AERODYNAMIC RESISTANCE OF BASALT AND GLASS FIBER-BASED FABRICS USED IN BAGHOUSE FILTERS

ABSTRACT

This study investigates the application of basalt and glass fibre-based fabrics as filter media in baghouse filter systems used for cement dust removal. The aerodynamic resistance and cleaning efficiency of the filtration device were evaluated. Based on the mathematical processing of experimental results, the optimal parameters for the device and the filtration method were justified. During the experiments, the following variables were considered: gas flow rate ranging from 140 to 990 m³/h with an increment of 285 m³/h; gas velocity from 5 to 35 m/s with a step of 10 m/s; filter thickness (basalt and glass fibre) of 2, 3, and 4 mm; filter frame diameter of 140 mm. The particle size distribution of cement dust was: 1–5 µm – 23%, 5–20 µm – 16%, 20–43 µm – 38%, and 43–60 µm – 18%. The density of the dust-air mixture was 1.49 kg/m³. Experiments were conducted in laboratory conditions at a temperature of 150±2 °C.

АННОТАЦИЯ

В данной научной работе исследовано применение тканей на основе базальтового и стеклянного волокна в качестве фильтрующего материала в рукавных фильтрах, используемых для очистки цементной пыли. Оценено аэродинамическое сопротивление фильтров и их влияние на эффективность очистки. На основе математической обработки экспериментальных данных обоснованы оптимальные параметры конструкции и метода фильтрации. В ходе экспериментов варьировались следующие параметры: расход газа — от 140 до 990 м³/ч с шагом 285 м³/ч; скорость газа — от 5 до 35 м/с с шагом 10 м/с; толщина фильтров из базальтового и стекловолокна — 2, 3 и 4 мм; диаметр каркаса фильтра — 140 мм. Размеры частиц цементной пыли распределялись следующим образом: 1–5 мкм — 23 %, 5–20 мкм — 16 %, 20–43 мкм — 38 %, 43–60 мкм — 18 %. Плотность пылевоздушной смеси составляла 1,49 кг/м³. Все испытания проводились в лабораторных условиях при температуре 150±2 °C.

Keywords: basalt fibre, glass fibre, baghouse filter, aerodynamic resistance, resistance coefficient, gas velocity, density, cement dust, particle size.

Ключевые слова: базальтовое волокно, стекловолокно, рукавный фильтр, аэродинамическое сопротивление, коэффициент сопротивления, скорость газа, плотность, цементная пыль, диаметр частиц.

1. Introduction

In recent years, the rapid development of industrial sectors, coupled with increasing demands for quality and environmental sustainability, has led to a growing complexity in the physicochemical composition of emissions released during manufacturing processes [1, 2]. Particularly in the production of construction materials—such as cement manufacturing—dust-laden gas emissions pose significant threats to both the environment and human health [3].

Conventional dust and gas separation technologies, including gravitational, inertial, and centrifugal force-based separators (e.g., cyclones), often fail to effectively capture fine particulate matter, especially particles in the 1–20 µm range [4]. As a result, many existing filtration systems do not comply with modern Maximum Allowable Concentration (MAC) standards, necessitating the development and implementation of more efficient air purification solutions [5,6].

This study focuses on the application of baghouse filter systems used in cement production plants for the removal of airborne dust, emphasizing the aerodynamic resistance of filtering fabrics made from basalt and glass fibres. These materials are evaluated for their efficiency and potential to enhance filtration performance under industrial operating conditions.

2. Materials and methods

At the initial stage of the research, a systematic evaluation of potential fabric materials suitable for baghouse filter applications was conducted using the MATLAB software environment. The selection criteria were based on key performance indicators relevant to industrial dust filtration processes, including aerodynamic resistance, dust capture efficiency, thermal resistance, and service life [7, 8]. Each parameter was analyzed as a determining factor in assessing the fabric’s suitability for high-temperature and high-dust environments, particularly within cement production facilities.

