Large Laboratory Scale Research Articles

Two-scale blockage correction for an array of tidal turbines

It has been shown theoretically that tidal fences consisting of multiple turbines placed side-by-side can makeuse of constructive interference (local blockage) effects to raise the energy extraction efficiency of the fenceabove that of the Betz limit applicable to unblocked flow problems. For the two-scale problem of a longarray of turbines partially spanning the width of a much wider channel (vanishing global blockage) theefficiency of energy extraction, normalised on the undisturbed kinetic energy flux, rises from the Betz limitof 0.593 to the partial fence limit of 0.798 [1]. Experiments on pairs of side-by-side turbines at largelaboratory scale [2] have confirmed the important aspects of the underlying partial fence theory and thatsome of the performance benefits offered by constructive interference effects can be achieved in practice.
 Experimental validation in wind tunnels, towing tanks and other laboratory facilities are however prone toglobal blockage effects not seen in full-scale open flows due to the close proximity of flow boundaries to thebody. These global blockage effects modify the thrust and power performance of the turbines, such thatcorrections to experimental curves are necessary to either translate laboratory-scale experimental results tofull-scale conditions, or to calculate the expected loads and power on tidal turbines deployed in blocked-flowconditions [3][4]. The difficulty applying blockage corrections to turbine arrays is the non-linear interactionbetween local and global blockage. These two effects cannot be simply decoupled as for various turbine tip-to-tip spacings (affecting local blockage), changes in the global blockage have a different impact on turbineperformance.
 A number of blockage corrections have been developed for single turbines operating in blocked flowconditions. These corrections typically seek to describe an equivalent free-stream velocity which, in theabsence of global blockage, would result in the same thrust and velocity through the turbine as in the blockedcase. Thrust and power curves are then scaled non-linearly with the ratio of the experimental tank velocityand the equivalent free-stream velocity [5]. These single turbine blockage corrections can however onlyaccount for global blockage, and simplifications must currently be made based on the assumption that globaland local blockage effects can be linearly decoupled [2].
 This work therefore presents an analytical blockage correction for co-planar arrays of tidal turbines based ontwo-scale momentum theory [1]. This correction is then compared to other models, particularly for turbinearray experimental test data. Finally, RANS computations for a turbine array at various global blockageratios is compared to the analytical model, demonstrating its validity. A particularly useful aspect of thetheoretical model is to allow for experimental quantification of the local-blockage effect for finite lengthfences. For instance, doubling the fence length doubles the global blockage, but increases in fence thrust andpower cannot be attributed only to the change in global blockage due to non-linear coupling. This correctionallows for a decoupling of these two effects, such that the local blockage effect can be isolated andquantified.

Tidal Turbine Benchmarking Project: Stage I - Steady Flow Experiments

The tidal turbine benchmarking project, funded by the UK's EPSRC and the Supergen ORE Hub, has conducted a large laboratory scale experiment on a highly instrumented 1.6m diameter tidal rotor. The turbine is instrumented for the measurement of spanwise distributions of flapwise and edgewise bending moments using strain gauges and a fibre Bragg optical system, as well as overall rotor torque and thrust. The turbine was tested in well-defined flow conditions, including grid-generated freestream turbulence, and was towed through the 12.2m wide, 5.4m deep long towing tank at Qinetiq’s Haslar facility. The turbine scale was such that blade Reynolds numbers were Re=3x10^5 and therefore post-critical, whilst turbine blockage was kept low at 3.1. In order to achieve higher levels of freestream turbulence a 2.4m by 2.4m turbulence grid was towed 5m upstream of the turbine. Measurements to characterise the grid generated turbulence were made at the rotor plane using an Acoustic Doppler Velocimeter and a five-hole pressure probe. An elevated turbulence of 3.1% with homogeneous flow speed across the rotor plane was achieved using the upstream turbulence grid. The experimental tests are well defined and repeatable, and provide relevant data for validating models intended for use in the design and analysis of full-scale turbines. This paper reports on the first experimental stage of the tidal benchmarking programme, including the design of the rotor and comparisons of the experimental results to blade resolved numerical simulations.

