Effect Of Solids Concentration Research Articles

沉积物磷形态分析的固体浓度效应

以渤海埕岛油田区沉积物样品为例，探讨沉积物无机P形态分析过程中的固体浓度效应。4步顺序提取不同固体浓度(0.1 g/50 mL和0.2 g/50 mL)沉积物中的无机P，结果表明：沉积物中HCl-P含量最高，其次为BD-P和OH-P，含量最少的是loosely-P；沉积物磷形态分析过程中存在显著的固体浓度效应，表现为随着沉积物固体浓度增大，测得各形态P含量减少；沉积物中不同形态P受固体浓度的影响程度不同，强碱或强酸作为提取剂能有效抑制固体浓度效应，但不能完全消除。 We performed inorganic phosphorus (P) fractionation experiments of the sediments sampled from Chengdao oil field of Bohai, to explore the solid concentration effect on the process of sediments inorganic P fractionation. Four steps sequential extraction of inorganic P from sediments with different solid concentrations (0.1 g/50 mL and 0.2 g/50 mL) were done. The results showed that: the highest content in sediment is HCl-P, followed by BD-P and OH-P, and the least is loosely-P; the P components content decreased by the increased solid concentration, which confirmed solid concentration effect have influences on the processes of sediments inorganic P fractionation; the degree of impact of solid concentration effect on different P components is not equivalent. Strong acids or alkali can effectively inhibit this impact, but cannot counteract it thoroughly.

Osmotic Membrane Bioreactor for Oily Wastewater Treatment using External & Internal Configurations

The present work aims to study the treatment of oily wastewater by means of forward osmosis membrane bioreactor process. Side stream (external) configuration and submerged (internal) configuration of osmotic membrane bioreactor were performed and investigated. The experimental work for each configuration was carried out continuously over 21 days. The flux behavior of forward osmosis membrane in an osmotic membrane bioreactor (OMBR) was investigated, using NaCl as the draw solution and CTA as FO membrane. The effect of mixed liquor suspended solids (MLSS) concentration and TDS accumulation of bioreactor on water flux and membrane fouling behaviors was detected. The accumulation and rejection of nutrients in the bioreactor (Nitrate, COD, and Phosphate) were investigated over the days of the experiment. Water flux and membrane fouling were not significantly affected by MLSS concentration at low level and this effect increase with increasing MLSS concentration (4000–10000 mg/L). Besides, water flux was severely affected by elevated salinity of the aeration tank. OMBR showed high removal of COD (96%) and FO membrane revealed high retention of phosphate (97%) but retention for nitrate was relatively low (72%). The sparingly soluble salts in the influent, bioreactor, draw solution, and RO effluent were detected through the experiment. The results showed flux decline with time to about 47% from the initial flux and two osmotic backwashing were applied at day 7 and 14 during the operation and the flux restored approximately 30% of its loss. Side stream and submerged configurations revealed nearly similar response over the experiments while side stream module showed better water flux (7.0 LMH) than submerged (6.1 LMH). The results showed that the concentration of inorganic ions is below the limits that may cause severe scaling.

Pressure filtration: Bench-scale evaluation and modeling using multivariable regression and Artificial Neural Network

Pressure filtration offers the opportunity to produce solids (filter cake) that can be stacked or mixed with the coarse refuse, and water (filtrate) that can be recirculated in the plant. In this study, the bench-scale pressure filtration testing was performed to dewater coal refuse slurry, which was obtained from the thickener underflow stream of a coal preparation plant, and was being discharged into a slurry impoundment. A flexible fractional factorial design was developed to determine the effects of pressure, pH, and solids concentration on the performance of filtration, which was measured in terms of filtrate flux. The results indicated that the pH had a maximum effect on the filtrate flux followed by the pressure and solids concentration. Additionally, a linear regression model and an Artificial Neural Network (ANN) model were developed to predict the filtrate flux based on the test variables. Both models were able to fit the data well, with R2 values of 0.986 and 0.991 for the linear regression model and the ANN model respectively. It was also found that the test dataset had a mean squared error of 0.2 for the ANN model, while it was 3.99 for the regression model.

