MICROWAVE ASSISTED CATALYTIC DEPOLYMERIZATION OF BIOMASS AND
PRODUCT CHARACTERIZATIONP. Gupta1, B Behera1, V. Bhanu Prasad1, Jagdish Kumar1, and Y.K.Sharma1, S.S. Ray1
1CSIR-Indian institute of Petroleum, Dehradun-248005,Indiae-mail: babitab@iip.res.in, +91-135-2525771

Abstract
Microwave assisted Pyrolysis(MAP) of biomass is an important thermo-chemical depolymerisation technology which
could produce bio-oil quickly through decomposition. The traditional pyrolysis technology has the disadvantage of highenergy consumption and long reaction cycle. Therefore, it is a need to explore or establish a facile route for fast
depolymerisation of biomass to value added products for scientific significance. The pyrolysis of Biomass using
microwaves is a potential technology for the transformation of waste to high-value bio-energy materials. In literature effectof metal oxides, salts and catalysts were reported for studying product distribution.
In this paper, the influence of microwave heat rate, effect of catalysts and temperature on depolymerisation of
lignocellulosic bagasse were studied and profile of product distribution were examined with defferent catalysts. The Dataand informations will be useful for designing and optimising a process of pyrolytic depolymerisation of bagasse via
microwave heating technology.

Keywords: microwave pyrolysis, gas, bio-liquid, GC, nmr

1. Introduction
Decreasing fossil reserves, rising in oil prices, concerns
over the energy security, environmental impacts andsustainability have led to a global policy shift backtowards the use of biomass as a local, renewable
feedstock. Pyrolysis is an efficient thermochemical
process for the production of liquid bio fuels in absenceof oxygen [1]. Various efforts have been made tounderstand product pattern and quality of liquid bio fuels.
Microwave assited pyrolysis is an important process for
pyrolysis of biomassl. Moreover, the bio-fuel contain lessamountof
harmfulpolycyclicaromatichydrocarbons(PAHs) compared to fast pyrolysis oil[2]. As
biomass is a poor absober of microwave energy, theyield of bio-liquid from biomass without catalyst is very
low. Thus the depolymerisation of biomass needs asuitable catalyst with good microwave absorbing
capacity. Metal oxides, salts, catalysts, acids, alkali havebeen reported in literature for this purpose [3].
In this paper, the objective is to study the product pattern
and to screen a catalysts for low temp depolymerisationof biomass.

2. Materials and Methods
Raw bagasse used in this experiment was dried in ovenat 1050 C to remove the moisture content. A Milestone
microwave reactor (Milestone srl, Italy) with maximum
power input 1200W and frequency of 2.45GHz was usedfor microwave pyrolysis of bagasse. To determine theinfluence of different catalysts on the yield of bioliquid,
15gm of bagasse was premixed with 2gm of catalyst in a
microwave reactor under N2 gas purging. Reaction wascarried out at 1700C with 900W microwave power foreach run. The volatiles pyrolyzates were condesed after
passing through a water cooled condensor (at 5-100C)
and then collected. The biochar was left in a quartz flask
after pyrolysis.

Fig 1: Schemetic diagram of microwave pyrolysis
apparatus
The gaseous products were analyzed using Varian-CP3800-FAST-RGA GC equipped with a TCD detector.
Each sample was measured three times to get theaverage value. The bio-liquid were analyzed using

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

Avance-III Bruker 500MHz NMR spectrometer equippedwith 5mm BBFO Probe.

3. Results and Discussion
The depolymerization of lingo-cellulosic bagasse wasinvestigated in a microwave reactor. The percentage ofbio-liquid yield is highest for Cat3. The products arecharacterized by GC, NMR

Fig 2: Percentage of conversion and product pattern withfour different catalysts.

Fig 4:13C NMR spectra of Bio-liquid of four reactions.

Fig 5: Normalised gaseous distribution with different
catalysts

4. Conclusions

Fig 3: 1H NMR spectra of bio-liquid of four reactions

The normalized distribution of gases and bio-liquid are
calculated from GC and NMR. Cat-3 has highest yield ofbio-liquid. The percentage yield of H2 and methane isfound to be more for Cat-3. The bio-liquid contains more
oxygenated compounds for Cat 3 followed by Cat-2, Cat4 and Cat-1. The percentage of aromatics in bi-liquid ishighest for Cat-2 with a declining trend for Cat-4, Cat-3
and Cat-1.

Biomass depolymerization occurs at low temperatureusing microwave conditions. The products werecharacterized by GC and NMR techniques. The bio-liquid
for Cat-3 contains highest percentage of oxygenatedhydrocarbon, and while products from Cat-2 containhigher percentage of aromatics.

5. Acknowledgement
CSIR-IIP is acknowledged for providing support for theproject CSC-0116/WP-8

References[1] A. V. Bridgewater, G. V. C. Peacocke. Sustain.
Energy Rev. 4(2000)1-73.
[2] A. Dominguez, J. A. Menendez, M. Inguanzo, J. J.
Pis. Fuel Process. Tech. 86(2005)1007-1020.
[3] Y. Wan, P. Chen, Bo Zhang, C. Yang, Y. Liu, X. Lin,R. Ruan. J. Anal. Appl. Pyrolysis 86(2009)161-167.

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013