Catalytic fast pyrolysis of wood and alcohol mixtures in a fluidized bed reactor

Article abstract of DOI:10.1039/c1gc15619e

Catalytic fast pyrolysis (CFP) of pine wood, alcohols (methanol, 1-propanol, 1-butanol and 2-butanol) and their mixtures with ZSM-5 catalyst were conducted in a bubbling fluidized bed reactor. The effects of temperature and weight hourly space velocity (WHSV) on the product carbon yields and selectivities of CFP of pure pine wood and methanol were investigated. A maximum carbon yield of petrochemicals (aromatics + C₂-C₄ olefins + C₅ compounds) from pine wood of 23.7% was obtained at a temperature of 600 °C and WHSV of 0.35 h^-1. A maximum petrochemical yield from methanol of 80.7% was obtained at a temperature of 400 °C and WHSV of 0.35 h^-1. Thus, the optimal conditions for conversion of pine wood and methanol are different. The CFP of pine wood and methanol mixtures was conducted at 450 °C and 500 °C. The hydrogen to carbon effective (H/C_eff) ratio of the feed was adjusted by changing the relative amount of methanol and wood. The petrochemical yield was a function of the H/C_eff ratio and more petrochemicals are produced from biomass when methanol is added to the CFP process. Co-feeding of ¹²C pine wood and ¹³C methanol was carried out at 450 °C. The isotopic study showed that all the hydrocarbon products contained mixtures of ¹²C and ¹³C, indicating that the carbon is mixed within the zeolite. However, the distribution of carbon was skewed depending on the product. The toluene, xylene, propylene and butenes contained more ¹³C. The naphthalene and ethylene contain more ¹²C. Wood was also co-processed with 1-propanol, 1-butanol, and 2-butanol, which showed a similar effect as methanol with an increasing petrochemical yield with an increasing H/C_eff ratio of the feed. This paper demonstrates that CFP can selectively produce a mixture of compounds where the overall yield is a function of the H/C_eff ratio of the feed.

Full text of DOI:10.1039/c1gc15619e

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COVER ARTICLE
Huber et al.
Catalytic fast pyrolysis of wood and alcohol mixtures
in a fluidized bed reactor

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PAPER
Catalytic fast pyrolysis of wood and alcohol mixtures in a fluidized bed
reactor
Huiyan Zhang,a,b Torren R. Carlson,b Rui Xiaoa and George W. Huber*b
Received 27th May 2011, Accepted 19th August 2011
DOI: 10.1039/c1gc15619e
Catalytic fast pyrolysis (CFP) of pine wood, alcohols (methanol, 1-propanol, 1-butanol and
2-butanol) and their mixtures with ZSM-5 catalyst were conducted in a bubbling fluidized bed
reactor. The effects of temperature and weight hourly space velocity (WHSV) on the product
carbon yields and selectivities of CFP of pure pine wood and methanol were investigated. A
maximum carbon yield of petrochemicals (aromatics + C2–C4 olefins + C5 compounds) from pine
wood of 23.7% was obtained at a temperature of 600 ◦C and WHSV of 0.35 h-1. A maximum
petrochemical yield from methanol of 80.7% was obtained at a temperature of 400 ◦C and WHSV
of 0.35 h-1. Thus, the optimal conditions for conversion of pine wood and methanol are different.
The CFP of pine wood and methanol mixtures was conducted at 450 ◦C and 500 ◦C. The
hydrogen to carbon effective (H/Ceff) ratio of the feed was adjusted by changing the relative
amount of methanol and wood. The petrochemical yield was a function of the H/Ceff ratio and
more petrochemicals are produced from biomass when methanol is ad◦ded to the CFP process.
Co-feeding of 12C pine wood and 13C methanol was carried out at 450 C. The isotopic study
showed that all the hydrocarbon products contained mixtures of 12C and 13C, indicating that the
carbon is mixed within the zeolite. However, the distribution of carbon was skewed depending on
the product. The toluene, xylene, propylene and butenes contained more 13C. The naphthalene
and ethylene contain more 12C. Wood was also co-processed with 1-propanol, 1-butanol, and
2-butanol, which showed a similar effect as methanol with an increasing petrochemical yield with
an increasing H/Ceff ratio of the feed. This paper demonstrates that CFP can selectively produce a
mixture of compounds where the overall yield is a function of the H/Ceff ratio of the feed.
thus greatly increase the cost of biomass processing. Catalytic
1. Introduction
fast pyrolysis (CFP) is a new promising technology to directly
Environmental issues caused by using fossil fuels, the growing
convert solid biomass into hydrocarbon products that fit directly
energy demand and the depletion of petroleum resources have
into the current infrastructure.47–55 CFP is a single step process
stimulated the development of new sources for the production
that uses inexpensive zeolite catalysts. Furthermore, the reactor
of renewable liquid fuels.1,2 Due to its low cost and abundant
is operated at atmospheric pressure and does not require the
availability, lignocellulosic biomass has been studied world wide
use of hydrogen. One of the critical factors that will influence
to produce liquid fuels and chemicals.3–59 There are several routes
the future prospects of biofuels is product flexibility.56 CFP of
for converting solid biomass or its derivatives to liquid fuels
biomass can produce five of the six primary petrochemicals,
and chemicals, such as aqueous-phase reformation,18–24 pyrol-
including benzene, toluene, xylene, ethylene and propylene.48
ysis followed by vapors upgrading,25–29 gasification followed
One of the critical challenges with CFP is to increase the yield
by Fischer–Tropsch synthesis to produce liquid alkanes,30–32
of usable petrochemicals.
hydrodeoxygenation of pyrolysis oil,33–35 and the conversion of
A parameter called the hydrogen to carbon effective (H/Ceff)
pyrolysis oil or its derivatives to aromatic hydrocarbons over
ratio (also called the effective hydrogen index) can be used to
zeolite catalysts.36–46 All of these routes involve multiple steps and
compare the relative amount of hydrogen present in different
feeds.57 The H/Ceff ratio is defined in eqn (1), where H, C and O
are the mol of hydrogen, carbon and oxygen, respectively.
aSchool of Energy and Environment, Southeast University, Nanjing,
210096, PR China
bDepartment of Chemical Engineering, University of
Massachusetts-Amherst, Amherst, MA 01002, USA.
E-mail: huber@ecs.umass.edu; Tel: +4135450276
H −2O
(1)
H/Ceff
=
C
98 | Green Chem., 2012, 14, 98–110
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The Royal Society of Chemistry 2012
©

Fig. 1 Overall reaction chemistry for the co-catalytic fast pyrolysis of cellulose and methanol. Adapted from Carlson et al.48
Chen et al.57 showed that feedstocks with an H/Ceff ratio less
than 1 are difficult to upgrade to premium products over a ZSM-
5 catalyst due to rapid deactivation of the catalyst. The H/Ceff
ratio of petroleum-derived feeds ranges from 1 (for benzene)
to slightly over 2 (for liquid alkanes), whereas that of biomass
is only from 0 to 0.3. Thus, biomass is a hydrogen-deficient
molecule. We have recently shown that the yield of usable
petrochemical products from zeolite conversion of different
biomass-derived feedstocks is a function of the H/Ceff ratio
of the feedstock.58,59 This suggests that the petrochemical yield
from CFP of biomass could be increased by co-feeding in an
additional feedstock that has a high H/Ceff ratio. Methanol has
an H/Ceff ratio of 2 and has been shown to give high yields of
hydrocarbon products when processed over a zeolite catalyst.60–62
Therefore, methanol could potentially be co-fed with biomass to
increase the overall H/Ceff ratio of the feed. Methanol is a liquid
at room temperature and easier to transport than hydrogen,
which is a gas at room temperature.
polymerization of the furans and oxygenated pyrolysis vapors.