To achieve a comprehensive understanding of material behaviour under operational loads, a review of existing scientific studies and experimental findings was performed. This included comparative analyses of filtering materials such as aramid, polyester, fibreglass, and basalt-based fabrics. The collected data were systematized and assessed through MATLAB-based simulations to determine their aerodynamic properties and filtration effectiveness under various air velocities and particle concentrations.

Based on the outcomes of this preliminary assessment and considering the advantages highlighted in the literature—such as high-temperature tolerance, mechanical stability, and fine particle retention capacity—a hybrid filtering fabric composed of basalt and glass fibres was developed for experimental testing [9,10]. This composite structure was chosen due to its favourable thermomechanical and filtration properties, particularly in capturing fine cement dust particles ranging from 1 to 60 microns.

The developed filter fabric was manufactured using a layered nonwoven technique to ensure uniform porosity and mechanical integrity across its surface. The physical appearance of the fabricated filter fabric sample is presented in Figure 1.

To compare alternative filtering materials, MATLAB-based simulations were conducted, and the performance characteristics of four fabric types were evaluated. The aerodynamic resistance of each material is graphically presented in Figure 2, and the detailed properties are summarized in Table 1.

Table 1.

Comparative Properties Of Filter Materials

To validate the simulation results under real-world conditions, laboratory-scale testing was carried out. The object of the study was the dust and gas emissions originating from the cement production plant operated by TURONEKOSEMENTGROUP LLC. In the laboratory, the proposed filter was installed in a custom-designed filtration unit that mimicked industrial conditions [11].

The experimental setup allowed control over critical variables such as gas flow rate (140–990 m³/h), gas velocity (5–35 m/s), and operating temperature (150±2°C). The general view of the experimental filtration system is shown in Figure 3.

Figure 3. Overview of the basalt fabric narrow filter experimental setup

The tests were conducted following international standards for air filtration materials, including ISO 16890 and EN 779, ensuring the accuracy and reproducibility of the results. Key performance indicators such as pressure drop, dust removal efficiency, and filter durability were measured to assess the effectiveness of the proposed material in real-time dust capture applications.

3. Results and discussion

3.1. Experimental Parameters and Test Conditions

During experimental investigations, several key variables were systematically altered to evaluate the performance of the developed filter media under dynamic operating conditions. These parameters included:

• Gas flow rate (Q_ҳ): 140–990 m³/h, increment ΔQ_ҳ = 285 m³/h
• Gas velocity (ω_gas): 5–35 m/s, increment Δ ω_gas = 10 m/s
• Filter thickness made based on basalt and fibreglass (δ_ф): 2 mm, 3 mm, 4 mm
• Filter frame diameter (d_ф.д): 140 mm
• Dust particle size distribution:

- 1–5 µm: 23%

- 5–20 µm: 16%

- 20–43 µm: 38%

- 43–60 µm: 18%

• Dust-air mixture density (ρ): 1.49 kg/m³
• Test temperature: 150 ± 2°C (laboratory conditions)

These settings replicate realistic cement industry emissions and allow for precise evaluation of filter performance under varying dust loads and flow dynamics.

3.2. Aerodynamic Resistance and Performance Evaluation

The aerodynamic behaviour of the filtering materials was analyzed through the pressure drop values and resistance coefficients. The resistance of the filter system increased proportionally with filter thickness. The total aerodynamic resistance coefficient (ζч.қ) was calculated as follows:

• For δф = 2 mm → ζч.қ = 2.4
• For δф = 3 mm → ζч.қ = 2.7
• For δф = 4 mm → ζч.қ = 3.2

These results indicate a trade-off between filtration efficiency and resistance: thicker fabrics increase retention capacity but also lead to higher pressure loss.

Filtering fabrics are generally characterized by their air permeability, which refers to the airflow rate per unit pressure drop (usually at ΔP = 50 Pa). The clean filter resistance (∆рт) under a typical load of 0.3–2 m³/(m²·min) was observed to vary between 5–40 N/m².

