Bag Filter Research Articles

Thermally stabilized polyacrylonitrile/polyphenylene sulfide composite membranes for efficient emission control in harsh environments

In harsh and complex environments, the emission of polluted air poses significant challenges to traditional filtration systems. In contrast to conventional approaches which primarily involve the incorporation of antioxidants into filter materials, this study introduces a novel methodology. Here, we employed polyacrylonitrile (PAN) as a coating for polyphenylene sulfide (PPS) fibers. Furthermore, we innovatively utilized a needle punching process in conjunction with segmented heat treatment to manufacture PAN-PPS composite filter membranes capable of withstanding extreme environmental conditions. During the segmented heat treatment process, the molecular structure of PAN coating underwent a series of changes, ultimately transforming into a heat-resistant ring trapezoidal structure, providing protection for PPS fibers that are prone to oxidation, and thereby enhancing the structural stability of composite filter membrane. Experimental results demonstrated a significant improvement in the mechanical properties of PAN-PPS composite fabric after segmented heat treatment, with the tensile strength increasing by 71.7 % and the Young’s modulus by 91.6 %. Additionally, the flame retardancy and hydrophobic properties of composite membranes were significantly enhanced, exhibiting the excellent stability and better filtration performance in extreme environments. This approach not only addresses the challenges posed by incorporating nano antioxidants into the spinning process but also significantly enhances the high-temperature resistance of the materials. This enables PAN-PPS composite filter bags to effectively control the emission of polluted gases in extreme environments. Furthermore, the thermal treatment process of the PAN coating is easy to implement and cost-effective, providing a novel strategy for the development of extremely high-temperature resistant filtering materials. This makes it possible to explore the development of flexible, high-performance air filtering materials for extreme environments in the future.

Research and application of bag filter system for railway ballast bed coal suction vehicles: An optimization and application study.

The current bag filter system used by railway ballast bed coal suction vehicles for cleaning coal dust from railway tunnels has low operational efficiency and generates significant volumes of dust. This paper describes a simulation test unit designed to enhance the dust removal performance in railway tunnels. The flow field inside the simulation test unit is investigated under different operating conditions through numerical simulations, and the variations in air volume and working resistance, total dust collection efficiency, and optimal operating parameters of a pulse cleaning system are identified through a series of experiments. The numerical results show that the pulse cleaning system does not significantly affect the uniformity of the flow field distribution at the bottom of the filter cartridge during the process of operation. The experimental research indicates that the simulation test unit satisfies the design requirements, achieving an average total dust removal efficiency of 99.93%. A field application shows that the total dust mass concentration at the operator position can be reduced from 335.8 mg∙m-3 to 4.2 mg∙m-3, effectively improving the operating environment within the tunnel.

The relationship between the resistance characteristics and structural parameters of the elongated filter cartridge in the dust collector

Due to the advantages of a large filtration area, elongated filter cartridges are gradually replacing filter bags in dust collectors. However, the production standards for these filter cartridges lack clarity in determining various parameters. Therefore, this paper combines experimental validation with computational fluid dynamics simulations to analyze the resistance characteristics of elongated filter cartridges, aiming to establish recommended parameter combinations for their optimal design. Single factor analysis and Response Surface Methodology (RSM) are employed for parameter optimization. The study establishes a quadratic regression model to predict resistance based on various filter cartridge parameters. Single factor analysis indicates that the optimal combination of length and pleat number is approximately diagonally distributed. The RSM ranks the factors' impacts on resistance as follows: length (L) > pleat number (N) ≈ pleat length (Pl) > filtering velocity (vf) > outer radius (R). The optimal parameter combination under global optimization is: N = 43, Pl=23 mm, R = 76 mm, L = 2 m. Additionally, the study analyzes the distribution of normal and tangential velocities of airflow on the filter medium surface to understand their impact on filter lifespan. Results indicate that tangential velocity has a significant impact on filter wear, and locations with higher tangential velocity are situated in the bottom region of the fold at the outlet.

