A SOLID FUEL COMPOSITION WITH HIGH CALOFIC VALUE
FIELD OF THE INVENTION
[0001] The present invention generally relates to recovery of the energy values of oil refinery sludge and waste crumb rubber. More particularly, the present disclosure provides a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber that can be used in a rotary mineral processing kiln, such as a lime, light-weight aggregate, asphalt, cement kiln, brick industry and the likes.
BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Petroleum refineries have a need to dispose of the wastes comprised of oily sludges (oil-solid or oil-solid-water mixtures) produced in waste water treatment facilities and hydrocarbon storage tanks. In recent times, tank bottom wastes, sometimes referred to as sludge and often shortened to just tank bottoms, have become an increasing problem since their regulation has often classified them as environmentally hazardous wastes with the corresponding difficult and expensive handling problems. However, by appropriate processing, this designation can wane off and the resulting constituents can become potential products/materials or can be disposed of in an ordinary manner. Additionally, their composition, being a mixture of hydrocarbon, solids and water, is unacceptable for refineries, which would require the removal of significant portions of solids and water.
[0004] The amount of this potential tank bottom waste builds to large quantities, not only because of the large oil field, pipe line, and refinery capacities in this country, but also because of the storage of these tank bottoms until some disposal method can be employed. Particularly, in remote oil fields, far from refineries, storage needs to be continued for many years. Most of these wastes are disposed of by microbial treatment on large area of land at a site. However, certain types of oily sludge cannot be land treated due to the bio-refractory nature of the oil contained therein. For example, some refinery tank bottom sludge (e.g., Coker hot slop tank sludge and cat fractionator’s bottoms sludge) contain viscous oil and high levels of bio refractory polynuclear aromatic components, which are not 2
suitable for disposal through land treatment. Removal of bio-refractory oil from oily sludges in order to make them suitable for land treating could be an attractive waste management option. However, conventional de-oiling processes and services are costly and in some cases do not achieve the desired result. For example, extraction based technologies using special solvents rely on recovery and recycling of the solvent and may leave asphaltene fractions of the oil on the solids.
[0005] Hundreds of millions of tires are discarded across the world every year. Disposal of waste tires is a challenging task because tires have a long life and are non-biodegradable. The traditional method of waste tires management have been stockpiling or illegally dumping or land filling, all of which are short-term solutions. Crumb rubber is a term usually applied to recycled rubber obtained from automotive and truck scrap tires. There are two major technologies for producing crumb rubber – ambient mechanical grinding and cryogenic grinding. Of the two processes, cryogenic process is more expensive but it produces smoother and smaller crumbs.
[0006] US patent 5269234 discloses a method for utilizing land fill prohibited solid hazardous waste material as an energy source in a cement kiln. The method comprises combining the solid waste materials with a liquid fuel in a milling apparatus to form a mixture, grinding the mixture in the milling apparatus in a manner reducing the particulate size of the solid hazardous waste material to form fuel slurry, and delivering the fuel slurry directly into the flame of the cement kiln.
[0007] US patent 5495986 discloses a method for providing a fuel mixture by processing refinery sludge and blend stock, which provides fuel. The process contains steps of grinding the waste material in a tank containing the blend stock with the grinding being in at least part provided by the co-action between a rotating impeller and a stationery plate.
[0008] US patent 5259945 discloses a process for the recovery of tank bottom wastes employing a flash tank fed with hot, pressurized tank bottom wastes and separating a vapor component and heavier bottoms then fed to a stripping reactor along with hot gas producing an overhead vapor with a solid remainder. Tank bottom sludge is employed as fuel.
[0009] US patent 5288391 discloses a process for de-oiling wastes. The process is integrated with a refinery and utilizes a refinery intermediary hydrocarbon stream as a solvent to recover waste oil for reprocessing in the refinery and to produce waste solids, which are either reused or disposed for land treatment. US patent 5078593 discloses a method for disposal of oil refinery sludge containing a hydrocarbon component, a solid component comprising sediments such as sand, silt, rust or scale, and water in an operating rotary kiln.
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[00010] US patent 4786401 discloses a liquid sludge disposal process wherein hydrocarbon-containing liquid waste sludge from refinery waste streams can be disposed of by blending with the feedstock being passed in a fluid catalytic cracking unit. The sludge is premixed with a hydrocarbon, such as light oil, prior to mixing with the feed. However, by mixing with FCC feed, it may damage the catalyst due to poisonous metals and high nitrogen and also leads to high emissions and change in product slate.
