cre1 amended

8/12/2019 CRE1 Amended

1/7

Part 1 (a)

From the problem that facing by Dow Chemical Company, here are three main

possible reasons that cause the drop in conversion:

- The condition of Feed

- The troubles cause by the dent of CSTR

- !ista"e that cause error to the reactors and e#uipment$

%$ The condition of feed

The feed plays as a very important role in the reaction$ &hen there are slightly

differences or changes in the condition of feed, it will affect the whole reaction

including the resulting output$

%$% Feed Temperature

, ' ( ) -* C

The e#uation above is the reaction rate constant formula$ The rate constant +r is then

converted into for plotting the graph of inverse of the reaction rate versus

conversion rate $

.+T is the reaction rate constant that depends on the temperature$ Thus, when the

temperature of feed is different it will affect the whole rate constant and thus gives an

impact to the graph$ Too low in feed temperature will cause the drop of rate constant

+", where too high of Feed temperature will give a higher rate constant +"$

&e should chec" whether the heat e/changer of the feed is well function and also the

temperature sensor is giving a proper temperature reading or not$

%$0 Flow rate of feed to CSTR

&hen the flow rate of feed to CSTR is no longer optimi1ed, it will affect the

conversion rate$

's shown on the formula above, when the feed flow rate +F is higher than optimi1ed,the conversion + will drop, when the Feed flow rate +F is lower than optimi1ed, the


2/7

conversion + will rise, which will give a totally different result by comparing the

graph$

&e should chec" the pump of the input feed whether it is giving a correct feed flow

rate and well function or not$

%$2 Feed concentration

)y referring bac" to the reaction rate constant formula, we can deduce that the

concentration of feed +let ' be the feed 3'4 may affect the rate constant +r$

&hen the feed concentration 3'4 is too low, it will decrease the reaction rate +r$

&here too high of feed concentration may also increase the reaction rate +rand cause

the changes in the graph$

&e should chec" the concentration of the feed properly to give an accurate result in

conversion$

0$ The trouble caused by the dent of CSTR$

's stated from the case, a dent was found in the CSTR that may have been caused by

something li"e a for"-lift, the dent may give some changes in the physical propertiesof the reactor, such as the shape, volume and also the condition of the parts of CSTR

reactor such as agitator$

0$% The volume of CSTR

The appearance of the dent has already decrease the volume of CSTR, thus by

referring to the CSTR formula,

&hen the reactor volume +5 decreases, the conversion + will be decreased$

&e should clean the dent and chec" the current volume that the reactor is capable for

+after the formation of dent if there is changes from the actual volume, we should fi/

it to the actual volume$


3/7

0$0 Dead 1ones

's the dent cause dead 1ones to the CSTR reactor, some composition of the feed and

the reactant may trapped inside the CSTR reactor and not flowing out to the 6FR

reactor$

Thus incomplete mi/ing occurs for the whole system, especially by the 6FR$

&e should chec" the concentration of the sample from various location of the CSTR

reactor +include and especially the dent location

0$2 'gitator is bro"en

The dent is formed due to the CSTR reactor is hit by the for"-lift$ 7ence, we can also

assume that these collisions may cause an impact to the condition of the agitator of

the CSTR reactor, for e/ample the agitator is bro"en or loosen from the reactor$

)esides that, the 8woosh9 sound that cause by the CSTR reactor might also actually is

the noisy sound that caused by the bro"en agitator$

Chec" the CSTR agitator will be the only way to define the problem$

2$ 7uman mista"e that cause error to the reactors and e#uipment$!ista"es such as wrongly e#uip or wrongly label of the conversion of 6FR or CSTR

+or both may give false result$

&e should chec" well and double confirmed again the conversion of the 6FR and

CSTR reactor, before we start the reaction$

;f the problem still e/ist, it is force to ta"e a new or another set of the reactor to run

the reaction $


4/7

PART 1(b)

6FR -* CSTR

&here

Since we already "now the first conversion by the 6FR reactor, which is $0%, thus wecan straight proceed to the calculation of CSTR$

)y using trial and error method, with referring to the graph of inversion of rate of

reaction versus conversion :


5/7

< $= ,

$%0 < $> +$=-$$0%


6/7

< $GH,

$%0 < $0H +$GH-$0%

< $%2H +@AT B'E )ut the answer is getting closer

&e can minimi1e the range of into $GII$GH

< $G2,

$%0 < $00H +$G2-$0%

< $%%G

6roved, with


7/7

cre1 amended

Documents