Fluidized-bed Equipment Research Articles

Development and physicochemical characterization of an antifungal cream containing dried extract of Endopleura uchi and Brazil nut oil

Endopleura uchi is a plant native to the Amazon and its chemical and pharmacological potential has been widely studied. Bertholletia excelsa oilseeds (Brazil nut) are a global highlight, with diverse applications in the cosmetic and pharmaceutical industries. Therefore, this work provided premises to assist in the development of cream formulations with dried extract from stem bark of Endopleura uchi and Bertholletia excelsa oil with the ability to inhibit strains of Candida spp. For this, the extract was prepared for 5 minutes in decoction using 10% (w/v). Drying was carried out using fluidized bed equipment. In the development of the formulations, previous physical stability after 24 hours and 30 days was used for evaluation, in addition to biological activity as an antifungal agent. After physicochemical characterization, antioxidant activity was found for dried extract of Endopleura uchi in the ABTS assay with 99.70 ± 0.00% inhibition, and DPPH with 86.30 ± 0.50%. With phytochemical investigation, it was proven that bergenin is the chemical marker for this plant. After this, it was possible to develop cream formulations using different concentrations of the extract and oil. Analyzing stability, F2 cream was selected and evaluated for 4 weeks, maintaining its original macroscopic characteristics. In antifungal activity, the MIC for the dried extract was of the 25 µg/mL for Candida albicans, Candida Krusei and Candida parapsilosis. The same good result occurred for F2 cream with more efficiently in inhibiting Candida non-albicans. The Bertholletia excelsa oil did not harm the antifungal activity.

Scaling a Gas Phase Residual Lithium Conversion Process on Ni-Rich NMC Cathode Materials in Commercial Fluidized Bed Reactors

‘Residual lithium’, the LiOH and Li2CO3 surface contamination that is ubiquitous to Ni-rich NMC manufacturing, is a significant obstacle in the large-scale production and handling of high-nickel layered oxides. These hydroxide and carbonate surface phases influence reproducibility and shelf stability of the NMC powder and cause gelation and particle aggregation during electrode casting. There is ample evidence in the literature that atomic layer deposition (ALD) possesses a two-fold solution to this problem.1-3 First, reactive organometallic species such as trimethylaluminum (TMA) can convert insulating residual lithium to a Li-rich LixAlyO conducting layer. Customizable ALD layers can then be added to inhibit the re-formation of the carbonate layer and to deter negative side reactions of the CAM surface with the liquid electrolyte. While highly impactful, these studies have mostly been relegated to small, lab-scale demonstrations of <50 g. As such, there remains a need to enable this ALD-assisted-technology for high-throughput commercial applications.In this talk, we will explore the progression of a residual lithium conversion process from lab (10 – 1000 mL) to industrial-scale (10 L – 100 L) fluidized bed equipment and how scale and material-dependent parameters can impact performance. Using a commercial NMC 811 cathode as a case study, we first applied aluminum phosphate ALD coatings on a lab-scale fluidized bed reactor to examine the interfacial and electrochemical changes of the CAM material under various process conditions. ICP-OES measurements confirmed linear and reproducible deposition versus ALD cycle number between 200- 300°C. XPS analysis showed the ALD coated NMC 811 powder had an 80% reduction in Li2CO3 versus the pristine material and that a reduction persisted even after 10 days of storage in atmospheric conditions. At standard (0.5C/1C) cycling to 4.4V, AlPO4 coatings increased cycle life by 44% versus the uncoated powder. Under optimized conditions, the process was scaled first to 1 kg and finally to 10 kg in a pilot-scale reactor. In-situ mass spectrometry indicated that residual lithium conversion byproducts such as CO2 could be used to monitor reaction progress and optimize chemical usage efficiency. Fluidization aids including vibration and mechanical stirring were used to inhibit and break up powder agglomerates. ICP-OES and electrochemical cycling data confirmed reproducible deposition and cycle life benefits versus the small scale runs and pristine materials, demonstrating a pathway for these ALD-enhanced materials to transition from lab-scale demonstration to viable product. We will discuss strategies for continuing the scaling process to 100 kg batches for commercial applications.[1] M. Young et al., The Journal of Physical Chemistry C 2019 123 (39), 23783-23790[2] P. Darapaneni et al., ACS Applied Energy Materials 2022, 5, 8, 9870–9876[3] J. Li et al., Coatings 2022, 12(1), 84

