Focused Beam Reflectance Measurement Probe Research Articles

Investigation of the homogeneity of particle suspension

The homogeneity of particle suspension has attracted more attention in the fields of rehydrating milk beverages. This work focus on size characterization of the floating, sticking (on the wall), suspended and settling particles involving both online and offline sizing techniques. Focused Beam Reflectance Measurement (FBRM) is a powerful online technique that is capable for measuring and analysing chord length distribution (CLD) of the suspended particles in liquid. It has been widely used in terms of monitoring size evolution of crystallization and sedimentation processes. In this work, a new approach that involves FBRM probe to measure the particle size distribution has been developed. The probe is placed at three different height levels in a standard container after one hour of free sedimentation. The results suggest that the finest fraction is dominant at all three heights but the percentage of it decreases with an increase of larger particles when looking at the bottom. Besides, all the floating, sticking and settling particles are collected and analysed, and the particle size distributions (PSDs) are obtained and compared using the offline sizing techniques, such as optical microscope and Camsizer. In the results, the suspended particle is the smallest one followed by the sticking and the floating particles, while the settling particle is the largest. However, for the sticking particles sticking on the wall, a great number of agglomerates is found during the test due to adhesion force, indicating that the size distribution might be overestimated. Based on the results, the target particle size range that can be stably suspended in the model suspension was selected by eliminating the unfavourable fractions.

Real-time particle size analysis using focused beam reflectance measurement as a process analytical technology tool for continuous microencapsulation process

The online real-time particle size analysis of the microencapsules manufacturing process using the continuous solvent evaporation method was performed using focused beam reflectance measurement (FBRM). In this paper, we use FBRM measurements to investigate the effects of polymer type and compare the size distributions to those obtained using other sizing methods such as optical microscope and laser diffraction. FBRM was also utilized to measure the length-weighted chord length distribution (CLD) and particle size distribution (PSD) online during particle solidification, which could not be done with laser diffraction or nested sieve analysis. The chord lengths and CLD data were taken at specific times using an online FBRM probe mounted below the microparticle. The timing of the FBRM determinations was coordinated with the selection of microparticle samples for particle size analysis by optical microscope and laser diffraction calculation as a reference. For all three produced batches tested, FBRM, laser diffraction, and sieve analysis yielded similar results. Hardening time for the transformation of emulsion droplets into solid microparticles occurred within the first 10.5, 19, 25, 30, and 55 min, according to FBRM results. The FBRM CLDs revealed that a larger particle size mean resulted in a longer CLD and a lower peak of particle number. The FBRM data revealed that the polymer type had a significant impact on microparticle CLD and the transformation process.

PAT solutions to monitor adsorption of Tetanus Toxoid with aluminum adjuvants

The focus of this study was to examine the small-scale adsorption process of Tetanus Toxoid (TT) as a model protein antigen to aluminum phosphate (AlPO4) and aluminum oxyhydroxide (AlOOH) adjuvants with real-time monitoring by in-line ReactIR™, ParticleTrack™ based on Focused Beam Reflectance Measurement (FBRM) and EasyViewer™ probes. The adsorption process of AlPO4 and AlOOH with TT using was monitored in the small-scale reactors. Conformational changes in TT were monitored using in-line infrared probe ReactIR, whereas particle formation associated with protein adsorption were measured by particle size, count, and imaging tools, such as ParticleTrack with FBRM and EasyViewer probes. ParticleTrack distribution results and kinetic measurements were also supported by observations made using EasyViewer. In addition to EasyMax, BioBLU reactor was also used for the adsorption experiments. ReactIR with ATR-Fiber probe was effectively able to monitor adsorption progress of TT to AlOOH and to AlPO4. ReactIR, EasyViewer, and ParticleTrack provided detailed mechanistic and kinetic information for reaction of TT with AlPO4 and AlOOH. These in-situ measurements revealed a possible multi-step process for TT to AlPO4 which may be an indication of antigen adsorption.