Bioleaching combined brine leaching of heavy metals from lead-zinc mine tailings: Transformations during the leaching process

During the process of bioleaching, lead (Pb) recovery is low. This low recovery is caused by a problem with the bioleaching technique. This research investigated the bioleaching combination of bioleaching with brine leaching to remove heavy metals from lead-zinc mine tailings. The impact of different parameters were studied, including the effects of initial pH (1.5–3.0) and solid concentration (5–20%) for bioleaching, and the effects of sodium chloride (NaCl) concentration (10–200 g/L) and temperature (25 and 50 °C) for brine leaching. Complementary characterization experiments (Sequential extraction, X-ray diffractometer (XRD), scanning electronic microscope (SEM)) were also conducted to explore the transformation of tailings during the leaching process. The results showed that bioleaching efficiency was significantly influenced by initial pH and solid concentration. Approximately 85.45% of iron (Fe), 4.12% of Pb, and 97.85% of zinc (Zn) were recovered through bioleaching in optimum conditions. Increasing the brine concentration and temperature promoted lead recovery. Lead was recovered from the bioleaching residues at a rate of 94.70% at 25 °C and at a rate of 99.46% at 50 °C when the NaCl concentration was 150 g/L. The study showed that bioleaching significantly changed the speciation of heavy metals and the formation and surface morphology of tailings. The metals were mainly bound in stable fractions after bioleaching.

The effect of total solids concentration and temperature on biogas production by anaerobic digestion

ABSTRACTThis paper analyzed the effect of total solids (TS) concentration and temperature on biogas production from anaerobic digestion with dairy manure. Batch experiments were carried out for TS concentrations of 6%, 8%, and 10%, respectively, at five different temperatures (31, 34, 37, 40, and 43°C). Results showed that two factors both had significant effect on biogas production. The optimal condition for anaerobic digestion was 8% TS concentration at the temperature of 40°C. Under such condition, the biogas production is much better than the others and the yield peaked higher. Daily biogas production of 8% was more than those test groups which are 6% and 10% under the same temperature. When TS concentration was 8%, the rank of total biogas production of different digestion temperature test was 40 ＞ 37 ＞ 34 ＞ 43 ＞ 31°C, the biogas production of the 31, 34, 37, 40, and 43°C was 0.123, 0.159, 0.171, 0.205, and 0.153 L/g, respectively.

Impact of electro-activation on antioxidant properties of defatted whey

Antioxidant activity of electro-activated whey (EA-whey) was investigated. The effects of electric current intensity (400, 500 or 600 mA) and whey total solids concentration (7, 14 or 21%, w/v) as a function of reaction time (0, 15, 30 or 45 min) on antioxidant properties of defatted whey were studied. The extent of current intensity and reaction times were the most significant parameters (P < 0.001). Oxygen radical absorbance capacity and 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radical scavenging activities of the EA-whey were significantly increased by the formation of Maillard reaction products (MRPs). Moreover, EA-whey possessed reducing power and strong Fe2+ chelating ability. The MRPs derived from the EA-whey with 14% total solids concentration had the highest hydroxyl radical scavenging activity. The findings indicate the potential of electro-activation technology to enhance the functional proprieties of whey; EA-whey could be used in the food industry as a natural antioxidant ingredient to replace synthetic antioxidants.

The effect of spray-drying parameters on the flavor of nonfat dry milk and milk protein concentrate 70.

