Bench-scale Apparatus Research Articles

Preliminary Study on Mini-Modus Device Equipped with a Bioreactor to Purify and Oxygenate a Synthetic Effluent

To explore the possibility of recovering a polluted anoxic environment characterized by an elevated organic load, a bench-scale novel technology, called the module for the decontamination of units of sediment (MODUS), was studied. The bench-scale apparatus is able to aerate an effluent by a sparger that uses an air flow. The apparatus was implemented with a bioreactor to biodegrade a synthetic effluent made by glucose, urea, and potassium acid phosphate; an apparatus that will be here referred to as the BIOmini-MODUS. To test its performance, seven series of biodegradation experiments were done, each series corresponding to one of the seven different selected air flows in the range 5–20 L min−1. The purpose was to determine the best operative conditions for the BIOmini-MODUS, especially in terms of energy efficiency. These were found by studying eight parameters deemed particularly crucial: (1) dissolved oxygen concentration of the synthetic effluent, (2) time required to complete the substrate biodegradation, (3) air pressure (head losses) of the pumped air, (4) power needed to pump the air, (5) total energy used during a single biodegradation experiment, (6) biodegradation efficiency, (7) biological oxygen demand BOD as a function of time, and (8) the maximum biodegradation velocity reached by each biodegradation experiment. All of them, except BOD, were a function of the air flow. The air flow resulted in being particularly important to optimize the performance of the BIOmini-MODUS in terms of biodegradation velocity and oxygen concentration at the apparatus exit, in conjunction with energy efficiency. This last one, which showed a sharp maximum for an air flow of 10 L min−1, was determined on the basis of the biodegradation rate. At low air flows, a high biodegradation rate resulted in being a good parameter to indicate high energy efficiency; while, on the other hand, a high oxygen concentration resulted in being a good parameter to determine a high biodegradation rate.

Mitigation of firefighters’ skin burn injuries utilizing auxiliary measures

The improvement in the thermal resistance of firefighter’s outer garments has been traditionally achieved with the implementation of phase change materials or aerogel as an added protective measure. This study proposes supplementary novel cost-effective measures to enhance the thermal resistance of conventional firefighter outer garments. The proposed measures consist of auxiliary protective layers of meta-aramid fabric of a plain weave and a honeycomb structure. A custom built vertically oriented bench-scale apparatus was used to simulate extreme to life-threatening fire environments characterized in terms of an incident radiative flux of 84 kW/m2 and 126 kW/m2. The fluctuations in experimental heat flux density were treated by employing a Gaussian empirical model. The heat dissipation rate within the skin layers was predicted with a numerical model based on finite element methodology. The skin burns were classified with Henrique’s integral. The conventional outer garment when exposed to 84 kW/m2 and 126 kW/m2 resulted in a superficial second and third-degree burn. The auxiliary layers, in conjunction with the outer garment, mitigated second and third-degree burns. The meta-aramid fabric of a plain weave exhibited better thermal resistance than the honeycomb structure layer. The proposed measures reduced the epidermis temperature by 32%. An inner garment made of meta-aramid fabric is recommended to be worn concurrently with an outer protective suit for severe fire incidents due to its relative ease of use. Honeycomb structure layers are not recommended due to their weak structure and restriction in mobility.