Effect of Different Shear Rates on Particle Microstructure of Cementitious Materials in a Wide Gap Vane-in-cup Rheometer.

Rheological properties of cementitious suspensions are affected not only by their mixture composition but also by process-related factors such as shear history. To enable a model-based description, investigations were carried out on the effect of shear history (shear rate variation over time) on the cement paste agglomeration state. Therefore, a Focused Beam Reflectance Measurement (FBRM) system and a wide gap rheometer were coupled to study the relation between shear history and in-situ chord length distribution simultaneously, indicating particle agglomeration. Hence, the effect of average shear rates (resulting from the applied shear profile), as well as shear rate distribution within the gap (local shear rates) on the particle agglomeration state have been investigated. The rheological properties of cement paste were evaluated with the Reiner–Riwlin approach. Furthermore, the agglomeration state of the particles was compared for different average shear rates and local shear rates at various positions of the FBRM probe. The results show that the median chord length increases in all positions when the average shear rate is decreased, indicating increasing particle agglomeration. Moreover, due to variable local shear rates at different FBRM probe positions, different agglomeration states are observed, resulting from two factors, shear rate dependent particle agglomeration and shear-induced particle migration.

Investigation of rehydration of food powder mixtures

This study focuses on the rehydration of an amorphous powder (maltodextrin DE19) and a crystalline powder (lactose 100 M) and mixtures of these powders. The rehydration process was tracked using a Focused Beam Reflectance Measurement (FBRM) probe and a video camera. The setup allows for real-time monitoring of all rehydration steps.The dispersion behaviour of the mixtures, especially mixtures with between 40 and 60% lactose content differs from behaviour of both pure powders at an agitation rate of 600 rpm. Surprisingly, the sinking times of the powder mixtures were observed to be higher than the sinking times of component powders at higher temperatures. Increasing temperature and agitation rate improved powder wetting and rehydration.A mechanism for increased sinking time of powder mixes was proposed. Finally, regime maps were constructed to summarize the effect of mix composition, temperature and agitation rate on rehydration behaviour. This mapping approach can be used to qualitatively assess rehydration.

Hydrate phase equilibrium condition of the synthetic natural gas with high content of CO2 in the electrolyte solutions containing methanol

It is well known that CO2 is easier to form hydrate because its hydrate phase equilibrium pressure was lower than CH4 at a given temperature. The natural gas containing high content of CO2 increases pipeline blockage risk due to hydrate problem in realistic situations. In industry, the organic inhibitors are often added to pipelines combined with the dissolved salts in the produced water to prevent hydrate formation. In this study, the hydrate phase equilibrium condition of two synthetic natural gas (SNG) samples (with high and low content of CO2) in various systems was measured with the isothermal pressure search method. It was found the adding of 0.1 mass fraction MeOH and 0.075 mass fraction NaCl to pure water lowered the hydrate equilibrium temperature of SNG with high content of CO2 7.61 K at a given pressure. In addition, the hydrate morphology and size was investigated with the particle video microscope and focused beam reflectance measurement probes, respectively. The SNG formed flake-like hydrates in the pure water and salt solution systems, respectively, while powder-like hydrates occurred in the system containing MeOH. It was found that the average chord length of SNG hydrate changes from 205 μm to 53 μm after adding MeOH in the system. Based on the measured phase equilibrium data, the hydrate dissociation enthalpy was calculated with the Clausius-Clapeyron equation. The results indicated that the hydrate dissociation enthalpies of two SNG samples are (67.32 and 63.04) kJ·mol−1, respectively. The inhibitors (salt and MeOH) have no effect on the hydrate dissociation enthalpy since they would not enter hydrate cavity.

