Tubular Filter Research Articles

Aspiration of loading iron ore pellets into railway wagons using a ceramic filter.

Loading of iron ore pellets into railway wagons at mining and processing enterprises is accompanied by the formation of a significant amount of suspended iron-containing highly abrasive particles. The shortcomings of existing aspiration systems currently used to reduce the negative impact on the environment are considered. It is demonstrated that existing wet cleaning devices, as a rule, do not meet the requirements of sanitary standards for emissions into the atmosphere. Tubular cloth filter of dry-cleaning devices is subject to intense abrasive wear of the iron ore dust captured, which leads to a violation of sanitary standards for emissions of solid particles into the atmosphere. The results of pilot plant tests of a ceramic filter installed in the existing aspiration system for loading iron ore concentrate into railway wagons are described. The aerodynamic resistance of the ceramic filter is determined, as well as its technical and economic indicators. It was found that when replacing the tubular cloth filter with a ceramic pulse filter, a decrease in the residual dust concentration from 72 to 4 mg/m3 was achieved. The efficiency of cleaning the aspiration flow in a ceramic filter is 17.8 times higher than this indicator in the existing tubular filter. The replacement of cloth filter elements with ceramic ones in the body of the existing filtration system of the aspiration system for loading iron ore pellets into railway cars will reduce the gross emissions of iron-containing dust into the atmosphere from 47 to 1.9 tons/year. When replacing cloth filter elements with ceramic ones, the total fee for the negative impact on the environment within and above the MPE will decrease from 130 thousand roubles/year up to 85 thousand roubles/year. In addition, the return of dust material to production will save at least 0.5 million roubles/year.

Metallic Supported Pd-Ag Membranes for Simultaneous Ammonia Decomposition and H2 Separation in a Membrane Reactor: Experimental Proof of Concept

The use of ammonia as a hydrogen carrier requires efficient cracking technology. A promising solution is the use of a membrane reactor (MR), which enables both ammonia decomposition and hydrogen separation to take place within the same device, providing advantages in terms of efficiency and compactness compared to conventional systems. The literature reports that ceramic-supported double-skinned Pd-Ag membranes show outstanding performance for hydrogen separation as well as good stability of the separation layer during ammonia decomposition. However, their sealing in the reactor may result in leakage increase, while their mechanical stability remains an unresolved issue. To circumvent these limitations, the use of metallic supported Pd-based membranes is recommended, due to their higher mechanical stability and ease of sealing and integration in the reactor. In this work, we propose the development of robust metallic supported hydrogen-selective membranes for integration in membrane reactors for ammonia cracking. A conventional Pd-Ag membrane was prepared on a low-cost porous Hastelloy X tubular filter, modified with α-Al2O3/γ-Al2O3 to reach the desired surface quality. The membrane was then tested for ammonia decomposition in a MR configuration, showing the ability to reach >99% NH3 conversion above 475 °C with H2 feed recovery >60%. The results achieved pave the way towards a possible substitute for the ceramic-supported alternatives.

Development of the design and methodology for calculating the strength of a electrobaromembrane tubular apparatus

A tubular electrobaromembrane apparatus is developed for the separation of mixed technological solutions and wastewater, which simultaneously contain organic and inorganic substances. The design features of the device are gratings and end caps of a spherical shape, as well as tubular filter elements with the same filtration surface area while varying the diameter of different lengths. A method for calculating the strength of the body of the apparatus with the determination of the required thickness of the body wall and fiberglass end caps is proposed. Keywords: electrobaromembrane apparatus, separation, membrane, calculation, strength. mig@tstu.ru, spektr-tambov@yandex.ru

Enhancement of Cryo-EM maps by a multiscale tubular filter.

We present an approach to enhance cryo-electron microscopy (cryo-EM) postprocessed maps based on a multiscale tubular filter. The method determines a tubularness measure locally by the analysis of the eigenvalues of the Hessian matrix. This information is used to enhance elongated local structures and to attenuate blob-like and plate-like structures. The approach, thus, introduces a priori information in the reconstructions to improve their interpretability and analysis at high-resolution. The proposed method has been tested with simulated and real cryo-EM maps including recent reconstructions of the SARS-CoV-2. Our results show that our methods can improve obtained reconstructions.

In situ solvent recovery by using hydrophobic/oleophilic filter during wet lipid extraction from microalgae

While lipid extraction from wet microalgae has attracted attention as an economical method for microalgal biofuel production, few studies have focused the actual separation of extract phase from the emulsified extraction mixture. Here, a novel approach which utilizes hydrophobic/oleophilic filter was developed for the efficient solvent recovery. The filter was surface-modified by coating a functional polymer via initiated vapor deposition for the selective solvent permeability. While acid-treated Chlorella sorokiniana HS1 and n-hexane was stirred for lipid extraction, tubular filter module was immersed into the mixture for separation. The mixture was kept stirred during the separation to inhibit the buildup of cell debris on the filter by inducing crossflow on the filter. Extract phase was separated directly from the raffinate phase with high separation efficiency (> 98.3%) while maintaining permeation flux. The place-, space- and energy-efficient strategy reported here could be a useful tool for the solvent extraction process.

