Patent Publication Number: US-2019185774-A1

Title: Fuels and ignition aids made of modified, renewable raw materials

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application (under 35 USC § 371) of PCT/EP2017/071074, filed Aug. 22, 2017, which claims benefit of German application No. 10 2016 115 664.7, filed Aug. 24, 2016, the contents of each of which are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Technical Field and State of the Art 
     The present invention relates to fuels and ignition aids made of renewable raw materials and/or organic recycling or waste materials which are provided with various additives aimed at improving their properties. Moreover, the invention relates to the use of fats and oils stemming from cascade or secondary utilization in order to produce such fuels and ignition aids as well as special types or commercial forms of these fuels and ignition aids. 
     Not least from the standpoint of climate protection, there is a need to greatly reduce the consumption of fossil fuels such as, for instance, petroleum, coal and gas, in order to generate power. For this reason, fuels from renewable organic raw materials are acquiring ever-greater significance. In this context, examples include straw, wood as well as paper and cardboard that are made mainly of these raw materials. 
     The state of the art puts forward numerous proposals for improving the combustion properties, increasing the heating value and reducing the slag formation associated with these fuels. For instance, German patent application DE 10 2004 042 659 A1 discloses a fuel pellet made of primary waste and recycling material obtained from grain harvesting and grain processing, to which lime is admixed in order to reduce slag formation. 
     German utility model DE 20 2006 014 651 U1 describes a fuel which contains natural organic oils and fats as well as sodium perborate in order to increase the heating value and to reduce slag formation. 
     German utility model DE 08212935 U1 relates to fuel briquettes consisting of a mixture of rubber particles, wood shavings and paper scraps held together by means of a cellulose adhesive. In this process, the particles containing cellulose are impregnated with oil or waste oil. 
     Fuel briquettes which are made on the basis of wood and whose production on a briquetting machine involves the admixture of oily vegetable matter as the binding agent and needles or leaves as the fragrance additive are proposed in German patent application DE 196 31 762 A1. 
     German utility models DE 20 15 005 372 U1 and DE 20 2016 102 694 U1 relate to ignition aids which consist of dried pine cones and spruce cones that are combined with cardboard or paper and a combustible fat, or in which the fuel element is made of a cotton wool-like cellular material that has been impregnated with wax. 
     In view of the current and increasing scarcity of raw materials, it is necessary to develop new processing modalities, application areas and re-utilization possibilities for waste materials so that these can be re-used while entailing the lowest possible losses in quality. The trend reversal observed in all realms of society, namely, the realization that waste materials stemming from primary application areas should be considered as re-useable materials that can be returned to the economic cycle is based not only on environmental considerations but also to an increasing extent on economic and financial interests. 
     For example, European patent specification EP 2 109 660 B1 describes a method for the production of starting materials or additives for cosmetics, pharmaceuticals and/or combustion materials or fuels for heating systems or internal combustion engines as well as for candles or thermal storage materials. In this process, contaminated materials classified as C1, C2 or C3 under EU Regulation 1774/2002 or EU Regulation 1069/2009 are processed for the purpose according to the invention specified there. 
     In the case of the combustible materials known from the state of the art, their ignition or combustion properties are modified with petrochemical substances or with basic materials stemming from primary production such as fats and oils preferably consisting of palm oil or rapeseed oil, whereby these substances are then no longer available for their actual intended purpose. The suggested use of secondary materials in the form of waste oil and rubber particles is likewise unsuitable for heating and combustion purposes since this is associated with unacceptable environmental pollution in the form of toxic substances. Finally, when it comes to combustible products from the state of the art, their handling and portioning properties are often very limited, which detrimentally affects their use in various cases. 
     International patent application WO 2012/068 640 A1 discloses a fuel for CO combustion with coal in a coal-burning power plant entailing low CO 2  emissions, having a certain percentage of waste oil and a percentage of cellulose material that serves to absorb the waste oil. This waste oil can consist of recycling materials or waste materials from various sources. 
     European patent application EP 1 600 493 A2 discloses the packaging of wood or of materials containing wood in a bag or pouch made of linen in order to make them easier to use and to ignite. In addition, this bag or pouch is impregnated with an oil. The oil that is used is high-grade natural or vegetable oils, which can also be perfumed. 
     Before this backdrop, the present invention was based on an objective of putting forward fuels and the like that, if at all possible, are made completely of sustainable and regionally available raw materials. In this context, when it comes to the use according to preferred embodiments of the invention, these raw materials should not compete with another use, for instance, as components of the food chain. After all, an objective of the present invention was to put forward fuels and the like which, in spite of the above-mentioned boundary conditions, display excellent ignition and combustion properties while also allowing the simplest handling possible. 
     This objective is achieved by the present invention as described below. 
     SUMMARY OF THE INVENTION 
     A fuel is formed by combining one or more oils or fats sourced from waste and recycling materials stemming from secondary or cascade utilization that have been hydrogenated with a cellulose or hemicellulose or mixture of cellulose and hemicellulose. The waste and recycling materials may be used cooking fats, returns and reject batches stemming from the food and cosmetics industries, used vegetable oils, animal fats from slaughterhouse waste, and mixtures thereof. Besides hydrogenation, other chemical and/or physical processing may be done on the waste and recycling materials, such as liquefying, filtering, enriching, and purifying, such as by distillation. The material containing cellulose or hemicellulose may comprise wood residues, or waste and recycling matter from grasses ( Poaceae ), or waste and recycling matter from sedges ( Cyperaceae ), or grain cultivation or grain processing, and mixtures thereof. The cellulose or hemicellulose materials may be admixed with the hydrogenated waste and recycling materials, such as by spraying or immersing or otherwise being mixed therewith, to form the fuel. 
    
    
     DETAILED DESCRIPTION 
     The raw materials (raw materials A) for the fuels and ignition aids according to the invention (also together referred to as fuels) are, on the one hand, substances stemming from secondary or cascade utilization (waste and recycling materials which can be readily burned as such without releasing environmentally harmful substances in this process. These are preferably cellulose or hemicellulose substances. Preferred examples are wood or wood residues in the form of sawdust, shavings, fibers, small pieces or wood dust, which can also be compressed and mixed together with each other. Likewise included here are paper and cardboard of any grade as well as waste and recycling materials stemming from grain cultivation and grain processing such as, for instance, chaff, threshing waste, chips, dust, flour and straw. In this context, the term “straw” is used as a collective term for threshed and/or dried stalks and leaves of plants, protists of any type and size such as, for example, grains, oily plants, fibrous plants, legumes, etc. According to the invention, these are preferably plants that grow annually and thus especially meet the requirement of sustainability. According to the invention, straw is also used in the form of (twisted) straw ropes. 
     The list of raw materials A presented above is not complete and any person skilled in the art who has knowledge of the present invention can directly augment this list with additional substances and materials that are suitable for the purpose according to the invention. 
     The above-mentioned materials are characterized by a high energy yield when they are burned, but they need to be improved in terms of their ignition and combustion behavior as well as ease of handling. 
     These raw materials A are improved or modified according to the invention with an eye towards the above-mentioned criteria by the addition of oils and fats or their derivatives or constituents such as fatty acids, fatty alcohols, glycerin from the secondary sector or from cascade utilization. These fats and oils are constituents of, or themselves constitute, waste or recycling materials from cascade or secondary utilization and normally have to be disposed of at great effort or collected for further utilization (raw materials B). For the objectives of the present invention, the term “cascade utilization” refers to the preceding single or multiple use of a substance or material in identical or different applications. 
     However, as a rule, it is not possible to directly make use according to the invention of the raw materials B since undefined substance mixtures are obtained from the waste sector of secondary or cascade utilization (e.g. used cooking fats, returns and reject batches from the food and cosmetics industries, heavily contaminated C1 to C3 materials that fall under EU Regulation 1774/2002 or EU Regulation (EC) 1069/2009, used vegetable oils and animal fats from slaughterhouse waste as well as fats and oil from the animal-feed sector such as fish and crustacean oils, corn oil, olive oil, cotton-seed oil, soy oil, coconut oil, palm oil, sunflower oil and rapeseed oil). Moreover, the heat changes brought about by the processing give rise to polymerization products and/or breakdown products. Aside from the undefined chemical composition, it is also often the case that the physical parameters such as, for instance, an excessively low melting point of such substance mixtures stand in the way of their use according to the invention. If the melting point of the oil and fat component is too low, this makes processing, handling and storage of the thus-produced fuels all the more difficult, especially at high temperatures. 
