Measurement Of Solids Content Research Articles

A Solid Concentration Measurement Method With Online Calibration of Solid Permittivity

A Solid Concentration Measurement Method With Online Calibration of Solid Permittivity

Simultaneous measurement of solid concentration and solid moisture in gas–solid two-phase flow using a dual-modality electrical sensor

Abstract In a gas–solid two-phase flow system, simultaneous measurement of solid concentration and solid moisture is essential for some applications. However, during the measurement process, solid concentration and solid moisture are coupled in the measurement signals when the measurement signal is sensitive to both solid concentration and moisture. This makes it challenging to measure them simultaneously in the same measurement field. To solve this issue, a novel measurement method is proposed in this study, which uses a dual-modality electrical sensor to achieve simultaneous measurement of solid concentration and solid moisture in gas–solid two-phase flow. The dual-modality electrical sensor features a simple structure and captures measurement signals of capacitance and angle of dielectric loss within the same measurement section. With the above signals which are both sensitive to solid concentration and moisture, an iterative correction calculation method is adopted to achieve the simultaneous measurement of solid concentration and solid moisture. During the calculation process, the measured parameters are decoupled and continuously corrected until the related error values meet the threshold requirement. Numerical simulation experiments under three typical distributions and physical experiments under roping flow are carried out to verify the proposed measurement method. The results prove the effectiveness of the proposed measurement method in the simultaneous measurement of solid concentration and solid moisture for gas–solid two-phase flow.

Measurement of Solid Concentration in Gas–Solid Flows Using a Microwave Resonant Cavity Sensor

Measurement of Solid Concentration in Gas–Solid Flows Using a Microwave Resonant Cavity Sensor

Design and evaluation of a volatile particle remover combining hot dilution and a thermodenuder

Portable and efficient removal of volatile particles from motor vehicle exhaust is essential for the accurate measurement of involatile solid particle number concentration in on-board emission measurement systems. For this purpose, a volatile particle remover with a combination of hot dilution and a thermodenuder (referred to as VPR-TD) was designed. The flow and temperature fields of the VPR-TD were simulated and analyzed by COMSOL Multiphysics software by which experimental verification and system performance tests were performed. The simulation showed that the effective heating length and residence time of the VPR-TD increased by 6 cm and 25%, respectively, as the dilution ratio increased from 1 to 10 at a total flow of 0.6 L/min at 350 °C. In addition, the experimental results showed that the penetration efficiency of 100 nm sodium chloride (non-volatile particles) in the VPR-TD was higher than 70.4%, and the removal efficiency of 30 nm tetracontane (volatile particles) was higher than 99% at a total flow 0.6 L/min, heating temperature 350 °C, and dilution ratios of 5 and 10. In summary, when the dilution ratio was set to 10, the device met the requirements of the Light Duty Vehicle Emission Limits and Measurement Methods (CHINA 6) for a volatile particle remover. At dilution ratio of 5, VPR-TD may be used as a pre-conditioning unit in portable emissions measurement systems.

Sub-millimetre wave range-Doppler radar as a diagnostic tool for gas-solids systems - solids concentration measurements

