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Lecture

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CEE-Lectures on Industrial Chemistry

• Crystallization as an example of an industrial process (ex. of Ind. Inorg. Chemistry)

� Fundamentals (solubility (thermodynamics), kinetics, principle)� Process design (reactors, processes)� Applications, example: KCl

• Chem. Process Technologies: From raw materials to final products (ex. of Ind. Organic Chemistry

� Fossile resources as raw materials of the chem. industry & energy sources: From the resources to the base materials (general aspects)

� Resources ���� Base materials and selected intermediates• Oil ���� ETHENE and its “family tree”• Oil/nat. gas, coal ���� syngas ���� METHANOL & selected intermediates

� Fine chemicals manufacture

energy – raw material – product-network

Structure of the chemical industry

Source: Moulijn, J.A., Makkee, M., van Diepen, A.: Chemical Process Technology, Wiley 2001

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Simplified scheme of a petrochemical refinery

Aim : production of low molecular organic base chemicals

(D-distillation)

Aromates

1530 14

Butenes8

Pentenes28

≥ C5: Pyrolysis benzine (source for BTX-aromates)

crude oil

atmospheric distillation

decrease H, isomerization, cyclization

700…900 °C

1600…2000 °C

CH4

ethenepropene

(CH4, C2H6, C3H8)

gases

Steam cracking(mid T pyrolysis)

High temperat. pyrolysis

Isolation of aromates

aromates

non-aromates

benzenetoluenexyleneparaffines

C4-separation

Product distribution [wt.-%]

butadieneisobutenen-butenesbutanes

C5-separation

isoprenecyclo-pentadiene

acetylene

pyrolysis benzine

gases

Base materials: production output

Product World 2000/2001 [Mio. t/a]

Germany 2000/2001[Mio. t/a] 2005

Ethene 88.4 4.9 5.4

Propene 45.9 3.5 3.6

Butadiene 7.8 0.7 0.8

Methanol 19.6 (1992) / 32 (1998) / 38.6 (2001)

1.2 (1993)/ 1.9 (2001)/ 2.0 (2005)

Benzene 29.3 2.3

Toluene 13 0.4

Xylenes 24 0.5

Ethine(Acetylene)

0.4 <0.1

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Largest volume chemicals (USA)

Source: Moulijn, J.A., Makkee, M., van Diepen, A.: Chemical Process Technology, Wiley 2001

„Family tree“ of ethene

15 %

8 %

57 %

2 %

10 %

CH3OH + CO

(syngas)PVC: 2. place in world plastics production

Western Europe (2001)

2 %1 %

5 % Others

Main reactions: • catalytic oxidation• addition on the double bond• C-C-coupling reactions

polystyrene

copolymers ABS, SBR

ethylenediamine

copolymers

polyvinyl chloride

polyvinyl acetate

polyvinyl alcohol

styrene

dichloro ethane

vinyl chloride

ethylbenzene

α-olefins

vinyl acetate

ethanol

polyethylene

ethyleneoxid

acetaldehyde

acetic acid

ethylene glycol

ethoxylates

ethanolamine

ethylenecarbonate

alkyl acetatescellulose acetate

acetic anhydride

chloroacetic acid

vinylidene chloride

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Production of synthesis gas

Feedstock

Process

Reaction conditions (reactor, T, cat.)

Reactions

Product ratio(ref. to the main reaction)

Application of syngas

Natural gas Oil Coal

CH4 -CH2- (HC’s) C

Light gasoline fraction

Steam reforming Gasification (partial oxidation)

Heavy fractions (heavy oils, distill. residues)

- Gas heated tube-bundle reactors

- 800 – 900°C (allothermal or partially auto-thermal)

- Catalyst required (Ni)

- Gasification reactors (entrained flow, fluidized bed, fixed bed (moving bed))

- >900°C (autothermal)

- No catalyst

CH4 + H2O ↔ CO + 3H2∆RH = 207 kJ/mol

-CH2- + H2O ↔ CO + 2H2∆RH = 151 kJ/mol

� Autothermal: coupling with partial ox.

