Slurry Concentration Research Articles

Rheological characteristics of bauxite slurry with varying concentration, particle size distribution, and modal distribution for pipeline transportation

Some of the foremost parameters effecting the slurry rheology, preferably the slurry concentration, particle size distribution, and modal distributions, were studied in the current findings, figuring out the variation in shear stress and apparent viscosity using a rotational rheometer. The particle size considered for the test ranges from fine particle size of −75 µm to coarse particle size of +75–300 µm, separated at varied size fractions of +75–105, +105–150, +150–210, and +210–300 µm. The −75 µm bauxite slurry at 60 wt% has shown a maximum static settled concentration (Cw -max) under gravity after 48 h free settlement. This fine particle slurry at varying concentrations of Cw = 45–65% is discerned to behave like a Non-Newtonian Bingham plastic fluid at lower concentrations, unlike the other coarse fraction bauxite slurries at Cw = 55%, which exhibit shear thickening behavior. The present work carried out adds knowledge on the rheological behavior of bimodal, trimodal, and multimodal with four and five different size fraction bauxite slurries in finding the optimum mass concentration for a particle size fraction of (coarse):(fine), obtained in the ratio (25):(75), (25:25):(50), (25:25:10):(40), and (15:15:15:15):(40), respectively of the total 60 wt%. Certain parameters, like yield stress, consistency index (k), and flow behavior index (n), were estimated upon fitting the modal distributions to the Herschel Bulkley model to choose the best particle size distribution of the bauxite sample showing improved slurry stability, rheology, and flow characteristics.

Concentrated biogas slurry and biogas residue can improve the yield and quality of pepper.

The organic fertilizer (biogas slurry and biogas residues) was produced by the self-developed integrated device of "Pressure swirl / inclined plate sedimentation separation pretreatment (P/I) combined with ultrafiltration / reverse osmosis two stages membrane separation (UF/RO)". The paper focuses on the effect of concentrated biogas slurry and biogas residue produced by this technology on the yield and quality (vitamin C, soluble sugar, protein and nitrate content) of pepper as organic fertilizer compared with chemical fertilizer. The concentrated biogas slurry and biogas residue separated by this technology contained active substances such as N, P, K, trace elements and humic acids with stable composition and potential for good fertilization efficiency. The experiment of seed soaking for pepper sprouting confirmed the best effect of seed soaking with a concentration of 80% biogas slurry. Compared with chemical fertilizer treatment, the application of concentrated biogas slurry and biogas residue can improve the yield and quality of pepper, which is related to the nutrient elements in concentrated digestate. Meanwhile, the results of pepper cultivation trials show that the base fertilizer treatment of biogas residue is best with 2000kg/667m2 and foliar spraying of 75% biogas slurry. The results strongly demonstrate the great potential of the concentrated biogas slurry and biogas residue produced by the self-developed digestate concentration technology for pepper cultivation.

Modified ganyong (Canna edulis Kerr.) starch prospective as wheat flour alternative

Ganyong tuber (Canna edulis Kerr.) had high carbohydrate content and has potential to be used as starch. However, the starch obtained was low quality, characterized by brownish color and limited functional properties. The main aim of this work was to obtained the optimum process to transform canna starch into commercial wheat flour SNI 3751:2009 by oxidizing with food grade hydrogen peroxide (H2O2). The raw material used was white canna tuber from Samarinda, East Kalimatan which have high carbohydrate content. Initially, the starch was oxidized by 35% H2O2 food grade to form 1%, 2%, 3% concentration, slurry ratio of 10%, 20%, 30% and time of oxidation was 30, 60, 90 and 120 mins. The ganyong tuber starch was then subjected to modification process by optimizing the slurry ratio and H2O2 oxidation time. The assessment was based on basic functional properties, swelling power and water solubility. The process was conducted using a mini-propeller chamber, and data were collected in triplicates for accuracy. The optimum result was achieved with a 60-min oxidation time, 10% slurry concentration and 2% H2O2 concentration. The swelling power value reached 2.9 g/g, and water solubility was measured at 6.09 g/g. Upon proximate analysis, the canna starch contained 85.956% carbohydrates, 2.365% protein, 11.425% water and 0.254% ash content. The color analysis indicated a white degree with brightness of 91.95. Despite the improvements achieved through the process, the functional and other properties of ganyong starch were still considerably below of wheat flour standard.

