Co-gasification of oil palm biomass in a pilot scale downdraft gasifier

Kelechi E Anyaoha,Ruben Sakrabani,Kumar Patchigolla,Abdul M Mouazen

doi:10.1016/j.egyr.2020.07.009

Kelechi E Anyaoha, Ruben Sakrabani + Show 2 more

Open Access

https://doi.org/10.1016/j.egyr.2020.07.009

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Journal: Energy Reports	Publication Date: Jul 22, 2020
Citations: 12	License type: cc-by

Affiliation: Cranfield University, Ghent University

Abstract

The present study focused on co-gasification of empty fruit bunch (EFB), mesocarp fibre (MF) and palm kernel shell (PKS) in a 75 kWth pilot scale downdraft gasifier for possible synergic reactions between the biomass. A series of experiments was carried out using equal blend of EFB, MF, and PKS (particle sizes of 14 and 6.7 mm) and equal blend of MF and PKS. Advanced infrared multi-gas analyser, and thermal conductivity gas analyser were employed to measure the produced gases. The elemental compositions of the raw biomass, ash and slag generated were determined using Scanning Field Emission Gun Scanning Electron Microscopy with accelerating voltage 20.0 kV and working distance 6 mm and the measurements processed using AztecEnergy V2.2 software. The co-gasification of blend of EFB, MF, and PKS, compared to the blend of MF and PKS led to higher gas yield (4.82 and 3.47 m3/kg_biomass), cold gas efficiency (16.2 and 13.37%), and carbon conversion efficiency (56.3 and 34.18%), respectively. When compared to particle size of 14 mm, the PKS of particle size of 6.7 mm in the EFB/MF/PKS blend increased the lower heating value and the higher heating value of the producer gas by 20% and 20.3%, respectively, and the residue yield was 18.6% less. The overall result has provided evidence on the importance of co-gasification of biomass especially EFB, MF and PKS, which will result in increased utilization of EFB.

Highlights

Ash content is an important property of biomass, which influences decisions in biomass thermal conversion operations
There is consistency in the higher heating value (HHV) and lower heating value (LHV) for empty fruit bunch (EFB), mesocarp fibre (MF), and palm kernel shell (PKS) with values decreasing in the following order: MF>PKS>EFB
The results from co-gasification of EFB, MF and PKS showed that the addition of EFB to the blend of MF and PKS led to higher gas yield, cold gas efficiency and carbon conversion efficiency, compared to the blend of only MF and PKS

Summary

Introduction

Ash content is an important property of biomass, which influences decisions in biomass thermal conversion operations. Challenges associated with ash in thermal conversion system are bed agglomeration, slagging on the furnace, fouling of heat transfer systems (Kuprianov et al, 2018; Cotton et al, 2014). These will reduce system efficiency and result in increased operational cost (Kuprianov et al, 2018; Aziz et al, 2016). The utilization of biomass in thermal conversion operation will lead to increase in biomass ash generation. Increase in the utilization of biomass for energy generation would require the use of a blend

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