Unit operations during production influence the sensory properties of nonfat dry milk (NFDM) and milk protein concentrate (MPC). Off-flavors in dried dairy ingredients decrease consumer acceptance of ingredient applications. Previous work has shown that spray-drying parameters affect physical and sensory properties of whole milk powder and whey protein concentrate. The objective of this study was to determine the effect of inlet temperature and feed solids concentration on the flavor of NFDM and MPC 70% (MPC70). Condensed skim milk (50% solids) and condensed liquid MPC70 (32% solids) were produced using pilot-scale dairy processing equipment. The condensed products were then spray dried at either 160, 210, or 260°C inlet temperature and 30, 40, or 50% total solids for NFDM and 12, 22, or 32% for MPC70 in a randomized order. The entire experiment was replicated 3 times. Flavor of the NFDM and MPC70 was evaluated by sensory and instrumental volatile compound analyses. Surface free fat, particle size, and furosine were also analyzed. Both main effects (30, 40, and 50% solids and 160, 210, and 260°C inlet temperature) and interactions between solids concentration and inlet temperature were investigated. Interactions were not significant. In general, results were consistent for NFDM and MPC70. Increasing inlet temperature and feed solids concentration increased sweet aromatic flavor and decreased cardboard flavor and associated lipid oxidation products. Increases in furosine with increased inlet temperature and solids concentration indicated increased Maillard reactions during drying. Particle size increased and surface free fat decreased with increasing inlet temperature and solids concentration. These results demonstrate that increasing inlet temperatures and solids concentration during spray drying decrease off-flavor intensities in NFDM and MPC70 even though the heat treatment is greater compared with low temperature and low solids.

Effect of High Total Solids Concentration on Biogas Production from Cattle Dung

Effect of High Total Solids Concentration on Biogas Production from Cattle Dung

Time-dependent rheological behaviour of cemented backfill mixture

When cemented backfill mixture (CBM) is transported through pipelines from a backfill plant to stopes, it experiences shearing forces over the transport time. In this paper, the effects of solids concentration, binder content, shear rate and curing time on the time-dependent rheological behaviour of CBM were studied. It was found that over long periods of shearing at a constant rate greater than 5 s−1, the shear stress decreased at first and then increased gradually with time. When the shear rate was less than 0.5 s−1, shear stress increased slightly firstly with shearing time, then it started to behave similar to the test with a higher shear rate whose shear stress decreased firstly and then increased. The samples that were sheared at a higher shear rate exhibited a lower apparent viscosity and the higher yield stress CBM samples displayed more pronounced shear-thinning properties. It was also found that for transient flow, increasing the solids concentration and the curing time lead to both a higher initial shear stress (τ0) and minimum shear stress (τmin). When the cement to tailings ratio increased, the τ0, τmin and final shear stress after shearing for 3600 s (τ3600) increased at first, and then subsequently decreased. Moreover, changes in the solids concentration profile and the cement hydration property were displayed during the rheological tests.

Rheological characteristics of mixed kaolin–sand slurry, impacts of pH, temperature, solid concentration and kaolin–sand mixing ratio

Significant amount of slurry waste is produced from mineral processing plants globally constituting high levels of both kaolin and sand in aqueous suspension. Large quantities of slurry and mine tailings require efficient handling, transportation and storage system. The transportation and treatment of kaolin–sand slurry is dependent on its rheological behaviour which is a function of temperature, total solid concentration and pH. In this study, the effects of total solid concentration, pH and temperature on rheological behaviour of kaolin–sand mixture were investigated. These parameters were varied to analyse the viscosity, yield stress, flow index and shear force requirements of the mixed kaolin–sand suspension as a function of these varying parameters. Experimental rheological investigation conducted on rotational stress-controlled rheometer equipped with Peltier concentric cylinder system showed that the kaolin–sand mixture suspension is shear thickening in nature. The shear stress-rate rheograms for the kaolin–sand suspension can be modelled by the Herschel–Bulkley model with high levels of accuracy for pH range of 4–11, temperature range of 20–50 °C and solid concentration of 5–50 %. Solid concentration of the suspension was found to significantly affect the rheological behaviour of the mixture where higher kaolin–sand slurry concentration resulted in greater viscosity and the trend becoming less predictable for solid concentration greater than 50 % by weight. pH was another factor affecting the rheological behaviour of kaolin–sand slurry. pH of 3 or less resulted in the dramatic increase of viscosity of the suspension possibly due to the isoelectric point of the mixture system found between pH of 3 and 4.

