Bench-scale Tests Research Articles

The selective flotation behavior and adsorption mechanism of thiohexanamide to chalcopyrite

In this paper, thiohexanamide (THA) surfactant was synthesized and introduced as a collector for sulphide ores. The flotation behavior of THA to sulphide ores was investigated by micro-flotation tests, bench-scale tests and adsorption quantity measurements. The results demonstrated that compared to O-isopropyl-N-ethyl-thionocarbamate (IPETC), THA exhibited superior selectivity to chalcopyrite against pyrite and galena. In comparison with another chalcopyrite collector sodium isobutyl xanthate (SIBX), THA showed stronger flotation affinity to chalcopyrite. UV/vis spectra results illustrated that THA can selectively reacted with Cu+ than with Fe2+ or Pb2+. The adsorption mechanism of THA to chalcopyrite was evaluated by FTIR spectra, zeta potential measurements and XPS analysis. The conclusion was further confirmed by density functional theory (DFT) calculations. Two adsorption geometries were suggested, one with the formation of a four-membered ring complex, another with the connection between just Cu and S atoms.

Demonstration Plant of the Kawasaki CO2 Capture (KCC) System with Solid Sorbent for Coal-Fired Power Station

In a Kawasaki CO2 capture (KCC) system, CO2 in an exhaust gas is captured using a solid sorbent system with low-temperature steam. Because this system reuses the waste heat, it conserves energy in comparison with other conventional technologies. While a moving bed system makes it possible to apply the KCC technology to a large-scale plant, technology development at a large test facility is necessary. Therefore, this study investigates the application of the solid sorbent developed by Research Institute of Innovative Technology for the Earth (RITE) to the KCC moving-bed system for practical use. This study also evaluates the performance of the solid sorbent in a bench-scale test plant and preliminarily examines the installation at a 40 t-CO2/d-scaled pilot test plant to identify technological challenges at coal-fired power stations.

Evaluation of dry acid gas removal process on bench scale test facility coupled with syngas produced by O2/CO2-blown gasifier

Dry acid gas removal test facility that comprises of halide and sulfur control units was coupled with O2/CO2-blown gasifier to demonstrate performance and operability of the dry gas purification process for the oxy-fuel IGCC power generation with efficient carbon dioxide separation. The facility was operated for initial five desulfurization cycles of sequential operation of sulfidation, regeneration, and reduction. The duration of each step was fixed to three hours which includes the purge operation to change the gas condition from syngas to oxidative gas, and vice versa. The test facility has the sulfur removal unit equipped with three fixed-bed reactors. Honeycomb shaped desulfurization sorbent that was improved to prevent harmful carbon deposition was installed in those reactors. The cyclic operation results revealed that the unit could reasonably remove sulfur compounds in the sulfidation steps and released the absorbed sulfur during succeeding regeneration steps for the initial five cycles of operation. The spent sorbent did not suffered with carbon deposition and retained their performance on sulfur removal. The absorbed sulfur in the spent sorbent was adequately released in regeneration steps for further operation of desulfurization cycles. The performance and operability of the dry acid gas removal process was successfully demonstrated in the actual syngas operation test.

Detection of Oil Release in Unsaturated Soil and Estimation of Oil Infiltration Rate Using Hydraulic Control System and Water Content Sensor