Design and evaluation of a municipal solid waste incineration power plant integrating with absorption heat pump

The absorption heat pump can consume a small amount of high temperature heat source instead of electricity to realize the waste heat recovery. It has a potential to be applied in the energy efficiency improvement of municipal solid waste incineration power plant. In this study, a proposed integrated system has been designed, where the sludge heat pump drying system and dump pit heating system are coupled with the absorption heat pumps. The power generation improvement is evaluated through simulation calculation by EBSILON Professional and Aspen Plus. The results show that the power generation of proposed integrated system is 1.21 MW higher than that of reference power plant in winter operating condition. This is mainly due to the reductions of energy loss and exergy loss in incinerator and boiler system according to the energy flow and exergy flow analysis. The extracted steam from turbine is more suitable than the flue gas out of bag filter as the high temperature heat source of heat pump. In addition, the variable operating condition analysis is carried out for the proposed integrated system.

Biosorptive removal of fluoride from wastewater using tea domestic waste biochar

AbstractThe biochar of tea domestic waste was applied to eliminate F− from their aqueous artificial solutions and real contaminated wastewater. Pre-pyrolysis chemical activation method was used to synthesize biochar from tea domestic waste. Two modification methods were applied, acidic modification using H3PO4 (H-modified form) and basic modification using NaOH (OH-modified form). The synthesized forms of tea biochars were characterized by the determination of ash content, bulk density, Brunauer–Emmett–Teller analyses to detect the pore size, specific surface area, and pore volume, Elemental analyses to detect C, H, O, and N contents, Thermogravimetric analyses to detect the thermal behavior of biochars, and Fourier Transform Infrared analyses to detect the functional active groups of biochars. The synthesized forms of tea biochars were optimized for fluoride removal from aqueous solutions via filter bags method and applied in enhancement of the quality of wastewater from the factories of the new Borg El-Arab City, Egypt. The highest biosorption efficacy achieved was 109.18 mg F−/g biochar using the H-modified form under the optimum conditions of biochar dosage: pH: 2, 0.25 g/l, temperature: 50 °C, initial concentration of F−: 500 mg/l, exposure time: 30 min, and agitation rate: 300 rpm. The OH-modified form achieved less than half biosorption efficacy which reached 49.39 mg F−/g biochar. The existence of competitive anions in the solution had a negative influence on F− biosorption efficacy, where the impact followed the order of PO43− > SO42− > Cl− > NO3− > HCO3−. The H-modified tea biochar proved to be a promising biosorbent for industrial wastewater treatment by achieving removal efficacy ranges of 80.89–93.31% and returning all violated F− concentrations to the allowable limit. Sustainable development can be greatly supported by using domestic tea wastes in the removal of F− due to the dual disposal of waste and contaminants at the same time. The tea wastes are eco-safe and cheap biosorbent material can be utilized as a precursor for an efficacious tool for the elimination of F− from artificial solutions in addition to real wastewater.

Influence of Aging Time on Filtration Performance of P84 Filter Media with Seam.

Although the area with the seam is approximately 4% of the total area of an industrial filter bag, a more extensive investigation of the influence of this region on surface filtration is necessary since the small seam holes can be a conduit for the passage of fine particles even after a certain time of use of the filter bag. Therefore, this work aimed to assess the influence of aging time on the filtration performance of P84 filter bags (samples without and with seam) used in an industrial bag filter, regarding tensile mechanical properties, air permeability, fractional separation efficiency, and filtration cycles. The particulate matter applied (sinter dust) to evaluate the efficiency and to perform the cycles was collected in the hoppers of an industrial bag filter installed in the primary dedusting system of a sinter plant in the steel industry. The results showed that the filter bag aged for 10 months presented a fractional separation efficiency of almost 100%, even for the samples with a seam, suggesting that the seam holes were sealed by the powder in the industrial installation. As for the tensile mechanical properties, the tests showed that the aging of the filter bag caused a reduction in the tensile strength of the filter medium. With respect to air permeability and filtration cycles, the longer the aging time of the filter bag, the more similar was the filtration performance of the samples without and with seam.

