Standard Excel cannot loop adiabatic saturation easily. Write a simple VBA function:
Function AdiabaticSaturation(T_gas, RH_in, P_atm)
' Iterative loop to find T_out where heat lost = evaporation heat
Do While Abs(HeatBalance) > 0.01
T_out = T_out - 0.1 * (HeatBalance / Slope)
Loop
End Function
Why this is "Hot": This macro transforms a static calculator into a dynamic tool for variable flue gas temperatures.
Includes macro-enabled buttons for:
The gas will cool to the adiabatic saturation temperature (typically 40°C to 70°C depending on water temperature).
Equation:
m_gas * Cp_gas * (T_in - T_out) = m_water * λ
Where λ is the latent heat of vaporization of water.
When searching for "scrubber design calculation excel hot", do not settle for a static PDF or a generic absorber sheet. You require a dynamic workbook that solves the adiabatic cooling curve, corrects gas density, and checks thermal survival of droplets.
Checklist for your ideal Excel tool:
By mastering these calculations, you move from guesswork to precision engineering—ensuring your hot gas scrubber operates safely, efficiently, and without thermal failure.
Need a template? Look for downloadable workbooks that include VBA macros for iterative solving, as standard Excel formulas cannot handle the circular logic required for true hot gas adiabatic saturation.
Wet scrubber design requires precise calculations to ensure pollutant removal efficiency and operational safety. This guide breaks down the essential parameters for building a "hot" gas scrubber design spreadsheet in Excel, focusing on packed bed towers. Core Design Objectives
A high-temperature scrubber must cool the gas stream while removing particulates or acid gases. Your Excel tool should solve for these three primary variables: Column Diameter: Based on gas velocity and flooding limits.
Packing Height: Based on the Number of Transfer Units (NTU) and Height of a Transfer Unit (HTU).
Liquid-to-Gas (L/G) Ratio: To ensure adequate surface wetting and cooling. 1. Input Data & Gas Properties
Start your Excel sheet with an input section for the "hot" inlet conditions.
Inlet Gas Temperature: Typically 300°F to 1000°F+ for industrial vents.
Gas Flow Rate: Enter in ACFM (Actual Cubic Feet per Minute).
Contaminant Concentration: Inlet vs. required outlet (to calculate required efficiency).
Physical Constants: Use Excel formulas to calculate gas density at hot temperatures using the Ideal Gas Law ( 2. Saturation & Cooling Calculations
Before chemical scrubbing happens, hot gas must be "quenched" to its adiabatic saturation temperature.
Evaporative Cooling: Calculate the water required to cool the gas.
Volume Reduction: Note that as gas cools, its actual volume decreases significantly. Design your column diameter based on the volume at the average or outlet temperature to avoid over-sizing. 3. Column Diameter & Flooding
To prevent the liquid from being blown out of the top of the tower, you must calculate the flooding velocity. Packing Factor ( Fpcap F sub p
): Specific to your packing material (e.g., Raschig rings, Pall rings).
Eckert’s Generalized Pressure Drop Correlation: Program this formula into Excel to find the diameter at 50%–70% of the flooding velocity. Equation: 4. Calculating Packing Height
The "Height of the Tower" depends on how difficult the contaminant is to remove. NTU (Number of Transfer Units):
HTU (Height of a Transfer Unit): Typically ranges from 1.5 to 3.5 feet for most packings. Total Height:
Safety Factor: Always add 10%–20% to the calculated height in your Excel summary. 5. Pressure Drop Calculations
Calculating the pressure drop is vital for sizing the ID (Induced Draft) fan.
Dry vs. Wet Pressure Drop: Use the Leva equation or manufacturer-specific curves.
Target: Keep pressure drop between 0.5 and 1.0 inches of water column per foot of packing. Excel Setup Tips for Engineers
Dropdowns: Use Data Validation for packing types and materials (PVC, FRP, Stainless Steel). scrubber design calculation excel hot
Conditional Formatting: Highlight cells in red if the flooding percentage exceeds 80%.
Goal Seek: Use Excel’s "Goal Seek" feature to find the optimum L/G ratio for a target outlet concentration.
🚀 Pro Tip: When dealing with "hot" gases, ensure your material selection (FRP or alloys) is validated against the saturation temperature calculated in your sheet.
