GB2585189A

GB2585189A - Biomass fuel elements

Info

Publication number: GB2585189A
Application number: GB1909207.1A
Authority: GB
Inventors: Mark Hall Harry
Original assignee: Hall Hunter Partnership Farming
Current assignee: Hall Hunter Partnership Farming
Priority date: 2019-06-26
Filing date: 2019-06-26
Publication date: 2021-01-06
Also published as: GB201909207D0

Abstract

A process for producing biomass fuel elements, comprising the steps of: a. obtaining a by-product of a plant growing process wherein coir has been used as a growing medium, the by-product comprising a quantity of coir fibres and including some residual plant matter; b. adjusting the moisture content of said by-product to 10-25%; and c. subsequently using a brick press to form discrete biomass fuel elements.

Description

BIOMASS FUEL ELEMENTS

The present invention relates to biomass fuel elements. Specifically, but not necessarily exclusively the invention relates to a process for producing low emission and low carbon footprint biomass fuel elements, and a biomass fuel element formed 5 by such a process.

Background to the invention

Biomass fuel as a green energy source has been known in the art for many years, and there is an ongoing effort to use more green, and carbon neutral/ carbon negative processes. This effort is driven at least by government initiatives, for io example the Sustainable Development Goals issued by the council of the United Nations which encourage cleaner living, and additionally by growing concerns over climate change.

In general, green waste, or biomass, can be described as any unwanted organic byproduct of a process or system, for example crop growth. Use of such waste in the process of generating fuel elements is considered, at least in general, to have less harmful emissions than, for example, using fossil fuels.

Although biomass pellets may be a preferable source of energy over oil, gas and coal, there is an ongoing desire to improve the generation, production and carbon emissions of biomass fuel pellets.

Statements of the invention

Aspects of the present invention aim to address at least some of the above-described issues. In accordance with a first aspect of the present invention there is provided a process for producing biomass fuel elements, comprising the steps of: a. obtaining a by-product of a plant growing process wherein coir has been used as a growing medium, the by-product comprising a quantity of coir fibres in which plants have been grown and including some residual plant matter; b. adjusting the moisture content of said by-product to between 15-20%; c. subsequently using a brick press to form said by-product into a compact mass; and d. forming said compact mass into discrete fuel elements.

The resulting elements created using this process have surprisingly low emissions so and make use of a waste product which has previously been disregarded as having no further use.

In accordance with one exemplary embodiment of the invention, the moisture content of said by-product may be adjusted to about 18%. The step of adjusting the moisture content of said by-product may include drying said by-product. Optionally, the step of drying said by-product may include air-drying said by-product.

In one exemplary embodiment of the invention, the by-product may comprise only coir and plant matter. Optionally, plant matter may be root matter. In an exemplary embodiment, the plants are soft-fruit plants.

In an exemplary embodiment of the invention, the brick press may be mobile.

Optionally, the fuel element may be puck-shaped, pellet-shaped, brick or briquette shaped.

Optionally, the process may further comprise the step of, after adjusting the moisture content, shredding the by-product.

In accordance with a second aspect of the present invention there is provided a biomass fuel pellet made using the process of claim 1 of the appended claims.

Brief description of the drawings

Embodiments of the invention will now be described by reference to specific s examples as illustrated in the accompanying drawings, in which: Figure 1 is a schematic diagram of a method of forming fuel pellets from coconut coir according to a first exemplary embodiment of the invention; Figure 2 is a schematic diagram of a system from which coconut coir pellets can be created and then used according to an exemplary embodiment of the invention; and Figure 3 is a schematic diagram of a mobile brick press for use in the process according to an exemplary embodiment of the invention.

Specific Description

Coconut coir, also referred to as coco coir, is a fibrous material derived from the husk of a coconut. The fibres have many characteristics making them suitable for many different applications including filtration, brush making, rope making and more.

The strong, absorbent fibres make the coir an excellent growing medium for use in crop farming, in particular growing soft-fruit. Other types of plants may be grown in coir, and the invention is not necessarily intended to be limited in this regard.

In accordance with a first exemplary embodiment of the invention, a process for generating a biomass fuel element having low emissions and a low carbon footprint is described. Referring to Figures 1 and 2 of the drawings, at step 10 coir 20 is used as a growing medium for soft-fruit plants 22, during which time the coir 20 absorbs water from the irrigation or watering system 26 used. When grown commercially, soft-fruit and other crops can be is in polytunnels. Indeed, coir can be used as a growing medium for many different plant types, including soft fruit, of which can be grown outside, in a polytunnel or a glasshouse. Those skilled in the art will know that the regulatory systems present in the polytunnels will depend on the ambient climate outside the polytunnels, as well as they type of crop being grown and, while the invention is not necessarily limited in this regard, the subsequent drying process (described below) may be quicker and easier if the plants are grown in a polytunnel or glasshouse, depending on the time of year (and, therefore, the ambient io temperature outside).

The plant roots 24 grow into the coir 20 and become entangled with the fibres. The plants 22 will eventually generate a crop which may be collected by the producer.

At step 12 of the process, the producer finishes cropping, harvests and removes any irrigation system. At this point, the coir which has been the growing medium for the plants and now includes plant matter is a by-product 29 of the production process.

Plant matter may optionally also include leaves, stems, petals, pollen, flower buds and other plant matter not otherwise harvested. Plant matter in this particular circumstance means primarily root matter. In prior art processes, the coir by-product 29 would have been discarded. The by-product 29 can simply be left in the polytunnels once the crop has been harvested.

The next step 14 of the method according to an exemplary embodiment of the present invention is to control the moisture content so that the moisture content is at or at least near to 15% -20%. Preferably, the moisture content is at or at least near to 18%. This is important because otherwise the fuel elements created from this process would not burn as well, or would not form the compact biomass fuel element shape.