The Effect of Design and Size of the Fluid-Bed Equipment on the Particle Size-Dependent Trend of Particle Coating Thickness and Drug Prolonged-Release Profile

The focus of the current work is to study and demonstrate the impact of the design, the scale, and settings of fluid-bed coating equipment on the differences in pellet coating thickness, which in case of prolonged-release pellets dictates the drug release. In the first set of coating experiments, the pellet cores were coated with the Tartrazine dye with the aim of estimating the coating equipment performance in terms of coating thickness distribution, assessed through color hue. In the second set, drug-layered pellets were film-coated with prolonged-release coating and dissolution profile tests were performed to estimate the thickness and uniformity of the coating thickness among differently sized pellets. In both study parts, film coating was performed at the laboratory and the pilot scale and essentially two types of distribution plate and different height adjustments of the draft tube were compared. The dye coating study proved to be extremely useful, as the results enable process correction and the optimal use of the process equipment in combination with the appropriate process parameters. Preferential film coating of larger drug-containing pellets was confirmed on the laboratory scale, while on the pilot scale, it was possible to achieve preferential coating of smaller pellets using rational alternatives of settings, which is desirable in terms of particle size-independent drug release profile of such prolonged-release dosage forms.

Evaluation of powder-layering vs. spray-coating techniques in the manufacturing of a swellable/erodible pulsatile delivery system

A swellable/erodible system for oral time-dependent release, demonstrated to provide consistent pulsatile and colonic delivery performance, has been manufactured through a range of coating techniques to achieve the functional hydroxypropyl methylcellulose (HPMC) layer. Although aqueous spray-coating has long been preferred, the processing times and yields still represent open issues, especially in view of the considerable amount of polymer required to give in vivo lag phases of proper duration. To make manufacturing of the delivery system more cost-efficient, different coating modes were thus evaluated, namely top and tangential spray-coating as well as powder-layering, using a fluid bed equipment. To this aim, disintegrating tablets of 5 mm in diameter, containing a tracer drug, were coated up to 50% weight gain with low-viscosity HPMC, either as a water solution or as a powder formulation. In all cases, process feasibility was assessed following setup of the operating conditions. Irrespective of the technique employed, the resulting dosage forms exhibited uniform coating layers able to defer the onset of release as a function of the amount of polymer applied. The structure and thickness of such layers differed depending on the deposition modes. With respect to top spray-, both tangential spray-coating and powder-layering were shown to remarkably ameliorate the process time, which was reduced to approximately 1/3 and 1/6, and to enhance the yield by almost 20 and 30%, respectively. Clear advantages associated with such techniques were thus highlighted, particularly with respect to powder-layering here newly proposed for application of a swellable hydrophilic cellulose derivative.

Production and Characterization of Controlled Release Urea Using Biopolymer and Geopolymer as Coating Materials.

Synthetic polymers-based controlled release urea (CRU) leaves non-biodegradable coating shells when applied in soil. Several alternative green materials are used to produce CRU, but most of these studies have issues pertaining to nitrogen release longevity, process viability, and the ease of application of the finished product. In this study, we utilized tapioca starch, modified by polyvinyl alcohol and citric acid, as coating material to produce controlled release coated urea granules in a rotary fluidized bed equipment. Response surface methodology is employed for studying the interactive effect of process parameters on urea release characteristics. Statistical analysis indicates that the fluidizing air temperature and spray rate are the most influential among all five process parameters studied. The optimum values of fluidizing air temperature (80 °C), spray rate (0.13 mL/s), atomizing pressure (3.98 bar), process time (110 min), and spray temperature (70 °C) were evaluated by multi-objective optimization while using genetic algorithms in MATLAB®. Urea coated by modified-starch was double coated by a geopolymer to enhance the controlled release characteristics that produced promising results with respect to the longevity of nitrogen release from the final product. This study provides leads for the design of a fluidized bed for the scaled-up production of CRU.

