The thermogravimetric analysis aims to give % mass change with increasing temperature over the time period while proximate analysis gives moisture, ash, volatile matter and fixed carbon contents by measuring the % weight change in biomass at a known temperature in particular time.
So, is it possible to obtain the data for proximate properties with TGA graphs only?
Hi. For moisture you can: If you are sure about your thermostability till 100 degrees celcius under nitrogen environment, I suggest you run two step TGA (1. ramp up to 100 degrees C in 10 minutes, 2. isothermal step for 30 minutes).
The difference in the first and the last weight should give you moisture content in your sample.
Moisture content is one thing, I'm looking for other components (Moisture, Volatile and Ash content) from TGA graph.
Is there any methodology available?
Tankut Türel
I am not sure about volatility. To the best of my knowledge, we cannot do volatility with TGA. However, ash content is doable. You need to run TGA till your sample remains constant weight (I suggest 800C, or 1000C). That constant weight will be your ash content.
Yes it's possible to establish proximate parameters of biomass through TGA. For the analysis, design the program in dynamic and isothermal steps for Nitrogen and Air medium.
1. Run the experiment from ambient to 100 degrees at certain heating rate ( say 20 degree/min) and hold there for atleast 20 minutes. The mass percent loss gives moisture content.
2. Run the experiment from 100 to 900 degrees in Nitrogen environment and hold there for 20 minutes (for the release of volatiles). This mass difference gives volatile content.
3. After volatile release, burn the sample in air at 900 degrees. This will give the ash content.
4. The fixed carbon can be calculated by difference method (100% - % moisture - % volatiles - % ash).
Through the TGA graph, you can't extract the exact percentage of MC, VM, FC, and Ash. Bcz TGA in air and inert environment have different degradation behavior.
Article Application of Thermogravimetric Analysis for the Proximate ...
I think this work by Cantrell et al. will shed some light on this topic.
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