Tandem Electrokinetic/Electrocatalytic Remediation of Pfas in Soils

Per-/polyfluorinated species (PFAS) are a class of widely used, highly stable chemicals that do not readily break down in the environment or human body. As a result of their widespread use and persistence in the environment, PFAS can be found in soil, air, and water at numerous sites across the United States. Recent work has linked exposure to some types of PFAS found in the environment to adverse health effects in humans. The bio-accumulative nature of PFAS along with the potential adverse health effects has provided strong motivation for active remediation of these emerging contaminants at environmental sites. Development of energy- and cost-efficient technologies for the in-situ treatment of PFAS-contaminated soils would greatly facilitate efforts to remediate these contaminated sites and alleviate the public health threat they represent.This talk will discuss recent efforts to develop a tandem electrokinetic/electrocatalytic technology for energy-efficient concentration and destruction of PFAS in contaminated soils. In this approach (Figure A), electrokinetic soil remediation technology is used to drive the PFAS contaminants to a localized area around the electrokinetic anode and electrocatalysis reactors situated near this electrokinetic anode degrade and destroy the concentrated PFAS species. Data will be presented describing the electrokinetic transport observed for various C4-C12 linear-chain PFAS in a Dayton, OH till soil on the bench scale (see Figure B). Experimental results to date suggest that larger PFAS species (above ~C6) experience sufficiently strong physicochemical attraction to the soil particles that electrokinetic transport is mostly or completely suppressed. Based on these results, current work is identifying ways to improve electrokinetic PFAS remediation by disrupting these PFAS-soil interactions in a fashion that is economically and environmentally favorable. Results demonstrating the ability to enhance electrocatalytic PFAS destruction through the use of pulsed-waveforms (relative to traditional direct current methods) will also be presented.Figure Caption. (A) Mechanism of tandem electrokinetic/electrocatalytic PFAS destruction. (B) Bench-scale apparatus for soil electrokinetics tests. Figure 1

Development of a bench-scale apparatus to assess thermal protective performance of garments under highly intensive heat-flux exposures

Thermal protective clothing protects emergency responders from fire hazards. The thermal protective performance of the multi-layer fabric is standardly evaluated at the average value of a 1–3-cal/(cm2s)-intensity range. Considering the magnitude of modern fire events, the range’s upper limit (3 cal/(cm2s)) was proposed to take into account a critical radiation condition and a bench-scale apparatus, capable of creating the critical experimental environment, was developed in this study. This instrument includes a vertical configuration heater with an active water-cooling part, a vertical orientation specimen-assembly with a measuring part, a movable specimen-holder and thermal shields operated by pneumatic pumps, an exhaust hood connected to a pan, a data acquisition system, heating-power and mechanical equipment controllers and a computer with in-house burn-injury analysis software. A preliminary test was conducted to determine a specimen-assembly position that both optimised the heat-source power, heater-capability and apparatus-sustainability, and subsequently validated the uniformity and consistency of irradiance on the test sample. To conduct repeatable measurements, an in-house program was used to operate the heater, specimen assembly and thermal shields semi-automatically, in a sequence. The software includes an algorithm that allows one to analyse heat transfers across human-skin layers and to assess the degree of burn injuries. This paper outlines a comprehensive process of creating an experimental environment for samples that need to be exposed to a critical thermal condition.

Reaction to fire of polymethylmethacrylate and polyvinylchloride under reduced oxygen concentrations in a controlled-atmospherecone calorimeter

Electrical cable sheaths are the most abundant fire load in nuclear power plants, mainly in rooms that are kept in under slight pressure. This configuration leads fires to grow in under-ventilated and vitiated conditions. Assessing fire threat involves characterizing the heat released, responsible for fire growth, and the smoke evolved, which may interact with sensitive components in the area. For that purpose, a revisited controlled-atmosphere cone calorimeter has been designed, set up, and coupled to a Fourier transformed infrared spectrometer and an electrical low-pressure impactor to measure simultaneously the evolved gases and aerosols, respectively. This bench-scale apparatus has been first qualified with polymethylmethacrylate. It has second been used to characterize polyvinylchloride cable sheath representative material reaction to fire in under-ventilated and vitiated conditions. It appeared that vitiation in under-ventilated fires lowers the heat release rate and the fuel mass loss rate.

A method to predict desiccation crack depth in a compacted clayey soil

Estimation of crack depths and spacing due to desiccation of clayey soils is needed to predict changes in mechanical or hydraulic properties in the cracked layer. These changes affect the infiltration of water, stability, and deformation of a soil mass. Desiccation cracks are associated with increasing suction due to moisture loss accompanied by restrained shrinkage, which results in tensile stresses in near surface soil layers. Cracks propagate when the developed tensile stresses exceed the tensile strength of soil. A simple analytical method is presented to predict crack depths in compacted clayey soil due to changes in matric suction with depth. The model equation is based on the Hookean elastic equation relating incremental strain to incremental stress and incorporates two stress state variables including net normal stress and matric suction. Input to the model equation includes the tensile strength and elastic parameters, and to complete the prediction of crack depth, the suction change profile of interest is needed. The method validity was investigated by comparing predicted crack depths to those observed in soil compacted in a bench scale apparatus for studying desiccation cracking. Tensile strength and elastic properties were determined from tests conducted on soil during desiccation under approximate uniaxial conditions. Predicted crack depths were obtained based on changes in suction interpreted from water content sensors at various depths in the soil bed and compared favorably to observed desiccation crack depths.