Continuously monitored lactose crystallization in a vibrated bed

Abstract The aim of this work was to evaluate the crystal size distribution (CSD) and microscopy of the crystalline phase in isothermal lactose crystallization, using a high seeding concentration (dense phase). In-line monitoring was carried out using Focused Beam Reflectance Measurement (FBRM) and Particle Vision Measurement (PVM) probes in a stainless steel trunk-conical shaped jacketed crystallizer. The vibratory shaking system consisted of two perforated discs coupled to a movable axle. A conventional crystallization unit, with a three-blade propeller attached to a stainless steel shaft, was used for comparison. Concentrated cheese whey, purified with an organic coagulant, and commercial lactose solutions were used. Crystallization was improved in the high-purity solutions. Microparticles and/or aggregates appeared before seeding, mainly in the purified cheese whey solution, in which there are impurities. Secondary nucleation was present in both the vibratory agitation and conventional rotary agitation systems, being intensified by increases in agitation. Crystallization in a vibratory system should be carried out with a vibration frequency of 250 rpm, since an increase to 400 rpm reduced the amount of larger crystals.

Evaluation of whey protein as a natural hydrate kinetic inhibitor

The toxicity of hydrate inhibitors used in the field has attracted more attention. A natural material, i.e., whey protein, was assessed to act as kinetic hydrate inhibitors (KHIs) in a sapphire cell and an autoclave equipped with particle video microscope (PVM) and focused beam reflectance measurement (FBRM) probes. The pressure dropping method was utilized to estimate the hydrate induction time, and the results demonstrate that the hydrate inhibition performance of whey protein is superior to that of the commercial KHI, polyvinylpyrrolidone. The induction time for the pure water system was found to increase linearly with the increase in the dosage of whey protein until it reached approximately 2.5 wt%. As it is usually inevasible to apply KHIs under conditions of high water contents, the feasibility of whey protein as a KHI in the (oil + water) system with and without an emulsifier of Tween 20 was evaluated. A small amount of oil was found to have no obvious influence on the induction time for the system with whey protein under the circumstances without the addition of emulsifier. When Tween 20 was added, the induction time obviously increased under the same operating conditions, which could be attributed to the emulsifier–protein interactions in aqueous solutions. The oil drops decrease and are distributed more evenly with the increasing dosage of Tween 20 under the PVM and FBRM probes measurement. Additionally, the particles decrease during the hydrate formation process. This work presents a natural KHI and gives the inhibition discipline in a high-water-content system.

Effects of Scale-Up on the Mechanism and Kinetics of Crystal Nucleation

Insight into nucleation kinetics and other nucleation parameters can be obtained from probability distributions of induction time measurements in combination with the classical nucleation theory. In this work, induction times of crystallization were recorded using a robust and automated methodology involving a focused beam reflectance measurement probe. This methodology is easily interchangeable between different crystallizers which allowed us to investigate the effects of scale-up on the kinetics of crystal nucleation of paracetamol from 2-propanol in four different crystallizers, ranging from small magnetically stirred 10 mL solutions to overhead-stirred solutions of 680 mL. The nucleation rate was an order of magnitude faster in the magnetically stirred crystallizer as compared to the crystallizers involving overhead stirring. The thermodynamic part of the nucleation rate expression did not significantly change the nucleation rate, whereas the kinetic nucleation parameter was found to be the rate-determining process when the crystallization process was scaled-up. In particular, the shear rate was rationalized to be the part of the kinetic parameter that changes most significantly when the crystallization process was scaled-up. The effect of shear rate on the nucleation kinetics decreases with increasing volume and plateaus when the volume becomes too large. In this work, the nucleation mechanism was also investigated using the chiral sodium chlorate system. These experiments showed that the single nucleus mechanism is the underlying nucleation mechanism in all four tested crystallization setups when supersaturation remains the same. When the supersaturation was changed continuously through cooling, crystallization was driven by a multinucleus mechanism. The automated and robust method used to measure induction times can easily be extended to other crystallizers, enabling the measurement of induction times beyond small crystallizer volumes.

