Use this URL to cite or link to this record in EThOS:
Title: Self-heating ignition of natural reactive porous media
Author: Restuccia, Francesco
ISNI:       0000 0004 7229 145X
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2018
Availability of Full Text:
Access from EThOS:
Access from Institution:
Self-heating is the tendency of certain porous solid fuels to undergo spontaneous exothermic reactions in oxidative atmospheres at low temperatures. Self-heating can cause accidental ignition of reactive porous media leading to wildfires, ecosystem damage, property damage, loss of industrial facilities and even loss of life. Traditional self-heating ignition literature studies have been dominated by coal. However, there are many other materials prone to self-heating ignition like biomass and other natural occurring materials. Using oven basket experiments coupled with the Frank-Kamenetskii theory of ignition, this thesis aims at quantifying self-heating ignition risk and properties, and quantifying the chemical kinetics and thermal properties of natural fuels such as shale, carbon-rich soils such as peatlands, and biochars produced from wheat, rice husks, and softwood upscaling the results to real systems. This method requires extensive laboratory time, but gives the most accurate self-heating results. The thesis focuses on the effect of three main physical parameters: carbon content, inorganic content, and particle size of the fuel. I show that shale rock can self-heat in normal ambient conditions. Using soil biomass samples with inorganic content between 3% and 86% of dry weight, I quantify the effect of inorganic content on self-heating ignition, and show that self-heating can initiate wildfires in some soil types and conditions. I quantify the reactivity of softwood biochar produced as a function of the pyrolysis reactor temperature. I show that the reactivity of softwood is not a monotonic function of pyrolysis reactor temperature. I present an experimental comparison of wheat, rice husk, and softwood biomass and biochar, quantifying the differences between different feedstock sources and what effect this has on the biochar's relative fire risk. Finally, I quantify the effect of particle size diameter on self-heating ignition for wheat, showing that the critical temperature for self-heating ignition decreases with particle size.
Supervisor: Rein, Guillermo ; Navarro-Martinez, Salvador Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral