Supercritical Water Oxidation Process

ChemTech Innovators R&D Center

The supercritical water oxidation unit comprises of an 8 ft by 12 ft by 8 ft steel enclosure which is segmented and floor mounted. The front of the enclosure has operator accessible valves, pressure gauges, water reservoirs, booster pump control, and electronics controls for heaters, mass flow, and pump operational the front of the unit. While in operation the interior of the unit is inaccessible. The gas pressure development and delivery are specially cleaned for oxygen service, since the unit uses pure oxygen as an oxidizer instead of air.

Reactor: 1000 mL Hastelloy C276 Agitated Bolt Closure, Autoclave Engineers
Reactor MAWP: 6000 psig at 650°F
Modes of Operation: Batch, semi-batch, continuous
Working Fluid: Principle working fluid is water and mixtures of water and oxygen.
Pressure Development: Booster pump (pneumatically driven compressor) and micro-metering pump
Control and Acquisition: Electronic PID heater control, Electronic PID mass flow control, pneumatic PID pressure control, operator based data acquisition.
Principle Applications: Supercritical water oxidation applied towards chemical and biological counterterrorism, destruction of toxins, remediation, depolymerization, low temperature fuel reformation, water purification, etc.

In the interior of the enclosure for the supercritical water oxidation unit is the 1000 mL reactor, pneumatically driven booster pump, micro-metering water pump, pneumatically actuated control valve, and mass flow controllers for oxygen feed control and inert feed control.  The reactor vessel is made of Hastelloy C276, which has a better resistance to chlorine pitting than Inconel 625.  Since supercritical water oxidation can be highly exothermic (generates heat) several measures are taken for overpressure control and protection. In the event of thermal runaway resulting in pressure runaway, the system is protected by a rupture disc assembly and a 54 gallon pressure diffusion drum. In addition, the top of the enclosure has two blow-out panels to all for additional diffusion in an unlikely event of uncontrolled over-pressurization. All lines valves, regulators, pumps, and controllers, that handle oxygen have been specially cleaned for oxygen service to prevent in-line flames.