The aromatic formation reaction proceeds through a com-
mon intermediate or “hydrocarbon pool” within the zeolite
framework.68–75 Co-feeding methanol with biomass may alter
the “hydrocarbon pool” and increase the rate of aromatic
production.
We know of three papers in the literature that have pre-
viously reported on co-feeding of biomass or its derivatives
with methanol over HZSM-5 catalysts.40,76,77 These studies all
reported increased aromatic and olefin yields when methanol
is co-fed with the biomass or its derivatives. Gayubo et al.40,76
conducted co-feeding of bio-oil and methanol in a fluidized bed
and conical spouted bed reactor with HZSM-5 and Ni/HZSM-
5 catalysts. They reported that co-feeding of methanol with the
pyrolysis oil increased the C2–C4 olefin yield and decreased the
CO, CO2, and coke yields. Evans and Milne77 co-fed methanol
with wood in a quartz microreactor with HZSM-5 catalyst. They
showed that more aromatic products were formed with the co-
feeding process.
The reaction pathways for co-catalytic fast pyrolysis (co-
CFP) of cellulose (a biomass model compound) and methanol
are shown in Fig. 1. The CFP of cellulose involves both
homogeneous and heterogeneous reactions. The first step is the
homogeneous thermal decomposition of cellulose to a liquid
intermediate that is then converted into anhydrosugars.63–65
The anhydrosugars are relatively thermally stable and do not
form large amounts of coke in the gas phase.66 However, the
anhydrosugars can undergo dehydration and re-arrangement
reactions to form intermediate oxygenates, such as furans and
smaller aldehydes. These reactions can happen in either the
gas phase or in the presence of a catalyst.67 In the second
step, these intermediate oxygenates then diffuse into the zeolite
catalyst pores and form monocyclic aromatics, C2–C4 olefins
and C5 compounds through a series of dehydration, decar-
bonylation, decarboxylation and oligomerization reactions. The
aromatic formation rate is relatively slow compared to the
pyrolysis reactions.67 The major competing reaction with the
formation of aromatics is the formation of coke from the
The objective of this work is to study the CFP of pine wood
and methanol mixtures in a fluidized bed reactor to see if the
overall petrochemical yield can be improved by the addition of
alcohol feeds. The effect of temperature and weight hourly space
velocity (WHSV) on the product carbon yields and selectivities
of CFP of pine wood and methanol are studied to determine a
suitable operation condition for co-CFP of these feed mixtures.
We compare the economic potential of CFP of pine wood
and methanol mixtures to assess the potential benefits of co-
feeding. Isotopically labelled 13C methanol was processed with
pine wood to identify how methanol and wood are incorporated
into the final products. We also study the co-CFP of pine
wood with other alcohols, such as 1-propanol, 1-butanol and
2-butanol to determine if these feeds can be used to enhance the
petrochemical yield. This paper thus provides critical insights
as to how the yield of petrochemicals can be increased by co-
feeding of pine wood with feeds that have a high H/Ceff ratio
like alcohols.
This journal is
The Royal Society of Chemistry 2012
Green Chem., 2012, 14, 98–110 | 99
©

solid particles. Following the cyclone, the vapours flow into a
condenser train. The first three condensers are operated at 0 ◦C
in an ice bath and the following four condensers are operated at
-55 ◦C in a dry ice/acetone bath. The non-condensable vapours
exiting the condenser train are collected by a gas sampling bag
and analyzed by GC/FID and GC/TCD. A carrier gas flow rate
of 1400 mL min-1 was used for all experiments, as measured by
a bubble flow meter. We used GC/FID to analyze the amount
of gas products produced. Ethanol was added to the condensers
to help condense the condensable products. All liquid products
were soluble in the ethanol. These liquid products were then
analyzed by GC-FID. For the isotopically labelled feed run, the
gas samples and liquids were further analyzed by GC/MS. For
a typical run, pine wood is fed to the reactor for 30 min. At
the end of the run, the reactor is purged with 1200 mL min-1 for
another 30 min to strip any remaining product from the catalyst.
2. Experimental section
2.1 Materials
2.1.1 Feeds. 12C methanol, 1-propanol, 1-butanol and 2-
butanol were purchased from Sigma-Aldrich and used as
feedstocks without any pretreatment. 13C methanol (Product ID:
CLM-359-5) with 99 atom% 13C was bought from Cambridge
Isotope Laboratories, Inc. The wood used in this study is eastern
pine wood sawdust sourced from a local sawmill. Prior to the
experiments, the wood was ground with a high-speed rotary
cutting mill and then sieved to yield a particle size of 18–120
mesh (120–880 micron). The elemental composition of the wood
is 46.2 wt% carbon, 6.0 wt% hydrogen and 47.3 wt% oxygen (by
difference). The proximate analysis result is 4.0 wt% moisture,
74.2 wt% volatile, 21.3 wt% fixed carbon and 0.5 wt% ash. On
the dry basis the approximate molecular formula of the wood is
therefore C3.8H5.8O2.7.
◦
After reaction, the catalyst is regenerated at 600 C in 800 mL
min-1 flowing air. The effluent gas during regeneration mainly
contains CO2, CO and H2O, which was passed in series through
a copper catalyst, a dryrite trap and an ascarite trap. The copper
catalyst is a copper oxide powder (13% CuO on alumina, Sigma-
Aldrich) and is operated at 250 ◦C to convert CO to CO2. The
coke carbon yield is determined by the mass of CO2 captured by
the ascarite trap.
2.1.2 Catalyst. The catalyst used in this work is a commer-
cial spray dried 40% ZSM-5 catalyst (Intercat. Inc.). The particle
size of the catalyst is from 150 to 230 mesh (62–106 micron). For
a typical run, 30 g catalyst is loaded in the reactor. Prior to
reactions, the ◦catalyst was calcined in the fluidized bed reactor
for 5 h at 600 C in 800 mL min-1 flowing air.
2.2 Experimental setup
3. Results
CFP and co-CFP of pine wood and alcohols were conducted
in a fluidized bed reactor system, as shown in Fig. 2, which
can be found elsewhere.48 The fluidized bed reactor is a 2 inch
ID 316 stainless steel tube with a freeboard height of 10 inch.
The catalyst bed is supported by a distributor plate made from
stacked 316 stainless steel mesh (300 mesh). The pine wood is fed
into the side of the reactor (1 inch above the distributor plate)
by a stainless steel auger from a sealed feed hopper. The hopper
is swept with helium at a rate of 200 mL min-1 to maintain an
inert environment in the feeding unit. Methanol is fed into the
fluidizing gas stream at the inlet of the plenum by a syringe
pump. The methanol vaporizes in the gas stream and enters
the reactor through the distributor plate as vapours. Ultra high
purity helium (99.99%) was used as the fluidizing gas. The gas
flow rate was set as 1200 mL min-1 and controlled by a mass
flow controller. Both the reactor and the inlet gas stream are
heated to reaction temperature before reaction. A cyclone is
located at the exit of the reactor to remove and collect entrained
3.1 Catalytic fast pyrolysis of pine wood
3.1.1 Effect of reaction temperature on pyrolysis product
yields and selectivities. Fig. 3 and Table 1 show the product
carbon yields for CFP of pine wood in the fluidized bed reactor
at different temperatures. As can be seen from the figure, the
aromatic and olefin yields go through a maximum of 13.9% and
◦
9.4% at 600 C, respectively. The maximum total carbon yield
of petrochemicals (aromatics + C2–C4 olefins + C5 compounds)
is 23.7%, which occurs at 600 ◦C. The coke and unidentified
oxygenates yields decrease with increasing temperature from
40.4% and 28.4% at 400 ◦C to 19.7% and 2.9% at 650 ◦C,
respectively. The CO and methane yields increase with increasing
temperature from 16.2% and 0.3% at 400 ◦C to 44.1% and
6.9% at 650 ◦C, respectively. The detailed product carbon
yields and selectivities are listed in Table 1. The main aromatic
products include benzene, toluene, xylene and naphthalene.
