Chapter 9, Problem 9.34P

Interpretation Introduction

(a)

Interpretation:

The flowchart of the process needs to be prepared, considering absorption and distillation as a single unit.

Concept introduction:

Flow chart is diagrammatic representation of the reaction taking place in the reactor.

The calculation of flowchart is based on the relation

$\text{Input}\text{-}\text{Output}\text{=}\text{Accumulation}$

It helps to determine the amount of product formed with respect to the amount of reactant fed to the reactor.

Interpretation Introduction

(b)

Interpretation:

The operating temperature of methanol vaporizer needs to be determined.

Concept introduction

Raoult’s law: This law implies that a given temperature the value of vapor pressure is equal to the product of mole fraction of components and total pressure.

The relationship is gives as

$y_m\times P=P_m\times \left(T_m\right)$

Here,

$y_m$ is the number of moles of components

$P$ is the total pressure of components

$P_m$ is the vapor pressure with respect to the temperature ${\left(T_m\right)}^{\circ }C$

Antoine equation used to determine the temperature using partial pressure in $\text{mm}\text{Hg}$

${\log }_{10}\left(P\right)=A-\frac{B}{C+T}$

$P$ is the vapor pressure in $mmHg$

$T$ is the temperature in ${}^{\circ }\text{C}$

A, B and C are the constants with respect to components and temperature

If the vapor pressure in $\text{mm}\text{Hg}$ the calculation of temperature by using relation

$T=\frac{B}{A-{\log }_{10}\left(P\right)}-C$

This relationship correlates the temperature with vapor pressure.

Interpretation Introduction

(c)

Interpretation:

The feed rate of stream in $Kg/hr$ and product gas composition along with molal flow rate needs to be determined.

Concept introduction:

Mole fraction $\left(y_i\right)$ of any components given by:

$y_i=\frac{n_i}{\sum n_i}$

Here, $n_i$ is the moles of component $i$ and $\sum n_i$ is the total moles of all the components present in the mixture.

The below equation used to calculate the amount of heat transfer

$\Delta H=\Delta {\hat{H}}_f^{\circ }+\underset{T_2}{\overset{T_1}{\int }}\left(c_p\right)dT$

$Q\text{}=$ Amount of heat transfer

$c_p$ is the heat capacity of components

Interpretation Introduction

(d)

Interpretation:

The steam rate generation in $\text{kg/hr}$ for waste heat boiler needs to be determined.

Concept introduction:

Relation gives the amount of heat generation:

$Q\text{}=\sum _{out}n{\hat{H}}_i-\sum _{in}n{\hat{H}}_i$

Here,

$\sum _{out}n{\hat{H}}_i$ is the heat of formation of product.

$\sum _{in}n{\hat{H}}_i$ is the heat of formation of reactant.

Enthalpy of reactant and product depends upon the specific heat and the temperature difference.

Interpretation Introduction

(e)

Interpretation:

The impact of steam on outlet temperature needs to be explained.

Concept introduction:

The amount of heat transfer

$\Delta H=\Delta {\hat{H}}_f^{\circ }+\underset{T_2}{\overset{T_1}{\int }}\left(c_p\right)dT$

$Q\text{}=$ Amount of heat transfer

$c_p$ is the heat capacity of components

The concept is based on heat exchangers.