Chapter 9, Problem 9.75P

Interpretation Introduction

(a)

Interpretation:

The stream temperature of acetone is to be calculated when the relative saturation of acetone is $12.2\%$.

Concept introduction:

The stream temperature calculation is based on number of moles of acetone, relative saturation and total pressure at the inlet

Formula for calculation is given as

${\left(\mathrm{Re}lativeSaturation\right)}_{{}_{C_3{H}_{6}O}}=\left(\frac{y_i\times P_{C_3{H}_{6}O}}{p_{C_3{H}_{6}O}^{\ast }\left(T_f\right)}\right)$ ......... (1)

Here $y_i$ is the number of moles of $C_3{H}_{6}O$, $P_{C_3{H}_{6}O}$ is the total pressure of acetone entered,

$p_{C_3{H}_{6}O}^{\ast }\left(T_f\right)$ is the partial pressure for the acetone along with stream temperature

Mole fraction $\left(y_i\right)$ of any component is given by

$y_i=\frac{n_i}{\sum n_i}$ ......... (2)

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.

At (STP) condition volume is considered as $\text{22}{\text{.4 m}}^3$

Interpretation Introduction

(b)

Interpretation:

Composition of product formed before and after combustion and the temperature of exit stream is to be calculated.

Concept introduction:

Mole fraction $\left(y_i\right)$ of any component is given by

$y_i=\frac{n_i}{\sum n_i}$ ......... (2)

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.

Energy balance is used to calculate the temperature of exit stream is defined as the temperature attained by the product at the time of leaving the reactor.

$\Delta \text{H = }{n}_{C_3{H}_{6}O}\Delta {\hat{H}}_c^{\circ }+\sum _{out}n{\hat{H}}_i-\sum _{in}n{\hat{H}}_i$

$\Delta \text{H}$ is the change in enthalpy at ${25}^{\circ }C$

$\Delta {\hat{H}}_c^{\circ }$ is the heat of reaction

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

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

$\begin{array}{l}\sum _{out}n{\hat{H}}_i=n_{C{O}_2}{c}_{p_{C{O}_2}}\Delta T+n_{H_{2}O}{c}_p{}_{H_{2}O}\Delta T+n_{N_2}{c}_{P_{N_2}}\Delta T\\ \sum _{in}n{\hat{H}}_i=n_{C{O}_2}{c}_{p{C}_3{H}_{6}O}\Delta T+n_{O_2}{c}_p{}_{O_2}\Delta T+n_{N_2}{c}_{P_{N_2}}\Delta T\end{array}$

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

Interpretation Introduction

(c)

Interpretation:

The rate of heat transfer in $kW$ for the process before and after combustion is to be calculated. The process for switching of reactor is also to be suggested.

Concept introduction:

Amount of heat transferred in watt is calculated as

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

Based on average heat capacity and temperature.