The present invention refers generally to a composition of matter and, more specifically, to a petroleum substitute comprised of an organic solvent extract of an herbaceous plant biomass.
Hydrocarbons are the source of many fuels and chemical feedstocks used for industry and commerce in the world. Petroleum is the predominant source of these hydrocarbons. This petroleum is sourced from geological deposits located beneath the surface of the earth. These hydrocarbons are then refined and reformed and used as source chemicals for fuels and feedstocks. Traditionally these hydrocarbons are sourced from geological resources. However, hydrocarbons can be found in most living organisms. As hydrocarbons are produced by living organisms, these organisms can be cultivated and processed for use as source hydrocarbons. The ideal organisms for use as petroleum substitutes use energy from the sun to fully reduce carbon dioxide into source hydrocarbons.
Higher plants produce hydrocarbon compounds composed primarily of isoprenoids, which are organic compounds comprised of two or more hydrocarbon subunits each having five carbon atoms. These isoprenoids are often in the form of hydrocarbon terpenes made from pentene subunits primarily comprised of 2-methyl-2-butene as well as 2-methyl-1-butene. Most plants produce these isoprenoid terpenes in small amounts and utilize them to form more complex biochemicals. However, some types of plants produce terpenes as a major metabolic product. In particular, some members of the family Euphorbiaceae have very high levels of hydrocarbons present within their tissues.
A prominent example is Euphorbia tirucalli. This species contains particularly high levels of hydrocarbons having relatively low molecular weights. The hydrocarbons found in Euphorbia tirucalli plant material are mainly comprised of oligomerized pentenes formed from isoprene-derived pentene subunits 2-methyl-2-butene and 2-methyl-1-butene. These pentenes are then constructed via cellular metabolism into other chemicals such as hormones, energy stores, or defense chemicals.
Another isoprene-derived class of molecules is rubbers. Rubbers are diene polymers comprised of long poly-isoprene chains and can have a wide range of molecular weights depending on the number of isoprene monomers. Rubbers, however, typically contain many high molecular weight polymers made up of a large number of monomers. Some Euphorbiaceae plant species contain significant quantities of rubber. However, Euphorbia tirucalli plant material generally has a relatively low molecular weight group of oligomerized pentene metabolites, typically comprised of only a few monomers. Thus, Euphorbia tirucalli plant material has the potential for economical production of a petroleum substitute.
Attempts in the prior art to produce a petroleum substitute from plant material have focused on enzyme and pyrolysis-based methods for increasing hydrocarbon yields per unit biomass of plants having similar botanical and hydrocarbon-bearing characteristics as Euphorbia tirucalli. However, the prior art suffered from inefficiencies due to the energy costs required to achieve pyrolysis, the heat generated in the process, and the costs to derive the enzymes required for processing a biomass and extracting hydrocarbons. The prior art also suffered from inefficient and unpredictable yields of hydrocarbons from the raw biomass feedstocks. These early inventions existed in an environment of low oil prices coupled with less knowledge of plant agronomy and biochemistry. Today oil prices are much higher, making the benefit of these inventions per unit of biomass less economically attractive.
Accordingly, a need exists in the art for a petroleum substitute comprised of a hydrocarbon composition that can be produced from renewable plant-based sources in a simple and more economical manner than is currently achievable.
A preferred embodiment of the invention is directed generally to a petroleum substitute comprised of an organic solvent extract of an herbaceous hydrocarbon-bearing plant that can produce significant quantities of liquid terpenes. In a preferred embodiment, the plant species is Euphorbia tirucalli. Furthermore, in a preferred embodiment, the organic solvent used to extract hydrocarbons from the herbaceous plant material is a non-polar solvent. Preferably, the solvent is hexane. Once the hydrocarbons are extracted from a biomass of the plant material, the extracted hydrocarbons are separated from the solvent and can be used as a petroleum substitute or a feedstock for various petrochemical products. In addition, the resulting petroleum substitute product is compatible with existing means of distribution of liquid petroleum-based products. The extracted hydrocarbon composition may also be used to augment existing petroleum-based fuels.
The solvent extract of Euphorbia tirucalli is generally comprised of hydrocarbons having relatively low molecular weights. The hydrocarbons found in Euphorbia tirucalli plant material are mainly comprised of oligomerized pentenes formed from isoprene-derived pentene subunits 2-methyl-2-butene and 2-methyl-1-butene. Because most of the chemical compounds found in the extract are biologically synthesized from pentenes, the number of carbon atoms found in these chemicals is almost always a multiple of five, and commonly a multiple of ten. These relatively low molecular weight hydrocarbons have desirable properties for the petroleum industry. They can be utilized as plastic polymer precursors or in the production of gasoline additives. In addition, they can be directly distilled and utilized as a fuel or as a feedstock in the production of various petrochemical products.
