Hydraulic Separation Research Articles

Issues of solid household waste disposal in the context of state environmental policy in Sevastopol

The peculiarities of the current situation with the environmental crisis require careful study of the waste recycling of previously accumulated and newly generated solid municipal waste. The use of technological developments and solutions for environmental conservation meets the most stringent ecological standards. These demands are due to the special natural and climatic status of Sevastopol. The purpose of the study is to substantiate the use of effective and simple method of sorting solid waste –hydraulic separation of solid household waste as one of the types of industrial waste separation. The article presents its advantages and possible application in Sevastopol. This advanced technology is stated to be effective in waste recycling as it provides separating unsorted waste and utilizing almost 80 percent of the volume. A feature of this method is the use of equipment manufactured for the paper industry for sorting and processing solid waste. In conclusion it is noted that the particularbenefit of the hydraulic separation is in its relative simplicity, as well as economic and environmental profits.

Combining ground stability investigation with exploratory drilling for mine water geothermal energy development; lessons from exploration and monitoring

Mine water geothermal energy's potential for decarbonization of heating and cooling in the UK has led to increased national interest and development of new projects. In this study, mine water geothermal exploration has been coupled with ground investigation techniques to assess ground stability alongside seasonal mine water hydrogeology and geochemistry. Drilling operations in late 2020 at Dollar Colliery, Clackmannanshire, Scotland, encountered mined coal seams with varying conditions (void, intact, waste, etc.), reflecting different techniques used throughout a protracted mining history. We found that time and resources spent grouting casing through worked mine seams (ensuring hydraulic separation) can be saved by accessing deeper seams where those above are unworked. Continued assessment of existing water discharges and completion of boreholes with slotted liners into mined coal seams and fractured roof strata allowed chemical and water level changes to be monitored across a 1 year period. Mine water heads and mine discharge flow rates vary seasonally and are elevated between late autumn and early spring. The mine water has a low dissolved solute content. Dissolved sulfate- 34 S isotope data suggest increased pyrite oxidation during lower water levels. These findings can inform future building decisions, whereby housing developments on site could use the mine water for heating. Supplementary material: Borehole data and completion diagrams are available at https://doi.org/10.6084/m9.figshare.22188801 Thematic collection: This article is part of the Early Career Research collection available at: https://www.lyellcollection.org/topic/collections/early-career-research

Experimental determination of the solid phase density of thermal power plant ash

Recycling of ash and slag waste from thermal power plants is an important environmental and economic task. The widespread use of ash in construction is mainly hindered by the high content of unburned carbon. The fine granulometric composition of the ash makes most mechanical methods of recycling and flotation ineffective, and is the most effective, environmentally friendly, and cheapest method is hydraulic separation. It allows for the recovery of about 70% of construction raw materials, in which the carbon content is reduced to regulatory commercial values, from 20% in raw ash to 5–10%. A central element of hydraulic separation research is establishing the hydraulic characteristics of the fly ash, with a special focus on determining its actual density, considering that the ash includes more than 10 different mineral components that have also undergone high-temperature transformation. Theoretical determination of the solid phase density of a multi-component mixture does not yield a reliable result. This article examines methods for determining bulk, true, and actual density, experimental approaches to their measurement, and the impact of various factors on these parameters. Correct density determination underlies the calculation of hydraulic characteristics of ash suspensions, the speed of hydraulic flows, and the efficiency of extracting individual components by way of hydroclassification and hydroseparation. The purpose of the research is to refine the methodology and experimentally determine the density of the solid phase of fly ash in its natural state and ash classified by size -240+40 µm, -40+0 µm, using the sample of ash from Pridniprovska TPP. The results of this work are significant for engineering when creating new technologies, for hydraulic devices recycling ash aimed at minimizing environmental impact and optimizing the use of technogenic resources. It was found that the density of the solid phase of ash from the ash dump of Pridniprovska TPP varies from 1.783 g/cm³ to 2.3, averaging 2.0 g/cm³. Variations in density are related to the inhomogeneity of the chemical composition, the presence of closed cavities in the particles. Keywords: fly ash, ash and slag waste.