Exergy analysis of glycerol steam reforming in a heat recovery reactor

A detailed exergy analysis was performed for the steam reforming process of glycerol by means of a series of experiments in a bench scale apparatus. The reforming was conducted in a fixed bed reactor, which operated in heat recovery mode by extracting the demanded energy from hot exhaust gases provided by a diesel engine. In order to determine the role of the main operational parameters into the exergy efficiency of the studied process, the experiments were carried out with glycerol feed concentrations in water ranging from 10% up to 90% weight, whereas the outlet reactor temperature was varied from 600 °C up to 800 °C. Detailed exergy balances revealed a compromise between the exergy destruction within the reforming reactor and liquid separator versus the exergy losses associated to the tar and char outputs. This trade-off was favourable to the 50% and 70% glycerol feed concentration regimes and plateaus of about 74% exergy efficiency and 24 MJ/kg dry syngas exergy content were verified from 650 to 800 °C reactor temperatures.

Performance Evaluation of Phase Separation Process Using High-concentration AMP Promoted by MAPA for CO2 Capture

Reduction of the energy penalty and cost of CO2 capture from concentrated gas streams using amine-based solutions can be achieved by minimizing the energy penalty in the solvent regeneration process. High concentration 2-Amino-2-methyl-1-propanol (AMP) solution precipitates as a carbonate when enough CO2 has been absorbed. By sending the separated carbonate to the stripper, the sensible heat of regeneration can be reduced. However, previous testing using 50 weight percent AMP solution mixed with Piperazine (PZ) with solid-liquid separation showed that the CO2 recovery rate was limited to 65% due to the lack of PZ regeneration. To improve the CO2 recovery rate, a novel solution and injection process were developed. N-Methyl-1,3-diaminopropane (MAPA) was selected as an alternative promoter based on reaction rate testing. Various tests were employed to characterize the behaviour of the AMP/MAPA solution under CO2 capture and recovery conditions. The injection point was relocated to avoid the inhibition of CO2 absorption observed when CO2 semi-lean liquid was sent to the upper portion of the absorber. The CO2 recovery rate and the precipitation quantity were simulated using a model built in Aspen Plus®. The novel solution and injection set-up were evaluated experimentally by a bench-scale apparatus.

Effect of the Cone Heater Scale Compliant with the ISO 5660 Standard on Spatial Uniformity of Radiant Heat Flux

Physical quantities such as mass loss rate, heat release rate, and total heat release are often measured through a cone calorimeter (a representative bench-scale apparatus) and are primarily considered as values per unit area. Hence, the uniformity of radiant heat flux supplied by the cone heater to the specimen is very important with respect to the measurement results’ validity. In this study, on the basis of the ISO 5660 standard, the uniformity of radiant heat flux at the specimen surface was evaluated for the cone heaters used with the cone calorimeter. It is observed that a normal cone heater (NCH) compliant with the ISO 5660-1 standard satisfies the requirement of uniformity within a range of ± 2% in the central 5 cm × 5 cm area, but it has a large deviation of approximately 13% at the position corresponding to the edge of the specimen. In addition, the duration of NCH usage does not significantly affect the distribution of radiant heat flux. Furthermore, it is observed that a large cone heater compliant with the ISO/TC 5660-4 standard can supply moderately-uniform radiant heat flux over the entire surface area (10 cm × 10 cm) of the specimen.

Ignition of wildland fuels by idealized firebrands

Experiments were carried out in the Idealized-Firebrand Ignition Test (I-FIT), a bench scale apparatus specifically designed to test the ignition of forest fuel layers from a representative firebrand. A cylindrical heater was used to model the firebrand, which allowed to control the incident radiative heat flux on the specimen, from the critical heat flux up to 25 kW/m2, for five different porosities of the fuel layer. Experimental ignition delay times were interpreted based on a theoretical model of the radiative heating of the fuel layer. Radiative heat transfer within the fuel layer was modeled by using the P1 approximation. In the limit of small ignition delay times an analytical expression was derived to correlate the inverse of the ignition time to the incident heat flux. This analytical expression is used to obtain the ignition temperature and effective properties for the forest fuel layers, namely the product of the fuel volume fraction by solid fuel density and solid heat capacity. Analytical solutions were found to be consistent with experimental data and a correlation relating the inverse of the non-dimensional time-to-ignition to the non-dimensional heat flux is provided.