Derivation of Entropy and Exergy Transport Equations, and Application to Second Law Analysis of Sugarcane Bagasse Gasification in Bubbling Fluidized Beds

Abstract In the present work, the transport equations for mass, momentum, energy, and chemical species as given by the Euler–Euler formulation for multiphase flows are used together with the second law of thermodynamics to derive the entropy and exergy transport equations, suitable to the study of gas-particle reactive flows, such as those observed during pyrolysis, gasification, and combustion of biomass particles. The terms of the derived equations are discussed, and the exergy destruction contributions are identified. Subsequently, a kinetic model is implemented in a computational fluid dynamics (CFD) open source code for the sugarcane bagasse gasification. Then, the derived exergy destruction terms are implemented numerically through user-defined Fortran routines. Next, the second law analysis of the gasification process of sugarcane bagasse in bubbling fluidized beds is carried out. Detailed results are obtained for the local destructions of exergy along the reactor. This information is important to help improve environmental and sustainable practices and should be of interest to both designers and operators of fluidized bed equipment.

In-Line Film Coating Thickness Estimation of Minitablets in a Fluid-Bed Coating Equipment

Film coating thickness of minitablets was estimated in-line during coating in a fluid-bed equipment by means of visual imaging. An existing, commercially available image acquisition system was used for image acquisition, while dedicated image analysis and data analysis methods were developed for this purpose. The methods were first tested against simulated minitablet's images and after that examined on a laboratory-scale fluid-bed Wurster coating process. An observation window cleaning mechanism was developed for this purpose. Six batches of minitablets were coated in total, using two different dispersions, where for the second dispersion coating endpoint was determined based on the in-line measurement. Coating thickness estimates were calculated from the increasing size distributions of the minitablet's major and minor lengths, assessed from the acquired images. Information on both the minitablet's average band and average cap coating thicknesses was obtained. The in-line coating thickness estimates were compared to the coating thickness weight gain calculations and the optical microscope measurements as a reference method. Average band coating thickness estimate was found the most accurate in comparison to microscope measurements, with root mean square error of 1.30μm. The window cleaning mechanism was crucial for the accuracy of the in-line measurements as was evident from the corresponding decrease of the root mean square error (9.52μm, band coating thickness). The presented visual imaging approach exhibits accuracy of at least 2μm and is not susceptible to coating formulation or color variations. It presents a promising alternative to other existing techniques for the in-line coating thickness estimation.

Association of PLGA Microspheres to Carrier Pellets by Fluid Bed Coating: A Novel Approach towards Improving the Flowability of Microparticles.

Micro- and nanoparticles have been vastly studied due to their biopharmaceutical advantages. However, these particles generally display very weak packing and poor mechanical properties. Hereby, a new methodology is proposed to associate poorly flowing particles to macrostructures targeting the improvement of flowability and redispersibility of the particles. Cecropia glaziovii-loaded PLGA microspheres (4.59 ± 0.04 μm) were associated with carrier pellets by film coating in a top-spray fluid bed equipment. Optimal conditions were determined employing a IV-Optimal factorial design and RGB image analysis as 1% (w/v) Kollicoat® Protect as coating polymer (2:1 weight ratio of coating suspension to carrier pellets), containing 5 mg/mL microspheres (loading of 28.07 ± 1.01 mg/g). The method led to an improvement of the overall flowability. No relevant molecular interactions between PLGA microspheres and polymers were found. Microspheres detached rapidly from the surface of the pellets, without agglomeration, when exposed to hydrodynamic forces. In vitro release profiles, prior to and after fluid bed coating, showed no relevant changes in drug release rate and extent. The methodology developed is suitable for further applications when an improvement on the flow properties and redispersibility of the product is desired. We showed an easy-to-implement methodology that can be executed without significant increase in costs.

Study on the Basic Performance of Three-phase Fluidized Bed Equipment for Solar Photocatalysis-Membrane Separation.

In this study, three-phase fluidized bed equipment for the solar photocatalysis-membrane separation (E-SPME), comprising solar photocatalytic degradation and membrane separation zones, was first introduced, and the photocatalytic degradation of acid red B wastewater (ARBW) with a TiO2 photocatalyst was investigated using the E-SPME. The experimental results indicated the circulating flow of wastewater between the two zones and the increase in the ARBW photocatalytic degradation efficiency with decreasing membrane flux. The same experimental phenomenon was observed with the change in the aeration rate in the lower water tank from 0.10 to 0.40m3 h-1 , but the degradation efficiency started to decrease with further increase in the aeration rate to 0.50m3 h-1 . The degradation efficiency on a clear day was greater than that on a cloudy day; however, it was significantly improved with the opened UV lamps on a cloudy day. The steady operation of the E-SPME was still possible by the opening of the UV lamps on completely cloudy and clear days with a solar light intensity of <13.0Wm-2 .