The Physical Reasons to Have Underdamped or Oscillating Variable-Head (Slug) Tests: A Review and a Clarification

Variable-head permeability tests are performed in monitoring wells (MWs) or open holes between packers to assess the local value of hydraulic conductivity, K, of gravel, sand, and fractured rock. This article examines physical reasons for having an oscillating water level in the riser pipe, called underdamped (UD) response. The UD solutions are incomplete because they solve one half of the problem—for the water in the pipe—and ignore the second half, seepage in the tested material. This article shows that these half-solutions violate mathematical rules for the second half and thus, are incorrect. Four reasons for oscillations are examined: (1) solid matrix elasticity (storativity), (2) trapped gas, (3) sealing defect, and (4) hydraulic fracturing. Reason (1) yields small oscillations but not large oscillations. Reasons (2–4) can yield large oscillations and explain field data for occurrence, frequency, and damping. Thus, a free space along the casing or some trapped gas is needed to observe large oscillations. Hence, a UD slug test response only proves that the MW (or a packer) is poorly installed. This MW yields wrong values for hydraulic head, gradient, and water analyses. The data of oscillating slug tests are shown to depend upon parameters that are not easy to evaluate. This is why the UD slug tests are found to give poor estimates of K. It is recommended to use suitable drilling techniques to avoid overexcavation, to take 2–4 hours to correctly install a MW, to avoid using compressed gas to start a slug test, and to apply head differences that are high enough to have good results but lower than those producing hydraulic separation. For packer tests, it is recommended to monitor the water pressure between the packers, in the hole below the lower packer and above the upper packer, using three pressure sensors.

Hydraulic separation in spiral classifiers. Part 1. Theoretical justification for a mathematical model compiling

Hydraulic separation in spiral classifiers. Part 1. Theoretical justification for a mathematical model compiling

On the formation of a waterproofing shell around the underground structure lining in watered ground

To prevent the filtration of groundwater into the used underground structure in operation through its lining, it is proposed to make two waterproofing shells by the underground method around the outer surface of the lining of an underground structure; the upper one is made of the soil mass compacted by cementation with reduced water permeability and the lower one is made of the silicate cement. To make the upper shell, boreholes are drilled from an underground structure through its lining and the cement mortar is alternately injected through them into the watered ground providing its hydraulic fracturing; and to make the lower shell, injection pipes with a diameter of 102-152 mm are installed between the boreholes in the lining flush with its outer surface, the silicate cement mortar is alternately injected into the injection pipes, an incipient crack is created between the outer surface of the lining and the ground under the action of the mortar injection pressure on the ground opposite the injection pipe, an incipient crack is hydraulically extended along the contact of the lining with the ground and filled with the silicate cement mortar until refusal to absorb it. To determine the optimal parameters of the hydraulic separation process, tests were carried out on the laboratory table simulator.

Containment Risk Assessment of the Northern Lights Aurora CO2 Storage Site

Assessment of containment (storage site integrity) is a key activity in the evaluation, and a requirement for approval, of potential CO2 storage sites. Here we present the workflow used for, and key results of, the containment risk assessment (CRA) in the Northern Lights project, which is the transport and storage part of the Norwegian “Longship” full-scale CCS project. In the Northern Lights project, CO2 storage is planned to take place at the Aurora site (Exploitation license EL001), southwest of the Troll Field. Injection is planned into the sandstone-rich Johansen Formation (Lower Jurassic Dunlin Group). The argillaceous upper member of the Dunlin Group, the Drake Formation, provides the main seal for the storage reservoir. Several further barrier and baffle units and intervening sandstones are present between the Drake Fm. and the sand-rich units of the Viking Group, which contain the giant Troll field with a high level of depletion to date. The injection site is located downdip of – and stratigraphically deeper than – the Troll West gas province (TWGP). Injected CO2 is expected to move slowly over time buoyancy-driven up-dip (northwards), with a small proportion reaching eventually the structural trap underneath the TWGP. A key method utilized in the Aurora CRA is the bowtie method. Bowties were prepared for each identified “leakage” pathway (according to the definition in the EU CO2 Storage Directive, thus not implying any emission to the water column) instead of per “leakage” mechanism, as has been the case in previous CO2 storage CRAs. The bowties were designed to allow for updates, which took place as new data or interpretations became available. A major update occurred after drilling of a confirmation well at the planned injection site. Key results of the CRA are that the probability of any emissions into the water column due to “leakage” of CO2 out of the storage complex is very low to negligible. Important arguments for this conclusion are (i) the hydraulic separation of the Johansen Formation from the shallower, depleted Viking Group, as attested by pressure data in the confirmation well, and (ii) the proven effectiveness of the seal to the Viking Group sandstones, which have accumulated and stored hydrocarbons over geological time. Further, any CO2 reaching and blending into the hydrocarbon accumulations nearby (such as the Troll Field) is regarded to also have very low probability. Storage Complex Monitoring (SCM) is an integral element of the CRA to enable mitigating actions in case of indications for unpredicted behaviour or “leakage” of the injected CO2.

