Supply

Oxygenates can be produced from both petrochemical and agricultural feedstocks. Methanol, derived primarily from natural gas, is one feedstock used in the production of methyl tertiary butyl ether (MTBE). Ethanol, derived by a fermenting process from corn and other agricultural products, is used either directly as a fuel additive, or as a feedstock for the production of ethyl tertiary butyl ether (ETBE). Isobutylene, which is the other feedstock used in both MTBE and ETBE production, is also derived from natural gas, or as a by-product of petroleum refining.

Production facilities are typically located near feedstock supplies. These may either be in a refinery with butylene from the fluid catalytic unit, or combined with the butylene by-product of a steam cracker. Large-scale MTBE units are based on butane isomerisation/dehydrogenation technology, where both the butane and the methanol are derived from gas sources of low alternative value.



MTBE is still the most widely produced oxygenate. Its raw materials are isobutylene and methanol. An important reason for the widespread use of MTBE is feedstock flexibility. MTBE can be made inside the refinery, using petroleum-derived raw materials, or it can be produced externally, using natural gas feedstocks, thereby ensuring ready availability and reducing dependence on crude oil for the production of automotive fuels.

Isobutylene can be obtained from:
1. steam cracker operation
2. fluid catalytic cracker (FCC) operation
3. butane dehydrogenation
4. dehydration of tertiary butyl alcohol

1. Steam cracker

Steam cracker operations produce isobutylene cost-effectively, but availability is limited. Only a small percentage of the cracker feed is converted into a C4 fraction, the main products being ethylene and propylene. Most of the contained butadiene is extracted and the remaining raffinate-1 is an important source of isobutylene. The premium uses for isobutylene are isobutyl rubber and polyisobutylenes, but it is also an intermediate for a wide range of specialty chemicals. The remainder is mainly used as MTBE feedstock.

More recent technologies convert other C4 components into isobutylene. Notable are the partial hydrogenation of butadiene and the skeletal isomerisation of normal butylenes.

2. FCC

FCC off gases are another source of isobutylene. With the continued requirement for upgrading heavy refinery fractions, more isobutylene is becoming available from this source and a logical use for this stream is an onsite MTBE unit. In Europe there are about fourteen such refinery MTBE units.

3. Butane dehydrogenation

The dehydrogenation route is very capital intensive. Normal-butane needs to be isomerised into isobutane, which is then dehydrogenated into isobutylene. The capital investment for a grassroots 700 kilotonnes/year unit is about 500 million dollars. Most of the current dehydrogenation units are built in areas where infrastructure is already available or in places where raw materials are available at low costs, e.g. the U.S. Gulf Coast, Saudi Arabia, Canada, Malaysia.

4. TBA

Tertiary butyl alcohol (TBA) is produced as a co-product of propylene oxide in dedicated plants. TBA is dehydrated into isobutylene to produce MTBE. It can also be sold directly as an octane-enhancing component for gasoline. Dehydration of TBA is a very cost-effective method of producing MTBE in large quantities.

Production capacity

Commercial production of MTBE started in Europe in 1973 and in the US in 1979. Total worldwide production capacity in 1998 was 23.5 million tonnes and the actual production was 18 million tonnes. The estimated annual production of fuel ethers (MTBE, ETBE, TAME) in the EU today is approximately 5.75 million tonnes.

The distribution of the production capacity for MTBE (and other ether oxygenates) in Europe is shown in the table below. There are more than 50 production plants for ether oxygenates in Europe, some of them swithing from MTBE to ETBE production. The production capacity of the plants ranges from 15,000 tonnes to over 600,000 tonnes per annum and the output of the plants is either used within the company producing the chemical (captive) or is sold on the open market (merchant). 

MTBE, ETBE and TAME Production capacities Europe 2005:

Country

Location

Product

Capacity

(1000 t/a)

Austria

Schwechat

MTBE

65

Belarus

Novopolotsk

MTBE

41

Belgium

Antwerp a

Antwerp b

ETBE

MTBE

183

270

Bulgaria

Bourgas

MTBE

82

Czech Republic

Krapuly

MTBE

92

Finland

Porvoo

Porvoo

ETBE

TAME

94

110

France

Dunkerque

Feyzin

Fos sur Mer

Gonfreville

ETBE

ETBE

ETBE

ETBE

65

84

612

75

Germany

Cologne

Heide

Karlsruhe

Marl

Schwedt

Vohburg

Wesseling

MTBE

MTBE

ETBE

MTBE

TAME

ETBE

MTBE

31

12

163

250

160
37

65

Greece

Aspropyrgos

Corinth

MTBE

MTBE

65

45

Hungary

Szazhalmobatta a

Szazhalmobatta b

Tiszaujvaros

MTBE

ETBE

MTBE

53

55

31

Italy

Gela

Milazzo

Priolo

Ravena

Sannazzaro
Sarroch

MTBE

MTBE

MTBE

ETBE

MTBE
TAME

45

65

41

133

41
237

Lituania

Mazeikiai

MTBE

80

Netherlands

Botlek

Europort

Geleen

Pernis

MTBE

MTBE

ETBE

MTBE

591

98

138

153

Poland

Plock

ETBE

120

Portugal

Sines

ETBE

50

Romania

Midia

Onesti

Pitesti

Ploiesti a

Ploiesti b

MTBE

MTBE

MTBE

MTBE

MTBE

35

100

40

20

25

Serbia

Novi Sad

MTBE

35

Slovakia

Bratislava

ETBE

52

Spain

Algeciras

Bilbao

Huelva

La Coruna

Puertollano

Tarragona a

Tarragona b

ETBE

ETBE

ETBE

ETBE

ETBE

ETBE

ETBE

54

74

50

52

67

54

71 

Sweden

Stennungsund

ETBE

50

Ukraine

Kremenchug

MTBE

24

United Kingdom

Fawley

Grimsby

Killingsholme

MTBE

MTBE

MTBE

122

100

82

Source: LyondellBasell