Benzene and naphthalene selectivities increase, while xylene and
Fig. 3 Product yields as a function of temperature for CFP of pine
wood. Reaction conditions: ZSM-5 catalyst, 0.35 h-1 WHSV. 1200 mL
min-1 helium fluidizing flow rate, 30 min reaction time. Key: (a) ꢀ
Fig. 2 The schematic of the fluidized bed reactor system for catalytic
fast pyrolysis of biomass and alcohols.
Aromatics, ᭡ C –C olefins,
C compounds, ᭜ Unidentified; (b) ꢁ
᭹
2
4
5
Methane, ꢀ CO2, CO, ᭛ Coke.
᭺
100 | Green Chem., 2012, 14, 98–110
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The Royal Society of Chemistry 2012
©

Table 1 Detailed product yields and selectivities for CFP of pine wood
at various temperatures and WHSV = 0.35 h-1. Aromatic selectivity is
defined as the moles of carbon in the product divided by the total moles
aromatic carbon. Olefin selectivity is defined as the moles of carbon in
the product divided by the total moles olefin carbon
Table 2 Detailed product yields and selectivities for CFP of pine wood
at various WHSV values and 600 ◦C. Aromatic selectivity is defined as
the moles of carbon in the product divided by the total moles aromatic
carbon. Olefin selectivity is defined as the moles of carbon in the product
divided by the total moles olefin carbon
T/◦C
WHSV (h-1)
Compound
400
450
500
600
650
Compound
0.11
0.18
0.35
0.60
0.97
1.98
Overall yields
Aromatics
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
CO2
CO
Coke
Total balance
Unidentified
Aromatic selectivity
Benzene
Overall yields
Aromatics
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
CO2
CO
Coke
Total balance
Unidentified
Aromatic selectivity
Benzene
4.6
2.7
0.3
7.6
0.3
5.9
4.3
0.5
10.7
0.6
8.9
19.7
41.6
81.4
18.6
10.5
5.4
0.3
16.2
2.1
7.7
25.6
31.7
83.3
16.7
13.9
9.4
0.5
23.7
4.3
9.5
32.2
26.7
96.4
3.6
7.8
6.8
0.3
14.9
6.9
11.6
44.1
19.7
97.1
2.9
6.7
7.6
0.7
15.0
3.0
18.2
28.3
32.9
97.4
2.6
10.4
8.6
0.8
19.8
2.9
14.3
29.2
30.6
96.8
3.2
13.9
9.4
0.5
23.7
4.3
9.5
32.2
26.7
96.4
3.6
11.4
7.8
0.3
19.5
5.9
8.2
36.3
23.6
93.4
6.6
9.8
7.0
0.4
17.2
5.3
7.7
32.0
23.5
85.7
14.3
4.4
7.7
0.1
12.3
6.5
8.4
30.8
24.8
82.7
17.3
7.1
16.2
40.4
71.7
28.4
13.4
30.9
4.9
10.8
32.2
3.4
15.3
34.7
4.5
20.8
37.1
2.3
38.8
30.7
0
25.4
40.1
1.7
21.7
37.2
1.8
20.8
37.1
2.3
24.3
32.0
2.0
29.2
24.8
2.6
36.4
20.9
2.0
Toluene
Toluene
Ethyl-benzene
p-Xylene and
m-Xylene
o-Xylene
Styrene
Benzofuran
Indene
Ethyl-benzene
p-Xylene and
m-Xylene
o-Xylene
Styrene
Benzofuran
Indene
29.6
33.2
24.1
16.6
8.9
18.1
19.0
16.6
14.2
13. 5
9.0
7.1
0
3.0
2.4
1.4
7.3
4.8
0
4.3
2.6
1.1
7.7
3.5
3.7
1.6
3.3
1.5
7.7
3.2
2.8
1.9
2.6
1.4
2.2
0
0
1.8
1.3
16.4
3.8
0
0.3
1.4
0.6
8.7
1.1
3.8
1.6
2.3
1.0
3.2
2.8
1.9
2.6
1.4
4.2
2.0
2.2
3.5
1.7
2.8
2.7
2.8
2.6
1.4
2.8
1.6
2.9
2.3
1.0
Phenol
Phenol
Naphthalene
Olefin selectivity
Ethylene
Propylene
Butenes
11.2
Naphthalene
Olefin selectivity
Ethylene
Propylene
Butenes
10.6
11.2
13.9
17.7
21.3
36.5
48.1
7.2
54.9
36.0
7.2
49.0
37.8
7.0
52.8
36.0
6.0
66.4
26.4
3.8
55.6
24.9
14.2
5.2
49.3
32.3
12.3
6.0
52.8
36.0
6.0
61.1
29.5
4.6
53.3
37.0
4.8
49.4
40.1
5.9
Butadiene
8.2
1.9
6.2
5.2
3.4
Butadiene
5.2
4.9
4.9
4.6
ethyl benzene selectivities decrease with increasing temperature.
The main C2–C4 olefins produced in the reactions include
ethylene, propylene, butenes and butadiene. Propylene and
butenes selectivities decrease and ethylene selectivity increases
with increasing temperature.
3.1.2 Effect of weight hourly space velocity on pyrolysis
product yields and selectivities. The product carbon yields for
CFP of pine wood at 600 ◦C as a function of weight hourly
space velocity (WHSV) are shown in Fig. 4 and Table 2. WHSV
is defined as the mass flow rate of feed divided by the mass of
catalyst in the reactor. A WHSV of 0.11–1.98 h-1 was used for
these experiments, which corresponds to feeding between 1.65–
29.7 g of wood to the reactor. The aromatic and olefin yields
go through a maximum at WHSV = 0.35 h-1. The unidentified
oxygenates yield increases from 2.6% at WHSV = 0.11 h-1 to
17.3% at WHSV = 1.98 h-1 with increasing WHSV. The methane
yield increases from 3.0% to 6.5% with increasing WHSV. The
CO yield goes through a maximum of 36.3% at WHSV = 0.60 h-1.
The CO2 and coke yields decrease with increasing WHSV. The
xylene and toluene selectivities decrease, whereas the benzene
and naphthalene selectivities increase with increasing WHSV.
The ethylene and butenes selectivities decrease with the increase
of WHSV.
Fig. 4 Product yields as a function of WHSV for CFP of pine wood.
◦
Reaction conditions: ZSM-5 catalyst, 600 C. 1200 mL min-1 helium
fluidizing flow rate, 30 min reaction time. Key: (a) ꢀ Aromatics, ᭡ C2–
C olefins, C compounds, ᭜ Unidentified; (b) ꢁ Methane, ꢀ CO ,
᭹
4
5
2
CO, ᭛ Coke.
᭺
methanol at different temperatures with WHSV of 0.35 h-1 are
shown in Fig. 5 and Table 3. Temperature has a pronounced
effect on the product distribution. The yields of C2–C4 olefins,
aromatics, C5 compounds and unidentified oxygenates decrease
with increasing temperature. The yields of methane, CO2, CO
and coke increase with increasing temperature. Temperature
has the biggest effect on the olefin and CO yields. The olefin
yield decreases from 52.3% at 400 ◦C to 0.2% at 600 ◦C. The
CO yield increases from 1.3% at 400 ◦C to 59.7% at 600 ◦C.
