23greatplainssynfuelsplantanexistingsngplant

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 20
to
138
bars.
 The
acid
gases
are
released
using
a
pressure
swing
or
steam
stripping.
The
Selexol
process
is
more
than
 35
years
old
and
there
are
at
least
55
commercial
units
in
service
(UOP
2008).
In
the
Rectisol
process,
 cold
methanol
is
used
as
an
absorbent
which
absorbs
the
acid
gas
at
a
pressure
of
27.6
to
68.9
bars
and
 at
a
temperature
of
100°
F.
The
Great
Plains
Synfuels
Plant
uses
the
Rectisol
process.
 
 Methanation
 In
the
methanation
reactor,
CO
and
H2
are
converted
to
CH4
and
H2O
in
a
fixed‐bed
catalytic
reactor.
 Since
methanation
is
a
highly
exothermic
reaction,
the
increase
in
temperature
is
controlled
by
recycling
 Climate
Change
Policy
Partnership
 5
 Synthetic
Natural
Gas
(SNG):
Technology,
Environmental
Implications,
and
Economics
 the
product
gas
or
by
using
a
series
of
reactors.
Steam
is
added
to
the
reaction
to
avoid
coke
formation
 in
the
reactor.
After
the
steam
is
removed
from
the
product
gases
by
condensation,
SNG
is
ready
for
 commercial
applications.
 2.1.2.
Hydrogasification
 As
the
name
implies,
the
hydrogasification
process
uses
H2
to
gasify
coal.
H2
reacts
with
coal
to
produce
 CH4.
The
hydrogasification
process
is
exothermic
in
nature.
H2
required
for
the
gasification
is
either
 provided
by
an
external
source
or
by
using
a
methane
steam
reformer.
A
portion
of
the
CH4
generated
in
 the
hydrogasification
reactor
is
converted
into
CO
and
H2
in
the
methane
steam
reformer
(Figure
2).
 
 The
hydrogasification
process
is
in
the
research
stage
and
is
not
yet
commercialized,
although
a
few
 studies
on
the
process
were
conducted
from
the
1970s
to
the
1990s.
Ruby
et
al.
(2008)
have
proposed
a
 hydrogasification
process
which
consists
of
a
hydrogasification
reactor,
desulfurization
and
carbonizer
 reactors
for
CO2
removal,
and
a
methanation
reactor.
The
advantages
of
hydrogasification
will
be
 discussed
in
the
following
section
on
catalytic
steam
gasification.
 
 Coal
 Particulate,
 tar
removal
 
 Coal
 Hydro‐ Gas
 CH4,
H2
 cleaning
 
CO
 gasifier
 
 
 Hydro‐ gasifier
 Ash
 
 Compression
and
 sequestration
(optional)
 Steam
 
 CO2
 
 Steam
 Water‐gas
 
 CO2
 shift
 
 
 Water‐gas
 shift
 
 Gas
 CH4
 separator
 
 (SNG) CH4,
H2
 
CO2
 
 CH4,
H2,
 
CO2
 
 

 SNG
 
 SNG
 CH4 
 CH4
 Methane
 
 Gas
 Gas
 CH4
 
 Steam
 separ(SNG)
 ator
 cleaning
 
 steam
 H2
 CO,
H 
 CO,
H2
 2 
 

 
 Ash
 reformer
 
 
 Steam
 
 CO,
H2
 Figure
2.
Hydrogasification
process
diagram
CO...
View Full Document

This essay was uploaded on 03/18/2014 for the course ENG 316K taught by Professor Kruppa during the Spring '08 term at University of Texas at Austin.

Ask a homework question - tutors are online