Advances in Nanoliposomes Production for Ferrous Sulfate Delivery.

In this study, a continuous bench scale apparatus based on microfluidic fluid dynamic principles was used in the production of ferrous sulfate-nanoliposomes for pharmaceutical/nutraceutical applications, optimizing their formulation with respect to the products already present on the market. After an evaluation of its fluid dynamic nature, the simil-microfluidic (SMF) apparatus was first used to study the effects of the adopted process parameters on vesicles dimensional features by using ultrasonic energy to enhance liposomes homogenization. Subsequently, iron-nanoliposomes were produced at different weight ratios of ferrous sulfate to the total formulation components (0.06, 0.035, 0.02, and 0.01 w/w) achieving, by using the 0.01 w/w, vesicles of about 80 nm, with an encapsulation efficiency higher than 97%, an optimal short- and long-term stability, and an excellent bioavailability in Caco-2 cell line. Moreover, a comparison realized between the SMF method and two more conventional production techniques showed that by using the SMF setup the process time was drastically reduced, and the process yield increased, achieving a massive nanoliposomes production. Finally, duty-cycle sonication was detected to be a scalable technique for vesicles homogenization.

Development of a High Pressure Dry Coal Feed System for a 100 kWt Oxy-Coal Reactor

Abstract A design concept to feed dry coal from a hopper to a 100 kWt pressurized oxy-coal (POC) reactor using CO2 at 2 MPa was developed using transient computational fluid dynamics (CFD) simulations and bench-scale measurements. The feed system was required to maintain a steady flow of gas and solids at a coal flowrate of approximately 3.8 g/s and a CO2-to-coal mass ratio in the range 1–2. A 5.08-cm diameter vertical coal hopper feeding into a 0.635-cm diameter horizontal pipe was used to represent key elements of the feed system. A fluidized bed concept was found capable of providing the desired coal flowrate and CO2-to-coal flow ratio. Use of separate fluidization and dilution flows allowed the coal flowrate and CO2-to-coal flow ratio to be controlled independently. The amount of coal transported from the hopper was dependent on the net CO2 flow in the hopper but independent of the CO2 dilution flow. Pipe exit coal flowrates were found to fluctuate at levels acceptable for steady burner operation. Tests from a bench-scale apparatus using Pittsburgh 8 coal with a median particle diameter of 50 µm and moisture content of 6% confirmed the feasibility of the fluidization design. However, for a given CO2 fluidization flowrate, experimental coal flowrates were lower than predicted coal flow, in part due to simplifying assumptions of dry, spherical coal particles and smooth piping in the simulations.

Iron and aluminum powder explosibility in 20-L and 1-[formula omitted] chambers

Metallic dusts with low values for maximum pressure Pmax and volume-normalized maximum rate of pressure rise KSt as determined in bench-scale apparatus have been labeled as “marginally explosible.” These dusts pose unique challenges because they may be shown to be explosible using standardized bench-scale apparatus, yet they may not be found to be explosible using larger standardized test chambers. Furthermore, some metallic powders produce higher KSt values with increasing test scale.Results and preliminary analysis stemming from a comprehensive experimental campaign involving selected iron and aluminum powders of varying specific surface area are presented.Fine-, medium-, and coarse-particle size iron powder with Siwek 20-L KSt values less than 45 bar⋅m/s were also found to be explosible in the Fike 1-m3 vessel. The coarse iron was only found to be non-explosible with the sub-75 μm fraction removed. The fine, medium, and coarse iron powders produced lower maximum rates of pressure rise across all concentrations in the 20-L chamber compared to the 1-m3 vessel. Fine-, medium-, and coarse-particle aluminum powders were also tested. The coarse aluminum powder could be exploded under the corresponding experimental conditions of 20-L chamber but not under the corresponding experimental conditions of 1-m3 chamber. The volume-normalized maximum rate of pressure rise for the finest aluminum powder was found to be overdriven in the 20-L vessel using an ignition energy of 10 kJ compared to tests performed with the same ignition energy in the 1-m3 vessel. An ignition energy of 5 kJ was found to be more appropriate for testing fine aluminum in the 20-L sphere. In contrast, the medium-particle size aluminum produced a KSt value substantially higher in the 1-m3 vessel compared to the 20-L chamber.

