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.
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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
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