The effect of temperature and solid concentration on dynamic viscosity of MWCNT/MgO (20–80)–SAE50 hybrid nano-lubricant and proposing a new correlation: An experimental study

The main objective of the present paper is to investigate the dynamic viscosity of MWCNT/MgO (20–80)–SAE50 hybrid nano-lubricant. The experiments carried out in solid concentrations ranging from 0.25% to 2% and temperatures ranging from 25°C to 50°C. The results revealed that the nano-lubricant shows Newtonian behavior in all the studied temperatures and solid concentrations. Furthermore, the experimental results showed that the dynamic viscosity decreased as the temperature increased. It is also revealed that increasing the solid concentration leads to increasing the dynamic viscosity of the nano-lubricant in all the temperatures. The maximum increase in dynamic viscosity took place at the solid concentration of 2% and temperature of 40°C by 65% while the minimum increase was at the solid concentration of 0.25% and temperature of 25°C by 14.4%. Finally, applying curve fitting method on the experimental data, a new model to predict the dynamic viscosity of the studied nano-lubricant in terms of temperature and solid concentration has been proposed.

The fouling behavior in microfiltration of activated sludge suspension from submerged membrane bioreactors (SBR)—The boundary flux and sub boundary fouling rate index

The boundary flux (Jb) and sub boundary fouling rate index (α) in constant pressure microfiltration of activated sludge suspension from SBR were determined using TMP-step method. Effects of mixed liquor suspended solids concentration (MLSS), stirring rate and the mean pore size of the membrane on Jb and α were also analyzed using the factorial experiment method. Results showed that the influence sequence of operating conditions on Jb was as follows: mean pore size of the membrane > stirring rate > MLSS concentration. Specially, the effect of shifting mean membrane pore size from 0.01 µm to 0.1 µm or from 0.01 µm to 0.22 µm on Jb was almost six times or twice as much as that of increasing stirring rate from 100 rpm to 300 rpm in the tested MLSS concentration range. The fact that the membrane with lager pore size was easy to be internally fouled at the initial filtration period was confirmed by analyzing α and morphologies of fouled membranes.

The Effect of Processing Parameters and Solid Concentration on the Microstructure and Pore Architecture of Gelatin-Chitosan Scaffolds Produced by Freeze-Drying

One of the main components for being successful in tissue engineering is developing a scaffold with an appropriate architecture for allow migration, cell proliferation, and differentiation. A gelatin-chitosan scaffold by vacuum freeze-drying has been developed for tissue engineering applications. The effects of solid concentration and freezing processing on the scaffold morphology and porous size were investigated. As the chitosan content was increased the viscoelastic properties of pigskin gelatin was modified, the maximum G' values were lower than the values for pure gelatin solution, and the thermal transition points also occurred at lower temperatures, as well as a decrease of pore size tendency was observed and the scaffold visibly increased porosity, the structure scaffold was observed with an interconnected and more homogeneous pore matrix. The pore sizes become smaller and pore walls thinner, while interconnectivity increases along with declining pre-freezing temperature. The chitosan-gelatin scaffold will be a promising candidate in tissue engineering.

Inputs and seasonal removal of pharmaceuticals in the estuarine Garonne River

Pharmaceuticals were screened in the estuarine Garonne River to investigate the role of estuaries as passive or active transfer compartments in the removal of these compounds. Monthly monitoring of 53 pharmaceuticals from various therapeutic classes at 6 sampling points over 18months showed that most compounds were frequently detected with median concentrations in the low ngL−1 range. Saline intrusion was responsible of an overall dilution but an enrichment from the treated urban effluents of Bordeaux city was also observed with increases resulting from this input being compound dependent. An average cumulated load of 10kg of the monitored pharmaceuticals was found to enter the estuary daily from the catchment area. After normalization to the persistent marker carbamazepine, a large majority of the compounds were found to exhibit in-stream attenuation during summer while this removal was enhanced farther down the estuary, indicating a likely effect of residence time, temperature and suspended solid concentration on the stability of the pharmaceuticals.