Rapid detection of oil released from underground storage tanks and estimation of its flow rate allows for the prevention of further contamination or the limitation of the spread of contaminants. In this research, we developed a method for oil release detection by sensing volumetric water contents (VWC) in a hydraulic control system. Oil release detection tests were conducted at bench and pilot scales. In the bench-scale test, oil and water were released directly on top of the oil release detection system. In the pilot-scale test, the release detection system was installed in the soil and the oil was spilled on the soil surface. The new oil release monitoring system was capable of detecting the oil release using the VWC decrease (0.42 → 0.11 m3/m3). The infiltration of water did not affect the value of VWC. Sequential injection or mixture of oil and water also showed a decrease in VWC (0.42 → 0.12 m3/m3). The rate of VWC decrease was directly proportional (− 0.003 ml/min) to the rate of oil infiltration. A conceptual model was suggested to delineate the mechanism of oil release detection and to estimate the rate of oil infiltration. The detectability of the oil release in soil was also verified in the pilot-scale test (0.45 → 0.12 m3/m3). The rate of oil infiltration could be estimated using the slope of the measured VWC. The amount of time for oil infiltration through the soil and dispersion during the migration should be considered to analyze the VWC curve properly. These results showed that the oil release detection system can be used to monitor oil release and to determine the rate of oil infiltration by installation in the soil near an underground storage tank.

Homogeneous catalyst for in-situ hydrotreating of heavy oils

The upgrading of the physical and chemical properties of heavy oil by hydrotreating using a liquid Ni-Mo catalyst was studied through bench-scale tests aiming at developing "inside-reservoir" technology. The liquid Ni-Mo catalyst was synthesized by a very simple method consisting in preparing and mixing solutions at room temperature under acidic conditions. Mixtures of liquid Ni-Mo catalyst and heavy oil were evaluated in a 500-mL batch reactor at 350, 390 and 400 °C for 30, 60 and 90 min. The results showed that the liquid Ni-Mo catalyst improved the crude oil properties by increasing the API gravity from 12.5 to 22 and decreasing the kinematic viscosity from 13,490 to 72 cST at 15.6 °C; the sulfur content from 5.5 to 3.1% and the nitrogen content from 750 to 392 ppm were also reduced. Furthermore, the volume of gasoline and diesel by Simulated Distillation were increased to 8 and 14 vol. %, due to the change in chemical composition. Aromatic and saturated hydrocarbon compounds increased at the expense of asphaltenes and resins.

New water-based fire extinguishant: Elaboration, bench-scale tests, and flame extinguishment efficiency determination by cupric chloride aqueous solutions

A new aqueous fire-extinguishing agent (AFEA) – the 40% aqueous solution of CuCl2 – was elaborated. The AFEA was prepared by dissolving copper(II) chloride dihydrate in water. The resulting solution was characterized by a series of physicochemical methods. The ability of the CuCl2-containing AFEA to suppress the hydrocarbon flame has been investigated under conditions of an enclosed space according to the all-Union State Standard 3789 and open space by means of elaborated technique. The testing results have revealed a short-term exposure of the 40% aqueous solution of CuCl2 directly onto flame causes the efficient inhibition of fire. It has been ascertained that under conditions of the experiment, the extinguishment duration of the seat of fire (the special fire of B1 class) by the CuCl2-containing AFEA aerosol was 0.6 s; this is 26 times more efficient than the same extinguishment by water aerosol. The experimental ascertained values of the AFEA aerosol feed intensity (IAFEA) and the minimal expenses of the AFEA to extinguish the seat of fire of B1 class are 0.057 L⋅m−2⋅s−1 and 0.034 L⋅m−2, respectively. These data have become a reliable basis to explain the hydrocarbon flame suppression mechanism by aqueous solutions of copper(II) salts.

High-throughput analysis of photocatalytic reactivity of differing TiO2 formulations using 96-well microplate reactors