Scrubber Design Calculation using Excel
A scrubber is a type of air pollution control device that uses a liquid to remove contaminants and pollutants from gas streams. Designing a scrubber requires careful calculation of various parameters to ensure effective performance. Here's a step-by-step guide on how to perform scrubber design calculations using Excel:
Step 1: Define Design Parameters
Step 2: Calculate Scrubber Diameter
The scrubber diameter (D) can be calculated using the following formula:
D = √(4 * Qg / (π * Vg))
where Vg is the gas velocity (m/s or ft/s)
Assuming a typical gas velocity of 3-5 m/s, let's use 4 m/s for this example.
| | | | --- | --- | | Qg (m³/s) | 1 | | Vg (m/s) | 4 | | D (m) | =SQRT(4*1/(PI()*4)) | =0.89 m |
Step 3: Calculate Scrubber Height
The scrubber height (H) can be calculated using the following formula:
H = (L/D) * D
where L/D is the aspect ratio (typically 3-5)
Assuming an aspect ratio of 4, let's use L/D = 4 for this example.
| | | | --- | --- | | L/D | 4 | | D (m) | 0.89 | | H (m) | =4*0.89 | =3.56 m |
Step 4: Calculate Liquid-to-Gas Ratio (L/G)
The liquid-to-gas ratio (L/G) is a critical parameter in scrubber design. A higher L/G ratio typically results in better contaminant removal, but also increases the energy consumption.
L/G = Ql / Qg
| | | | --- | --- | | Ql (m³/s) | 0.01 | | Qg (m³/s) | 1 | | L/G | =0.01/1 | =0.01 |
Step 5: Calculate Contaminant Removal Efficiency
The contaminant removal efficiency (η) can be calculated using the following formula:
η = (C_in - C_out) / C_in
where C_in is the inlet contaminant concentration and C_out is the outlet contaminant concentration.
Assuming a target removal efficiency of 90%, let's use η = 0.9 for this example.
| | | | --- | --- | | C_in (ppm) | 100 | | η | 0.9 | | C_out (ppm) | =(1-0.9)*100 | =10 ppm |
Excel Template
Here's an example Excel template that you can use to perform scrubber design calculations:
| Parameter | Value | Unit | | --- | --- | --- | | Gas flow rate (Qg) | | m³/s | | Gas temperature (Tg) | | °C | | Gas pressure (Pg) | | Pa | | Liquid flow rate (Ql) | | m³/s | | Liquid temperature (Tl) | | °C | | Contaminant concentration (C) | | ppm | | Scrubber diameter (D) | | m | | Scrubber height (H) | | m | | Liquid-to-gas ratio (L/G) | | - | | Contaminant removal efficiency (η) | | - |
You can download a sample Excel template from [insert link].
Conclusion
Scrubber design calculations involve several steps, including defining design parameters, calculating scrubber diameter and height, determining liquid-to-gas ratio, and estimating contaminant removal efficiency. By using Excel templates, you can simplify these calculations and optimize your scrubber design. Remember to validate your results with experimental data or simulation models to ensure accurate performance.
🔥 Master Your Scrubber Design: Hot Gas Stream Excel Guide
Designing a scrubber for "hot" gas streams requires more than just standard absorption formulas. You must account for gas cooling, adiabatic saturation, and volume expansion. Use this structure to build a robust Excel calculator. 1. Core Inputs (The Essentials) Gas Stream Data: Inlet temperature ( Tincap T sub i n end-sub ), mass flow rate ( ṁgasm dot sub g a s end-sub ), and initial pollutant concentration ( Cincap C sub i n end-sub Target Efficiency: Desired removal percentage (e.g., 99%). Liquid-to-Gas (L/G) Ratio: Typically for wet systems. 2. Key Design Formulas for your Excel Cells Saturation Temperature ( Tsatcap T sub s a t end-sub
): The gas must be cooled before effective scrubbing. Calculate the adiabatic saturation temperature to determine the final volume. Scrubber Capacity:
Blower Capacity (per hour) = Total Air Flow Rate (m³) / Time. Removal Efficiency ( ): Excel Formula: =(Entry_Conc - Exit_Conc) / Entry_Conc. L/G Ratio: Use the Torch-Air standard of gallons per ft3f t cubed of air for high-performance units. 3. Pro-Tips for "Hot" Scrubber Sizing
Material Selection: Hot gas often requires exotic alloys or specialized FRP (Fiber Reinforced Plastic). Ensure your Excel includes a "Material Factor" lookup table.
