ice 204 chp1 introduction

ICE 204 – KINETIKA & KATALISIS

I. PENDAHULUAN

I.1 Teknik reaksi kimia (kinetika, katalisis, dan

perancangan reaktor) sebagai salah satu inti

ilmu TK

I.2 Kinetika reaksi kimia

I.3 Katalisis

II. TERMODINAMIKA REAKSI KIMIA

II.1 Kesetimbangan reaksi kimia

II.2 Kespontanan reaksi

II.3 Pengaruh kondisi reaksi (T,P) terhadap

kesetimbangan

II.4 Konversi maksimum (kesetimbangan)

III. KINETIKA REAKSI HOMOGEN TANPA KATALIS

III.1 Laju, orde, konstanta laju, dan mekanisme

reaksi kimia

III.2 Pengaruh T terhadap laju reaksi

III.3 Laju reaksi sederhana : reaksi satu arah

dengan reaktan tunggal dan jamak

III.4 Reaksi bolak-balik

III.5 Reaksi kompleks : seri, paralel, dan seri-

paralel

IV. PERCOBAAN DAN ANALISIS DATA

IV.1 Aspek-aspek eksperimen kinetika reaksi

IV.2 Metode interpretasi data kinetika

IV.3 Metode diferensial

IV.4 Metode integral

V. KATALIS & KATALISIS

V.1 Katalis & katalisis dalam reaksi kimia

V.2 Klasifikasi katalis

V.3 Katalis homogen dan heterogen

VI. KATALISIS DALAM INDUSTRI

VI.1 Katalis dalam industri

VI.2 Katalis padat

VI.3 Katalis industri homogen

VI.4 Katalis industri heterogen

VI.5 Paper project :

A. Katalisis dalam kilang minyak dan

industri petrokimia: Hydrotreating,

Gasoline production, Olefins

B. Katalisis dalam produksi amoniak

VII. KINETIKA REAKSI BERKATALIS HOMOGEN

VIII. KINETIKA REAKSI BERKATALIS HETEROGEN

NOTES:

1. JUMLAH MINGGU PERKULIAHAN = 13 - 14

2. ABSENSI MINIMUM (SYARAT WD 1) = 80%

3. PERKIRAAN BOBOT PENILAIAN :

QUIZ / TUGAS = 20%

UTS = 40%

UAS = 40%

4. BUKU PEGANGAN :

i. Ronald W. Missen, Charles A, Mims, & Bradley A. Saville.

Introduction to Chemical Reaction Engineering & Kinetics. John

Wiley & Sons, 1999 – CD

ii. J. M. Smith. Chemical Engineering Kinetics. 3rd Edition, Mc-

Graw-Hill, 1981

iii. Charles G. Hill Jr. An Introduction to Chemical Engineering

Kinetics & Reactor Design, John Wiley & Sons, 1977

5. BUKU RUJUKAN / PELENGKAP :

i. I. Chorkendorff, J.W. Niemantsverdriet. Concepts of Modern

Catalysis and Kinetics. 2nd Edition, Wiley-VCH, 2007 – CD

ii. Jens Hagen. Industrial Catalysis. 2nd Edition, Wiley-VCH, 2006

iii. Nicolas P. Chopey. Handbook of Chemical Engineering

Calculations. 3rd Edition, Chapter 5 Reaction Kinetics & Reactor

Design – CD

iv. Robert H. Perry. Handbook of Chemical Engineers. 7th Edition,

Section 7 Reaction Kinetics – CD

v. Margaret Robson Wright. An Introduction to Chemical Kinetics.

John Wiley & Sons, 2004 – CD

6. e-Learning : http://elearning.unpar.ac.id berisi

slide2 kuliah, tugas, pengumuman, dll. Diupdate

tiap minggu. Enrolment key & sign up!

http://elearning.unpar.ac.id/

ICE 204 KINETIKA & KATALISIS – CHAPTER 1

CHP 1 - INTRODUCTION

This section covers the definition of chemical kinetics and

catalysis and their linkage with other core chemical

engineering courses

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1.1 Chemical kinetics is the study of the rate

and mechanism by which one chemical

species is converted to another.

Rate [=] mass (moles) of a reactant consumed or a

product produced per unit time (rate is normally per

unit volume of reaction mixture – homogeneous

reactions OR per unit mass of catalyst –

heterogeneous fluid-solid reactions).

Mechanism is the sequence of individual chemical

events whose overall-result produces the observed

reactions.

2 NO + 2 H2 N2 + 2 H2O

the steps of reaction :

2 NO + H2 N2 + H2O2

H2O2 + H2 2 H2O

However, to design a reactor the reaction

mechanism is NOT necessary.

