Scrubber Design Calculation Excel Hot _hot_ -

Designing a scrubber—specifically for hot gas streams—requires accounting for gas cooling (humidification) before sizing the physical vessel. Most Excel-based guides follow a specific sequence to determine the required tower diameter and height based on mass transfer or particulate removal needs. 1. Pre-Design Step: Humidification (Hot Gas Adjustment)

Before sizing the tower, you must calculate the saturated gas flow rate. Hot inlet gas will evaporate scrubbing liquid, increasing the gas volume and cooling it to its adiabatic saturation temperature.

Identify Inlet Conditions: Inlet gas temperature, pressure, and moisture content (lb water/lb dry gas).

Calculate Saturation: Use psychrometric data to find the saturation temperature and the resulting Saturated Gas Flow Rate (ACFM). This saturated volume is the basis for all subsequent diameter calculations. 2. Sizing the Scrubber Diameter

The diameter is typically limited by gas velocity to prevent "flooding" or excessive pressure drop.

Set Design Velocity: For common spray towers, a typical velocity is approximately Calculate Area ( ): Calculate Diameter ( ):

Check Flooding (Packed Towers): If using packing, aim for a "flooding" percentage between . If it exceeds this, increase the diameter. 3. Calculating Scrubber Height

Height depends on the required efficiency for gas absorption (mass transfer) or particulate removal.

Height of a Transfer Unit (HTU): A measure of the mass transfer efficiency of the packing material or spray.

Number of Transfer Units (NTU): Based on the log-mean concentration difference between the inlet and outlet pollutants. Total Height ( ): Safety Factor: For standard designs, adding a

design safety factor to the calculated height is common practice. 4. Pressure Drop and Power

Total system pressure drop dictates the fan size needed to pull or push gas through the scrubber. Calculate ΔPcap delta cap P scrubber design calculation excel hot

: Use correlations (like the Hesketh Equation for Venturis) to find the pressure drop based on liquid-to-gas ( ) ratios and gas velocity.

Fan Power: Calculate the required blower capacity based on the total pressure drop and the polluted air flow rate. Recommended Excel Resources

You can find pre-built templates and detailed manuals at these authoritative sites: Scrubber Design and Calculation Report | PDF - Scribd

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

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

3. Pressure Drop Calculation Suite (High Temp Correction)

Pressure drop is critical for fan sizing and operating cost. This module includes:

  • Gas density correction for high temperature (ρ = ρ_std * (273 / (T_in + 273)) ).
  • Venturi scrubber pressure drop (Calvert or Johnstone): [ \Delta P = K \cdot v_t^2 \cdot (L/G)^0.5 ] where K is user-calibrated constant.
  • Packed bed pressure drop (Ergun equation modified for two-phase flow).
  • Nozzle pressure drop for spray systems (based on nozzle type and flow rate).

Live flag: “ΔP > 15 kPa? → Check fan power limit” Gas density correction for high temperature (ρ =

Excel Implementation Notes

  • Use named ranges for all inputs (e.g., GasFlow, TempIn, L_G_ratio).
  • Apply data validation to prevent non-physical entries (e.g., T_out > T_in).
  • VBA macros recommended for iterative loops (adiabatic saturation, efficiency solver).
  • Protect cells containing formulas to prevent user corruption, but leave input cells unlocked.
  • Use conditional formatting to highlight warnings (red background) and optimal ranges (green).

If you want, I can also provide the Excel formulas (e.g., for adiabatic saturation, pressure drop, or d50) so you can implement them directly into cells. Just let me know which module you'd like to start with.

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

3.0 Theoretical Basis

1.0 Executive Summary

This document outlines the methodology for designing a Venturi Scrubber system intended for hot gas cleaning. The design focuses on removing particulate matter (PM) from high-temperature flue gases using a liquid spray. The accompanying Excel calculation tool utilizes iterative algorithms to determine the throat dimensions, pressure drop, liquid-to-gas ratio (L/G), and overall collection efficiency.

Module 1: Adiabatic Saturation Temperature (T_wb)

For a hot gas stream entering a well-insulated scrubber (adiabatic), the gas will cool to the adiabatic saturation temperature (wet-bulb temperature), assuming sufficient liquid flow and residence time. venturi scrubber sizing spreadsheet

The Heat Balance Equation (Imperial Units):

Q_sensible = Q_latent

M_gas * Cp_gas * (T_in - T_out) = M_evap * h_fg

Where:

  • M_evap = Water evaporated (lb/hr)
  • h_fg = Latent heat of vaporization (~970 BTU/lb)

Excel Challenge: T_out is not known because the humidity ratio changes. You must use Goal Seek or iterative circular logic.

  • Cell A: Guess T_out.
  • Cell B: Calculate saturation vapor pressure at T_out (Use Antoine Equation or lookup table).
  • Cell C: Calculate humidity ratio change.
  • Cell D: Calculate heat balance error.
  • Iterate until error < 0.1 BTU/hr.

Step 3: Liquid-to-Gas Ratio (L/G) Optimization

For hot gases, L/G ratios of 1.0 to 2.5 L/m³ are typical. Create a sensitivity table in Excel (Data > What-If Analysis > Data Table) showing:

  • L/G vs. ΔP vs. T_out_gas.
  • You will see that increasing water flow initially cools but eventually wastes pumping power.

1. Energy Balance (Adiabatic Cooling)

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.

  • Excel Implementation: Use Solver or Goal Seek to find T_out where the energy out balances the evaporation cooling.

Conclusion

The search for "scrubber design calculation excel hot" is not about finding any spreadsheet—it is about finding the right thermodynamic engine. A standard isothermal calculator will overestimate efficiency and underestimate vessel size by a factor of 2 or more.

By building or purchasing an Excel tool that solves the adiabatic energy balance, corrects gas viscosity for temperature, and uses saturated gas volume for velocity calculations, you move from guessing to engineering.

Next Step: [Download the Pro-Tier "Hot Gas Venturi Scrubber Calculator" Excel Template (VBA Enabled)] – Includes psychrometric loop, material selector, and 3D output chart.

Author Bio: The author is a process engineer with 15 years of experience in cement kiln and incinerator scrubber retrofits.

Keywords: scrubber design calculation excel hot, venturi scrubber sizing spreadsheet, high temperature gas cleaning, adiabatic saturation Excel tool, packed bed scrubber thermal design.

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