Volume Expansion: Remember that hot gas occupies more volume (
). Your blower CFM must be sized for the actual temperature, not just standard conditions.
Water Evaporation: Calculate the water lost to evaporation to ensure your pump and hydro-tanks are sized correctly.
Looking for a pre-built template? Check out engineering resources like the Microsoft Support Guide for help with complex cell logic or Torch-Air's Engineering Blog for the full physics breakdown.
Wet Scrubber Design: Steps, Parameters, Calculation, Equations
This write-up covers the thermodynamic principles, the step-by-step calculation logic required for the Excel model, and the critical design parameters.
The design calculation spreadsheet provides a rapid iteration tool for sizing Venturi scrubbers. By linking throat velocity directly to pressure drop and efficiency curves, the engineer can optimize the system for the lowest operating cost (fan power) while meeting emission standards.
Recommendation for Excel Implementation:
Ensure the spreadsheet utilizes named ranges (e.g., Gas_Temp, Gas_Density) rather than cell references (e.g., B5). This minimizes errors during formula expansion and makes the "Solver" functionality more robust.
Designing a scrubber, specifically for "hot" or high-temperature gas streams, requires accounting for gas humidification and volume changes before sizing the vessel. You can find pre-built templates on platforms like Scribd or Cheresources that handle these calculations. Core Calculation Steps for Hot Gas Scrubbers
For high-temperature applications, the "hot" gas must be cooled to its adiabatic saturation temperature before or during the scrubbing process. Gas Inlet Properties: Define your inlet gas temperature ( Tincap T sub i n end-sub
), flow rate, and pressure. Hot gases have lower density, which significantly increases the required tower diameter.
Saturation & Humidity: Calculate the saturated gas flow rate. For example, a gas at 400°F may have a saturation temperature around 127°F, which changes the volumetric flow rate ( Qsatcap Q sub s a t end-sub ) used for sizing.
Liquid-to-Gas (L/G) Ratio: This is the most critical design parameter. For venturi scrubbers, typical ratios are 7–20 gallons per 1,000 cubic feet of gas.
Tower Diameter: Use the gas velocity and pressure drop to find the cross-sectional area. The diameter ( ) is typically calculated as Pressure Drop ( ΔPcap delta cap P
): For venturi types, use the Hesketh or Calvert equations to ensure the fan can handle the resistance. Recommended Excel Templates
Excel calculation sheet for rating of a spray tower scrubber
For an industrial "hot" scrubber design calculation in Excel, you need to structure your spreadsheet to handle gas cooling (quenching) mass transfer simultaneously
. High-temperature inlet gases require an initial saturation step to prevent damage to internal packing and to stabilize the absorption chemistry. Core Calculation Workflow
To design a functional packed bed scrubber for hot gases, follow these steps: Gas Saturation & Flow Correction Standard Excel cannot loop adiabatic saturation easily
Calculate the "Saturated Gas Flow Rate." Hot gases shrink significantly when cooled by the scrubbing liquid. Use the ideal gas law and psychrometric data to find the adiabatic saturation temperature.
cap Q sub s a t end-sub equals cap Q sub i n end-sub center dot open paren the fraction with numerator cap T sub s a t end-sub and denominator cap T sub i n end-sub end-fraction close paren center dot open paren the fraction with numerator cap P sub i n end-sub and denominator cap P sub s a t end-sub end-fraction close paren (Corrected for moisture addition). Column Diameter Sizing Determine the column diameter based on superficial gas velocity ). For most vertical scrubbers, is kept between to avoid flooding while maintaining contact time. Calculation: Mass Transfer & Packing Height Calculate the Height of a Transfer Unit (HTU) Height Equivalent to a Theoretical Plate (HETP) . For hot acid gases (like cap H cap C l
), Norton’s correlation or empirical mass transfer coefficients ( cap K sub cap G a end-sub
) are commonly used to find the required packing depth for your target removal efficiency. Standard Target: removal efficiency. Hydraulic Performance (Pressure Drop)
Calculate the pressure drop across the packing to size your fan. High-temperature applications often have higher liquid-to-gas ( ) ratios, which increases the pressure drop. Typical Limit: Design for of the flooding velocity. Excel Spreadsheet Structure
To get a highly accurate wet scrubber design calculation Excel sheet, you must account for thermal effects, evaporation, and gas expansion when handling hot gas streams.
