Chapter 16
Composition of Oils Obtained by Fast Pyrolysis of Different Woods Downloaded by COLUMBIA UNIV on July 18, 2012 | http://pubs.acs.org Publication Date: September 30, 1988 | doi: 10.1021/bk-1988-0376.ch016
J. Piskorz, D. S. Scott, and D. Radlein Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada Liquids obtained by fast pyrolysis of four different woods were analysed. On addition of excess water they separated into water-soluble and water-insoluble fractions. The former which is principally of carbohydrate origin was shown by HPLC analysis to consist of sugars, anhydrosugars and low molecular weight carbonyl compounds. The latter was shown by C NMR to be a "pyrolytic lignin". In this way 81% to 92% of the organic content of the liquids has been characterised. 13
During
the
biomass Waterloo 70%
of
last
has
Fast yet
liquids
reported
cess.
A fluidized
yields
are
0.5
or
gas
gms/hr,
Details
of
the
publications Several flash at
liquid the type
Roy e t
of
of
are
reactor.
pyrolysis
of
as
pyrolysis
of
process
or a
process
Waterloo gives
yields
of
which are
pyrolytic
conversion
reactor
range
of
one
and
450° of
with
throughput
of
p u b l i s h e d by
to
550°C
throughput
1
to
the
proabout
mm d i a m e -
a
4
to
liquid
at
1.5
up
the
optimum
about
for
(The
softwoods,
particles
use,
of
20
kg/hr.
authors
published describing
Most of
and were work
[5]
have
for
these
intended of
described
al.
to
under a
from biomass,
the
studies
in
[6]
several
of
from
carried
biomass
[4]
vacuum p y r o l y s i s on a
developed liquids
hearth
an upward the
high More
system
multiple from
the out
gas
reported
vacuum c o n d i t i o n s .
based
have
production
results were
promote
Roy and C h o r n e t
pyrolysis
Knight et
pyrolyzer
a
been
been
the
liquids
entrained
the in
fast
[3]. have
al.
This
with
with
from biomass
production
bed
University
used
in
biomass.
However,
yields
recently,
of
is
time
have
[2],
studies
the
non-catalytic
another
temperatures
production.
a bed
obtained
process
[1],
pyrolysis
higher
for
Two u n i t s and
fluidized at
Process).
residence
smaller.
100
a
from hardwoods
sand
normally
seconds
ter to
years
developed
Pyrolysis
organic
highest
six
been
flow
thermal
biomass.
0097-6156/88/0376-0167$06.00/0 « 1988 American Chemical Society
In Pyrolysis Oils from Biomass; Soltes, E., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
for
168
PYROLYSIS OILS FROM BIOMASS
However, few d e t a i l s o f t h e c h e m i c a l n a t u r e o f the p y r o l y t i c o i l s produced f r o m wood o r o t h e r biomass have been r e p o r t e d . Some recent s t u d i e s of the composition of p y r o l y s i s o i l s obtained from p o p l a r wood were c a r r i e d o u t by w o r k e r s of t h e P a c i f i c N o r t h w e s t L a b o r a t o r i e s o f B a t t e l l e I n s t i t u t e [7] and the Université de Sherbrooke [ 8 ] . Methods o f q u a n t i t a t i v e d e t e r m i n a t i o n o f f u n c t i o n a l groups i n t h e p y r o l y t i c o i l s from wood were t e s t e d i n our l a b o r a t o r y by N i c o l a i d e s [ 9 ] . However, more d e t a i l e d c h a r a c t e r i s a t i o n e x i s t s i n t h e l i t e r a t u r e f o r the p r o d u c t s of the t h e r m a l d e g r a d a t i o n o f c e l l u l o s e [10,11,12,13,14].
