Chapter 4, Problem 4.55P

(a)

Interpretation Introduction

Interpretation:

Calculate the standard heat of combustion in $\frac{\text{kJ}}{\text{mol}}$ of a fuel at ${\text{25}}^{\text{o}}\text{C}$ consists $\text{85\%}$ in mol methane, 10 mol% ethane and $\text{5\%}$ oxygen. If water in gas is one of the products after reaction.

Concept Introduction:

The standard heat of combustion can be calculated as:

  $\Delta H^{\circ }{}_f=\Delta H^{\circ }{}_P-\Delta H^{\circ }{}_R$........(1)

(b)

Interpretation Introduction

Interpretation:

The fuel is supplied to a furnace with $\text{50\%}$ excess air both entering at ${\text{25}}^{\text{o}}\text{C}$ and product leaves at ${600}^{\text{o}}\text{C}$ . If combustion is complete and no side reaction occur, how much heat $\frac{\text{kJ}}{\text{mol}}$ is transferred to furnace.

Concept Introduction:

The heat of reaction to temperature of product can be calculated as:

  $\Delta H^{\circ }=\Delta H^{\circ }{}_0+R{\displaystyle \underset{T_0}{\overset{T}{\int }}\frac{\Delta C^{\circ }{}_P}{R}dT}$........(1)

Where $\Delta H^{\circ }$ is heat of reaction at any temperature $T$, $\Delta H^{\circ }{}_0$ is heat of reaction at standard temperature $T_0$ and

  ${\displaystyle \underset{T_0}{\overset{T}{\int }}\frac{\Delta C^{\circ }{}_P}{R}dT}=(\Delta A)T_0(\tau -1)+\frac{\Delta B}{2}{T}_0{}^2({\tau }^2-1)+\frac{\Delta C}{3}{T}_0{}^3({\tau }^3-1)+\frac{\Delta D}{T_0}(\frac{\tau -1}{\tau })$.....(2)

Where $\tau =\frac{T}{T_0}$