Macro Thermogravimetric Analyzer, TGA (Dryer, Pyrolyser)

Thin-layer Macro Thermogravimetric Analyzer 

A thin-layer thermogravimetric analyzer is designed and constructed to measure the mass of samples continuously during a thermal treatment test. Figure 1 shows the schematic picture of the constructed apparatus. The equipment consists of three sets of component parts: dryer/pyrolyzer section, instantaneous mass-measuring unit (Sartorius balance, Quintix 412-1S) and heating/controls system. The heating system includes an in-line preheater and an infrared heater. Figure 2 shows the in-line preheater, infrared heater, weight measuring system and the temperature controller panel. 

The chamber is a rectangular box made of stainless steel with a cross section of 200 mm x 300 mm and a length of 400 mm. The sample holder (40 mm x 60 mm) inside the chamber rests on a stainless-steel mesh platform (50 mm x 70 mm). The platform has a fixed connection to a titanium rod (300 mm length). The rod lower-end rests on a digital balance located underneath the chamber. A small access door (50 mm x 70 mm) installed on the chamber front-wall is used to place or remove the sample from the chamber. 

An infrared heater with a fused quartz surface (Omega, QC-061040-T) installed on top side of the vessel heats up the atmosphere inside the chamber to the targeted temperatures of 50-600 °C. The balance records the mass of the samples continuously. A pre-set continuous carrying gas passes through an in-line electrical pre-heater (Omega, AHP-7561). A K-type thermocouple records the temperature of the point of 10-mm distance from the sample holder and sent the signal to the temperature controller. The temperature controller keeps the temperature of the monitoring point at the temperature set point. The hot carrying gases passes over the particles, transfers the heat to the particles and carries the released moisture/volatiles out of the dryer. The balance transmits the sample mass continuously to a computer receiver, recording the data in an excel file. 

The detail of design and application of the apparatus is published in the following document. 

Rezaei H, Physical and Thermal Characterization of Ground Wood Chip and Ground Wood Pellet Particles, PhD Dissertation, University of British Columbia, 2017 

Figure 1 – Schematic picture of the thin layer dryer/pyrolyzer (different parts are not in the same scale). 

Figure 2 – Picture of macro TGA equipment, showing preheater, infrared heater, weight-measuring system and temperature controller panel.