From: Public Services and Procurement Canada
Hot gas decontamination consists of raising the temperature of a contaminated material to 260 °C (500 °F) by exposing it to hot gases, such as propane or natural gas, for a specified period of time. The contaminants present are thermally destroyed (by combustion or pyrolysis) or volatilized. The gas effluent (volatilized contaminants) from the material is extracted from the furnace and treated in an incinerator. This technology specifically applies to the remediation of materials contaminated with explosives (demilitarized mines, bomb residues or soils from training or military battlefields). The hot gas decontamination treatment is also applicable to the remediation of buildings or structures associated with munition plants, arsenals and depots involved in the manufacture, processing, loading, and storage of pyrotechnics, explosives and propellants. The method consists of sealing and isolating structures and heating them with a stream of hot gas.
The gas injection system is generally composed of a furnace containing the contaminated materials in which the hot gases are injected, as well as fans, a gaseous emission control system and an incinerator. Following the treatment of explosives in the furnace, gaseous emissions (volatilized contaminants) are directed to the incinerator where they are treated. The incinerator is equipped with a gas concentration meter to monitor and control the concentration of contaminants in the air. The furnace design must provide for the possibility of explosion during the hot gas injection treatment.
The incinerator including the effluent gas treatment system can be constructed temporarily on-site.
The implementation of this technology may include:
The installation of a temporary incinerator for the treatment of residual gases is subject to compliance with certain laws and regulations that may require obtaining permits or authorizations.
Due to the types of systems to be put in place and the energy required for their operation, this technology does not seem appropriate in northern regions. Similarly, the operation of this type of technology requires rigorous monitoring by specialized personnel who may not be available in this type of environment.
None.
The hot gas furnace chamber design must take into consideration possible explosions from improperly demilitarized mines or shells.
A large number of compounds can be volatilized during hot gas injection and incineration requires monitoring of the composition of the air before it is released to the environment.
The following site provides an application example:
The United States Army Environmental Center sponsored several demonstrations showing that 99.9% decontamination of structural components is possible. Items decontaminated for 6 hours at a minimum temperature of 260 °C (500 °F) were found to be safe for public release as scrap.
Main Exposure Mechanisms
Applies or Does Not Apply
Monitoring and Mitigation
Dust
Does not apply
N/A
Atmospheric/Steam Emissions—Point Sources or Chimneys
Applies
Emissions monitoring (choice of parameters and levels of intervention depending on source, risk and local requirements).
Atmospheric/Steam Emissions—Non-point Sources
Air/steam—by-products
Emissions monitoring (choice of parameters, types of samples and type of intervention [source, risk or local requirements]).
Runoff
Groundwater—displacement
Groundwater—chemical/ geochemical mobilization
Groundwater—by-product
Accident/Failure—damage to public services
Verification of files and obtaining prior permits.
Accident/Failure—fire or explosion (inflammable vapours)
Risk review, development of accident and emergency response plans, monitoring and inspection of unsafe conditions
Other—Handling contaminated soils or other Solids
Composed by : Josée Thibodeau, M.Sc, National Research Council
Updated by : Martin Désilets, B.Sc., National Research Council
Updated Date : April 17, 2013
Latest update provided by : Nathalie Arel, P.Eng., M.Sc., Christian Gosselin, P.Eng., M.Eng. and Sylvain Hains, P.Eng., M.Sc., Golder Associés Ltée
Updated Date : March 22, 2019
