# Nonthermal Plasma Multi-Reactor Scale-Up Using Pulse Capacitive Power Supplies
###### Abstract  
The scale up of nonthermal plasma (NTP) reactors requires the simultaneous operation in parallel of a large number of units supplied from the same power supply. The present paper aims to demonstrate the feasibility of parallel operation of multiple mini-NTP reactors. In order to demonstrate the parallel operation of a large number of NTP reactors, three different types of power supplies are considered. In addition to the most simple and common solution, which involves the use of individual, independent power supply for each reactor (an ignition coil driven by a pulse generator), two other configurations of supplies (capacitive AC and capacitive DC), simpler and less expensive, are tested. The capacitive pulsed power supplies allow the generation of HV pulses by an AC power supply (usually an AC transformer), as well as by a DC power supply using an R-C circuit. For the DC resistive-capacitive configuration, the frequency can be adjusted. For all configurations, the power of the discharge can be modified by changing the value of capacitors or resistors. The feasibility of the proposed systems was demonstrated by assessing the concentration of hydrogen peroxide induced in water after plasma treatment. The obtained results reveal that the proposed capacitive AC and DC power supplies allow a large number of plasma reactors to operate in parallel independently. n onthermal plasma; hydrogen peroxide; multi-reactor system; capacitive pulsed power supply +
Footnote †: journal: Applied  
reactive species and their reaction pathways are essential to optimize the design of NTP reactors for real applications. Most nonthermal plasma applications, such as the depollution of the water and air, the production of activated water (PAW) for applications in agriculture, and surface disinfection, require the adaptation of power supplies for the production of plasma to specific conditions of each application [9; 10]. The components of saturated and unsaturated hydrocarbons are highly reactive to radical species and ozone, and they are easily decomposed in the NTP reactors [11; 12; 13]. In order to increase the degradation of the organic pollutant, an alternative reactor configuration has been shown to be much more effective than the treatment of water in a batch. In this alternative configuration, a small quantity of liquid is sprayed directly into the plasma generated by a pulsed high-voltage discharge of an NTP reactor with confined plasma. It was demonstrated that the treatment of polluted water or PAW production in pulsed NTP mini-reactors with spray (up to 20 mL/min water flow rate) is up to 10 times more effective than the treatment or PAW production in batch reactors [14; 15]. The technological simplicity and ability to operate at atmospheric pressure and temperature [16] make NTP reactors suitable for a wide variety of industrial applications. Another challenge of using cold plasma is to increase the volume of plasma-activated water (PAW), especially for applications in agriculture where a high volume of water is required. The nonthermal plasma-activated water (PAW) produced by pulsed NTP spray technology [17; 18; 19; 20] has a notable effect on plant growth and pest elimination (bio-disinfection). It was demonstrated that PAW reduces the period of plant growth, increases the biomass, and provides the disinfection of plant leaves, and it is also effective as a bio fertilizer. One problem that limits the use of NTP electrochemical reactors to treat large amounts of water is the difficulty to upscale NTP systems. The difficulty resides in the parallel operation of a large number of NTP reactors powered by the same power supply, which requires the parallel operation of several electric discharges. The design, development, and analysis of the possibility of upscaling the NTP chemical reactors for industrial application are of critical importance for the development of NTP technologies [21].