The rapid development of photocatalysts for water decontamination benefits from availability of sensitive platforms for screening photocatalytic reactivity. The standard approach typically involves quantifying the degradation of a single dye compound in a slurry system in individual beakers, which requires tedious photocatalyst separation and long operation time. We present a simple and efficient method for assessing the photocatalytic activity of different photocatalyst nanomaterials that eliminates the solid separation process. The 96-well microplate method demonstrated an improved applicability as a high-throughput screening method for photocatalytic reaction mechanisms using a wide range of chemical substrates (i.e., methyl orange, methylene blue, terephthalic acid, and β-nicotinamide adenine dinucleotide coenzyme) and photocatalyst concentrations (1–100 mg/L). By employing photocatalysts at lower concentrations compared to the slurry system, rapid screening was accomplished through direct spectrophotometric or spectrofluorometric measurements. The mass-normalized rate constants of dye degradation were used to determine the photocatalytic reactivity of three commercial TiO2 nanomaterials, which followed an order of SRM TiO2 1898 ≈ Degussa TiO2 P90 > Food-grade TiO2 E171. The extent of hydroxyl radical involvement in methyl orange degradation was estimated to be ∼74% by using radical scavengers in the microplate reactor. Given the utilization of low-concentration photocatalyst, this protocol may be used for evaluating photocatalytic reactivity and oxidative stress caused by photocatalyst exposure in an aquatic environment. We further evaluated photocatalytic reaction kinetics with respect to energetic and photonic efficiency. The method could greatly facilitate comparisons across different laboratories when quantifying photocatalytic reactivity and efficiency, which would aid in standardizing bench-scale photocatalysis testing.

Occurence and Prioritization of Pharmaceutical Active Compounds in Domestic/Municipal Wastewater Treatment Plants

In this study, pharmaceutically active compounds (PhACs) were analyzed in the influent and effluent of a domestic wastewater treatment plant in Turkey and a municipal wastewater treatment plant in Germany and the toxicity of these wastewaters were estimated using a toxic unit (TU) approach. A total of 21 and 32 PhACs were detected in the domestic wastewater and the municipal wastewater, respectively. The TUs estimated for PhACs in municipal wastewater were higher than the TUs estimated for PhACs present in domestic wastewater. The levels of the anti-anxiety drug, oxazepam were estimated to be in the high risk category (HQ > 10) in both wastewaters. In bench-scale tests with ozonation, the removals of four PhACs in the municipal wastewater were investigated. At a dose of 2mg/L ozone, 97%-98% of diclofenac and carbamazepine were removed. The lowest removal rate at 71% was observed for metoprolol.

Novel recycling process for lead-acid battery paste without SO2 generation - Reaction mechanism and industrial pilot campaign

This study proposes an innovative and environment-friendly method for recycling spent lead-acid batteries without SO2 generation. Iron-containing waste was employed as a sulfur-fixing agent to retain sulfur as ferrous matte, which eliminated the generation and emissions of gaseous SO2. This work investigated the thermodynamic and experimental feasibility and conversion mechanism of the method, and evaluated its industrial applicability. A bench-scale test showed direct recoveries of 93.5% and 97.7% in crude lead and ferrous matte for lead and sulfur, respectively. The phase transformation mechanism study indicated that metallic lead from the lead paste was extracted mainly through the sequence of PbSO4→C/CO PbS →Fe3O4 PbO →C/CO Pb. Sulfur in PbSO4 was thus first transferred to PbS and finally fixed as FeS. An industrial-scale pilot campaign was also conducted to confirm the feasibility and reliability of the new process.

A Proposed New Laboratory Protocol for Dispersant Effectiveness Testing Adapted for Subsea Dispersant Injection

The main objective of this study is to develop a new protocol for bench-scale dispersant effectiveness testing adapted for subsea dispersants injection (SSDI). The new approach includes turbulence conditions, dispersant injection techniques and quantification of effectiveness, more representative for a SSDI operation. Results from the new system are compared to dispersant effectiveness measured with established laboratory methods, used for screening dispersants for surface application. The most significant result is that the dispersant ranking obtained with the new test relevant for subsea releases was very different compared to the ranking obtained by screening methods used for surface application of dispersants. This strongly indicates that existing standard methods for dispersant effectiveness testing designed for simulating conditions relevant for surface application of dispersants, are less relevant for SSDI effectiveness testing and justify the need for a more relevant method. Such a Dispersant Injection Effectiveness Test (DIET) is suggested and documented in this study.