The petrochemical yield decreases from 80.7% at 400 ◦C to
3.8% at 600 ◦C. Table 3 lists the detailed product yields and
selectivities. The benzene and toluene selectivities increase and
xylene selectivity decreases with the increase of temperature. At
3.2 Catalytic conversion of methanol
3.2.1 Effect of reaction temperature on product yields and
selectivities. Product carbon yields of catalytic conversion of
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The Royal Society of Chemistry 2012
Green Chem., 2012, 14, 98–110 | 101
©

Table 3 Detailed product yields and selectivities for catalytic con-
version of methanol at various temperatures and WHSV = 0.35 h-1.
Aromatic selectivity is defined as the moles of carbon in the product
divided by the total moles aromatic carbon. Olefin selectivity is defined
as the moles of carbon in the product divided by the total moles olefin
carbon
Table 4 Detailed product yields and selectivities for catalytic con-
version of methanol at various WHSV values and 450 ◦C. Aromatic
selectivity is defined as the moles of carbon in the product divided by the
total moles aromatic carbon. Olefin selectivity is defined as the moles of
carbon in the product divided by the total moles olefin carbon
WHSV (h-1)
T/◦C
Compound
0.08
0.15
0.35
0.68
2.11
Compound
400
450
500
600
Overall yields
Aromatics
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
CO2
CO
Coke
Total balance
Unidentified
Aromatic selectivity
Benzene
Overall yields
Aromatics
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
CO2
CO
Coke
Total balance
Unidentified
Aromatic selectivity
Benzene
2.8
14.2
2.6
19.5
9.9
27.8
36.0
6.4
99.7
0.3
9.7
45.2
4.8
59.7
10.5
12.0
8.1
5.7
95.9
4.1
11.1
52.6
7.9
71.5
4.5
8.9
5.1
2.1
92.1
7.9
14.0
50.8
12.7
77.5
3.6
7.0
1.8
1.1
90.9
9.1
13.5
51.2
14.2
78.9
2.2
3.0
0.9
0.3
85.3
14.7
14.8
52.3
13.6
80.7
1.8
3.7
1.3
1.8
89.3
10.7
11.1
52.6
7.9
71.5
4.5
8.9
5.1
2.1
92.1
7.9
5.5
34.6
1.8
41.9
11.0
21.5
21.0
2.9
3.5
0.2
0.1
3.8
8.4
21.1
59.7
5.5
98.4
1.6
98.3
1.7
9.2
22.1
0
3.8
16.5
1.3
3.3
15.6
1.6
2.9
17.7
2.2
2.2
16.0
2.6
1.8
11.1
1.8
3.3
15.6
1.6
9.6
19.3
2.5
23.7
40.6
2.0
Toluene
Toluene
Ethyl-benzene
p-Xylene and
m-Xylene
o-Xylene
Indene
Olefin selectivity
Ethylene
Propylene
Butenes
Butadiene
Ethyl-benzene
p-Xylene and
m-Xylene
o-Xylene
Indene
Olefin selectivity
Ethylene
Propylene
Butenes
Butadiene
49.5
54.9
56.5
55.7
58.8
57.3
56.5
43.3
20.8
13.1
6.2
10.2
13.2
9.5
13.6
9.8
11.6
9.2
11.3
9.5
18.5
9.5
13.6
7.6
11.0
1.2
2.6
35.0
34.1
27.7
3.2
17.3
52.7
25.3
4.7
18.0
50.2
25.9
5.9
14.9
42.6
37.4
5.1
12.6
42.3
43.2
1.9
14.3
43.7
38.3
3.7
18.0
50.2
25.9
5.9
20.2
51.5
24.9
3.4
0
100
0
0
Fig. 6 Product yields as a function of WHSV for catalytic conversion of
methanol. Reaction conditions: ZSM-5 catalyst, 450 ◦C. 1200 mL min-1
helium fluidizing flow rate, 30 min reaction time. Key: (a) ꢀ Aromatics,
Fig. 5 Product yields as a function of temperature for catalytic
conversion of methanol. Reaction conditions: ZSM-5 catalyst, 0.35 h-1
WHSV. 1200 mL min-1 helium fluidizing flow rate, 30 min reaction
᭡ C –C olefins, C compounds, ᭜ Unidentified; (b) ꢁ Methane, ꢀ
᭹
2
4
5
time. Key: (a) ꢀ Aromatics, ᭡ C2–C4 Olefins,
C5 compounds, ᭜
Unidentified; (b) ꢁ Methane, ꢀ CO2, CO, ᭛ Coke.
᭹
CO2, CO, ᭛ Coke.
᭺
᭺
high temperature (600 ◦C) almost all the methanol is converted
into CO, CO2, methane and coke.
WHSV. These experiments show that the maximum petrochem-
ical yield for methanol conversion occurs at low temperatures
and high WHSV.
3.2.2 Effect of weight hourly space velocity on product yields
and selectivities. Fig. 6 and Table 4 show product yields as
a function of WHSV for catalytic conversion of methanol at
450 ◦C. The petrochemical yields increase rapidly at lower
WHSV, while CO, CO2, methane and coke yields show the
opposite trend. At WHSV above 0.50, little change is observed.
The petrochemical yield increases from 19.5% to 59.7% when the
WHSV increases from 0.08 h-1 to 0.15 h-1. The petrochemical
yield increases to 71.5% at WHSV = 0.35 h-1, however, further
increasing the WHSV has little effect on the total yield. This
indicates that methanol conversion is sensitive at low WHSV.
Benzene selectivity decreases, and xylene selectivity increases
with increasing WHSV. Ethylene selectivity decreases, and
propylene and butenes selectivities increase with the increase of
3.3 Co-catalytic fast pyrolysis of pine wood and methanol
3.3.1 Effect of hydrogen to carbon effective (H/Ceff) ratio at
450 ◦C. CFP of pine wood and methanol mixtures was carried
out by co-feeding them to the reactor. The H/Ceff ratio of the
feed was adjusted by changing the space velocity ratio of pine
wood and methanol. Based on our previous methanol and wood
◦
◦
runs, we decided to operate the reactor at 450 C and 500 C.
The product yields of co-CFP of pine wood and methanol at
450 ◦C as a function of H/Ceff ratio is shown in Fig. 7 and Table
5. The petrochemical yield increases non-linearly with increasing
H/Ceff ratio. This curvature indicates that there is a synergistic
effect between the feeds since pure addition of the yields would
102 | Green Chem., 2012, 14, 98–110
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The Royal Society of Chemistry 2012
©

Table 5 Detailed product yields and selectivities for co-CFP of pine
wood and methanol at various H/Ceff ratios and 450 ◦C. Aromatic
selectivity is defined as the moles of carbon in the product divided by the
total moles aromatic carbon. Olefin selectivity is defined as the moles of
carbon in the product divided by the total moles olefin carbon
7.9% at H/Ceff = 2. As shown in Fig. 7(b), the yields of CO
and coke decrease significantly with the increase of the H/Ceff
ratio as non-linear curves, while that of CO2 remains constant.
Fig. 8 shows the selectivities of benzene, toluene, xylene and
naphthalene in the aromatic products and ethylene, propylene,
butenes and butadiene in olefin products. As shown in the figure,
the selectivities of the more valuable chemicals, such as xylene,
propylene, butenes and butadiene, increase significantly with the
increase of H/Ceff ratio, while the selectivities of the less valuable
chemicals, such as naphthalene decreases.
