Chapter 9, Problem 9.24P

Interpretation Introduction

(a)

Interpretation:

The cooling requirement of the reactor in $\text{kJ/mol feed}$ is 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.

The formula for the fractional conversion $\left(f\right)$ is:

$f=\frac{\text{moles reacted}}{\text{moles fed}}$

…… (1)

The equation for energy balance is:

$\Delta H+\Delta E_{\text{k}}+\Delta E_{\text{p}}=Q-W_{\text{s}}$

…… (2)

Here, $\Delta H$ is the change in the enthalpy of the system, $\Delta E_{\text{k}}$ is the kinetic energy change of the system, $\Delta E_{\text{p}}$ is the potential energy change of the system, $Q$ is the net energy which is transferred to a system and $W_{\text{s}}$ is the word done by the shaft.

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:

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

…… (3)

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

Interpretation Introduction

(b)

Interpretation:

The reason for the reactor to yield low conversion of ethylene is to be stated. Also, the steps to be followed for the reactor to be commercially implemented for this process is to be explained.