Online analysis of iron ore slurry using PGNAA technology with artificial neural network

Real-time analysis of metallic mineral grade and slurry concentration is significant for improving flotation efficiency and product quality. This study proposes an online detection method of ore slurry combining the Prompt Gamma Neutron Activation Analysis (PGNAA) technology and artificial neural network (ANN), which can provide mineral information rapidly and accurately. Firstly, a PGNAA analyzer based on a D-T neutron generator and a BGO detector was used to obtain a gamma-ray spectrum dataset of ore slurry samples, which was used to construct and optimize the ANN model for adaptive analysis. The evaluation metrics calculated by leave-one-out cross-validation indicated that, compared with the weighted library least squares (WLLS) approach, ANN obtained more precise and stable results, with mean absolute percentage errors of 4.66% and 2.80% for Fe grade and slurry concentration, respectively, and the highest average standard deviation of only 0.0119. Meanwhile, the analytical errors of the samples most affected by matrix effects was reduced to 0.61 times and 0.56 times of the WLLS method, respectively.

3D printing of high solid Al2O3 ceramics based on green and renewable photosensitive resin with low viscosity and low shrinkage

AbstractA low‐viscosity bio‐based carbamate acrylate was synthesized by the reaction of pentamethylene diisocyanate derived from pentanediamine with a low molecular weight acrylate hydroxyl ester. The carbamate acrylate was used in the 3D printing of ceramics, and a correlation between the solid content and viscosity of the ceramic slurry was observed. The ceramic slurry exhibits good stability and low shrinkage. The results indicate that the viscosity of the ceramic slurry was 2.11 Pa s with a solid content of 80 wt%, which makes it suitable for digital light processing printing. In addition, a new type of photoinitiator called (2,4,6‐trimethylbenzoyl)bis(p‐tolyl)phosphine oxide (TMO) has been applied, demonstrating excellent potential in ceramic slurry. According to its thermogravimetric curve, a debinding and sintering process was designed, and ultimately an Al2O3 device with a density of 94.49% was prepared.

Enhanced leaching of copper from refractory oxidized copper ore by calcium fluoride: Behavior and mechanism

The Luanshya area of Zambia is rich in copper oxide resources. However, copper mainly exists in biotite and phlogopite, which presents challenges for efficient extraction. To improve the leaching rate of copper from these ores, local hydrometallurgical plants use heating and stirring; however, the leaching rate is not high. To address the issue in this work, CaF2 was introduced as a leaching aid, and the effects of various parameters on leaching were systematically studied. The results revealed that when the dosage of CaF2 is 5wt% of raw ore mass, the dosage of sulfuric acid is 120 kg/t, the leaching temperature is 60 °C, and the leaching time is 200 min with a slurry concentration of 30wt%, the leaching rate of copper can reach 80.44%. Compared with regular heating stirring acid leaching, the copper leaching rate was found to increase by 8.76%, while the leaching temperature decreased by 5 °C and the leaching time shortened by 40 min. The results of the HSC Chemistry 6.0 thermodynamic calculations and mechanism analysis indicated that F can promote the fracture of Si–O and Al–O bonds in the crystal structure of biotite and phlogopite in sulfuric acid solution, enabling a direct reaction between the acid and copper. The proposed method can be applied not only to the treatment of cupriferous mica ores but also to the processing of other copper ores. This process is more efficient and cost-effective than the regular heating–stirring acid leaching process.

