A User-Friendly Set up for Undergraduate Research: Combining
Thermogravimetric Analysis with Micro Gas Chromatography
12Edwin David , Dr. Amanda Simson
1Department of Chemistry and Chemical Engineering, University of New Haven
2Department of Chemical Engineering, The Cooper Union

Introduction

TPR Data

Gasification Data

Investigated coupling TGA/DSC (Thermal Gravimetric Analyzer withDifferential Scanning Calorimetry) with a portable Micro-GC (GasChromatography) to:• perform common catalyst characterization tests (instead of achemisorption unit)• act as an easy reactor system for gas/solid reactions
In small research labs, this system allows for more versatility (since aTGA and Micro-GC can be used for multiple purposes).

Temperature Programmed Reduction (TPR) shows reduction behavior of anoxidized catalytic metal providing important information about the activemetal.

Temperature programmed Dry Gasification, using CO2 (the reverse Boudouardreaction) was investigated on various biochars.
CO2 + C  2CO

Oxidized Catalytic Material + H2  H2O + <H2 + Reduced Catalytic MaterialGas analysis was able toconfirm that we weremeasuring weight loss due todry gasification on the TGA.

Instrumentation
Thermal Gravimetric Analyzer (TA Q600)• Offers the possibility of simultaneous
measurement of weight change and true
differential heat flow (differentialscanning calorimetry (DSC)• Can test to 1,500˚C
INFICON Micro GC Fusion Gas Analyzer• Portable gas chromatography withextremely short analysis time
• Provides ppm to % level detection• User friendly front panel display andembedded browser-based software• Configured with a 10 m Molecular Sieve
5A (Argon) and 8 m Q-Bond Plot columns(Helium)

Figure 8: Derivative weight loss
(measured by TGA) and concentration ofcarbon monoxide (measured by microGC) with ramp rate of 5°C/min in 100mL/min 5% CO2/N2.
Figure 5: Water produced and hydrogen consumed during Temperature Programmed Reduction
tests on a 40 mg 10% Copper catalyst with 4% H2/N2 at 100 mL/min total flow.
Figure 1: Thermogravimmetric Analysis /Differential Scanning Calorimetry

TPR data demonstrates:• Micro-GC data confirmed what was measured on the TGA, and was inclose agreement• Micro GC measured both hydrogen depletion and water production, andcould be optimized for either signal (water signal optimized in Figure 5).

Conclusions + Recommendations

TPO Data

Some primary benefits of the set-up:

Temperature Programmed Oxidation (TPO) tests are commonly used tomeasure the amount or type of carbonaceous species on a catalytic surface:
Figure 2: Micro Gas Chromatography

Experimental Design

Catalytic material with carbon + O2  CO2 + CO + <O2 + carbon-free material
TPO tests can also measure oxidation of a metal, combustion behavior of ahydrocarbon sample, or to measure relative C/H ratios of a biomass sample.
CxHy + O2  xCO2 + yH2O

This set up was used to test thefollowing solid/gas reactions:

Biochar Sample

 TPR on 10% Cu/Al2O3
 TPO on biochars (CxHy)

Figure 6: Gases produced (measured by micro-GC)
and %weight loss (measured by TGA) during a
Temperature Programmed Oxidation of a 30 mg
biochar sample (ground acorn nutmeat). Ramp rate
= 5°C/min with 100% air at 100 mL/min total flow.

 Dry Gasification (CO2) of biochars
Biochars were produced from Acorns
or Oakheart by pyrolysis in Argon at500C.

Figure 4: TGA/DSC connected to the Micro
GC gas analyzer

Oakheart
Acornhat
Acornshell
NutmeatAcornshell• Versatility: both instruments were used on other projects in the lab, andthe INFICON Micro-GC was easily portable allowing for the two
instruments to easily have multiple uses.
• Ease of use: undergraduate researchers were able to quickly learn andgrasp both techniques, and easily analyze data from both instruments.
Both instruments were robust enough for independent use. Embedded
Micro-GC software allowed for quick learning for students.
• Sample rates: the Micro-GC was able to complete runs quickly (on order of
1 sample per minute) so samples could be synced between instruments.

CO2 and H2O concentrations
could be integrated todetermine the C/H ratio of
biochar samples, which
could not be done with atypical chemisorption unit.

Figure 3: Schematic of the set up: TGA connected to the Micro GC

Benefits for biomass research A TGA without gas analysis could analyze
only the temperature that pyrolysis occurs, or the ash content. However,we were able to quantify gas species (including H2 - difficult to measurewith mass spectrometry). Thus we were able to measure C/H ratios of oursamples and confirm gasification products above.

C:H MolRatio
3.4
3.7
2.4
4.0
2.2

Figure 7: C/H ratio of several biochar
species calculated from TPO

In the future we would:• Use a heated transfer line and reduce residence time in transfer line.
• Maximize TGA sample cup sizes to increase signal size.

Acknowledgements
The authors would like to thank INFICON for allowing use of the instrument
to conduct these studies, and to TA Instruments for useful discussions inoptimizing the TGA/GC interface. Additionally, Micah Fertig, Michele Berman,and Morgan Nivison for their help with set-up and experimentation.