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METHANOL FROM WOOD WASTE $0.77/gal 1977 TECHNICAL AND ECONOMIC STUDY
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METHANOL FROM WOOD WASTE: A Technical and Economic Study
By A. E. HOKANSON and R. M. ROWELL June 1977
Forest Products Laboratory Forest Service U. S. Department of Agriculture USDA Forest Service
General Technical Report FPL 12 ABSTRACT

A methanol-from-wood waste facility having a capacity of 50 million
gallons per year requires 1,500 ovendry tons (ODT) of wood waste per day.

The yield of methanol from wood is about 38 percent, or about 100 gallons
per ODT of wood.
This yield is based on all process energy required
coming from the wood waste.


At a wood waste cost of $15/ODT, the selling price of methanol is estimated at $0.77/gal; at $34/ODT, the selling p r i c e i s $ 0 . 9 6 / g a l .


METHANOL FROM WOOD WASTE: A TECHNICAL AND ECONOMIC STUDY
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr12.pdf
By
A. E. HOKANSON, Raphael Katzen Associates
Consulting Engineers
Cincinnati, Ohio
and
R. M. ROWELL, Research Specialist
Forest Products Laboratory,I Forest Service
U. S. Department of Agriculture
INTRODUCTION
To reduce petroleum consumption in the United States, one proposal is to
blend 10 to 15 percent of methyl alcohol (methanol) in gasoline for
a u t o m o t i v e u s e .2 / At a current consumption rate of 110 billion gallons
per year (gpy), 11 billion gallons of methanol would be required. At
p r e s e n t , m e t h a n o l c a p a c i t y i n t h e U n i t e d S t a t e s t o t a l s 1 . 2 b i l l i o n g p y ,
of which 99 percent is petroleum-derived, e i t h e r f r o m n a t u r a l g a s o r
from refinery light-gas streams. To increase methanol production, recommendations
have been made to use other sources of carbon for synthesis
of methanol. The Forest Service, in cooperation with the National
Science Foundation, and the Federal Energy Administration, conducted a
technical and economic feasibility study for producing methanol from
wood waste.
Methanol Production Today
Methanol is produced synthetically from carbon monoxide (CO) and hydrog
e n ( H2). I n a c a t a l y s t - f i l l e d c o n v e r t e r o p e r a t i n g a t p r e s s u r e s r a n g i n g
1/ Maintained at Madison, Wis., in cooperation with the University
of Wisconsin.
2/ Reed, T. B., and R. M. Lerner. 1973. Methanol: A versatile
fuel for immediate use. Sci. 182 (4119):1299-1304. (Dec. 28.)
from 1,500 to 4,000 pounds per square inch (lb/in.2 ) two volumes of hydrogen
to one volume of carbon monoxide react to form a crude methanol which is
r e f i n e d . In 'today's methanol plants, natural gas, consisting primarily
of methane, is steam-reformed catalytically into CO and H2 . A small
amount of carbon dioxide is added to the methane to permit part of the
hydrogen to form additional CO so that the final gas product contains
two volumes of H2 to one volume of CO. These reactions are:
3CH4 + CO2 + 2H2O 8H2 + 4 CO
8 H2 + 4 CO 4 CH3OH
Methanol From Wood Waste
Any carbonaceous material such as coal, lignite, wood waste, agricultural
r e s i d u e , and garbage can be utilized for synthetic methanol production.
However, i n c o n t r a s t t o n a t u r a l g a s , t h e s e r a w m a t e r i a l s r e q u i r e s e v e r a l
a d d i t i o n a l p r o c e s s i n g s t e p s t o r e f i n e t h e c r u d e g a s p r o d u c t i n t o a f i n a l
clean gas product (syngas) consisting of two parts of H2 t o o n e p a r t o f C O .
A s a r e s u l t , the conversion of a carbonaceous material is considerably more
e n e r g y - i n t e n s i v e t h a n t h a t r e q u i r e d b y n a t u r a l g a s . I t s l o g i s t i c s a r e
c o n s i d e r a b l y g r e a t e r ( s o l i d s h a n d l i n g v s . p i p e l i n e ) . I t s y i e l d i s l e s s .
A schematic drawing of the overall process steps for converting wood waste
into methanol is shown in figure 1.
GASIFIERS
For any solid carbonaceous material to be converted into a syngas, it is
f i r s t n e c e s s a r y t o p a r t i a l l y b u r n o r o x i d i z e t h e m a t e r i a l t o p r o d u c e a c r u d e
gas consisting primarily of H2, CO, and CO2 . I f a i r i s u s e d t o o x i d i z e
t h e f e e d m a t e r i a l , the crude gas contains about 46 percent nitrogen, which
can be removed by cryogenic means. I f o x y g e n i s u s e d i n s t e a d o f a i r , a
cryogenic system is required f o r i n i t i a l s e p a r a t i o n o f a i r i n t o o x y g e n
and nitrogen.