[00011] A person skilled in the pertinent art would immediately realize one or more disadvantages associated with these conventional compositions and methods for manufacture thereof. Accordingly, there remains a need in the art for compositions that can not only alleviate the problem of disposal of such waste and hazardous materials, but which can be utilized directly as a fuel with high calorific value without further treatment thereof. The present disclosure generally satisfies the existing needs and overcomes the one or more drawbacks associated with conventional fuel compositions and methods for production thereof.
OBJECTS OF THE INVENTION
[00012] Primary object of the present invention to provide a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber.
[00013] Another object of the present invention is to provide a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber with high calorific value.
[00014] Another object of the present invention to provide a solid fuel composition that is economical to produce.
[00015] Another object of the present invention to provide a solid fuel composition that effects disposal of waste and potentially hazardous materials.
[00016] Another object of the present invention is to provide a method of preparation of a solid fuel composition from waste and potentially hazardous materials.
[00017] Another object of the present invention is to provide a method of preparation of a solid fuel composition from waste and potentially hazardous materials that can find utility in rotary mineral processing kiln, such as a lime, light-weight aggregate, asphalt, cement kiln, brick industry and the likes.
[00018] Other objects of the present invention will be apparent from the description of the invention herein below.
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SUMMARY OF THE INVENTION
[00019] The present invention generally relates to recovery of the energy values of oil refinery sludge and waste crumb rubber. More particularly, the present disclosure provides a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber that can be used in a rotary mineral processing kiln, such as a lime, light-weight aggregate, asphalt, cement kiln, brick industry and the likes.
[00020] An aspect of the present disclosure provides a solid fuel composition comprising a pre-defined amount of oil refinery sludge and a pre-defined amount of crumb rubber, wherein said solid fuel composition exhibits calorific value of at least 5500 calories/gram. In an embodiment, the solid fuel composition includes an extrudate including the pre-defined amount of oil refinery sludge and the pre-defined amount of crumb rubber. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio ranging from about 1:1 to about 5:1.
[00021] In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 1:1 and wherein said solid fuel composition exhibits calorific value of about 5541 calories/gram. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 2:1 and wherein said solid fuel composition exhibits calorific value of about 5900 calories/gram. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 3:1 and wherein said solid fuel composition exhibits calorific value of about 6500 calories/gram.
[00022] Another aspect of the present disclosure relates to a method of preparation of a solid fuel composition, the method including the steps of: mixing a pre-defined amount of oil refinery sludge and a pre-defined amount of crumb rubber to achieve a uniform mass therefrom; and effecting extrusion of the uniform mass using an extruder to form a solid fuel composition, wherein said solid fuel composition exhibits calorific value of at least 5500 calories/gram. In an embodiment, the method further includes a step of mixing the solid fuel composition with any or a combination of a solid fuel and a liquid fuel.
BRIEF DESCRIPTION OF DRAWINGS
[00023] The diagrams are for illustration only, which thus is not a limitation of the present invention, and wherein:
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[00024] FIG. 1 illustrates an exemplary snippet depicting oil refinery sludge, in accordance with an embodiment of the present disclosure.
[00025] FIG. 2 illustrates an exemplary snippet depicting crumb rubber, in accordance with an embodiment of the present disclosure.
[00026] FIG. 3 illustrates an exemplary snippet depicting the solid fuel composition, realized in accordance with embodiments of the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[00027] The embodiments herein and the various features and advantageous details thereof are explained more comprehensively with reference to the non-limiting embodiments that are detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein.
[00028] Unless otherwise specified, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions may be included to better appreciate the teaching of the present invention.
[00029] As used in the description herein, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00030] As used herein, the terms “comprise”, “comprises”, “comprising”, “include”, “includes”, and “including” are meant to be non- limiting, i.e., other steps and other ingredients which do not affect the end of result can be added. The above terms encompass the terms “consisting of” and “consisting essentially of”.
[00031] As used herein, the terms “composition” “blend,” or “mixture” are all intended to be used interchangeably.