Effect of the High Temperature Resistant Nano-Coolant on Automotive Engine Operation

An engine nano-coolant without agglomeration was developed, which was heated to 120 degrees and kept for 15 consecutive days, and has good anti-corrosion, and better thermal conductivity in flow compared with the conventional engine coolant. The results of engine bench scale test, vehicle driving and construction machinery test and exhaust emission test show that the fuel saving rate of the car on the expressway is 5-15%, the fuel consumption of construction machinery decreases by 12.77%, and the temperature of the water tank decreases by 8.17°C on average in summer without the help of natural wind. In addition, the emission of CO and HC during the driving process also decreases by 7.8-13% and 0-19% respectively, which proves that nano-fluids can significantly increase engine combustion efficiency, prevent engine from overheating at high temperature and reduce exhaust emissions, and will replace the ordinary ethylene glycol-water products as a new type of engine coolant with high thermal conductivity.

Solketal production in a solvent-free continuous flow process: scaling from laboratory to bench size

Low-range adsorption mechanism kinetic model for solketal production was developed at lab-scale and validated in long-term bench-scale tests.

Small Pilot Test Results from a Polaris Membrane 1 MWe CO2 Capture System

To mitigate the harmful effects of global climate change, CO2 in combustion sources must be captured and either sequestered or utilized. Membrane technology is an attractive CO2 capture option because of advantages such as energy-efficient passive operation, small footprint, no hazardous chemical emissions, handling or storage issues, near instantaneous response, no steam use, and reduced water requirements. Working with the U.S. Department of Energy (DOE), Membrane Technology and Research, Inc. (MTR) has developed new membranes and process designs to recover CO2 from combustion gases. The Polaris™ class of membranes offer the highest combination of CO2 permeance and CO2/N2 selectivity of any commercial membrane today. These membranes are combined with a novel two-step process design that uses incoming combustion air to sweep membranes and recycle CO2 to the combustion process. The benefits of this two-step membrane design include an increased CO2 concentration to the membrane capture step and a reduction in the fraction of CO2 removal required by the capture step. Design calculations estimate that this membrane process can capture CO2 at a cost of <$40/tonne under partial capture conditions. Between 2012 and 2015, MTR operated a bench-scale test system at the U.S. National Carbon Capture Center (NCCC) in Wilsonville, AL testing commercial-scale Polaris membrane modules capturing 1 tonne CO2/day. Overall, this system accumulated a run time of over 11,000 hours, and demonstrated stable membrane performance while processing real coal-fired flue gas. The test system also operated as a field laboratory that allowed for evaluation of new membrane module designs and validation of advanced membranes under real world conditions. With this experience, MTR designed and built a scaled-up small pilot unit to treat 20 tonnes CO2/day from a slipstream at NCCC (equivalent to 1 MWe-scale coal-fired power generation). This system was operated for approximately 1,500 hours in 2015 over two different test campaigns. The small pilot membrane system exhibited stable performance and reached up to a 90% capture rate during operation in both winter and summer field test conditions. During the second test campaign, advanced Polaris sweep modules demonstrating higher packing density, lower pressure drop, and higher permeance were validated.

A contemporary review on plant-based coagulants for applications in water treatment

Conventional coagulants, like aluminium sulphate and ferric chloride, are used in potable water treatment and involve non-sustainable mining and transformation of raw materials for their production with costly sludge disposal. Natural coagulants are mostly obtained from bacteria, fungi, animals and plants and are classified as polysaccharide, amino-polysaccharide, poly-phenols and proteins-based substances. Plant-based coagulants extracted from Moringa oleifera, Strychnos potatorum Linn, Plantago ovate, Trigonella foenum graecum and Opuntia ficus indica are potential substitutes to chemicals mostly based on bench-scale testing. These are organic polymers and polyelectrolytes that are classified as cationic, anionic and non-ionic coagulants. This paper provides a historical and contemporary review of plant-based coagulants, their notable milestones achieved, chemistry involved, as well as bench, pilot and full scale trials, highlighting the effects of plant-based coagulants on physico-bio-chemical properties of raw water. Commercialisation constrains are also included and discussed.

