United States
Environmental Protection
Agency
National Risk Management
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/SR-96/006 May 1996
SEPA Project Summary
Hynol Process Engineering:
Process Configuration, Site
Plan, and Equipment Design
Stefan Unnasch
A bench scale methanol production
facility is being constructed to demon-
strate the technical feasibility of pro-
ducing methanol from biomass using
the Hynol process. The plant is being
designed to convert 22.7 kg/h (50 Ib/h)
of biomass to methanol. The biomass
consists of wood, and natural gas is
used as a cofeedstock. Compared with
other methanol production processes,
direct emissions of carbon dioxide
(CO2) can be substantially reduced by
using the Hynol process. This report
covers the design of the hydropyrolysis
reactor system of the Hynol process.
Process flow rates and gas composi-
tions are presented in process flow dia-
grams for the Hynol system and the
hydropyrolysis reactor. Safety, permit-
ting, and site development require-
ments are described for the Hynol
facility. The details of instrumentation
and controls for the hydropyrolysis re-
actor are presented in a piping and
instrumentation diagram. Details of the
equipment design, cost, and schedule
are also documented.
This Project Summary was developed
by EPA's National Risk Management
Research Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented in a separate report of the same
title (see Project Report ordering infor-
mation at back).
Introduction
Producing methanol from biomass of-
fers significant environmental, energy, and
economic advantages over other liquid fuel
resources. Methanol is a clean fuel for
transportation and its widespread avail-
ability will contribute to air quality improve-
ment in most urban areas. Domestic
production of methanol versus imported
fuel supplies brings energy, security, local
jobs, and fuel distribution advantages. Pro-
cess simulation studies indicate that the
Hynol process should result in improved
efficiencies in methanol production through
increased yields over conventional pro-
cesses. The process involves production
from combined use of biomass and natu-
ral gas as feedstocks, optimizing the sto-
ichiometry for synthesis gas to produce
the fuel. The use of biomass feedstock
together with natural gas provides for re-
duced CO2 emissions per unit of fossil
fuel carbon processed compared with
separate natural gas and biomass pro-
cesses.
Production of methanol by the Hynol
process, shown in Figure 1, improves the
overall conversion efficiency compared to
conventional biomass gasification pro-
cesses, which do not use natural gas as a
cofeedstock. Conventional biomass gas-
ification produces a synthesis gas con-
taining excess carbon monoxide (CO),
which must be reacted with steam to form
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Steam Pyrolysis Reactor
Flue Gas
CW
Steam
Figure 1. Hynol process schematic.
Recycle Gas
Methanol
Methanol
Reactor
waste CO2 and hydrogen (H2); otherwise
the H2 yield is insufficient to convert all of
the biomass carbon to methanol. Simi-
larly, when methanol is produced from
natural gas as the sole feedstock, the
resulting synthesis gas contains an ex-
cess of H2 that cannot be converted to
methanol.
Part I. Design Basis, Safety,
and Site Requirements
The Hynol process consists of the hy-
drogenation or hydrolysis of biomass to
produce methane (CH4) followed by the
reaction of CH4 with steam to produce H2
and CO (steam pyrolysis). CO formed in
the steam pyrolysis step is catalytically
combined with H2 in a third step to pro-
duce methanol. Excess H2 is recycled as
a feed gas for hydropyrolysis. Biomass is
fed into the hydropyrolysis reactor (HPR)
and fluidized with recycled H2-rich pro-
cess gas at 30 bar (3000 kPa) and 800°C.
Additional steam can be fed into the HPR
or the steam pyrolysis reactor (SPR). The
independent reactions taking place in the
HPR can be expressed as
C + 2H2 -> CH4
C + H2O -> CO + H2
CO2 + H2
CO + H2O
Before entering the SPR, the process
gas from the HPR is cleaned up to re-
move particulate and impurities that may
contaminate catalysts in the subsequent
reaction steps. Conventional hot gas
clean-up methods can be used for this
purpose. Feed natural gas can be added
prior to the HPR filter to cool the gas
stream and maintain a more filter-friendly
operating environment. Other options in-
clude cooling the gas in a heat exchanger
prior to the hot gas filter.
The process gas is then introduced to
the steam reformer (alternatively called
the SPR) where HPR outlet gas and natu-
ral gas (methane) feed react with steam
to form CO and H2. The steam reforming
can be described by two independent re-
actions:
CH
H20 •
CO2 + H2
-* CO + 3H2
CO + H2O
The reactions take place at 30 bar and
1,000°C. A catalyst-packed tubular exter-
nally fired furnace reactor similar to a con-
ventional natural gas reformer furnace
reactor is used for the SPR. The cooled
process gas is compressed and enters a
conventional methanol synthesis reactor
(MSR). Methanol synthesis occurs at 30
bar and 260°C. Methanol is separated from
water in a condenser and fractionated to
produce concentrated methanol. To in-
crease the conversion of CO in the MSR,
the uncondensed gas from the condenser
is partially returned to the MSR through a
recycle compressor. The remaining por-
tion of gas exiting the MSR is introduced
into a heat exchanger and recycled to the
HPR. The reactions taking place in the
MSR are
CO + 2H2
CO + 3H
CH3OH
» CH3OH + H2O
Facility Overview
The bench scale Hynol facility will be
built at the University of California, River-
side, College of Engineering, Center for
Environmental Research and Technology
(CE-CERT). Acurex Environmental Cor-
poration is working with CE-CERT on fa-
cility design, construction, and operation.