Tidal Turbine Benchmarking Project: Stage I - Steady Flow Blind Predictions

This paper presents the first blind prediction stage of the Tidal Turbine Benchmarking Project being conducted and funded by the UK's EPSRC and Supergen ORE Hub. In this first stage, only steady flow conditions, at low and elevated turbulence (3.1%) levels, were considered. Prior to the blind prediction stage, a large laboratory scale experiment was conducted in which a highly instrumented 1.6m diameter tidal rotor was towed through a large towing tank in well-defined flow conditions with and without an upstream turbulence grid. Details of the test campaign and rotor design were released as part of this community blind prediction exercise. Participants were invited to use a range of engineering modelling approaches to simulate the performance and loads of the turbine. 26 submissions were received from 12 groups from across academia and industry using solution techniques ranging from blade resolved computational fluid dynamics through actuator line, boundary integral element methods, vortex methods to engineering Blade Element Momentum methods. The comparisons between experiments and blind predictions were extremely positive helping to provide validation and uncertainty estimates for the models, but also validating the experimental tests themselves. The exercise demonstrated that the experimental turbine data provides a robust data set against which researchers and design engineers can test their models and implementations to ensure robustness in their processes, helping to reduce uncertainty and provide increased confidence in engineering processes. Furthermore, the data set provides the basis by which modellers can evaluate and refine approaches.

Semicontinuous Process of Rare Earths Recovery from End-of-Life NdFeB Magnets on a Large Laboratory Scale

Hydrometallurgical methods for NdFeB recycling typically consist of several unit operations and require the extensive use of energy, water and chemicals which may negatively affect the applicability of these methods on an industrial scale. Based on the data from our previous studies, a simplified process of rare earth elements (REE) recovery from spent NdFeB magnets was developed further. The possibility of regenerating the leaching agent, as well as water recovery, in the process was investigated. This study also investigates a possibility of scaling up the recycling process developed on a laboratory scale. The leaching and precipitation stages were tested on a larger scale, where about 1 kg of end-of-life magnets was used as feed to the leaching step. In this study, end-of-life magnets were obtained from the manual disassembly of computer hard disc drives. After disassembly, the magnets were demagnetized, broken into pieces and fed to the leaching process. In the following step, rare earths were precipitated in the form of oxalates. The rare earths’ precipitation efficiency reached a maximum of 95.6%. The results showed that the co-precipitation of Fe highly depends on the amount of oxalic acid used as the precipitant. Smaller losses of Fe were achieved while using a stoichiometric amount of oxalic acid in relation to the REE present in the solution. At the end of the investigated process, rare earth oxalates were calcinated to oxides and their purity was investigated. The recirculation of a solution after oxalate precipitation and acid regeneration was tested with hydrochloric and sulfuric acids used as leaching agents. Solution recirculation was found to be possible only in the case of hydrochloric acid.

Soluble Papain to Digest Monoclonal Antibodies; Time and Cost-Effective Method to Obtain Fab Fragment.

Antigen binding fragments (Fabs) used in research (e.g., antibody mimetics, antibody-drug conjugate, bispecific antibodies) are frequently obtained by enzymatic digestion of monoclonal antibodies using immobilised papain. Despite obtaining pure Fab, using immobilised papain to digest IgG has limitations, most notably slow digestion time (more than 8 h), high cost and limited scalability. Here we report a time and cost-effective method to produce pure, active and stable Fab using soluble papain. Large laboratory scale digestion of an antibody (100 mg) was achieved using soluble papain with a digestion time of 30 min and isolated yields of 55–60%. The obtained Fabs displayed similar binding activity as Fabs prepared via immobilised papain digestion. Site-specific conjugation between Fabs and polyethylene glycol (PEG) was carried out to obtain antibody mimetics FpF (Fab-PEG-Fab) indicating that the native disulphide bond had been preserved. Surface-plasmon resonance (SPR) of prepared FpFs showed that binding activity towards the intended antigen was maintained. We anticipate that this work will provide a fast and less costly method for researchers to produce antibody fragments at large scale from whole IgG suitable for use in research.

