WO2010042590A1

WO2010042590A1 - Alternative fuel comprising solids and by-products or waste material from industrial processes

Info

Publication number: WO2010042590A1
Application number: PCT/US2009/059802
Authority: WO
Inventors: Bo L. Tran
Original assignee: Nalco Company
Priority date: 2008-10-07
Filing date: 2009-10-07
Publication date: 2010-04-15
Also published as: US20090025276A1

Abstract

The invention provides an alternative fuel composition and methods of preparing and using the composition. The alternative fuel can comprise coal, or another combustible solid, and one or more components selected from a group consisting of sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, crude glycerin by-product and fatty acids.

Description

ALTERNATIVE FUEL COMPRISING SOLIDS AND BY-PRODUCTS OR WASTE MATERIAL FROM INDUSTRIAL PROCESSES

Cross-Reference to Related Applications This application is a continuation in part application claiming priority from currently co-pending application number 11/561,150 which was filed on November 17, 2006. Statement Regarding Federally Sponsored Research or Development

Not Applicable. Background of the Invention This invention relates to alternative fuels comprising by-products or waste material from industrial processes and methods of using the fuels. More particularly, this invention concerns alternative fuels comprising liquid hydrocarbons derived from biomass and combustible solids. The biomass liquid hydrocarbons can include sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, crude glycerin by- product and fatty acids. The liquid hydrocarbon is mixed with coal or other combustible solids to prepare the alternative fuel.

The current US economy is dominated by technologies that rely on fossil energy (coal, petroleum, and natural gas) to produce fuels. Biomass presents a promising renewable energy source that could provide an alternative to the use of fossil resources. Biomass includes crops, trees, grasses, crop residues, forest residues, animal wastes, and mum^'cipal wastes. There are many reasons to increase the use biomass for energy, including lessening dependence upon foreign oil, utilizing green chemistries from a renewable source, creating less toxic pollution, and improving the domestic agricultural economy.

A fuel product formed from vegetable oil and dried cellulosic powder is disclosed in U.S. Pat. No. 6,818,027 B2 and Published Patent Application No. 2005/0055873 Al. A fuel product formed by homogenizing, heating, pressurizing and removing water from organic waste products of industrial processes and then separating a selected constituent from the product into a waste stream and blending the waste stream with a fuel is disclosed in Published Patent Application Publication No. 2005/0142250 Al.

U.S. Pat. No. 6,890,451 B2 discloses an anti-icing or deicing fluid comprising by- products of triglyceride processing and its application to surfaces including particulate materials such as coal. A method of preventing the agglomeration of coal in subfreezing temperatures comprising applying an anti-agglomerating amount of by-product glycerin containing up to 5 percent methanol by weight to the coal is disclosed in U.S. Pat. No. 7,108,800. A method of preventing the agglomeration of coal in subfreezing temperatures comprising applying an anti- agglomerating amount of by-product sugar solution to the coal is disclosed in U.S. Pat. No. 6,878,308 B2. Brief Summary of the Invention

At least one embodiment of the invention is directed towards a novel and cost effective fuel and methods of preparing and using the fuel. The fuel comprises biomass liquid hydrocarbons mixed or blended with existing fuels such as coal and/or other combustible solids. Some of the biomass hydrocarbon liquids of this invention are by-products of current processes. For example, fatty acids and crude glycerin are by-products of a biodiesel manufacturing process.

Accordingly, in an embodiment, this invention is an alternative fuel comprising one or more combustible solids and one or more liquid hydrocarbon components selected from a group consisting of sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, crude glycerin by-product and fatty acids, provided that when the liquid hydrocarbon component is vegetable oil, the combustible solid is other than a cellulosic powder and further provided that when the combustible solid is coal, the liquid hydrocarbon component Is other than sugar solutions.