Optimization of specific energy consumption in the high concentration slurry disposal pipelines for coal ash in thermal power plants

ABSTRACT In thermal power plants, the disposal of coal fly ash is one of the major challenges requiring energy input for its safe disposal, so optimization is needed to minimize the required energy input at maximum fly ash transportation. Present work is focussed on high concentration optimized transportation of ash slurry in thermal power plants using Computational Fluid Dynamics (CFD) which behaves as a Bingham plastic fluid, modeled using Herschel-Bulkley model. Specific Energy Consumption (SEC) is the measure of the energy required for the slurry transportation. Therefore, a parametric investigation to establish the effect of concentration of slurry (Cw), pipe diameter (D), no. of pipes (N), particle size (d) over SEC is conducted. Therefore, these operational parameters need to be carefully selected, as even a minor variation from the desired optimum values may result in huge SEC consumption thereby causing financial consequences. It is found in the current study that the SEC substantially depends on all of the above-mentioned parameters. Mathematical models for prediction of SEC based on the study are also developed for the future designers of such systems.

Drum drying of whole maize flour enhances bioaccessibility of zeaxanthin, α-tocopherol, phytosterols, phenolics and flavonoids

The aim of the present study was to investigate the effect of drum drying of maize flour at slurry concentration of 30%–40% on phytonutrients content and their bioaccessibility. Content of tocopherols (TP), tocotrienol (TT), carotenoids, phytosterols, polyphenols and flavonoids, and antioxidant activity in drum dried maize was decreased. Bioaccessible content of stigmasterol, β-sitosterol and flavonoids was increased in drum dried maize. Bioaccessible content of campesterol and total phenolics was comparable to the bioaccessible content in raw maize. Bioaccessible content of TP, TT, lutein, zeaxanthin and β-carotene decreased in drum dried samples. DPPH + radical scavenging activity of bioaccessible fraction of drum dried maize was increased. The ferric reducing power was stable and total antioxidant activity decreased in bioaccessible fraction of drum dried sample. Percentage bioaccessibility of α-TP, phytosterols, zeaxanthin, phenolics, flavonoids and antioxidant activity was increased. Bioaccessibility of lutein and β-carotene retained, and γ-TP, δ-TP, α-, γ-, δ-TT decreased in drum dried sample. Overall, phytonutrients content was found to be low in drum dried samples, but there was retention of components in bioaccessible fraction which resulted higher percentage bioaccessibility of maize phytonutrients.

Alkaline pulping catalyzed ordered conversion of bark in supercritical water

The hydrophilicity of lignocellulosic biomass hinders the application of a high concentration slurry for supercritical water gasification, thereby reducing the gasification efficiency and energy self-sufficiency. A pretreatment method of alkaline pulping with KOH and NaOH was proposed to achieve the high feed concentration for continuous reactor and macromolecular simplification for barrier reduction of conversion. In this study, bark as an example of lignocellulosic biomass, whose 30 wt% and 40 wt% slurries with favorable rheology and stability, was prepared by alkaline pulping successfully. The minimum alkali consumption of NaOH and KOH pulping for 30 wt% and 40 wt% were 11%–14%, 16%–20%, and 16%–21%, 23%–28%, respectively. The most economical conditions were 180 °C and 24% KOH addition. All slurries prepared by NaOH and KOH at 180 and 200 °C could satisfy the industrial standard of coal-water slurry, and only 3–5 times higher than water viscosity. The bark macromolecules were restructured due to the hydrolysis of cellulose and lignin by breaking down the hydrogen bond and ether bond with trivial hydrocarbon matrix loss. The scattered crystal growth facilitated the uniform premixing of bark and water. Meanwhile, a surface particle charges potential increase leading to a heightened repulsive force by alkaline pulping furtherly enhanced the premixing effect. Additionally, metal ions could be deposited onto the bark surface during alkaline pulping. The chemical modification leading by alkaline pulping achieved the premixing of feedstock and water to form bark slurry. The conversion barrier was decreased to fulfill the ordered conversion, and 95.66% gasification efficiency for 40 wt% bark slurry was displayed at 600 °C with a preheated water of 6. Phenolic compounds and hydrocarbons were the most dominant components in liquid products. Polycyclic aromatic hydrocarbons in liquid products were detected at 620 °C with a preheated water of 4. The functional groups of organic matter in the slurry were significantly converted into the gas phase, and lattice oxygen was produced in the solid product. The alkali recovery was 65% at the optimal gasification condition, and achieved the maximum of 80% at 580 °C. The successful completion of this research affirms the dominance of the pulping-alkali recovery-gasification method for expanding the application of SCWG of lignocellulosic biomass in large engineering projects.

