Chemical Engineering August 2010 - 16

Newsfront
storage (CCS) projects. The
projects would be developed
around GreatPoint Energy's
proprietary Bluegas technology,
which uses catalytic hydromethanation
to generate
H2 and SNG. The process is
more efficient and cost effective
than conventional gasification
routes to SNG, says
GreatPoint Energy's Anthony.
In the Bluegas process (FigCyclone
Feedstock
+ catalyst
CH4
Gas
Sulfur and
ammonia
Particulates
Methane
+
CO2
ure 2), a proprietary catalyst
is dispersed with the feedstock
(coal, petcoke, or biomass), and
the mixture loaded into the reactor.
Pressurized steam is injected
from below to fluidize the
mixture, which reacts to form
CH4, CO, H2 and CO2. The process
operates at about half the
temperature of conventional
coal gasifiers. By performing
the highly endothermic steamreforming
reaction and the
exothermic methanation reactions
in a single reactor, the
overall reaction is thermally neutral,
making the process highly efficient,
says Anthony.
The process has undergone three
levels of pilot testing, most recently
at the company's own pilot plant, the
Mayflower, which handles a nominal
feedrate of 1-3 ton/d, depending on
the feed. The Mayflower is essentially
an exact replica of a commercial system,
just a smaller diameter.
The Bluegas process is competitive
even if gas prices are below $4/
million Btu, says Anthony. Although
today's U.S. prices are around $4-5/
million Btu, they are projected to
reach $6-8/million Btu in the next
ten years, which " is more than high
enough for us, " he says. The first commercial
demonstration - most likely
in China - will have a throughput
of about 700-1,500 ton/d. Once this
is built, it will be quick to duplicate,
says Anthony.
In addition to Peabody Energy, GreatPoint
Energy has three other strategic
partners, The Dow Chemical Co. (Midland,
Mich.; www.dow.com), Suncor
Energy (Calgary; Canada; www.suncor.
com) and AES Corp. (Arlington, Va.;
www.aes.com). All four partners have
invested in the technology, and each
Hydromethanation
Enhanced oil
recovery
Catalyst
recycle
Spent char
removal
Spent char
byproduct
FIGURE 2. GreatPoint Energy's Hydromethanation process directly produces CH4 and
CO2 by the reaction of steam with carbonaceous solids, such as coal, petcoke and biomass
has its own strategic plans for the future
of this emerging technology.
Bio-SNG
While coal-to-SNG technology makes
a comeback in regions where coal is
plentiful, other technologies are being
developed to produce SNG from biomass,
such as wood or straw. These
numerous efforts to make so-called
bio-SNG (or " green gas " ) will not only
lead to applications in coal- and gasscarce
regions, but have the added advantage
over coal-based SNG of being
nearly CO2 neutral - without CO2
capture and storage, says Bram van
der Drift, a process engineer at the
Energy research Center of the Netherlands
(ECN; Petten; www.ecn.nl).
ECN has been developing a biomass
gasification technology, called Milena,
which has a high cold-gas efficiency
and high methane yield, making it
suitable for gas-engine applications.
The product gas can also be upgraded
into SNG. ECN aims to develop largescale
SNG production with 70% energy
efficiency (biomass to bio-SNG),
and sees the gas engine as an application
necessary for reaching large
scale. Together with HVC (Alkmaar,
the Netherlands; www.hvcgroep.com),
16 CHEMICAL ENGINEERING WWW.CHE.COM AUGUST 2010
the Bio-CHP (combined heat and
power) technology is being introduced
on a 10-30-MWth scale.
The Milena gasifier consists of three
parts: a riser, settling chamber and
downcomer. The combustion section
contains a bubbling fluidized-bed combustor
and a sand transporter. Biomass
is fed into the riser, and superheated
steam is added from below. Hot
(925°C) sand or olivine enters the riser
from the combustor and heats the biomass
to 850°C, causing the biomass to
gasify. Hot product gas emerging from
the gasifier enters ECN's " Olga " gascleaning
unit, which removes tars and
dust. Cleaned gas contains mainly CO,
CO2, H2, CH4, and C2H4, and can be
used in gas boilers and gas turbines, or
can be converted into bio-SNG.
Since 2008, ECN has been conducting
pilot trials in an 800-kWth Milena
unit. A 10-MWth demonstration unit
is now being designed, and construction
is planned to start next year at
the HVC facilities in Alkmaar. Several
commercial parties have already
expressed an interest in licensing the
technology, says Van der Drift, and a
50-MWth SNG demonstration plant is
scheduled for startup in 2015.
Uhde is also working on projects
(CO2 sequestration)
Superheated
steam
Source: GreatPoint Energy
Carbon
dioxide
separation
Bluegas
Gas cooling
http://www.ecn.nl http://www.dow.com http://www.suncor http://www.aes.com http://www.hvcgroep.com http://WWW.CHE.COM
Chemical Engineering August 2010

Table of Contents for the Digital Edition of Chemical Engineering August 2010