The solvent extract of Euphorbia tirucalli is comprised of three fractions: a naphtha fraction, a grease fraction, and a tar fraction. The fraction having the lowest boiling point is the naphtha fraction. The naphtha fraction is comprised primarily of 2,6-dimethyl-2,6-octadiene and 2,7-dimethyl-2,6-octadiene, but also includes various monoterpenes (terpenes having ten carbon atoms) such as limonene, as well as other similar pentene oligomers. The naphtha fraction is the most abundant fraction of the solvent extract and also the most commercially important fraction. The naphtha fraction is a clear to pale yellow liquid having a high vapor pressure.
This fraction may include compounds having boiling points that can range from about 30 to 200 degrees Celsius. However, in most instances the majority of the liquids in the naphtha fraction have a boiling point in the range of about 150 to 180 degrees Celsius. In a preferred embodiment, the majority of the liquids in this fraction have a boiling point of about 170 to 180 degrees Celsius.
The second fraction is the grease fraction, which is a light to golden brown liquid comprised primarily of squalene with lesser concentrations of farnesene and phytane. The grease fraction will also include any diterpenes (terpenes having twenty carbon atoms) that may be present in the extract, as well as other similar pentene oligomers.
The final fraction, which has the highest boiling point, is the tar fraction. This fraction holds all of the solid and semi-solid hydrocarbons and is usually dark green due to the presence of chlorophyll. This fraction is comprised of rubbers, carotenes, chlorophyll, larger terpenoid molecules, and other similar pentene oligomers. Ketone groups are also present in this fraction in sterols as well as in the chlorophyll. However, the tar fraction contains little to no alcohols.
The solvent extract is prepared by first applying compressive and shearing forces to a raw biomass of Euphorbia tirucalli plant material. In a preferred embodiment, these forces are applied using a hammer mill, an array of rotating knives, and press rollers. The press rollers form a flat layer of plant material that is solvent permeable. A fibrous batt of Euphorbia tirucalli biomass is then prepared by stacking a plurality of layers on top of each other. Next, hydrocarbons are extracted from the biomass by conveying the fibrous batt in a direction that is countercurrent to a flow of hexane solvent in a continuous system. A mixture comprised of the hexane solvent and the extracted hydrocarbons is then recovered. Finally, the extracted hydrocarbons are separated from the solvent mixture to produce the organic solvent extract.
Accordingly, an object of the present invention is to provide a hydrocarbon composition comprised of an organic solvent extract of Euphorbia tirucalli plant material that can be used as a petroleum substitute or as a feedstock in the production of various petrochemicals. Another object of the present invention is to provide a hydrocarbon composition comprised of an organic solvent extract of Euphorbia tirucalli plant material that can be used to augment existing petroleum-based fuels. Yet another object of the present invention is to provide a petroleum substitute produced from renewable plant-based sources that are sufficiently high yielding in hydrocarbons to be economically viable. Furthermore, an object of the present invention is to provide a petroleum substitute that is compatible with existing means of distribution of liquid petroleum-based products.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
In the Summary above and in this Detailed Description, and the claims below, and in the accompanying drawings, reference is made to particular features, including method steps, of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with/or in the context of other particular aspects of the embodiments of the invention, and in the invention generally.
The term “comprises” and grammatical equivalents thereof are used herein to mean that other components, ingredients, steps, etc. are optionally present. For example, an article “comprising” components A, B, and C can contain only components A, B, and C, or can contain not only components A, B, and C, but also one or more other components.
Where reference is made herein to a method comprising two ore more defined steps, the defined steps can be carried out in any order or simultaneously (except where the context excludes that possibility), and the method can include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all the defined steps (except where the context excludes that possibility).