S e v e r a l t y p e s o f g a s i f i e r s h a v e b e e n d e v e l o p e d f o r t h e p a r t i a l o x i d a t i o n
of wood, wood waste, and garbage. These are designed to operate at atmosp
h e r i c p r e s s u r e , i n c o n t r a s t t o c o a l g a s i f i e r s w h i c h c a n o p e r a t e a t p r e s s u r e s
2 u p t o 4 0 0 l b / i n . g . Gasifiers produce a crude gas consisting primarily of
H2, CO, and CO2 with minor amounts of heavier hydrocarbons. Also, about
2 p e r c e n t o f t h e w o o d ( d r y b a s i s ) i s c o n v e r t e d t o a n o i l - t a r f r a c t i o n .
A comparison of the crude gas from two types of gasifiers is shown in table 1.
- 2 -
Process Steps
1. P a r t i a l o x i d a t i o n o f
wood waste.
2. Clean and cool crude gas.
2
3. Compress to 100 lb/in. g.
4 . Remove carbon dioxide.
5 . Remove residual carbon
dioxide.
6. Remove nitrogen and
hydrocarbons.
7. 2 Compress to 400 lb/in. g.
8 . Shift gas to two parts
hydrogen and one part
carbon monoxide.
9. Remove carbon dioxide
formed in shift.
2
10. Compress to 2,500 lb/in. g.
11. Convert hydrogen and carbon
monoxide into methanol.
12. Refine crude methanol into
specification grade product.
Figure 1. --Methanol synthesis from wood waste.
- 3 -
Table l.--Comparative crude gas compositions
Raw gas Moore-Canada UCC Purox
(dry basis) (wood waste) (garbage)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Hydrogen
V o l . i n p c t V o l . i n p c t
18.3 26.0
Carbon monoxide 22.8 40.0
Carbon dioxide 9.2 23.0
Methane 2.5 5 . 0
Hydrocarbon 0.9 5.0
Oxygen 0.5 0.5
Nitrogen 45.8 0.5
100.0 100.0
- 4 -
Although the feed material for the UCC Purox reactor is garbage, it is
expected that the crude gas composition will be essentially the same for
wood waste because garbage has been found to have practically the same
composition with regard to carbon, hydrogen, and oxygen.
Purox
Under the name "Purox," Union Carbide has developed a process for the partial
o x i d a t i o n o f " a s - i s " garbage using oxygen3 /. The reactor-gasifier employs
a moving bed in which oxygen is passed countercurrent to the downflowing
r e s i d u e . A s t h e m a t e r i a l f l o w s t h r o u g h t h e r e a c t o r , i t p a s s e s s u c c e s s i v e l y
through stages of drying, reduction, and oxidation; at the bottom, ash
is removed in molten form at a temperature of about 3,000° F. Crude gas
containing a large amount of moisture leaves the top at a temperature of
about 200° F.
Development work was initiated by Union Carbide in 1970, in a pilot plant
sized for a feed rate of 2.5 ODT/D (ovendry tons per day) of garbage.
In 1974, a demonstration plant using a lo-foot-diameter reactor, having
a capacity of 150 ODT/D of garbage, was put into operation. Scaleup of
t h e r e a c t o r t o t h i s l e v e l r e s u l t e d i n a s i g n i f i c a n t d e c r e a s e o f c o n v e r s i o n
e f f i c i e n c y , as evidenced by an increase in carbon dioxide and hydrocarbon
l e v e l s i n t h e r a w g a s .
An important factor in the performance of any moving bed reactor is the
s t a b i l i t y o f t h e b e d . Stability apparently decreases with increasing diameter.
The diameter limitation has been demonstrated in the gasification of coal
by the Lurgi Process. Lurgi has succeeded in operating a reactor 11.7 feet
( f t ) i n d i a m e t e r , b u t f a i l e d t o p u t i n t o o p e r a t i o n a r e a c t o r o f 1 3 . 7 f t .
This casts some doubt on the possibility of further scaleup of the Purox
reactor beyond 12 ft, even if its performance on wood waste was demonstrated
to be superior to that of garbage.
