+ solution on Cu foil as Cu→ CuxSe→ CuInSe2; it may be used in standard planar pn devices. The nanocrystalline CISe film grown from Cu+/In3+/Se4+ solution follows the CuSe(In)→ CuInSe2→ CuIn3Se5 sequence. The latter approach leads to naturally ordered, space-filling nanocrystals, comprising interconnected 3-dimensional network of sharp, abrupt, p-CISe/n-CISe bulk homojunctions with extraordinary electro-optical attributes. Sandwiching these films between band-aligned contact electrodes can lead to high performance third generation devices for solar cells, light emitting diodes or photoelectrodes for fuel cells. Both approaches produce self-stabilized CISe absorbers that avoid recrystallization steps and can be roll-to-roll processed in simple flexible thin-film form factor for easy scale-up.

연구기반 스핀오프 창업기업의 중견기업으로의 성장요인 연구 - 콜마비앤에이치㈜ 사례 중심으로 -

연구기반 스핀오프 창업기업의 중견기업으로의 성장요인 연구 - 콜마비앤에이치㈜ 사례 중심으로 -

Numerical and analytical prediction of pressure and impulse from vented gas explosion in large cylindrical tanks

This paper presents an extension of previous study on estimating the internal and external pressure and impulse from vented gas explosion in large cylindrical tanks. Unlike the small-medium scale explosion from cylindrical tanks in previous work, explosion pressure and impulse from large-scale explosions are numerically and analytical investigated in this study. CFD simulations are conducted and validated by using experimental data. Sensitivity study on grid selection for large-scale explosion simulations is performed. By adopting two scale-up factors for the analytical correlations, the internal pressure and external pressure on adjacent tanks from vented gas explosion in a tank are accurately predicted. Parametric study of the effectiveness of separation gap between adjacent tanks on pressure and impulse mitigation is also carried out. Influences of the venting size, tank diameter and tank height on the effectiveness of separation distance for pressure and impulse mitigation from large-scale vented gas explosion in an adjacent tank are studied.

Achieving Sustainability and Scale-Up of Mobile Health Noncommunicable Disease Interventions in Sub-Saharan Africa: Views of Policy Makers in Ghana.

BackgroundA growing body of evidence shows that mobile health (mHealth) interventions may improve treatment and care for the rapidly rising number of patients with noncommunicable diseases (NCDs) in sub-Saharan Africa (SSA). A recent realist review developed a framework highlighting the influence of context factors, including predisposing characteristics, needs, and enabling resources (PNE), for the long-term success of mHealth interventions. The views of policy makers will ultimately determine implementation and scale-up of mHealth interventions in SSA. However, their views about necessary conditions for sustainability and scale-up remain unexplored.ObjectiveThis study aimed to understand the views of policy makers in Ghana with regard to the most important factors for successful implementation, sustainability, and scale-up of mHealth NCD interventions.MethodsMembers of the technical working group responsible for Ghana’s national NCD policy were interviewed about their knowledge of and attitude toward mHealth and about the most important factors contributing to long-term intervention success. Using qualitative methods and applying a qualitative content analysis approach, answers were categorized according to the PNE framework.ResultsA total of 19 policy makers were contacted and 13 were interviewed. Interviewees had long-standing work experience of an average of 26 years and were actively involved in health policy making in Ghana. They were well-informed about the potential of mHealth, and they strongly supported mHealth expansion in the country. Guided by the PNE framework’s categories, the policy makers ascertained which critical factors would support the successful implementation of mHealth interventions in Ghana. The policy makers mentioned many factors described in the literature as important for mHealth implementation, sustainability, and scale-up, but they focused more on enabling resources than on predisposing characteristics and need. Furthermore, they mentioned several factors that have been rather unexplored in the literature.ConclusionsThe study shows that the PNE framework is useful to guide policy makers toward a more systematic assessment of context factors that support intervention implementation, sustainability, and scale-up. Furthermore, the framework was refined by adding additional factors. Policy makers may benefit from using the PNE framework at the various stages of mHealth implementation. Researchers may (and should) use the framework when investigating reasons for success (or failure) of interventions.