Current non-intrusive measurement techniques for characterising the solids flow in gas-solids suspensions are limited by the low temporal or low spatial resolution of the sample volume, or in the case of optical methods, by a short range of sight. In this work, a sub-millimetre wave range-Doppler radar is developed and validated for non-intrusive sensing of solids concentrations in a gas-solids particle system with known characteristics. The radar system combines favourable features, such as the ability to see through at optical frequencies opaque materials, to measure the local solids velocity and the reflected radar power with a spatial resolution of a few cubic centimetres over distances of a few metres. In addition, the radar hardware offers flexibility in terms of installation. After signal processing, the output of the radar is range-velocity images of the solids flowing along the radar’s line-of-sight. The image frame rate can be close to real-time, allowing the solids flow dynamics to be observed.While the well-established Doppler principle is used to measure the solids velocity, this paper introduces a method to relate the received radar signal power to the solids volumetric concentrations (cv) of different particulate materials. The experimental set-up provides a steady stream of free-falling solids that consist of glass spheres, bronze spheres or natural sand grains with known particle size distributions and with particle diameters in the range of 50–300 µm. Thus, the values of cv found using the radar measurements are validated using the values of cv retrieved from closure of the mass balance derived from the measured mass flow rate of the solids stream and the solids velocity. The results show that the radar system provides reliable measurements of cv, with a mean relative error of approximately 25 % for all the tested materials, particle sizes and mass flow rates, yielding values of cv ranging from 0.2 × 10-4m3/m3 up to 40 × 10-4m3/m3 and solids velocities within the range of 0–4.5 m/s. This demonstrates the ability of the radar technology to diagnose the solids flow in gas-solids suspensions using a unique combination of penetration length, accuracy, and spatial and time resolution. In future work, the radar technique will be applied to study non-controlled solids flow at a larger scale, and to understand flow conditions relevant to industrial reactor applications, e.g., fluidised bed, entrained flow, and cyclone units.

Potential of kaffir lime (<em>Citrus hystrix</em>) leaf extract as biopesticide in improving pre and post-harvest quality of chili (<em>Capsicum annuum</em>)

Purpose: Chilli production in Malaysia is declining due to production problems such as pest and diseases which cause plants to become stunted, unhealthy, and damaged. To overcome this problem, most farmers prefer using chemical fertilizers and pesticides due to their fast reaction and effectiveness. In long term, application of these chemicals input may lead to an environmental damage and human health problems. To conserve our nature, the use of natural input in agriculture is highly recommended. Research Method: This study was conducted to identify the potential of plant extract, namely kaffir lime in increasing the plant productivity and reducing the severity of pests for chilli trees. The study was performed by spraying the chilli trees with 25, 50, and 75% (v/v) kaffir lime extracts. Controls consisted of plants without any treatment as negative control and plants applied with a commercial chemical pesticide as positive control. Findings: Results indicated that there were significant differences (p<0.05) between treatments with respect to all parameters including pre-harvest (plant height and pest severity) and postharvest (fresh weight and number of chilli pods) parameters except for the stem and crown diameter, soluble solid concentration, fruit firmness and colour measurement of chilli. The results found that chilli plants sprayed with 25% kaffir lime extract had the lowest pest infestation. Moreover, application of the 25% kaffir lime extract had produced the heaviest weight of chilli fruits and the highest number of chilli pods compared to other treatments including the positive control (chemical pesticide). Therefore, it was concluded that 25% kaffir lime extract produced healthier chilli plants, higher yield and better quality of chilli. Originality/ Value: Limited number of studies are available on eff ectiveness of kaffir lime-based insecticides. Therefore, this study was conducted as an effort towards understanding the versatility of kaffir lime leaves extraction as an alternative pesticide on chilli plants’ pre- and postharvest performance.

Eliminating the influence of moisture on solid concentration measurement in gas-solid flows using combined sensors

In gas-solid two-phase flow, the situation that the moisture in the solid changes is often encountered. The varying and unknown moisture brings new challenges to the solid concentration measurement if the used measurement method is sensitive to the moisture. In this study, a new method which can eliminate the influence of moisture on the measurement of solid concentration in gas-solid flows is proposed. Firstly, the new combined sensors consisting of the microwave transmission sensor and the capacitance sensor are proposed and the measurement systems are designed. The microwave transmission sensor and the capacitance sensor are both sensitive to the moisture and the solid concentration, and they can acquire the information of the solid concentration and the moisture simultaneously. Then an effective decoupling method is proposed to derive the moisture and the solid concentration from the information acquired by the microwave transmission sensor and the capacitance sensor. Experiments are carried out to simulate the flow structure of roping flow to verify the proposed method. The results indicate that the influence of moisture on the measurement of solid concentration can be eliminated, and moisture independent measurement of solid concentration in gas-solid flows can be realized.