M o o r e - C a n a d a
Moore-Canada of Richmond, British Columbia has developed, over the past
two years, a moving bed reactor for producing a low Btu gas from "as-is"
wood waste. In contrast to Purox, the Moore reactor relies on the use
of air as the oxidizing medium. Because of the high nitrogen content,
the raw gas has a heating value of about 180 Btu per standard cubic foot
( s c f ) , i n c o n t r a s t t o t h a t o f t h e h e a t i n g v a l u e o f t h e P u r o x u n i t o f 3 5 0 B t u /
s c f .
3/ Anderson, J. E. 1973. Solid refuse disposal process and
a p p a r a t u s . Patent No. 3,729,298. April 24.
- 5 -
Currently a semi-works unit is in operation. T h i s u n i t h a s a 5 . 5 - f t - d i a m e t e r
gasifier with a capacity of about 18 ODT/D of wood waste. A commercial
i n s t a l l a t i o n i s b e i n g p u t i n t o o p e r a t i o n i n m i d - 1 9 7 6 . T h i s f a c i l i t y u t i l i z e s
t w o 9 . 5 - f t - d i a m e t e r r e a c t o r s , each capable of processing 60 ODT/D of hogged
wood waste.
Operation of the Moore reactor is similar to Purox in that the feed material
enters at the top and the wood ash is discharged from the bottom. However,
because air rather than oxygen is used, the maximum temperature of the
oxidation (lower) zone is only about 2,200° F; waste is discharged as a
solid in a granular form rather than as a molten slag. P r e s s u r e a t t h e
base of the reactor is approximately 6-8 lb/in.2g and at the top 2-3 lb/in.2 g.
The raw gas leaves the reactor at a temperature of 160° or 180° F. By
a d d i n g s t e a m t o t h e a i r , the hydrogen content of the crude gas from the
Moore reactor-gasifier is increased from 8-10 percent to 18-22 percent.
Other Gasifier Designs
B a t t e l l e .--The Battelle Pacific Northwest Laboratories carried out a 1-year
p i l o t p l a n t s t u d y o n t h e p a r t i a l o x i d a t i o n o f m u n i c i p a l r e f u s e i n a 3 - f t
(inside diameter) moving bed reactor pilot plant 4 / . This study also included
p a r t i a l o x i d a t i o n o f w o o d c h i p s u s i n g a i r a n d s t e a m , w i t h r e s u l t s t h a t
approximated those reported by Moore-Canada.
Thermex. --A 50 ODT/D demonstration plant for the gasification of wood waste
has been put into operation in Edmonton, Alberta, Canada, by Alberta Industrial
Development, Ltd. Under its present mode of operation, it produces a char
and a low-Btu gas, but it is understood that it can be designed to operate
without forming char. T h e g a s i f i e r i s a f l u i d i z e d - b e d t y p e r e q u i r i n g t h a t
the wood waste feed be hammermilled to less than 2-in. particle size.
No data are available at this time regarding gas composition.
Copeland. --The Copeland organization has built, over the past 15 years,
a number of fluidized-bed reactors for the pulp industry for disposal of
t h e o r g a n i c m a t t e r i n w a s t e l i q u o r . Such a unit would be able to accept
" a s - i s " w o o d w a s t e a n d s l u d g e , b u t i t s a p p l i c a b i l i t y t o p a r t i a l o x i d a t i o n
for syngas has not been investigated.
a t 3 0 0 - 4 0 0 l b / i n . g . I t c a n h a n d l e o n l y n o n c a k i n g t y p e c o a l , u t i l i z i n g
a p a r t i c l e s i z e r a n g e f r o m 3 / 8 t o 2 i n . A t t h i s t i m e , no attempt has been
made to process wood waste in a Lurgi reactor. T h e r e a c t o r r e q u i r e s r e l a t i v e l y
uniform particle size and would not be expected to handle wood waste.
L u r g i . --The Lurgi reactor is designed to gasify coal with oxygen and steam
2 5 /
4/ Hammond, V. L. 1972. P y r o l y s i s - i n c i n e r a t i o n p r o c e s s f o r s o l i d
waste disposal. Battelle Pacific Northwest Laboratories, Richland, Wash.
December.
5/ Maddox, R. N., ed. 1975. Energy Communications 1(5):433-494.
- 6 -
Winkler.-- The Winkler unit is a fluidized bed coal gasifier operating at
o r n e a r a t m o s p h e r i c p r e s s u r5e/ . T h e s e g a s i f i e r s a r e t y p i c a l l y 1 8 f t i n
diameter and operate at a temperature of about 2,200° F. Coal fed to the
Winkler is ground to less than 1/4 in. No attempt has been made to apply
the Winkler gasifier to wood waste, nor does it appear to offer promise
i n t h i s a r e a s i n c e p a r t i c l e s i z e i s l i m i t i n g .