Influence of particle size gradation on the preparation of highly concentrated coal-water slurry and the development of a gradation model

ABSTRACT Aiming at the problem that low-rank coal is unsuitable for making CWS (coal-water slurry) and lacks an accurate particle size gradation prediction model. This paper expounds on the effects of ball milling time and speed on the concentration and rheology of CWS under different grinding conditions. After size grading, the slurry’s bimodal parameters and particle size distribution are studied. Based on the BP neural network, a particle size distribution model more suitable for low-rank coal is established in this paper. The results show that the slurry concentration in the graded coal sample increases by 4% higher than that of the ungraded coal sample. The BP neural network model accurately predicts the relationship between bimodal parameters and slurry concentration based on bimodal parameters. In the context of grain size gradation, the optimized particle size cumulative distribution model, denoted as y = x n − x K n x 100 n − x K n + K { ( K + 10 % > x > K% } , demonstrates enhanced alignment with the attributes of low-rank coal. This underscores the paper’s contribution in providing a more fitting particle size distribution model for low-rank coal in the context of CWS production.

Investigation of the effect of the surfactant on the mixing of highly concentrated slurries of fine particles via SEM, RSM, and CFD

The main purpose of this research was to explore the likelihood of preparation of highly concentrated slurries of stabilized submicron CaCO3 particles using a surfactant in a pilot-scale mixing system. To achieve this goal, the effects of independent factors such as CaCO3 and surfactant (lecithin) concentrations, impeller type, and their interactions on power consumption, slurry rheological characteristics, and particle size were investigated. Employing the Eulerian-Granular multiphase model, a computational fluid dynamics model (CFD) was created. The validated CFD model was utilized to assess the degree of homogeneity for slurries agitated inside the mixing system. The lowest power consumption, the smallest particle size and consistency index, and the highest power-law index were achieved for highly concentrated slurries containing the optimal amount of lecithin (3.5 wt%) for the stabilization of fine CaCO3 particles. The high-shear sawtooth impeller was shown to be the most efficient impeller for mixing fine CaCO3 slurries containing lecithin.

How does mine tailings slurry solids concentration affect stability of dam embankment slope?

ABSTRACT In view of many past failures of tailings storage facilities, practising engineers have been analysing current design guidelines for different elements of these facilities, including for tailings dams. In this paper, an attempt is made to investigate how varying tailings slurry solids concentration ( c s ) affects the stability of tailings dam embankment slope. To achieve this, elaborate two-dimensional limit equilibrium and finite element simulations were conducted and a steady-state seepage analysis was performed so as to obtain accurate free surface water flux through the slope. Initially, numerical analyses were performed for the downstream embankment slope when no material is retained upstream. Subsequently, with all parameters kept constant, the same slope was then checked when water is retained upstream, and finally for varying slurry solids concentration. Special attention was paid to the boundary between sedimentation and consolidation, defined as the solids concentration limit beyond which effective stresses start to develop. From the stability analyses performed, it is found that the factor of safety of embankment slope varies nonlinearly with total unit weight of the slurry. For coal tailings slurry, factor of safety reduced from 1.24 when water is retained to 1.15 when tailings slurry with c w = 60% is retained, representing a drop by 7.3%.

Slurry erosion behaviour of AlCoCrFeNi high entropy alloy coating prepared by atmospheric plasma spraying

ABSTRACT This study explores the application of AlCoCrFeNi high entropy alloy (HEA) coating on the SS316L steel using atmospheric plasma spraying to enhance durability in erosive environments. Annealing the coated sample at 650°C resulted in a uniform, dense coating with homogeneous HEA distribution, exhibiting a 16.2% improvement in microhardness compared to the pre-annealed coating. Slurry jet erosion testing revealed that under specific conditions (10 m s−1 impact velocity, 90° impingement angle and 10 wt-% slurry concentration), the annealed coating demonstrated a lower erosion rate. Increased velocity correlated with higher erosion rates due to augmented material removal, while normal angles exhibited lower erosion rates than oblique angles, emphasising plastic deformation over material removal. Initial erosion rate increases with slurry concentration were observed, followed by a decrease due to the protective effect of a slurry cloud at higher concentrations. Overall, the HEA-coated layer effectively safeguarded against erosive wear, particularly post-annealing, because of enhanced hardness.