Suspended particles behavior in aqueous [Bmim]BF4 solution by novel on-line electrical sensing zone method

Ionic liquids (ILs) and aqueous ionic liquid solutions have been investigated as excellent solvents or catalysts in a few multiphase systems. To optimize the reactor design and operation conditions, it is significant to study the suspended particles behaviors in ILs involved solid–liquid mixing processes. A novel on-line electrical sensing zone (ESZ) method is developed to achieve the measurement of local solids concentration in aqueous [Bmim]BF4 conductive solutions. The suspension degrees of solid particles stirred by different impellers at varied agitation speeds have been obtained. The mean fluid velocities and turbulent fluctuating velocities close to the bottom of the unbaffled tanks have been determined by stereoscopic particle image velocimetry (SPIV). The results showed that the aqueous [Bmim]BF4 solutions are more efficient on solids than normal saline solution. Radical flow impeller with wider blades at C/T = 0.2 presents its better performance on solids suspension. The variations of solids suspension curves are more consistent with that of mean radial velocities at axial height of z/H = 0.99. It indicated that the solids suspension in unbaffled stirred tanks is mainly related to the mean flow rather than to turbulent fluctuations.

Measurement of solids concentration in aqueous slurries for monitoring the solids recovery in solid bowl centrifugation

Solid bowl centrifugation (SBC) is widely used for various solid-liquid separation tasks in mineral and coal processing. The SBC often suffers from a relatively high solids loss during the separation process, mainly owing to lack of an effective tool that can monitor the solids recovery. Despite its importance, the information on monitoring the solids recovery in the solid bowl centrifugation is scarce. In the present study, a strong correlation between an index (defined as the ratio of the solids concentration of the effluent by weight to the solids concentration of the feed by weight) and the solids recovery in solid bowl centrifugation was identified based on analysis of the data available in the literature. In an attempt to use this correlation for monitoring the solids recovery, a novel solids concentration measuring tool was developed to measure the solids concentration of a slurry. The tool consists of a slurry image acquisition apparatus and the backend interpolation algorithm to retrieve the concentration information from the recorded slurry images. A hybrid of the convolutional neural network and the long short-term memory network, coined as SConcNet, was built and trained with a newly created database. The SConcNet achieved a high level of accuracy and reliability in measuring the solids concentration by weight. The potential of using the index and the developed solids concentration measurement method to monitor the solids recovery of the SBC in real-time was also discussed.

A novel method to improve Electrical Resistance Tomography measurements on slurries containing clays

Electrical Resistance Tomography (ERT) is a robust and proven technique for slurry flow measurements. The presence of surface-active clays in mineral tailings makes it difficult to make accurate solids concentration measurements using ERT. To evaluate ERT performance under such conditions, measurements on pipeline flows of concentrated clay/water/sand mixtures were performed using ERT. Traversing gamma-ray densitometry and Gamma-Ray Tomography (GRT) systems installed on the pipe loop were used as reference instruments. The results showed that ERT performance is sensitive to clay concentration and is more accurate at lower clay and higher coarse solids (sand) concentrations. A concentration correction model based on a modified Archie's law was developed to compensate for the effect of clay on ERT measurements. The implementation of the correction model was found to significantly improve the accuracy of the ERT measurements on slurries containing clays.

Calibration of solids concentration optical fibre probes with solids‐polymer blocks