H/Ceff (mol/mol) ratio
Compound
0.11 0.47 0.76 1.05 1.25 1.64 2.00
Pine wood WHSV
(h-1)
0.35 0.46 0.23 0.28 0.20 0.06
0.13 0.15 0.35 0.37 0.34
0
Methanol WHSV
0
0.35
0.35
(h-1)
Total WHSV (h-1)
Overall yields
Aromatics
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
0.35 0.59 0.38 0.63 0.56 0.41
5.9 14.8 18.8 21.4 21.1 14.0
4.3 13.5 18.7 26.4 32.9 47.9
11.1
52.6
7.9
71.5
4.5
8.9
0.5
1.2
2.9
3.7
4.7
6.3
10.7 29.4 40.5 51.4 58.7 68.3
0.6
8.9
1.4
7.3
2.6
6.8
1.5
7.1
9.4
2.1
7.2
7.7
3.1
7.8
5.8
7.4
CO2
CO
Coke
19.7 14.9 12.6
41.6 30.3 23.4 17.8 14.5
5.1
2.1
Total balance
Unidentified
Theoretical
petrochemical yield
Aromatic selectivity
Benzene
81.4 83.3 85.8 87.2 90.2 92.3
18.6 16.7 14.2 12.8 9.8 7.7
64.3 71.2 76.6 82.2 85.8 93.2 100
92.1
7.9
Fig. 8 Main aromatics and C2–C4 olefins selectivities as a function of
H/Ceff ratio for co-CFP of pine wood and methanol at 450 ◦C. (a) ꢀ
Benzene, ᭡ Toluene,
Xylene, ᭜ Naphthalene; (b) ꢁ Ethylene, ꢀ
᭹
10.8
32.2 24.6 21.8 20.2 16.9 18.0
3.4 2.9 2.5 3.1 2.4 1.5
33.2 48.6 51.0 51.1 53.6 52.2
6.5
6.7
5.8
5.8
4.5
3.3
15.6
1.6
Propylene, Butenes, ᭛ Butadiene.
᭺
Toluene
Ethyl-benzene
p-Xylene and
m-Xylene
o-Xylene
Benzofuran
Indene
56.5
3.3.2 Effect of hydrogen to carbon effective (H/Ceff) ratio
at 500 ◦C. The product carbon yields and selectivities as a
function of H/Ceff ratio for co-CFP of pine wood and methanol
at 500 ◦C are shown in Fig. 9 and 10 and Table 6. It can be
seen from Fig. 9 that the unidentified compounds, CO and coke
yields decrease with the increasing H/Ceff ratio, while C2–C4
olefins, CO2 and methane yields increase significantly. Aromatic
yield is relatively constant at around 10% when the H/Ceff ratio
increases from 0.11 to 1.15. The aromatic yield decreases to
5.5% with further increase of the H/Ceff ratio to 2. As shown in
Fig. 10, xylene selectivity increases with increasing H/Ceff ratio,
and toluene selectivity decreases. Propylene selectivity increases
with increasing H/Ceff ratio. Ethylene selectivity decreases non-
linearly with the increasing of the H/Ceff ratio, whereas butenes
selectivity shows the opposite trend and increases non-linearly.
These non-linear curves indicate that the products are affected
by the co-feeding, and again a synergistic effect occurs at 500 ◦C.
4.8
4.3
2.6
1.1
7.7
8.2
2.2
2.4
0.4
4.4
9.2 11.4
9.3 11.3
0.6 0.4
8.5 11.6
9.5
0
13.6
0
1.0
3.0
0.3
4.5
1.0
3.8
0.2
3.5
Phenol
0.2
2.8
0
0.6
Naphthalene
Olefin selectivity
Ethylene
Propylene
Butenes
0
54.9 37.9 30.9 23.2 19.6 16.1
36.0 40.1 44.4 48.7 50.3 51.4
7.3 19.9 21.3 24.9 26.4 27.6
18.0
50.2
25.9
5.9
Butadiene
1.8
2.1
3.4
3.2
3.7
4.9
Fig. 7 Product yields as a function of H/Ceff ratio for co-CFP of pine
wood and methanol at 450 ◦C. Key: (a) ꢀ Aromatics, ᭡ C2–C4 olefins,
C compounds, ᭜ Unidentified, * Petrochemicals; (b) ꢁMethane, ꢀ
᭹
5
CO2, CO, ᭛ Coke.
᭺
yield a straight line with increasing H/Ceff ratio. This synergistic
effect of co-feeding is very apparent in the aromatic yield. The
aromatic yield is 5.9% for the only pine wood run and 11.1% in
the only methanol run. However, at the intermediate value of
H/Ceff = 1.05, a maximum yield of 21.4% aromatics is realized.
This result indicates that the aromatic yield is enhanced by co-
feeding methanol and is not purely additive. The unidentified
oxygenates yield decreases from 18.6% at H/Ceff = 0.11 to
Fig. 9 Product yields as a function of H/Ceff ratio for co-CFP of pine
wood and methanol at 500 ◦C. Key: (a) ꢀ Aromatics, ᭡ C2–C4 olefins,
C compounds, ᭜ Unidentified, * Petrochemicals; (b) ꢁMethane, ꢀ
᭹
5
CO2, CO, ᭛ Coke.
᭺
3.3.3 Effect of the total space velocity at constant H/Ceff
ratio. Fig. 11 and 12 show the product carbon yields and
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The Royal Society of Chemistry 2012
Green Chem., 2012, 14, 98–110 | 103
©

Table 6 Detailed product yields and selectivities for co-CFP of pine
wood and methanol at various H/Ceff ratios and 500 ◦C. Aromatic
selectivity is defined as the moles of carbon in the product divided by the
total moles aromatic carbon. Olefin selectivity is defined as the moles of
carbon in the product divided by the total moles olefin carbon
Table 7 Detailed product yields and selectivities for co-CFP of pine
wood and methanol at various total space velocities, H/Ceff = 1.05 and
450 ◦C. Aromatic selectivity is defined as the moles of carbon in the
product divided by the total moles aromatic carbon. Olefin selectivity is
defined as the moles of carbon in the product divided by the total moles
olefin carbon
H/Ceff ratio (mol/mol)
Total WHSV (h-1)
Compound
0.11
0.51
0.74
1.15
0.18
0.27
0.44
2.00
0
Compound
0.27
0.63
1.33
450
0.65
0.68
0.98
Pine wood WHSV (h-1)
Methanol WHSV (h-1)
Total WHSV (h-1)
Overall yields
Aromatics
0.41
0
0.41
0.24
0.08
0.33
0.28
0.18
0.46
0.35
T/◦C
450
0.12
450
0.28
0.35
5.5
Pine wood WHSV (h-1)
WHSV of co-feeding alcohol (h-1)
H/Ceff (mol/mol)
Overall yields
Aromatics
0.15
1.05
0.35
1.05
10.5
5.4
0.3
10.3
11.1
1.2
10.6
13.5
1.3
9.6
21.1
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
CO2
CO
34.6
1.1
31.8
8.0
17.3
21.8
12.7
91.5
8.5
1.8
41.9
11.0
21.5
21.0
2.9
98.3
1.7
100
17.1
27.6
2.4
21.4
26.3
3.7
18.9
21.5
2.8
43.2
1.3
16.2
2.1
7.7
25.6
31.7
83.3
16.7
64.3
22.6
4.3
9.8
24.0
24.6
85.3
14.7
72.0
25.4
5.5
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
CO2
CO
14.1
23.7
20.1
88.7
11.3
76.2
47.1
2.2
6.6
51.4
1.5
7.1
Coke
4.6
Total balance
Unidentified
Theoretical petrochemical
yield
Aromatic selectivity
Benzene
8.9
9.4
12.8
16.4
78.2
21.8
80.8
Coke
23.6
88.4
11.6
82.2
17.8
87.2
12.8
82.2
83.9
Total balance
Unidentified
Theoretical petrochemical yield
Aromatic selectivity
Benzene
15.3
34.7
4.5
24.1
3.5
11.7
28.5
2.2
28.8
0.9
10.6
27.7
2.3
33.6
0.8
10.6
26.9
1.9
41.8
7.6
0
2.8
1.2
0.5
6.7
9.7
19.3
2.5
43.3
7.7
4.4
0
11.0
0
2.2
Toluene
3.8
16.5
1.8
49.8
9.6
5.8
20.2
3.1
51.1
11.4
1.0
4.3
21.0
3.6
51.6
9.0
Ethyl-benzene
p-Xylene and m-Xylene
o-Xylene
Toluene
Ethyl-benzene
p-Xylene and m-Xylene
o-Xylene
Benzofuran
Indene
Styrene
3.7
1.6
5.2
9.0
6.2
7.7
Benzofuran
Indene
Phenol
1.8
0.5
7.0
0.2
3.3
1.5
2.0
1.0
1.7
0.8
13.2
0.5
3.0
3.8
0.2
3.5
Phenol
Naphthalene
Olefin selectivity
Ethylene
Propylene
Butenes
7.7
10.8
8.6
Naphthalene
Olefin selectivity
Ethylene
Propylene
Butenes
2.9
49.0
37.8
7.0
33.2
41.9
20.9
4.0
26.5
44.1
24.8
4.6
24.1
46.3
25.5
4.1
20.2
51.5
24.9
3.4
24.3
52.9
19.5
3.3
23.2
48.7
24.9
3.2
24.3
48.3
24.1
3.3
Butadiene
6.2
Butadiene
Fig. 11 Product carbon yields of co-CFP of pine wood and methanol
at different total WHSV values, H/Ceff = 1.05 and 450 ◦C. Key: (a) ꢀ
Fig. 10 Main aromatics and C2–C4 olefins selectivities as a function
of H/Ceff ratio for co-CFP of pine wood and methanol at 500 ◦C. (a)
Aromatics, ᭡ C –C olefins,
C compounds, ᭜ Unidentified; (b) ꢁ
᭹
2
4
5
ꢀ Benzene, ᭡ Toluene, Xylene, ᭜ Naphthalene; (b) ꢁ Ethylene, ꢀ
᭹
Methane, ꢀ CO2, CO, ᭛ Coke.