Below is the complete step-by-step framework to build your own robust design spreadsheet in Excel. 📊 Core Spreadsheet Input Parameters
To begin your calculations, set up an Inputs Section in your Excel sheet with the following variables: Gas Properties: Inlet Gas Flow Rate ( Qg,incap Q sub g comma i n end-sub ) in or CFMcap C cap F cap M . Inlet Gas Temperature ( Tincap T sub i n end-sub ) in ∘Craised to the composed with power cap C . Gas Molecular Weight ( MWgcap M cap W sub g ). Liquid Properties: Scrubbing Liquid (usually water) Inlet Temperature ( TL,incap T sub cap L comma i n end-sub ). Liquid Density ( ρLrho sub cap L ). Pollutant Data: Inlet Concentration ( Cincap C sub i n end-sub ). Desired Outlet Concentration ( Coutcap C sub o u t end-sub ) or target efficiency. ⚙️ Step-by-Step Design Calculations
Use these sequential formulas to build out the active calculating cells in your Excel grid. 1. Hot Gas Quenching & Saturation
Hot gases will immediately evaporate a portion of the scrubbing liquid upon contact, cooling the gas to its adiabatic saturation temperature. Excel Goal: Calculate the saturated gas flow rate ( Qg,satcap Q sub g comma s a t end-sub ).
Concept: Use the ideal gas law to account for volume shrinkage due to cooling, balanced against volume increase from added water vapor. Formula Clue: 2. Tower Diameter (Flooding Velocity Method)
To prevent the liquid from being blown out of the top of the scrubber, you must calculate the tower's cross-sectional area based on the gas velocity. Action: Calculate the Flooding Gas Velocity ( Ufcap U sub f ) using the Sherwood-Lobo Correlation. Excel Formula:Set your operating velocity ( Uopcap U sub o p end-sub ) at 60% to 70% of the flooding velocity.
Tower Area (A)=Qg,satUopTower Area open paren cap A close paren equals the fraction with numerator cap Q sub g comma s a t end-sub and denominator cap U sub o p end-sub end-fraction
Diameter (D)=4×AπDiameter open paren cap D close paren equals the square root of the fraction with numerator 4 cross cap A and denominator pi end-fraction end-root 3. Packing Height (Mass Transfer)
This determines how tall your packed bed needs to be to achieve your removal efficiency. Formula:
HTU (Height of a Transfer Unit): Characterizes the mass transfer efficiency of your chosen packing material. NTU (Number of Transfer Units): for lean systems. 4. Liquid-to-Gas (L/G) Ratio
For effective particulate and acid gas removal, typical L/G ratios range from 1 to 3 liters of liquid per cubic meter of gas.
Ensure your pump sizing in Excel accounts for this total volume. ⚠️ Critical Checks for "Hot" Gas Scrubbers If your incoming gas is over 150∘C150 raised to the composed with power cap C ( 300∘F300 raised to the composed with power cap F
), you must build these safety checks into your Excel sheet:
Materials of Construction (MOC): Standard fiberglass (FRP) or plastics like PVC will melt. Your spreadsheet should flag temperatures and recommend High-Temperature FRP, Hastelloy, or a brick-lined quench section.
Make-up Water Rate: Account for massive water loss due to evaporation. Your Excel sheet must calculate: .
To help me tailor a specific set of formulas or a ready-to-copy tabular layout for your sheet, could you tell me: What is the inlet temperature of your hot gas? What specific pollutant are you trying to scrub (e.g., SO2cap S cap O sub 2 , HClcap H cap C l , or just fly ash/dust)? Do you prefer your calculations in SI units (Celsius, ) or Imperial units (Fahrenheit, CFMcap C cap F cap M )?
Wet Scrubber: Efficiency Сalculation, L/G Ratio, and Pressure Drop
Clients are sensitive to energy costs. The sheet must predict pressure drop across the packing.
Instead of manually typing packing factors, create a "Database" tab listing common packing types (e.g., 2" Pall Rings, 3" Saddles) and their associated Packing Factors ($F$), Surface Areas ($a$), and Void Fractions ($\epsilon$).
This is the critical design constraint.
$$ \Delta P = \fracu_t^2 \times L \times \rho_l1000 \times C_d \quad \text(Simplified units) $$
A more robust Excel formula using the Hesketh Equation: $$ \Delta P \approx \fracu_t^2 \rho_g A_t^0.1331270 \times \left( L/G \right) $$ (Note: Ensure consistent units: Pa or in. w.c.)