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Predicting storage vessel geometry requirements for discharge of extreme shape materials

Predicting storage vessel geometry requirements for discharge of extreme shape materials

Owonikoko, Aminu (2012) Predicting storage vessel geometry requirements for discharge of extreme shape materials. MPhil thesis, University of Greenwich.

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Abstract

The rush to sustainable/renewable energy to mitigate the global warming or green-house gas emissions is global and is increasing everyday especially on bioenergy/biofuels. Clean Development Mechanism was developed in the Kyoto Protocol to ensure the mitigation of global warming is achieved in developing countries and developed (industrialised) countries. To achieve these important goals, the right equipment to handle and process biomass materials is required in order to produce the carbon-neutral energy (renewable energy).

In order to specify the right equipment and to evaluate the existing process technologies which are not meeting the expectations of the industry, the bulk mechanical/flow properties that make up the feedstock (raw materials) used to generate the biofuels needs to be characterised. The particles that make up biofuels materials (i.e. biomass and waste materials) are extreme/irregular in shape. They are classified as extreme shape materials (ESM) “Class 3” by The Wolfson Centre for Bulk Solids Handling Technology based on their many years of research into these materials. They are elastic, fibrous, flaky, and stringy in nature and have a tendency to nest or interlace (Bradley and Farnish, 2004; FEM 2581/2582, 1991; Mattsson, J.E 1990; Bell T.A. 1999; Johanson J.R., 1989; McGee Eddie, 2009). Examples of ESM are woodchips, miscanthus (elephant grass), shredded paper, municipal solid wastes, industrial and commercial wastes, corn stover, straw, lawn grass, chicken/poultry litter, etc.

Most conversion (process) technologies like pyrolysis, gasification, combustion, trans-esterification, anaerobic digestion, fermentation under-perform because biomass and waste materials are resistant to flow in the feeder (silo/hopper) which supplies feedstock into the conversion chambers. Research outputs have shown that the resistance to flow of extreme shape biomass is due to their high aspect ratio, inherent low bulk density, inherent high moisture content and their stress phobic nature (Owonikoko et al, 2010; Johanson J.R., 1989; Bundalli N., 1986; The Roger et al, 1994; Bradley and Farnish, 2004) which contributes significantly to their nesting/entanglement behaviour. In order to de-nest class 3 materials (Extreme Shape Materials), the flow (mechanical) properties of the materials have been researched. The techniques developed and adopted have provided a framework to produce a design procedure to determine the hopper geometry, wall angle, outlet size and internal finish required to ensure a given biomass and waste materials discharge reliably from the vessel.

Item Type: Thesis (MPhil)
Uncontrolled Keywords: sustainable energy, biomass materials, bulk solids handling technology, process engineering,
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TP Chemical technology
Pre-2014 Departments: School of Engineering
School of Engineering > Department of Engineering Systems
Last Modified: 14 Oct 2016 09:26
Selected for GREAT 2016: None
Selected for GREAT 2017: None
Selected for GREAT 2018: None
URI: http://gala.gre.ac.uk/id/eprint/10798

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