High-Efficiency Carbon Dioxide Reduction Using Nonthermal Plasma Desorption

Abstract

We present a highly efficient carbon dioxide (CO2) reduction treatment technique using an adsorbent and nonthermal plasma flow at the laboratory scale. The plasma reactor consists of twelve surface discharge elements, which are energized by a 10-kHz bipolar pulsed high-voltage power supply. As an adsorbent, the molecular sieve zeolite 13X is used, and it is placed downstream of the plasma reactor. In the physical adsorption process, approximately 10% CO2 gas with flow rate 10 L/min is prepared by 99.5% CO2/N2 cylinder and a nitrogen cylinder. It is then introduced into the flow channel, and CO2 is adsorbed by the adsorbent. After the adsorption process, the circulation flow channel is set and the N2 plasma flow is generated with a blower. Consequently, CO2 adsorbed by the adsorbent is desorbed with higher concentration (currently ∼20%) and reduced to CO with high efficiency. The generated CO can be reused as a fuel. We evaluate the experimental results by calculating the conversion efficiency of CO2 to CO and the energy efficiency of the plasma. When the number of repetitions of experiments is 5, a maximum CO concentration of 5% and a maximum CO2 concentration of 20% are reached. The energy efficiency associated with the conversion of desorbed CO2 to CO reaches 14% with the plasma power of 300 W. Discussions are carried out by comparing the value with those obtained in other studies on the plasma reduction of CO2.