Review of the Design and Operation Criteria of a DC Submerged Arc Discharge Carbon Nanostructure Synthesis Installation
Table 5
Electronic DAQ and control system requirements, operation parameters selection.
Measurements
Parameters
Observations
Correlated
Current
Optimal current density 106–177 A · cm−2 (for typical anode r = 0.3 cm, I in the range of 30–50 A). Source current range 0–70 A. The stabilization system must guarantee arc current fluctuations ≤3%
Voltage
Source voltage range 0–70 V. The stabilization system must guarantee arc voltage fluctuations ≤5%
Stepper motor pulses
The use of a step motor gave the possibility to know the anode displacement at any moment
Light emission
Photodiode placed inside the reactor, in a plane perpendicular to the axis of the electrodes that intercepts it in the gap between them and coupled with optical fiber to the measurement system
Sound emission
Contactless diagnosis. Detection of vibrations (electrode holders, electrodes, micropositioning system), bubbling, chemical reactions, and mechanical failures. It is recommended to use electret microphones because they are simple, robust, and cheap. Its frequency response is flat. The main SADW processes generate sounds with frequencies lower than 20 kHz. They are placed inside the reactor
