Plasma‐Assisted Reforming of Methane

Abstract

Methane (CH4) is inexpensive, high in heating value, relatively low in carbon footprint compared to coal, and thus a promising energy resource. However, the locations of natural gas production sites are typically far from industrial areas. Therefore, transportation is needed, which could considerably increase the sale price of natural gas. Thus, the development of distributed, clean, affordable processes for the efficient conversion of CH4 has increasingly attracted people's attention. Among them are plasma technology with the advantages of mild operating conditions, low space need, and quick generation of energetic and chemically active species, which allows the reaction to occur far from the thermodynamic equilibrium and at a reasonable cost. Significant progress in plasma‐assisted reforming of methane (PARM) is achieved and reviewed in this paper from the perspectives of reactor development, thermal and nonthermal PARM routes, and catalysis. The factors affecting the conversion of reactants and the selectivity of products are studied. The findings from the past works and the insight into the existing challenges in this work should benefit the further development of reactors, high‐performance catalysts, and PARM routes.

One-Step Synthesis of Ammonia Directly from Wet Air/N2 by Plasma Combined with a γ-Al2O3 Catalyst

“…The order of the area of the Lissajous diagram was Al 2 O 3 + wet N 2 (14.08) > Al 2 O 3 + wet air (12.48) > only wet N 2 (7.31) > only wet air (5.11), which shows that packing the catalyst between the discharge gaps can significantly increase the P output . The catalyst present between the discharge gaps can increase charge deposition and the electric field strength, thereby increasing the active species’ adsorption rate and contact time and ultimately enhancing the possibility of collisions and reactions . This is because packing the catalyst particles increases the dielectric constant of the materials, thereby making the polarization at the contact point of the catalyst particles more effective. − …”

“…The physical and chemical properties of the catalyst may change after discharge, , which may be one of the reasons for the decrease in catalyst activity. To investigate the reason for the decrease in γ-Al 2 O 3 catalyst activity and the effect of discharge on the γ-Al 2 O 3 catalysts used in this study, γ-Al 2 O 3 was collected after they were discharged at an SEI of 11.68 J mL –1 for 100 min.…”

“…The catalyst present between the discharge gaps can increase charge deposition and the electric field strength, thereby increasing the active species' adsorption rate and contact time and ultimately enhancing the possibility of collisions and reactions. 12 This is because packing the catalyst particles increases the dielectric constant of the materials, thereby making the polarization at the contact point of the catalyst particles more effective. 27−31 In previous reports, 25,32 the SEI was found to affect the experimental results significantly.…”

“…Plasma technology allows the ammonia synthesis reaction to be carried out far from the thermodynamic equilibrium and at a reasonable cost. , Irving Langmuir first introduced the concept of “plasma” in 1928, which is a special type of conducting fluid (ionized gas or sometimes liquid). , A typical characteristic of plasma is that the system is electrically neutral, partially or completely ionized. Broadly, plasma is generally defined as a partially or fully ionized gas . The use of nonthermal plasma technology to synthesize NH 3 has been studied extensively.…”

“…Broadly, plasma is generally defined as a partially or fully ionized gas. 12 The use of nonthermal plasma technology to synthesize NH 3 has been studied extensively. Compared with traditional synthetic NH 3 technology, synthesizing NH 3 with plasma technology has the advantages of mild reaction conditions and no greenhouse gas emissions.…”