Koppers-Totzek.--These units process pulverized coal with steam and oxygen
under slagging conditions at atmospheric pressure at temperatures up to
3,500° F5 /. Although about 16 Koppers-Totzek installations have been built,
employing a total of about 40 gasifiers, t h i s t y p e g a s i f i e r i s n o t d e e m e d
practical for the handling of wood waste because of requirements for finely
ground feed.
O n t h e b a s i s o f c u r r e n t l y a v a i l a b l e d a t a , the Moore-Canada gasification
system was judged to be the most promising and, therefore, was adopted
a s t h e b a s i s f o r t h i s s t u d y . The material balance for the Moore-Canada
is shown in tables 2 and 3.
GAS PURIFICATION
Crude gas from partial oxidation units is processed to remove water vapor,
t a r s , o r g a n i c s , hydrocarbons, nitrogen, and CO2. The clean gas, containing
primarily H2 a n d C O , i s t h e n p r o c e s s e d i n a s h i f t r e a c t o r t o r e a c t p a r t
of the CO to form additional H
2
, s o t h e f i n a l g a s c o n t a i n s t h e p r o p e r r a t i o
of 2:1 of H2 and CO. In the shift reactor, additional CO2 is formed, thus
making it necessary to again s c r u b t h e g a s b e f o r e t h e s y n t h e s i s r e a c t o r .
Crude gas from the gasifiers passes upward in the single cooler-absorberscrubber,
cooling the gas from about 180° to 90° F in three stages of cont
a c t i n g ( f i g . 1 , s t e p 2 ) . I n t h e l o w e r t w o s t a g e s , c o o l e d , r e c i r c u l a t e d
liquor streams contact the crude gas. In the upper stage, reclaimed water
condensate is used to complete the removal of organic compounds such as
a c e t i c a c i d .
Because the moisture condensed from the crude gas (roughly equal in weight
to the dry wood substance entering the system) contains about 2 percent
o f s o l u b l e o r g a n i c s , it is necessary to clean the stream for environmental
reasons. One technique for organics recovery i s w i t h a s u i t a b l e s o l v e n t
such as methyl ethyl ketone in a l i q u i d - l i q u i d m u l t i p l e - s t a g e e x t r a c t i o n
operation. T h e e x t r a c t o r l i g h t d e n s i t y p h a s e i s p r o c e s s e d i n a n e x t r a c t i o n
tower to recover the solvent overhead and the organic-rich material from
the bottom. The heavy density raffinate phase is processed in a raffinate
s t r i p p e r t o r e c o v e r t h a t p o r t i o n o f t h e s o l v e n t d i s s o l v i n g i n t h e w a t e r
phase. From the bottom of the raffinate stripper, t h e e f f l u e n t i s e s s e n t i a l l y
a water product of low biochemical oxygen demand (BOD). The organic product
- 7 -
Table 2. - - M a t e r i a l b a l a n c e , f e e d t o r e a c t o r - g a s i f i e r
Unit Pounds per ovendry Pounds per hour
ton of wood
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Wood waste
62.5 ODT/h
125,000 lb/h
1,500 ODT/D
Carbon 1,016 63,500
Hydrogen 126 7,880
Oxygen 796 49,740
Nitrogen 2 130
Ash 60 3,750
Moisture 2,000 125,000
4,000 250,000
A i r
Oxygen 750 46,875
Nitrogen 2,475 154,570
Water 55 3,455
3,280 204,900
Steam
Water
T o t a l I n
333 20,800
475,700
- 8 -
Table 3. --Material balance, products from reactor-gasifier
MW Mol/h Lb/h
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Crude gas1 /
Hydrogen 2 2,662 5,324
Carbon monoxide 28 3,325 98,100
Carbon dioxide 44 1,237 54,430
Methane 16 363 5,810
Hydrocarbon--Average 41 131 5,370
Nitrogen 28 5,525 154,700
Oxygen 32 69 2,206
Moisture 18 438 7,885
13,750 328,825
Ash
Condensate--water layer
Organic compounds
3,750
3,600
Water 139,525
143,125
Total Out 475,700
1/ Following partial condensation and separation of condensate.
- 9 -
from the extraction tower may be used as a fuel in the boiler. A l t e r -
n a t i v e l y , it may be economically feasible to separate the stream into its
components, m o s t l y a c e t i c a c i d , for byproduct value.