Investigation on natural gas hydrate dissociation from a slurry to a water-in-oil emulsion in a high-pressure flow loop

Investigations of natural gas hydrate dissociation from a slurry to a water-in-oil emulsion are conducted in a high-pressure hydrate experimental flow loop equipped with on-line microcosmic instruments including a focused beam reflectance measurement (FBRM) probe and a particle video microscope (PVM) probe. Three stages of the dissociation processes are observed and sketched in a conceptual mechanistic diagram, including initial dissociation with agglomeration, dissociation with breakage and re-aggregation, and thorough dissociation. The influences of initial pressure, flow rate, and water cut on hydrate dissociation are discussed. The pressure drop is increased by hydrate particle agglomeration, which increases the risk of hydrate plugging; thus, hydrate systems require close monitoring during the hydrate slurry dissociation process. Based on the classical kinetics theory, an improved hydrate dissociation model is developed by introducing a coupled heat- and mass-transfer influence coefficient and by considering the changes in the hydrate dissociated area based on the chord length data recorded by the FBRM probe. The intrinsic rate constant for natural gas hydrate dissociation is within the range of 1.41 × 103–7.18 × 104mol·Pa−1·s−1·m−2, and the activation energy of dissociation ranges from 68.2 to 72.3 kJ·mol−1. The reported investigation is significant for the application of hydrate slurries in risk-management methods to address issues of hydrate flow assurance in deep-water systems.

On-line observation of the crystal growth in the case of the non-typical spherical crystallization methods of ambroxol hydrochloride

Spherical crystallization can be an important technological step in the production of a solid form active agent. By the production of spherical crystals, direct compression tablet making can be applied to the powder material. This method makes the tableting process quicker, shorter and more economical with reduced amounts of additives and a reduced number of technological steps. This way, the granulation method can be avoided, which is also advantageous for a moisture sensitive drug.In this paper, we presented Focused Beam Reflectance Measurement (FBRM) studies applied in the case of the non-typical spherical crystallization methods of the active pharmaceutical ingredient ambroxol hydrochloride. Spherical agglomeration and controlled cooling crystallization methods were carried out based on our previous studies regarding these methods and the crystal formation processes were investigated with FBRM probe. Critical agglomeration periods and other mechanisms, such as the breakage of the agglomerates and the precipitation of small particles, were investigated. Chord length values were observed continuously and samples were taken out in certain points of the crystallization. Particle size analysis was carried out in each case to obtain information on the particle size enlargement caused by the crystallization methods. With the application of light microscopic analysis, aspect ratio and roundness values were also determined to obtain pieces of information on the sphericity-changes of the particles throughout the crystallization and large improvements were presented either for these parameters (aspect ratio from ~ 1.7 to ~ 1.3; roundness from ~ 2.4 to ~ 1.5) and the mean particle size (from ~13 μm to 120–400 μm). Among others, it was revealed that after the spherical agglomeration method (SA), mostly crystal agglomerates were formed, while slow cooling crystallization with alternating temperature profile (ATP) yielded larger and probably harder individual crystals.

Investigation on hydrates blockage and restart process mechanisms of CO2 hydrate slurry flow

AbstractBeing an alternative environment‐friendly fluid for the refrigeration process, CO2 hydrate slurry is undesired to result in hydrate blocking in the system. A series of water‐based CO2 hydrate slurry experiments were conducted to investigate hydrate blockages in a high‐pressure flow loop. Blocking would occur soon after CO2 hydrate formation onset. Rapid restart process after the first blocking was found to have serious consequence by inducing a fast hydrate regrowth and an irreversible secondary blocking. The mechanisms of the first blocking and the secondary blocking after the restart process were proposed, based on the observed phenomena and the particle chord length distribution data recorded by focused beam reflectance measurement probe. The influences of the initial flow rate on the supercooling, the induction time, the restart time, and the required time for the secondary blocking after the restart process were analyzed. The understanding on the blocking and restart process mechanisms of CO2 hydrate slurry is important not only in the development of hydrate‐based refrigeration system but also in the field of flow assurance in the oil and gas pipeline or for other applications such as the replacement of methane by CO2 in the naturally occurring hydrate exploration.