At least one embodiment is directed towards a method of preparing a alternative fuel comprising applying one or more liquid hydrocarbon components selected from a group consisting of sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, crude glycerin by-product and fatty acids to one or more combustible solids, provided that when the liquid hydrocarbon component is vegetable oil, the combustible solid is other than a cellulosic powder and further provided that when the combustible solid is coal, the liquid hydrocarbon component is other than sugar solutions. Detailed Description of the Invention The invention uses biomass liquids such as sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, glycerin and fatty acids mixed with coal or other combustible solids to create alternative fuels. The sugar solutions, vegetable oils, animal fats, triglycerides, methyl esters, crude glycerin by-product and fatty acids described herein are "green", i.e. non-hazardous, non-toxic, biodegradable, environmentally friendly, and/or derived from renewable sources. For purposes of this application the definition of certain terms used herein is as follows:

The definition of "combustible solids" is any solid combustible material which can be mixed with one or more biomass liquids as described herein to prepare the alternative fuel of the invention. In at least one embodiment, the combustible solid is selected from coal, wood chips, coke, and garbage, hi at least one embodiment, the combustible solid is coal. "Coal" includes fine coal from stockpiles, fine coal from impoundments, run of mine coal washed, run of mine coal unwashed and waste coal. Coke is derived from coal. Garbage includes municipal and/or industrial garbage. In at least one embodiment, the combustible solid is fatty acid byproduct. The definition of "Sugar solutions" is by-products of sugar beet or sugar cane processing which can comprise one or more components selected from raffinose, glutamine, betaine, lactate, glucose and/or fructose. Other components can include sodium, potassium, chloride, nitrate, nitrite, acetate, ammonia and magnesium. The by-products are also commonly referred to as "de-sugared" solutions.

The definition of "black liquor" is the liquor resulting from the sulfate or kraft paper processes. Black liquor comprises lignin and tall oil.

The definition of "tall oil" is a mixture of rosin acids, fatty acids including oleic and linoleic acids and other organic material including sterols and long chain alcohols resulting from acid treatment of black liquor as described above.

The definition of "triglycerides" is esters of glycerol, a trihydric alcohol, with different fatty acids of varying molecular weight associated with a particular fat or oil. Triglycerides are the principal components of animal fats and vegetable oils. The most common fatty acids sourced from natural fats and oils include palmitic, stearic and linoleic acid. The definition of "fatty acids" is carboxylic acids derived from or contained in an animal or vegetable fat or oil. Fatty acids comprise a terminal COOH group and a long chain saturated or unsaturated alkyl chain. Representative fatty acids include butyric acid, lauric acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and the like.

The definition of "crude glycerin by-product" and "fatty acids by-products" are by- product derivatives from transesterification reactions involving triglycerides including transesterification reactions involving biodiesel manufacturing processes as described herein. Both "crude glycerin by-product" and "fatty acids by-products" comprise more than one component selected from the list consisting of: fatty acids, esters, glycerin, salt, methanol, tocopherol, sterol, mono-glycerides, di-glycerides, and triglycerides. The definition of "methyl esters" and "ethyl esters" is methyl and ethyl esters of fatty acids as described herein.

The definition of "vegetable oil" is triglycerides extracted from the seeds, fruit or leaves of plants including corn oil, soybean oil, canola oil, palm oil, coconut oil, rapeseed oil, algae, and the like.

In at least one embodiment, methyl esters, ethyl esters, crude glycerin by-product and fatty acids are derived from transesterification reactions involving triglycerides.

Transesterification reactions involving triglycerides" refers to the splitting of triglyceride esters derived from vegetable oils and/or animal fats in the presence of base and a monohydroxy alcohol such as methanol or ethanol to produce monoesters of the fatty acids comprising the original triglycerides.

Representative fats and oils used in the transesterification reactions described herein include tallow, crude tall oil, virgin vegetable oils, soy, mustard, canola, coconut, rapeseed, palm, algae, poultry offal, fish oils, used cooking oils, and/or trap grease, and the like. In at least one embodiment, the crude glycerin by-product, fatty acids, ethyl esters and methyl esters are derived from a biodiesel manufacturing process.

Biodiesel is a cleaner-burning diesel replacement fuel made from natural, renewable sources. For example, biodiesel can include fatty acid alkyl esters used as a cleaner- burning diesel replacement fuel made from sources such as new and used vegetable oils and animal fats.

According to the American Fuel Data Center of the U.S. Department of Energy, approximately 55% of the biodiesel is currently produced from recycled fat or oil feedstock, including recycled cooking grease. The other half of the industry is limited to vegetable oils, the least expensive of which is soy oil. The soy industry has been the driving force behind biodiesel commercialization because of excess production capacity, product surpluses, and declining prices. Similar issues apply to the recycled grease and animal fats industry, even though these feedstocks are less expensive than soy oils. Based on the combined resources of both industries, there is enough of the feedstock to supply 1.9 billion gallons of biodiesel. Biodiesel is typically made through a chemical process called transesterification in which vegetable oil or animal fats are converted to fatty acid alkyl esters and crude glycerin byproduct. Patty acids and fatty acid alkyl esters can be produced from oils and fats by base- catalyzed transesterification of the oil, direct acid-catalyzed esterifάcation of the oil and conversion of the oil to fatty acids and subsequent esterification to biodiesel. The majority of fatty acid alkyl esters are produced by the base-catalyzed method.