᭺
Propylene, Butenes, ᭛ Butadiene.
᭺
yields and selectivities for co-CFP of pine wood and methanol
at different total space velocities.
selectivities of co-CFP of pine wood and methanol at different
total WHSV with a constant H/Ceff ratio of 1.05 at 450 ◦C.
It can be seen from Fig. 11, lower total WHSV favors C2–C4
olefins and coke productions, while higher WHSV produces
more CO and unidentified oxygenates. The aromatic and total
petrochemical yields go through a maximum value of 21.4% and
51.4% at a WHSV of 0.63 h-1, respectively. The aromatic and
olefin selectivities are relatively constant over the WHSV range
tested, with the exception of toluene and butenes that increase
slightly with WHSV. Table 7 shows the detailed product carbon
3.3.4 Isotopic labelling studies of co-catalytic fast pyrolysis
of pine wood and methanol. Co-CFP of 12C pine wood and
isotopically labeled 13C methanol was conducted at 450 ◦C to
determine how methanol enters the hydrocarbon pool. The
WHSV values of 12C pine wood and 13C methanol were 0.30
h-1 and 0.29 h-1, respectively. The H/Ceff ratio of the mixture
was 0.97. The mass spectra of the most abundant products
are shown in Fig. 13. The fragmentation patterns for the pure
104 | Green Chem., 2012, 14, 98–110
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The Royal Society of Chemistry 2012
©

Fig. 12 Main aromatics and C2–C4 olefins selectivities of co-CFP of
pine wood and methanol at different total WHSV values, H/Ceff = 1.05
and 450 ◦C. (a) ꢀ Benzene, ᭡ Toluene, Xylene, ᭜ Naphthalene; (b)
᭹
ꢁ Ethylene, ꢀ Propylene, Butenes ᭛ Butadiene.
᭺
12C or pure 13C compounds are shown in black and white,
respectively. The spectra of the product obtained during the co-
feeding experiment are shown in grey. The results show that
all the main products are a mixture of 12C and 13C labeled
carbons. The distribution of carbon in benzene is a random
mixture of the 12C and 13C carbons. However, the distributions of
carbon within the other aromatics show trends. The distribution
of toluene and xylene are both shifted to the higher masses.
This indicates that a randomly distributed benzene molecule
was preferably alkylated by a 13C-containing radical over a 12C-
containing radical. Naphthalene shows the opposite trend as
its spectrum is shifted toward the lower masses. This shows
that the rate of naphthalene formation from the pine wood is
higher than that from the methanol. The methyl naphthalene is
not as shifted as the naphthalene, which shows that the methyl
group probably also came from methanol, similar to toluene and
xylene. The olefin compounds spectra also show obvious trends.
When taking into account the overlap of the fragmentation
peaks, the ethylene appears to be composed of more 12C than 13
C
carbon, while propylene and butenes show more 13C carbon. In
summary, 12C and 13C are distributed in all the hydrocarbon
product molecules. Benzene is a random mixture of the 12C
and 13C carbons, whereas naphthalene is formed much faster
from the carbon of pine wood than methanol. However, their
alkylated products were preferably alkylated by a 13C-containing
radical over a 12C-containing radical. This indicates that the
methanol enters zeolite catalytic process of biomass and it is
feasible to use feeds with high H/Ceff ratio to provide hydrogen
to the hydrocarbon pool for biomass conversion.
Fig. 13 Isotopic distributions for benzene, toluene, xylene, naphtha-
lene, 1-methyl naphthalene, ethylene, propylene and 1-butene from the
co-CFP of 12C pine wood and 13C methanol. Pure 12C and 13C mass
spectra for the given molecules are shown in black and white, respectively.
The co-feeding run results are shown in◦ grey. Reaction conditions:
catalyst, ZSM-5; reaction temperature, 450 C; WHSV of 12C pine wood,
0.30 h-1; WHSV of 13C methanol, 0.29 h-1; the hydrogen to carbon
effective (H/Ceff) ratio, 0.97; helium fluidizing flow rate, 1200 mL min-1;
reaction time, 30 min.
and the best synergistic effect. The product carbon yields and
selectivities of co-CFP of◦pine wood and the various alcohols
at H/Ceff = 1.25 and 450 C are listed in Table 8. As shown in
the table, the product selectivities of co-CFP of pine wood and
1-propanol, 1-butanol and 2-butanol are very similar, but there
is a great difference with co-feeding pine wood and methanol,
especially in aromatic selectivities. Co-conversion of pine wood
and methanol gave 62.9%, 5.8% and 16.9% selectivities of xylene,
benzene and toluene, respectively. Co-conversion of pine wood
with other alcohols gave about 39.2–40.2%, 10.4–11.0% and
38.6–39.3% ofxylene, benzene andtoluene, respectively. This can
be explained by the fact that methanol produced more methyl
radicals than other alcohols at the same H/Ceff ratio. Thus
more benzene and toluene molecules were alkylated to xylene
molecules.
3.4 Co-catalytic fast pyrolysis of other alcohols
Fig. 14 and Table 8 shows the petrochemical yield of co-CFP of
pine wood and other alcohols at H/Ceff = 1.25 and 450 ◦C.
