Flax Based Fuel Pellet and Method of Manufacture

Abstract

A fuel pellet made substantially of flax stem fiber. The fuel pellet is made from waste material available at minimal cost that produces pellets that burn at a high temperature, generate little smoke and less than about 4% ash residue, and can be stored for long periods without deteriorating. Preferred fuel pellets include at least about 60% flax stem fiber; wherein at least about 60% of the particles are less than about a quarter of an inch in length. The fuel pellet is processed by first selecting or processing the flax stem fiber so that it has a moisture content of from about 5 to about 12%. The bulk flax stem fiber material is then processed in a hammermill or the like to reduce the size of the fiber particles. The processed flax is then extruded through a commercial pelletizing machine. The pellets are then cut and then dried.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to fuel pellets. Particularly, the present invention relates to a fuel pellet containing flax stem fibers in combination with a binder, preferably, vegetable oils or oilseeds, for use as an alternative heating source for pellet type residential and commercial heating appliances such as pellet stoves, pellet boilers, pellet furnaces, stoker type heating systems, furnaces, heating appliances and the like.[0003]2. Description of the Related Art[0004]In recent years, pellet burning heating appliances have increased in popularity. Such appliances generate heat for homes by burning small relatively solid pellets which are fed to the fire chamber at a predetermined rate from a storage container. To be optimally effective, the pellets should be capable of producing a significant BTU level of heat output, be clean burning, produce minimal ash residue, be capable of long term storage withou...

AI Technical Summary

Benefits of technology

[0009]The present invention involves making a fuel pellet having principal ingredients being flax stem fiber material and a binder, preferably a vegetable oil or oilseed lubricant material. The fuel pellet of the present invention burns at a high temperature, generates little to no smoke, ash or creosote. In addition, the fuel pellets of the present invention can be stored for long periods without rotting or deteriorating. In preferred embodiments, the fuel pellet of the present invention includes at least about 60% by wt. flax stem fiber material; wherein the flax stem fiber material includes particles of different sizes; wherein at least about 60% of the particles are less than about a quarter of an inch in length; wherein the fuel pellet, when burned, produces less than about 4% ash residue. The present fuel pellets are made from waste material generally available at minimal cost that produces pellets that burn at a high temperature, generate little smoke and less than about 4% ash residue, and can be stored for long periods without deteriorating. The cost involved is often just the cost of bailing the unwanted flax straw and transporting the bailed flax straw to either a storage site or a processing site. Flax straw is remarkably durable over time. Growers are anxious to have it removed from their land as it can only be effectively disposed of by burning it, unless it is removed. Growers have found that flax straw is so resistant to decomposition, that it cannot be satisfactorily disposed of by plowing it into the soil. Preferred fuel pellets include at least about 60% by wt. flax stem fiber; wherein at least about 60% of the particles are less than about a quarter of an inch in length. The fuel pellet is processed by first selecting or processing the flax stem fiber so that it has a moisture content of from about 5 to about 12%. The bulk flax stem fiber material is then processed in a hammermill or the like to reduce the size of the fiber particles. The processed flax is then extruded through a commercial pelletizing machine. The pellets are then cut and then dried.

[0010]Oilseeds or vegetable oil derived from oilseeds are preferably used as a binder and lubricant, but they also ease the flow of the flax stem fiber material through the pellet mill / extruder, thereby reducing the pressure created during the forming processes by lubricating the substrate material. Further, vegetable oil or oilseeds increase the BTU content of the finished product. The vegetable oil or oilseeds are added at a ratio of from about 1 to about 50% by wt., preferably no greater than 5% by wt., either by the addition of processed vegetable oils or by the addition of oilseeds added to the reduced flax straw or flax stem fiber material.