Downloaded by COLUMBIA UNIV on July 18, 2012 | http://pubs.acs.org Publication Date: September 30, 1988 | doi: 10.1021/bk-1988-0376.ch016
Results In p r e v i o u s l y r e p o r t e d t e s t s (3), y i e l d s have been c l a s s i f i e d as gases, o r g a n i c l i q u i d s , char and p r o d u c t water. Mass b a l a n c e s were g e n e r a l l y c l o s e t o 95% o r b e t t e r . E l e m e n t a l a n a l y s e s were a l s o r e p o r t e d f o r many runs, b u t i d e n t i f i c a t i o n of i n d i v i d u a l compounds was done o n l y f o r non-condensable gases and f o r some v o l a t i l e o r g a n i c s such as methanol, a c e t a l d e h y d e , f u r a n , e t c . However, more det a i l e d a n a l y s e s o f l i q u i d p r o d u c t s have r e c e n t l y been c a r r i e d o u t , and some of these p r e l i m i n a r y r e s u l t s w h i c h a r e o f p a r t i c u l a r s i g n i f i c a n c e a r e r e p o r t e d here. A l l e x p e r i m e n t a l r e s u l t s g i v e n were o b t a i n e d a t c o n d i t i o n s of c l o s e t o o p t i m a l f e e d r a t e , p a r t i c l e s i z e and r e s i d e n c e t i m e f o r maximum l i q u i d y i e l d a t t h e s t a t e d t e m p e r a t u r e s , as d e t e r m i n e d by over 200 bench s c a l e runs and 90 p i l o t s c a l e runs. These o p t i m a l c o n d i t i o n s a r e those shown i n Table I , t h a t i s , 480° t o 520°C, 0.5 t o 0.7 seconds apparent r e s i d e n c e t i m e and a maximum p a r t i c l e s i z e o f 1 mm. Table I shows the e x p e r i m e n t a l y i e l d s o f p r o d u c t s from s e l e c t e d runs f o r f o u r d i f f e r e n t woods whose p r o p e r t i e s a r e g i v e n i n T a b l e I I . High o r g a n i c l i q u i d y i e l d s a r e c h a r a c t e r i s t i c o f a l l f o u r mater i a l s when u n d e r g o i n g f a s t p y r o l y s i s i n our p r o c e s s . The t o t a l l i q u i d y i e l d , i n c l u d i n g w a t e r o f r e a c t i o n , v a r i e s from 70% t o 80% o f the d r y biomass f e d , a l l o f w h i c h can be d i r e c t l y used as a s u b s t i t u t e f u e l o i l i f d e s i r e d . The l i q u i d s a r e s i n g l e - p h a s e , homogeneous f l u i d s , w h i c h pour r e a d i l y , and w h i c h c o n t a i n from 15% t o 25% w a t e r depending on t h e f e e d m a t e r i a l and i t s m o i s t u r e c o n t e n t . These l i q u i d s a r e q u i t e s t a b l e a t room temperature. The w a t e r c o n t e n t , i n a p e r i o d o f t w e l v e months, was found t o i n c r e a s e s l i g h t l y p r e s u m a b l y due t o t h e s l o w p r o c e s s e s o f c o n d e n s a t i o n - p o l y m e r i z a t i o n g o i n g on even a t room temperature. A t h i g h e r t e m p e r a t u r e s , 120°C and above, the o i l s become i n c r e a s i n g l y u n s t a b l e and decompose w i t h e v o l u t i o n o f gas, and f i n a l l y c h a r i f i c a t i o n of a p o l y m e r i c r e s i d u e . A l l t h e p y r o l y s i s vapors produce an o i l m i s t f o l l o w i n g r a p i d quenchi n g , b u t t h e i r p o l a r c h a r a c t e r a l l o w s t h e easy u t i l i s a t i o n of e l e c t r o s t a t i c p r e c i p i t a t i o n i n the r e c o v e r y system o f a p y r o l y s i s p r o c e s s . P r e l i m i n a r y s m a l l s c a l e c o m b u s t i o n t e s t s c a r r i e d o u t w i t h the p y r o l y s i s o i l as produced (20% w a t e r c o n t e n t ) showed t h a t i t burns r e a d i l y i n a f u r n a c e w i t h a c o n v e n t i o n a l p r e s s u r e a t o m i z i n g burner, p r o v i d i n g the c o m b u s t i o n box i s preheated. I f an a i r a t o m i z i n g n o z z l e i s used w i t h a p i l o t f l a m e , no p r e - h e a t i n g o f t h e c o m b u s t i o n chamber i s n e c e s s a r y . L a r g e r s c a l e t e s t s f o r extended p e r i o d s have n o t y e t been done, b u t p r e l i m i n a r y work shows t h a t the p y r o l y s i s o i l has p o t e n t i a l as a s u b s t i t u t e f u e l o i l .