Reducing microplastics in tea infusions released from filter bags by pre-washing method: Quantitative evidences based on Raman imaging and Py-GC/MS

Microplastics released from plastic-based filter bags during tea brewing have attracted widespread attention. Laser confocal micro-Raman and direct classical least squares were used to identify and estimate micron-sized microplastics. Characteristic peaks from pyrolysis-gas chromatography/mass spectrometry of polyethylene terephthalate, polypropylene, and nylon 6 were selected to construct curves for quantification submicron-sized microplastics. The results showed that microplastics released from tea bags in the tea infusions ranged from 80 to 1288 pieces (micron-sized) and 0 to 63.755 μg (submicron-sized) per filter bag. Nylon 6 woven tea bags released far fewer microplastics than nonwoven filter bags. In particular, a simple strategy of three pre-washes with room temperature water significantly reduced microplastic residues with removal rates of 76 %–94 % (micron-sized) and 80 %–87 % (submicron-sized), respectively. The developed assay can be used for the quantitative evaluation of microplastics in tea infusions, and the pre-washing reduced the risk of human exposure to microplastics during tea consumption.

A Pattern Recognition Method for Filter Bags in Bag Dust Collectors Based on Φ-Optical Time-Domain Reflectometry

The use of phase-sensitive optical time-domain reflectometry (Φ-OTDR)-distributed fiber vibration sensors to detect and identify damaged bags in bag dust collectors has the potential to overcome the inadequacy of traditional damaged bag detection methods. In our previous study, we verified the feasibility of applying this technique in the field of damaged bag detection in bag filters. However, many problems still occur in engineering applications when using this technology to detect and identify damaged filter bags in pulse-jet dust-cleaning bag dust collectors. Further studies are needed to characterize the fiber vibration signals inside different types of rectangular damaged filter bags. A filter bag damage identification and detection method based on empirical mode decomposition (EMD) and a backpropagation (BP) neural network is proposed. The signal feature differences between intact filter bags and damaged filter bags with different rectangular hole sizes and positions are comparatively analyzed, and optimal feature difference parameters are proposed. Support vector machine (SVM) and a BP neural network are used to recognize different types of filter bag signals, and the comparison results show that the BP neural network algorithm is better at recognizing different types of filter bags, obtaining the highest recognition rate of 97.3%.

Hybrid electrostatic filtration systems for exhaust gas cleaning

Emission of submicron and nanoparticles by industrial processes, like coal or biomass combustion, solid waste incineration, cement kiln heating, and glass production is a serious environmental problem. The application of most effective bag filters is limited due to very high temperature of the exhaust gases from most of these processes, sometimes >1000 K, which the filter material cannot resists. Cyclones, which could be resistant to these temperatures, are not effective for PM2.5 particles removal, which are the most abundant in these processes. Electrostatic precipitators remove dust from flue gases with high mass collection efficiency, but in submicron range (~100 nm to 1 μm) the so called “penetration window” occurs, in which the fractional collection efficiency decreases even below 50% at minimum. Hybrid electrostatic filtration systems, which combines various conventional gas-cleaning devices were therefore proposed and tested in several research papers, in order to improve the overall collection efficiency of the precipitation processes. The heart in all of these devices is an electrostatic particle charger, which can be a conventional electrostatic precipitator, a corona-discharge particle precharger, or electrostatic particle agglomerator. After charging and/or agglomeration, the particles can be further removed by other devices like cyclones, electrostatic precipitators, or bag filters (after gas cooling to an allowable temperature). The paper reviews specific problems encountered in exhaust gas cleaning from various industrial processes, and the most interesting constructions designed for this goal. In particular, an example of a system comprising a unipolar electrostatic agglomerator, which simultaneously charges the particles and agglomerates them in alternating electric field, for the formation of aggregates of finer particles (PM1) with larger species, which could be removed by any conventional gas cleaning device, with sufficiently high collection efficiency, has been discussed in details.

Investigations of the recycling of airbag filters from the cement industry into fabric/polymer or fabric/cement composite materials

The cement industry, an essential contributor to global infrastructure development, generates substantial amounts of airborne pollutants during cement production processes. Bag filters play a crucial role in mitigating these emissions by capturing particulate matter and improving air quality. However, conventional bag filters eventually wear out and need replacement, leading to a significant environmental burden from discarded filter materials. This study explores a sustainable approach to address this issue by investigating the potential of recycling used bag filters from the cement industry. The focus of the investigation is on fabric/polymer or fabric/cement composite materials, which exhibit promising properties for recycling applications. The research begins with an in-depth analysis of the discarded bag filters. This characterization enables the selection and optimization of suitable recycling processes for fabric/polymer or fabric/cement composites. Furthermore, the study evaluates the performance of recycled fabric/polymer or fabric/cement composites as alternatives to conventional methods of bag filters in cement recycling and mechanical parameters of the airbag filter when used as reinforcement in the polyester matrix or cementitious composites. In conclusion, recycling bag filters of the cement industry in fabric/polymer or fabric/cement composite materials offers a promising avenue for reducing waste generation and enhancing resource efficiency. The study underscores the importance of transitioning towards circular economy principles in industrial processes. Recycling bag filters in the cement industry is a sustainable approach that supports environmental responsibility and contributes to the circular economy. It helps conserve resources, reduce waste, and minimize industry’s impact on the environment.