Numerical study of gas–solid drag models in a bubbling fluidized bed

ABSTRACTBubbling fluidized beds find application mainly in power conversion industries. For design, dimensioning, and operation of fluidized bed equipment, the understanding of multiphase gas–solid flows is of great importance. The use of computational fluid dynamics in the simulation of gas–solid systems is limited by the complexity of mathematical models, which rely on a series of empirical or theoretical correlations. In the present work, the code Multiphase Flow with Interphase eXchanges (MFIX) was employed to simulate flows in a bubbling fluidized bed and to compare results predicted using different gas–solid drag models. A two-fluid model with kinetic theory of granular flows (TFM-KTGF) was employed, in which gas–solid drag correlations, such as Gidaspow, Hill-Koch-Ladd, or Syamlal and O’Brien, were applied to model momentum transfer between phases. The results predicted were compared with each other and with experimental results from the literature. It was found that the results predicted using each model differ much. The Gidaspow and Hill-Koch-Ladd models yielded bubbles with shapes more similar to the experiments.

Improvement of mechanical properties of pellet containing tablets by thermal treatment

Batches of partially spray-dried lactose tablets with three different initial tensile strength (∼20N, ∼35N, ∼50N) were made. Changes along a 24h long thermal treatment at 100°C in tensile strength, friability, individual mass, water content, disintegration time, average free volume and wetting properties were evaluated. Caffeine containing gastroresistant pellets were gained by drug layering and filmcoating of inert microcrystalline cellulose pellet cores in fluid bed equipment. Shape, size, mechanical properties, drug content and dissolution profile of the coated pellets were determined. Batches of pellet containing tablets with three different pellet-filler ratios were compressed where partially spray-dried lactose was used as a filler-binder material.Characteristics of pellet containing tablets were evaluated before and after a 24h long thermal treatment at 100°C. Results shown that the poor initial mechanical properties (friability, tensile strength) were improved by thermal exposure while there were no remarkable alterations in drug release profiles.

Modern evaluation of liquisolid systems with varying amounts of liquid phase prepared using two different methods.

Liquisolid systems are an innovative dosage form used for enhancing dissolution rate and improving in vivo bioavailability of poorly soluble drugs. These formulations require specific evaluation methods for their quality assurance (e.g., evaluation of angle of slide, contact angle, or water absorption ratio). The presented study is focused on the preparation, modern in vitro testing, and evaluation of differences of liquisolid systems containing varying amounts of a drug in liquid state (polyethylene glycol 400 solution of rosuvastatin) in relation to an aluminometasilicate carrier (Neusilin US2). Liquisolid powders used for the formulation of final tablets were prepared using two different methods: simple blending and spraying of drug solution onto a carrier in fluid bed equipment. The obtained results imply that the amount of liquid phase in relation to carrier material had an effect on the hardness, friability, and disintegration of tablets, as well as their height. The use of spraying technique enhanced flow properties of the prepared mixtures, increased hardness values, decreased friability, and improved homogeneity of the final dosage form.

Strong Branding for World Recognition

Abstract This article elaborates how ASME Boiler and Pressure Vessel Code has played an integral role in supporting the success of Foster Wheelers’ business in the past 87 years. Foster Wheeler Power Machinery Co. Ltd. (FWPMCL) was established in China over 20 years ago and is today Foster Wheeler’s largest manufacturing facility. FWPMCL possesses an impressive résumé, supplying high-quality boiler pressure part components for the entire range of Foster Wheeler designs such as super- and subcritical pulverized coal and circulating fluidized bed equipment, heat recovery steam generators, and waste heat and solar boilers to customers around the world. All Foster Wheeler manufacturing facilities are proud holders of ASME Certificates of Authorization. FWPMCL in China holds both ‘S’ and ‘PP’ stamps. The Code has supported Foster Wheeler in maintaining the integrity of its brand and reputation for consistently delivering high-quality products globally at a competitive price.

