Review on an advanced combustion technology: Supercritical hydrothermal combustion

Abstract

Supercritical hydrothermal combustion, a new and promising homogeneous combustion technology with a wide range of application scenarios and broad development prospects, provides creative ideas and means for the enhanced degradation of organic wastes, hydrothermal spallation drilling, thermal recovery of heavy oil, etc. This technology is elaborated upon in five parts: (1) introducing the main devices including semi-batch reactor and continuous reactor to study the hydrothermal flame in accordance with research institutions, (2) presenting the research status of related numerical simulation from the angles of reaction kinetics and flow-reaction, (3) summarizing the characteristics of hydrothermal flame and combustion by five key parameters, (4) dividing up ignition process and explaining ignition mechanism from the perspectives of critical physical properties of water and heat transfer and mixing conditions, (5) discussing and forecasting its industrial applications including hydrothermal spallation drilling, the thermal recovery of heavy oil, the clean conversion and utilization of coal-based fuel, and the harmless treatment of pollutants. By and large, this paper analyzed in detail everything from experimental equipment to industrial applications, from combustion characteristics to ignition mechanisms, and from summary conclusions to prospect prediction. In the end, herein is summarized a couple of existing paramount scientific and technical obstacles in hydrothermal combustion. Further significant studies in the future should include excellent reactors, advanced monitoring techniques, and powerful computational fluid dynamics.