Scrubber Design Calculation Excel Hot

Scrubber Design Calculation: A Step-by-Step Guide

A scrubber is a crucial piece of equipment in various industrial processes, used to remove pollutants and contaminants from gas streams. Designing a scrubber requires careful consideration of several factors, including gas flow rate, pollutant concentration, and scrubbing liquid properties. In this story, we'll walk through a step-by-step guide on how to perform scrubber design calculations using Excel.

The Problem

A chemical plant is looking to install a scrubber to remove sulfur dioxide (SO2) from its flue gas stream. The plant's engineers need to design a scrubber that can handle a gas flow rate of 10,000 Nm³/h, with an SO2 concentration of 500 ppm. The scrubbing liquid will be a solution of sodium hydroxide (NaOH).

Step 1: Define the Design Parameters

| Parameter | Value | Unit | | --- | --- | --- | | Gas flow rate (Q) | 10,000 | Nm³/h | | SO2 concentration (C) | 500 | ppm | | Scrubbing liquid | NaOH solution | - | | Temperature (T) | 25 | °C | | Pressure (P) | 1 | atm |

Step 2: Calculate the Molar Flow Rate of SO2

To calculate the molar flow rate of SO2, we need to convert the volumetric flow rate from Nm³/h to mol/h.

$$ \textMolar flow rate of SO2 = Q \times C \times \frac110^6 \times \fracPR \times T $$

where R is the gas constant (8.314 J/mol·K).

Assuming ideal gas behavior, we can simplify the calculation:

$$ \textMolar flow rate of SO2 = 10,000 \times 500 \times \frac110^6 \times \frac122.4 = 223.2 , \textmol/h $$

Step 3: Determine the Scrubber Type and Size

Based on the molar flow rate of SO2, we can select a suitable scrubber type and size. For this example, let's assume a packed tower scrubber with a packed height of 5 meters.

Step 4: Calculate the Liquid Flow Rate

The liquid flow rate (L) can be calculated using the following equation:

$$ L = \frac\textMolar flow rate of SO2 \times \textStoichiometric ratio\textMolecular weight of NaOH \times \textDensity of NaOH solution $$

Assuming a stoichiometric ratio of 1.5 and a NaOH solution density of 1,000 kg/m³:

$$ L = \frac223.2 \times 1.540 \times 1000 = 8.37 , \textm³/h $$

Step 5: Calculate the Scrubber Diameter

The scrubber diameter (D) can be calculated using the following equation:

$$ D = \sqrt\frac4 \times Q\pi \times v $$

where v is the superficial gas velocity ( typically 1-3 m/s).

Assuming a superficial gas velocity of 2 m/s:

$$ D = \sqrt\frac4 \times 10,0003600 \times \pi \times 2 = 1.33 , \textm $$

Excel Calculation

We can now create an Excel spreadsheet to perform these calculations.

| Parameter | Value | Formula | | --- | --- | --- | | Gas flow rate (Q) | 10,000 | - | | SO2 concentration (C) | 500 | - | | Molar flow rate of SO2 | 223.2 | =Q*C/10^6*1/22.4 | | Liquid flow rate (L) | 8.37 | =223.2*1.5/40/1000 | | Scrubber diameter (D) | 1.33 | =SQRT(4*10000/3600/PI()/2) |

By following these steps and using Excel to perform the calculations, we can quickly and accurately design a scrubber system that meets the plant's requirements.

Conclusion

In this story, we walked through a step-by-step guide on how to perform scrubber design calculations using Excel. By defining the design parameters, calculating the molar flow rate of SO2, determining the scrubber type and size, calculating the liquid flow rate, and calculating the scrubber diameter, we can design a scrubber system that effectively removes pollutants from gas streams.

Designing a wet scrubber for hot gas streams—such as flue gas from industrial combustion—requires balancing mass transfer with significant thermal changes. The following guide outlines the core design calculations, specifically tailored for an Excel-based implementation, focusing on the unique challenges of "hot" inlet gases. Core Scrubber Design Process

The design of a scrubber for hot gases is an iterative process that begins with understanding the physical properties of the gas at its saturated state. 1. Calculate Adiabatic Saturation Temperature ( Tsatcap T sub s a t end-sub