Computational analysis of performance deterioration of a wind turbine blade strip subjected to environmental erosion

Wind-turbine blade rain and sand erosion, over long periods of time, can degrade the aerodynamic performance and therefore the power production. Computational analysis of the erosion can help engineers have a better understanding of the maintenance and protection requirements. We present an integrated method for this class of computational analysis. The main components of the method are the streamline-upwind/Petrov–Galerkin (SUPG) and pressure-stabilizing/Petrov–Galerkin (PSPG) stabilizations, a finite element particle-cloud tracking method, an erosion model based on two time scales, and the solid-extension mesh moving technique (SEMMT). The turbulent-flow nature of the analysis is handled with a Reynolds-averaged Navier–Stokes model and SUPG/PSPG stabilization, the particle-cloud trajectories are calculated based on the computed flow field and closure models defined for the turbulent dispersion of particles, and one-way dependence is assumed between the flow and particle dynamics. Because the geometry update due to the erosion has a very long time scale compared to the fluid–particle dynamics, the update takes place in a sequence of “evolution steps” representing the impact of the erosion. A scale-up factor, calculated in different ways depending on the update threshold criterion, relates the erosions and particle counts in the evolution steps to those in the fluid–particle simulation. As the blade geometry evolves, the mesh is updated with the SEMMT. We present computational analysis of rain and sand erosion for a wind-turbine blade strip, including a case with actual rainfall data and experimental aerodynamic data for eroded airfoil geometries.

Microfluidic Extractive Crystallization for Spherical Drug/Drug-Excipient Microparticle Production

Granulation is a common manufacturing step for pharmaceutical drug products, which improves powder flowability, compactibility, and ensures tablet content uniformity. Granules of uniform content can conventionally be challenging to obtain due to powder segregation and mixing issues prior to granulation. Spherical crystallization—a method where drug crystals are directly formed into spherical granules—is a promising way to overcome issues with mixing and form granules with uniform content. However, a common challenge of existing quasi emulsion solvent diffusion or solvent extraction methods for spherical crystallization involving miscible solvents in stirred batch vessels is the coarse control over particles sizes, as they are sensitive to multiple scale-up factors (mixing efficiency, impeller and vessel geometry, inlet configuration). This limits the method in terms of content uniformity, which in turn limits the extent to which granules with tunable dissolution profiles can be created. Here, we propose a...

Scalability of 3D printed structured porous milli-scale reactors

This study addresses the scalability of in-house designed, and 3D printed structured porous reactors for liquid-liquid reactions. The base structure of these porous reactors consists of cylindrical fibres in defined geometrical arrangements. Their scale-up was realized by increasing the reactor diameter by a factor of 1.5 and 2 respectively while keeping the fibre dimensions constant. Also, the effect of altering the fibre dimensions in proportion to the scale-up factor was assessed. The reactors were characterized in terms of their biphasic heat and mass transfer properties. In stratified flow, the scaled-up structured porous reactors exhibited high interfacial mass transfer coefficients (kLa) at residence times <10 s, whereas in Taylor flow an overall drop in kLa values was observed. Furthermore, the highest biphasic heat transfer coefficients were found for the structured porous reactors with a scale-up factor of 1.5. Moreover, the structured porous reactors were applied to industrially relevant reactions. For the oxidation of nonanol, the scaled-up reactors showed an overall drop in yield, nevertheless with two folds production rate at same pressure drop. For the relatively slow C-N cross-coupling reaction, larger yields were realized by arranging scaled-up reactors in series at same total residence time. Specifically, an arrangement of 8 reactors with a scale-up factor of 2 in series resulted in six times higher production rate than a conventional packed-bed reactor but without any additional pressure drop. For the considered range of residence times, keeping the fibre dimensions constant while increasing the reactor diameter was observed to be advantageous.

