I am working on experimental investigation of Coal Gasification Reaction on Pressurized Thermogravimetric Analyzer (PTGA). I am getting the WAIT GAIN instead of wait loss at high pressure with dynamic heating system. I want to ask what is the reason and how i can rectify this issue?
If you have residual oxygen in the system, you may be oxidizing sulfur-containing species to sulfates. Similarly, many suboxide inorganic species may oxidize and gain mass if there is some residual oxygen. It is common to have residual oxygen. Unless you have measured it with a device with a low detection limit (e.g. mass spec), you cannot be sure there is none.
Hello Imran Nazir Unar,
I think, there must be something wrong with the equipment. Looking at the plots I assume, you have a constant ramp to something around 950 °C and holding the temperature there.
First, there sould not be a weight loss higher than 100 % and even if it was only 100 % there obviously could be no gain in weight, because there was no coal left. Normally I should expect a residue of ash something over 5 % of initial weight and even if there would be a gain in weight of the ash, it hardly would exceed 10 % of initial weight.
Second, there should be a pyrolysis peak, perhaps a drying peak, drawing the first derivate. Well, though I don't have the derivate, there is definitely no pyrolysis peak. The rapid decrease at 10 atm is far below 100 °C, so it cannot be water, what should it be? The signal you obtained is not the weight of the sample, never.
Check your wires to the data logger in first place, I doubt the signal comes from the balance.
Good luck, Jörg Ho
nice day for all,
In addition to the idea of Larry L. Baxter, I think that your measurment system itself needs some corrections such as preleminary calibration. Indeed, the mass loss percentage (not the conversion as you write on the y axis) musn't exceed 100%. Also, the increase after reaching a high temperature '>800°C) has not a physical meaning only if you have a condensation phase of volatile compounds and ash. Previously, when working on torrefaction of biomass using ATD-DSC device, I have found similar results and one discovered that it was a problem in relation with the apparatus. what I advice you is to use an etalon matrial and to find the predicted results after adjusting your measurment system.
Hello dear sir, Have you found the exact reason for this question? Why mass increasing after 800 C?
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