Irrigated composite liner designs for fast hydration and prevention of thermal desiccation of geosynthetics clay liners

In composite liners made of geomembrane (GMB)-geosynthetics clay liners (GCLs), maintaining bentonite in the GCL in a suitably hydrated state is critical for their performance. Hydration of GCL from subsoil, following industry best practice, is time consuming and conditional on suitable water chemistry in subsoil. In addition, under thermal gradients, dehydration occurs, with moisture migrating downwards to the subsoil, leading to the development of cracks in the bentonite and hence loss of performance.Two novel ideas are proposed in this paper, namely hydration of GCLs by artificial irrigation and hydraulic separation of the liner system from the underlying subsoil. Three new composite liner designs allowing for actively irrigating a geosynthetic clay liner (GCL) through a geocomposite layer were investigated. In two of the three designs, the hydraulic connection between the GCL and the subsoil was broken by placing an additional GMB between them. The new designs were tested in column experiments under 20 kPa overburden pressure and temperatures of up to 78 °C applied to the top of the liner. The performances of the new designs were compared to that of a standard GCL-GMB design where GCL was allowed to hydrate from a well-graded sandy subsoil. Three scenarios for the staging of hydration and thermal load application were investigated.Under active hydration of the composite liners, it took less than 14 days for the GCLs to reach a gravimetric water content ω of 110–130%, compared to 49 days taken to reach ω~95% under hydration from the subsoil. GCLs in the new designs in which the hydraulic connection with the subsoil was broken, remained well-hydrated (ω>100%) after 14 days of heating and no cracks appeared in the bentonite. On the other hand, the GCL in the conventional design experienced severe desiccation under the same conditions. The new designs hence offer a viable solution to the problem of slow hydration and/or thermal desiccation of GCLs.

Hydrodynamic optimization of multi-environment reactors for biological nutrient removal: A methodology combining computational fluid dynamics and dimensionless indexes

Multi-environment reactors are an innovative alternative to simplify conventional Biological Nutrient Removal (BNR) treatment trains as they are more compact and can adapt to existing quality requirements. However, maintaining the desired environmental conditions in different zones of the reactor implies the need for deflectors or mixing devices that generate a complex hydrodynamic behaviour. Therefore, to ensure the desired biological efficiency, hydraulic optimization is essential. For that purpose, a hydrodynamic optimization methodology combining Computational Fluid Dynamics (CFD) and dimensional analysis is developed and presented in this work. The methodology is applied to AnoxAn, an anaerobic-anoxic reactor for BNR. The CFD model is constructed using the OpenFOAM® open source toolbox and has been already validated in a previous work by the authors. Different features as hydraulic separation, dead volumes, short-circuiting or mixing performance are evaluated and main results show that configurations of AnoxAn with high slenderness have the most efficient hydrodynamic behaviour.

INFLUENCE OF DIFFERENT TEMPERATURES AND AIRFLOWS ON DRYING OF NATURAL AND PULPED COFFEE

This study aimed to evaluate drying kinetics for natural and pulped coffee, using different temperatures and drying airflows. For the conduction of the experiment, coffee fruits (Coffea arabica L. cv. Topázio) were harvested manually, selecting only ripe fruits and subsequent to the hydraulic separation. For drying the coffee, use a mechanical dryer with two temperatures (40 and 45°C) and four drying air streams (24; 60; 96 and 132 m3.min-1.m-2). Twelve models for employees to describe the drying kinetics of coffees. Among the models used to describe the drying process of natural coffee and pulped coffee, according to the results of the coefficient of determination, relative mean error, standard deviation of estimates and distribution of waste distribution, proposed model for the only one that presents fit for all as conditions study. The temperature of 45 ° C and the airflows of 96 and 132 m3.min-1.m-2 provide the shortest drying times regardless of the coffee processing type.