The “calculated” values for the mixtures were found by a
weighted average of the yields from CFP of pine wood and
the alcohol separately. As shown in the figure, CFP of pine
wood produced 10.7% hydrocarbon yield, while methanol, 1-
propanol, 1-butanol and 2-butanol gave 71.5%, 86.8%, 86.3%
and 90.3% of hydrocarbon yield, respectively. The co-feeding
of pine wood and methanol yielded the lowest amount of
petrochemicals (58.7%), while co-feeding of pine wood and 2-
butanol produced the highest carbon yield of 65.2%. However,
compared with their calculated values, co-CFP of pine wood
and methanol gave the highest increase of hydrocarbon yield
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Green Chem., 2012, 14, 98–110 | 105
©

Table 8 Detailed product yields and selectivities for CFP of pine wood and methanol, 1-propanol, 1-butanol and 2-butanol at H/Ceff = 1.25 and
450 ◦C. Aromatic selectivity is defined as the moles of carbon in the product divided by the total moles aromatic carbon. Olefin selectivity is defined
as the moles of carbon in the product divided by the total moles olefin carbon
Co-feeding alcohol
Compound
Pine wood
Methanol
1-Propanol
1-Butanol
2-Butanol
Pine wood WHSV (h-1)
WHSV of co-feeding alcohol (h-1)
Total WHSV (h-1)
H/Ceff ratio (mol/mol)
Overall yields
Aromatics
C2–C4 olefins
C5 compounds
Petrochemicals
Methane
0.35
0
0.35
0.11
0
0.20
0.36
0.56
1.25
0
0.24
0.34
0.58
1.34
0
0.30
0.34
0.64
1.27
0
0.29
0.35
0.64
1.31
0.35
0.35
2.00
0.34
0.34
2.00
0.34
0.34
2.00
0.35
0.35
2.00
5.9
4.3
0.5
10.7
0.6
11.1
52.6
7.9
71.5
4.5
21.1
32.9
4.7
58.7
2.1
13.3
66.2
7.3
86.8
0.2
16.3
43.3
4.6
64.3
0.4
15.2
60.7
10.3
86.3
0.2
17.2
38.4
6.0
61.5
0.4
15.2
67.2
7.9
90.3
0.2
15.6
44.6
5.0
65.2
0.4
CO2
CO
Coke
8.9
8.9
5.1
2.1
92.1
100
71.5
7.2
7.7
14.5
90.2
85.8
68.4
0.2
0.4
1.6
89.2
100
86.8
2.3
6.5
10.7
84.1
87.5
73.5
0.2
1.1
1.0
88.7
100
86.3
2.2
6.9
14.3
85.5
86.2
71.4
0.2
0.5
1.0
92.1
100
90.3
2.8
7.6
12.8
88.8
86.9
75.0
19.7
41.6
81.4
64.3
16.6
Total balance
Theoretical (Toluene)
Experimental/theoretical
Aromatic selectivity
Benzene
10.8
32.2
3.4
33.2
4.8
3.3
15.6
1.6
56.5
9.5
0
5.8
16.9
2.4
53.6
9.3
11.8
43.1
3.6
31.0
7.0
11.0
39.3
3.7
32.8
6.4
11.5
40.8
3.5
27.9
6.0
10.6
38.7
4.2
34.2
6.0
12.0
43.8
3.7
30.5
6.7
10.4
38.6
4.2
34.0
6.2
Toluene
Ethyl-benzene
p-Xylene and m-Xylene
o-Xylene
Benzofuran
4.3
0.6
0.1
0.5
0.1
0.5
0.1
0.4
Indene
Phenol
2.6
1.1
13.6
0
8.5
0.2
2.5
0.2
2.3
0.5
2.0
0.1
2.5
0.2
2.3
0.2
2.6
0.5
Naphthalene
Olefin selectivity
Ethylene
Propylene
Butenes
7.7
0
2.8
0.8
3.6
0.6
3.1
0.7
3.1
54.9
36.0
7.3
18.0
50.2
25.9
5.9
19.5
50.3
26.5
3.7
10.9
55.7
29.6
3.8
12.8
54.5
28.6
4.1
12.2
52.7
31.4
3.7
12.4
53.8
29.8
4.0
10.0
53.8
32.6
3.6
13.4
51.5
30.9
4.2
Butadiene
1.8
Fig. 15 The petrochemical yield as a function of H/Ceff ratio at
450 ◦C and 500 ◦C. Key: Petrochemical experimental yield at reaction
temperature of ꢀ450 ◦C and * 500 ◦C; ᭡ Theoretical yield; Experimen-
Fig. 14 The petrochemical yield of co-CFP of pine wood and methanol,
1-propanol, 1-butanol and 2-butanol at H/Ceff = 1.25 and 450 ◦C. Key:
tal/theoretical ratio at reaction temperature of 450 ◦C, ᭛ 500 ◦C.
᭺
Pure pine wood;
Experimental values for co-feeding of pine
wood with alcohol;
with alcohols;
Calculated values of co-feeding of pine wood
Pure alcohol.
methanol at 450 ◦C produced much more petrochemicals than
that at 500 ◦C, and the gap increases with increasing H/Ceff
ratio. The theoretical yields of dry pine wood and methanol
are calculated by assuming toluene as the reaction hydrocarbon
product. The calculating equations are shown in eqn (2) and (3).
4. Discussions
4.1 Comparison of products of co-catalytic fast pyrolysis of
pine wood and methanol at 450 ◦C and 500 ◦C
Fig. 15 shows the petrochemical yield as a function of H/Ceff
ratio for co-CFP of pine wood and methanol at 450 ◦C and
500 ◦C. As shown in the figure, co-CFP of pine wood and
4
41.8
11
10.9
11
(2)
C3.8H5.8O2.7
→
C7H8 +
CO +
H2O
11
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From the isotopic distribution of benzene, we can see that
the amount of 12C and 13C is almost the same in the benzene
molecule. The toluene and xylene are probably produced from
alkylation of benzene. However, their isotopic distributions
are not normal distributions and lean to 13C. Combining this
with benzene’s isotopic distribution, it seems that almost all
the methyl radicals for benzene alkylation are from methanol.
Our previous study showed that naphthalene is formed by
monocyclic aromatics with oxygenated fragments that are the
derived products of biomass pyrolysis.78 The isotopic distri-
bution of naphthalene, shown in Fig. 15, agrees with this
conclusion because the distribution is skewed to 12C. In this
study, the naphthalene is produced by randomly formed benzene
combiningwiththe oxygenated fragments (usuallythat are based
on a furanic structure) that are the derived products of biomass
pyrolysis. Methanol makes almost no naphthalene in the sep-
arate and co-feeding it with pine wood runs. Compared with
the isotopic distribution of naphthalene, 1-methyl naphthalene
distribution leans to 13C by 1 carbon. Thus methanol is also able
to alkylate naphthalene.
1
3
(3)
CH4O → C7H8 + H2O + H2
7
7
The theoretical yield of dry pine wood is about 67% carbon
according to eqn (2), while that of methanol is 100% carbon
shown in eqn (3). The pine wood used in this study contains
about 4% moisture, thus the theoretical yield of pine wood based
on the feed is 64.3%. The theoretical yield plot in Fig. 15 is drawn
according to the theoretical yields that would be achieved if all
the carbon in the biomass is converted into toluene, water, and
carbon monoxide. Data points are added to this based on our
previous study, which used ten different feedstocks.58
Also included in Fig. 15 is the ratio of experimental to
the theoretical (experimental/theoreteical) yield of the different
feedstocks. This ratio allows us to determine how close to the
theoretical carbon yield we are for each experiment. At 450 ◦C,
this ratio increases non-linearlyfrom16.6%atH/Ceff = 0.11(only
pine wood) to about 70% at H/Ceff = 1.25. Further increasing
the H/Ceff ratio above 1.25 only gives a small change in the
experimental/theoreteical ratio. This result suggests that the co-
feeding of wood and methanol allows us to more efficiently
convert the carbon in these feedstocks into petrochemicals by
co-feeding rather than feeding the two reactants separately.
Furthermore, the H/Ceff ratio = 1.25 is an inflection point,
where the petrochemical yield does not increase as rapidly.