When a hot gas enters a wet scrubber, it is cooled by the evaporation of the scrubbing liquid. For engineering purposes, the gas is assumed to reach its adiabatic saturation temperature. In Excel, you can solve for Tsatcap T sub s a t end-sub using the following energy balance:

s(Tin−Tsat)=λ(Hsat−Hin)s open paren cap T sub i n end-sub minus cap T sub s a t end-sub close paren equals lambda open paren cap H sub s a t end-sub minus cap H sub i n end-sub close paren : Humid heat of the gas. Tincap T sub i n end-sub : Inlet gas temperature. : Latent heat of vaporization at Tsatcap T sub s a t end-sub

: Initial and saturation humidity ratios (lb water/lb dry gas). Excel Tip: Use the Excel Solver Add-in to find the Tsatcap T sub s a t end-sub that balances this equation, as Hsatcap H sub s a t end-sub are both temperature-dependent. 2. Determine Saturated Gas Flow Rate ( Qsatcap Q sub s a t end-sub

Hot gases occupy a larger volume than cooled gases. Once you have Tsatcap T sub s a t end-sub

, you must calculate the volumetric flow rate of the gas at this lower temperature to size the vessel correctly:

Qsat=Qin⋅TsatTin⋅PinPsat+Volume of Added Water Vaporcap Q sub s a t end-sub equals cap Q sub i n end-sub center dot the fraction with numerator cap T sub s a t end-sub and denominator cap T sub i n end-sub end-fraction center dot the fraction with numerator cap P sub i n end-sub and denominator cap P sub s a t end-sub end-fraction plus Volume of Added Water Vapor

Calculations must be performed on a dry gas basis to account for the additional water vapor added during cooling. 3. Sizing the Tower Diameter Individual Design of 2 Scrubbers - UKDiss.com

* 2.2.2.3 Calculation of % flooding. From Figure 1, K4 at flooding = 8. % flooding: 100*K4K4 flooding0.5=100*380.5=61.24% * 2.2.2. UKDiss.com

Venturi Scrubber Design Calculations | PDF | Gases | Liquids - Scribd

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) scrubber design calculation excel hot

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

The design of a wet scrubber—whether for particulate removal or gas absorption—requires a systematic calculation process to determine critical dimensions and operational parameters. Utilizing a structured Excel spreadsheet

allows engineers to quickly iterate through design variables like gas flow rates, temperature, and pressure drops to find an optimal configuration. 1. Define Design Inputs and Gas Conditions

The first step is establishing the "source" data. In an Excel sheet, these are typically grouped in a dedicated "Inputs" tab. Gas Stream Properties : Include the inlet volumetric flow rate (e.g., in ), inlet temperature, and pressure. Saturation Calculations

: For hot gases, the scrubber will saturate the stream. You must calculate the saturated gas flow rate cap Q sub s a t end-sub ) and temperature ( cap T sub s a t end-sub

) using a psychrometric chart or humidity ratios. The scrubber is sized based on this saturated outlet volume, not the hot inlet volume. Target Efficiency : Define the required collection efficiency (e.g., for particulates) based on regulatory standards. 2. Determine Column Diameter The column diameter ( ) is primarily a function of the gas velocity required to avoid flooding while maintaining contact time. Calculation

: Divide the saturated volumetric flow rate by the allowable shell velocity (typically around for spray towers). Cross-Sectional Area ( cap A sub s

cap A sub s equals the fraction with numerator cap Q sub s a t end-sub and denominator v end-fraction Diameter (

cap D equals the square root of the fraction with numerator 4 cross cap A sub s and denominator pi end-fraction end-root Hydraulic Check : For packed towers, the Excel sheet should check the % Flooding (typically designed for

) using correlations like Norton’s to ensure the gas can move through the packing without pushing the liquid back up. 3. Calculate Tower Height and Packing

The height ensures sufficient contact time between the gas and the scrubbing liquid. Wet scrubber design calculation xls

For designing and calculating wet scrubbers in Excel, there are several specialized templates and resources available that cover hydraulic design, mass transfer, and cost estimation. Excel Calculation Templates Spray Tower Scrubber Rating: Meloni Marco

offers a downloadable spreadsheet for preliminary single-stage spray tower calculations, including removal efficiency and pressure losses.

EPA Scrubber Cost & Design: The U.S. EPA provides comprehensive workbooks like the Wet & Dry FGD Data Inputs

and cost calculation spreadsheets for packed bed and flue gas desulfurization (FGD) systems.