Effect of Stoichiometry and Temperature on NOx Reduction by Reagent Injection in the Fuel-Rich Zone of Pulverized Coal Combustion

In this paper, the characteristics of NOx reduction by reagent injection into the fuel-rich zone (RIFR) in coal combustion were investigated, under high temperatures and reducing atmosphere conditions. The stoichiometry and temperature have a major influence on the chemistry of NO and NH3 reagent (ammonia or urea). Therefore, experiments were conducted on a bench-scale test system with urea solution as the reagent to investigate the key factors influencing NOx reduction, including primary stoichiometric ratio (SR1), temperature in the reaction zone, and normalized stoichiometric ratio (NSR) of the injected reagent. The results indicated that the primary stoichiometric ratio SR1 was the key parameter affecting the reduction of NOx emissions. Better NOx reduction was achieved with a decrease in the SR1 for bare air staging. However, there was no benefit for NOx reduction by reagent injection in the very fuel-rich zone (SR1 ≤ 0.75), which depended on the distribution of N-intermediates and initial NO concent...

Study of the importance of non-uniform mass density in numerical simulations of fire spread over MDF panels in a corner configuration

The distribution of mass density through the thickness of Medium Density Fiberboard (MDF) panels is known to be non-uniform. A few studies have previously investigated the influence of this non-uniform through-thickness density distribution on the thermal behavior of MDF panels in small-scale tests. This study assesses the significance of this material property on flame spread simulations in a medium-scale set-up, namely that of Single Burning Item (SBI) corner fire tests. Simulations are performed using FireFOAM 2.2.x, considering both uniform and non-uniform MDF material density profiles, using model-effective material properties determined from bench-scale pyrolysis tests conducted in a Fire Propagation Apparatus (FPA). The heat transfer from the gas phase is modeled by means of empirical expressions with adjusted parameters. The simulations are assessed against the results of several SBI experiments with MDF panels and a test with Calcium Silicate (CS) panels. When the non-uniform nature of the through-thickness density is taken into account, the fire growth prediction in terms of the total Heat Release Rate (HRR) is considerably different (20% higher peak HRR), mainly due to the characteristic high peak mass loss rate at the initiation of pyrolysis of MDF material, resulting from the higher mass density near the surface of the panels. Furthermore, total heat fluxes on the panels, lateral flame spread, surface pyrolysis and through-thickness char formation visibly depend on the non-uniform distribution of mass density, particularly in regions further away from the corner where the influence of thermal attack from the burner is less dominant. A new diagnostic is proposed for determining the pyrolysis front location and spread on the surface of the charring panels.

Assessing the structural integrity of carbon-fibre sandwich panels in fire: Bench-scale approach

The fire resistance of lightweight sandwich panels (SW) with carbon fibre/epoxy skins and a poly(methacryl imide) (PMI) foam core is investigated in compression under direct application of a severe flame (heat flux = 200 kW m−2). A bench-scale test procedure was used, with the sample held vertically. The epoxy decomposition temperature was quickly exceeded, with rapid flash-over and progressive core softening and decomposition. There is a change in failure mode depending on whether the load is greater or less than 50% of the unexposed failure load, or in other words if one or two skins carry the load. At high loads, failure involved both skins with a single clear linear separation across each face. There is an inflection in the failure time relationship in the ∼50% load region, corresponding to the time taken for heat to be transmitted to the rear face, along with a change in the rear skin failure mode from separation to the formation of a plastic hinge. The integrity of the carbon front face, even with the resin burnt out, and the low thermal diffusivity of the core, both play key roles in prolonging rear face integrity, something to be borne in mind for future panel design. Intumescent coatings prolong the period before failure occurs. The ratio of times to failure with and without protection is proposed as a measure of their effectiveness. Apart from insulation properties, their adhesion and stability under severe fire impact play a key role.

