https://search.dev.ndltd.org/etd/massey/oai:mro.massey.ac.nz:10179/2826
type: CreativeWork
name: Air gasification of woody biomass from short rotation forests : opportunities for small scale biomass-electricity systems : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Agricultural Engineering at Massey University, New Zealand
description: Downdraft gasification of short rotation forestry (SRF) biomass was investigated to identify opportunities for small scale biomass-electricity systems. Case studies were conducted in Kenya to identify these opportunities by (i) defining the energy demand and supply structure to identify markets; (ii) evaluating the biomass resources available; and (iii) identifying the availability of other facilities required for such a system. At the same time, the yield potential of 12 SRF species, planted in Palmerston North, New Zealand in small plots at 3470 stems/ha and harvested after 2, 3, 4 and 5 years was evaluated. Samples were collected from each species to determine their energy properties. Data on tree growth, yield, and biomass properties were used to develop two multi-objective indices - the relative yield index (RYI) and the fuelwood value index (FVI) for evaluating SRF species. Biomass from the 4 year rotation harvest was used as feedstock to fuel a downdraft air gasifier rated 35 kW (electric). Feedstock gasification processes, gas quantity and quality were correlated with the biomass properties to define the characteristics of a good fuelwood species for gasification purposes. The Kenyan studies highlighted constraints in the energy sector and identified opportunities for new bioenergy technologies. Small scale biomass gasification systems showed potential but suitable sites were restricted to sawmills where processing residues could be used as gasifier feedstock. Field trials of SRF systems were recommended to evaluate tree species over different silvicultural treatments, and to intensify biomass production. A demonstration plant at one of the bigger sawmills was recommended to stimulate interest among investors. Species yields of the trial plantings in New Zealand in the 12 species assessed ranged from 6 ODt/ha/y for Alnus glutinosa to 73 ODt/ha/y for Eucalyptus globulus at 5 year rotations. A stocking density trial of E.saligna showed that 3,500 stems/ha mana…
abstract: Downdraft gasification of short rotation forestry (SRF) biomass was investigated to identify opportunities for small scale biomass-electricity systems. Case studies were conducted in Kenya to identify these opportunities by (i) defining the energy demand and supply structure to identify markets; (ii) evaluating the biomass resources available; and (iii) identifying the availability of other facilities required for such a system. At the same time, the yield potential of 12 SRF species, planted in Palmerston North, New Zealand in small plots at 3470 stems/ha and harvested after 2, 3, 4 and 5 years was evaluated. Samples were collected from each species to determine their energy properties. Data on tree growth, yield, and biomass properties were used to develop two multi-objective indices - the relative yield index (RYI) and the fuelwood value index (FVI) for evaluating SRF species. Biomass from the 4 year rotation harvest was used as feedstock to fuel a downdraft air gasifier rated 35 kW (electric). Feedstock gasification processes, gas quantity and quality were correlated with the biomass properties to define the characteristics of a good fuelwood species for gasification purposes. The Kenyan studies highlighted constraints in the energy sector and identified opportunities for new bioenergy technologies. Small scale biomass gasification systems showed potential but suitable sites were restricted to sawmills where processing residues could be used as gasifier feedstock. Field trials of SRF systems were recommended to evaluate tree species over different silvicultural treatments, and to intensify biomass production. A demonstration plant at one of the bigger sawmills was recommended to stimulate interest among investors. Species yields of the trial plantings in New Zealand in the 12 species assessed ranged from 6 ODt/ha/y for Alnus glutinosa to 73 ODt/ha/y for Eucalyptus globulus at 5 year rotations. A stocking density trial of E.saligna showed that 3,500 stems/ha mana…
author: Senelwa, Kingiri A.
keywords: Wood fuel, Energy technology, Kenya
date published: 1997
date modified: 2026-07-27T20:17:14Z
provider: Massey University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Massey University