The cooled and partially purified gas is then compressed to about
100 lb/in.2g (fig. 1, step 3) and treated in a two-stage system to remove
carbon dioxide. I n t h e f i r s t s t a g e , a hot potassium carbonate system is
used to reduce CO2 content to about 300 parts per million (ppm) (fig. 1,
s t e p 4 ) . In the second stage, it is reduced to about 50 ppm using
monoethanolamine as a scrubbing agent (fig. 1, step 5). A single-stage
system of monoethanolamine could be used, b u t a t t h e e x p e n s e o f g r e a t l y
increased steam consumption.
The clean compressed gas passes to a cryogenic system (fig. 1, step 6).
In a series of switching exchangers, the residual CO2 and water vapor are
removed to prevent freezeup in the downstream e x c h a n g e r s a n d d i s t i l l a t i o n
towers. Next, methane and hydrocarbons are removed. C r y o g e n i c d i s t i l l a t i o n
is used to separate CO from nitrogen; t h e l i q u i d n i t r o g e n l e a v i n g t h e s y s t e m
is used to precool the incoming gas. The purified product gas is a mixture
of carbon monoxide and hydrogen. However, i t r e q u i r e s f u r t h e r p r o c e s s i n g
b e c a u s e i t i s n o t i n t h e r a t i o o f 2 : l o f H2 and CO required for syngas
to produce methanol.
SHIFT REACTION
Following cryogenic separation of the "inerts" the gas is compressed to
4 0 0 l b / i n .2g for shift conversion. A portion of the CO reacts with water
vapor in the presence of a n i r o n c a t a l y s t t o f o r m a d d i t i o n a l h y d r o g e n ( f i g . 1 ,
s t e p 8 ) , t o t h e e x t e n t t h a t t h e f i n a l g a s c o n t a i n s t h e r e q u i r e d 2 p a r t s
of hydrogen to 1 part of carbon monoxide. The following reaction takes
p l a c e i n t h e s h i f t r e a c t o r :
c a t a l y s t
CO + H2O H2 + CO2
Exothermic Reaction
590 Btu/lb CO
Because the shift reaction produces carbon dioxide, it is necessary to
utilize the hot potassium carbonate absorption system (fig. 1, step 9)
which removes about 97 percent of the carbon dioxide formed during the
s h i f t r e a c t i o n .
- 1 0 -
The synthesis gas is now compressed to a pressure ranging from 1,500 to
4 , 0 0 0 l b / i n . 2g and fed into the methanol synthesis reactor. I n t h e r e a c t o r ,
approximately 95 percent of the gas is converted to methanol, the balance
p a s s i n g a s i n e r t s t o t h e b o i l e r . T h e r e a c t i o n i s a s f o l l o w s :
c a t a l y s t
2H
2
+ CO CH
3
OH
Exothermic Reaction
1,200 Btu/lb CO
Two processes are available for synthesis of methanol, the Vulcan process
using a zinc-chrome catalyst operating at pressures ranging from about
2,000 to 4,000 lb/in.2 g and the more recent ICI copper catalyst process
2
operating at pressures ranging from 1,000 to 2,000 lb/in. g. A key factor
i n s e t t i n g t h e s y s t e m p r e s s u r e f o r e i t h e r p r o c e s s i s t h e p u r i t y o f t h e
feed. With increasing amounts of impurities, the system requires higher
pressure to minimize "inerts" leaving the system.
The crude methanol product from the synthesis reactor passes to a distillat
i o n t r a i n f o r s e p a r a t i o n o f t h e l i g h t e n d s a n d h i g h e r a l c o h o l s f r o m t h e
methanol product. The mixture of light ends and higher alcohols is used
a s a f u e l i n t h e b o i l e r . C a t a l y s t l i f e i s e x p e c t e d t o b e 6 y e a r s f o r m e t h a n o l
s y n t h e s i s a n d 2 t o 3 y e a r s f o r t h e s h i f t r e a c t o r .
PLANT SIZE
I n a c h e m i c a l p r o c e s s i n g f a c i l i t y , production cost depends mainly on capital
investment and raw material cost. The most common means for reducing unit
c o s t s i s t o b u i l d a h i g h - c a p a c i t y f a c i l i t y b e c a u s e i n v e s t m e n t f o r s c a l e u p
g e n e r a l l y i n c r e a s e s a s p r o d u c t i o n i n c r e a s e s b y a 0 . 6 f a c t o r . I n r e c e n t
y e a r s , t h e t r e n d i n t h e s y n t h e t i c m e t h a n o l i n d u s t r y h a s b e e n t o i n c r e a s e
plant sizes from about 50 million gpy to 200 million gpy. Twelve plants
in the U.S. can produce 1.2 billion gpy of methanol, as shown in table 4.