This result is consistent with our previous study in which we
catalytically deoxygenated ten biomass-derived feedstocks with
different H/Ceff ratios with a zeolite catalyst and found an H/Ceff
ratio = 1.2 to be the inflection point.58 This suggests that the
amount of methanol co-fed with pine wood should be enough
to bring the mixtures to an H/Ceff ratio of 1.25. It should
be noted that co-CFP can not run at high temperature since
methanol would be converted into CO, CO2, methane and coke
at high temperature and pine wood would be converted into
coke and unidentified oxygenates with this catalyst. The suitable
temperature for co-CFP of pine wood and methanol is 450 ◦C.
Although co-feeding pine wood and methanol at 450 ◦C
produced much more petrochemicals than reacting the two feeds
at 450 ◦C separately, the petrochemical yield of co-feeding is still
lower than running the two feeds at ◦their optimal temperatures
4.3 Economic potential
In Section 3.3.1 it was shown that co-feeding pine wood and
methanol at 450 ◦C increases the total aromatic yield. However,
the total petrochemical yield is always highest for the pure
compounds. A simple economic analysis is done to determine
whether co-feeding methanol with wood is economically ben-
eficial with the conditions used in this paper. The economic
potential (EP) was used to evaluate the potential economic
benefit of co-feeding wood with methanol. The EP is calculated
by eqn (4):
EP = Rprice of products - Rprice of feeds
(4)
EP is calculated for the different temperatures used in
this paper. The scale of the refinery was set at 250 ,000 tons
products/year for all these calculations. Wood and methanol
prices usually range between $20–100/ton1 and $260–360/ton,79
respectively. Five groups of price combinations were used for
comparison to allow us to determine the sensitivity of these
different scenarios with feedstock prices. These five groups
are (a) low methanol price and low wood price, (b) high
methanol price and high wood price, (c) low methanol price
and high wood price, (d) high methanol price and low wood
price and (e) medium methanol price and medium wood
price. These figure groups of price combinations are shown
in Fig. 16a–e. Each figure also shows the results with pure
wood and pure methanol. The product prices were based on
the following values: $889/ton-benzene, $735/ton-toluene,
$1521/ton-styrene, $690/ton-indene, $690/ton-naphthalene,
$804/ton-mixed xylenes, $970/ton-ethylene, $1212/ton-
propylene, $1200/ton-butenes, $2270/ton-butadiene and
$690/ton-gasoline (C5 compounds).79
◦
(pine wood: 600 C; methanol: 400 C). Therefore, to be more
effective at co-utilization of wood and methanol, the catalyst
should be designed to decrease the optimal temperature of pine
wood CFP or increase that of methanol conversion.
4.2 Chemistry of co-catalytic fast pyrolysis of pine wood and
methanol
Co-feeding of 12C pine wood and 13C methanol results show
that all the hydrocarbon products contained 12C and 13C
in their molecules. Our previous results observed this same
phenomenon with a 1 : 1 w/w mixture of pure 12C and 13C
glucose as reactants.78 This suggests that the feeds (or their
derived/pyrolysis products) enter the zeolite catalyst, lose their
identity within a hydrocarbon pool and combine stochastically
with other molecules. This proves that adding hydrogen to
biomass conversion process via co-feeding it with other higher
H/Ceff ratio feeds is feasible.
As can be seen from Fig. 16, co-feeding pine wood and
methanol at a reaction temperature of 450 ◦C gives a higher EP
than at a reaction temperature of 500 ◦C for all price scenarios
when the H/Ceff ratio of the feed is greater than or equal to
0.50. When wood price is low (Fig. 16a), the EP is highest when
pure wood is added to the reactor. When wood price is high,
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Green Chem., 2012, 14, 98–110 | 107
©

of pine wood and methanol has much higher EP than that of
running them separately. However, the EP of co-feeding pine
wood and methanol is still lower than that of runnin◦g them
separately at their optimal conditions (pine wood: 600 C and
0.35 h-1; methanol: 400 ◦C and 0.35 h-1).
5. Conclusions
In this work, we conducted catalytic fast pyrolysis (CFP) of
pine wood, alcohols (methanol, 1-propanol, 1-butanol and 2-
butanol) and their mixtures with ZSM-5 catalyst in a fluidized
bed reactor. The maximum petrochemical yield when pine wood
was the feedstock was 23.7%, which occurred at 600 ◦C and
0.35 h-1. Both the coke and unidentified oxygenates yields
decrease with increasing temperature, whereas the coke yield
decreases and the unidentified oxygenates yield increases with
increasing WHSV. The maximum petrochemical yield when
◦
methanol was the feed was 80.7% and occurred at 400 C and
0.35 h-1. The yields of petrochemicals and unidentified com-
pounds decrease with increasing temperature, and the yields of
methane, CO2, CO and coke increase with the increasing temper-
ature. The petrochemical yields increase rapidly at lower WHSV,
while CO, CO2, methane and coke yields show the opposite
trend.
CFP of pine wood and methanol◦ mixtures with different
◦
ratios were tested at 450 C and 500 C. The results show that
the petrochemical yield increases non-linearly with increasing
H/Ceff ratio of the feed, and more petrochemicals can be
produced from wood when methanol is added to the CFP
process. H/Ceff = 1.25 is an inflection point in this process,
where the petrochemical yield begins to reach an asymptote.
This suggests that the amount of methanol co-fed with wood
should be enough to bring the mixtures to an H/Ceff ratio of
1.25. Adding more methanol would be a waste of methanol and
increase the cost of the process, since methanol price is much
higher than wood’s. Co-CFP of pine wood and other alcohols
also increases the petrochemical yield, whereas co-CFP of pine
wood and methanol gave the highest increase of petrochemical
yield.
The isotopic studies of CFP with 12C methanol and 13C pine
wood showed that the products were produced from mixtures
of methanol and pine wood. Benzene was made from random
mixtures of methanol and pine wood. Propylene and butenes
were produced more from methanol than wood. Naphthalene
contained more 12C and therefore were produced more from pine
wood than methanol. This indicates that it is feasible to use feeds
with high H/Ceff ratio to provide hydrogen to the hydrocarbon
pool for biomass conversion.
In summary, the petrochemical yield produced by CFP of
biomass can be enhanced by co-feeding it with feeds that have
a high H/Ceff ratio. In the co-feeding process, the two feeds
can be converted together within the zeolite and have a positive
synergistic effect. This study provides insights into how biomass
resources can be used more efficiently to produce renewable
petrochemicals. It is likely that future advances in the design of
improved catalysts combined with reaction engineering will lead
to the design of even more efficient processes for the production
of renewable fuels and chemicals.
Fig. 16 Economic potential (EP) for CFP and co-CFP of wood and
methanol as a function of H/Ceff ratio at different feed prices. Price for
wood (W) and methanol (M) ($/metric ton): (a) W = 20, M = 267; (b)
W = 100, M = 334; (c) W = 20, M = 334; (d) W = 100, M = 267; (e) W =
60, M = 300. Key: ꢀ Co-feeding of pine wood and methanol at 500 ◦C;
᭜ Co-feeding of pine wood and methanol at 450 ◦C; ᭡ Pine wood at
600 ◦C; Methanol at 400 ◦C.
᭹
co-feeding pine wood and methanol at 450 ◦C made the EP
increase non-linearly with increasing H/Ceff ratio (see Fig. 16(b,
d and e)). This considerable curvature indicates that co-feeding
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Acknowledgements
The authors are grateful for the U. S. National Sci-
ence Foundation (Grant No. EFRI-0937895), National Ba-
sic Research Program of China (973 Program, Grant No.
2010CB732206), National Natural Science Foundation of China
(Grant No. 51076031), China Scholarship Council and the
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