Control of the morphology and the size of complex coacervate microcapsules during scale‐up

Scale‐up of complex coacervation, a fat encapsulation technology, is not trivial since the microcapsules morphology and size are highly affected by the processing conditions. So far it has been achieved empirically (trial and error approach). The goal of this study was to produce at various scale capsules with a single‐oil droplet as the core material and small enough to be below sensory threshold. The turbulence level was identified as the main scale‐up criterium and a master‐curve could be drafted showing the capsule mean diameter as function of the Reynolds number, independent of the level of production scale. From a parent emulsion with specific oil droplets size (12–15 μm), the Reynolds number had to be maintained above a critical value (15,000) to avoid capsules agglomeration with multiple oil cores and large particle sizes. To avoid aggregation, this turbulence level had to be kept until the temperature dropped below a critical value (14°C for a cooling rate of 35°C/2 h). Applying these learning led to a successful scale‐up from bench (2 L) to a pilot plant scale of 50 L. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Hydrodynamic and thermal experimentation on square‐based spouted beds for polymer upgrading and unit scale‐up

This paper presents the results from an extensive experimentation on polyester chips heating, crystallization and upgrading in three different size spouted bed units: a cylindrical 0.15 m diameter × 1.3 m tall, a 0.35 m square‐based × 2.1 m tall parallelepiped and a sextuple multi‐spouting 0.7 × 1.05 m² demonstration reactor for solid state post‐polymerization. The first apparatus was finalized to measuring several process operating variables (maximum gas temperature at the inlet, overall heat transfer coefficient and particle agglomeration tendency); the second unit provided the hydrodynamical data necessary to scale‐up the system, insert into a PET upgrading process of 30 ton/day operating capacity and partially replace a bubbling fluidized bed heating/crystallizing unit. The ultimate goal of the project consisted in intensifying the process design by saving gas compression and thermal energy. The hydrodynamical findings of the squared modular unit were compared against several existing correlations: Manurung's equations for the maximum pressure drop and the pressure drop at stable spouting required a minimal alteration; Mathur and Gishler's equation properly fitted the experimental minimum spouting velocity. The continuously operating multiple spouting apparatus showed that regulating the solids level was an issue mainly due to the very large particle throughput, if related to the mixing efficiency of each module; reciprocal interference between spouted bed cells was manifested.     

Effects of axial circulation and dispersion geometry on the scale‐up of ultrasonic extraction of polysaccharides

The ultrasonic‐assisted extraction of polysaccharides (PS) from Ganoderma lucidum, was subjected to a scale‐up study. 0.25 L extractor was used to optimize the extraction conditions toward maximum yield of PS. The extracted PS was observed to be reduced by increasing the scale from 1 to 6 L. To intensify the extraction, axial circulation at different stirring rates was induced and optimized in a 3 L U‐tube extractor. Although circulation at 300 rpm improved the yield of PS for 3 L, introducing dispersion geometry (conical funnel) and adjusting the radiation distance in a 6 L U‐tube extractor further intensified the extraction efficiency. A radiation distance of 4 cm and circulation induced using 600 rpm enhanced the PS as compared to the conventional 6 L extractor. Overall, the scale‐up from 0.25 to 6 L was successful and introducing circulation and dispersion geometry intensified the extraction efficiency under similar dissipation of ultrasonic power. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1483–1491, 2015     

A coupled population balance model and CFD approach for the simulation of mixing issues in lab‐scale and industrial bioreactors

Lab‐scale (70 L) and industrial scale (70 m³) aerated fermenters are simulated using a commercial computational fluid dynamics code. The model combines an Euler‐Euler approach for the two‐phase flow, a population balance model for biological adaptation to concentration gradients, and a kinetic model for biological reactions. Scale‐up at constant volumetric mass transfer coefficient is performed, leading to concentration gradients at the large scale. The results show that for a given concentration field and a given circulation time t_c, the population (physiological) state depends on the characteristic time of biological adaptation T_a. The population specific growth rate (T_a?t_c) is found independent of the spatial location and closely related to the volume average concentration. Oppositely, the population specific uptake rate (T_a～t_c) is spatially heterogeneous. The resulting local disequilibria between the uptake rate and the growth rate provide an explanation for the decreased performances of poorly macromixed industrial bioreactors. © 2013 American Institute of Chemical Engineers AIChE J, 60: 27–40, 2014     

Electrolytic removal of ammonia from brine wastewater: scale‐up,operation and pilot‐scale evaluation