In general, any base may be used as the catalyst used for transesterification of the oil to produce biodiesel, however sodium hydroxide or potassium hydroxide are used in most commercial processes. hi the biodiesel manufacturing process, the oils and fats can be filtered and preprocessed to remove water and contaminants. If free fatty acids are present, they can be removed or transformed into biodiesel using special pretreatment technologies, such as acid catalyzed esterification. The pretreated oils and fats can then be mixed with an alcohol and a catalyst (e.g. base). The base used for the reaction is typically sodium hydroxide or potassium hydroxide, being dissolved in the alcohol used (typically ethanol or methanol) to form the corresponding alkoxide, with standard agitation or mixing. It should be appreciated that any suitable base can be used. The alkoxide may then be charged into a closed reaction vessel and the oils and fats are added. The system can then be closed, and held at about 71. degree. C. (16O.degree. F.) for a period of about 1 to 8 hours, although some systems recommend that the reactions take place at room temperature. Once the reactions are complete the oil molecules (e.g. triglycerides) are hydrolyzed and two major products are produced: 1) a crude fatty acid alkyl esters phase (i.e. biodiesel phase) and 2) a crude glycerin by-product phase. Typically, the crude fatty acid alkyl ester phase forms a layer on top of the denser crude glycerin by-product phase. Because the crude glycerin by-product phase is denser than the biodiesel phase, the two can be gravity separated. For example, the crude glycerin by-product phase can be simply drawn off the bottom of a settling vessel. Li some cases, a centrifuge may be employed to speed the separation of the two phases.

The crude glycerin by-product phase typically consists of a mixture of glycerin, methyl esters, methanol, mong and inorganic salts and water. Mong is "matiere organique non glycerol". Mong normally consists of soaps, free fatty acids, and other impurities. Methyl esters are typically present in an amount of about 0.01 to about 5 percent by weight.

Methanol can be present in the crude glycerin by-product and fatty acids in an amount greater than about 5 weight percent to about 30 weight percent. The methanol can be a valuable component in the alternative fuels because of its low flash point which can help ignite the fuel.

In certain instances, it may be necessary to further refine the crude glycerin byproduct prior to use, for example by washing, acidulation or distillation to adjust the glycerin concentration and/or remove impurities. Methanol may also be added to the desired concentration.

In at least one embodiment, the crude glycerin-containing by-product comprises about 30 to about 95 weight percent of glycerin.

In at least one embodiment, the combustible solid is coal and the liquid hydrocarbon component is crude glycerin by-product. In at least one embodiment, the combustible solid is fatty acid by-product and the liquid hydrocarbon is crude glycerin by-product.

In at least one embodiment, the alternative fuel comprises one or more solid fatty acids by-product and a crude glycerin by-product. This alternative fuel can be heated to facilitate fiowability and allow for its injection into furnaces.

The fatty acid by-products can originate from the refining of the crude fatty acid alkyl esters phase and/or the crude glycerin by-product phase during the biodiesel manufacturing process. For example, the crude fatty acid alkyl esters phase typically includes a mixture of fatty acid alkyl esters, water and a fatty acid salts component. These fatty acid salts component generally form a solution with the water phase (e.g. soap water) where they can be further separated from the fatty acid alkyl esters component. Once separated from the fatty acid alkyl esters component, any suitable acid such as, for example, hydrochloric acid can be added to the water phase containing the fatty acid salts component to produce the fatty acid by-products of the present invention. The fatty acid by-product may be in a wax or solid form. It can also contain fatty acid esters and crude glycerin by-product. The esters are beneficial components in the alternative fuel mixture. To ease handling and application of the wax or solid form, the solid fatty acid byproduct can be heated to about 120 degrees F or higher which enhances its fiowability.

Similarly, the crude glycerin by-product phase typically includes a mixture of glycerin, water and a fatty acid salts component. This fatty acid salts component forms a solution or suspension with the water phase where it can be further separated from the glycerin component by adding any suitable acid to recover the fatty acid by-products suitable for the present invention.

