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Konversi dalam Reaktor Non-Ideal

T.Kimia ITS2

Contoh-2 : Konversi dg menggunakan data RTD

=

Af

0 A

AA0

X

r

Xd CP

A

AfA0M

r

X C

=

E.dtCCA

CC

element0 AoAo

A

=

XA = 93 %

Reaktor Plug Flow : XA = 99 %

Reaktor Mixed Flow : XA = 82 %

Non ideal, pola alirnya seperti contoh-1 (Levenspiel)

Suatu reaktor (space time = 15 menit) digunakan untuk reaksi dekomposisi dengan laju sbb : -rA = kCA dan k = 0,307 min-1

Tentukan konversi reaksinya jika reaktornya bersifat :a. plug flowb. mixed flowc. tidak ideal, pola alirnya seperti contoh-1

Penyelesaian :

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T.Kimia ITS3

KONVERSI DALAM REAKTOR ALIR NON-IDEAL (model zero parameter)

dtECCA

CC

elementAoAo

A.

=

0( ) dtEXX

elementA .

=

0

Reaksi orde 1 :kt

elementAo

eCCA

=

Reaksi orde 2 :tkCC

CAAoelementAo +

=

11

Reaksi orde n : ( ) nnAoelementAo

ktCnCCA

+=

11111 /)(

T.Kimia ITS4

Contoh-2 :Konversi dg menggunakan data RTD

Waktu t, min 0 5 10 15 20 25 30 35C, g/m3 0 3 5 5 4 2 1 0E=C/area, min-1 0 0,03 0,05 0,05 0,04 0,02 0,01 0e-ktE.t 0 0,0323 0,0116 0,0025 0,0004 0,0001 0,00 0

0,0469tEeCC kt

A0

A== XA = 93 %

E.dteCC

0

kt

Ao

A

=

tE.eCC kt

Ao

A =

E.dtCCA

CC

element0 AoAo

A

=

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Model Dispersi

Adanya dispersi dalam suatu reaktor akan mempengaruhi konversi yang terjadi

Reaksi Kimia & Dispersi

A Produkn

AA kCr =

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Reaksi Orde 1

Untuk deviasi kecil :

Reaksi Orde 1

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Reaksi Orde 2

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Model Tangki Seri

Reaksi Kimia & Tangki Seri

Reaksi Orde 1 : A Produk pada satu tangki :

NNtkN

iA

A

)(1)tk(1CC

+=

+=

110

tk1tk1CC

iA

A

+=

+=

110

Untuk N tangki :

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Reaksi Orde 1

Reaksi Orde 2

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Example 14.1 : MODIFICATIONS TO A WINERY

A small diameter pipe 32 m long runs from the fermentation room of a winery to the bottle filling cellar. Sometimes red wine is pumped through the pipe, sometimes white, and whenever the switch is made from one to the other a small amount of "house blend" rose is produced (8 bottles). Because of some construction in the winery the pipeline length will have to be increased to 50 m. For the same flow rate of wine, how many bottles of rose may we now expect to get each time we switch the flow?

Solutioon :

Figure E14.1 sketches the problem. Let the number of bottles, the spread, be related to .

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Example 14.2 : A FABLE ON RIVER POLLUTION

Last spring our office received complaints of a large fish kill along the Ohio River, indicating that someone had discharged highly toxic material into the river. Our water monitoring stations at Cincinnati and Portsmouth, Ohio (119 miles apart), report that a large slug of phenol is moving down the river, and we strongly suspect that this is the cause of the pollution. The slug took about 10.5 hours to pass the Portsmouth monitoring station, and its concentration peaked at 8:00 A.M. Monday. About 26 hours later the slug peaked at Cincinnati, taking 14 hours to pass this monitoring station. Phenol is used at a number of locations on the Ohio River, and their distance upriver from Cincinnati are as follows:

Ashland , KY-150 miles upstream Marietta, OH-303

Huntington, WV-168 Wheeling, WV-385

Pomeroy, OH-222 Steubenville, OH-425

Parkersburg, WV-290 Pittsburgh, PA-500

What can you say about the probable pollution source?

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SOLUTION

Let us first sketch what is known, as shown in Fig. E14.2. To start, assume that a perfect pulse is injected. Then according to any reasonable flow model, either dispersion or tanks-in-series, we have