Brine wastewater with a high ammonia content from an iodine processing plant (commonly called kansui in Japan) was treated by electrolysis. The system, which can be considered as an indirect electrolytic treatment process, generates chlorine at the anodes and initiates the formation of mixed oxidants like hypochlorous acid. The oxidants then act as agents for ammonia destruction. Laboratory‐scale experiments showed that high ammonia concentrations (as much as 200 mg dm^?3) could be completely removed within a few minutes, and could be considered a good alternative for efficient ammonia removal from saline wastewaters. From laboratory‐scale experiments in the batch and continuous modes, the charge dose was analyzed and used as the operating and scale‐up factor. The value of the charge dose was not severely affected by changes in operating conditions such as electrode spacing and temperature. The charge dose from batch and continuous runs was found to be in the range of 23 C (mg NH₄‐N removed)^?1 to 29 C (mg NH₄‐N removed)^?1. Using the charge dose obtained from laboratory‐scale continuous electrolysis experiments as the scale‐up factor, a pilot‐scale reactor was designed, and the operating conditions were calculated. In the pilot‐scale reactor tests at different flow rates, the effluent ammonia concentrations were reasonably close to the calculated values predicted from the charge dose equation. Copyright © 2004 Society of Chemical Industry     

Operating and scale‐up factors for the electrolytic removal of algae from eutrophied lakewater

Electrolytic removal of algae was conducted in batch and continuous reactors to investigate operating factors affecting removal efficiency and to explore engineering relationships which could be useful for operation and scale‐up. The system integrated both electro‐flocculation and electro‐flotation mechanisms by using polyvalent metal anodes and inert metal cathodes. Batch reactor studies confirmed that high electrical input power or higher electrical current achieved higher and faster removal efficiencies. Natural liquid circulation was observed during electrolytic operation and increased with higher electrical power. However, a small degree of external mixing may be useful at lower electrical power input. Electro‐flotation alone could not achieve complete algae removal (maximum efficiency 40–50%), and showed the importance of algal floc formation for the complete removal of algae. In continuous electrolysis experiments, the ratio of the volumetric current intensity (amperes dm^?3) and the chlorophyll a loading (mg dm^?3 h^?1) was found to be a useful operating and scale‐up factor to balance high algal removal efficiency with minimum release of excess aluminum. This ratio was eventually found to be just the charge dose or the amount of coulombs required to remove a unit mass of chlorophyll a. The optimum charge dose was determined and used to relate the operating current and electrolysis time of a continuous process. © 2002 Society of Chemical Industry     

Large‐scale sonochemical reactors for process intensification: design and experimental validation

Acoustic cavitation results in substantial enhancement in the rates of various chemical reactions but the existing knowledge about the application of reactors based on acoustic cavitation is limited to very small capacities (of the order of few millilitres). In the present work, an overview of the application of acoustic cavitation for the intensification of chemical reactions has been presented briefly, discussing the causes for the observed enhancement and highlighting some of the typical examples. A novel reactor has been developed operating at a capacity of 7 dm³ and tested with two reactions, ie liberation of iodine from aqueous potassium iodide and degradation of formic acid. The energy efficiency of the reactor has been calculated and compared with the conventional sonochemical reactors. The effect of frequency of irradiation on the percentage conversion of the reactants has been studied. Due to quite low conversions in the case of formic acid degradation, further intensification was attempted using aeration, addition of hydrogen peroxide, and the presence of solid particles (TiO₂). Compared with conventional reactors the novel reactor gives excellent results and it can be said that the future of using acoustic cavitation for process intensification lies in the development of large‐scale multiple frequency multiple transducer reactors. Copyright © 2003 Society of Chemical Industry     

Reduced‐scale test to assess the effect of fire barriers on the flaming combustion of cored composites: An upholstery‐material case study

Herein, we describe a reduced‐scale test (“Cube” test), measuring the fire performance of specimens including a fire barrier (FB) and a flammable core material, which acts as the main fuel load. The specimen is intended to reproduce a cross‐section of a composite product where heat/mass transfer occurs primarily in a direction perpendicular to the FB. The Cube test procedure and benefits are discussed in this work by adopting residential upholstery furniture as an exemplary study. One flexible polyurethane foam, one polypropylene cover fabric, and 10 commercially available FBs were selected. They were used to compare the fire performance of FBs, measured in terms of peak of heat release rate, in the ASTM E1474‐14 standard test and the newly developed Cube test. Edge effects severely affected the performance of FBs in the ASTM E1474‐14 standard test but not in the Cube test. Furthermore, appropriate test conditions were determined in the Cube test to measure the so‐called “wetting point,” that is, the time and value of heat release rate measured when flammable liquid products were first observed on the bottom of the specimen. The relevance of the “wetting point” in terms of full‐scale fire performance and failure mechanism of FBs is discussed.     

