Process Intensification for Autothermal Reaction · Process Intensi cation for Autothermal Reaction...

ProcessIntensification

forAutothermal

Reaction

Manal MoftahSaleh

Introduction

Objectives ofthe research

work done sofar

Model equations

The requiredfeed temperaturefor 90 %conversion in R1

Steady-statesolutions

Conclusion

Thanks

Process Intensification for AutothermalReaction

Manal Moftah Saleh

University of Wollongong

November, 2015


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Presentation Outline

1 Introduction

2 Objectives of the research

3 work done so farModel equationsThe required feed temperature for 90 % conversion in R1Steady-state solutions

4 Conclusion

5 Thanks


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Motivation

The world is currently facing critical challenges:

Future energy requirements.

Greenhouse emissions.

Rising oil prices and “peak” oil resources

Possible solutions:

natural gas → syngas → liquid fuels/H2.

Aim: develop mathematical models for autothermal processesto maximize product concentration.


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Models based on CSTR. Advantages are:

Operated continuously.

Reduces running costs.

Relatively easy to maintain temperature control.

Control of the equipment and grade of final product issimplified.

Single or cascade.


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Autothermal reactor

What is an autothermalreactor?


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks


1 Introduction



4 Conclusion

5 Thanks


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Objectives of the research

Investigate the chemical mechanism

AQ1<0−−−→k1

BQ2>0−−−→k2

C·

where ki = ai exp[−EiRTi

]i = 1, 2.

Maximize the product concentration (C ).


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks


1 Introduction



4 Conclusion

5 Thanks


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Diabatic CSTR

A diabatic process is a process that occurs with the transfer ofheat between a system and its surroundings.

T1,Catalyst 1 T2,Catalyst 2- - -

T(a,1) T(a,2)

q,T0,A0 A2,B2,C2A1,B1


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Characteristic Temperature Tc

Normally reaction terms written as

a exp

[E

RT

].

The pre-exponential factor in the studied model is written as

a =Eα

RT 2c

exp

[E

RTc

].


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Dimensional model equations: Reactor one

Concentration of reactant A

V1dA1

dt= q(A0 − A1)− V1a1 exp

[−E1

RT1

]A1. (1)

Concentration of intermediate B

V1dB1

dt= q(B0 − B1) + V1a1 exp

[−E1

RT1

]A1. (2)

Concentration of product C

V1dC1

dt= q(C0 − C1) + 0. (3)


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Temperature inside the reactor

cpgρgV1dT1

dt= qcpgρg (T0 − T1) -Q1V1a1 exp

[−E1

RT1

]A1

− J1χ1S1(T1 − Ta,1). (4)

The pre-exponential factor

a1 =E1α

RT 2c1

exp

[E1

RTc1

]. (5)


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Reactor two:

Concentration of reactant A

V2dA2

dt= q(A1 − A2) + 0. (6)

Concentration of reactant B

V2dB2

dt= q(B1 − B2)− V2a2 exp

[−E2

RT2

]B2. (7)

Concentration of reactant C

V2dC2

dt= q(C1 − C2) + V2a2 exp

[−E2

RT2

]B2. (8)


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Temperature inside the reactor

cpgρgV2dT2

dt= qcpgρg (T1 − T2)+Q2V2a2 exp

[−E2

RT2

]B2

− J2χ2S2(T2 − Ta,2). (9)

The pre-exponential factor

a2 =E2α

RT 2c2

exp

[E2

RTc2

]. (10)


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

A∗1 = 0.1

(a) Q1 = 205.8(KJ mol−1) (b) Q1 = 100(KJ mol−1)


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Steady-state diagrams (A∗1 = 0.1)

(c) Tc2 = 405(K). (d) Tc2 = 435(K).


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks (e) Tc2 = 442(K). (f) Tc2 = 448(K).


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks (g) Tc2 = 464(K). (h) Tc2 = 511(K).


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

LP unfolding diagram


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

The key idea

90 % conversion (C ∗2 = 0.9).

A∗1 < 0.1.

Six steady-state diagrams.

LPig < 298(K)

LP unfolding diagram.


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks


1 Introduction



4 Conclusion

5 Thanks


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Conclusion

Reaction occurring in two reactors: endothermic in R1and exothermic in R2.

high conversion in R1 (low endothermicity).

Steady-state solutions.

Interesting results.


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks


1 Introduction



4 Conclusion

5 Thanks


forAutothermal

Reaction

Manal MoftahSaleh

Introduction


work done sofar

Model equations



Conclusion

Thanks

Acknowledgment

Libyan government through the awarding of a PhDscholarship.

Assoc Prof. Mark I Nelson and co-supervisors.

My family (husband) for preceding help and suitableenvironment.

The organiser of NSW ANZIAM meeting.

Process Intensification for Autothermal Reaction · Process Intensi cation for Autothermal Reaction...

Documents

Transcript of Process Intensification for Autothermal Reaction · Process Intensi cation for Autothermal Reaction...