Atmospheric Pressure Portable Catalytic Thermal Plasma System for Fast Synthesis of Aqueous NO3 and NO2 Fertilizer from Air and Water

Abstract

AbstractMeaningful deployment of plasma water-based nitrogen fixation in agricultural application is hindered primarily due to its poor synthesis rate in compact systems. The study reports a directly deployable thermal plasma based portable catalytic compact system, offering typical synthesis rate as high as 1035 mg/min for nitrate and 635 mg/min for nitrite directly from naturally abundant atmospheric air and water. Developed technology is clean, sustainable, easily decentralizable, and completely free from fossil fuels and harmful intermediates like ammonia. The system avoids safety hazards and costs related to the requirements of continuous energy resources, pressurized environment for synthesis, regulated storage, refrigeration need, transportation of raw materials and distribution of fertilizer, as may be required by other competing technologies. Described system, consisting of air plasma torch, reaction chamber, water injection manifold and catalytic bed creates a unique nascent reactive plasma environment at ambient pressure that auto activates the catalyst in the field of thermal plasma for highly efficient fixation of nitrogen. Presented results indicate that use of combination catalysts with mechanically enhanced surface area allows drastic enhancement in the nitrogen fixation. Possible reaction chemistries, results of trials with different catalysts, time evolution of concentration, auto-conversion from nitrite to nitrate in aqueous media, time stability of concentration of the synthesized nitrate and observed remarkable effectiveness in the actual field trials are presented. Achieved synthesis rates are compared with those reported in literature in the area of thermal and non-thermal plasma.