Effect of operational conditions on the properties of pectin powder agglomerated in pulsed fluid bed

Abstract The agglomeration process enlarges particles and decreases the quantity of fine particles, leading to benefits such as lower rates of particle elutriation and reduced risks related to particle handling and inhalation. The pulsed fluid bed has some advantages over the conventional fluid bed equipment, including the improvement on fluidization of irregular particles of different sizes. The aim of this work was to study the agglomeration of pectin in pulsed fluidized bed and evaluate the physical properties of the agglomerated powder in relation to those of the raw material. The following variables were assessed: fluidizing air temperature, binder flow rate, fluidizing air velocity, and air pulsation frequency. Yields higher than 80% were achieved. There was an increase of almost 340% in the mean particle diameter. Compared with the raw material, which is more compact and circular, the agglomerated powder was more porous and irregular, and it presented improved appearance, flowability, wettability, and dissolution. The stress at fracture and the modulus of elasticity of the gel formed from the agglomerated product were higher compared with the gel obtained from the raw material showing enhanced properties as gelling and thickening agent.

Preparation and Characterization of Imidacloprid Lignin–Polyethylene Glycol Matrices Coated with Ethylcellulose

Imidacloprid, a systemic insecticide that has a water solubility of 610 mg L(-1), has been formulated in lignin-polyethylene glycol matrices by a melting process. This formulation was coated in a Wurster type fluidized-bed equipment using ethylcellulose and dibutyl sebacate. Imidacloprid has been entrapped, with an entrapment efficiency higher than 87% in all cases. Thermogravimetric analysis, differential scanning calorimetry, and Fourier transformed infrared spectroscopy studies indicate the stability and compatibility of polymers and imidacloprid. Scanning electron microscopy images show a homogeneous film of ethylcellulose in coated formulations. From T(50) values (the time taken for 50% of the active ingredient to be released into water), the release rate of imidacloprid is controlled by changing the thickness of the coating film and modifying its surface properties by adding a plasticizer. T(50) values, ranging from 3.02 to 168.6 h, allow supplying the appropriate amount of imidacloprid in each specific agronomic practice to increase the efficiency of this bioactive material and minimize the risk of environmental pollution.

Comprehensive Simulator Applied to Fluidized Bed Coal Gasification

A comprehensive simulator of fluidized bed equipment (CSFMB) has been able to reproduce experimental tests of bituminous coal gasification. The tests employed a bubbling fluidized bed pilot operating at atmospheric pressure and mixtures of air and steam were injected as gasification agents. Relatively low deviations between experimental and simulation results have been achieved. The simulator can now be applied on optimized scaling up of that equipment operating at any pressure. It also opens the possibility of integrating CSFMB as a module of wider simulations aiming optimizations of CIG/GT (Coal Integrated Gasification/Gas Turbine process) and Fisher-Tropsch.

Ethylcellulose and lignin as bearer polymers in controlled release formulations of chloridazon

Polymeric materials like ethylcellulose and lignin have been used to improve the application of the herbicide chloridazon, preparing controlled release formulations (CRFs). The lignin-based formulations prepared were coated in a Wurster-type fluidized-bed equipment using ethylcellulose and dibutylsebacate. Chloridazon has been successfully trapped, with values of encapsulation efficiency (EE) higher than 94% in all cases. FT-IR and DSC studies indicate the compatibility between polymers and chloridazon in lignin based CRFs. SEM pictures show a homogeneous film in ethylcellulose coated CRFs. Using experimental equations, the time taken for 50% of the active ingredient to be released into water ( T 50) was calculated. From the analysis of the T 50 values, it can be deduced that the release rate of chloridazon can be mainly controlled either by selecting the granule size of controlled release lignin matrixes, or by changing the thickness of the coating film and modifying its surface properties adding a plasticizer for ethylcellulose coated CRFs.

