Columna Absorción. Solución de Problema usando coeficientes de transferencia de masa:NH3+aire+agua

Session Overview

The session focuses on exercises related to the use of global and individual coefficients in a petrochemical plant scenario involving a column filled with ceramic saddles. Various parameters such as ammonia separation, gas mixture feeding, and transfer coefficients are discussed.

Plant Petrochemical Column Setup

• A petrochemical plant operates a column filled with ceramic saddles separating 95% of fed ammonia from a gas mixture of air-ammonia.

• The column functions isothermally at 20°C and isobarically at 800 mmHg pressure with a counter-current arrangement.

• Water-ammonia solution enters the column with specific concentrations, allowing for ideal system behavior described by given equations.

Coefficients and Transfer Rates

• Calculations involve average mass transfer coefficients for liquid film and global coefficients for gas phase.

• Questions posed include finding volumetric flow rate at the column inlet, velocity transfer ratios at different points, and individual volumetric coefficient for the gas film.

Diagram Construction and Parameters

• Constructing diagrams based on provided data regarding the plant's setup and operating conditions.

• Details about ammonia feed percentages, water-ammonia solution properties, and gas mixture flow rates are crucial for calculations.

Equilibrium Equations and Coefficients

• Further details on feeding gas mixtures, thermal conditions, equilibrium equations, average mass transfer coefficients in liquid phase are explored.

• Emphasis on calculating volumetric flow rates based on given concentrations at the column entry point.

Conclusion

New Section

In this section, the speaker discusses the process of finding L2b and emphasizes the importance of its placement in the calculation.

Finding L2b

• The speaker stresses that L2b needs to be at the top and explains the task of finding L1b L1 L2 volumetric.

• Describes how to obtain L2b using an expression involving total flow in moles and total density in moles, based on L2 being ls per 1 + x a2 May.

• Talks about homogenizing concentration units by transforming gas phase mole fraction to mole ratio, essential for further calculations.

New Section

This part delves into unit transformations for concentration and molecular weights to calculate liquid phase mole fraction.

Concentration Unit Transformation

• Explains transforming gas phase fraction to mole ratio using molecular weights of components A and B.

• Converts kilomoles of A to total solution moles ratio, leading to determining relationship moles for calculations.

• Derives equations for calculating ya2 from known values, crucial for subsequent graphical representation.

New Section

The discussion centers around graph plotting based on calculated values and further computations involving x1 and r de l L2.

Graph Plotting and Calculations

• Details obtaining key values like ya2 and xa2 necessary for plotting points on a graph.

• Continues with calculations involving ya1, emphasizing its significance in subsequent steps.

New Section

In this section, the instructor discusses graphing in the context of an absorption process, focusing on determining upper limits and constructing tables for further analysis.

Graphing in Absorption Process

• The upper limit for graphing is identified as 0.11.

• Construction of a table begins at 0.12 and progresses with incremental values.

• Students are instructed to plot the known point 0.529 and its corresponding coordinates.

• Emphasis is placed on accurately positioning points on the graph for precise readings.

• Ensuring a well-structured grid layout aids in clear interpretation during analysis.

New Section

This segment delves into calculating values crucial for further analysis, including liquid flow rates and concentrations at interfaces.

Calculations for Analysis

• Calculation of liquid flow rate (L1) yields 1.161 kmol/hour.

• Subsequent calculations involve determining L2B by dividing LS by (1 + 1/11), resulting in 7.76.

• Transitioning to concentration calculations, R2 is computed as 54.9962 cubic meters of L2 per hour.

• Conversion to liters simplifies the volume calculation to 21.23 L2 per hour.

• Moving forward, interface concentrations are explored through flux calculations using specific coefficients.

New Section

This part focuses on deriving interface concentrations based on flux calculations and coefficient considerations.

Interface Concentrations Computation

• Interface concentrations are determined utilizing flux values, specifically Flux 2.

• The calculation involves coefficients related to phase liquid molar relationships.

• Coefficients are expressed in terms of mol ratios per unit area per time gradient (kmol/hour/m^2).

• Detailed steps include substituting known values into equations for accurate interface concentration determination.

• Understanding individual coefficients' significance enhances comprehension of interface concentration dynamics.