Feasibility of Focused Beam Reflectance Measurement (FBRM) for Analysis of Pharmaceutical Suspensions in Preclinical Development.

This study examined the use of focused beam reflectance measurement (FBRM) for qualitative and quantitative analysis of pharmaceutical suspensions with particular application to toxicology supply preparations for use in preclinical studies. Aqueous suspensions of ibuprofen were used as prototype formulations. Initial experiments were conducted to examine the effects of operational conditions including FBRM probe angle, probe location, and mixing (method and rate of mixing) on the FBRM analysis. Once experimental conditions were optimized, the homogeneity and sedimentation-redispersion of particles in the suspensions were assessed. Ibuprofen suspension under continuous agitation was monitored using FBRM for 60h to study particle size change over time. Another study was performed to determine if particle count rates obtained by FBRM could be correlated to suspension concentration. The location and the angle of the FBRM probe relative to the beaker contents, and the rate and the method of mixing the suspension were found to be sensitive parameters during FBRM analysis. FBRM was able to monitor the process of particle sedimentation in the suspension. The attrition of ibuprofen particles was detectable by FBRM during prolonged stirring with an increase in the number of smaller particles and decrease in the number of larger particles. A strong correlation was observed between particle count rate by FBRM and ibuprofen concentration in the suspension. Also, change in content uniformity in the suspension at different locations of the beaker was represented by FBRM particle count. Overall, FBRM has potential to be a useful tool for qualitative and quantitative analysis of pharmaceutical suspensions.

Investigation of a solution‐mediated phase transformation of pranlukast DMF solvate to hemihydrate

Pranlukast is a potent selective cysteniyl leukotriene receptor antagonist to treat bronchial asthma and allergic rhinitis, which exists in several crystal forms. In this work, solution‐mediated phase transformation process from Pranlukast DMF solvate to the hemihydrate form was studied by using the focused beam reflectance measurement probe combined with powder X‐ray diffraction. The influence factors such as temperature, solvent composition, amount of added solid, and stirring rate were investigated. Results showed that higher temperature, larger mole fraction of water, lower amount of added solid, and faster stirring rate could accelerate the solution‐mediated phase transformation process.

Microscale Detection of Hydrate Blockage Onset in High-Pressure Gas–Water Systems

A high-pressure stirred autoclave cell equipped with a focused beam reflectance measurement (FBRM) probe and a particle video microscope (PVM) was used to study hydrate formation and plugging in gas–water systems as a function of shear rate. These probes allowed estimates of the mean hydrate particle size and number of hydrate particles to be correlated with the hydrate volume fraction and the hydrate slurry’s resistance-to-flow. Before reaching the hydrate volume fraction φtransition at which the hydrate slurry first exhibits a measurable increase in resistance-to-flow at ≈(16 ± 2) vol %, clear changes in the measured number and size of the hydrate particles were observed. Initially, hydrate particles within the FBRM probe’s field of view decreased in size and increased in number until a maximum was reached at concentrations of 2–9 vol % (increasing with shear rate). However, with continued hydrate growth, the number of particles within the FBRM probe’s field of view unexpectedly decreased and eventually...

Experimental study of dispersed oil-water flow in a horizontal pipe with enhanced inlet mixing, Part 2: In-situ droplet measurements

Droplet size measurements in premixed oil-water flow are presented. Three traversable focused beam reflectance measurement probes (FBRM) positioned along the test section allowed for measuring averaged droplet size profiles over the cross section. Measurements for two mixture velocities, Umix=0.5m/s and Umix=1m/s, and the complete range of input water fractions were performed with tap water and medium viscosity mineral oil. The flow facility provided a 10cm inner diameter test section of 24m total length. Flow development in terms of droplet growth was documented. Averaged droplet sizes showed to be a function of the dispersed phase fraction with sizes increasing towards a maximum at phase inversion. Different flow patterns show characteristic droplet size profiles over the cross-section. Common models over-predict the presented droplet size data, most probably as a result of enhanced inlet mixing and underdeveloped flow.