Improvement of the bitumen extraction technology from bituminous sand deposits

Today considerable experience in the development of tar sands is accumulated. However, well-known mining technologies do not cover the entire depth range of natural bitumen deposits. In addition, there are significant energy-intensive technologies and negative environmental impacts. In view of this, the purpose of this work is to improve the method of extracting natural bitumen in site for a deposit interval of 75 – 200 m and to substantiate the basic technological scheme of this method. The proposed method of extracting bitumen from poorly cemented reservoirs in the depth range of 50 – 400 m provides: creation of artificial mine working; the transfer of the rock into the water mixture composition under the action of high pressure jets of a heated mixture of water, a hydrocarbon solvent and a flotation agent; separation from the rock and concentration of bitumen in the production as a result of its heating, dissolution and flotation; selection of depleted bitum slurry from the mine working by gas lift method. The proposed method of extracting bitumen is the transfer of the rock at the site of its occurrence to the suspension condition on the excavation created by the hydraulic production method, separation and concentration of bitumen by dissolving it with a heated hydrocarbon solvent and a flotation agent (hydrocarbon reagents), and extraction in the composition of depleted rock slurry to the surface by the gas lift method. As the preliminary calculations show, the proposed method will allow the efficient extraction of bitumen and highly viscous oil from weakly cemented reservoirs in the depth range of 50 – 400 m. Also, the proposed technology creates the preconditions for the development of oil sands at a depth of 75 – 200 m since there is currently no effective technology for the interval. In addition, it can significantly reduce energy costs, environmental pollution and greenhouse gas emissions.

Multi-level separation of particles using acoustic radiation force and hydraulic force in a microfluidic chip

Combined with acoustic separation and hydraulic separation technology, a microfluidic chip, which can achieve multi-level particle separation, is proposed in this work. The chip uses the sheath flow on both sides to align the mixed particles in the set area (near the side of the channel) of the separation channel. And then, the mixed particles successively pass through the acoustic surface wave and hydraulic action area, which are generated by modulating interdigital transducers and adjusting the flow ratio, respectively, and finally realize multiple particle separation under the acoustic radiation and hydraulic force. The corresponding separation experiments were carried out using polystyrene (PS) microparticles with diameters of 1 µm, 5 µm, and 10 µm, respectively. Moreover, we explored the influence of the peak-to-peak voltage (Vpp) and flow ratio on the PS microparticles separation effect, and the separation effect is optimal at the flowrate in the main channel is 4 mm/s, Vpp = 25 V, A1 = 0.2, A2 = 0.5. Under these conditions, the separation purity of 1 µm, 5 µm, and 10 µm PS microparticles are 95.60%, 91.67%, 93.75%, respectively, and their separation rates are 96.67%, 89.19%, and 96.77%, respectively. The combined multi-level separation chip has the advantages of simple structure, high separation accuracy, high separation efficiency, and the ability to sort multiple particles, which can be applied to chemical analysis, cell sorting, biomedicine.

Relationship between the Uranium Concentration and the Upgrading of El-Sibaeya Phosphate Ore by New Physical Processes.

Phosphate plays a significant economic role in developing countries because the phosphate rock is consumed in the agricultural sector as fertilizers and animal feedstocks as well as used in the manufacture of high-grade phosphoric acid used in the manufacture used in pharmaceuticals, detergents, food products and other industrial uses. So, this research focus is represented in how to apply some new physical concentration processes derived from ore dressing to arise the concentration of P2O5 (21.14%) in sample of 10 Kg of low grade Egyptian phosphate ore was collected from East El-Sibaeya region as an alternative method to the existing calcination method, which is not friendly environment and has several disadvantages and accordingly the find relationship between the uranium concentration and the upgrading of El-Sibaeya phosphate ore. Upgrading the phosphate ore is done through crushing, screening, up current Classifiers, gravimetric separation and hydraulic separation. The results of this study led to achieve the desired product (high grade of phosphate) which is imperative to meeting market requirements, and at optimum conditions gave a product which analyzed P2O5 (33.63%), CaO (47.66%), MgO (0.57%), SiO2 (4.91%), NaO2 (0.49%), K2O (0.89%), Al2O3 (0.64%), Fe2O3 (1.25%) and U (172.12 ppm).