Experimental study on environmental chemical effect and purification treatment of waste slurry in horizontal directional drilling

The waste slurry generated during Horizontal Directional Drilling (HDD) has detrimental effects on water sources, soil, and organisms. Existing studies lack quantitative analysis and assessment of the environmental hazards of waste slurry. The treatment of waste slurry is usually done by physical curing or chemical curing agents. The treatment effect of these treatments is unsatisfactory or not environmentally friendly enough. Research on the application of Microbially Induced Calcite Precipitation (MICP) in waste slurry purification can help provide innovative solutions. This study began by acquiring the basic properties, mineral composition, and particle size distribution of the waste slurry through experiments. The effects of different concentrations of waste slurry on soil chemical properties were compared, including the measurement of total dissolved solids (TDS), turbidity, and heavy metal ion concentrations of waste slurry supernatant. Additionally, the environmental impact of the waste slurry was assessed from an electrochemical, turbidity, and ionic composition perspectively. A combination formulation containing 2.8 wt% urease, 5 wt% urea, and 3.5 wt% calcium chloride was used to purify the waste slurry. The supernatant of the MICP treated waste slurry undergoes electrochemical testing to evaluate the effectiveness of MICP technology for slurry treatment. The findings indicate that both chemical additives and stratum contaminants significantly contribute to slurry pollution. When the waste slurry constitutes more than 40 wt% of the soil mass fraction, the electrical conductivity (EC) of the soil surpasses the threshold of 1000 μs/cm, and the pH level rises to approximately 9.5, rendering it unsuitable for plant growth. Moreover, the TDS, turbidity, and heavy metal ion concentrations in the waste slurry supernatant exceed the permissible environmental discharge limits. Notably, the concentration of arsenic (As) exceeds the national standard by 18 times, cadmium (Cd) by 20 times, and selenium (Se) by 208 times, posing a high risk of environmental pollution. However, the comparison of ion concentrations in the supernatant before and after MICP treatment reveals that MICP demonstrates effective cementation and co-precipitation of heavy metal ions. MICP purified 66.6 % of arsenic (As), all cadmium (Cd), 75 % of phosphorus (P), and 76 % of selenium (Se) from the waste slurry supernatant. The results of this research contribute to the quantitative evaluation of the environmental hazards of waste slurry. It also helps to promote the application of MICP in waste slurry purification.

Strength and leaching behavior of tailing-based paste backfill at high water content amended with lime activated ground granulated blast furnace slag and flocculant.

Flocculent is commonly used in mining activities to improve the concentration of tailing slurry by enhancing the sedimentation process of small tailings particles. The presence of flocculent in thickened tailings is unavoidable, and it affects the heavy metal leaching performances and mechanical and rheological characteristics of tailing-based cemented paste backfill (CPB). This study is carried out to investigate the physicochemical and leachability of CPB amended with flocculants and lime-activated ground granulated blast-furnace slag (GGBS). The stabilized samples were subjected to a series of model tests, including toxicity characteristics leaching procedure (TCLP) and pH, unconfined compressive strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction. Moreover, the CPB amended with anionic polyacrylamide (APAM) demonstrated better performance in terms of a decrease in heavy metal leachability besides higher mechanical strength than poly aluminum chloride (PAC) and poly ferric chloride (PFC) samples. Furthermore, the UCS results showed that increasing binder content up to 15% negatively influences strength improvement of all stabilized samples because of weak connections between soil particles and cementitious material, resulting in high leachability of heavy metals. The analysis of XRD and SEM showed that anionic polyacrylamide (APAM) cases exhibited more voluminous hydration products, resulting in a compact stabilized matrix and substantially reduced heavy metal leachability.