Improved Understanding of Cefixime Trihydrate Reactive Crystallization and Process Scale-up with the Aid of PAT

Reactive crystallization to make cefixime trihydrate crystals via cefixime disodium reacting with hydrogen chloride was investigated using ATR FTIR and an online imaging instrument with the aim of developing an improved understanding of the operation and condition optimization and scale-up. The operation involves times of continuing introduction of aqueous HCl solution into a cefixime disodium solution in water and also periods at which HCl was stopped for breeding of crystals. The concentration profile of the reactant cefixime disodium monitored by ATR FTIR being almost constant in the first 30–40 min since the start of introduction of HCl suggests that cefixime disodium (cefixime2–) reacts with HCl to form cefixime sodium (cefixime1–) first, prior to the formation of solids. Online imaging, off-line SEM image analysis, and XRD analysis revealed that spherical amorphous solids were formed first; the solids were then aggregated, followed by phase transition on the surface of aggregates to well-shaped crystals. The causal relationship between the process conditions and the size, impurity content, crystallinity, and whiteness of the cefixime trihydrate crystals was also investigated. It was found that the solution pH value at the time at which introduction of the first portion of HCl solution was stopped to begin breeding crystals has a major impact on both the size and the whiteness of the crystals. High pH value favors smaller crystals with a sharp white appearance. The length of the crystal breeding time was found to be critical to the crystallinity. Explanation of the observed phenomena and an operational envelope were defined. The size distribution, whiteness, impurity content, and crystallinity of cefixime trihydrate crystals were satisfactory as long as the operation was kept within the defined envelope. The experiments were conducted on a 2 L reactor, then successfully scaled-up to 50 and 4000 L in industry after having considered the scale-up factor in stirrer rotation speed.

Experimental investigations on tetrahydrofuran – methane – water system: Rapid methane gas storage in hydrates

This study reports methane (CH4) gas storage capacity along with TetraHydroFuran (THF) as guest molecules in mixed hydrates. This process has been studied in two reactors of 100 and 400 mL capacity, having 4.5 and 7.5 cm internal diameter respectively, in non-stirred configuration. Experiments were conducted in each reactor at constant initial gas pressure (7.5 MPa) and by increasing the height of the solution from 1 to 8 cm, resulting in volume scale-up factor of 5. The total CH4gas uptake (moles) passes through a maximum at around 50% volume of the reactor indicating a transition from gas-rich to solution rich conditions. Observed variations in gas uptake are within ±20% of the maximum, upon different solution volume from 35% to 70% of reactor’s volume. Another set of experiments were conducted keeping the amount of the solution constant and increasing gas pressure in the range of 0.5–11.0 MPa. The gas uptake increased upon an increase in the gas pressure, but this is at least 40% less compared to the theoretical estimate. The stirring of solution or addition of promoter (Sodium Dodecyl Sulfate, SDS) is also not effective in increasing the gas consumption. Kinetics of gas uptake, in both stirred and non-stirred conditions, are quicker and 90% of gas consumption occurs in an hour after the hydrate nucleation event.

Predictive model for the scale-out of small channel two-phase flow contactors

In this paper, double manifolds are theoretically investigated for the scale-out of two-phase incompressible flows in small channels. Statistical descriptors are proposed to characterise the maldistribution of the total flow rate and the ratio of the flow rates in the two-phase channels, based on the variances and covariance of the flow rates of the two fluids. A novel resistance network model is developed that relates the flowrates of the fluids in the two-phase channels to the hydraulic resistances of the manifold. The statistical descriptors and the resistance network model are then used to develop relationships between the maldistribution coefficients and the hydraulic resistances of the double manifold, the overall pressure drop and the pumping power requirements for different parallel channel numbers. Based on these, scaling laws are proposed that maintain a constant degree of maldistribution for a scale-up factor up to 102. Double manifolds designed using these scaling laws have a constant pressure drop as the number of channels increases, whilst the power requirements increase linearly. The power requirements are inversely proportional to the phase ratio maldistribution descriptor. Recommendations for the design of double manifolds for the scale-out of two-phase systems are proposed.

