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Page 1

Lurgi MegaMethanol®

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Lurgi MegaMethanol®

Lurgi�s�MegaMethanol�process�is�an�advanced�technology
for�converting�natural�gas�to�methanol�at�low�cost�in�large�
quantities.�It�permits�the�construction�of�highly�efficient�
single-train�plants�of�at�least�double�the�capacity�of�those
built�to�date.
This�paves�the�way�for�new�downstream�industries�like
Lurgi�s�MTPfi process�which�can�use�methanol�as�a�com�-
petitive�feedstock.

The MegaMethanol Concept
The�Lurgi�MegaMethanolfi technology�has�been�developed
for�world-scale�methanol�plants�with�capacities�greater�than
one million metric tons per year. To achieve such a capacity,
a special process design is needed, incorporating advanced
but�proven�and�reliable�technology,�cost-optimised�energy
efficiency,�low�environmental�impact�and�low�investment
cost.�
The�main�process�features�to�achieve�these�targets�are:
� Oxygen-blown�natural�gas�reforming,�either�in�combina-

tion�with�steam�reforming,�or�as�pure�autothermal
reforming.

� Two-step�methanol�synthesis�in�water-�and�gas-cooled
reactors�operating�along�the�optimum�reaction�route.

� Adjustment�of�syngas�composition�by�hydrogen�recycle.

Synthesis Gas Production
The�synthesis�gas�production�section�accounts�for�more
than�50%�of�the�capital�cost�of�a�methanol�plant.�Thus,
optimisation�of�this�section�yields�a�significant�cost�benefit.

Conventional�steam�reforming�is�economically�applied�in
small and medium-sized methanol plants, with the maximum
single-train capacity being limited to about 3000 mtpd.
Oxygen-blown�natural�gas�reforming,�either�in�combination
with�steam�reforming�or�as�pure�autothermal�reforming,�is
today�considered�to�be�the�best�suited�technology�for�large
syngas�plants.

The�configuration�of�the�reforming�process�mainly�depends
on�the�feedstock�composition�which�may�vary�from�light�
natural gas (nearly 100%methane content) to oil-associated
gases.�The�aim�is�to�generate�an�optimum�synthesis�gas,
characterised�by�the�stoichiometric�number�given�below:�

H2-CO2
CO+CO2

SR= =�2.0���2.1

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Figur_1.eps


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Autothermal Reforming
Pure�autothermal�reforming�can�be�applied�for�syngas�
production�whenever�light�natural�gas�is�available�as�feed-
stock�to�the�process.

The�desulfurised�and�optionally�pre-reformed�feedstock�is
reformed�with�steam�to�synthesis�gas�at�about�40�bar�and
higher�using�oxygen�as�reforming�agent.�The�process�gener-
ates�a�carbon-free�synthesis�gas�and�offers�great�operating
flexibility�over�a�wide�range�to�meet�specific�requirements.
Reformer outlet temperatures are typically in the range
of 950–1050 °C. The synthesis gas is compressed in a single-
casing synthesis gas compressor with integrated recycle
stage�to�the�pressure�required�for�methanol�synthesis.

Even�when�using�pure�methane�as�feedstock�for�autother-
mal�reforming,�it�is�necessary�to�condition�the�synthesis�
gas,�as�its�stoichiometric�number�is�below�2.0.�The�most
economic�way�to�achieve�the�required�gas�composition�is�
to�add�hydrogen,�withdrawn�from�the�methanol�synthesis
purge�stream�by�a�membrane�unit�or�a�pressure�swing
adsorption�(PSA)�unit.

Compared�to�its�competitors,�Lurgi�has�the�most�references
and�experience�for�this�reforming�technology.�This�process
has�been�implemented�in�Lurgi�plants�since�the�1950s.�
Significant�progress�in�optimising�design�and�assuring�plant
availability�was�achieved�at�the�end�of�the�1980s�when�
reliable�simulation�tools�became�available.�

With the help of a proprietary, three-dimensional
Computational�Fluid�Dynamics�(CFD)�model,�gas�flows�and
temperature�profiles�were�simulated�with�the�objective�of
designing�burner�and�reactor�as�an�integrated�unit.