High-Solids, Solvent-Free Modification of Engineered Polysaccharides.

The nature-identical engineered polysaccharide α-(1,3) glucan, produced by the enzymatic polymerization of sucrose, was chemically modified by acylation with succinic anhydride. This modification reaction was initially performed at the micro scale in a TGA reactor to access a range of reaction conditions and to study the mechanism of the reaction. Subsequently, the best performing conditions were reproduced at the larger laboratory scale. The reaction products were characterized via coupled TGA/DSC analysis, FT-IR spectroscopy, solution viscosity and pH determination. The acylation path resulted in partially modifying the polysaccharide by altering its behavior in terms of thermal properties and solubility. The acylation in a solvent-free approach was found promising for the development of novel, potentially melt-processable and fully bio-based and biodegradable ester compounds.

Proppant transport in a planar fracture: Particle image velocimetry

Particle Image Velocimetry (PIV) is a well established technique used to measure displacements in fluids. Proppant transport and placement is a crucial phase in the process of well completion to stimulate production in gas and oil reservoirs. Proppant (a granular material) is injected along fluids during hydraulic stimulation to prop fractures open after hydrocarbon production is initiated. This work presents results on the use of PIV for the study of the transport of proppant in a large laboratory scale flat vertical fracture. Velocity and vorticity profiles were analyzed for different flow rates during the transport and settlement of the proppant inside the fracture. High flow rates, compatible with field operations are achieved in this setup. The results indicate that vortexes are present in a large portion of the system and that a non-linear interplay between the settling dune and the main vortex seems to determine the time at which a fast dune growth occurs in the fracture.

Advanced purification platform using circularly permuted caspase‐2 for affinity fusion‐tag removal to produce native fibroblast growth factor 2

AbstractBACKGROUNDRecombinant proteins produced for use as biopharmaceuticals need to harbor their native N‐terminus. A drawback in expression of recombinant proteins as fusion proteins with an affinity fusion‐tag is that enzymatic or chemical processing is required to trim the artificial tag and release the true protein of interest. In many cases, however, this processing step generates an incorrect N‐terminus.RESULTSHuman fibroblast growth factor 2 (FGF2) was expressed as a fusion protein in Escherichia coli fed‐batch cultivations. The protein of interest (POI) carried an N‐terminal affinity fusion‐tag which enabled purification via affinity chromatography. After enzymatic removal of the affinity fusion‐tag with a circularly permuted human caspase‐2 (cpCasp2), the POI was further purified using subtractive affinity chromatography. Mass spectrometric analysis confirmed the authentic N‐terminus of the POI. The generated POI was highly pure with 42 ppm host cell protein, 3.7 μg mL−1 dsDNA and ~ 1000 EU mL−1 endotoxin. Only a small number of E. coli host cell proteins were co‐purified with the POI. Because of the high specificity of the novel protease cpCasp2, no off‐target cleavage could be observed.CONCLUSIONOur findings demonstrate that cpCasp2 can be used for the production of native proteins using a fusion‐protein process. This represents a first case study at large laboratory scale for the production of an industrially relevant protein. This technology constitutes the basis of a highly scalable cpCasp2‐based platform fusion protein process (CASPON technology) purification platform. © 2021 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Modelling VOCs Emissions in Coal Fired Power Stations using Perfectly Stirred Reactor Approach