Rice Cultivation without Synthetic Fertilizers and Performance of Microbial Fuel Cells (MFCs) under Continuous Irrigation with Treated Wastewater

To obtain a high rice yield and quality for animal feed without synthetic fertilizers, an experiment with bench-scale apparatus was conducted by applying continuous irrigation with treated municipal wastewater (TWW). Uniform rice seedlings of a high-yield variety (Oryza sativa L., cv. Bekoaoba) were transplanted in five treatments to examine different TWW irrigation directions (“bottom-to-top” and “top-to-top” irrigation) and fertilization practices (with and without P-synthetic fertilizers) as well as one control that simulated the irrigation and fertilization management of normal paddy fields. The highest rice yield (14.1 t ha−1), shoot dry mass (12.9 t ha−1), and protein content in brown rice (14.6%) were achieved using bottom-to-top irrigation, although synthetic fertilizers were not applied. In addition, this subsurface irrigation system could contribute to environmental protection by removing 85–90% of nitrogen from TWW more effectively than the top-to-top irrigation, which showed a removal efficiency of approximately 63%. No accumulation of heavy metals (Fe, Mn, Cu, Zn, Cd, Ni, Pb, Cr, and As) in the paddy soils was observed after TWW irrigation for five months, and the contents of these metals in the harvested brown rice were lower than the permissible limits recommended by international standards. A microbial fuel cell system (MFC) was installed in the cultivation system using graphite-felt electrodes to test the capacity of electricity generation; however, the electricity output was much lower than that reported in normal paddy fields. Bottom-to-top irrigation with TWW can be considered a potential practice to meet both water and nutrient demand for rice cultivation in order to achieve a very high yield and nutritional quality of cultivated rice without necessitating the application of synthetic fertilizers.

Remediation of oil-based drill cuttings using low-temperature thermal desorption: Performance and kinetics modeling

A bench-scale apparatus was used for the low-temperature thermal desorption (LTTD) treatment of oil-based drill cuttings (OBDCs). The effects of treatment temperature, treatment duration, sand/OBDCs mixing ratio, and initial oil content on the LTTD treatment performance were investigated. It was found that the petroleum hydrocarbons (PHCs) were barely left in the high-oil-content drill cuttings after LTTD (at 300 °C for 20 min), and thus the overall soil health was improved. The desorption kinetics models of PHCs under various conditions were established, and it was found that the LTTD of OBDCs followed nonlinear least-squares exponential kinetics (adjusted R2 > 0.9). The energy consumption models of LTTD treatment under different temperatures were also developed. The modeling results are of practical guiding significance and useful for designing effective LTTD treatment systems of OBDCs.

Low cost bench scale apparatus for measuring the thermal resistance of multilayered textile fabric against radiative and contact heat transfer

Radiation is the main medium of heat transfer from fire to firefighter. The protective clothing a firefighter wears is required to have good capability to resist this incoming heat radiation. Various fibre, fabric and other materials offer different levels of protection against heat radiation. The instruments used to measure the protective capability of fabric against radiant heat are normally expensive and may unable to measure heat resistance behind each layer of a multilayer combination simultaneously. In the current study, a bench scale and easy-to-operate instrument has been developed to measure the radiative and contact heat protection performance of textile fabric/clothing in multilayered configurations. Normal wooden frames, domestic aluminum foil, free open source software and high precision temperature sensors are used to develop the instrument. This instrument can be a very useful tool to gain primary understanding of the radiative heat protection of any material in single or multilayered configuration.

