Nonequilibrium Plasma Reforming of Greenhouse Gases to Synthesis Gas

Abstract

The use of dielectric-barrier discharges (DBDs) is a mature technology originally developed for industrial ozone production. In this article, it is demonstrated that DBDs are also an effective tool to convert the greenhouse gases CH4 and CO2 to synthesis gas (syngas, H2/CO) at low temperature and ambient pressure. The synthesis gas produced in this system can have an arbitrary H2/CO ratio, mainly depending on the mixing ratio of CH4/CO2 in the feed gas. Specific electric energy, gas pressure, and temperature hardly influence syngas composition. The amount of syngas produced strongly depends on the electric energy input. CO2-rich mixtures prevent carbon and wax formation. At fixed specific input energies, the maximum amount of syngas with low H2/CO molar ratio is produced from a mixture of CH4:CO2 = 20:80. In a mixture of CH4:CO2 = 80:20, as high as 52 mol of H2 and 14 mol of CO have been obtained from 100 mol of feed gas at a specific input energy of 87 kW h/(N m3). CH4 conversion reaches 64%, and CO2 conversion is 54%. High temperatures lead to wax formation and carbon deposition in CH4-rich feeding mixtures. Low gas pressures favor syngas production.

Methane conversion using a high‐frequency pulsed plasma: Discharge features

“…AC and DC corona discharges, dielectric-barrier discharge, arc plasma, and the combination of microwave plasma and catalysts have been reported to produce acetylene, ethylene, hydrogen, methanol, and other liquid products (Wan, 1986;Mallinson et al, 1987;Bhatnagar and Mallinson, 1995;Liu et al, 1996;Thanyachotpaiboon et al, 1998;Onoe et al, 1997;Okumoto et al, 1998;Suib and Zerger, 1993;Marun et al, 1999;Eliasson et al, 2000;Yao et al, 2000d). Recently, methane reforming with CO, using plasmas, which may contribute to effective utilization of methane and reduction of greenhouse gas CO, emission, has been reported (Gesser et al, 1997;Bromberg et al, 1998;Larkin et al, 1998;Zhou et al, 1998;Huang et al, 2000;Yao et al, 2000b).…”

Investigation of Dry Reforming of Methane in a Dielectric Barrier Discharge Reactor

“…As an alternative, the cold plasma generated by different discharge types provides a new way for the chemical process, such as chemical synthesis, treatment of hazardous waste and surface modification [12]. For the process of dry reforming of CH 4 , different discharge types to generate the cold plasma were investigated, such as gliding arc gas discharge [13][14][15], pulsed glow discharge [16], radio-frequency discharge [17,18], pulsed microwave discharge [19], two pins discharge [20], pulsed corona discharge [21], AC discharge [22], and especially the dielectric barrier discharge (DBD) [23][24][25][26][27], etc. The DBD is the most commonly used type to produce the cold plasma with energetic electrons at atmosphere pressure [28].…”

Methane conversion using a high‐frequency pulsed plasma: Important factors

“…Recent progress in plasma chemistry was reviewed (Chang et al, 1991;Eliasson and Kogelshatz, 1991). Methane plasma conversion was also summarized elsewhere (Bhatnagar and Mallinson, 1995;Thanyachotpaiboon et al, 1998;Zhou et al, 1998). The outline of methane conversion using a pulsed plasma as a kind of nonthermal plasma was given in this journal under the title "Methane Conversion Using a High-Frequency Pulsed Plasma: Discharge Features" (Yao et al, 2000a).…”