Chord length distribution to particle size distribution

A simple model is presented to extract the particle size distribution (PSD) from the chord length distribution measured using a focused beam reflectance measurement probe. The model can be implemented using simple spread sheeting tools and does not require the description of additional parameters as opposed to previous models. The model was validated for two systems consisting of spherical ceramic beads by comparing model predicted PSD against the PSD obtained through image analysis (IA). Then, the model was evaluated by considering various systems consisting of irregularly shaped particles (sand/zinc dust/plasma alumina). Model predictions accurately predicted the mean but over‐predicted the variance of the PSD in comparison with the PSD obtained from IA. However, overall, a reasonable agreement was observed. Finally, the model was shown to be accurate in predicting PSD in comparison with the measured PSD for systems of practical relevance such as for paracetamol and p‐aminophenol crystals. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4215–4228, 2016

Evaluation of Gas Hydrate Anti-agglomerant Based on Laser Measurement

The feasibility of evaluating the performance of anti-agglomerants from analyzing the variation of morphologies and chord length of particles was examined using an autoclave installed with a particle video microscope and focused beam reflectance measurement probes. The experimental results from methane + water + diesel oil systems show that the agglomeration of hydrate can be judged directly from two laser probes. With the action of an effective anti-agglomerant, the size of droplets/hydrate particles is uniform and tends to that before hydrate formation when most water converts to hydrate or the system stops stirring for 9 h, although the agglomeration occurs when water droplets initially convert into hydrates. The evaluation method was examined under different anti-agglomerant concentrations, water cuts, and subcoolings for water + diesel oil systems. The action mechanism of anti-agglomerants was also proposed.

Insights into methane hydrate formation, agglomeration, and dissociation in water + diesel oil dispersed system

Methane hydrate formation and dissociation in (5vol% water+95vol% diesel oil) dispersed system containing a combined anti-agglomerant were experimentally studied using a high pressure autoclave installed with particle video microscope and focused beam reflectance measurement probes. The agglomeration of hydrate was found to occur at the initial hydrate formation stage. With the continuous formation of hydrate, the agglomeration of hydrate will be inhibited and hydrate was dispersed with the action of the anti-agglomerant. The agglomeration of hydrate also occurs when the hydrate containing fluid is under static state for a certain time. Larger hydrate particles attached by gas bubble with grape-like shape were found during hydrate dissociation. The dissociated surface water would contact with un-dissociated hydrate and accumulate to larger water/hydrate particles may be the reason that causes the agglomeration during initial hydrate dissociation process. A mechanism was proposed to describe hydrate dissociation from water in oil dispersed system.

Memory Effect Test of Methane Hydrate in Water + Diesel Oil + Sorbitan Monolaurate Dispersed Systems

Formation and reformation of methane hydrate in (water + diesel oil + sorbitan monolaurate) dispersed systems have been investigated to test the memory effect using particle video microscope and focused beam reflectance measurement probes. The factors which would affect methane hydrate formation, the dosage of sorbitan monolaurate, water cut, and initial experimental temperature, were examined. The results show that there exists obvious memory effect when methane hydrate reformed in water/diesel oil dispersed systems at initial temperature near methane hydrate formation zone, even maintaining at the initial temperature for 168 h after methane hydrate dissociation. The subcooling will increase with prolonging of maintaining time, which suggesting that memory effect would disappear if time is long enough. When initial temperature increases to 5 K higher than the equilibrium value, the subcooling of reformation of methane hydrate is similar to that of hydrate first formation, which implying that memory effec...