Supercritical water oxidation: An emerging technology

Supercritical Water Gasification of Municipal Sludge: A Novel Approach to Waste Treatment and Energy Recovery

“…Corrosion has historically impeded SCW commercialization due to limited reactor life (Barner et al, 1992;Hodes et al, 2004). Metal corrosion in SCW systems is driven, in part, by water's own natural solvation characteristics and is largely localized to areas where water drops below the critical point (Marrone & Hong, 2009).…”

“…The high fluid velocities overcome salt nucleation and agglomerate adhesion via high shear forces, in combination with scouring effects of entrained inorganic solids such as sand . Tubular reactors have become the overwhelming technology of choice for commercial applications in part because of their salt control advantages (Barner et al, 1992;Bermejo & Cocero, 2006b;Brunner, 2009a;Cabeza et al, 2011;Matsumura et al, 2005). Well over 80% of the industrial applications of supercritical treatment of industrial wastewaters use tubular reactors coupled with a countercurrent heat exchanger for increased efficiency (Vadillo et al, 2011;Vogel et al, 2005).…”

“…Recycling heat from the hot effluent through heat exchangers back to the incoming, pressurized feedstock achieves a positive energy balance and acceptable system efficiency, which is critical to overcoming the high enthalpy of water (Abelleira et al, 2011;Cocero, 2001;Matsumura et al, 2005). Preheating temperature (to well above the critical point 375°C) can also be a very important optimization (or simulation) consideration, especially when dealing with dilute or lowheating-value feedstocks (Barner et al, 1992;Cocero, 2001;. High preheating demand can be offset by supplementing the feed stream with a liquid, highheating-value "fuel" such as waste oils or discarded organic solvents from industrial processes (Barner et al, 1992;Cocero, 2001;.…”

“…Preheating temperature (to well above the critical point 375°C) can also be a very important optimization (or simulation) consideration, especially when dealing with dilute or lowheating-value feedstocks (Barner et al, 1992;Cocero, 2001;. High preheating demand can be offset by supplementing the feed stream with a liquid, highheating-value "fuel" such as waste oils or discarded organic solvents from industrial processes (Barner et al, 1992;Cocero, 2001;.…”

“…The most prevalent message from recent works is that CSCWG shows great scientific promise as well as notable technologic and commercialization feasibility for hydrogen production from biomass (Calzavara et al, 2005). Supercritical water oxidation (SCWO) research dates back a bit further than either SCWG or CSCWG, but most of the research occurred as greater interest developed at universities, national laboratories, and government agencies in the late 1980s (Barner et al, 1992). Despite its early beginnings, SCWO now has only a slightly larger percentage of overall supercritical water research (27.8%) than SCWG (23.1%).…”