For the Forest Service engineering study, it was decided to size the methanol
from wood-waste plant at a capacity of 50 million gpy, comparable to the
small size plants making methanol from natural gas. The investment for
t h i s s i z e f a c i l i t y c a n b e s c a l e d u p i n a c c o r d a n c e w i t h s t a n d a r d p r o c e d u r e s
used by engineering organizations for chemical processing plants.
T h e F o r e s t S e r v i c e h a s e s t i m a t e d t h a t t h e c o s t o f c o l l e c t i n g a n d t r a n s p o r t i n g
wood waste to a central location for processing would range between $15
- 1 1 -
Table 4. --Methanol production
Capacity Number plants Total
(million gpy) (million gpy)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
22 1 22
50 3 150
80 1 80
100 4 400
160 1 160
200 1 200
230 1 230
Total U.S. capacity 1,242
Table 5.--Comparison of fuel values
Gross heating value Combustion Fuel value
e f f i c i e n c y
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Pct
Wood waste 18 million Btu/ODT
1 /66 $24.00/ODT
Coal 24 million Btu/ODT 80 $38.40/ODT
O i l 6 million Btu/bbl 85 $10.20/bbl
Natural gas 1 million Btu/mcf 87 $ 1.75/mcf
1/ Based on "as-is" or about 50 percent moisture by weight.
- 1 2 -
and $34/ODT. For comparison, the current delivered price for pulpwood
ranges between $40 and $60/ODT. Aside from its value as a potential source
of methanol, wood waste may be used as a source of fuel. Its minimum value
would thus seem to be its fuel value relative to more conventional fuels.
In the 1975 fuel market, wood waste can compete with other fuels when its
price is below $24/ODT, so that this would set the minimum cost for waste
wood utilized in a chemical process. A comparison of wood waste with convent
i o n a l f u e l s , assuming a value of $2/million Btu of net heat recovered
is shown in table 5.
ECONOMICS
An estimate of investment and operating costs for a 50 million gpy synthetic
methanol plant from wood waste has been developed. To determine the effect
of scaleup on cost, an estimate has also been prepared for a facility capable
of producing 200 million gpy. These estimates are compared with estimates
o f i n v e s t m e n t a n d o p e r a t i n g c o s t s f o r f a c i l i t i e s u s i n g n a t u r a l g a s a n d
coal as raw materials. A l l o f t h e s e i n v e s t m e n t s a r e b a s e d o n f a c i l i t i e s
u t i l i z i n g b o i l e r s t o p r o d u c e s t e a m t o g e n e r a t e e l e c t r i c i t y a n d t o d r i v e
turbines required for compression. Therefore, t h e s e p l a n t s a r e s e l f -
s u f f i c i e n t , requiring no outside utilities other than cooling water makeup.
Investment
The investment estimate requirement for a 50 million gpy methanol plant
using wood waste totals $64.0 million (1975 dollars). A breakdown of this
e s t i m a t e i n t o k e y s e c t i o n s i s g i v e n i n t a b l e 6 .
T h i s e s t i m a t e c o v e r s a c o m p l e t e " g r a s s r o o t s " f a c i l i t y , i n c l u d i n g o f f - s i t e
u t i l i t i e s , w o o d y a r d h a n d l i n g f a c i l i t i e s , f i n i s h e d p r o d u c t s t o r a g e , a n d
o f f i c e a n d l a b o r a t o r y b u i l d i n g s . It includes a contingency of 25 percent
and working capital of 5 percent. No provision has been made for expected
escalation in cost of equipment and construction labor.
Operating Costs
An estimate of operating costs for the 50 million gpy methanol plant is
l i s t e d i n t a b l e 7 . Production costs include fixed costs, raw material,
labor, and overhead. Fixed costs are based on an allowance of 8 percent
for depreciation, 4 percent for maintenance (including labor and material)
and 2 percent for local taxes and insurance. Profit is based on a nominal
return of 30 percent on investment, equal to 15 percent after Federal income
t a x .
- 1 3 -
T a b l e 6 . - -Investment estimate for wood waste methanol
plant of 50 million gpy.