Design and Fabrication of a Portable Tubular Filter Pipe for Borehole Water Purification Systems

Two main sources of water (the surface water and underground water) were briefly discussed in this paper. Filtration which is a very significant treatment process for both surface water and underground water was also discussed. A portable tubular filter pipe for borehole water purification system was designed and fabricated. The materials used in the portable tubular filter pipe (sand layer depth of 0.15m of size 0.8 – 2mm and coarse gravel layer depth of 0.02m of size 5-8mm) were sourced locally. The coarse aggregate (gravel) layer served as support and distribution of water while the sand layer served as the filter medium. The diameter of the portable tubular filter pipe was assumed to take 4 inches PVC diameter pipe (0.1016m). The design reveals that the filter area is 0.0479m2, the flowrate in the filter is 8 x 10-5m3/s, the filter volume is 0.02m3 and the headloss in the filter is 0.5m. Materials used for the fabrication of the portable tubular filter pipe are PVC materials that are easily available in water treatment stores. Tests were carried with the fabricated portable tubular filter pipe on borehole water. The results show that the portable tubular filter pipe performed relatively well in purifying borehole water.

Improving the performance of silica-based crossflow membranes by surface crystallization for treatment of oily wastewater

Today, hundreds of billions of barrels of oily wastewater is generated per day by a wide range of industrial applications. Depending on its hazardous nature, it is not possible to reuse or discharge the wastewater without any treatment. This study exhibits the fabrication of a ceramic filter, which is designed to obtain high recovery with high filtrate rate during the treatment of oily wastewaters. Tubular type ceramic filter was fabricated using an extrusion technique from local silica source, glass waste, and some organic additives. The length of the ceramic filter is 200 mm where the outer diameter and wall thickness are 12 and 3 mm, respectively. Dried samples were sintered at a temperature of 900, 950, and 1000 °C for 1 and 3 h of time, respectively. The effects of sintering conditions on the crystalline phase pore size and distribution, porosity, and permeability is discussed. The fabricated filters have high corrosion resistance for acidic (pH = 1.5) and basic (pH=13) conditions (<1% mass loss in both acid and basic media). The filtration performances of the ceramic filters are investigated by crossflow microfiltration via transmembrane pressure of 0.5–1 bar for synthetic oily wastewater. The relatively coarse pore size of the ceramic filter produced than the alternatives of the literature, achieves the oil separation efficiency rate up to 99.75%, which is attributed to the surface properties of the produced filter where the surfaces are negatively charged. According to the results, it could be said that the fabricated ceramic filter has high potential for microfiltration applications (oil level of the filtrate obtained is as less as 2 mg/L) and can be used as a support for ultrafiltration and nanofiltration technologies.

Mathematical modeling of filtering process of two-phase suspensions in tubular filters under nonisothermal conditions

The hydrodynamic conditions in tubular filter cells operating under nonisothermal conditions are studied. The equations of mechanics of heterogeneous media are used to describe the separation process of two-phase suspensions, which are written and simplified in the cylindrical coordinate system taking into account characteristics of the flow. The challenge is solved semi-analytically. Using the methods of surfaces of equal consumptions and Slezkin, numerical calculations on the constructed mathematical model are presented for particular implementations of the separation process.

High‐performance suspended stripline wideband bandpass filter with new miniaturisation technology

A simple wideband tubular suspended stripline (SSL) bandpass filter using novel miniaturisation technology is presented. In this design, the equivalent circuit of the proposed filter is considered as the conventional tubular bandpass filter circuit. A new miniaturisation technology called ‘different height of cavity’ is applied to the filter design. A SSL filter is designed and fabricated with the passband from 0.6 to 1 GHz. The insertion loss is better than 0.6 dB in the passband while the return loss is mostly higher than 20 dB. The group delay variation is <0.2 ns. Good agreement between the simulated and measured result is observed, which proves the validity of the technique.