Natural Gas Air

Desulfurization

Pre-reforming

Autothermal
Reforming

Methanol Synthesis

Methanol Distillation

Pure Methanol

Air separation

Hydrogen
Recovery

Oxygen

Fuel Gas

Methanol Production using Lurgi
Autothermal Reforming

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Figur_2.eps


Natural Gas Air

Desulfurization

Steam-reforming

Autothermal
Reforming

Methanol Synthesis

Methanol Distillation

Pure Methanol

Air Separation

Oxygen

Purge
Gas

Process Steam

Methanol Production using
Lurgi Combined Reforming

Combined Reforming
For�heavy�natural�gases�and�oil-associated�gases,�the
required�stoichiometric�number�cannot�be�obtained�by�pure
auto�thermal�reforming,�even�if�all�hydrogen�available�is
recyled.�For�these�applications,�the�Lurgi�MegaMethanol®

concept�combines�autothermal�and�steam�reforming�as�the
most�economic�way�to�generate�synthesis�gas�for�methanol
plants.�After�desulfurisation,�a�feedgas�branch�stream�is
decomposed�in�a�steam�reformer�at�high�pressure�
(35–40�bar)�and�relatively�low�temperature�(700–800°C).
The�reformed�gas�is�then�mixed�with�the�remainder�of�the
feedgas�and�reformed�to�syngas�at�high�pressure�in�the
autothermal�reactor.�This�concept�has�become�known�as
the�Lurgi�Combined�Reforming�Process.

The�main�advantage�of�the�combined�reforming�process
over�similar�process�alternatives�is�the�patented�feedgas
bypass�of�the�steam�reformer.

For�most�natural�gases,�less�than�half�of�the�feedgas�is
routed�through�the�steam�reformer,�the�overall�process
steam requirements also being roughly halved compared
with�other�processes,�which�use�an�autothermal�reformer

downstream�of�the�steam�reformer�without�such�a�bypass.
The lower process steam consumption translates into
reduced�energy�requirements�and�lower�investment.

The Lurgi Combined Reforming Process is also ideal to
generate�synthesis�gas�for�the�Fischer-Tropsch�synthesis.�
The�world‘s�largest�plant�of�this�type�was�built�by�Lurgi�in
South�Africa.�The�synthesis�gas�capacity�of�this�plant�would
be�sufficient�to�produce�about�9,000�mtpd�methanol.

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Figure_3.eps


The first reactor, the isothermal reactor, accomplishes
partial�conversion�of�the�syngas�to�methanol�at�higher
space�velocities�and�higher�temperatures�compared�with
single-stage synthesis reactors. This results in a significant
size reduction�of�the�water-cooled�reactor�compared�to
conventional processes, while the steam raised is available
at a higher�pressure.
The methanol-containing gas leaving the first reactor is
routed to a second downstream reactor without prior
cooling.�In�this�reactor,�cold�feedgas�for�the�first�reactor�is
routed�through�tubes�in�a�countercurrent�flow�with�the
reacting�gas.�Thus,�the�reaction�temperature�is�continuously
reduced�over�the�reaction�path�in�the�second�reactor,�and
the�equilibrium�driving�force�for�methanol�synthesis�main-
tained over the entire catalyst bed. The large inlet gas
preheater normally required for synthesis by a single
water-cooled�reactor�is�replaced�by�a�relatively�small�trim
preheater.

Methanol Synthesis
Efficient�syngas-to-methanol�conversion�is�essential�for�low-
cost�methanol�production.�In�addition,�optimum�utilisation
of�reaction�heat�offers�cost�advantages�and�energy�savings
for�the�overall�plant.�From�the�very�beginning�of�the�low-
pressure�technology�era,�Lurgi�has�equipped�its�methanol
plants�with�a�tubular�reactor�which�transfers�the�heat�of
reaction�to�boiling�water.

The�Lurgi�Methanol�Reactor�is�basically�a�vertical�shell�and
tube�heat�exchanger�with�fixed�tube�sheets.�The�catalyst�is�
accommodated�in�tubes�and�rests�on�a�bed�of�inert�mate-
rial.�The�water/steam�mixture�generated�by�the�heat�of�
reaction�is�drawn�off�below�the�upper�tube�sheet.�Steam
pressure�control�permits�exact�control�of�the�reaction�tem-
perature. This isothermal reactor achieves very high yields
at low recycle ratios and minimizes the production of
by-products.

Based�on�the�Lurgi�Methanol�Reactor�and�the�highly�active
methanol catalyst with its capability to operate at high
space�velocities,�Lurgi�has�recently�developed�a�dual�reactor
system�featuring�higher�efficiency.�The�isothermal�reactor�
is�combined�in�series�with�a�gas-cooled�reactor.