Packed Bed Design: Engineering forums like Cheresources host community-shared files such as scrubber_design.xls and Packed bed+ hetp.xls for tower sizing. Wet Scrubber Design Excel Sheet | PDF - Scribd

The first step is to establish the properties of the incoming hot gas. Because the gas is "hot," you must account for its actual volume at operating temperature rather than standard conditions. Gas Flow Rate ( Vincap V sub i n end-sub ): Define in ACFM (Actual Cubic Feet per Minute) or Inlet Temperature ( Tincap T sub i n end-sub ): Note the temperature (e.g., 400∘F400 raised to the composed with power cap F 590∘C590 raised to the composed with power cap C Scrubber Design Calculation: A Step-by-Step Guide A scrubber

Contaminant Data: Identify the molecular weight and concentration (ppm or ) of the component to be removed (e.g., HCl, H2Scap H sub 2 cap S Gas Properties: Calculate gas density ( ρgrho sub g

) at inlet temperature and pressure using the Ideal Gas Law. 2. Perform Humidification and Saturation Calculations

Hot gases will evaporate the scrubbing liquid until they reach the adiabatic saturation temperature ( Tsatcap T sub s a t end-sub

). The scrubber must be sized for the saturated gas volume, not the inlet volume. Determine Saturation Temperature ( Tsatcap T sub s a t end-sub

): Use a psychrometric chart or humidity balance to find the temperature at which the gas becomes saturated with moisture. Calculate Saturated Gas Flow ( Qsatcap Q sub s a t end-sub ):

Qsat=Qin×Volume Correction Factorcap Q sub s a t end-sub equals cap Q sub i n end-sub cross Volume Correction Factor For example, a gas at 450∘F450 raised to the composed with power cap F might have a correction factor of 3. Determine Column Diameter

The tower diameter is typically calculated to avoid "flooding," where upward gas velocity prevents downward liquid flow.

Select Packing Material: Choose a packing type (e.g., Intalox Saddles, Rosette) and its specific Packing Factor ( Fpcap F sub p ).

Calculate Flooding Velocity: Use the Generalized Pressure Drop Correlation (GPDC). Aim for an operating velocity between of the flooding velocity. Find Cross-Sectional Area ( Ascap A sub s ):

As=Qsatvgascap A sub s equals the fraction with numerator cap Q sub s a t end-sub and denominator v sub g a s end-sub end-fraction vgasv sub g a s end-sub is the selected design gas velocity (e.g., Final Diameter ( ):

D=4×Asπcap D equals the square root of the fraction with numerator 4 cross cap A sub s and denominator pi end-fraction end-root 4. Determine Packing Height

The required height depends on the mass transfer efficiency needed to meet outlet concentration targets.

HCL Packed Column Scrubber Design | PDF | Mole (Unit) - Scribd

This goes far beyond a simple pressure drop sheet. It is structured as a multi-module thermodynamic & hydraulic design tool.

Building the Ultimate "Scrubber Design Excel Hot" Template

You can download generic calculators, but here is how to build the professional-grade version that stands out.

Step 5: Collection Efficiency (Calvert Cut-Power Model)

The Excel sheet should calculate the "Cut Diameter" ($d_pc$)—the particle size collected with 50% efficiency.

$$ d_pc = \sqrt\frac9 \mu_g D_du_t \rho_p C_c \times \left( \frac1K \right) $$

Where:

$\mu_g$ = Gas viscosity
$D_d$ = Droplet diameter (estimated via Nukiyama-Tanasawa equation)
$K$ = Constant based on geometry (~0.5)

Overall Penetration ($Pt$): $$ Pt = \exp \left( - \left( \fracd_pd_pc \right)^B \right) $$ Efficiency $\eta = 1 - Pt$.

5.0 Spreadsheet Architecture

The Excel file should be organized into the following tabs:

Tab 3: Outputs & Sizing

Mechanical Dimensions: Throat length, convergence angle (25°–30°), divergence angle (5°–7°).
Nozzle Selection: Required spray pressure and nozzle orifice size based on $Q_L$.

Conclusion: The "Hot" Download You Need

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:

☑ Iterative solver for outlet temperature (Goal Seek or circular reference).
☑ Psychrometric functions for humidity and latent heat.
☑ Velocity check at both inlet AND outlet temperature.
☑ Droplet evaporation model.
☑ Alerts for high sump temperature (>160°F).

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.

This write-up covers the thermodynamic principles, the step-by-step calculation logic required for the Excel model, and the critical design parameters. Building the Ultimate "Scrubber Design Excel Hot" Template

Mastering Scrubber Design: A Guide to Calculation Spreadsheets

Tab 3: Mechanical Sizing

Vessel diameter based on Souders-Brown equation (using gas density at average temperature).
Height based on Number of Transfer Units (NTU) for mass transfer.
Critical: Check for flooding velocity using the corrected hot gas density.