The potential use of torrefied Nigerian biomass for combustion applications

Abstract

Many countries are seeking to expand their use of solid biomass for electricity and heat generation. Nigeria, too, is exploring its own potential energy crops and indigenous residues. The use of this biomass for energy production is, however, limited by factors such as high moisture content, low bulk and low energy density. This study examines the torrefaction and combustion properties of four readily available Nigerian woody biomass, Gmelina arborea, Terminalia superba, Nauclea diderrichii, Lophira alata and a residue, palm kernel expeller (PKE). They are considered for their suitability for use in large scale power stations, especially as pulverized fuels.The Fuels were torrefied at 270 and 290 o C for either 30 or 60 min, and assessed for pyrolysis and combustion characteristics in comparison to their untreated counterparts.Energy densities of the woods improved from 19.2-21.2 MJ/kg for the raw fuels to 21.5-24.6 MJ/kg for the torrefied fuels. The milling behaviour of the torrefied fuels improved upon torrefaction, especially for Nauclea; however, torrefaction had very little effect on the grindability of PKE. The apparent first order kinetics for pyrolysis were determined by thermogravimetric analysis (TGA). After torrefaction, the fuels become less reactive; Nauclea and Gmelina were the most reactive fuels, whilst PKE was the least reactive. The combustion behavior of selected fuels was visually examined in a methane air flame. This showed that torrefaction resulted in shorter ignition delay, shorter duration of volatile combustion and longer duration of char burn out.

Role of Primary Freeboard on Staged Combustion of Hardwood Pellets in a Fixed Bed Combustor

“…However, despite its potential for replacing fossil fuels, direct thermal conversion of biomass via combustion also requires continued insights into reducing or managing the resulting gaseous and particulate emissions as well as ash generation [4]. Whilst chemical and physical properties of biomass can significantly affect its utilisation [5], this paper addresses the role of process design (air staging) on important performance indicators such as temperatures, emissions and fuel consumption rates.…”

Bağ Budama Atığına Uygulanan İnert ve Oksidatif Torrefaksiyon İşleminin Karşılaştırılması

“…Tablo 4'de hem oksitleyici (hava) hem de inert (azot) ortamda torrefiye edilen BBA'dan elde edilen biyokömürlerin tutuşma sürelerinin düştüğü yani daha hızlı tutuştukları tespit edilmiştir. Tutuşma süresindeki azalmanın torrefaksiyon sonucu uzaklaşan nem ve biyokütlenin yapısında oluşan değişimlerden kaynaklanmaktadır [48][49].…”

OPTIMAL DESIGN OF ORGANIC RANKINE CYCLE POWER PLANTS FOR EFFICIENT UTILIZATION of BIOMASS ENERGY IN NIGERIA

“…That is notwithstanding other aforementioned agricultural residues, municipal wastes, and industrial wastes which have been reported substantial in quantity in Nigeria [24]. Apart from the studies aimed at assessing biomass energy potential in Nigeria, other authors have focused on experimental characterization of different biomass fuels to facilitate their practical applications in biomass power plants [25], [26], [27]. The legal perspectives on the challenges and prospects of converting organic wastes to electrical energy in Nigeria were the focus of [28], where the authors remarked that a coherent and explicit legal framework is required to promote biomass energy in the country.…”