Study of the effectiveness of using a fine wastewater treatment plant at petrochemical production enterprises

The problem of treatment and neutralization of wastewater from chemical, petrochemical and oil refining industries is associated with the removing from them of suspended solid and plastic particles of pollution of various chemical natures, oil and petroleum products, heavy metals, surfactants, acids, alkalis, phenols and other harmful substances. To effectively treat water, various filters are used, which differ in parameters and characteristics. The purpose of this work is to determine the possibility of replacing cartridge filters used at PetroKazakhstan Oil Products LLP with easily regenerable bag filters. In the course of the research, it was found that the use of cartridge and bag filters contributes to more effective water treatment, in particular, from suspended sub- stances. When comparing them, we can say that the latter is advantageous in that it does not need to be changed when clogged, like a cartridge filter, but simply rinsed and used again in the technological chain. The bag element is quite simply washed in water, but if it is heavily clogged, it can be washed either in a solution of citric acid (20 g/l) or in an alkali solution (10 g/l).

Emission characteristics and removal of heavy metals in flue gas: a case study in waste incineration and coal-fired power plants.

Heavy metal pollutants such as Hg, As, Pb, Cr, and Cd emitted from coal and waste combustion have received widespread attention. In this study, we systematically investigated the emission characteristics of heavy metals in waste incineration and coal-fired flue gases, focused on testing the removal effect of self-made cold electrode electrostatic precipitator (CE-ESP) on heavy metals in flue gas, and made a comparative analysis with the existing air pollution control devices (APCDs). Test results from waste incineration power plant showed that each APCD showed a certain effect on the removal of heavy metals in condensable particulate matter (CPM), with an average removal efficiency of bag filter was 86%, but its effect on Hg removal was slightly worse. Under the coupled field with electrified cold electrode plate operation mode, the average removal efficiency of CE-ESP on heavy metals in CPM was as high as 93%, including 76% for Hg. The removal efficiency of heavy metals (especially Hg) in CPM increased with the increase of flue gas temperature difference between inlet and outlet of CE-ESP. Test results from this coal-fired power plant showed that heavy metals were enriched in fly ash to a higher degree than in slag, the synergistic control of heavy metals in submicron particulate matter by the dust remover was not obvious, and there was a significant correlation between each heavy metal emission factor and its content in coal. Under the temperature field with non-electric cold electrode plate operation mode, the overall effect of CE-ESP on the removal of gaseous heavy metals was better than that of particulate heavy metals. Under the conventional electric field operation mode, CE-ESP was less effective in removing particulate Cr and gaseous Hg0. Under the coupled field with electrified cold electrode plate operation mode, the average removal efficiencies of CE-ESP for particulate and gaseous heavy metals were 82.37% and 76.16%, respectively.

Fermentação ruminal de amostras de alimento incubadas em sacos de filtro feitos de diferentes tecidos ou dispersos no meio usando um sistema de produção de gás in vitro

ABSTRACT: The effect of different feed substrates incubated in filter bags [no bag (NB); Ankom® F57, 25 μm pore size (25AN); polyester, 45 μm pore size (45PB); polyester, 67 μm pore size (67PB) ] or dispersed in the medium on gas production, digestion and rumen fermentation was evaluated using an in vitro gas production system. Filter bags reduced (P < 0.01) gas production but increased (P < 0.01) the in vitro dry matter digestibility (45PB and 67PB). Additionally, the use of filter bags with smaller pore size, reduced total volatile fatty acid (P < 0.01), but had minimal effects on acetate, propionate, and butyrate concentration. Our research suggested that using filter bags with a pore size of 67 µ would reduce some negative effects of incubating feed substrate dispersed in the medium or in filter bags with smaller pore size. However, the use of bags with a larger pore size might allow the wash out of small feed particles with consequent overestimation of digestibility.