The main objective of this study is to evaluate the emissions of volatile organic compounds (VOCs) from coal-fired power stations. A quantitative understanding of the chemistry controlling the formation and destruction of these intermediate species is a prerequisite for the realistic modelling of pollutant formation in flames. Therefore, well investigated skeletal reaction mechanism has been built and introduced into perfectly stirred reactor model in order to accomplish prediction of some of these hazardous important intermediate species. This can be great help in considering lack of experimental VOCs data from fossil fuel fired power stations. Predicted results have been validated against ICSTM Furnace data where possible. The performance of the model against the large laboratory scale experimental data has resulted in considerable confidence in the use of this model for a full-scale boiler configuration. But, more confidence will be forthcoming from an increase in the amount of validation data, which is unluckily lacking at the moment. Furthermore, the model can be used in order to provide deeper insight into the formation processes of VOC species emitted from coal-fired power stations. However, this can be accomplished far better by including more elementary reactions into the skeletal reaction mechanism.

Production of phosphorus biofertilizer based on the renewable materials in large laboratory scale

AbstractThis paper discusses the effect of the utilization of Bacillus megaterium in the microbial solubilization process where poultry bones or ash were used as a source of renewable phosphorus. The process was performed in a large scale laboratory. The pH of the solution decreased during one-week solubilization, which had a direct influence on the increased concentration of phosphorus determined in the solution. It was proved that the phosphorus concentration in the solution was significantly correlated with the biomass concentration and pH. The trial allowed verification of the suitability of the method to prepare two P fertilizers: one based on poultry bones and one on ashes. The elemental analysis of their composition suggests that the bones are a P-bearing resource with properties better than ash. That enables for more efficient scaling-up the solubilization although the concentration of total phosphorus was comparable in both cases. The total amount (100%) of phosphorus was present in a form available to plants in the formulation based on the poultry bones, while 64% of plant available phosphorus was present in the formulation based on the ash. The concentration of Cd was significantly lower in the case of fertilizer based on bones with respect to ash.

Novel hydro-electrometallurgical technology for simultaneous production of manganese metal, electrolytic manganese dioxide, and manganese sulfate monohydrate

The main stages of a novel hydro-electrometallurgical technology for simultaneous production of electrolytic manganese metal, electrolytic γ-MnO2, and manganese sulfate monohydrate (MnSO4∙H2O) were tested at a large laboratory scale. The unified flow sheet comprised large and small process loops. The large loop included: concentrated sulfuric acid leaching of ore obtained by high-temperature reduction of manganese oxide ore; hydrolytic and sulfide purification of MnSO4 solution; production of crystalline manganese sulfate monohydrate obtained by high-temperature autoclave treatment of purified concentrated MnSO4 solution; feeding of hot spent MnSO4 solution from the autoclave as anolyte to an AMI-7001S anion membrane-separated electrochemical reactor where γ-MnO2 was produced on titanium anodes. The small process loop included preparation and correction of the catholyte composition using MnSO4∙H2O crystallized in the autoclave, from which electrolytic manganese metal was deposited on titanium cathodes. A heat pump was used to maintain the necessary temperature difference between the anolyte and catholyte. The energy consumed by the heat pump was half that obtained using an electrical current heating device. Electrical power consumptions for the production of manganese metal, manganese dioxide, and manganese sulfate monohydrate were 9.67 Wh/g, 3.75 Wh/g, and 0.884 Wh/g, respectively.

Examinations of the sulfur emission from pulverized lignite fuel, under pyrolysis and oxy-fuel combustion condition

Problem of gas emission as NOX, SOX, heavy metals from fossil fuel combustion process is still under study. Especially the oxy-condition effect on gas emissions from oxy-fuel requires more analysis and research. This paper focuses on SO2 and SO3 behaviour investigation during air and oxy-fuel combustion processes, and formation of H2S and SO2 from N2 and CO2 atmosphere. The research focuses especially on Polish medium sulphur coals. In the paper selected brown coals were examined on the content of total sulphur. During the tests campaign one type of lignite, predried to Mraw = 15% was a subject of pyrolysis at 800 and 1000 °C under N2 and CO2 atmosphere, and further combusted in three different atmospheres: air atmosphere, and two different oxy atmospheres with O2/CO2 ratios, equal 25/75% and 30/70% (vol.). Tests were carried out on an isothermal flow reactors (IFR) in a large laboratory scale. The influence of the CO2 atmosphere in oxy-condition in comparison with to the air atmosphere on SO2, SO3 emission intensity was determined. The results showed that the change of atmosphere from the air atmosphere to oxy atmosphere and increase of oxygen concentration in O2/CO2 combustion atmosphere results in the increase of the conversion ratio ofsulphur from solid phase to a the gas phase for the lignite. During the pyrolysis process it is mainly the H2S that is released in the gaseous form.

