北京化工大学：《化学反应工程》课程PPT教学课件（英文版）Chemical reaction engineering（2011）Chapter 11-15

·The Pulse Experiment Let us find the E curve for a vessel of volume V m3 through which flows v m3/s of fluid.For instantaneously introduce M units of tracer (kg or mole)into the fluid entering the vessel,and record the concentration- time of tracer leaving the vessel.this is the Cpulse curve.From the material balance for the vessel we find 27

27 • The Pulse Experiment • Let us find the E curve for a vessel of volume V m3 through which flows v m3 /s of fluid. For instantaneously introduce M units of tracer (kg or mole) into the fluid entering the vessel, and record the concentration￾time of tracer leaving the vessel. this is the Cpulse curve. From the material balance for the vessel we find

Area under the Cpulse curve A=Cdh=∑C,M=y M kg Mean of the ∑C,At V [Cdr ∑C,Ai [s] Cpulse curve .To find E curve from Cpulse curve simply change the concentration scale such that the area under the curve is unity.Thus simply divide the concentration reading by M/v. E= Cpulse M/v 28

28 • To find E curve from Cpulse curve simply change the concentration scale such that the area under the curve is unity. Thus simply divide the concentration reading by M/v. s v V C t t C t Cdt tCdt t s m k g v M A Cdt C t i i i i i i i i i =   =                =   =                  0 0 pulse 0 3 pulse C curve Mean of the : C curve Area under the M v C E pulse =

Instantaneously introduce M units of tracer into the fluid entering the vessel Record the leaving traces w/ay esind Evaluate the area under the curve Area= Cdt=ΣC:A1 我味→time,S v,m3/s Evaluate the mean i=ficdr=SuCiAn -V=vessel volume JCdt ΣC;At Figure 11.8 The useful information obtainable from the pulse trace experiment

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Area= M asind 道 Area=1 Figure 11.9 Transforming an experimental Cpulse curve into an E curve. We have another RTD function E2,Here time is measured in terms of mean residence time 0=t/t 4= M Eo=tE= y M/y M 1= 30

30 • We have another RTD function , Here time is measured in terms of mean residence time . E  = t t pulse pulse C M V M v C v V E = tE = =             = = v V t v M A

Area=1 Area =1 E 0= E f0=1 Figure 11.10 Transforming an E curve into an Ee curve. 31

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