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1.2 Catalysis is all processes in which the

rate of a reaction is influenced by a

substance that remains chemically

unchanged. The catalysis material does

take part in the reaction, however, it

remains unchanged at the end of the

reaction.

Source : Concepts of Modern Catalysis and Kinetics

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Why catalysts are VERY important? (Concepts of

Modern Catalysis and Kinetics)

• around 90% industrial reactions use catalysts

• catalysts make reactions proceed much faster and

milder conditions (lower T & P) can be used

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• catalysts direct and control reactions: speed up the

desirable reaction and at the same time slow down

unwanted reactions.

PBA →+ (desirable)

QA → (side reaction)

for reactions without any catalysts presence: choose a correct

type of reactor and/or reaction conditions so that rP >> rQ.

most of industrial reactions are catalytic; directing reaction to

be selective for main product is one of the main features of a

catalyst!! Therefore, a proper or suitable catalyst needs to be

designed and used for a specific reaction.

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Source : Fogler, Elements of Chemical Reaction Engineering

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1.3 Tasks to be addressed by a chemical

engineer regarding chemical reactions:

A. Determine whether a reaction is thermodynamically

and economically feasible – a reaction may be either

thermodynamically possible (ΔG < 0) OR not (ΔG > 0)

at a certain condition (P, T). In addition, ΔGo (Po = 1

atm) may be the first indication of economical

feasibility of a reaction. ΔGo is also useful for

predicting the maximum (equilibrium) conversion.

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B. Design reactor type and dimension – space time

(how long the reaction mixture should be placed or

flowing inside the reactor).

C. Determine reactor construction-materials – reaction

mixture nature and conditions (P, T).

Source : Subagyo, Slide Kuliah “Kinetika & Katalisis “ – Reaktor-reaktor Industrial


TTHHEERRMMOODDYYNNAAMMIICCSS

TTRRAANNSSPPOORRTT PPHHEENNOOMMEENNAA

spontaneous

((mmaassss,, eenneerrggyy,, mmoommeennttuumm))

CCHHEEMMIICCAALL KKIINNEETTIICCSS

kinetic exp: intrinsic kinetic

CCHHEEMMIICCAALL RREEAACCTTOORR DDEESSIIGGNN

X max

Intrinsic kinetics Space time

Catalytic aspects (selectivity, deactivation,

amount) Δ H (+ / -)

Scale up Heterogeneous-

catalytic reactions

Other Chem Eng CORE subjects: Mass & energy balances Separation processes (OTK III

& IV) Fluid mechanics (OTK I) Heat transfer (OTK II)

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Intrinsic kinetic means the chemical species change rates

are ONLY dependent on the chemical transformation

process and not affected by other (possible & influencing)

physical effects.

Reliable correlations for most mass and energy transfer

are usually available, however, intrinsic kinetics are

ALWAYS obtained from experiments.

Possible influencing physical effects: mass transfer

limitations (diffusion), the degree of mixing, non-

isothermallity. In a catalytic heterogeneous reaction, the

intrinsic kinetic determination is a rather complex

problem, because the rate of physical (diffusion) effects

must be minimized and much smaller than the reaction.

Therefore, to minimize these physical effects, intrinsic

kinetic determinations are normally carried out in a small

laboratory scale reactors (either batch or continuous).

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1.4 SCALE-UP COMMERCIAL REACTORS (Smith, Chemical Eng Kinetics)

LAB SCALE REACTORS

LLAARRGGEE SSCCAALLEE IINNDDUUSSTTRRIIAALL RREEAACCTTOORRSS

PPIILLOOTT SSCCAALLEE RREEAACCTTOORRSS

Intrinsic rate

intrinsic rate +

influence of the physical

steps (depends on the reactor type chosen) Significance of

physical processes is minimized

Operated at near isothermal

1) Physical resistances are directly projected to a large reactor unit

2) The large reactor should have the same inter-relationship of chemical & physical process > reactor dimensions & operating conditions must be similar as in the pilot scale reactor

3) Scale-up will be easier if exactly the same type of reactor is used for lab & commercial applications – pilot scale may be omitted unless an integrated pilot plant is necessary to build

4) 3 types of diffusional effects need to be considered for scaling up heterogeneous reactors (eg. fixed bed reactor): mixing characteristics, cohesion between the fluid (gas or liquid) and solid catalyst, internal diffusion

Miniature of REAL industrial reactors

Particular reactor type is chosen

Operating conditions are chosen

Economic considerations

Hardly isothermal

SCALE-UP – see the illustration at next page

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ice 204 chp1 introduction

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