Start-up of a pilot scale anaerobic reactor for the biogas production from the pineapple processing industries of Belgium

In this study, a pilot scale continuous stirred-tank reactor (CSTR) was used to investigate the startup of an anaerobic system, followed by a bench scale test to analyze the biogas production. Wastewater from pressing and crushing leaves of the pineapple crop was used as a substrate in the CSTR. During the study period, the organic loading rate (OLR) was gradually increased and parameters such as volatile fatty acids (VFA), temperature, pH, bio-gas production and chemical oxygen demand (COD) were carefully monitored. The result of the bench scale test showed the potential of the wastewater for producing the biogas. The study indicated an OLR of 3.8 g COD/L/d, and a maximum biogas production of 3.3 L/d, with an average of 2.8 L/d. The COD removal efficiency reached its highest peak with a value of 64.8%, when the OLR was 3.43 g COD/L with the hydraulic retention time (HRT) of 20 days. Based on the measurements made throughout the test period, there were no indications of the presence of toxic elements in the wastewater, which could inhibit the anaerobic degradation process. This study is an attempt to provide a vigorous solution for the pineapple industry wastewater scenario, thereby aiming at sustainable energy production.

The Impact of Mechanically-Imposed Shear on Clogging, Fouling and Energy Demand for an Immersed Membrane Bioreactor.

The impact of the application of mechanically-imposed shear on the propensity for fouling and clogging (or “sludging”—the agglomeration of sludge solids in the membrane channel) of an immersed flat sheet (iFS) membrane bioreactor (MBR) was studied. The bench-scale test cell used contained a single flat sheet fitted with a crank and motor to allow the membrane to be oscillated (or reciprocated) vertically at a low rate (20 RPM). The membrane was challenged with sludge samples from a local MBR installation treating petroleum industry effluent, the sludge having previously been demonstrated as having a high sludging propensity. Sludging was measured by direct visual observation of membrane surface occlusion by the agglomerated solids, with fouling being notionally represented by the rate of transmembrane pressure increase. Results demonstrated membrane reciprocation to have a more beneficial impact on sludging amelioration than on suppressing fouling. Compared with the stationary membrane, sludging was reduced by an average of 45% compared with only 13% for fouling suppression at the reference flux of 15 L·m−2·h−1 applied. The specific energy demand of the mechanical shear application was calculated as being around 0.0081 kWh·m−3, significantly lower than values reported from a recent pilot scale study on a reciprocated immersed hollow fibre MBR. Whilst results appear promising in terms of energy efficiency, it is likely that the mechanical complexity of applying membrane movement would limit the practical application to low flows, and a correspondingly small number of membrane modules.

Fire behavior of lithium-ion battery with different states of charge induced by high incident heat fluxes

Numerous accidents including fires and explosions occurring in transportation and storage of batteries enhance the need of studying the fire performances on batteries. In the current work, series bench-scale tests are conducted using a cone calorimeter to explore the fire behavior of lithium-ion battery. The influence of two key factors, namely state of charge (SOC) and incident external heat flux, on the battery fire characteristics is especially investigated. Combustion behavior, time to ignition (TTI), heat release rate (HRR) and fire risk assessment are obtained. The battery with higher SOC under high incident heat flux presents a fierce combustion process and higher surface temperature than the others. It is noteworthy that the time to ignition and time to peak HRR (TTP) decrease with the SOC, whereas the peak HRR (pHRR) and total heat release (THR) increase overall. On the whole, the increment of incident heat flux causes the decrease in TTI and TTP, while the pHRR and THR increase at higher incident heat flux. And the values of TTI agree well with the classical ignition model. Finally, the fire risk of battery with different SOCs under various incident heat fluxes is also highlighted.