IMPROVEMENT OF THE CLEANING SYSTEM OF OIL GAS FLOWS USING AN AERODYNAMIC INSERT

Air pollution is becoming a problem due to inefficient technological processes that accompany the mechanical processing of solid materials in various industries, including metalworking and woodworking, coal enrichment, coal burning in thermal power plants, metallurgy and construction materials industries. The problem is relevant for cement factories, since some of them use outdated equipment. Fine dust in this context becomes particularly important because the particle size of this dust affects the quality and grade of the concrete produced. Given the specifics of cement production and the goals of our research, which are to effectively collect small particles, it is important to note that wet cement production methods are not the best solution. The ideal solution for the problem of cleaning dust and gas flows in the cement industry is the use of a two-stage dust collection system, which combines an advanced cyclone and a bag filter. The system's periodic shaking mechanism allows for effective capture and control of fine dust particles, ensuring high quality cement production and reducing environmental impact. The combination of a cyclone, an acoustic coalescer and a block of bag filters, which is equipped with a periodic cleaning mechanism, as well as the addition of a system for collecting fine dust using a collector funnel, will split the collected dust into two fractions: fine (a = 10−5 to 10−7m) and coarse (a > 10-4m). The first fraction can be used to produce high-quality cement of high cost in the cement industry. The second fraction returns to the main technological process at its finishing stage.

Study of the discharge rate of dust from asbestos production facilities into the atmosphere

Now slate in Kazakhstan is produced at two modern plants in Semey (Semipalatinsk Plant of Asbestos - cement Products LLP-the largest of the two) and Shymkent (Tectum Engineering LLP). Currently, Kazakhstan consumes about 5 million sheets of slate per year, of which last year Kazakh enterprises produced 2.5 million with plans to increase production. Previously, all this volume was imported from abroad. The most loyal consumers are the southern regions, where, due to the hot climate, people remember and know how to handle slate, knowing its properties. For comparison, in Uzbekistan, about 35 million sheets of slate are consumed per year. The production of construction and technical products based on asbestos is accompanied by the formation of a significant amount of asbestos dust. At the same time, the main contribution to atmospheric air pollution is made by dust emissions with particle sizes up to 10 microns. In the industry's established practice, cyclones and bag filters are the most widely used for dedusting emissions. Experience of operation of these devices shows that due to the nature of the physico-chemical properties of asbestos dust required collection efficiency is not achieved (most of the fine fraction with particle sizes less than 5 μm cyclones virtually trapped; bag filters clogged fibrous asbestos dust), resulting in the concentration of dust in the air on the border of the sanitary protection zone of the enterprise is 7-10 times higher than the standard MPC.

Machine Learning tool to prevent and control Bag Filter clogging

Filter clogging represents a crucial issue in industrial filtration systems, and it can lead to various problems, such as reduced filtration efficiency, increased maintenance costs, and potential production disruptions. This paper presents a Machine Learning (ML) integrated solution, developed using Python, within a digital environment system created using LabVIEW to prevent and control filter clogging. The primary objective is to optimize the monitoring, control, and maintenance of a Bag Filter pilot plant. The digital environment incorporates a data comparison tool that trigger a compressor for filter cleaning. A Machine Learning algorithm has been integrated into the digital environment, where a comparison within real data acquired and the predicted one were performed to validate the selected algorithms and evaluate the Data Comparison tool. This initial phase's outcomes were used to develop a control system using LabVIEW software. The software compares estimated pressure drop values, reflecting optimal working conditions, with directly recorded pressure drop values. If the difference exceeds 10% of the optimal pressure drop, the controller activates a compressed air cleaning system, removing excess dust from the filter sleeves using an air jet. Additionally, when the estimated and acquired values diverge consistently over a 60-minute period, a user warning is triggered for filter sleeve replacement. Several tests were conducted at different air inlet velocities to assess the error between acquired and predicted data. The results indicated that the ML algorithm's error distribution remained below 5% for approximately 80% of the cases.

Solar-driven water evaporation using a collaborative photothermal conversion material system based on carbonized waste polyphenylene sulfide and copper sulfide.

