Precision Combustion, Inc. (PCI) is applying its experience in catalytic combustion to the remediation of contaminated sub-surface or surface soils through the application of low to high pressure, high temperature steam directly into contamination zones. Building upon our experience in catalytic direct-fired steam generation, the products currently in development can be used as (i) a complementary process to other techniques; (ii) as the primary approach for cleaning up affected areas; and/or (iii) to create a thermal or fluid barrier or “wall” around the perimeter of a pollution zone to prevent plumes from migrating to non-polluted areas, water zones, etc. The system is designed for ~300-1000°C operation and extremely high rates of heat and mass injection in relatively short times, which shortens dwell times and reduces total energy required.

Conventional thermal treatment technologies (electric conductive or resistive heating) are effective in removing contaminants, such as diesel fuel, crude oil, DNAPLs (dense non-aqueous phase liquids) and mercury, but these techniques are typically both costly and slow. A very large energy input is required to generate the required heat (>250 °C in the case of mercury), and long dwell times are required to elevate the soil region to the necessary temperatures. The high costs of thermal remediation present a significant barrier to effective and timely site restoration.

PCI’s catalytic direct-fire steam generator avoids the inherent problems of conventional boilers. The disadvantages of boilers include high energy costs, high water usage, high CO2 emissions, as well as temperature limits of about 100 °C for saturated steam. PCI’s catalytically stabilized, direct-fire design provides significant energy savings vs. boilers and operates at ~300-1000°C, where boilers cannot, to enable effective in-situ remediation. It also produces super-heated steam with water contents over 60% for improved volatilization and removal.

PCI’s direct steam generator is based upon our well-established natural gas-fired catalytic combustor technology. The combustion process generates steam and combustion end products, with the steam containing about 70% of the thermal energy produced. These fluids are injected into a perforated pipe sections that release heat and mass flows into the contaminated soil zone, at temperatures from 100 to 1000 °C and from shallow to depths to at least 300 feet. The system is compact, tightly controllable, and capable of very high BTU output. The catalytic combustor is able to burn gaseous or liquid fuels.

The hardware can be configured to be placed into a pipe for insertion into the treatment area. Alternatively, the steam generation hardware could be located on the surface and steam piped into the area via a manifold approach. In this setup, a single PCI device could support multiple injection wells, depending on the configuration and requirements for energy input, pressure and temperature.