Recovery of Noble Metals (Au, Pt, Ir, and Ta) from Spent Single-Use Medical–Technological Products

Due to their unique properties, i.e., fluoroscopy response and inertness, noble metals and alloys are present in several widespread medical–technological products, such as catheters, guide-wires, and stents. Despite their value, these products serve as single-use consumables, following a fate of solid waste disposal and loss of their valuable metals. This work studies the development of a treatment methodology to recover noble metals such as Pt, Ir, Au, and Ta from certain commercial products commonly used for medical practices. In particular, a sequence of preliminary pyrolysis, aiming at polymer elimination, as well as an acid digestion step for selective metals dissolution, is suggested. Pyrolysis was capable of enriching samples with the targeted metals, though a small change in their oxidation states was observed. Still, acid digestion was fully able to successfully separate Au using a 50% v/v aqua regia solution for 30 min at room temperature and the Pt/Ir using concentrated aqua regia for 72 h under heating. Dissolution of Ta required a different leaching solution, i.e., a 50% v/v HF/H2SO4 mixture for 10 h under heating. According to the developed method, selective extraction of such noble metals in a concentrated slurry provides a high potential for the complete recovery and valorization of otherwise disposed medical wastes.

Experimental In-Situ Observatory on Brownian Motion Behavior of 105 nm Sized Silica Particles During Chemical Mechanical Polishing of 4H-SiC by an Evanescent Field

The experimentally observing optical systems for on-machine measurement have been developed to study on nano-polishing phenomena during the chemical mechanical polishing process, which is a wet process in semiconductor manufacturing. The developed optical system employs an evanescent field to selectively enhance exclusively the observatory of phenomena occurring on the surface being polished, offering a lateral resolving power of approximately 400 nm, in the slurry concentration of up to 5 wt% based on the numerical aperture of the objective lens. In addition, there is also the observability of 105 nm and down to 55 nm-sized silica particles without requiring additive fluorescence agents in or around the nano-particles, even when these particles are moving on surfaces such as silica glass or hard materials (silicon carbide: 4H-SiC). Consequently, the motion behavior of nano-particles disjoining with polishing pad asperity was explored and discussed, in this paper. Experimental results revealed that the polishing pad spatially constrains the movement of particles between the pad and the substrate surface, guiding them toward the surface being polished. During pad sliding, fluidically dragged nano-particles exhibit slower movement than the polishing pad sliding speed while retaining the Brownian motion. Furthermore, 105 nm-sized silica particles did not continuously approach to attach onto the SiC surface; the nano-particles approached in steps with reduced Brownian motion in all directions before attaching. This behavior can be attributed to the effects of van der Waals attraction and electrostatic repulsion forces between the particle and the substrate surfaces.

Evolutionary patterns and microscopic mechanisms of strength in mine tailings backfilled with waste glass

In order to promote the sustainable use of resources and reduce the waste of waste glass and tailings resources. The present study focuses on a fluorite mine as the research subject, utilizing coarse tailings, fine tailings, cement substitute-curing agent, and recycled waste glass as the primary raw materials. It investigates the changes in compressive strength of coarse tailing with varying sand- binder ratios and glass content at 3-day, 7-day, and 28-day intervals when the filling slurry concentration is set at 77% and the ratio of coarse tailings to fine tailings is maintained at 2:1. The findings indicate that there is minimal impact on the compressive strength of test blocks when using a sand binder ratio of 4:1 and a glass sand content below 10%. However, once the glass sand content exceeds 10%, a significant decline in compressive strength occurs. Scanning electron microscope (SEM) images reveal ettringite crystal formation in test blocks with both 0% and 25% glass sand content due to high levels of Na2O in the glass sand. This leads to internal expansion within test blocks resulting in reduced strength. Notably, when using a sand-binder ratio of 8:1 along with a glass sand content of 25%, early strength characteristics are observed for test blocks. Furthermore, incorporating glass sand has little influence on late-stage strength for backfill when employing either an 8:1 or 12:1 sand-binder ratio. Based on this experiment conducted under conditions including mass concentration of 77%, the optimal waste-glass-to-mine-tailings-filling-sand-binder-ratio is determined as 8:1with a corresponding glass content of 25%.