Simultaneous C and N removal from saline salmon effluents in filter reactors comprising anoxic-anaerobic-aerobic processes: Effect of recycle ratio

Salmon processing generates saline effluents with high protein load. To treat these effluents, three compact tubular filter reactors were installed and an integrated anoxic/anaerobic/aerobic process was developed with recycling flow from the reactor's exit to the inlet stream in order to save organic matter (OM) for denitrification. The reactors were aerated in the upper section with recycle ratios (RR) of 0, 2, and 10, respectively, at 30°C. A tubular reactor behave as a plug flow reactor when RR = 0, and as a mixed flow reactor when recycle increases, thus, different RR values were used to evaluate how it affects the product distribution and the global performance. Diluted salmon process effluent was prepared as substrate. Using loads of 1.0 kg COD m−3d−1 and 0.15 kg total Kjeldahl nitrogen (TKN) m−3d−1 at HRT of 2 d, 100% removal efficiencies for nitrite and nitrate were achieved in the anoxic-denitrifying section without effect of the dissolved oxygen in the recycled flow on denitrification. Removals >98% for total organic carbon (TOC) was achieved in the three reactors. The RR had no effect on the TOC removal; nevertheless a higher efficiency in total nitrogen removal in the reactor with the highest recycle ratio was observed: 94.3% for RR = 10 and 46.6% for RR = 2. Results showed that the proposed layout with an alternative distribution in a compact reactor can efficiently treat high organic carbon and nitrogen concentrations from a saline fish effluent with OM savings in denitrification.

Performance of photocatalytic membrane reactor with dual function of microfiltration and organics removal

A nano-structured TiO2 membrane having desired pore structure has been prepared by the anodization treatment of micro-porous tubular type pure titanium filter. The anodized nano-structured TiO2 membrane was found to act as photocatalyst and decompose N-nitrosodimethylamine (NDMA) efficiently under UV irradiation. This UV/anodized TiO2 membrane process realized the complete removal of NDMA with 20 mg L−1 concentration, indicating that this process can be a promising technology for the purification of NDMA contaminated water.

Mathematical simulation of the process of fine cleaning of suspensions

A mathematical model is considered of the process of interaction of filtrate within a pipe with a two-phase disperse mixture in the porous wall and outside of the pipe. The results of numerical solution of conjugate problem of heat and mass transfer demonstrate the advisability of preheating the substrate of a tubular filter for producing filtrate.

Design of Tubular Filter Based on Curve-Fitting Method

A design method of tubular filter based on S-parameter curve-fitting method is presented, and a synthesis process from low-pass prototype to tubular band-pass filter is also analyzed. By using step-increasing theory, the curve-fitting process for designing tubular filter is proposed in particular. This method not only makes sure that the values of serial elements are accurate in each simulated process, but also reduces the factors which influence the values of shunted elements, and decreases the complexity in determining the element size.

高温集塵用セラミックフィルタの熱衝撃時の温度・熱応力解析

A thermal cyclic fatigue testing method for a hot gas tubular filter proposed by Matsushima, et al. simulates the stress state in the filter during reverse pulse cleaning by blowing air. The filter is composed of two layers, one is a thick inner layer made of silicon carbide with coarse pores and the other is a thin outer layer made of mullite with fine pores. In this paper, we presented a new technique for analyzing temperature distributions in a filter in cold blowing air on the assumption that a Biot number could express a heat loss inside the filter caused by blowing air. Temperature and stress distributions in the filter were analyzed numerically on condition that the filter was exposed to high temperature flue gas and received thermal shock by cyclic blowing air. Residual stresses after sintering were also analyzed. The results revealed that the stresses were greatly affected by the thickness of the mullite layer, there were considerable tensile residual stresses in the mullite layer, and the thicker layer of silicon carbide had higher thermal shock stresses on the inner surface of the filter.

Flux enhancement in microfiltration by corkscrew vortices formed in helical flow passages

The performance of helical inserts in existing tubular filters has been investigated by Bellhouse et al. [12]. The insert and filter combination was found to deliver high filtration fluxes at low cross-flow rates over a wide range of applications, covering reverse osmosis to microfiltration. In addition the flow shear stresses were viscous, and fluids containing delicate organisms, such as marine algae, were concentrated without damage. The increased fluxes were attributed to the generation of corkscrew vortices, formed by the interaction of Dean vortices and an axial flow component. If this explanation is correct, it should be possible to generate similar corkscrew vortices in internal helical passages, which surround a central lumen. By coating the internal surface of the helical passages with a suitable membrane, a one-piece filter, capable of emulating the performance of the insert and tubular filter, could be constructed. Ruiz et al. [16] had demonstrated their ability to produce ceramic filters with internal helical grooves, and the Laboratoire des Materiaux et Procedes Membranaires at Montpellier University produced a number of prototype filters to a design derived from the geometries used in [12]. These filters were tested using high concentrations of bakers’ yeast. Similar fluxes to those obtained with the inserts and tubular filters were achieved, over the same range of flow rates. Whilst the mechanism of concentration polarisation reduction by corkscrew vortices works over the whole range of filtration applications, the unique combination of viscous flow, high fluxes, low cross-flow rates and high feed concentrations is particularly suited to microfiltration in bio-processing applications.