Experimental Characterization of Heat Transfer to Vertical Dense Granular Flows Across Wide Temperature Range

Particle-based heat transfer fluids for concentrated solar power (CSP) tower applications offer a unique advantage over traditional fluids, as they have the potential to reach very high operating temperatures. Gravity-driven dense granular flows through cylindrical tubes demonstrate potential for CSP applications and are the focus of the present study. The heat transfer capabilities of such a flow system were experimentally studied using a bench-scale apparatus. The effect of the flow rate and other system parameters on the heat transfer to the flow was studied at low operating temperatures (<200 °C), using the convective heat transfer coefficient and Nusselt number to quantify the behavior. For flows ranging from 0.015 to 0.09 m/s, the flow rate appeared to have negligible effect on the heat transfer. The effect of temperature on the flow's heat transfer capabilities was also studied, examining the flows at temperatures up to 1000 °C. As expected, the heat transfer coefficient increased with the increasing temperature due to enhanced thermal properties. Radiation did not appear to be a key contributor for the small particle diameters tested (approximately 300 μm in diameter) but may play a bigger role for larger particle diameters. The experimental results from all trials corroborate the observations of other researchers; namely, that particulate flows demonstrate inferior heat transfer as compared with a continuum flow due to an increased thermal resistance adjacent to the tube wall resulting from the discrete nature of the flow.

Phosphorus and Nitrogen Treatment of Reservoir Water using Zeolite

Eutrophication in reservoir and tributaries causes obstruction of water flow and increased concentration of organic matter and plant production. The purpose of this project is to research about development of a cost-effective, affordable, efficient and portable Total Phosphorus (TP) and Total Nitrogen (TN) removal agent, transferrable across the target market to facility owners and individuals in the world. Two types of pellet composition were chosen for this project which is zeolite plus clay and the other one is clay only. Implementing a chemical adsorption technique of a clay-zeolite media is unique to the industry. The project outcome was intended to create and test a bench scale apparatus with engineered adsorption clay-zeolite media, and prepared for further field analysis, such as pH stabilization and many more. From the result analysis, we have found that as the contact time increases, the removal efficiency of the pellets also increases. It is clear that pellet with clay and zeolite composition has a better adsorption rate on removal efficiency about 53% for TP and 82% for TN rather than clay only pellet about 48% TP and 67% TN. Since the synthetic solution has a concentration of 5mg/L for both phosphorus and nitrogen, the only variables are pellet composition, pH, temperature and contact time. Both pellets have their pH increasing as the contact time increases.

On the discrepancy of modelling the heat transfer for pure natural convection

In the present study, buoyancy driven flow fields in a bench scale apparatus are experimentally investigated by means of a non intrusive measurement technique, here the 2D-2C particle image velocimetry (PIV). An electrically heated copper block was used to induce a plume. As the temperature at the surface of the heating source is the main driver for the fluid dynamics, the surface temperature field was measured by thermography. The experimental results are compared to simulations with the Fire Dynamics Simulator (FDS). Simulations with a prescribed, homogeneous distributed surface heat flux and a 3D thermal heat conduction with a volumetric heat source were carried out. The impact of both approaches on the resulting flow fields showed no significant deviations, however, both do not agree with the experimental data. Whereas the surface temperatures of the heating source and its vicinity are in a good agreement for the 3D heat transfer approach. This leads to the conclusion that the modelled heat transfer mechanism does not provide valid predictions in this setup.

Investigation of Flammability, Thermal and Toxic Hazards of Liquid Materials in Vehicles

In case of vehicle fires, oil leakage fires along with the emissions of heat and smoke represent significant fire risk for the combustion of whole vehicles and ambient environment. In present study, the bench-scale cone calorimeter apparatus was employed to conduct fire hazards analysis. Three typical flammable oils, namely OAT, ATF and GLF were used as experimental materials. The heating radiation levels were set from 15 kW/m2 to 40 kW/m2 in steps of 5 kW/m2. Specific parameters, such as ignition time (TII), heat release rate (HRR), total heat release (THR) and CO concentration, have been studied to provide a comprehensive fire behavior assessment of the oils. The ignition times have a liner relationship with external heat fluxes. And the critical heat fluxes (CHF) of ATF and GLF are 6.0 kW/m2 and 3.8 kW/m2, respectively. The derived HRP, FPI and FGI values of ATF remarkably indicate that this oil can contribute more thermal hazard while OAT has the lowest. However, FED values reveal highest toxic hazards of GLF. OAT is the safest materials in terms of three typical oils.