Microfluidic devices containing thin rock sections for oil recovery studies

While there has been a shift towards renewable energy sources, oil remains an important source of not only energy but also raw materials. Oil recovery is currently an inefficient process with as much as 50% of the original oil remaining in a field. Improvement of oil recovery techniques requires a model system that is both chemically and physically representative to achieve accurate results. Current large laboratory scale systems use large cores drilled from target rock and large, high-pressure systems to recreate oil recovery systems. The cores and associated equipment required to accurately model oil recovery are expensive and time consuming to obtain and operate. As a result, there has been a continual quest to develop alternative solutions that are faster, less complicated, and less expensive while still providing accurate representation of reservoirs. An alternative to large-scale models are optically transparent two or three-dimensional microfluidic devices. Several examples of microfluidic devices used to study oil recovery processes have been published. Unfortunately, most microfluidic devices require complicated fabrication techniques, inaccurately replicate the reservoir rock surface chemistry and geometry, and are made from materials not representative of surfaces found in oil reservoirs. Herein, the Flow On Rock Device is described as an easy to fabricate microfluidic device that acts as a bridge between fully synthetic microfluidics and large laboratory models due to incorporation of reservoir rock samples directly into the microfluidic device. Results of flooding studies are presented on shale and sandstone models as an example of the potential for this system in studying oil recovery.

Chemical-free Processing of Sweet Sorghum Juice of Cultivar Sucrosorgho 506

The development of sweet sorghum syrup producing technology for the juice of cultivar Sucrosorgho 506 was completed. The applicability of different existing syrup production technologies including sugar beet-based sugar production technology, and sugar cane processing technology was also tested. The new chemical-free syrup production technology was realized at laboratory-scale and large laboratory-scale. The proposed technology offers a chemical free separation and concentration of carbohydrates, and consists of centrifugal separation; ultrafiltration extended with an approved sterilization followed by nanofiltration to separate carbohydrates and inorganics, and finally a vacuum evaporation to reach syrup state. By using this technology the initial glucose:fructose:sucrose ratio could be preserved in the syrup, therefore not limiting its further use. The possible food application was established by sensory analysis. It was revealed that the syrup produced via the developed process obtained the most attractive character that enables the opportunity to use as natural sweetener.

Screening of native S. cerevisiae strains in the production of Pajarete wine: a tradition of Atacama Region, Chile

ABSTRACTPajarete is a Chilean wine with an appellation of origin. Although it has organoleptic properties, intensive utilization of Saccharomyces cerevisiae commercial yeast through the years has presumably produced the loss of native strains that may be associated with Pajarete oenologic uniqueness. In order to evaluate the effect of re-incorporation of indigenous strains into Pajarete winemaking, native S. cerevisiae strains were isolated and selected based on their properties shown during small and large laboratory scale fermentation, and then evaluated in industrial bioreactors. From an initial set of 312 isolates, a single native strain was selected based on taxonomy, fermentation performance, aroma, residual sugars, and production of alcohol for incorporation into market scale.

Two-Step Electrochemical Intercalation and Oxidation of Graphite for the Mass Production of Graphene Oxide.