Experimental and numerical investigations of scale-up effects on the hydrodynamics of slurry bubble columns

Experiments and simulations were conducted for bubble columns with diameter of 0.2m (180mm i.d.), 0.5m (476mm i.d.) and 0.8m (760mm i.d.) at high superficial gas velocities (0.12–0.62m·s−1) and high solid concentrations (0–30vol%). Radial profiles of time-averaged gas holdup, axial liquid velocity, and turbulent kinetic energy were measured by using in-house developed conductivity probes and Pavlov tubes. Effects of column diameter, superficial gas velocity, and solid concentration were investigated in a wide range of operating conditions. Experimental results indicated that the average gas holdup remarkably increases with superficial gas velocity, and the radial profiles of investigated flow properties become steeper at high superficial gas velocities. The axial liquid velocities significantly increase with the growth of the column size, whereas the gas holdup was slightly affected. The presence of solid in bubble columns would inhibit the breakage of bubbles, which results in an increase in bubble rise velocity and a decrease in gas holdup, but time-averaged axial liquid velocities remain almost the same as that of the hollow column. Furthermore, a 2-D axisymmetric k–ε model was used to simulate heterogeneous bubbly flow using commercial code FLUENT 6.2. The lateral lift force and the turbulent diffusion force were introduced for the determination of gas holdup profiles and the effects of solid concentration were considered as the variation of average bubble diameter in the model. Results predicted by the CFD simulation showed good agreement with experimental data.

Dynamic viscosity of MWCNT/ZnO–engine oil hybrid nanofluid: An experimental investigation and new correlation in different temperatures and solid concentrations

The major objective of the present study was to investigate the dynamic viscosity of MWCNT/ZnO–engine oil hybrid nanofluid. The experiments carried out in different temperatures ranging from 5°C to 55°C and solid concentrations ranging from, 0.125% to 1%. The viscosity of the MWCNT/ZnO nanoparticle with the mean diameter of 30nm dispersed in engine oil was measured using Brookfield cone and plate viscometer. The effect of temperature and solid concentration on dynamic viscosity of the nanofluid has been experimentally investigated. The results indicated that increasing the temperature resulted in decreasing the dynamic viscosity of the nanofluid by 85% while the dynamic viscosity increased as the solid concentration increased by 45%. Furthermore, based on the experimental data, a new model to predict the dynamic viscosity of the studied nanofluid has been proposed.

Effects of Temperature, Polymer Dose, and Solid Concentration on the Rheological Characteristics and Dewaterability of Digested Sludge of Wastewater Treatment Plant (WWTP)

The rheology of digested sludge affects the flow hydrodynamics, dewaterability, and the polymer consumption in wastewater treatment plants. The rheological characteristics of digested sludge are highly dependent on changes in total solid concentration, temperature, and polymer dose. Hence, this study aims at investigating the impacts of total solid concentration, temperature, and polymer dose on the rheological characteristics and the dewaterability of digested sludge. Investigating the relationship between rheological and physicochemical characteristics of sludge can also serve as a tool to optimize essential process parameters. Different homogenized digested sludge samples were subjected to rheological measurement on rotational stress-controlled rheometer equipped with Peltier concentric cylinder system. The shear stress–shear rate and viscosity–shear rate curves were then developed before and after polymer conditioning at various temperatures and solid concentrations. Different rheological model were fitted to the shear stress–shear rate and viscosity–shear rate rheograms, and the model with the best fitting and more practical significance was selected to determine key rheological parameters. The relationship between dewaterability and digested sludge rheology was also developed. The rheological characteristics of digested sludge during polymer conditioning and flocculation process was significantly affected by temperature and solid concentration; hence, polymer dose can be reduced by operating the dewatering process at optimum temperature condition and varying the polydose as a function of the total solid concentration and viscosity of the digested sludge. The dewaterability as measured in capillary suction time (CST) improved with increasing polymer dose up to 12 kg/t DS but further increase in polymer dose resulted in the deterioration of the dewaterability due to overdosing.