AbstractOwing to the determinant effects of the local distribution of solids concentration on transport phenomena, particularly in gas‐solids flows in such processing units as gas‐solid fluidized beds and pneumatic conveying lines, its accurate measurement has received considerable attention. Despite the widespread applications of optical fibre probes for the measurement of local solids concentration, these instruments may create measurement uncertainties due to their structural designs and challenges in their accurate calibrations. Several calibration methods have been proposed in the literature, while they need to be further improved. In the present study, we calibrated in‐house, fabricated, solids concentration mixed parallel optical fibre probes by two sets of solids‐polymer blocks covering solids volume fractions in the range of 0‐0.30. The uniform blocks were produced by a twin‐screw extruder and an injection moulding machine. FCC particles, 86 μm in diameter, formed the dispersed solids in the blocks, while poly styrene and poly methyl methacrylate were separately acting as the transparent medium. They helped us investigate the effects of the refractive index of the medium and the probe tip design on the calibration curve. The blind distance (zone) in front of the adopted probes was determined, at about 0.70 mm, upon measuring their reflective curves. Two glass windows with 1.00 and 1.60 mm thicknesses were separately installed at the tip of a probe to study their effects on the calibration curve. Experimental results indicated that in the absence of a glass window, the probes' voltage readings varied nonlinearly with solids concentration, the voltage readings were higher for blocks with a higher refractive index of the transparent medium, while the normalized calibration curves were similar for both sets of solids‐polymer blocks. In addition, the extent of the uniform distribution of illuminating and reflecting fibre strands at the tip of a mixed parallel optical fibre probe can change the degree of nonlinearity of its calibration curve. The application of glass windows thicker than the blind distance decreased the degree of nonlinearity of the calibration curve, yet did not completely eliminate it.

Development of suspended solid concentration measurement technique based on multi-spectral satellite imagery in Nakdong River using machine learning model

Development of suspended solid concentration measurement technique based on multi-spectral satellite imagery in Nakdong River using machine learning model

Experimental flow structure analysis in a 1 MWth circulating fluidized bed pilot plant

A water-cooled dual-channel capacitance probe system was developed for in-furnace measurements of solids concentration and solids velocity in a 1MWth dual fluidized bed pilot plant. Measurements were conducted in both reactors of the pilot plant during carbonate looping and combustion test campaigns. Solids velocities were derived by cross correlating the signals of the two channels of the capacitance probe. Thus, horizontal profiles of solids concentration and velocity were simultaneously determined in the reactors. These profiles show a strong core annulus flow structure in both reactors of the pilot plant. The influence of bed material characteristics, operating conditions as well as riser geometries on the particle flow structure is evaluated.

Comparison of standardized methods for suspended solid concentration measurements in river samples

SSC (Suspended Solid Concentration) measurements in rivers are a complex scientific issue. Many questions arise on the spatial and temporal distribution of particles throughout a cross-section, on the properties of particles and grain-size, and also on the sediment transport capacity of streams and rivers. In this study, we focused on the SSC and grain size distribution measured from river samples, automatically or manually acquired. Many agencies suggested slightly different methods for measuring SSC: The European standard NF EN 872, which related to the US EPA 160.2 requires sub-sampling using shake-and-pour aliquot selection. The APHA 2540D requires sub-sampling by pipetting at middepth in the original sample shaken with a magnetic stirrer. These methods lead to significant uncertainty when particles larger than 63 μm are present in the samples. The ASTM D3977 analysis method, endorsed by the USGS is more accurate to capture and quantify particles larger than 63 μm. In this study we confirm the sub-sampling problem in a large concentration range using a set of samples from an alpine river.

Strawberry cultivars vary in productivity, sugars and phytonutrient content when grown in a greenhouse during the winter

