Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including solid reactant and means charging solids into – or...
Reexamination Certificate
1998-08-18
2001-08-07
Beck, Shrive (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including solid reactant and means charging solids into, or...
C422S210000, C202S117000, C202S118000
Reexamination Certificate
active
06270735
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The invention relates to the recovery or removal of organic compounds from soil, refinery tailings, and the like. The invention is particularly suited for removing light oils, pesticides, heavy oils or tar and/or other hazardous chemicals from soil which has been contaminated with such chemicals.
BACKGROUND OF THE INVENTION
Soils which have become contaminated with various organic compounds such as oils or pesticides, for example, must be treated to remove the contaminating material in order to prevent the contaminating material from leaching into adjacent areas and ground water. Certain refinery tailings may also contain harmful organic compounds with must be removed before the tailings can be landfilled or otherwise released to the environment.
Organic compounds may be removed from contaminated soil and certain refinery tailings and the like by subjecting the contaminated material to heat. This heat treatment for removing organic compounds is commonly referred to as “thermal stripping.” Relatively low temperatures cause light oils and other hydrocarbon contaminants to go into a gaseous phase in which the contaminant releases from the contaminated material. Heavier oils may be driven out of the contaminated material in a gaseous phase at higher treatment temperatures. Even higher temperatures may be used to break chemical bonds in organic compounds such as pesticides, and allow the constituent elements or chemicals to release from the contaminated material. While it has been known to remove organic compounds from contaminated soil and the like through thermal stripping, prior thermal stripping processes have not provided sufficient control to accommodate the many different types of contaminants which may be present in the contaminated soil.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an apparatus and method for removing organic compounds from soil, refinery tailings, and other similar waste streams. More particularly, it is an object of the invention to provide an apparatus and method which facilitates a high degree of control in the removal of organic contaminants from waste streams such as contaminated soils.
An apparatus embodying the principles of the invention is made up of one or more units, the number of units depending upon the types of contaminants to be removed from the particular waste stream. Each unit comprises a heated pipe having an inlet end and an outlet end. The pipe is heated preferably by electrical induction heating and transfers heat to the waste stream contained therein. A transport unit is mounted inside the heated pipe for transporting the waste stream there through and mixing the waste stream to provide uniform heating in the material. According to the invention, the transport unit is adjustable so that the rate at which the waste stream passes through the pipe may be closely controlled without eliminating the mixing action produced by the transport unit.
The transport unit comprises a dual line of substantially semi-circular transport segments pivotally mounted on opposite sides of a hollow mounting cylinder. The mounting cylinder itself is concentrically mounted within the heated pipe for rotation about its longitudinal axis. A drive unit is associated with the mounting cylinder for rotating the mounting cylinder about its longitudinal axis. The uppermost end of a pivotal mounting rod for each segment is connected to a spring-loaded scraper blade for scraping the inner wall of the pipe to help mix the material passing through the pipe and prevent buildup on the pipe walls which could reduce heat transfer to the waste stream. The lower end of each mounting rod extends through a bearing into the hollow mounting cylinder and is operatively connected by a lever arm to a threaded rod that extends through the mounting cylinder. The lever arm and threaded adjusting rod cooperate to adjust the angle of each row of transport segments. For maximum transport at a particular speed setting of the drive for the transport unit, the angle of each row of segments is set equal and opposite with the leading edge of one row of segments being approximately above the trailing edge of the opposite row of segments. At any one speed, decreasing the angle of each row of segments with respect to a line perpendicular to the mounting cylinder will give more mixing and slower transport.
One unit according to the invention may be used for treating a waste stream to remove water and low-boiling point organic compounds by thermal stripping. A plurality of units according to the invention may be used in series to remove contaminants by both thermal decomposition and thermal stripping. For example, three units may be used in series to treat a waste stream comprising a contaminated soil including water, low-boiling organic compounds, high-boiling organic compounds, and normally solid compounds such as pesticides and insecticides. The first unit in the series may be operated with the exit temperature held at about 100 degrees centigrade. Water vapor and organic compounds released in the first unit are preferably vented to a suitable condenser to condense the water vapor and organic compounds.
The solids from the outlet of the first unit feeds into the second unit. The second unit is equipped with a vent line leading to a condenser to condense the higher-boiling organic compounds for recycle and the exit temperature may be held at 200 to 300 degrees centigrade. The solid material discharged from the second unit feeds into the inlet end of the third unit. The exit temperature of the third unit may be held at 750 to 950 degrees centigrade to crack organic compounds remaining in the waste stream. The third unit in the series is equipped with a vent line and a suitable scrubber for removing elements such as chlorine and bromine from the vent gases.
The process control achieved with the invention makes the present treatment apparatus and method suitable for treating soils and the like contaminated with many different types of organic contaminants. In waste streams containing only light organic contaminants or organic contaminants plus water, the apparatus provides thermal stripping to produce a landfillable solids output while separating the water and lower boiling point organics. The apparatus according to the invention may also decompose organics such as insecticides, and remove the resulting constituent elements or compounds. In waste streams containing organic contaminants plus metals that must be removed before the solids may be placed in a landfill, the apparatus according to the invention can be used as a pretreatment before metal removal. This pretreatment may be particularly useful where metal removal is to be accomplished by leaching or by molten metal contact as outlined in U.S. Pat. No. 5,000,101.
These and other objects, advantages, and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings.
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Beck Shrive
Clean Technologies International Corporation
Culbertson Russell D.
Doroshenk Alexa
Shaffer & Culberton, LLP
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