Chapter 9, Problem 9.35P

Interpretation Introduction

(a)

Interpretation:

The rate at which the two feed streams enter the reactor are to be calculated.

Concept introduction:

A flowchart is the complete representation of a process through boxes or other shapes which represents process units and arrows that represents the input and output of the process. The flowchart must be fully labelled to infer important data about the process involved.

In a system, a conserved quantity (total mass, mass of a particular species, energy or momentum) is balanced and can be written as:

$input+generation-output-consumpumtion=accumulation$

Here, ‘ input’ is the stream which enters the system. ‘ generation’ is the term used for the quantity that is produced within the system. ‘ output’ is the stream which leaves the system. ‘ consumption’ is the term used for the quantity that is consumed within the system. ‘ accumulation’ is used for the quantity which is builds up within the system.

All the equations which are formed are then solved simultaneously to calculate the values of the unknown variables.

Interpretation Introduction

(b)

Interpretation:

The composition and molar flowrate of product stream C are to be calculated.

Concept introduction:

In a system, a conserved quantity (total mass, mass of a particular species, energy or momentum) is balanced and can be written as:

$input+generation-output-consumpumtion=accumulation$

Here, ‘ input’ is the stream which enters the system. ‘ generation’ is the term used for the quantity that is produced within the system. ‘ output’ is the stream which leaves the system. ‘ consumption’ is the term used for the quantity that is consumed within the system. ‘ accumulation’ is used for the quantity which is builds up within the system.

All the equations which are formed are then solved simultaneously to calculate the values of the unknown variables.

The formula to calculate the mole fraction $\left(y_i\right)$ of species $i$ is:

$y_i=\frac{{\dot{n}}_i}{{\dot{n}}_T}$ ......(7)

Here, ${\dot{n}}_i$ is the molar flowrate of the species $i$ in the mixture and ${\dot{n}}_T$ is the total molar flowrate of the mixture.

Interpretation Introduction

(c)

Interpretation:

The energy balance equation around the reactor is to be written. Also, the rate at which ethyl chloride is recycled is to be determined.

Concept introduction:

The equation for energy balance is:

$\Delta \dot{H}+\Delta {\dot{E}}_{\text{k}}+\Delta {\dot{E}}_{\text{p}}=\dot{Q}-{\dot{W}}_{\text{s}}$ ......(8)

Here, $\Delta \dot{H}$ is the rate of change in the enthalpy of the system, $\Delta {\dot{E}}_{\text{k}}$ is the rate of kinetic energy change of the system, $\Delta {\dot{E}}_{\text{p}}$ is the rate of potential energy change of the system, $\dot{Q}$ is the net rate at which energy is transferred to a system and ${\dot{W}}_{\text{s}}$ is the rate at which energy is transferred as shaft work.

Specific heat capacity $\left(C_p\right)$ of a substance is the amount of heat needed for a unit mass of substance to raise its temperature by $1^{\circ }\text{C}$. It is temperature dependent and varies with temperature of the substance.

Specific enthalpy $\left(\hat{H}\right)$ of any substance at temperature $T^{\circ }\text{C}$ is given by:

$\hat{H}={\int }_{T_{ref}}^T{C}_{p}dT$ ......(9)

Here, $T_{ref}$ is the reference temperature taken for the calculations.

Heat of formation is the change in enthalpy associated with the formation of the compound at the reference temperature and pressure.

Interpretation Introduction

(d)

Interpretation:

The assumptions made during the analysis of the process are to be listed.