Adsorption of Arsenic (V) to Titanium Dioxide Nanoparticles: Effect of Particle Size, Solid Concentration, and Other Metals

Abstract Adsorption of arsenate on titanium dioxide nanoparticles and bulk particles was studied at pH 4.5 and 7. Nanoparticle and bulk particle concentrations were 0.1–0.5 and 0.5–1.0 g/L, respectively. Initial Arsenic (As) (V) concentration ranged from 40 to 3,100 μg/L. Nanoparticles adsorbed more As (V) when normalized by mass, and bulk particles adsorbed more As (V) when normalized by surface area. At the same initial As (V) concentration, more As (V) was adsorbed at pH 4.5 than at pH 7. Adsorption data were best fitted with Freundlich isotherm model with r2 ranging from 0.97 to 0.99. Kinetic study showed that pseudo-second order model best describes the adsorption rate with r2 > 0.99. Simultaneous adsorption of single (As) and multiple metals (Zn, Cd, Pb) in San Antonio tap water was studied. Presence of multiple metals did not compete for As (V) adsorption sites in San Antonio tap water. The kinetic study showed an increased adsorption rate of As (V) in the presence of coexisting metals. Comparison ...

Maximizing gas–liquid interfacial area in a three-phase stirred vessel operating at high solids concentrations

The present work focuses on the determination of gas holdup, Sauter mean bubble diameter (d32) and gas–liquid interfacial area (αg−l) for radial- and mixed-flow impellers under various operating conditions in a three-phase stirred vessel. d32 values were determined for a wide range of solids concentration (0.01–0.25v/v) using an underwater imaging technique when particles are just suspended off the tank bottom. The results indicated that d32 values decrease with an increase in particle size and solids concentration at a constant gas flow rate. It was observed that process intensification is an effective strategy for improving the interfacial area between the gas and liquid phases in a multi-phase stirred tank agitated by a radial-flow impeller. Considering the effect of solids concentration on impeller specific power, an optimum solids concentration is identified at which the performance of the impeller expressed in terms of power efficiency and ability to generate sufficient gas–liquid interfacial area is maximized. Mathematical correlations to estimate d32 and αg−l in gas–liquid–solid stirred vessels are proposed.

CFD simulations of direct contact volumetric heat transfer coefficient in a slurry bubble column at a high gas temperature of a helium–water–alumina system

In this paper, computational fluid dynamics (CFD) simulations are used to investigate the volumetric heat transfer coefficient in a direct contact heat transfer for a helium–water–alumina slurry bubble column reactor, where helium gas is injected at 90 °C through a slurry of water at 22 °C and alumina solid particles. This paper studies the effects of superficial gas velocity, static liquid height, and solid particle concentration on the volumetric heat transfer coefficient of the slurry bubble column reactor. In this study, it is assumed that the slurry inside the slurry bubble column is perfectly mixed, and the approach used to model the slurry bubble column by CFD is 2D plane. From the CFD results, it is found that the volumetric heat transfer coefficient increases by increasing the superficial gas velocity and decreases by increasing the static liquid height and/or the solid concentration at any given superficial gas velocity. Also, it is found that the rate of decrease of the volumetric heat transfer coefficient with the solid concentration is approximately the same for different superficial gas velocities. The results of CFD simulations were compared with experimental data from previous literature and show that the profiles of the volumetric heat transfer coefficient calculated from CFD models generally under-predict the experimental data. The CFD model correctly predicts the experimental effects of static liquid height and solid concentration on volumetric heat transfer coefficient.