[0011]Flax is a plant with blue flowers and oil carrying seeds and is mainly an oilseed crop grown almost exclusively for its seeds. The seeds are typically harvested and later pressed to extract the oil. Flaxseed oil is quite desirable due to its high unsaturated fat content. It has multiple uses including the production of linseed oil and can be an ingredient in various food commodities. The flax plant is a relatively short stature, commonly reaching fully grown heights of 12″ to 36″. The stem fiber or straw left over from the production of flax is both wiry and durable. The stalk residue remaining after harvesting of the flax is a serious problem for farmers because it is exceptionally resistant to decomposition / rotting. The flax straw is equally resistant to decomposition / rotting and is usually windrowed by growers and later burned just for disposal. As indicated above, flax straw is not easily disposed of by plowing it into the ground like corn stalks because of its resistance to decomposition. Attempts to plow flax straw into the ground often result in clogged harrows used to perform that task and the flax does not deteriorate easily or quickly as corn fodder and other crop fiber residues generally do. Flax straw is typically windrowed at the time of harvest and burned in fields by farmers in the fall. The burning presents environmental issues due to the release of heat / energy and carbon dioxide into the atmosphere without making appropriate use of the energy, as well as increased costs and risk to the farmer. Flax straw is preferred as the primary resource for making flax stern fiber material used in preferred embodiments of the present fuel pellets.

[0014]The present invention relates to creating a fuel pellet from the flax stem fiber waste. The fuel pellet is preferably manufactured by first processing the flax stem fiber material. In preferred embodiments, the bulk flax stem fiber is run through a hammermill, a grinder or the like, with a suitable amount of water, optionally in the form of steam used to add moisture to the flax stem fiber material, to process the flax stem fiber. In preferred embodiments, the flax stem fiber material is reduced in particle size by as much as possible by means of hammermill processing to allow for more efficient processing, greater pellet density and better finished product cohesion. The reduced flax straw material must then be assessed for moisture content, so as to determine the need to add or subtract moisture level for optimum extrusion results. The preferred moisture level for extrusion of the milled flax straw is preferably from about 5 to about 12%. The flax straw is fed into the intake chamber of an industrial pellet mill, in this case a California Pellet Mill (CPM) model 100C, where the straw is drawn into the machine by means of a variable speed mechanical auger. If the addition of moisture is indicated, this increased moisture level is preferably achieved by the addition of steam. High temperature steam, preferably in excess of 500 degrees F., generally referred to as “dry steam”, is believed to be more effective for the successful addition of moisture to flax straw, resulting in moisture penetration into the straw core and thus raising moisture levels without excess water on the surface of the stems and straw material, and resulting in better extrusion of the base product. If the flax straw has too much moisture content, a number of strategies can be employed to reduce the moisture content of the base product, including air drying of the base product, the addition of dry flax straw or dry reduced flax straw, or the forced drying of the product by means of forcing heated air over the flax straw material.

[0017]An important aspect of the present invention is the fuel pellet's low carbon dioxide emission and its effect under the Kyoto Protocol. Countries that ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading if they maintain or increase emissions of these gases. Under the Kyoto Protocol, each country ratifying the agreement is allotted a certain amount of carbon credits to be divided amongst that country's companies. Each company must either stay within their allotted amount of carbon emissions (carbon credits) or must purchase carbon credits from another party who will not use all of their carbon credits. This scenario has formed a new form of investment and emissions trading. Companies able to decrease their carbon emissions have the incentive to do so not only to ensure they stay within their allotment but also to save carbon credits for selling. One such member of the Kyoto Protocol is Canada. Canada's proximity to North Dakota, an abundant source of flax material, makes the fuel pellets of the present invention not only an environmentally and convenient source of fuel but also a valuable investment for the trading of carbon credits.

Problems solved by technology

The cost involved is often just the cost of bailing the unwanted flax straw and transporting the bailed flax straw to either a storage site or a processing site.

Growers are anxious to have it removed from their land as it can only be effectively disposed of by burning it, unless it is removed.

Growers have found that flax straw is so resistant to decomposition, that it cannot be satisfactorily disposed of by plowing it into the soil.

The stalk residue remaining after harvesting of the flax is a serious problem for farmers because it is exceptionally resistant to decomposition / rotting.

As indicated above, flax straw is not easily disposed of by plowing it into the ground like corn stalks because of its resistance to decomposition.

Attempts to plow flax straw into the ground often result in clogged harrows used to perform that task and the flax does not deteriorate easily or quickly as corn fodder and other crop fiber residues generally do.

The burning presents environmental issues due to the release of heat / energy and carbon dioxide into the atmosphere without making appropriate use of the energy, as well as increased costs and risk to the farmer.