     For this reason, the waste and recycling materials that can be used according to the invention and that stem from secondary or cascade utilization have to be processed prior to their being used. For this purpose, preferably the following method steps are suitable which are preferably all carried out in the indicated sequence. Depending on the condition and the quality of the available fat and oil component, it is also possible to dispense with one or more individual steps. 
     The material on hand from secondary or cascade utilization is liquefied and optionally fed through a filter system in order to eliminate any foreign matter present. 
     In a mixing reactor, the desired fat and oil materials are enriched by means of sorption (media: zeolites, activated carbon, saw shavings, etc.) at a phase boundary and washed for a time period of preferably 15 to 45 minutes until the possibly acidic washing water is completely clear. The temperature during this procedure—which sometimes has to be repeated one or more times—is preferably approximately 70° C. to 80° C. 
     This is usually followed by another filtration step. During this step, the filter medium (e.g. zeolites) is preferably configured in such a way that ranges of up to 1.2 μm can be filtered and a lipid permeability is achieved and maintained. The product of this filtration can, if necessary, undergo step 2 once again, whereby in this case, this is carried out at temperatures of preferably 50° C. to 110° C. 
     The product of the preceding method steps can undergo distillation in order to perform further (fine) purification. For instance, in this manner, it is possible to separate out undesired olfactory contamination. Preferably, the distillation is carried out up to an acid value of less than 2. This allows the further use according to the invention of highly broken-down substances stemming from second or third utilization. Incremental inspection and sampling are advisable in this context. 
     Optionally, this can be followed by a hydrogenation step. This is described extensively, for example, in European patent specification EP 2 109 660 B1 and serves, on the one hand, to reliably decontaminate the employed raw materials B, eliminating bacteria, fungi, viruses, etc. (e.g. in the case of C1 to C3 materials) and, on the other hand, this step serves to achieve fat hydrogenation by saturating the double bonds as well as to obtain an end product that is as homogeneous as possible. This process is preferably carried out at 200° C. to 280° C. and at pressures of 0.2 MPa to 5 MPa. Sampling and determining the iodine value (preferably, e.g. 1 to 120) make it possible to regulate the desired degree of hydrogenation. In the realm of the fuels that are to be produced here, splitting the double bonds has proven to be advantageous in order to prevent spontaneous self-ignition processes, without thereby detrimentally affecting a quick burn-off and clean combustion processes. 
     A subsequent filtration process can be advantageous for purposes of removing any residues of the common hydrogenation catalysts and any undesired polymerization products that might be present. 
     The product thus obtained is filled into a thermal storage unit, preferably at temperatures from 25° C. to 100° C. and then stored. As a rule, an excessively short cooling time with high temperature gradients should be avoided for the processed raw materials B since this can lead to unstable crystal structures which could have a detrimental effect on the properties of the fuel end products. 
     The explained method steps 1 to 7 are fundamentally known in the state of the art. Their configuration and sequence can be easily adapted to the starting materials in question (raw materials B) by the person skilled in the art. 
     The processed raw materials B thus obtained preferably have melting points within the range from 30° C. to 60° C. 
     For the purposes of the invention, the various (processed) raw materials B can be fundamentally mixed and used in any desired ratio in order to process them as well as afterwards. With an eye towards further improving the properties, in certain cases, it can be advisable to admix small amounts of primary fats and primary oils to the purified material. 
     The raw materials B processed according to the invention exhibit a purity and quality that allow their safe use in an array of industrially as well as non-industrially manufactured products. After appropriate processing, they can also be employed in the food and animal-feed sectors. Examples of these are glycerin or substances containing glycerin stemming from cascade utilization, whereby the glycerin can be re-used after the described treatment, for example, in the food industry, as solvents and humectants for tobacco and cosmetics and also as an ingredient of anti-freeze agents and lubricants. Moreover, the fats, fatty acids and fatty alcohols thus obtained are suitable, for example, as fuel for combustion machines. 
