Fuel and related compositions – Solid carbonaceous fuel dispersed in a liquid medium – The liquid medium is – or contains – hydrocarbon
Reexamination Certificate
1999-02-23
2001-06-19
Medley, Margaret (Department: 1714)
Fuel and related compositions
Solid carbonaceous fuel dispersed in a liquid medium
The liquid medium is, or contains, hydrocarbon
Reexamination Certificate
active
06248140
ABSTRACT:
S
TATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable.
FIELD OF THE INVENTION
The present invention relates to a fuel composition. More particularly, the present invention relates to a fuel composition derived at least in part from one or more waste streams. Still more particularly, the present invention relates to a fuel composition that is comprised of components from petroleum refining wastes, wastes from aluminum smelting processes, waste generated in the automotive, appliance and paint industries, and additional hydrocarbon streams.
BACKGROUND OF THE INVENTION
Waste product streams containing primarily water and smaller amounts of nonaqueous liquids and solids, both organic and inorganic, are by-products of processes used in various industries such as the refining, petrochemical and chemical industries, to name a few. For example, a typical waste stream from a refinery operation will contain about 80 percent-by-weight water, about 15 percent-by-weight oil, e.g., hydrocarbons and other nonaqueous liquids, and about 5 percent-by-weight solids. Other processing operations generating similar waste streams include aluminum smelting, and paint, appliance, and automotive manufacturing. Due to environmental regulations, these waste streams pose disposal problems.
It is known to treat a refinery waste stream, commonly referred to as sludge, which is a mixture of solids, water and oil products. Such sludge is treated to obtain either a solids stream that is a slurry of solids, both inorganic and organic, in a primarily aqueous medium, the slurry generally containing from about 15 to about 20 percent-by-weight solids content, or a non-pumpable dry solids cake. Such slurries, containing a relatively small amount, i.e., less than about 10 percent-by-weight, of nonaqueous liquids, e.g., hydrocarbons, can be incinerated. For example, they can be incinerated in furnaces used in spent sulfuric acid regeneration plants, cement kilns or the like. These prior art aqueous slurries have several disadvantages. For one, because of the high water content, they have a low heat value. Additionally, the solids content of the slurries cannot exceed about 20-25 percent lest they become so viscous as to be unpumpable at ambient temperature conditions. Accordingly, the cost of disposing of the slurries is increased because the transportation costs per unit weight of solids is relatively high. In the case of non-pumpable, dry solids cake, the solids content is generally 25 to 90 percent-by-weight. This cake requires special handling for disposal and is considerably more expensive than the slurries to dispose of.
The present invention overcomes the deficiencies of the prior art.
SUMMARY OF THE INVENTION
The present invention provides a method for disposing of at least a portion of such sludges and waste streams in a cost effective manner. Another object is to provide a disposal method that allows the recovery of some of the energy value in the waste stream. It is a further object of the present invention to provide a new fuel composition that is pumpable. Another object of the present invention is to provide a pumpable fuel composition derived from a waste stream containing water, nonaqueous liquids, inorganic solids and organic solids. Still a further object of the present invention is to provide a pumpable fuel composition having a relatively high solids content that can be disposed of more economically. The above and other objects of the present invention will become apparent from the description given herein and the claims.
The present invention provides a fuel composition comprising less than about 10 percent-by-weight water, greater than about 35 percent-by-weight solids, generally up to about 70 percent-by-weight solids, and from about 30 to about 65 percent-by-weight of a nonaqueous liquid. The fuel composition has a minimum heat value of about 5,000 BTU per pound and more preferably about 7,000 BTU per pound and a viscosity such that the composition is pumpable at ambient temperature. Depending on the source of the waste stream, one preferred embodiment of the present invention comprises a fuel composition comprising less than about 5 percent-by-weight water, greater than about 30 percent-by-weight solids, and from about 30 to about 65 percent-by-weight of a nonaqueous liquid and having a minimum heat value of about 10,000 BTU per pound
DESCRIPTION OF THE PREFERRED EMBODIMENT
The fuel composition of the present invention comprises water, solids and nonaqueous, liquids. Generally speaking, the water will be present in an amount of less than about 10 percent-by-weight, more preferably in the range of from about 0 to about 8 percent-by-weight. The solids, which can include both inorganic and organic containing materials, will comprise greater than about 35 percent-by-weight, generally up to about 70 percent-by-weight, the solids stream generally comprising from about 50-70 wt % inorganic solids and from about 30-50% organic solids. For certain waste streams, the organic solids are carbon-containing compounds that are substantially methylene chloride insoluble, but because of their carbon content are usually combustible. In other cases, the solids content can be substantially all organic, i.e., carbon-containing, or all inorganic. According to the present invention, the solids comprise particles having an average size less than 250 microns. If the solids initially present in the waste stream are larger than the preferred size, it is preferred that the process include a grinding step to reduce their size to the preferred range.
The nonaqueous liquids will generally comprise from about 30 to about 65 percent-by-weight of the fuel composition. The nonaqueous liquid can be virtually any combustible organic material. The nonaqueous liquid may be insoluble in water or have limited solubility in water. Non-limiting examples of suitable nonaqueous liquids include hydrocarbons, alcohols, ketones, ethers, aldehydes, etc., as well as mixtures of such compounds. Typically, the nonaqueous liquids are referred to as “oil” or “solvent.” As used herein, oil refers to any mixture of organic compounds typically found in waste streams or sludges in refineries, petrochemical plants and the like, which are generally immiscible with water. While such oils primarily comprise hydrocarbons, other organic compounds can also be present. Similarly, “solvent” refers to any mixture of organic compounds typically found in waste streams from manufacturing waste, paint waste and the like. While such solvents primarily comprise hydrocarbons, other organic compounds can also be present. The liquid hydrocarbons are optionally obtained from the same type of waste stream as said solids.
The fuel compositions of the present invention can also include dispersant and/or surfactants such as lignosulfonates.
The fuel composition may have a heat value as low as 5,000 BTU per pound, but will preferably have a minimum heat value of at least about 7000 BTU per pound, more preferably greater than about 8,000 BTU per pound, and still more preferably at least about 10,000 BTU per pound.
The fuel composition of the present invention, because it has a relatively high content of liquids that are less polar than water, does not become viscous, rendering it unpumpable at ambient temperature. Prior art slurries used for fuel in furnaces or cement kilns suffer from the disadvantage that, because the water content is high, the solids content must be kept below about 25 percent-by-weight in order that the slurry can be handled by conventional pumps. As can be seen, the fuel composition of the present invention contains a minimum of about 30 percent-by-weight solids are optionally at least 40 percent by weight solids and can contain about up to about 70 percent-by-weight solids and still be pumpable. This high solids loading is further advantageous in that transportation and disposal costs per unit weight of solids is reduced.
In the disposal of a typical waste stream, e.g., a refinery waste stream, EPA regulations including Boiler
Genssler Klaus
Ruth Raymond R.
Conley & Rose & Tayon P.C.
Medley Margaret
Scaltech Inc.
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