Conventional chemical oxidation routes for the production of graphene oxide (GO), such as the Hummers' method, suffer from environmental and safety issues due to their use of hazardous and explosive chemicals. These issues are addressed by electrochemical oxidation methods, but such approaches typically have a low yield due to inhomogeneous oxidation. Herein we report a two-step electrochemical intercalation and oxidation approach to produce GO on the large laboratory scale (tens of grams) comprising (1) forming a stage 1 graphite intercalation compound (GIC) in concentrated sulfuric acid and (2) oxidizing and exfoliating the stage 1 GIC in an aqueous solution of 0.1 M ammonium sulfate. This two-step approach leads to GO with a high yield (>70 wt %), good quality (>90%, monolayer), and reasonable oxygen content (17.7 at. %). Moreover, the as-produced GO can be subsequently deeply reduced (3.2 at. % oxygen; C/O ratio 30.2) to yield highly conductive (54 600 S m-1) reduced GO. Electrochemical capacitors based on the reduced GO showed an ultrahigh rate capability of up to 10 V s-1 due to this high conductivity.

Aspergillus terreus treated rice straw suppresses methane production and enhances feed digestibility in goats.

The objectives of this study were to test the efficacy of producing lovastatin in rice straw treated with Aspergillus terreus in larger laboratory scale following the procedure previously reported and to investigate the effectiveness of the treated rice straw containing lovastatin on methane mitigation in goats. The concentration of lovastatin in the treated rice straw was 0.69 ± 0.05g/kg dry matter (DM) rice straw. Our results showed that supplementation of lovastatin at 4.14mg/kg BW reduced methane production by 32% while improving the DM digestibility by 13% (P < 0.05) in goats fed fermented rice straw compared to those fed untreated rice straw. Populations of total methanogens and Methanobacteriales species were significantly reduced (P < 0.05) while the population of total bacteria and Ruminococcus albus were increased in the treatment group (P < 0.05). Our results demonstrated that lovastatin in the treated rice straw acted specifically on the methanogens by inhibiting the activity of HMG-CoA reductase in the methanogens' cell membrane biosynthesis pathway and thus the growth of rumen methanogens as previously reported. This study provides a simple yet practical approach to mitigate enteric methane production particularly in the developing countries which depend heavily on the use of agro-biomass such as rice straw to feed their ruminant animals.

Inline method of droplet and particle size distribution analysis in dilute disperse systems

In the present article a measurement method of particle size distributions (PSD) in industrial installations which use a dispersed phase of low concentration (like spray dryers or spray scrubbers) is introduced. A new type of inline-measurement system has been developed and designed to work in spray drying conditions. A standard digital camera is used to record shadows of flowing particles inside the spray drying chamber. Collected images were analyzed by a newly developed software which recognizes particles only in the focus area and eliminates several types of artifacts. The constructed prototype of the PSD inline-analyzer was installed and used to monitor large laboratory scale spray dryer. All data collected by the designed system during the spray drying experiments were compared with data measured with an offline reference system to show accuracy of the new measurement technique.

Scale-Up Synthesis of Hexabenzylhexaazaisowurtzitane, an Intermediate in CL-20 Synthesis

After successful synthesis of hexabenzylhexaazaisowurtzitane (HBIW) on a laboratory scale (0.25 L reactor), it was performed on a multilaboratory scale (10 L reactor) and subsequently in an experimental installation in which a 300 L reactor was built. Seven syntheses were carried out in the unit on a pilot scale to produce 250 kg of HBIW. The pilot-scale syntheses ran with a yield comparable to those observed for the processes conducted on a large-laboratory scale. Some modifications were suggested that allowed for reduction of the HBIW weight unit by approximately 50%.

Mercury removal by mild thermal treatment of coal

A new technology for removing mercury from coal by mild thermal coal treatment using arotary kiln is presented. Experiments performed at the large laboratory scale show that 93% of the mercury is removed; moreover, the thermal properties of the fuel obtained from the process are also improved. In this article, we describe the physicochemical characteristics of the fuel under the test conditions and the properties of the products obtained during the removal process. The experiments were performed in an appropriately modified test system, and the net mass and energy losses do not exceed 5%. An economic analysis indicates that the proposed technology is cost-competitive with existing methods for removing mercury from flue gases after combustion.