The facility will use biomass (initially white
wood) and natural gas as feedstocks. Af-
ter the facility successfully operates on
wood and natural gas, waste biomass
feedstocks such as tree trimmings will be
used as a cofeedstock. The feedstocks
will be processed into synthesis gas for
methanol conversion.
The facility requires a natural gas com-
pressor, process gas compressor, air com-
pressor, steam generator, and nitrogen
supply. A compressed natural gas (CNG)
fueling station will provide gas for CNG
vehicle fueling and natural gas for the
Hynol plant.
The system will initially operate with the
HPR only, decoupled from the Hynol sys-
tem. The HPR will require an external
source of process gas. The process gas
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that is required for HPR feed contains H2,
CO, CO2, CH4, nitrogen (N2), and water
vapor (H2O). For about 8 months, H2, CO,
CO2, and N2 will be provided on site. Tube
trailers will be parked at the site for the
duration of the test runs (about 2 weeks
each) to provide the H2, CO, and N2. CO2
will be stored as a liquid in high pressure
cylinders. When operating the decoupled
HPR (or HPR and SPR), the process gas
will be burned in a flare. When all three of
the Hynol reactors are operated as an
integrated system, the methanol reactor
will provide the process gas feed to the
HPR.
Various materials will be received,
stored, and shipped from the Hynol facil-
ity. When the facility is not operating, most
materials will continue to be stored on-
site. Ash, sludge, and waste water will be
removed from the site. Methanol will be
removed from the reactor system but will
continue to be stored in the storage tank
to service vehicle requirements. Natural
gas and water will enter the facility via
pipeline. Other materials will be shipped
into and from the facility by truck.
The site plan calls for about 1 acre
(4047 m2), with appropriate grading, fenc-
ing, and landscaping. Precautions will be
taken to deal with safety and environmen-
tal hazards as required. The methanol stor-
age area, for example, would be lined and
bermed to ensure containment of acci-
dental spillage. The site plan identifies
process areas that correspond to equip-
ment on the process flow diagram for the
Hynol system. Different configurations will
apply when the HPR is initially operated
without the other process units.
Part II. HPR System Description
and Hardware
The HPR system demonstrates the
hydropyrolysis of biomass as part of the
Hynol process. Hot H2 and other process
gases are fed into the HPR, where they
react with biomass in a fluidized bed. H2,
CO, and N2 are metered to simulate re-
cycle gas. The gas mixture is heated in a
ceramic heat exchanger and then further
heated with electric heaters. Steam is
added to the gas mixture, and the entire
mixture is heated to 1,000°C. Natural gas
is fed into the system downstream of the
heaters.
The report contains a piping and instru-
mentation diagram for the HPR system.
This diagram shows all of the instrumen-
tation and controls for the HPR system
with the bottled gas feed. Each gas sup-
ply passes sequentially through regulator
pressure indicators and control valves, an
orifice flowmeter, a flow control valve, and
a check valve. Bottled H2, CO, and N2 are
fed from separate or mixed tube trailers or
individual six-packs depending on cost and
feasibility.
The layout for the biomass feed, HPR,
and SPR structure is shown in Figure 2.
The reactor vessels are arranged adja-
cent to each other to minimize pipe runs
and reduce heat losses. The MSR system
is located on a separate structure. The
gasification system structure will be as-
sembled on site. The process reactors will
be delivered and assembled on site. The
report includes design drawings for the
HPR, hot gas filter, water scrubber, and
desulfurization vessel.
Figure 3 shows the configuration of the
HPR. The reactor has a 6-in. (15-cm) in-
ner diameter that is made from refractory
lined pipe in the fluidized section of the
HPR. The freeboard and plenum sections
of the HPR are lined with preformed fiber
insulation. A mixture of hot H2 and other
gases is fed into the bottom of the HPR.
The gases flow through a distributor plate
and fluidize the bed material, which con-
sists of biomass, unreacted char, ash, and
sand that is used for heat transfer and
improved fluidization. Biomass is fed into
the HPR about 1.6 ft (0.5 m) above the
fluidization plate. The top section of the
HPR consists of a larger diameter sec-
tion, which prevents solids carryover. The
gas passes through an internal cyclone
and then proceeds to the hot gas filtration
system.
Figure 2.
The Hynol facility with the methanol synthesis unit in the fore-
ground, compressors in the middle, and the HPR/SPR/feed sys-
tem in the background.
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Figure 3. HPR Reactor vessel and insulation.
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Stefan Unnasch is with Acurex Environmental Corporation, Mountain View, CA
94039.
Robert H. Borgwardt is the EPA Project Officer (see below).
The complete report, entitled "Hynol Process Engineering: Process Configuration,
Site Plan, and Equipment Design," (Order No. PB96-167549; Cost: $47.00,
subject to change) will be available only from
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at
National Risk Management Research Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
National Risk Management
Research Laboratory (G-72)
Cincinnati, OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use
$300
EPA/600/SR-96/006
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