Fluidized bed fast pyrolysis of corn stover: Effects of fluidizing gas flow rate and composition

ABSTRACT

Fast pyrolysis of corn stover was carried out in a pilot scale fluidized bed reactor in nitrogen atmosphere. The effects of varying gas flow rates at optimum reaction temperature of about 500ºC and feed size of < 1.0 mm on yield and composition of bio-oil, char and gas were investigated. The results for three runs with flow rate of gas of 45, 80 and 70 L/min, respectively, were obtained. The distribution of pyrolysis products was calculated gravimetrically by mass balance and corrected with optimization mass model using proximate and ultimate analysis of feedstock and pyrolysis products. The maximum yield of bio-oil (52 wt%) was obtained in run 3 with flow rate of gas of 70 L/min having heating value of 21.20 MJ/kg. GC-MS analysis identified the major chemical compounds present in the bio-oil which were levoglucosan, hydroxyl acetaldehyde, acetol, acetic acid, phenols, 2-methyl-2-cylopenten-1-one, guaiacol, 2(5H)-furanone, fufuryl alcohol, p-cresol and 2-ethyl alcohol. The bio-oil produced from run 3 had higher amounts of aromatic hydrocarbons, non-methoxylated phenolics, levoglucosan and smaller amounts of acids. On the other hand, bio-oil obtained from TGRP experiments had low value of total acid number (57.73 mg of KOH/g) indicating less oxygenating compounds with greater heating value in the product.

KEYWORDS:

• Fast pyrolysis
• corn stover
• pilot scale
• bio-oil
• fluidized bed reactor
• GC-MS analysis
• Tail gas reactive pyrolysis (TGRP)

Acknowlegement

The authors are highly thankful to USDA ERRC Wyndmoor PA, USA and Higher Education Commission of Pakistan for providing the technical and financial support for this research work.

Additional information

Notes on contributors

Najaf Ali

Najaf Ali is Ph.D. Chemical Engineer, research area pyrolysis of biomass in fluidized bed reactor. He is working as a Assistant Professor/ Coordinator of Chemical Engineering Department at NFC Institute of Engineering and Fertilizer Research, Faisalabad Pakistan. He has 23 year of experience in the field of Chemical Engineering and Administration.

Muhammad Ashraf

Muhammad Ashraf is Ph.D. Chemical Engineer, from Turkey. He is working as a In Charge / Head Academics of NFC Institute of Engineering and Fertilizer Research, Faisalabad Pakistan. He has 31 year of experience in the field of Chemical Engineering and Administration.

Khurram Shahzad

Khurram Shahzad is Ph.D. Chemical Engineer, research area emission control by indigenous coal combustion in combustor reactor. He is working as  Associate Professor. He has 15 year of experience in the field of Chemical Engineering and Administration.

Mahmood Saleem

Mahmood Saleem is Ph.D. Chemical Engineer, Graz University of Technology, Austria. He is working as  a Director/ Professor of Center for Coal Technology, University of the Punjab, Lahore Pakistan. He has 24 year of experience in the field of Chemical Engineering and Administration.

Arshad Chughtai

Arshad Chughtai is Ph.D. Chemical Engineer, University of Birmingham, UK. He was ex-Professor of Institute of Chemical Engineering and Technology, University of the Punjab, Lahore Pakistan.