A full‐scale trickling filter for the simultaneous removal of ammonium,iron and manganese from potable water

Ammonium, iron, manganese and hydrogen sulfide are a serious problem for water reservoirs all over the world. The aim of this work was the design, construction and operation of a full‐scale trickling filter for the simultaneous removal of the above pollutants. The long‐term removal efficiency and the effect of environmental and operating conditions on filter performance were studied. Start‐up time of the filter was minimized using as inoculum backwash water from an existing pilot‐scale plant, while natural advection was adequate to provide sufficient aeration. Redox potential variation throughout the filter depth enhanced simultaneous removal of the pollutants. Under steady operating conditions the filter presented perfect performance, while under pollutant concentration and/or hydraulic loading shocks the filter retained high removal efficiency. Seasonal or daily temperature variations did not affect filter performance since raw water temperature was constant at 20 °C. The proposed system exhibited high pollutant removal rates for all hydraulic and pollutant loadings tested, under various environmental conditions. The simplicity of the installation and the minimal operating cost provide an effective solution to a serious environmental and social problem. Copyright © 2010 Society of Chemical Industry     

An Engineered Biocatalyst for the Synthesis of Glycoconjugates: Utilization of β1,3‐N‐Acetyl‐D‐glucosaminyltransferase from Streptococcus agalactiae Type Ia Expressed in Escherichia coli as a Fusion with Maltose‐Binding Protein

A fusion protein composed of β1,3‐N‐acetyl‐D ‐glucosaminyltransferase (β1,3‐GlcNAcT) from Streptococcus agalactiae type Ia and maltose‐binding protein (MBP) was produced in Escherichia coli as a soluble and highly active form. Although this fusion protein (MBP‐β1,3‐GlcNAcT) did not show any sugar‐elongation activity to some simple low‐molecular weight acceptor substrates such as galactose, Galβ(1→4)Glc (lactose), Galβ(1→4)GlcNAc (N‐acetyllactosamine), Galβ(1→4)GlcNAcβ(1→3)Galβ(1→4)Glc (lacto‐N‐tetraose), and Galβ(1→4)GlcβCer (lactosylceramide, LacCer), the multivalent glycopolymer having LacCer‐mimic branches (LacCer mimic polymer, LacCer primer) was found to be an excellent acceptor substrate for the introduction of a β‐GlcNAc residue at the O‐3 position of the non‐reducing galactose moiety by this engineered enzyme. Subsequently, the polymer having GlcNAcβ(1→3)Galβ(1→4)Glc was subjected to further enzymatic modifications by using recombinant β1,4‐D ‐galactosyltransferase (β1,4‐GalT), α2,3‐sialyltransferase (α2,3‐SiaT), α1,3‐L ‐fucosyltransferase (α1,3‐FucT), and ceramide glycanase (CGase) to afford a biologically important ganglioside; Neu5Aα(2→3)Galβ(1→4)[Fucα(1→3)]GlcNAcβ(1→3)Galβ(1→4)GlcCerα(IV3Neu5Acα,III3Fucα‐nLc4Cer) in 40% yield (4 steps). Interestingly, it was suggested that MBP‐β1,3‐GlcNAcT could also catalyze a glycosylation reaction of the LacCer mimic polymer with N‐acetyl‐D ‐galactosamine served from UDP‐GalNAc to afford a polymer carrying trisaccharide branches, GalNAcβ(1→3)Galβ(1→4)Glc. The versatility of the MBP‐β1,3‐GlcNAcT in the practical synthesis was preliminarily demonstrated by applying this fusion protein as an immobilized biocatalyst displayed on the amylose resin which is known as a solid support showing potent binding‐affinity with MBP.     

Non‐dispersive absorption for CO2 capture: from the laboratory to industry

Research on capture and recovery of CO₂ has become a critical topic in the development of technological answers to the greenhouse effect. Conventional industrial processes do not fit into the philosophy of process intensification in which a radically new approach should lead to environmentally friendly methods with minimal use of natural resources and production of secondary waste. Conventional processes involve the use of large amounts of toxic organic solvents, such as diethylamine, and large equipment (e.g. absorption columns). Although CO₂ recovery began in industrial operation more than fifty years ago and, in spite of the clear potential for intensified processes demonstrated in the scientific literature, there is no real evidence that new processes for CO₂ recovery will achieve industrial implementation in the short term. In this perspective, the main limitations of membrane systems based on non‐dispersive absorption using porous membranes are outlined, in order to identify the main challenges that still have to be solved to achieve an industrially attractive process for CO₂ recovery. Copyright © 2011 Society of Chemical Industry     

Itaconic acid used as a versatile building block for the synthesis of renewable resource‐based resins and polyesters for future prospective: a review

Itaconic acid, a carbohydrate‐derived aliphatic dicarboxylic acid, is a potential chemical for the synthesis of renewable resource‐based resins and polyesters. Owing to environmental reasons, there is a gradual demand for renewable resources in the chemical industry. Conversely, as a rather underappreciated side effect of this growth, novel chemical building blocks are obtained, which are not commercially derived from petrochemical sources. In this respect, itaconic acid has attracted much attention and its trifunctional structure leads to the synthesis of novel polymeric materials. This review discusses the most relevant information for bio‐based resins and polyesters resulting from itaconic acid and distinctive properties for various commercial applications. © 2017 Society of Chemical Industry