Production of Formaldehyde from Methanol

It is desired to produce about $120,000$ tons$/$year of formaldehyde $(99\mathrm{.}1$ wt$\%)$ and the by$-$product pure nitrogen which originally onsets from the inlet air. Consider the solid$-$catalyzed gas$-$phase conversion of methanol to formaldehyde according to the following reaction:

$,+-02-+$ H$,0$

$-,=4\mathrm{.}762$ x $10-5$ xexp $|-17,630\backslash$times $((-485)]",$

Nevertheless, formaldehyde may undergo complete oxidation:

$+-0->+4,0$

$2\mathrm{.}8246\backslash$times $10-10$ x exp $-8,710\backslash$times $(\}-485)|,$

$-\text{'}=$

$[1+/212,818\mathrm{.}09$ xexp$[-5,290$ x $($f$)]]]$

The catalyst is present in the multitube plug$-$flow reactor with a bed voidage of $0\mathrm{.}5$ and a particle density of $2$ g$/$em$\text{'}.$ The figure below shows the process flowsheet for the solid$-$catalyzed gas$-$phase formaldehyde synthesis from methanol where it is made of the mixer, plug$-$flow reactor, flash unit #$1$ for knocking down water, flash unit #$2$ for substantially striping off N$2,$ and flash unit #$3$ for further separation of HCHO from N$2.$

$$

MOCER?

$3$TOP

PAR

ROCT

$-[-$

Figure I: The flowsheet for the solid$-$catalyzed gas$-$phase formaldehyde synthesis from methanol

Your tasks are as follows:

$"$ Decame ers the roaximizethe conversios of costian of a the selectivy rovade

formaldehyde.

$2.$ Model the formaldehyde production process described above in Aspen HYSYS$/$ Plus.

$3.$ Carry out four sensitivity analyses one for each block, starting from $"$PFR$"$ down to

"FLASH$3"$ block to see the effect of both operating pressure and temperature inside each unit on the mole fraction ratio HCHO$/$CO $($i$.$e$.,$ selectivity$)$ in $"$PRDCT$"$ stream, the mass fraction of HCHO in "FITOP" stream, the mass$-$fraction of N$2$ in $"$F$2$TOP" stream, and the mass$-$fraction of HCHO in "HCHO" stream, respectively.

$4.$ Determine the optimal operating conditions in all units of the process to end up with at least $99\mathrm{.}1$ wt$\%$ pure formaldehyde and $99\mathrm{.}1$ wt$\%$ pure nitrogen at the indicated annual production rate.

$5.$ Plot the composition profile of all the components along the length of the plug flow

on ASPEN PLUS SIMULATION