It should be appreciated that the fatty acid by-products of the present invention can be derived from the acidulation of any of the biodiesel manufacturing process streams/stages that contain the fatty acid salts component (e.g. soap water) including, for example, the wash water. These fatty acid by-products derived from any of the different stages/streams of the biodiesel manufacturing process can be used as a component in alternative fuel.

The alternative fuels are prepared by applying the desired amount of liquid hydrocarbon component to the combustible solid, for example by spraying onto piles of the combustible solid or by means of showers oriented over conveyors used to transport the combustible solid. If desired, the liquid hydrocarbon component-combustible solid mixture may be mixed to ensure even distribution of the liquid hydrocarbon in the combustible solid.

In the case of loose or finely divided combustible solids, the alternative fuel may be prepared by applying the liquid hydrocarbon component to the combustible solid and pressing the resulting material into briquettes or ingots.

In at least one embodiment, about 0.1 to about 49 weight percent of said liquid hydrocarbon component is applied to the combustible solid. hi at least one embodiment, about 0.1 to about 25 weight percent of said liquid hydrocarbon component is applied to the combustible solid.

The alternative fuel of this invention may be used as a substitute for, or additive to conventional combustible solids for combustion in boilers or furnaces. Changes can be made in the composition, operation, and arrangement of the method of the invention described herein without departing from the concept and scope of the invention as defined in the claims. While this invention may be embodied in many different forms, there are shown and described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. Furthermore, the invention encompasses any possible combination of some or all of the various embodiments described herein. All patents or published patent applications cited or otherwise mentioned in this application are hereby incorporated by reference in their entirety herein. The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term "comprising" means "including, but not limited to". Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto.

Claims

1. An alternative fuel comprising one or more combustible solids and one or more liquid hydrocarbon components selected from a group consisting of sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, crude glycerin by- product and fatty acids, provided that when the liquid hydrocarbon component is vegetable oil, the combustible solid is other than a cellulosic powder and further provided that when the combustible solid is coal, the liquid hydrocarbon component is other than sugar solutions.

2. The alternative fuel of claim 1 comprising about 0.1 to about 49 weight percent of said liquid hydrocarbon components.

3. The alternative fuel of claim 1 wherein the combustible solid is selected from coal, wood chips, coke, and garbage.

4. The alternative fuel of claim 3 comprising about 0.1 to about 25 weight percent of said liquid hydrocarbon components.

5. The alternative fuel of claim 3 wherein the methyl esters, ethyl esters, crude glycerin by- product and fatty acids are derived from transesterification reactions involving triglycerides.

6. The alternative fuel of claim 3 wherein the methyl esters, ethyl esters, crude glycerin byproduct and fatty acids are derived from a biodiesel manufacturing process.

7. The alternative fuel of claim 3 wherein the combustible solid is coal.

8. The alternative fuel of claim 3 wherein the liquid hydrocarbon is a crude glycerin by- product of the biodiesel process comprising about 5 to about 30 weight percent methanol and the crude glycerin by-product comprises about 30 to about 95 weight percent of glycerin.

9. The alternative fuel of claim 1 wherein the combustible solid is fatty acid by-product.

10. The alternative fuel of claim 9 wherein the solid alternative fuel is heated to increase flowability.

11. A method of preparing an alternative fuel comprising applying one or more liquid hydrocarbon components selected from a group consisting of sugar solutions, tall oil, black liquor, vegetable oils, animal fats, triglycerides, methyl esters, ethyl esters, crude glycerin byproduct and fatty acids to one or more combustible solids, provided that when the liquid hydrocarbon component is vegetable oil, the combustible solid is other than a cellulosic powder and further provided that when the combustible solid is coal, the liquid hydrocarbon component is other than sugar solutions.

12. The method of claim 11 wherein about 0.1 to about 49 weight percent of said liquid hydrocarbon components is applied to said combustible solids.

13. The method of claim 12 wherein the combustible solids are selected from coal, wood chips, coke and garbage.

14. The method of claim 13 wherein about 0.1 to about 25 weight percent of said liquid hydrocarbon components are applied to said combustible solids.

15. The method of claim 12 wherein the combustible solid is coal and the liquid hydrocarbon is a crude glycerin by-product of the biodiesel process comprising between about 5 and about 30 weight percent methanol.