Improvement of Furfural Production From Concentrated
Pre-Hydrolysis Liquor (PHL) of a Kraft-Based Hardwood
Dissolving Pulp Production Process
M. Sarwar Jahan
Pulp and Paper Research Division, BCSIR
Laboratories, Dhaka1
2
Kraft-based dissolving pulp process
Cooking
Chemicals
Dissolvin
g pulp
(Cellulose
)
Cooking
chemical
recovery
Dissolved
hemicelluloses,
lignin
Dissolved
organics +
Inorganics
Pre-
hydrolysis
Kraft
pulpingBleaching
Wood
chips
PHL (PRE-HYDROLYSIS LIQUOR)
- Lignin: 1 wt%
- Acetic acid: 1 wt%
- Sugars: 5 wt% (mostly C-5 sugars)
3
BIOREFINERY CONCEPT
4
In addition to dissolving pulp (cellulose), other
products including lignin, acetic acid, sugars and
their derivatives can be produced.
Therefore, the pre-hydrolysis kraft-based
dissolving pulp production process fit well into
the forest biorefinery concept.
PHL: a potential feedstock for furfural production
Xylose/xylan is the dominant hemicelluloses in the
PHL of the hardwood dissolving pulp mill, but the
concentration of sugars are low.
Nanofiltration (NF) can be used to concentrate the
sugars in the PHL to be used for furfural production.
Presence of acetic acid in the PHL can be a source of
catalyst for furfural production.
Turning wastes to useful products, another revenue
source for the dissolving pulp mill 5
Furfural
6
Nylon 6.6
Resin
Pharmaceutical
industryPetroleum
industry
Traditional furfural production
Catalysts: H2SO4 , HCl
Feedstocks: solid agricultural, forest wastes
Corncobs Saw dust straw
7
Temperature (℃)residence
time
Xylose
concentration in
PHL (%)
Furfural
yield (%)
150 20 10.69 2.51
190 20 10.69 7.75
150 100 10.69 7.87
190 100 10.69 1.38
150 60 3.52 1.11
190 60 3.52 28.56
150 60 17.5 2.19
190 60 17.5 0.501
170 20 3.52 15.05
170 100 3.52 32.81
170 20 17.5 2.61
170 100 17.5 2.20
170 60 10.69 10.95
Optimization of furfural production from PHL
An increase in xylose concentration in the PHL decrease in
furfural yield
8
Addition of H2SO4 increased furfural yield.
Temperatu
re (℃)
residence
time (min)
C-5 sugars
concentration
in PHL (%)
H2SO4
added
(%)
Furfural
yield (%)
Sugar
conversion
(%)
Acetic acid
concentration
(g/L)
170 100 3.5 / 32.8 77.0 15.4
170 100 3.5 0.4 48.4 86.2 14.2
170 100 10.7 / 6.4 95.5 28.5
170 100 10.7 0.4 7.8 93.3 28.4
170 100 17.5 / 2.2 95.2 45.6
170 100 17.5 0.4 2.3 92.9 43.9
190 100 17.5 / 1.6 99.9 36.8
190 60 10.7 0.4 5.5 99.7 40.1
190 60 10.7 1 6.6 99.7 31.3
Addition of sulfuric acid to improve furfural
formation
9
X F D
Side
reactions
r1 r2
r3
Kinetics
Parallel kinetic model explains the furfural
formation process well for the PHL system10
11
Furfural yield and C-5 sugar conversion
PHL (11.1%) vs Xylose (10.7%)
Furfural yield from PHL is much lower than that from xylose
0
20
40
60
80
100
120
0 50 100 150 200
Fu
rfu
ral
yie
ld (
%)/
C-5
su
gar
co
nvers
ion
(%
)
Time (min)
Furfural-Xylose
Furfural-PHL
Sugar-Xylose
Sugar-PHL
Side reactions: with lignin.
Side reactions: with furfural, e. g. resinification.
Condensation: furfural with sugars or degradation products.
degradation
products
Possible side reactions associated with furfural in the PHL
system (H. Liu, et al., Bior, Techn., 2013,131:315-320.)
Side reactions
12
DECREASING SIDE REACTIONS AT A HIGH CONC. PHL
13
Continuous
removal as
generated
Removal by
resin
Removal by AC
(activated carbon)lignin
HAc
furfural
reduces side reactions (condensation et al.)
improves the performance of the
subsequent nano- filtration
recovers acetic acid
reduces side reactions
improves furfural yield
INTEGRATED PROCESS OF ACTIVATED CARBON(AC)
ADSORPTION, RESIN TREATMENT, AND SUGAR
CONCENTRATION/UTILIZATION
14
furfural or
xylitol
PHLAC
treated
PHL
Filter
cake
Regenerated AC
Filter
cake
Acetic acid
AC/ Resin-
treated PHL
Lignin
AC adsorption IER treatment filtration
Sugar
concentration/
membranefiltration
Regenerated
resin
Regeneration
of AC
Resin
Regeneration
CHARACTERIZATION OF PHL AND AC/RESIN
TREATED PHL
15
Compositions PHL
AC/ resin treated
PHL
Total sugar, % 4.91 4.14
Pentose % 3.52 2.91
Hexose % 1.39 1.23
Lignin, % 0.87 0.13
Acetic acid, % 1.04 0.46
Furfural, % 0.15 0.06
NANOFILTRATION FOR CONCENTRATING SUGARS OF
PHL
16
2.2
2.3
2.3
2.4
2.4
2.5
2.5
2.6
Monomeric sugarOligomeric sugar Total sugar
C/C
0
Fig. The C/C0 value of Concentration of sugars in concentrate and feedstock PHL (VRF
is 2.53, pressure is 600 psi)
The oligomeric sugars concentration was 2.52 times to that of the
feedstock PHL, while the monomeric sugars concentration was 2.34.
The concentration of total sugars after NF was 11.2%.
P
1. Autoclave 2. Blender 3. Liquid bleed valve 4. Pressure gage
5. Control box 6. Vapor bleed valve 7. Thermocouple
8. condenser 9. Cylinder
1
5
2
34
6
7
8
9
Steam Stripping for FurfuralProduction
17
FURFURAL, ACETIC ACID AND FORMIC ACID FROM
TREATED PHL (WITH CONTINUOUS PRODUCT REMOVAL)
18
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
0 10 20 30 40 50
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0 furfural yield
furfural concentration
acetic acid concentration
formic acid concentration
conc
entr
atio
n (g
/L)
time (min)
furfural yield (%)
Development of the furfural, acetic acid and formic acid conc. in the
condensate and furfural yield (180 ºC, 11.2% sugar PHL)
CONCLUSIONS
The integrated process of activated carbon adsorption,
IER adsorption and membrane filtration is a good
example of recovering lignin, acetic acid, and utilizing
sugars in the PHL
The lower furfural yield in a concentrated PHL was due
to side reactions (carbonization, condensation with
lignin/sugar, resinification, et al.)
19
CONCLUSIONS
20
Removal of lignin by AC adsorption and
continuous removal of generated furfural can
minimize the side reactions. A furfural yield of
41.8% was obtained for the concentrated PHL.
ACKNOWLEDGEMENT
21
THANK YOU
22
Top Related