DEVELOPMENT AND OPTIMIZATION OF A SINGLE-STEP CATION CHROMATOGRAPHIC WHEY PROTEIN FRACTIONATION PROCESS: EVALUATION AND COMPARISON OF SCALE-UP STRATEGIES

Abstract This manuscript presents evaluation of various strategies used for the scale-up of chromatographic purification systems. Towards that end, the manuscript provides development and optimization of a single-step whey protein concentrate (WPC) fractionation process at lab scale on a 1.0 × 19 cm column using UNOsphere S. Subsequently, scale-up of this newly developed process and conduction of trials at higher scale is also undertaken by applying various scale-up strategies. For these trials, this work categorized various scale-up factors into constant velocity (CV) and constant bed volume per hour (CBVH) scale-up methods. Scale-up trials in bigger diameter (1.5 cm and 2.5 cm) columns with height to diameter ratio (H/D) =19 and <19 were performed. The effects of changing flow velocity and H/D ratio due to the applied scale-up strategy were evaluated and compared with lab performance in terms of resolution vs. height equivalent to theoretical plate (HETP) relationship. The CBVH method was found to be an efficient method for the scale-up of the developed whey protein resolution system. Also an equation for the prediction of resolution in a scaled column on the basis of a HETP-resolution correlation is presented. It is useful for the prediction of either resolution or bed height in scaled column of WPC or similar biomolecular purification systems.

Scale-Up of Lubricant Mixing Process by Using V-Type Blender Based on Discrete Element Method.

A method for scale-up of a lubricant mixing process in a V-type blender was proposed. Magnesium stearate was used for the lubricant, and the lubricant mixing experiment was conducted using three scales of V-type blenders (1.45, 21 and 130 L) under the same fill level and Froude (Fr) number. However, the properties of lubricated mixtures and tablets could not correspond with the mixing time or the total revolution number. To find the optimum scale-up factor, discrete element method (DEM) simulations of three scales of V-type blender mixing were conducted, and the total travel distance of particles under the different scales was calculated. The properties of the lubricated mixture and tablets obtained from the scale-up experiment were well correlated with the mixing time determined by the total travel distance. It was found that a scale-up simulation based on the travel distance of particles is valid for the lubricant mixing scale-up processes.

A techno-economic assessment of gas-to-liquid and coal-to-liquid plants through the development of scale factors

Fluctuations in conventional crude oil price globally and initiatives towards the phase-out of coal-based power have initiated a focus on alternative sources of liquid fuels from natural gas and coal. Gas-to-liquid (GTL) and coal-to-liquid (CTL) processes are two liquefaction technologies that could be used. There is a limited work on either the development of scale factors to estimate capital costs or on techno-economic assessments of the plants. This study addresses this gap and focusses on western Canada, which has large deposits of coal and natural gas. The capital costs of the plants' key equipment are estimated through the development of cost scale-up factors. The production cost for 50,000 bbl/day of liquid fuels from GTL and CTL plants is estimated through modelling using a bottom-up approach. The developed scale-up factors for the GTL and CTL plants were found to be 0.70 and 0.65, respectively. For both plants, most of the benefits of economies of scale are achieved at a capacity of 20,000 bbl/day. The production costs of the GTL and CTL processes are 44.61 and 57.65 Canadian cents/liter respectively. With carbon capture and sequestration (CCS), the production cost of fuel from the CTL plant is higher than from the GTL plant.

Lipid Extraction from Tetraselmis sp. Microalgae for Biodiesel Production Using Hexane-based Solvent Mixtures

Lipid extraction is a critical step in the downstream processing of biodiesel production from microalgae. Solvent extraction using mixtures of non-polar and polar solvents is one of the most well-known processes for this purpose. Hexane is the most common solvent of choice for large-scale lipid extractions due to its technical and economic advantages, especially its high selectivity toward lipids and low cost. In this study, extractions using mixtures of hexane and polar solvents were evaluated for their performance in order to develop a more efficient method for large-scale lipid extraction from microalgae. The combination of hexane and methanol resulted in the highest fatty acid methyl ester (FAME) yield for lipids from Tetraselmis sp. The effects of extraction conditions, including proportions of methanol to hexane, ratios of total solvent volume to dry biomass, and extraction time, on extraction yields were evaluated to determine optimum conditions providing higher lipid and FAME yields. The optimal conditions were as follows: proportion of hexane to methanol of 1:1, ratio of total solvent volume to dry biomass of 10 mL/g, and extraction time of 120 min. Finally, the selected solvent mixture and optimal conditions were applied to larger scale extraction experiments with scale-up factors of 10, 50, and 100. FAME yields of large-scale extractions were almost completely consistent with increasing scale-up factors. The results of this study suggest that a hexane and methanol mixture is a promising solvent for large-scale lipid extraction from microalgae.