Abstract In many areas of the US, fresh locally grown berries are not available during the winter. With this in mind, a research study comprised of three experiments was conducted focused on cultivar selection for berry yield, number, sweetness and phytonutrient content. Using a capillary mat system with under bench heating within a double-layer polyethylene greenhouse, strawberries were grown in the Great Plains Region of the US during the winter. During experiment 1, 12 cultivars were grown; berries were weighed, counted and analyzed for sugars and phytonutrients. ‘Albion’ plants produced a high number/mass of berries, had relatively high sugar content but a lower level of phytonutrients when compared to other cultivars. Sugar and phytonutrients concentrations overlapped across cultivars and thus, one cultivar could not be statistically singled out as best. As all cultivars flowered and fruited, two additional 8-month-long experiments were conducted. It took only 7 weeks from potting of dormant crowns for most cultivars to produce fruit. Certain cultivars fruited more successfully during certain months than others, but this was not associated with response time. For example,’ ‘Albion’, ‘Chandler’, ‘Darselect’, ‘Evie-2′ and ‘Seascape’ plants consistently produced fruit October to early January while ‘AC Wendy’, ‘Cavendish’, ‘Honeoye’ and ‘Strawberry Festival’ plants mainly produced berries in March/April. Summed over experiment 2, ‘Albion’, ‘ Cavendish’, ‘Chandler’, ‘ Evie-2’, ‘Portola’ and ’Seascape’ plants produced the greatest mass of berries. ‘AC Wendy’ and ‘Darselect’ berries contained some of the highest levels of sugars while berries from ‘Chandler’, ‘Darselect’, ‘Evie-2′, ‘Seascape’ and ‘Strawberry Festival’ had some of the highest phytonutrient values. In the third experiment, of the 8 selected cultivars, ‘Evie-2′, ‘Evie−2+’ and ‘Portola’ plants had the highest total yield and average berry mass/plant. ‘Seascape’ and’ Chandler’ plants were second in total production. Glucose, fructose and sucrose levels varied across cultivars with ‘Chandler’ and ‘Seascape’ berries possessing the lowest level of total sugars. Phytonutrient values varied among cultivars with some having better flavonoids (‘Seascape’), phenols (‘Seascape’ and ‘Chandler’) and ant oxidant capacity (‘Seascape’, ‘Evie-2’ and ‘Cavendish’). Measurement of soluble solids concentration varied by week among the cultivars with ‘Seascape’, ‘Seascape+”, and “Albion” berries possessing higher levels than other cultivars such as ’Cavendish’. Overall, under these winter greenhouse conditions using capillary mat fertigation and an under-bench heat delivery system, strawberries were successfully produced for the off-season market.

Horizontal secondary gas injection in fluidized beds: Solid concentration and velocity in multiphase jets

High speed gas injection through nozzles is used in fluidized bed technology for controlling particle size or adding a reactant. Experiments were carried out to investigate the flow field of glass beads (x1,2=92μm) in multiphase jets (with respect to the applied pressure). Particle image velocimetry (PIV) was used in a semicircular fluidized bed with optical access, to analyze the particle movement. It was found that higher gas pressure at the nozzle inlet initially leads first to higher particle velocities but decreases the particle degree of mixing. In subsonic conditions the trend of the measured data could be predicted by a simple force balance model. Additionally, the transition from subsonic to choked flow conditions inside the nozzle could be distinguished by analyzing the jet opening angle. The fluidization velocity showed no significant influence in these investigations. It was also proven by solid concentration (1−ε) measurements with capacitance probes: Increasing kinetic gas energy at the nozzle inlet leads to lower solid concentration at the jet axis. At very high gas pressures there were almost no particles in the jet. Finally, a relatively new measurement technique was used for flow analysis. A fast gantry X-ray CT was used to analyze the turbulent flow without disturbing it. Thanks to a calibration the solid distribution could be made visible. This showed an entrainment zone close to the nozzle exit. The results showed that the kinetic energy of solids can be increased by applying higher gas velocities. However, very high gas velocities lead to reduction of solid entrainment into the jet.