The Lurgi MegaMethanol® Process

Saturated
Steam

PC

LC

Preheated
Syngas

Catalyst
Discharge

Catalyst
Discharge

Start-up
Steam

Catalyst
Support

Boiler
FeedWater

Man-
hole

Syngas Inlet

Product Gas
Outlet

Water-Cooled
Reactor (first reactor)

Gas-Cooled Reactor
(second reactor)

Gas inlet

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Page 6

After�cooling�and�separation�of�the�purge�gas,�the�crude�
methanol�is�processed�in�the�distillation�unit.�In�the�hydro-
gen�recovery�unit,�H2 is�separated�from�the�purge�gas�and
recycled�to�the�syngas�loop.�The�remaining�CH4-rich�gas
fraction�is�used�as�fuel�gas.

The�most�important�advantages�of�the�Combined�Synthesis
Converters�are:
� High�syngas�conversion�efficiency.�At�the�same�
conversion�efficiency,�the�recycle�ratio�is�about�half�of
the�ratio�in�a�single-stage,�water-cooled�reactor.

� High�energy�efficiency.�About�0.8�t�of�50–60�bar�steam
per�ton�of�methanol�can�be�generated�in�the�reactor.�
In�addition,�a�substantial�part�of�the�sensible�heat�can�be
recovered�at�the�gas-cooled�reactor�outlet.

� Low investment cost. The reduction in the catalyst volume
for�the�water-cooled�reactor,�the�omission�of�the�large
feedgas preheater and savings resulting from other
equipment�due�to�the�lower�recycle�ratio�translate�into
specific�cost�savings�of�about�40%�for�the�synthesis�loop.

� High�single-train�capacity.�Single-train�plants�with�capaci-
ties�of�5000�mt/day�and�above�can�be�built.

In�addition,�reaction�control�also�prolongs�the�service�life�
of�the�catalyst�in�the�water-cooled�reactor.�If�the�methanol
yield�in�the�water-cooled�reactor�decreases�as�a�result�of
declining catalyst activity, the temperature in the inlet
section�of�the�gas-cooled�reactor�will�rise�with�a�resulting
improvement in the reaction kinetics and, hence, an increased
yield�in�the�second�reactor.

6

0
240

250

260

270

280

0,2 0,4 0,6 0,8 1

T
e
m

p
e
ra

tu
re

[
C

¡]

Catalyst height
Reaction Cooling water

0
0

100

200

300

0,2 0,4 0,6 0,8 1

T
e
m

p
e
ra

tu
re

[
C

¡]

Catalyst height
Reaction Cooling gas

Water-Cooled Reactor

Temperature Profile Gas-Cooled Reactor

ATLAS MegaMethanol plant

Page 7

Methanol Distillation
The crude methanol is purified in an energy-saving 3-column
distillation�unit.
With the 3-column arrangement, the low boilers are removed
in�the�pre-run�column�and�the�higher�boiling�components
are�separated�in�two�pure�methanol�columns.�The�first�pure
methanol�column�operates�at�elevated�pressure�and�the�
second column at atmospheric pressure. The over�head
vapours of the pressurised column heat the sump of the
atmospheric column. Thus, about 40% of the heating
steam�and,�in�turn,�about�40%�of�the�cooling�capacity�are
saved.�The�split�of�the�refining�column�into�two�columns
allows�for�very�high�single-train�capacities.

Economics of MegaMethanol

Feedstock�cost�and�capital-related�charges�are�the�major�
parameters�for�production�cost.�The�table�beside�illustrates
the�feedstock�consumption,�the�capital�investment�and�the
resulting�production�cost�for�a�conventional�steam�reform-
ing�plant�and�MegaMethanol�plant.�The�results�show�that
the�high�efficiency�of�the�process�and�the�low�capital�invest-
ment�cost�of�a�MegaMethanol�plant�permit�a�significant
reduction of the methanol cost.The resulting long-term,
stable and low methanol prices may pave the way for a
wider�use�of�methanol,�both�in�the�energy�sector�and�as�a
feedstock�in�the�petrochemical�sector.

7

Economics of the MegaMethanol Concept

Conventional MegaMethanol
Steam Reforming Concept

Capacity mtpd 2500 5000

Natural Gas Demand
based on LHV MMBtu/mt 30 28.5

Capex** % 100 130

Opex % 100 97

Production Cost % 100 79

** O2 over the fence

References

Up�to�the�end�of�2009,�Lurgi�has�received�10�contracts�for
MegaMethanol�plants,�with�capacities�ranging�between
0.67�and�2.3�million�tons�per�year.�

Areal view of ATLAS
MegaMethanol plant

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