Precision forecasting of spray-dry desulfurization using Gaussian noise data augmentation and k-fold cross-validation optimized neural computing

Perceptron models have become integral tools for pattern recognition and classification problems in engineering fields. This study envisioned implementing artificial neural networks to forecast the performance of a mini-spray dryer for desulfurization activities. This work adopted k-fold cross-validation, a rigorous technique that evaluates model performance across multiple data segments. Several ANN models (21) were trained on data obtained from sulfation conditions, including sulfation temperature (120 °C–200 °C), slurry pH (4–12), stoichiometric ratio (0.5–2.5), slurry solid concentration (6%–14%) as the feed input and sulfur capture as the response. Three hundred synthetic datasets generated using the Gaussian noise data augmentation underwent a 10-fold cross-validation process before simulation on neural networks triggered by the logsig and tansig activation functions. The computation accuracy was further evaluated by altering the number of hidden cells from 2 to 10. The ANN architectures were assessed using statistical metrics such as mean square error (MSE), root mean square error (RMSE), mean absolute percentage error (MAPE), and the coefficient of determination (R 2) techniques. Overall, error estimation suggests cross-validation and data augmentation are critical in efficient neural network generalization. The logsig function trained with 10 hidden cells presented closer data articulation when mapped onto actual values.

Experimental Study on Two-Phase (Solid-Liquid) Flows of Ground Wheat Straw in Inclined Pipes

Highlights Knife milled wheat straw-water slurry flow through inclined pipes at various inclinations is experimentally studied. Slurry concentration and pipe inclination affect the onset velocity of drag reduction and the percentage of drag reduction. The critical mass concentration of maximum drag reduction is a vital function of velocity and is independent of the pipe angle. Downhill wheat straw slurry flows exhibit the most significant reduction in drag and the smallest onset velocities. Wheat straw slurry flows moving uphill exhibit nonmonotonic variations in onset velocity and drag reduction. Abstract. Long-distance pipeline hydro-transport of lignocellulosic biomass for industrial-scale biofuel production at levels comparable to conventional oil refineries presents an economically and logistically viable alternative to fossil fuels. There is very limited understanding on the behavior of the transportation of agricultural biomass slurries in an inclined pipeline. This research is focused on a laboratory-scale investigation of 6.4 mm nominal particle length (d50 = 4.85 mm) knife-milled wheat straw-water suspensions' uphill and downhill flows for a range of pipe inclination and saturated mass concentrations. The range of pipe inclination and saturated mass concentration was -7° to +21° and 5%-30%, respectively. The inclined test section was 29 m long with a 50 mm inside diameter of a closed pipeline loop. The accuracy of the measurements was verified by calibrating the inclined pipe section with fine sand (d50 = 0.103 mm)-aqueous slurries and comparing the results with established correlations. Most wheat straw-aqueous suspensions in the inclined flows showed the characteristics of the plug flow and the transition flow regions together for saturated mass concentration, Cm = 5%-30% and the entire flow range (0.5-4.7 m s-1), with a clear dependence of both the onset velocity of drag reduction (vOD) and drag reduction (%DR) on the pipe inclination as well as the slurry concentration and the critical concentration of maximum drag reduction (Cm)cr on a specific range of suspension velocity. Because of the accelerating effect of gravity, downhill slurry flows had the lowest vOD and the highest %DR at every Cm and pipe inclination with a maximum drag reduction of 25.53% at vm = 4.5 m s-1 and Cm = 25%. Uphill flows demonstrated some nonmonotonic changes in vOD and %DR, which need more experimental data for us to reach a firm conclusion. The research outcomes could help design and operate a long-distance integrated pipeline network for biomass transportation to produce biofuels on a large scale. Keywords: Biomass transport, Drag reduction, Flow regions, Frictional pressure drop, Pipe inclination, Wheat straw slurry.