Recently, water resources have become scarce due to the growing global population and human impact on the environment, coupled with the effects of climate change. For solving the problem of global freshwater shortage and increasing the value of discarded polyphenylene sulfide (PPS) filter bags, in this study, balsa wood was used as the base of a photothermal solar evaporator, chitosan solution was used as the binder, and the main photothermal conversion materials used were polyphenylene sulfide (CP) carbide and copper sulfide. In order to create synergistic photothermal conversion materials, freeze-drying and in situ precipitation were used to deposit the photothermal conversion materials on top of the balsa wood. The prepared CP/CuS-wood evaporator has excellent water evaporation performance and light conversion capability, with a water evaporation rate of 2.68 kg m-2 h-1 and a photothermal conversion efficiency of 93.2% under simulated one solar intensity irradiation. In addition, the evaporator can effectively remove organic dyes such as methylene blue and methyl orange. The evaporator's durability and seawater desalination capability have also been confirmed through seawater desalination experiments and outdoor tests. Studies have shown that solar interface photothermal evaporators are a viable solution for desalination and wastewater treatment. This eco-friendly, economically viable and stable photothermal evaporator mentioned in this paper has pioneering features and will be a new paradigm for desalination and wastewater treatment.

State Feedback Control Promotes Transition Efficiency of Bag Filters

State Feedback Control Promotes Transition Efficiency of Bag Filters

Enhancing NO degradation in visible light through plasma-treated photocatalytic substrates featuring TiO<sub>2</sub>@g-C<sub>3</sub>N<sub>4</sub> Z-scheme structure

In this study, a novel approach is introduced involving grafting and dip coating on photocatalytic substrates to create a Z-Scheme structure of TiO<sub>2</sub>@g-C<sub>3</sub>N<sub>4</sub> (TC). The synthesized photocatalyst undergoes comprehensive characterization through techniques such as XRD, SEM, XPS, FTIR, Contact Angle Goniometer, and BET analysis. Two configurations, TC coated on PVDF membrane (TC-PVDF) and TC coated on Film (TC-Film), are evaluated for the photodegradation of NO<sub>x</sub> under visible light. Compared to the benchmark material TiO<sub>2</sub>, TC-PVDF nanoparticles demonstrate outstanding performance, boasting a specific surface area of 60.93 m<sup>2</sup>/g and minimal toxic NO<sub>2</sub> byproducts, with concentration as low as 3.54 ppb, constituting only 0.46% during NO<sub>x</sub> remediation. These nanoparticles exhibit remarkable stability, with less than a 10% decrease in efficiency after 5 cycles of visible light irradiation. Plasma treatment transforms TC-PVDF from superhydrophobic to hydrophilic, with a contact angle reduction from 124.7° to 0°. Notably, TC-PVDF shows substantial efficiency enhancements, reaching 84.04%. This study broadens insights into catalytic bag filters, providing practical implications for their use in NO<sub>x</sub> removal. It offers innovative solutions for air purification, addressing environmental challenges and advancing sustainable technologies.

A Study on Failure Rate, Reliability, and Collection Efficiency Trend of Bag Filters in a Cement Plant

This thesis presents a comprehensive study on the failure rate, reliability, and collection efficiency trends of bag filters in a cement plant over 15 years. Bag filters are vital pollution control equipment used in various industries, including cement plants, to maintain environmental compliance. Understanding their performance and failure patterns is crucial to ensure efficient and reliable operation while adhering to stringent pollution control standards. The research findings reveal that the failure rate trend of bag filters closely follows the bathtub curve, with an initial high failure rate, a period of lower failures, and a subsequent increase in failures as the equipment nears the end of its life cycle. Reliability trends align with Madhab's Hat curve, exhibiting higher reliability during the first 10 to 12 years of operation, followed by a decline in reliability. The collection efficiency of bag filters declines as the equipment ages, with the efficiency decreasing from 99.998% in the early years to 95.05% in the 15th year. This emphasizes the importance of maintenance and retrofitting for older dust collection equipment to maintain high collection efficiency. The study concludes that the typical life span of bag filters ranges from 10 to 15 years, after which major maintenance interventions are necessary to minimize failure rates. The research provides valuable insights for maintenance engineers, design engineers, and reliability engineers, enabling them to improve the performance of pollution control equipment, such as bag filters, reverse air bag houses (RABH), and electrostatic precipitators (ESP), to meet the pollution control standards set by regulatory authorities.