Generating and Determining the Products of Premixed Combustion of Solid Materials in a Microscale Fire Calorimeter

A method of generating soot and other products of incomplete combustion, the method comprising the steps of:

• thermally decomposing a milligram-sized sample of a solid material at a constant rate of temperature rise to generate fuel gases in a test chamber of a microscale fire calorimeter;
• transporting the generated fuel gases from the test chamber to a mixing portion of a ultra-high temperature combustion furnace of the microscale fire calorimeter using an inert carrier gas having an inert carrier gas mass flow rate, the ultra-high temperature combustion furnace having a temperature, Tc;
• introducing oxygen having an oxygen mass flow rate into the mixing portion of the ultra-high temperature combustion furnace;
• in order to create a premixed volume of the generated fuel gases and oxygen, controlling the inert carrier gas mass flow rate and the oxygen mass gas flow rate to the ultra-high temperature combustion furnace by using a predetermined oxygen-to-fuel mass ratio, r0(T), so that the oxygen-to-fuel mass ratio, r(T), is a multiplier of r0(T), wherein the predetermined oxygen-to-fuel mass ratio, r0(T), is the stoichiometric oxygen-to-fuel mass ratio for complete combustion of the solid material at a temperature, T;
• and,
• combusting the premixed volume of the generated fuel gases and oxygen in the ultra-high temperature combustion furnace to create an effluent, the effluent including soot and other products of incomplete combustion of the solid.

A microscale fire calorimeter system for determining the combustion products of solid materials across a range of flame temperatures, comprising:

• a pyrolyzer including a heating member for thermally decomposing a milligram-sized sample of a solid material under anaerobic conditions to generate fuel gases, the pyrolyzer including an inlet for receiving a purge gas and a mass flow controller for controlling the mass flow rate of the purge gas through the purge gas inlet into the pyrolyzer;
• a mixing portion for generating a premixed volume of the generated fuel gases and oxygen, the mixing portion including an inlet for receiving oxygen and a mass flow controller for controlling the volumetric flow rate of the oxygen through the oxygen inlet into the mixing portion;
• and,
• an ultra-high temperature combustion furnace including a heating member for combusting the premixed volume of the generated fuel gases and oxygen in the range of flame temperatures in order to produce gaseous and solid combustion products;
• wherein the purge gas mass flow controller and the oxygen mass flow controller are controlled to create a constant total volumetric flow rate of oxygen and inert purge gas and are further controlled so that the oxygen-to-fuel mass ratio, r(T), in the ultra-high temperature combustion furnace at each temperature, T, is a multiplier of r0(T), wherein r0(T) is the stoichiometric oxygen-to-fuel mass ratio for complete combustion of the solid material at the temperature, T.