In Pyrolysis Oils from Biomass; Soltes, E., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
In Pyrolysis Oils from Biomass; Soltes, E., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 1988.
*
Z
2
3
6
Bench Scale Unit
Overall recovery wt%, m.f.
Total Gas
c
C H
4
2
C0 Cll
CO
H
Water Char Gas:
Yields, wt% of m.f. wood Organic l i q u i d
Apparent Residence Time, s Feed Rate, kg/hr
Moisture content, wt% P a r t i c l e Top Size, pin
Run » Temperature, °C
99.7
12.0
11.5
0.02 4.71 5.89 0.44 0.19 0.05 0.07 0.16
9.7 16.5
62.9
100.5
0.02 4.95 6.14 0.45 0.22 0.06 0.06 0.13
10.3 14.4
62.9
0.47 2.10
5.2 1000
««-
0.64 2.24
58 504
51 497
97.2
17.4 97.7
8.1 97.8
7.8
0.03
0.02 3.82 3.37 0.30 0.17 0.03 0.04
0.04 4.16 3.38 0.34 0.16 0.02
11.6 12.2
10.7 16.3
0.65 1.91
7.0 1000
43 500
66.5
0.70 2.07
«·
42 485
96.7
7.4
0.06
j
0.01 4.01 2.69 0.43 0.16 0.05 )
11.1 12.3
66.1
0.62 1.58
45 520
White Spruce
63.1
1
0.07 8.40 7.06 0.97 0.40 0.11 0.10 I 0.28 11
10.2 10.6
59.0
0.57 4.12
50 555
Brockville Poplar
95.7
12.1
0.04
101 .2
9.8
0.01 4.12 4.89 0.36 0.16 0.04 0.07 0.14
98.7
11.6
0.02 4.83 5.36 0.57 0.21 0.07 0.10 I 0.41 »
99.7
12.4
0.09
0.02 5.32 6.30 0.48 0.20 0.04
99*8
11.0
0.01 4.44 5.75 0.37 0.13 0.05 0.08 0.19
96.4
10.8
0.09 3.10
—
5.34 4.78 0.41 0.19
—
12.2 7.7
10.7 11.8 9.3 12.1 10.0 12.1
9.8 13.7
7.4 9.0 0.04 6.96 4.02 0.75 0.24
65.7
0.46 0.05
66.2
0.48 1.85
3.3 590
A-2* 497
65.8
0.55 2.24
4.6 1000
59 504
65.0
0.44 1.32
6.2 590
27 500
67.9
0.47 1.98
0.69 2.16
9.5 1000
81 515
IEA Poplar
67.3
5.9 590
63 508
Red Maple
3.8 590
14 532
Pyrolysis Yields from Different Woods
Table I
Downloaded by COLUMBIA UNIV on July 18, 2012 | http://pubs.acs.org Publication Date: September 30, 1988 | doi: 10.1021/bk-1988-0376.ch016
170
PYROLYSIS OILS FROM BIOMASS
o a m
ζ CO
Σ η ο ι ο ο ο
νο
Ό ι to
Ο
C Ό Π3 4-> 03 C Γ —
Ό-
Ό-
Ό-
Ο
ο
Ό" Ό*
Ό·
C
Ο Ο
Γ —
Ο
Downloaded by COLUMBIA UNIV on July 18, 2012 | http://pubs.acs.org Publication Date: September 30, 1988 | doi: 10.1021/bk-1988-0376.ch016
ο
in CM I 00 CO
CL
ω
ο
Ό-
•
ο
CO
α» (Ό
L.
ω «j
4->
•Μ
Η Η
-α Φ
ω
r— -Q
Lu
to
ί
ο Ο
ω
ο 3
£_
CL
00 0) 4-> •rJC
ω •r—
c (Ό Ό 4-3 Ο
CL ·Γ-
c α> c_
ίο υ « Ο
ω
vo ο
ι— Χ c u e
α»
I/)
Ό-
m
σ>
Ό-
co C\J vo
ΟΟ
vo CO
ο ι—I
Ό-
Η
U I O U
Ο
