Hot air injection

Steam (or hot air) injection requires the placement of injection wells outside the contaminated area and extractions near the center of the targeted treatment area. 

Soil vapor extraction is a commercially proven technology, and according to the vendor, the Vaportech enhanced volatilization method has been used in many full-scale remediations. The developer has performed held studies using hot air injection to further enhance the performance of this technology. The Vaportech technology is commercially available from Envirogen, Inc., formally MWR, Inc. 

The installation cost of a hot-air injection system including stainless steel wells is about 15,000 to 22,000 for a 50-kW system. The electricity would cost about 3600 per month. These costs do not include the vapor extraction portion of the system. 

Hot air injection and cyclic in situ combustion have been used to consolidate sand (96). Oil in the near wellbore region undergoes cracking with the formation of coke, which serves to consolidate the sand grains. 

The in situ combustion method of enhanced oil recovery through air injection (28,273,274) is a chemically complex process. There are three types of in situ combustion dry, reverse, and wet. In the first, air injection results in ignition of cmde oil and continued air injection moves the combustion front toward production wells. Temperatures can reach 300—650°C. Ahead of the combustion front is a 90—180°C steam 2one, the temperature of which depends on pressure in the oil reservoir. Zones of hot water, hydrocarbon gases, and finally oil propagate ahead of the steam 2one to the production well. 

This hot air converts the injected fuel from an atomized liquid to a vapor to permit self-ignition (it establishes a flame front) ivithout the need for a spark plug. 

Thermal enhancement of volatilization.19 21 Volatility of contaminants increases greatly with temperature, so several techniques have been developed to raise soil temperature, including the injection of hot air or steam, electrical resistance heating, and radio frequency heating. 

Aqueous Ammonia Aqueous ammonia is also injected into the flue gas as a vapor, but since it is typically 19-29% ammonia, the water must be vaporized by use of hot air. Ambient air is pumped through an electric heater into a vaporizing vessel. Aqueous ammonia is sprayed into the top of the vessel where it contacts the heated air. The NHj/air mixture then proceeds to the AIG. 

Very groat benefits are derivable from this property of fluids. It has been advantageously op plied in the ventilation of buildings, the hot air rising to the top and escaping, while cool air is injected. It is upon this principle also that Perkins s apparatus for the heating of dwellings is constructed. This is represented in its simplest form in Fig,... 

Mullins has conducted an extensive program to determine the spontaneous ignition of fuels injected into hot air streams. His experimental apparatus is discussed (16C). 

Mullins, B. P., Studies on the Spontaneous Ignition of Fuels Injected into a Hot Air... 

Forward Combustion Injection of hot air into deposit to effect distillation and thermal cracking (Pan American Petroleum)... 

Combined Combustion/ Injection of hot air into production well to Steam Drive promote combustion steam injected into pro-... 

First station usually has multiple preform injection molds where preforms are formed over core pins. The preforms have hemispherical closed ends (resembles a laboratory test tube). The other ends have an open bore, formed by the core pin. External details, such as the thread and neck flange for a screw-top container, are directly produced by injection molding. While the preform is still hot, the injection split mold is opened and the preforms, still on the core pins, are rotated to the blowing station two. Here the preforms are enclosed within the blow mold, and introducing blowing air through the core pins followed with cooling produces the BM. Blow molds opened and the finished products, still on the core pins, are rotated to an ejection station where they are stripped off mechanically and/or air. 

---