AutoChem II - TCD Calibration

Summary

This video demonstrates how to perform a TCD calibration on the Micromeritics AutoChem II Automated Catalyst Characterization System. It covers the steps for calibrating the thermal conductivity detector (TCD) signals, including setting up the system with various gases, flow rates, and sample conditions. The calibration process is crucial for ensuring accurate data during temperature-programmed analyses like TPR, TPD, and TPO. Additionally, the video provides instructions on creating calibration curves, applying them before or after analysis, and managing files in the MicroActive Software for efficient data analysis.

Takeaways

• 😀 Always consult the operator’s manual for detailed information when performing TCD calibration on the Micromeritics AutoChem II.
• 😀 TCD calibration on the AutoChem II is important for accurate gas consumption or desorption measurements in temperature programmed analyses.
• 😀 Calibration is not necessary if the quantity of gas consumed or desorbed is not required for the analysis.
• 😀 Perform a TCD calibration whenever using a new gas cylinder or changing the flow rate of the same gas cylinder.
• 😀 If you change the flow rate, a new calibration is required (e.g., from 50cc/min to 30cc/min).
• 😀 TPR, TPO, and TPD analyses require different gas setups for calibration, such as hydrogen-argon for TPR or helium-ammonia for TPD.
• 😀 The calibration process starts by loading an empty sample tube and creating a new sample file in the MicroActive Software.
• 😀 Enter relevant details in the software, such as active gas percentage, gas blend, flow rate, and date, for accurate calibration.
• 😀 Once the calibration begins, the analyzer will gradually decrease the analysis gas in 10% increments.
• 😀 After calibration, create a calibration curve and select the appropriate calibration curve before or after the analysis depending on when calibration is performed.
• 😀 You can apply the calibration either before starting an analysis or by selecting the calibration curve after an analysis in the Peak Editor.

Q & A

What is the purpose of performing a TCD calibration on the Micromeritics AutoChem II?

The TCD calibration ensures that the signals from the thermal conductivity detector are accurate, which is necessary for determining the quantity of gas consumed or desorbed during temperature-programmed analyses.

Is a TCD calibration required in every application?

No, a calibration is not necessary in applications where the quantity of gas consumed or desorbed is not required. It is only needed when that information is essential for the analysis.

When should a TCD calibration be performed?

A TCD calibration should be performed when using a new gas cylinder or if the flow rate is changed from the previous calibration. For example, when changing the flow rate during a TPR analysis, a new calibration should be done.

What gases are typically used in TPR, TPO, and TPD analyses?

In TPR (Temperature Programmed Reduction), hydrogen blended in argon is used. In TPO (Temperature Programmed Oxidation), oxygen blended in helium is used. In TPD (Temperature Programmed Desorption), ammonia blended in helium is typically used.

What should be done before starting the calibration process?

Before starting the calibration, load an empty sample tube on the sample port, close the furnace, and then create a new sample file in the MicroActive software.

How do you set up the calibration in the MicroActive Software?

In the MicroActive software, you need to go to 'Analysis Conditions', select 'Insert > Gas Calibration', and then enter details like active gas percentage, gas blend, flow rate, and the date. Make sure to select the correct carrier and loop gases.

What is the importance of matching the carrier gas during calibration?

It is important to match the carrier gas of the calibration to the carrier gas used in the actual experiment to ensure accurate calibration and data results.

How do you apply the calibration curve to an analysis?

The calibration curve can be applied before or after the analysis. If the calibration is done before the analysis, select the appropriate calibration curve when starting the analysis. If done after, go to the Peak Editor, click on 'calibration', and select the relevant calibration curve.

What is the significance of selecting a first or second-degree fit for the calibration curve?

The choice between a first or second-degree fit depends on which one provides a better goodness of fit for the calibration data. The more accurate the fit, the more reliable the calibration results will be.

What happens during the gas calibration process?

During the gas calibration, the analyzer decreases the proportion of the analysis gas in 10% increments, starting at 100% and ending at 0%. This process helps to create a reliable calibration curve.