Despejando Ecuaciones y Calculando Coeficientes

In this section, the speaker discusses solving equations and calculating coefficients in a chemical engineering context.

Despejando Ecuaciones

• The speaker instructs to clear the equation given at the beginning of the class, resulting in a value of 0.0015.

• They mention completing the calculation for Y2i testado and preparing to calculate Y2i.

Calculando Coeficientes

• The equation for Ya* is derived as 824 times Xa1.

• The process of finding interfaces is discussed, with an example calculation leading to a value of 0.077.

Relación de Velocidades de Transferencia y Coeficiente Global

This part focuses on discussing transfer velocities and global coefficients in chemical engineering applications.

Velocidades de Transferencia

• Explanation on finding the ratio between transfer velocities at the base and top of a column.

• Calculation method for flux at different points within the system using known values like average mass transfer coefficient.

Coeficiente Global en Fase Líquida

• Detailed steps to determine the relationship between Na1 and Na2, indicating higher transfer rates at one location compared to another.

• Further discussion on flux ratios highlighting significant differences in transfer rates between locations.

Cálculo del Coeficiente Global para el Domo

Exploring how to calculate global coefficients specifically for a dome structure in liquid phase scenarios.

Determinación del Coeficiente Global

• Instructions are provided on calculating a global coefficient (Kl2) for the dome structure focusing on liquid-phase parameters.

New Section

In this section, the discussion revolves around converting concentrations from kilograms per cubic meter to moles and calculating specific values based on known data.

Conversion of Concentrations and Calculations

• : Multiplying the concentration by a factor to convert it from kilograms per cubic meter to moles.

• : Utilizing known values like 54.9962 to calculate specific concentrations by multiplying with appropriate factors.

• : Determining which variables are of interest in the equilibrium equation and focusing on converting concentrations accordingly.

• : Working with different interfaces and known values to derive specific concentration values for further calculations.

Despejando Coeficientes y Calculando Densidades

In this section, the speaker discusses calculating flux and coefficients in a chemical engineering context.

Calculating Flux 1

• The process of calculating flux 1 involves multiplying the volumetric flux by the interfacial area.

• The calculation includes multiplying by the average mass transfer coefficient and the area.

• Factors such as average mass transfer coefficient values are considered in these calculations.

Understanding Pressure Gradients

• Pressure gradients are crucial in determining partial pressures, impacting calculations involving atmospheric units.

• Units like atmospheres play a role in canceling out during calculations based on Dalton's law.

Calculating Coefficients for Gas Phase

This part focuses on deriving coefficients for gas phases through detailed calculations and considerations.

Deriving Coefficient Kc A1

• The process involves identifying individual coefficients and considering gas phase properties.

• Calculation steps include determining gas density and utilizing known values to find coefficient values accurately.

Determining Density Values

• Calculations involve finding molar densities based on given data and established formulas.

• Further computations lead to obtaining molar densities at interfaces, essential for subsequent calculations.

Utilizing Equilibrium Equations

• Equilibrium equations guide the derivation of key parameters necessary for accurate coefficient determination.

Despejando Coeficientes Volumétricos en Ingeniería Química

In this section, the speaker discusses the process of solving for volumetric coefficients in chemical engineering calculations.

Despeje de Xa1

• The value of Xa1 needs to be determined.

• Calculations are performed to find Xa1, considering various values and equations.

Cálculo de Coeficiente Individual Volumétrico

• Density calculations are carried out for kilomoles of A over total kilomoles.

• The individual volumetric coefficient is solved for gas phase density with appropriate units conversion.

Determining Individual Volumetric Coefficients

This part focuses on calculating individual volumetric coefficients in chemical engineering applications.

Cálculo para Kca2

• The process is repeated for Kca2, emphasizing precision and attention to detail.

• Conversion from non-volumetric flux to volumetric flux is explained and applied in calculations.

Determinación de C2g y C2ig

• Steps are outlined for determining C2g and C2ig by multiplying gradients with respective densities.

• Consideration of gas density variations at different stages of a process is discussed.

Finalizing Volumetric Coefficients Calculation

Concluding the calculation process for individual volumetric coefficients in chemical engineering scenarios.

Sustitución y Resultados Finales

• Specific conditions are considered for final density calculations, ensuring accuracy in results.