     For the production of the fuel according to the invention, the processed raw materials B are admixed to the raw materials A. There are fundamentally no limitations when it comes to the possible combinations of the raw materials A and the processed raw materials B (both in terms of the composition of the raw materials A and of the processed raw materials B as well as in terms of the composition of the combination of A and processed B). Preference is given to A-to-B ratios within the range from 90:10 to 10:90, especially of approximately 50:50 (all figures are in % by weight). In this context, the raw materials A can have been pretreated. This means that these materials can be present in mixed or compressed form as pellets or granules, or else twisted into a kind of rope, for instance, in the case of fibers and straw, in order to increase the energy density. The raw materials A are preferably coated with the processed raw materials B, sprayed with the processed raw materials B or else immersed into the processed raw materials B. The raw materials A and the processed raw materials B can also be mixed together and, if applicable, can be subsequently compressed to form pellets or granules. There are no restrictions whatsoever regarding the way in which the raw materials A are mixed with the processed raw materials B. This procedure can be adapted to the materials in question and to the application purposes in the best possible manner. The (requisite) degree of processing of the raw materials B can also vary to a great extent. This ranges from no need for any processing all the way to a complete deployment of all of the method steps described. According to the invention, this is all encompassed by the terms “processing” or “processed”. 
     The fuels manufactured according to the invention can be produced and offered in a wide array of types, for instance, as rope pieces, in the form of briquettes, slabs, cubes, sticks, pellets, granules and as dusts of various grain sizes. Packaging the fuels according to the invention has proven to be very advantageous when it comes to their handling and portioning properties, especially for their use as ignition aids such as, for example, grill lighters and lighters for fireplaces or ceramic heating stoves. In this context, preference is given to packaging in pouches or bags of various sizes which can be described as small, large or extra large teabags. These, in turn, can be packaged in other packaging units (for instance, boxes or crates). 
     These bags are filled with the raw materials A—which can already but do not necessarily have to have been combined with the processed raw materials B. Suitable for this purpose are especially small-sized or fine-grained raw materials A such as, for example, dusts. The bags thus filled are subsequently sprayed or coated with the processed raw materials B or else immersed into the processed raw materials B, so that a fat or oil coating is formed on them. This coating protects the bag and its contents against moisture, so that this kindling material can be ignited, for example, during barbecuing, even when it is raining, and it then reliably burns off. Moreover, this also reduces saturation with humidity during storage and ensures reliable ignition and burn-off behavior. In addition, the raw materials A can be mixed in a mixing drum together with, for instance, fat granules and subsequently, this mixture can be filled into the bag by means of a filling station (teabag filling system). Various materials such as, for example, absorbent paper, filter paper, cellulose, etc. are all well-suited as the wall material of the bags or pouches. 
     Finally, fragrances and colorants (e.g. cedar oil) and/or other admixtures such as, for instance, pyrotechnical agents to generate light effects (for example, Cu powder) can be admixed to the fuels according to the invention. In this context, usually an amount of 2% to 3% by weight relative to the total fuel should not be exceeded. In most cases, considerably smaller amounts are already sufficient in order to attain the desired olfactory and visual effects. 
     The fuels according to the invention are characterized by a reliable ignition and burn-off behavior as well as convenient handling and portioning properties. An aspect worth mentioning is the sustainability of these fuels since they can be made exclusively out of recycling or waste materials which, furthermore, are regionally available in sufficient quantities and consequently do not have to be transported over long distances. These fuels or kindling materials are also provided with a hydrophobic finish, a measure which significantly delays their degradation processes and reduces or prevents the release of carbon oxides. The release of carbon monoxide, for example, in storage units or containers holding untreated wood pellets, is a problem that should not be underestimated. 
     The present invention is not restricted in terms of its configuration to the embodiments presented here. Rather, several variants are conceivable which make use of the solution presented here, even in the case of other types of configurations. It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this disclosure is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present disclosure as defined by the appended claims.