-CH2- + ½ O2 ↔ CO + H2∆RH = -92 kJ/mol

(1) C + H2O↔ CO + H2∆RH = 119 kJ/mol

(2) C + ½ O2 ↔ CO∆RH = -113 kJ/mol

� Coupling with “complete” ox.C + O2 ↔ CO2∆RH = -406 kJ/mol

CO : H2 = 1 : 3 CO : H2 = 1 : 2 CO : H2 = 1 : 1

• CH3OH, NH3

• only H2 hydrogenation reactions (refinery), fuel cell…• only CO reduction processes• CO + H2 oxosynthesis, Fischer-Tropsch synthesis

Syngas: mixtures of H2 and CO (small amounts of CH4, CO2)

Gasification

Main reactions of coal gasification

• Reaction of coal with a mixture of air and steam at temperatures > 700 °C

• Main reactions: exoth. combustion + endoth. (heterog.) water gas reaction � autothermal process

• Aims: conversion of coal to gaseous components� Synthesis gas (CO, H2) � Org. intermediates (CH3OH, NH3, aldehydes)

� F-T-Synthesis (Sasol, Shell)� H2 (fuel cell, oil refinery..)

� Reduction gas (CO, H2, CH4) � reduction of ore� “ town gas” / synthetic natural gas (SNG) � heating, power generation

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• Processes:� LURGI Fixed bed 700...1000 °C; 3.5 MPa 39 21 29 11� WINKLER Fluidized bed 850... 950 °C; 0.1 MPa 42 36 20 1� KOPPERS-TOTZEK Entrained-flow 1200...1600 °C; 0.1 MPa 31 58 10 0.1

TEXACO: 4 MPa 35 52 12 0

• Feedstock: bitum. coal, dry brown coal, coke

GasificationEquilibrium composition of synthesis gas as function of T

H2 CO CO2 CH4

H2

CO

CH4

Lurgi - Gasification

Lurgi-gasifier (higher pressure)

(6-40 mm)

(fixed bed/moving bed)

Coal

SteamCoal lock

Drive

Drying

Devolatilization

Gasification

Combustion

Crude gas

Washing/cooling

Dust, tar

Rotating grate

Ash lock

Ash

Distributor

Steam

Oxygen

Drive

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Simplified block diagram of Sasol I Fischer-Tropsch process

(Source: Moulijn, J.A., Makkee, M., van Diepen, A.: Chemical Process Technology, Wiley, Chichester 2001)

Gasification

Raw syngas (cooling)

Cryogenic air separation

Steam

Aqueous phase:Distillation

Syngas purification

F-T synthesis

condensation

Distillation

(CH4, C2H6, unconverted syngas)

syngas

„Coal refinery“

Methanol – flowsheet for methanol production

Crude methanol

Condenser/separator

Cycle gas

Fresh syngas

Heat exchanger

Purge gas (avoiding of increasing inert content)

ReactorDegree of conversion per cycle: 12 - 50 % (f(T, p))

High pressure synthesis:- 1923 BASF- catalyst: ZnO/Cr2O3- T: 360 – 380 °C- p: 25 – 30 MPa(∆RG = +50 kJ/mol)

Low pressure synthesis:- BASF- catalyst: CuO/ZnO/Al2O3- T: 250 °C- p: 5 - 10 MPa(∆RG = +24 kJ/mol)

- Heat extraction:- Quench-reactor- Tube-bundle reactor- Linde-isothermal reactor

Reactor

Catalyst packing

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Principle of the Quench-reactor

Catalyst packing

Fresh syngas

Cycle gas

� Reaction gas is quenched by introducing fresh syngas or cycle gas between the catalyst packings

„saw tooth curve“

Methanol as base chemical• chemical industry (solvent, intermediate)• production of gasoline, olefins and aromates (MTG-, MTO-, MTA-process); fuel cells feed

Acetic acidCH3COOH

Methyl formateHCOOCH3

AlcoholsCH3(CH2)nOH

MTBE(CH3)3COCH3

35 % (1998)

27 % (1998)

Isobutene (HÜLS)

Silicons (grease, resin, rubber)

(solvents)

9 % (1998)

esters

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Oil versus coal

Organic base chemicals produced from oil and coal

High-temperature-pyrolysis

Steam-crackingOlefins

Ethine

Methanol

Aromates

OILReforming

Crack-processes

...

COAL

Motor fuels

Coke

Steam-reforming,Partial Oxidation

Hydrogenation

Plasma-pyrolysis

Carbide synthesis

Carbonization

GasificationSyngas

F-T-Synthesis

Methanol-Synthesis

Mobil-Process

(gasoline, diesel oil...)