A synthetic biological secondary metabolite, Lycogen™, produced and extracted from Rhodobacter sphaeroides WL-APD911 in an optimizatioal scale-up strategy

The optimization of fermentation medium is important for synthetic biological secondary metabolite productions. The effect of rotation speed, inoculum amount, and medium supplements on the cell growth and Lycogen™ secretion of photobacterium Rhodobacter sphaeroides WL-APD911 was evaluated. The results reveal that a higher rotational speed exhibit a higher cell density, and the increasing in the amount of inoculum amount show a slight augment on the growth of R. sphaeroides WL-APD911.In the case of nitrogen sources adding, Lycogen™ production was achieved with a 0.5mM l-lysine supplementation. Moreover, the attention of Tween 80 presented a tremendous increase in the secondary metabolite. Response surface methodology (RSM) exhibited the optimization of medium supplements for Lycogen™ invention is accomplished at molasses concentration of 10g/L, yeast extract concentration of 40g/L, 0.3% Tween 80 and NaCl concentration of 5g/L, respectively. Further, the batch fermentation is carried out in both 5L and 20L fermentors to study the scale-up process factors to be adopted. At a 20L fermentor, Lycogen™ yields under the optimal culture condition are over 2 times than in the shake flask. The present results provide the Lycogen™ optimal culture mediums, scale-up procedures and efficient extractions from R. sphaeroides WL-APD911.

Investigation on the effect of nonlinear processes on similarity law in high-pressure argon discharges

In this paper, the effect of nonlinear processes (such as three-body collisions and stepwise ionizations) on the similarity law in high-pressure argon discharges has been studied by the use of the Kinetic Global Model framework. In the discharge model, the ground state argon atoms (Ar), electrons (e), atom ions (Ar+), molecular ions (Ar2+), and fourteen argon excited levels Ar*(4s and 4p) are considered. The steady-state electron and ion densities are obtained with nonlinear processes included and excluded in the designed models, respectively. It is found that in similar gas gaps, keeping the product of gas pressure and linear dimension unchanged, with the nonlinear processes included, the normalized density relations deviate from the similarity relations gradually as the scale-up factor decreases. Without the nonlinear processes, the parameter relations are in good agreement with the similarity law predictions. Furthermore, the pressure and the dimension effects are also investigated separately with and without the nonlinear processes. It is shown that the gas pressure effect on the results is less obvious than the dimension effect. Without the nonlinear processes, the pressure and the dimension effects could be estimated from one to the other based on the similarity relations.

Sensitivity analysis of Austin's scale-up model for tumbling ball mills – Part 3. A global study using the Monte Carlo paradigm

The scale-up of batch grinding data is an attractive option for the modelling of industrial milling circuits. However, little is known in terms of the expected uncertainty attached to the predictions. This paper attempts to estimate this.For simulation purposes, coarse and fine feeds were considered in the context of an open ball milling circuit and for three predefined feed flow-rates. Realistic fluctuations were allocated to the 25 input parameters making up the simulation model. The Monte Carlo approach was then used to simultaneously process the randomly generated input parameter values. Finally, average values and standard deviations on the 50% and 80% passing sizes of the mill product were calculated in order to obtain estimates of prediction uncertainties.Global errors on the predicted full-scale mill product size were found to be as high as 70%. However, with appropriate assumptions on the scale-up correction factors, they were reduced to approximately 40%. It was also demonstrated that well planned batch tests and accurately determined batch data can further drop the error to as low as 20%. Finally, the scale-up model was found to work well when finer feeds were considered for milling at high flow-rates.