[00032] The terms “weight percent,” “wt%,” “percent by weight,” “% by weight,” and variations thereof, as used herein, refer to the concentration of a substance as the weight of that substance divided by the total weight of the composition and multiplied by 100. It is understood that, as used here, “percent,” “%,” and the like are intended to be synonymous with “weight percent,” “wt-%,” etc.
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[00033] The present invention generally relates to recovery of the energy values of oil refinery sludge and waste crumb rubber. More particularly, the present disclosure provides a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber that can be used in a rotary mineral processing kiln, such as a lime, light-weight aggregate, asphalt, cement kiln, brick industry and the likes.
[00034] An aspect of the present disclosure provides a solid fuel composition comprising a pre-defined amount of oil refinery sludge and a pre-defined amount of crumb rubber, wherein said solid fuel composition exhibits calorific value of at least 5500 calories/gram. In an embodiment, the oil refinery sludge is a landfill-prohibited solid hazardous refinery tank sludge. In an embodiment, the refinery tank sludge includes water in an amount ranging from about 10% to about 30% by weight of the sludge. In an embodiment, the oil refinery sludge is a landfill-prohibited solid hazardous refinery tank sludge. In an embodiment, the refinery tank sludge includes water in an amount ranging from about 10% to about 30% by weight of the sludge. In an embodiment, the solid fuel composition includes an extrudate including the pre-defined amount of oil refinery sludge and the pre-defined amount of crumb rubber. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio ranging from about 1:1 to about 5:1.
[00035] In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 1:1 and wherein said solid fuel composition exhibits calorific value of about 5541 calories/gram. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 2:1 and wherein said solid fuel composition exhibits calorific value of about 5900 calories/gram. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 3:1 and wherein said solid fuel composition exhibits calorific value of about 6500 calories/gram.
[00036] Another aspect of the present disclosure relates to a method of preparation of a solid fuel composition, the method including the steps of: mixing a pre-defined amount of oil refinery sludge and a pre-defined amount of crumb rubber to achieve a uniform mass therefrom; and effecting extrusion of the uniform mass using an extruder to form a solid fuel composition, wherein said solid fuel composition exhibits calorific value of at least 5500 calories/gram. In an embodiment, the oil refinery sludge is a landfill-prohibited solid hazardous refinery tank sludge. In an embodiment, the refinery tank sludge includes water in an amount ranging from about 10% to about 30% by weight of the sludge. In an embodiment, the oil refinery sludge is a landfill-prohibited solid hazardous refinery 7
tank sludge. In an embodiment, the refinery tank sludge includes water in an amount ranging from about 10% to about 30% by weight of the sludge. In an embodiment, the solid fuel composition includes an extrudate including the pre-defined amount of oil refinery sludge and the pre-defined amount of crumb rubber. In an embodiment, the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio ranging from about 1:1 to about 5:1.
[00037] Typically, oily refinery sludge composition includes both organic and inorganic components, varying from one refinery to the other and often varying within a refinery depending upon time and source. Factors likely to affect the composition include crude oil characteristics, composition and quantity of water, spills and leaks, blow down, refinery housekeeping, refinery size and age, and segregation of oil drains.
[00038] Oil refinery sludge contain oil, gas fraction, water fraction and a solid fraction. Prior to dewatering, the oil and gas fraction typically contains about 15-45% by weight of the sludge and includes paraffins, napthenes, asphalts or other oils. Prior to dewatering, the solid fraction typically is in excess of about 3% by weight of the sludge and includes sediments such as sand, silt, rust, and scale and other inorganic components including various sulfur containing compounds and metals such as arsenic, barium, cadmium, chromium, lead, mercury, nickel, selenium, silver, and vanadium and compounds containing such metals. Such sludge typically contain in the range of about 40 to 90 percent water by weight prior to dewatering. In addition, the majority of the inorganic constituents of oily refinery sludge are advantageously incorporated in and contribute to the mineral value of the in-process mineral matter. FIG. 1 illustrates an exemplary snippet depicting oil refinery sludge, in accordance with an embodiment of the present disclosure. The typical composition of tank sludge utilized in the embodiments of the present disclosure and metal profile of a solid fuel composition realized in accordance with an embodiment of the present disclosure is provided in Table 1 below.