D e s c r i p t i o n Investment
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Wood yard
G a s i f i e r
Cooling/scrubbing
Organic recovery
Primary compression
CO2 removal
Cryogenic
MeOH synthesis
O f f s i t e s
Steam generation
E l e c t r i c a l g e n e r a t i o n
Water treating
Cooling tower
Storage and shipping
F i r e p r o t e c t i o n
D i s t r i b u t i o n
Steam
Water
E l e c t r i c
B u i l d i n g s / s t r u c t u r e
Administration
Laboratory
Maintenance
Control house
Compressor building
U t i l i t y b u i l d i n g
Site development
Clearing, grading
Roadway, parking
Fencing
Railroad siding
S e w e r f a c i l i t i e s
Engineering and license
Estimate subtotal
Contingency--25 percent
$ 3,010,000
4,000,000
802,000
2,256,000
1,597,000
1,704,000
4,000,000
7,330,000
$7,200,000
1,587,000
840,000
1,727,000
1,152,000
250,000
12,756,000
$ 832,000
1,360,000
875,000
3,067,000
$ 362,000
106,000
348,000
104,000
105,000
300,000
1,370,000
$ 75,000
276,000
36,000
80,000
40,000
507,000
f e e $6,360,000
$48,759,000
12,191,000
$60,950,000
Working capital--5 percent 3,050,000
Total investment $64,000,000
- 1 4 -
Table 7 .--Production cost estimate and product price, wood
waste methanol plant of 50 million gpy
Annual
$ million
$ / G a l P e r c e n t
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Fixed costs
Depreciation 8 pct investment
Maintenance 4 pct investment
Taxes and insurance 2 pct investment
Raw material
Wood waste--1,500 T/D at $34/ODT 17.36 0.347 36.2
Labor
Operators--10 stations at $80,000/yr
Foremen-- 3 stations at $100,000/yr
Management--at $100,000/yr
$5.12
2.56
1.28
$ 8 . 9 6 $ 0 . 1 7 9 18.7
0.80
0.30
0.10
1.20 0.024 2.5
Overhead--100 pct labor 1.20 0.024 2.5
Profit--30 pct of investment before taxes 19.20 0.384 40.1
Total $47.92 $0.958 100.0
- 1 5 -
At a wood waste cost of $34/ODT, the selling price of methanol is estimated
a t $ 0 . 9 6 / g a l . At a wood waste cost of $15/ODT, the delivered price is
$ 0 . 7 7 / g a l . The 1975 price of methanol was $0.38/gal, Gulf Coast, tank
c a r l o t s .
Comparison With Natural Gas and Coal
Because of the simplicity of the conversion of natural gas to methanol,
the investment costs for such a plant is about one-third that of a comparable
wood waste facility. Also, conversion efficiency of natural gas to methanol
i s s i g n i f i c a n t l y g r e a t e r t h a n t h a t o f w o o d w a s t e . I t t a k e s 1 5 0 f t3 of
natural gas (containing more than 95 percent methane) or 4.9 lb to make
1 gallon of methanol. A comparison of efficiency of conversion of natural
gas, coal, and wood waste is shown in figure 2.
Conversion of coal to methanol, while considerably more efficient than
that of waste wood, involves more processing facilities because of the
greater amount of ash and sulfur (wood has no sulfur). Coal conversion
to syngas is more efficient because it has a higher carbon content and
less oxygen than wood. Comparison of investment requirements for a 50
and 200 million gpy methanol facility for each of these raw materials
is shown in figure 3.
The raw material input for three types of methanol synthesis plants is
shown in table 8.
I t i s o f i n t e r e s t t o n o t e t h a t t h e 5 0 m i l l i o n g p y f a c i l i t y u t i l i z i n g 1 5 0 0
ODT/D wood waste is comparable to a pulp mill producing about 800 T/D
o f f i n i s h e d p u l p . The 200 million gpy facility would be comparable to
3,300 T/D production of pulp.
Methanol selling price was calculated on a basis of 30 percent annual
profit on investment, 15 percent after Federal income tax. Production
c o s t s , g r o s s p r o f i t , a n d n e t p r o f i t f o r e a c h t y p e o f f a c i l i t y i s s h o w n
i n t a b l e 9 .
A comparison of the delivered price of methanol as a function of the raw
m a t e r i a l c o s t s a n d p l a n t s i z e f o r t h e s e t h r e e m e t h a n o l f a c i l i t i e s i s s h o w n
i n f i g u r e 4 .
- 1 6 -
Heating value: M 145 165
Natural gas--1,000 Btu/cubic foot
Coal, New Mexico coal with 19 percent ash
c o n t e n t - - 8,600 Btu/lb
Wood waste, Douglas-Fir with 25 percent bark
c o n t e n t - - 9,000 Btu/lb
E f f i c i e n c y :
Process efficiency--Heating value of methanol
as a percent of heating value of process feed.
Plant efficiency--Heat value of methanol as a
p e r c e n t o f t o t a l e n e r g y i n p u t i n t o p l a n t .