Microencapsulation of Fish Oil by Spray Granulation and Fluid Bed Film Coating

The stability of microencapsulated fish oil prepared with 2 production processes, spray granulation (SG) and SG followed by film coating (SG-FC) using a fluid bed equipment, was investigated. In the 1st process, 3 types of fish oil used were based on the ratios of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (10/50, 33/22, and 18/12). Each type was emulsified with soluble soybean polysaccharide (SSPS) and maltodextrin to produce 25% oil powders. In the 2nd process, 15% film coating of hydroxypropyl betacyclodextrin (HPBCD) was applied to the granules from the 1st process. The powder stability against oxidation was examined by measurement of peroxide values (PV) and headspace propanal after storage at room temperature and at 3 to 4 degrees C for 6 wk. Uncoated powder containing the lowest concentration of PUFA (18/12) was found to be stable during storage at room temperature with maximum PV of 3.98 +/- 0.001 meq/kg oil. The PV increased sharply for uncoated powder with higher concentration of omega-3 (in 33/22 and 10/50 fish oils) after 3 wk storage. The PVs were in agreement with the concentration of propanal, and these 2 parameters remained constant for most of the uncoated powders stored at low temperature. Unexpectedly, the outcomes showed that the coated powders had lower stability than uncoated powders as indicated by higher initial PVs; more hydroperoxides were detected as well as increasing propanal concentration. The investigation suggests that the film-coating by HPBCD ineffectively protected fish oil as the coating process might have induced further oxidation; however, SG is a good method for producing fish oil powder and to protect it from oxidation because of the "onion skin" structure of granules produced in this process.

Selección de un sistema de atomización para la formación de micropartículas de Eudragit® S100 en lecho fluido

La elaboración de micropartículas en lecho fluido es de gran interés en la industria farmacéutica, alimentaria y agrícola, ya que este tipo de formulación permite controlar la liberación de ingredientes activos y su estabilidad y funcionalidad mediante la formación de pequeñas partículas sólidas. El lecho fluido es el equipo comúnmente usado en la industria para realizar el proceso y éste puede tener dos sistemas de atomización: superior (Top spray) e inferior (Bottom spray). En este trabajo se evaluaron los dos sistemas de atomización con miras a la formación de micropartículas de Eudragit® S100.Se realizaron experimentos para ajustar los factores críticos del proceso y los niveles de éstos utilizando un diseño factorial multinivel y trabajando en un lecho fluido marca Glatt GmbH D – 01277. Los factores evaluados fueron la temperatura de entrada, la presión interna de la cámara y la velocidad de flujo. El material de recubrimiento consistió en un polímero del ácido metacrílico denominado Eudragit® S100 y como núcleo se empleó talco malla 325. El sistema seleccionado para la microencapsulación fue el de atomización superior (Top spray). Las condiciones de atomización establecidas fueron velocidad de flujo de 4,12 mL/min (flujo 8 rpm), temperatura de entrada de80ºC y presión interna de la cámara de 1 y 3 bares. Las micropartículas presentaron formas y tamaños homogéneos, menores de 100 μm.Las condiciones fijadas para el sistema de atomizaciónsuperior se pueden aplicar al desarrollo de procesos de microencapsulación de diferentes principios activos utilizando como polímero Eudragit® S100.

Optimization of fluid bed formulations of metoprolol granules and tablets using an experimental design

Background: The granulation process of a metoprolol tartrate (very difficult to process active pharmaceutical ingredient) formulation in laboratory scale fluid bed equipment was studied. Aim: To study the influence of two formulation factors and three process parameters on the characteristics of the granules and subsequently of the tablets, in the case of fluid bed granulating of a powder mix containing metoprolol tartrate. Method: In order to study the influence of formulation factors (binder solution concentration and the silicon dioxide ratio) and process factors (atomizing pressure, the length of the final drying phase, and the inlet air temperature) on the technological and pharmaceutical properties of granules and tablets, a fractional factorial experimental design resolution V+ with five factors and two levels was used. Results: A high atomizing pressure allows us to obtain fine granules with large poly-dispersion index and granules with high tapped and untapped density, tablets with short disintegration time, short mean dissolution time, and a high percentage metoprolol tartrate release in the first 15 minutes. A lower concentration of binder solution allows us to obtain granules with very good flow properties, tablets which have no tendency to stick on the set punch of tabletting machine and no capping. The final drying time of granules has an influence only on the granule's relative humidity and tapped and untapped density, without any influence on the granules flow properties. Conclusions: The practical experimental results from the formulation processed in optimal working conditions were close to the predicted ones by Modde 6.0 software.