Efficient Particulate Removal Technology
The baghouse calculation is performed by specialists using established methodologies and tables that provide the necessary data and coefficients. The performance of the equipment depends on the correctness and accuracy of this process. Any error in this calculation can lead to component failure and reduced cleaning efficiency.
Before purchasing an air purification system, it is necessary to perform appropriate calculations. To do this, gather information about the operating conditions of the device: the temperature of the cleaned gas environment, the specifics of the production process, types of dust, and the sizes of contaminating particles. This data is used to compile a technical specification, based on which a dimensional drawing is developed.
Before purchasing an air purification system, it is necessary to perform appropriate calculations. To do this, gather information about the operating conditions of the device: the temperature of the cleaned gas environment, the specifics of the production process, types of dust, and the sizes of contaminating particles. This data is used to compile a technical specification, based on which a dimensional drawing is developed.
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Technological Calculation
The technological calculation of a baghouse filter involves determining the filter surface area, the hydraulic resistance of the equipment, and the dust collection efficiency for the selected type.
Step 1 — Filter Surface Area
F = L / (60×g)
where:
where:
- L is the volumetric flow rate of the exhaust in cubic meters per hour (m³/h);
- g is the specific gas load during filtration in cubic meters per square meter per minute (m³/(m²·min)).
Step 2 — Specific Gas Load
g = gₙ x C₁ x C₂ x C₃ x C₄ x C₅
gₙ is the normative specific load, which depends on the type of dust and its regenerative properties. It is determined from the table below:
gₙ is the normative specific load, which depends on the type of dust and its regenerative properties. It is determined from the table below:
C₁, C₂, C₃, C₄ and C₅ are empirical coefficients that account for the characteristics of filter element regeneration, the effect of dust concentration on gas load, the influence of particle size distribution in the gas, the effect of gas temperature, and the requirements for the quality of filtration, respectively.
Values of the coefficient C₁ accounting for the characteristics of filter element regeneration:
Values of the coefficient C₁ accounting for the characteristics of filter element regeneration:
* Lower values are used for bags made of dense fabric, while higher values are used for those made of fiberglass.
Values of the coefficient C₂, accounting for the influence of dust concentration Cᵢₙ in the exhaust:
Values of the coefficient C₂, accounting for the influence of dust concentration Cᵢₙ in the exhaust:
It affects the duration of the filtration cycle. As the concentration increases, the regeneration frequency rises, and the specific load should decrease.
Values of the coefficient C₃, accounting for the influence of particle size distribution in the gas:
Values of the coefficient C₃, accounting for the influence of particle size distribution in the gas:
Values of the coefficient C₄, accounting for the influence of the temperature of the cleaned gas:
Values of the coefficient C₅, accounting for the requirements for the quality of gas purification:
Step 3 — The hydraulic resistance
It consists of the resistance of the housing ΔPₕ and the resistance of the filtering surfaces ΔPₛ:
∆Р = ∆Pₕ + ∆Pₛ , Pa
The indicator is characterized by a constant component ΔP′ and a variable component ΔP′′:
ΔPₛ = ΔP′ + ΔP′′, Pa
The constant component is determined by the relationship:
ΔP′ = Kₚ x μ x Wf, Pa
where
Values of the coefficient Kₚ:
∆Р = ∆Pₕ + ∆Pₛ , Pa
The indicator is characterized by a constant component ΔP′ and a variable component ΔP′′:
ΔPₛ = ΔP′ + ΔP′′, Pa
The constant component is determined by the relationship:
ΔP′ = Kₚ x μ x Wf, Pa
where
- Kₚ – coefficient characterizing the resistance of the filter partition with a residual layer of dust, determined from the table:
Values of the coefficient Kₚ:
The coefficient Kₚ depends on the thickness and permeability of the filter partition, the amount of dust remaining on the partition after regeneration, and the properties of the dust. Therefore, this coefficient is determined experimentally.
μ — gas viscosity, Pa·s, determined from the table:
Dynamic Viscosity and Density of Dry Air
μ — gas viscosity, Pa·s, determined from the table:
Dynamic Viscosity and Density of Dry Air
- Wf — filtration velocity, m/s;
L — volumetric flow rate of cleaned gases, m³/h;
F — area of filtering elements, m².
The variable component of hydraulic resistance is
ΔP′′ = Kdr x μ x τ x Cᵢₙ x Wf² , Pa
where
- Kdr – is the coefficient of dust layer resistance, determined from the table:
- μ — gas viscosity, Pa·s
- τ — duration of the filtration cycle, seconds
h — height of the unit
It should be noted that the total resistance of baghouses should not exceed 2800 Pa, while the resistance of the dust layer on the partition should be 600 to 800 Pa.
Step 4 — The dust collection efficiency, accordingly, is:
η = ((Cin-Cfin) / Cin) ×100%
Step 5 — Amount of incoming dust:
Min = L × Cin , g/s
Step 6 — Amount of dust captured after filtration:
∆M = Min × η, g/s
Step 7 — Amount of dust released into the environment:
Mfin = Min - ∆M, g/s
To ensure proper ventilation and efficiency, it is important to accurately calculate baghouse CFM based on the airflow requirements and dust load of the system.
To ensure proper ventilation and efficiency, it is important to accurately calculate baghouse CFM based on the airflow requirements and dust load of the system.
Example
A baghouse calculation example typically involves several steps to determine key parameters like the filtration area, airflow (CFM), and pressure drop. Here's a basic outline:
Determine the gas flow rate (L, in cubic meters per hour or cubic feet per minute):
Example: 10,000 m³/h.
Calculate the filter area (F) based on the filtration velocity (v, m/min):
Example filtration velocity: 1 m/min.
Required filter area: F = L / v = 10,000 m³/h ÷ 60 (to convert hours to minutes) = 166.7 m².
Hydraulic resistance (∆P) is calculated based on filter type, gas temperature, and particulate properties.
This example helps estimate the necessary baghouse specifications to handle the airflow efficiently.
Determine the gas flow rate (L, in cubic meters per hour or cubic feet per minute):
Example: 10,000 m³/h.
Calculate the filter area (F) based on the filtration velocity (v, m/min):
Example filtration velocity: 1 m/min.
Required filter area: F = L / v = 10,000 m³/h ÷ 60 (to convert hours to minutes) = 166.7 m².
Hydraulic resistance (∆P) is calculated based on filter type, gas temperature, and particulate properties.
This example helps estimate the necessary baghouse specifications to handle the airflow efficiently.
Cost Estimate
A baghouse cost estimate involves key components:
- Equipment Costs: Includes the baghouse price, varying by size, capacity, and features, plus additional equipment like fans and ducts.
- Installation Costs: Covers labor, site prep, and necessary modifications, which can vary with installation complexity.
- Operational Costs: Encompasses energy use, maintenance (cleaning, filter replacements, repairs), and depends on system efficiency and air volume.
- Additional Costs: Includes permits, environmental compliance, and staff training.
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We always perform precise calculations and offer expert assistance in selecting the optimal dust collection or gas cleaning systems, typically completing this process within 1 to 2 days
Head of Engineering,
Vladimir Nikulin
Vladimir Nikulin
CALCULATION AND SELECTION
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