Coal Liquefaction by Using Dielectric Barrier Discharge Plasma

Abstract

An innovative method for coal liquefaction by using dielectric barrier discharge (DBD) plasma in a short reaction time was developed. Using tetralin as the reaction medium, DBD plasma as the energy source, and a reaction time of 10 min at 140 o C, up to 10% of coal was converted to liquid material. The results showed the feasibility of coal's liquefaction by DBD plasma under relatively moderate conditions. Simultaneously, it was clarified that the effect of DBD plasma treatment was opposed to the thermal effect of heating. An acid plasma sheath could be formed on the coal powder surface in DBD conditions, liquefied reactions could be carried out in the absence of inorganic acid, and the products were nearly neutral and with low causticity.

High‐Performance Plasma‐Enabled Biorefining of Microalgae to Value‐Added Products

“…Driven by the electric field, these electrons will gain significantly greater speeds than ions, and this leads to the accumulation of negative charge on the biomass surface. This surface charge then acts as a barrier that prevents negatively charged OH − ions from reaching the biomass surface and at the same time attracts more positively charged H + ions . Therefore, the degradation pathway for plasma catalytic conversion of biomass mainly involves generation of electrons and free radicals, acceleration of electrons, radicals, and ions (H + or OH − ), heat accumulation and thermal degradation or oxidation of biomass through both free‐radical reactions, which mainly include dehydration, decarboxylation, deamination and other bond‐scission reactions, and ionic pathways, similar to high‐temperature solvolysis (general conversion pathways of the PCL of C. pyrenoidosa are also detailed in Figure c) …”