Device and method for calorimetrically measuring sorption processes
The aim of the invention is to provide a commercially usable and inexpensive device and method with which a sorption enthalpy can be measured in a simple manner. This is achieved by a device for calorimetrically measuring sorption processes, comprising a sorption cell for receiving a sample, the sorption cell having a volume for filling with a sorption gas, and comprising a reference cell likewise for filing with the sorption gas. A measurement gas volume is arranged around the sorption cell for receiving a reference gas, and the reference cell is surrounded by a reference gas volume, which is likewise provided for receiving the reference gas. A gas connection is provided between the sorption cell and the reference cell in order to conduct sorption gas into the sorption cell and the reference cell such that a sorption reaction occurs with the sample in the sorption cell. Furthermore, a device is provided for measuring pressure differences between the measurement gas volume and the reference gas volume in order to carry out a calorimetric measurement of the sorption process on the sample in the sorption cell on the basis of a volume change of the reference gas in the measurement gas volume.
1. A device for calorimetrically measuring a sorption reactions, comprising:
a sorption cell for receiving a sample and having a volume to receive a sorption gas;
a reference cell having a volume to receive the sorption gas;
a measurement gas container surrounding the sorption cell and having a volume for receiving a reference gas;
a reference gas container surrounding the reference cell and having a volume for receiving the reference gas;
a gas connection disposed between the sorption cell and the reference cell and fluidically coupling the volumes of the sorption cell and the reference cell;
a differential pressure sensor coupled to the measurement gas container and the reference gas container to determine a pressure difference there between that is proportional to heat released in a sorption reaction between the sorption gas and the sample; and
a control unit in communication with the sorption cell, the reference cell and the differential pressure sensor, the control unit configured for determination of the heat released in the sorption reaction based on a pressure difference measured by the differential pressure sensor.
2. The device according to claim 1 , wherein
a first heating element is disposed inside the sorption cell and a second heating element is disposed inside the reference cell.
3. The device according to claim 2 , wherein
the first and second heating elements are regulated separately by means of the control unit for both the sorption cell and the reference cell.
4. The device according to claim 2 , wherein
the first heating element is used to record the temperature of the inside of the sorption cell and the second heating element is used to record the temperature of the inside of the reference cell.
5. The device according to claim 2 , wherein
each of the first and second heating elements comprises an electrical resistor element.
6. The device according to claim 3 , wherein
the control unit performs a calibration, which takes place by means of an alternating or simultaneous short-term, regulated heating of the sorption cell and/or the reference cell.
7. The device according to claim 1 , wherein
the reference cell has a same geometry as the sorption cell.
8. The device according to claim 1 , wherein
an intake device is provided for filling of the sorption cell and/or the reference cell.
9. The device according to claim 1 , wherein
the reference gas container has a same geometry as the measurement gas container.
10. The device according to claim 1 , wherein
a line for connecting the inside of the measurement gas container and the reference gas container is provided for equalizing the pressure.