An instrumentation system for multi-parameter measurements of gas-solid two-phase flow based on Capacitance-Electrostatic sensor

In this paper, an instrumentation system for the measurements of local solid volumetric concentration, local solid velocity, local solid mass flowrate and solid mass flowrate in gas-solid two-phase flow system is developed. It is based on a new type of a Capacitance-Electrostatic sensor (CES). The CES sensor is mainly composed of a capacitance electrode array and two electrostatic electrode arrays. The optimum design of the sensor is achieved by finite element method. The capacitance electrode array is employed to detect the solid distribution over the cross-section of the pipe, and the local solid volumetric concentration measurement is further derived. The electrostatic electrode arrays are used to measure the local solid velocities in conjunction with cross-correlation method. From the local solid velocity and local volumetric concentration, the solid mass flowrate and the local solid mass flowrate can be achieved. The developed system for the local solid volumetric concentration measurement is verified through analogue simulation experiments and static experiments. Finally, the system is employed to measure the local solid volumetric concentration, local solid velocity, local solid mass flowrate and solid mass flowrate on a belt conveyor. The experimental results show that the measurement error of the local solid volumetric concentration measurement results are less than 10.43% for solid local volumetric concentration ranging from 0.02 to 0.56, the standard deviations of the local solid velocity measurement results are less than 0.42 for solid velocity ranging from 3.5 m/s to 15.0 m/s, and the relative error of the solid mass flowrate is within −19.6% to +14.9% for solid mass flowrate ranging from 0.006 kg/s to 0.103 kg/s, indicating that the system is capable of achieving multi-parameters measurement in gas-solid two-phase flow system.

Solids volume fraction measurements on riser flow using a temporal‐histogram based DIA method

In this article we introduce a temporal histogram‐based method for digital image analysis (DIA) of pseudo‐2D fluidized bed risers. This method enables an accurate whole field measurement of the solids volume fraction in lab‐scale pseudo‐2D riser flows by successfully removing image imperfections and merely accounting for the particles’ intensity. Moreover, the new correlation between normalized intensity and solids volume fraction that is proposed in this work enables a quantitative approach for solids concentration measurements by DIA techniques. This technique can be easily adjusted with experimental settings and shows a great stability against adverse imaging conditions. The combination of this parameter‐free method with particle image velocimetry under riser flow conditions has been successfully applied, enabling the experimental acquisition of full field hydrodynamic data. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2681–2698, 2016

Determination of volumetric concentration of solids in vertical pipeline hydrotransport

This paper presents an application of radioisotopes with reference to the determination of the solid phase volumetric concentration in a hydromixture by calibration of the measuring set. It shows how the gamma absorption equipment consisting of radioactive isotopes 241 Am and scintillation probe, may be applied to the measurement of solid particles volumetric concentration in a flow. It is based on fact that the intensity of a gamma beam decreases as it passes through matter. In the described experiments as solid phase the ceramic models representing natural polymetallic ocean nodules were used. The especially constructed calibration stand and obtained relation between the related intensity of radiation and mean volumetric concentration of the solid phase are presented.

Enhancement of Uniformity of Solid Particles in Spouted Bed Using Stochastic Optimization

Performance of gas-solid spouted bed benefit from solids uniformity structure (UI).Therefore, the focus of this work is to maximize UI across the bed based on process variables. Hence, UI is to be considered as the objective of the optimization process .Three selected process variables are affecting the objective function. These decision variables are: gas velocity, particle density and particle diameter. Steady-state solids concentration measurements were carried out in a narrow 3-inch cylindrical spouted bed made of Plexiglas that used 60° conical shape base. Radial concentration of particles (glass and steel beads) at various bed heights and different flow patterns were measured using sophisticated optical probes. Stochastic Genetic Algorithm (GA) has been found better than deterministic search for study mutation of process variables of the non-linear bed. Spouted bed behaved as hybrid system. Global GA could provide confirmed data and selected best operating conditions. Optimization technique would guide the experimental work and reduce the risk and cost of operation. Optimum results could improve operating of the bed at high-performance and stable conditions. Maximum uniformity has been found at high-density, small size of solid beads and low gas velocity. Density of solids has been effective variable on UI.Velocity of gas and diameter of solid particles has been observed more sensitive decision variables with UI mutations. Uniformity of solid particles would enhance hydrodynamic parameters, heat and mass transfer in the bed because of improving of hold-up and voids distributions of solids. The results of the optimization have been compared with the experimental data using sophisticated optical probe and Computed Tomography technique.