Chapter 9, Problem 9.26P

Interpretation Introduction

(a)

Interpretation:

The volumetric flow rate in ${\text{ft}}^{\text{3}}\text{/hr}$ needs to be calculated for feed stream and product gases.

Concept introduction:

Volumetric flow rate is calculated using volume calculated by ideal gas law and scale factor which is defined as the ratio of number of moles of actual fed to the number of moles taken as basis

$\%\text{Excess}\text{air}=\left(\frac{{\left(n_{\text{air}}\right)}_{\text{feed}}\text{-}{\left(n_{\text{air}}\right)}_{\text{theoritical}}}{{\left(n_{\text{air}}\right)}_{\text{theoritical}}}\right)$

Percent excess air is the ratio of difference between the number of moles of air feed and moles of air theoretically required to number of moles theoretically required.

Interpretation Introduction

(b)

Interpretation:

Rate of heat transfer from the reactor in $\text{Btu/hr}$ and flow rate of cooling water is to be calculated.

Concept introduction:

The amount of heat transferred is calculated by:

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

Where,

$\sum _{out}n{\hat{H}}_i$ 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.

Energy Transfer for cooling is calculated as follows:

$Q\text{}=\Delta H=m_w{\underset{T_2}{\overset{T_1}{\int }}\left(c_p\right)}_{H_{2}O}dT$

Here,

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

$c_p$ is the heat capacity of water in $\frac{\text{Btu}}{{\text{lb}}_{\text{m}}{\text{.}}^{\text{o}}\text{F}}$

$m_w$ be the flow rate of cooling water

Interpretation Introduction

(c)

Interpretation:

State the causes of problem if the flow rate of coolant is increased and the product gases temperature cannot attain the given temperature value.

Concept introduction:

Energy Transfer for cooling is calculated as follows:

$Q\text{}=\Delta H=m_w{\underset{T_2}{\overset{T_1}{\int }}\left(c_p\right)}_{H_{2}O}dT$

Here,

$Q\text{}=$ Amount of heat transfer in $\text{Btu}$.

$c_p$ is the heat capacity of water in $\frac{\text{Btu}}{{\text{lb}}_{\text{m}}{\text{.}}^{\text{o}}\text{F}}$.

$m_w$ be the flow rate of cooling water.