Metals
Sludge
Wt.%
Final product (4:1)
Wt.%
Copper
0.005
0.004
Aluminium
0.057
0.550
Iron
1.36
1.92
Magnesium
0.063
0.429
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Manganese
0.014
0.019
Sodium
0.053
0.101
Zinc
0.007
0.033
Nickle
0.015
0.017
Chromium
0.004
0.005
[00039] The main inorganic constituents of waste crumb rubber and sludge mixtures are alumina and silica and other metals that go through a chemical and/or physical change in the process of the present invention. Particularly in the elevated temperatures of the firing zone of the kiln, toxic metals are generally chemically combined to form non-leachable complex silicates and aluminates. These chemical components of sludge and waste crumb rubber mixtures are having good cementation properties which can add value to the final burned material. FIG. 2 illustrates an exemplary snippet depicting crumb rubber, in accordance with an embodiment of the present disclosure.
[00040] Prior to dewatering, oily refinery sludge typically have excess water content ranging from 10 to 60 wt% and an energy content of substantially less than 4000 BTU per pound (453.5 gr). In this form, the material is difficult to handle and has insufficient energy content to be used by itself as a fuel for burning. In typical cement making process, raw materials, such as clay, shale, limestone and silica are crushed in crusher and stored in raw material storage tanks. For the manufacture of cement, the raw materials are ground in the wet raw grinding mill, and slurried with water (about 34 wt. % water). The kiln feed slurry is introduced to the rotary kiln through the cold end of the rotary kiln. Coal stored in bin is ground in mill and introduced to hot end of the rotary kiln. The coal may be supplemented by fuel from supplementary fuel source. Immediately inside the rotary kiln the fuel is ignited.
[00041] The sludge and waste crumb rubber extrudates may be charged to the rotary kiln for burning in any number of methods. In one method extudates with an energy content of at least about 4,000 BTU per pound, preferably at least 5,000 BTU per pound, is blended with ground coal or coke and the blended material is then handled in a manner identical to that in which ground coal and coke are handled as fuels, i.e., pneumatically or mechanically charged to a zone of the kiln in which fuel is burned, preferably the firing zone. The blend preferably should have an energy content of at least about 8,000 BTU per pound.
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[00042] In another method sludge and waste crumb rubber mixtures are charged directly to a zone of the kiln in which fuel is burned, preferably the firing zone, without prior mixing or blending with another fuel. When charged to the kiln directly, the dewatered particulate material should have an energy content of at least 4,000 BTU per pound, preferably at least 5,000 BTU per pound, and most preferably greater than about 8,000 BTU per pound (4438 Cal per gram).
[00043] In another method sludge and waste crumb rubber mixtures are charged directly to a zone of the kiln in which fuel is burned, preferably the firing zone, without prior mixing or blending with another fuel. When charged to the kiln directly, the dewatered particulate material should have an energy content of at least 4,000 BTU per pound, preferably at least 5,000 BTU per pound, and most preferably greater than about 8,000 BTU per pound (4438 Cal per gram).
[00044] The present invention is primarily aimed at preparation of a fuel mixture by using refinery waste materials like sludge and spent waste crumb rubber, which are used for fuel applications mainly for burning in cement industries or brick industry or any other industry relevant to this. Sludge and waste crumb rubber mixtures of different experiments were made and those are illustrated as examples. The prepared sludge and waste crumb rubber mixtures were analyzed for metals; calorific values etc. mixtures are also tested for mechanical properties to assess the pellets strength.
[00045] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
EXAMPLE
EXAMPLE 1
[00046] In order to prepare best fuel mixture out of refinery waste material sludge and crumb rubber different mixtures were prepared. In the current embodiment sludge collected from refinery 10
tank and FCC waste crumb rubber were mixed in 1:1 ratio. In a typical experiment about 200 grams of sludge is mixed with 200 grams of crumb rubber are mixed in beaker using a spatula. After mixing the final material is loaded to laboratory extruder which has 4mm diameter die. Extruded material is dried at room temperature for four days. FIG. 3 illustrates an exemplary snippet depicting the solid fuel composition. The composition exhibited the calorific value of about 5541 Cal/gram, as illustrated in Table 1 below.