Figure 2. --Methanol Synthesis Conversion Efficiency for
Natural Gas, Coal, and Wood Waste
- 1 7 -
M 145 164 Investment Estimate
Based on 1975 costs
Includes 25% contingency
No escalation included
Figure 3.--Methanol Synthesis Plant Investment for Plants
o f 5 0 a n d 2 0 0 M i l l i o n G a l l o n s Y e a r F a c i l i t i e s ( A d d i -
tional cost for coal vs. wood due to pressurized system,
increased steam requirements, and desulfurization
equipment.)
- 1 8 -
Table 8. --Raw material input for methanol plants
50 million gpy 200 million gpy
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Natural gas 16.3 million cfd 65.2 million cfd
Coal 1,380 ODT/D 5,520 ODT/D
Wood waste 1,500 ODT/D 6,000 ODT/D
Table 9. --Methanol selling price
Cents per gallon
Production Gross Net S e l l i n g
c o s t p r o f i t p r o f i t p r i c e
50 million gpy
N a t u r a lg aast $ 1 . 7 5 / m c f 32.0 14.0 7.0 46.0
Coal at $38/ton 53.4 44.6 22.3 98.0
Wood waste at $34/ODT 59.6 38.4 19.2 98.0
200 million gpy
Natural gas at $1.75/mcf 25.8 9.2 4.6 35.0
C o a l a t $ 3 8 / t o n 41.4 26.6 13.3 78.0
Wood waste at $34/ODT 57.8 25.2 12.6 83.0
- 1 9 -
M 145 163
Production Costs P e r c e n t I n v e s t .
Depreciation 8
Maintenance 4
Taxes and insurance 2
P r o f i t b e f o r e t a x e s
A f t e r t a x e s
30
15
F i g u r e 4 . - -Methanol 1975 Selling Prices From Natural Gas, Coal, and
Wood Waste With Plant Capacities of 50 and 200 Million Gallons
Per Year.
U.S. GOVERNMENT PRINTING OFFICE: 1980-651-111157 - 2 0 - 4.5-21-6-77
CONCLUSIONS AND RECOMMENDATIONS
I t i s t e c h n i c a l l y f e a s i b l e b u t n o t e c o n o m i c a l l y a t t r a c t i v e t o p r o d u c e
methanol from wood waste. I f t h e u s e o f n a t u r a l g a s i s p r o h i b i t e d f o r
the production of methanol, a possible source for syngas would be
a d d i t i o n a l r e f i n e r y l i g h t - g a s s t r e a m s . I f t h i s l a t t e r s o u r c e i s i n s u f f i -
c i e n t , then coal would offer the most likely source of raw material,
particularly for a methanol plant located near or adjacent to a mining
operation.
In carrying out the Forest Service technical study on methanol-from-wood
waste, known technology was used. A key to improving the efficiency
o f t h e p r o c e s s l i e s i n i m p r o v i n g t h e e f f i c i e n c y o f t h e r e a c t o r - g a s i f i e r s
t o i n c r e a s e C O a n d H2 contents and thereby reduce CO2 and hydrocarbons.
The most promising reactor-gasifiers for wood gasification are the Moore-
Canada and the Union Carbide Purox unit. An experimental development
program is recommended for the Moore-Canada unit to attempt to improve
i t s e f f i c i e n c y . It is also recommended that experimental work be carried
out on the Purox unit using wood waste. P r e s s u r e p a r t i a l o x i d a t i o n s h o u l d
b e i n v e s t i g a t e d t o d e t e r m i n e i t s p r a c t i c a b i l i t y a n d e f f i c i e n c y .
A methanol-from-wood waste facility having a capacity of 50 million gpy
requires 1,500 ODT/D of wood waste. This is about the same quantity of
wood required for a kraft pulp mill producing 800 T/D of pulp. In view
o f t h e p u l p i n d u s t r y ' s p r o g r e s s i n u t i l i z i n g l o w e r a n d l o w e r g r a d e f e e d
materials such as sawdust and some bark, wood waste might be utilized
in the near future to produce pulp. Pulp would have a product value about
three times that of wood waste converted to methanol.
Upon examining methanol synthesis, o n e f i n d s t h a t t h e e n e r g y y i e l d s a r e
r e l a t i v e l y p o o r ; even in the case of natural gas and coal, the final methanol
product from natural gas contains about 60 percent of the total energy
i n p u t i n t o t h e p l a n t ( f i g u r e 2 ) . F o r a w o o d w a s t e f a c i l i t y , t h e y i e l d
is about 38 percent. T h a t i s , t h e t o t a l e n e r g y i n p u t f o r a 5 0 m i l l i o n
gpy methanol unit utilizing 1,500 ODT/D amounts to 1,125 million Btu/h
and the final methanol product has a heat value of 427 million Btu/h (gross
basis).

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