Turning now to the drawings,
The solvent extract of Euphorbia tirucalli is generally comprised of hydrocarbons having relatively low molecular weights. The hydrocarbons found in Euphorbia tirucalli plant material are mainly comprised of oligomerized pentenes. The subunits of these compounds are mostly comprised of 2-methyl-2-butene, 2-methyl-1-butene, and isoprene (2-methyl-1,3-butadiene), as illustrated in
The solvent extract of Euphorbia tirucalli is comprised of three fractions: a naphtha fraction, a grease fraction, and a tar fraction. The fraction having the lowest boiling point is the naphtha fraction. This fraction is typically comprised of compounds having ten carbon atoms, though there may be some compounds present in the fraction having five or fifteen carbon atoms. As illustrated in
The second fraction is the grease fraction, which is a light to golden brown liquid typically comprised of compounds having thirty carbon atoms, though this fraction may also contain compounds having 25 or 20 carbon atoms, with relatively small amounts of compounds having 15 carbon atoms. The grease fraction is primarily comprised of squalene with lesser concentrations of farnesene and phytane, as illustrated in
The final fraction, which has the highest boiling point, is the tar fraction. As illustrated in
As discussed above, the organic solvent extract comprising the three fractions is produced from herbaceous plant material.
The first step in the process, as illustrated in
In a preferred embodiment of the invention, the batt is produced by milling raw plant material in a three-step process. First, a hammer mill is used to compress the raw biomass of plant material and to reduce the particle size of the plant material. Next, an array of rotating knives, as illustrated in
The third step, as illustrated in
As illustrated in
The batt is comprised of a plurality of layers, and may be comprised of any number of layers. The number of layers used to construct a particular batt is determined by the desired volume of throughput in the solvent extraction phase.
Thus, the final product of this first series of steps is a fibrous, solvent-permeable batt comprised of a plurality of layers of plant fibers. The batt has generally uniform physical properties and can be produced in a continuous operation. The processed batt is then ready for use in the solvent extraction process.
As illustrated in
As illustrated in
In alternative embodiments, countercurrent flow between the batt and the solvent may be achieved by other means. For instance, pressurized flow and/or mechanical forces may be utilized to force countercurrent flow. However, gravity flow of the solvent is the preferred embodiment.
As illustrated in
As illustrated in
The batt is then conveyed out of the wash unit and enters a second wash unit where the solvent extraction process is repeated. This process may be repeated until the desired level of hydrocarbon oil extraction is achieved. Thus, the present invention may comprise any number of solvent wash units. The number of wash units utilized in a particular application would be selected based on the hydrocarbon content of the plant material, the throughput speed of the batt, and the number and types of different solvents utilized.
After the batt has been processed through all of the solvent wash units, it is then conveyed to a solvent recovery unit as illustrated in
The solvent recovery unit utilizes heat to evaporate a substantial portion of any remaining solvent from the processed batt until the batt is suitable for discharge. The batt is conveyed into an evaporator/boiler chamber, as illustrated in
As illustrated in
All of these streams of liquids and solubles are then subjected to a clarification and separation process, as illustrated in
Next, water and oil solubles are separated. In a preferred embodiment, separation is achieved via centrifugation. In another preferred embodiment, an array of multiple centrifuges is employed such that a continuous separation operation is utilized. The liquid stream to be centrifuged is comprised of two phases. The first phase is an organic or lipophilic phase comprising the solvent and the extracted hydrocarbon oils. The second phase is an aqueous or hydrophilic phase comprising the juice. Following the centrifugation process, the two phases are separated into two streams, and the organic stream is further processed in a distillation unit.
As illustrated in
The solution of hydrocarbons enters the distillation unit and is heated. In a preferred embodiment where the solvent is hexane, the solution is heated to a temperature of about 70 to 80 degrees Celsius at approximately atmospheric pressure. Under these conditions, the hexane solvent will boil while the extracted hydrocarbons will remain in a liquid state. The hexane vapors are then condensed and reused in the solvent extraction process. If a different solvent is employed, the operating temperature and pressure of the unit may be changed in order to optimize separation.
This unit is a simple distillation/evaporation unit that only separates the solvent from the heavier extracted hydrocarbons, which is the final product. If desired, the extracted hydrocarbons may then be further refined and processed in a fractional distillation unit in order to separate the solution of extracted hydrocarbons into its constituent fractions.
It is understood that versions of the invention may come in different forms and embodiments. Additionally, it is understood that one of skill in the art would appreciate these various forms and embodiments as falling within the scope of the invention as disclosed herein.
The present application is a divisional of prior application Ser. No. 12/931,433, filed Feb. 1, 2011, currently pending. This prior application is incorporated herein by reference, including the specification.
Number | Date | Country | |
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Parent | 12931433 | Feb 2011 | US |
Child | 14510519 | US |