Table 1:
Sludge : crumb rubber
Calorific value, Cal/gram
1:1
5541
EXAMPLE 2
[00047] In the current embodiment sludge collected from refinery tank and waste crumb rubber were mixed in 2:1 ratio. In a typical experiment about 400 grams of sludge is mixed with 200 grams of waste crumb rubber mixed in beaker using a spatula. After mixing the final material is loaded to laboratory extruder which has 4mm diameter die. Extruded material is dried at room temperature for four days. The composition exhibited the calorific value of about 5900 Cal/gram, as illustrated in Table 2 below.
Table 2:
Sludge : crumb rubber
Calorific value, Cal/gram
2:1
5900
EXAMPLE 3
[00048] In the current embodiment sludge collected from refinery tank and waste crumb rubber were mixed in 3:1 ratio. In a typical experiment about 200 grams of sludge is mixed with 200 grams of waste crumb rubber mixed in beaker using a spatula. After mixing the final material is loaded to laboratory extruder which has 4mm diameter die. Extruded material is dried at room temperature for four days. The drying process may be enhanced by applying vacuum or heating at moderate temperatures. The composition exhibited the calorific value of about 6500 Cal/gram, as illustrated in Table 3 below.
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Table 3:
Sludge : crumb rubber
Calorific value, Cal/gram
3:1
6500
ADVANTAGES OF THE INVENTION
[00049] The present disclosure provides a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber.
[00050] The present disclosure provides a solid fuel composition including a pre-defined proportion of oil refinery sludge and waste crumb rubber with high calorific value.
[00051] The present disclosure provides a solid fuel composition that is economical to produce.
[00052] The present disclosure provides a solid fuel composition that effects disposal of waste and potentially hazardous materials.
[00053] The present disclosure provides a method of preparation of a solid fuel composition from waste and potentially hazardous materials.
[00054] The present disclosure provides a method of preparation of a solid fuel composition from waste and potentially hazardous materials that can find utility in rotary mineral processing kiln, such as a lime, light-weight aggregate, asphalt, cement kiln, brick industry and the likes.

We Claim:
1. A solid fuel composition comprising a pre-defined amount of oil refinery sludge and a pre-defined amount of crumb rubber, wherein said solid fuel composition exhibits calorific value of at least 5500 calories/gram.
2. The solid fuel composition as claimed in claim 1, wherein the oil refinery sludge is a landfill-prohibited solid hazardous refinery tank sludge, and wherein said refinery tank sludge comprises water in an amount ranging from about 10% to about 30% by weight of the sludge.
3. The solid fuel composition as claimed in claim 1, wherein the solid fuel composition is an extrudate comprising the pre-defined amount of oil refinery sludge and the pre-defined amount of crumb rubber.
4. The solid fuel composition as claimed in claim 1, wherein the solid fuel composition comprises oil refinery sludge and crumb rubber in a ratio ranging from about 1:1 to about 5:1.
5. The solid fuel composition as claimed in claim 1, wherein the solid fuel composition comprises oil refinery sludge and crumb rubber in a ratio of about 1:1, and wherein said solid fuel composition exhibits calorific value of about 5541 calories/gram.
6. The solid fuel composition as claimed in claim 1, wherein the solid fuel composition comprises oil refinery sludge and crumb rubber in a ratio of about 2:1, and wherein said solid fuel composition exhibits calorific value of about 5900 calories/gram.
7. The solid fuel composition as claimed in claim 1, wherein the solid fuel composition includes oil refinery sludge and crumb rubber in a ratio of about 3:1, and wherein said solid fuel composition exhibits calorific value of about 6500 calories/gram.
8. A method of preparation of a solid fuel composition, the method comprising the steps of:
mixing a pre-defined amount of oil refinery sludge and a pre-defined amount of crumb rubber to achieve a uniform mass therefrom; and
effecting extrusion of the uniform mass using an extruder to form a solid fuel composition,
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wherein said solid fuel composition exhibits calorific value of at least 5500 calories/gram.
9. The method as claimed in claim 8, wherein the method further comprises a step of mixing the solid fuel composition with any or a combination of a solid fuel and a liquid fuel.
10. The method as claimed in claim 8, wherein the oil refinery sludge is a landfill-prohibited solid hazardous refinery tank sludge, and wherein said refinery tank sludge comprises water in an amount ranging from about 10% to about 30% by weight of the sludge.
11. The method as claimed in claim 8, wherein the solid fuel composition is an extrudate comprising the pre-defined amount of oil refinery sludge and the pre-defined amount of crumb rubber.