Online detection of ethanol in the exhaust air stream of the fermenter in real time without sampling and analysis. The device is also applicable for other combustible organic materials, for instance the detection of methanol in pichia yeast fermentation.
The probe, a tube covered with a silicone diaphragm, is placed inside the exhaust gas pipe of the fermenter. Pressure adjusted instrument air is conducted through the probe and enriched with ethanol diffusing through the diaphragm.
For gas analysis a semiconductor sensor element is used, which is located in the switchboard and connected with the ethanol enriched air stream. Depending on the transmitted signal, the corresponding ethanol concentration in the fermentation mash is calculated. Signal linearization is carried out by use of pre-installed calibration data.
Process values such as the calculated ethanol concentration, temperature and sensor resistance are shown on the LCD display of the switchboard. For the purpose of process control, the linearized signal is converted to a standard current signal and two limit relay contacts which can be used as input signal for any process control system or for visualization and/or documentation.
The GS2/7 gas analyzer system is applicable for any type of fermenter and any type of control system. It is easily installed and integrated with existing equipment.
The system consists of a probe which is placed in the exhaust pipe of the fermenter and connected to a switchboard by a flexible tube.
The switchboard is designed for field installation in the vicinity (less than 5 meter) of the fermenter, preferable on a wall to be free of vibrations. Power-supply and instrument air must be available, as well as connections to the PCS for further use of signal.
To mount the probe, a ½" welding socket has to be installed in the exhaust gas pipe. The fittings are included in the delivery.
| Weight of switchboard | 10 kg |
| Dimensions of switchboard HxWxD | 400 x 300 x 200 mm |
| Power supply | 230 V / 50 Hz |
| Instrument air supply (4 bar g) | 50 Ndm³/h |
| Power consumption | approx. 100 W |
| Operating Range | selectable 0 - 0.2 and 0 - 1 vol% ethanol |
| Accuracy | ≤0.01 vol% ethanol |
| Reproducibility | ±0.05 vol% ethanol |
| Response time | approx. 60 seconds |
| Operating temperature range | 0 - 45 °C |
|
Output |
4 - 20mA (analogue) 2 x relay contact (binary) |
Monitoring the ethanol formation in aerobic yeast fermentations is used to observe its progress for the optimization of process efficiency.
The GS2/7 multifunction unit can act as an independent flow controller for molasses feed, or provide the input signal for an external flow controller (remote setpoint operation).
This gas analyzer system was specifically developed by Vogelbusch for bioprocess applications.
It is made from standard industrial components to ensure optimum availability with minimum maintenance. The following design features are part of the scope of supply:
The sensors used are extremely stable, with a design service life of several months. Recalibration to compensate raw material effects can easily be done by client on site.
In the event of sensor replacement, pre-calibrated sensors can be obtained from Vogelbusch or calibration can be carried out by client on site.
Similar developments are available from Vogelbusch for application in vinegar and alcohol fermentations:
» GS2E Gas Analyzer for vinegar fermentations
» IR-SD2/2 Gas Analyzer for alcohol fermentations