3.3. Dust Accumulation and Regeneration Dynamics

As dust accumulates within the filter structure, its hydraulic resistance increases, leading to a reduced gas flow. To maintain operational performance, periodic regeneration (e.g., reverse air pulses or mechanical shaking) is required.

Over multiple filtration-regeneration cycles, a residual dust equilibrium forms in the fabric, defined by two key components:

∆р_р – resistance from embedded dust after regeneration

∆_рп.с – resistance from dust deposited between regeneration cycles

The total resistance of the “fabric–captured dust” system is given by:

                                    (1)

Here:

∆Pр – total aerodynamic resistance of the filter after regeneration

∆Pр – experimentally determined equilibrium resistance

∆Pн.с – resistance from newly accumulated dust between regeneration cycles

For cement dust filters made from felt-type fabrics, the normalized residual resistance ∆рр/u typically ranges from 850 to 1100 (Pa)/(m/min).

3.4. Mathematical Modelling of Dust Layer Resistance

The aerodynamic resistance of the dust layer can also be modelled using the Kozeny–Carman equation, assuming laminar flow across porous media [12]:

                          (2)

Where:

q_П.С –  – dust mass deposited per m² between regeneration cycles (kg/m²)

р_Ч – dust particle density (kg/m³)

ε_ПС – porosity of the dust layer

r_П – average root-mean-square radius of particles (m)

Figure 4 illustrates the variation in porosity observed during experimental cycles.

Figure 4. Experimentally determined porosity values of the residual dust layer after multiple filtration–regeneration cycles

3.5. Relationship Between Resistance and Deposited Dust Layer Under Constant Filtration Velocity

The relationship between the amount of accumulated dust during multiple regeneration cycles at constant filtration velocity and the corresponding aerodynamic resistance ∆р_т.п./u was experimentally determined. This dependency, illustrated in Figure 4, is considered fundamental for characterizing the real operating conditions and service performance of the filtering fabric.

Assuming the resistance of the ‘fabric–dust sediment’ system increases linearly throughout the filtration cycle; the total pressure drop during filtration can be expressed as:

                              (3)

In practice, the resistance of the filter before regeneration ∆р_р./u does not significantly differ from the post-regeneration residual resistance. For instance, 1 kg of dust accumulated per 1 m² of filter surface generates approximately 1 Pa of aerodynamic resistance when the filtration gas velocity is u = 1 m/min. The proportional coefficient k_п.с. can be expressed as:

                         (4)

Here,  is the increase in resistance due to the accumulation of dust from ∆р'_р to ∆р'_тп.

The resistance of the dust layer is directly proportional to the square of the filtration velocity. For example, if the filtration velocity is doubled, the resistance generated by the dust layer increases by a factor of four during the same filtration period (τ).

Conclusion

During the operation of industrial filters used for cement dust collection, changes occur both within the dust layer and on the surface of the filtering fabric. Consequently, the dust penetration resistance of the filter media cannot be considered a constant value. It varies over time, depending on operational conditions such as particle size, airflow speed, and the accumulation of residual dust.

At present, it is not yet feasible to derive a general theoretical equation for predicting the performance of new fabric filters under varying conditions. Therefore, new research and development efforts rely heavily on empirical data gathered from currently operating filtration systems.

In this study, experimental and semi-industrial tests were conducted using filter fabrics made from basalt and glass fibres, materials which are widely used in modern dust collection systems due to their high-temperature resistance and mechanical strength. The data obtained from these tests provide valuable insights into the filtration dynamics, aerodynamic resistance behaviour, and overall efficiency of these advanced filter materials.

The results support the continued investigation and optimization of basalt- and glass-based fabrics for use in high-load cement dust filtration environments, and highlight the need for further studies to develop predictive models based on empirical resistance characteristics observed under actual operating conditions.

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