Improvement of Low-grade rutile using chemical and physical processes

This paper describe improvement of Low-grade rutile Rutile is very important mineral for several industrial applications . So, in this work we will discuss the physical and chemical methods which are used to beneficiation of low grade rutile sample (10 Kg ) was collected from Abu Khashaba beach area at the Mediterranean cost ( Fig. 1 ) . The leach process whereby iron coatings around rutile particles is removed by the addition of sulphuric acid at 20 wt% to mineral at 160°C .Then the sample is sent for the physical processes which include up-current classifiers, gravimetric separation, hydraulic separation and magnetic separation . Stereo microscope and XRF analyses were used to study heavy and light mineral fraction .Rutile identification is established and the results at optimum conditions gave a high grade of rutile product which analyzed 95.8 % Ti with 0.8 % Fe, 1.8 % Zr and 0.80 % Nb.

Long-Term Permeability Characteristics of Soil-Geosynthetic Combination Used in Landfill Covers

Abstract Multilayered cover system (MLCS) forms an integral part of engineered landfills nearing closure. Geosynthetic materials find multiple applications in MLCS as hydraulic barrier, drainage, separation, and filtration layers. Performance of geosynthetics used as filters needs to be well understood to ascertain the stability of MLCS. The main objective of this study is to investigate the compatibility of the soil-geosynthetic combination by long-term permeability tests. The compatibility of five different types of geosynthetics was evaluated with respect to two different gradations of red soil (RS) and RS–fly ash (FA) 50:50 mix. The results of long-term permeability and clogging characteristics were used to judge the effect of soil type, soil gradation, and type of geosynthetics on soil-geosynthetic compatibility. The efficacy of geosynthetics as filters was established based on (1) permeability improvement factor, which is defined as the ratio of the permeability of soil-geosynthetic composition to the permeability of the soil, and (2) stabilization time, i.e., the time required by the soil-geosynthetic system to achieve hydraulic equilibrium. It was noted from this study that the soil type and gradation had significant effect on the long-term permeability variation. The effect of the geosynthetic on the soil-geosynthetic combination is governed by its pore-size characteristics and was found to be marginal in this study. The stabilization time of a soil-geosynthetic combination increases with increase in soil fines content. The cyclic variation in permeability with time for a particular soil was found to be similar when different geosynthetics were used. Irrespective of soil type, higher permeability improvement factor was observed in the case of a woven multifilament geosynthetic and less in the case of a geocomposite. The class F FA in conjunction with RS was found to be compatible with the geosynthetics used in this study.

Platinum-Group Metals in Residual Soils and Potential Efficiency of Their Processing in Gravity Concentrators

The authors analyze geochemical data on residual soils of Svetloborsk and Nizhny Tagil massifs of the Ural Platinum Belt after tests aimed to determine content of platinum group elements, gold and silver in different zones of geological cross section. The scope of the analysis embraces theory of gravity concentration in the flows of suspended matter. The criterion of efficient dressability in gravity concentrators (hydraulic separation coefficient) is adapted as an alternative to the equal-settling factor inclusive of the influence of a particle shape. The presented calculated coefficients of hydraulic separation for different shape particles of olivine and platinum prove that flattened particles are separated more efficiently with centrifugal gravity concentrators. The theory is backed with the experimental data, and the conclusion on applicability of the proposed hydraulic separation coefficient is drawn.

Recent Progress in the Experimental Study of LPCE Process on “EVIO” Pilot Plant

A new LPCE column (LPCE-3) of 2 m packing height and 50 mm inner diameter expands the experimental potential of “EVIO” pilot plant. Fresh RCTU-3SM catalyst of somewhat greater average percentage of Platinum and a little larger dimension of SDBC carrier has been tested in LPCE-3. Both hydraulic and isotope separation characteristics of LPCE-3 filled with alternating layers of the catalyst and packing in the volume ratio of 1:4 (the same packing and ratio which are used in LPCE-1 and LPCE-2 columns) have been studied. The experimental results are presented in comparison with ones received on LPCE-1 and LPCE-2 earlier. This paper aims to the problem of comparing different columns operated at dissimilar conditions and separating different isotopes. In the search for an invariant, which would unambiguously present performance of LPCE, it is experimentally shown that performance expressed by a 3-fluid model characteristic, Kc – mass-transfer coefficient for catalytic exchange (at fixed mass-transfer coefficient for phase exchange) is the same for different isotopes and different temperatures in contrast to the overall mass-transfer coefficient, Kya.

