Hi$,$

$$Please could you answer parts d$,$e and f of the below question and explain and expand all working so that it is clearly visable in step by step format and the steps explained where necessary for further clarification.

Thankyou in advance for your help.

A fuel gas consists of $75\%$ butane $(C_4{H}_{10}),10\%$ propane $(C_3{H}_8)$ and $15\%$

butene $(C_4{H}_8)$ by volume.

It is to be fed to the combustion chamber in $10\%$ excess air at $25C,$ where

it is completely burnt to carbon dioxide and water. The flue gases

produced are to be used to generate $5$ bar steam from water at $90C.$

With the aid of the data at the end of the question, steam tables and the

enthalpy table given in the Appendix of lesson HTC $-4-2$ :

$($a$)$ Write balanced equations for the combustion of each component of the

fuel gas.

$($b$)$ Explain the need for excess air.

$($c$)$ Determine the actual fuel:air ratio

$($i$)$ by volume $($ii$)$ by mass.

$($d$)$ Calculate:

$($i$)$ the net calorific value $(CV)$ per $m^3$ of the

fuel$/$air mix at $25C($ii$)$ the net calorific

value $($CV$)$ per kmol of the fuel$/$air mix at

$25C.$

$($e$)$ Determine the composition of the flue gases by volume $($assuming the

inlet air is dry$)$:

$($i$)$ on a wet basis

$($ii$)$ on a dry basis.

$($f$)$ Determine the 'furnace efficiency' if the flue gases leave the boiler

at $300C.$

$($g$)$ Give two advantages of preheating the water in this way and one

disadvantage.

$($h$)$ Give two reasons why the presence of any sulphur in the fuel mix

would be undesirable.

Data:

Net calorific value $(MJ{m}^{-3})$ at $25C$ of:

Butane $(C_4{H}_{10})=111\mathrm{.}7MJ{m}^{-3}$

Butene $(C_4{H}_8)=105\mathrm{.}2MJ{m}^{-3}$

Propane $(C_3{H}_8)=85\mathrm{.}8MJ{m}^{-3}$

Air is $21\%$ oxygen, $79\%$ nitrogen by volume and $23\mathrm{.}3\%$ oxygen and

$76\mathrm{.}7\%$ nitrogen by mass.

Atomic mass of $C=12,O=16,N=14$ and $H=1.$