The reactivity of V2O5-WO3-TiO2 catalyst supported on a ceramic filter candle for selective reduction of NO

For realizing the environmental issues and constituting an economical treatment system, a catalytic filter based on V2O5/TiO2 supported on tubular filter elements has many advantages by removing NOx and particulate simultaneously from flue gas. In order to improve the activity of a catalytic filter based on V2O5/TiO2 supported on a commercial high temperature filter element (PRD-66), the promoting effects of WO3 were investigated in an experimental unit. PRD-66 presented very good properties for SCR catalyst carrier since it contains much active material such as A12O3 SiO{om2}, and MgO whose contributions were remarkable. For additional catalyst carrier, TiO2 particles were coated in the pores of PRD-66 with relatively good distribution of the particle size less than 1 μm, by a coating process applying centrifugal force. WO3, in the V2O5-WO3-TiO2/PRD-66 catalytic filter system, increased the SCR activity significantly and broadened the optimum temperature window. The catalytic filter shows the maximum NO conversion of more than 95% for NO concentration of 700 ppmv at face velocity of 0.02 m/sec, which is comparable to the current commercial catalytic filters of plate form.

The dewatering of a mining sludge containing hexavalent chromium using a tubular filter press - a South African development

A chromium smelting process can result, under oxidising conditions, in the production of a dust which when slurried and pumped to a waste dump heap is likely to pollute the environment. South Africa is a large producer of chromium metal and the problem of the release of hexavalent chromium (Cr6+) to the environment is a serious concern. The department of Water Affairs and Forestry in South Africa monitors all environmental discharges and regulate the levels of toxic chemicals and pollutants. The ‘Tubular Filter Press’ a South African developed sludge dewatering system was proposed for the recovery of dust in this effluent. The filter press was operated for the dewatering of waterworks sludges and promises to be successful for this application. A single tube pilot study shows that chromium discharge to the environment can be eliminated. Feed solids concentrations of between 40 and 50 g/l were fed to the tubular filter resulting in cake solids concentrations in excess of 50%. The operating pressure of the system was between 200 and 300 kPa and the flux reduced to 200 L/m2.h during the filtration cycle. The filtration was modelled using a variable pressure, internal cylindrical compressible cake filtration model and operating parameters for a full scale plant were proposed.

Pressure-Dependent Permeate Flux in Ultra- and Microfiltration

The effect of applied pressure on the permeate flux in cross-flow ultrafiltration (UF) and microfiltration (MF) was investigated both theoretically and experimentally. In UF and MF processes, the permeate fluxes are controlled by concentration polarization and cake formation over the membrane surface. As a better understanding of concentration polarization and cake formation becomes available, the permeate flux under any pressure can be theoretically predicted. Experiments were conducted in a ceramic tubular cross-flow filter with silica colloids of a narrow size distribution (model colloids). The pressure-dependent flux of the model colloidal suspension in cross-flow filtration was investigated under various experimental conditions. The experimental measurements were compared with the theoretical predictions, and the results showed that the pressure-dependent permeate flux in cross-flow filtration can be adequately predicted. Furthermore, theory and experiments demonstrated that the performance and opera...

Grimethorpe filter element performance—the final analysis

A demonstration hot gas filter, funded by the Electric Power Research Institute and installed in a pressurised fluidised bed combustor at Grimethorpe, South Yorkshire, UK was operated for a second period in 1991–92 for the Grimethorpe Topping Cycle Project (GTCP). This project was aimed at assessing the feasibility of running a gas turbine on coal-derived gas as part of the development programme for the Air Blown Gasification Cycle (formerly known as the British Coal Topping Cycle).As in previous studies operation of the filter led to progressive changes to the mechanical properties of the tubular clay-bonded silicon carbide filter elements. In order to explain the mechanisms behind these changes and thus determine operating conditions which influence element properties and performance detailed element characterisation and microstructural studies have been carried out. It has been found that slow bond devitrification and the development of a bond-grit interlayer of cristobalite led to changes in the integrity of the interface, with loss of strength and elastic modulus and a decrease in ultrasonic pulse velocity through the material. Microstructural studies suggest that the combination of the upper temperature of operation (≈ 830°C) and the thermal cycling during reverse pulse cleaning to remove the dust cake results in microcracking. While the strength losses experienced did not result in in-plant element failures, the reliability of the elements would be improved if operation can be limited to a temperature at which devitrification of the element's bond material is minimised.

Tubular filter with membrane technology for filter/thickener

In what is claimed to be a new combination of proven filter design and advanced membrane technology from two leading companies in their fields, this article describes a low-cost solution ideal for effluent treatment or product recovery applications that has been launched in the UK