Simulation on mechanism of contamination mitigation through Higee and hydrocyclone techniques in fluid power system

In this study, an innovative Higee hydraulic oil purification device capable of removing the solid particle contaminants and water moisture simultaneously is developed for dealing with the contamination control problem of fluid power systems. The purification device is considered as a combination of two units (hydrocyclone separator and rotating packed bed) according to different separation functions. The mathematical models about the migration regularity and dynamic behavior of different phases have been established, in which discrete phase model model is employed to simulate the solid particles – hydraulic oil separation, and Eulerian model is selected as the multiphase simulation model to simulate the hydraulic oil – water moisture separation. Simulation results demonstrate that the hydrocyclone separator can remove solid particles of 5 to 15 µm, while the rotating packed bed can mitigate water moisture. The results indicate that the developed Higee hydraulic oil purification device can provide an effective and efficient manner for controlling the contamination level of fluid power systems.

Multi-well and multi-tracer tests to characterize the groundwater aquifers in southern Kuwait

In the water-starved arid climate of Kuwait, useable (both fresh and brackish) reserves of groundwater constitute a strategic resource. Therefore, effective management policies are essential for ensuring sustainable management of the groundwater resources in the state. Although the general pattern of groundwater flow is known, the detailed pattern of the flow paths of water within the Kuwait aquifer system and the variation of hydraulic and transport properties are not known. Applied tracers are powerful hydrogeological investigative tools because the tracer application (source term) is controlled and well characterized which permits quantification of subsurface properties often unmatched by standard physical methods. Aquifer pumping tests and multi-well and multi-tracer (rhodamine-WT, fluorescein, sodium bromide) tests were carried out, under both natural and forced gradient conditions, at Al-Shegaya and Umm-Gudair sites. The objectives of the tracer tests are to determine the groundwater flow directions, flow rates, inter- and intra-aquifer hydraulic communications, effective porosity, dispersivity, etc., in the established groundwater well fields of southern Kuwait at Al-Shegaya Umm-Gudair. The tests involved drilling, construction and development of groundwater wells, and injection of tracers in the injection wells and monitoring its concentrations in the injection and monitoring wells. Inverse numerical modeling (MODFLOW and MT3DMS codes) was used for data interpretation. The Kuwait Group and Dammam Formation have a high degree of hydraulic separation, and it is likely that there is little recharge of the Dammam Formation from downward leakage from the Kuwait Group (at least in the study area). Groundwater resources in the Dammam Formation may be largely restricted to the flow into Kuwait from Saudi Arabia. The lower Kuwait Group aquifer has dual-porosity conditions: likely a rapid flow through fracture and/or conduit system (neff = 0.5 %) and a slow flow through the formation (calcareous) matrix (neff = 20 %), with very low dispersivity (longitudinal and transverse/vertical dispersivities of 0.1 and 0.01 m, respectively). The injection wells indicate more than one linear line segment in the tracer dilution plot (concentration in natural logarithmic vs. time), which suggests varying transmissivity across the well screen depths. The filtration velocity, hydraulic conductivity and transmissivity of the aquifers have also been estimated. At both the sites, the groundwater flow in the underlying carbonate formation is very slow (0.028 m/d). The hydrogeological parameters obtained from the present tracer study will be used for more reliable conceptualization, development and calibration of a suitable statewide flow and solute transport model for the regional groundwater system of Kuwait.

Improving treatment technology stump fatwood pulse-rotational jets

The paper deals with purification stump wood from the ground, bark and of rot, with subsequent use it in production. The choice of cleaning stump wood pulse-twirled hydraulic jets. Developed stationary line hydraulic cleaning stump fatwood pulse-swirl jet, using «gidroimpulsator» device. Are determined in general form regression equations influence independent of the initial parameters of pulse-hydraulic swirling jets to the width of the machined surface stump wood when removing soil, bark and rot. The investigated characteristics of the pulse swirling liquid jets and main modes of operation of the plant used for cleaning stump fatwood. The results of experimental studies. The basic operation modes for cleaning hydraulic separation with stump substandard wood and soil, bark and rot.