One suitable method for adjusting the moisture content of the by-product is to simply allow the by-product 29 to dry by evaporative methods. This is the preferred method for the present invention. The by-product 29 is left in-situ, for example within the polytunnel where the plant growing took place, and over time the water in the byproduct evaporates away. When the by-product has reached the desired moisture content, the next step can begin. This may take a variable period of time, depending on, for example, the time of year and the ambient temperature outside. Passing hot or warm air over the by-product would speed up this process. This can be done while the by-product 29 is still in the polytunnels, therefore reducing the need to transport the by-product 29. Suitable methods for testing the moisture content will be known to those skilled in the art and the present invention is not necessarily intended to be limited in this regard.

The person skilled in the art will know there are other suitable options for adjusting the moisture content of the by-product to achieve the desired moisture content without reducing the quality of the by-product 29 for use as a biomass fuel, and the invention is not necessarily intended to be limited in this regard.

This step is done on-site within the polytunnel itself so that transportation of the by-product 29 is kept to a minimum. In the case that the plant is grown in a glasshouse, the drying process would be the same, wherein the by-product is left in situ to dry by evaporative means. If the plants are grown outside, the by-product 29 may be covered with a waterproof sheet, and then left to dry.

At step 16, once the moisture content of the by-product 29 is between 15% and 20%at or near to 18%, it is shredded and then fed directly into a (preferably) mobile brick press 30 (again preferably) on-site. The mobile brick press 30 may optionally include the shredding means so that the two steps can be done using one machine. Alternatively, the shredding device may be a separate device, and beneficially, mobile as well This is more efficient, and removes the need to transport the byproduct to a processing plant, for example.

Referring specifically to Figure 3 of the drawings, an exemplary brick press 30 is illustrated. The machine has an opening 31 for receipt of the by-product 29. An so agitator (not shown) moves the by-product 29 around inside the silo to feed it into the compression unit of the machine 30. The by-product is formed into bricks 35 which are expelled via the mouth 33 of the machine. The compression strength of the machine can be adjusted, providing more flexibility for the user to alter the density of the bricks created.

is Machines suitable for pelleting and pucking, and alternative machines for creating bricks, will be known in the art and the present invention is not necessarily intended to be limited in this regard.

The brick 35 created by the machine is one example of a biomass fuel element 32 created by a process according to the invention. The biomass fuel elements 32 may take the form of a plurality of smaller cylindrical-shaped fuel pellets 32a or fuel pucks 32b, and may optionally be formed into a large brick 32c of compact biomass fuel. Other types of machines not illustrated in this description will be known to those skilled in the art and the invention is not necessarily limited in this regard.

The biomass fuel elements 32 generated from the process can be used as fuel for a biomass boiler. When burned, the compact biomass fuel elements 32 (which is comprised mainly of coir and plant matter) yields a surprisingly low harmful gas and particulate emission.

Referring particularly to Figure 2 of the drawings, an example of the invention in use shows how the energy within the system is used efficiently. Coir 20 is used as a growing medium for growing plants 22. The plants 22 may be located in polytunnels, as described above, or in glasshouse facilities, or outside. Irrigation 26 provides water and nutrients to enable to plants 22 to grow in the coir growing medium. Once so the crop has been harvested, the by-product 29 of the plant growing process (comprising coir and residual plant matter) is left in situ to air-dry by evaporative means. Next, once the by-product 29 has reached an optimal moisture content (i.e. less than 20%, preferably between 15% and 20%, and more preferably 18%) the byproduct 29 is shredded and then compressed to form biomass fuel elements 32 in a mobile shredder and press/brick press 30, such as the one illustrated in Figure 3 of the drawings. The by-product 29 is taken directly from the location of the plant growing process and fed into the mobile shredder and brick press 30 in situ, avoiding the need to transport the by-product 29 anywhere. The press 30 may include an integral shredder, but the shredder may alternatively be a separate (beneficially mobile) machine. Other suitable machines are known in the art. Fuel pellets 32a, fuel pucks 32b, and fuel brick 32c, may be created, depending on requirements of the user. The biomass fuel elements 32 are then used to generate hot water in a biomass boiler 34. Hot water created from the biomass boiler 34 may be used as required. This may include, but is not limited to, heating systems for homes, heating polytunnels, etc. The gaseous emissions from burning the biomass fuel pellets 32 created in this process are significantly, and surprisingly, less than other known fuel pellets.

It can be seen, that the process makes use of a previously wasted by-product of the plant growing process. The overall waste of the plant growing process is therefore significantly reduced. Additionally, owing to the surprisingly low emissions from the burning of biomass fuel pellets created in this way, the use of such pellets contributes a significant improvement over the prior art. The process according to one exemplary embodiment of the invention reduces waste and harmful emissions, and this is in-line with many national and international initiatives, for example the Sustainable Development Goals.

It will be apparent to those skilled in the art that modifications and variations may be made to the above-described embodiments without departing from the scope of the invention as defined by the appended claims.

It is preferable that all elements of the process according to the present invention are locally positioned, or proximal, and the brick press and shredder are preferably mobile so as to significantly reduce the carbon footprint of the resulting fuel. It is significant that the resulting biomass fuel elements are comprised, at least partially, from coir as this has produced surprisingly low emissions in emissions testing.

Claims

CLAIMS1. A process for producing biomass fuel elements, comprising the steps of: a. obtaining a by-product of a plant growing process wherein coir has been used as a growing medium, the by-product comprising a quantity of coir fibres and including some residual plant matter; b. adjusting the moisture content of said by-product to 10-25%; c. subsequently using a brick press to form discrete biomass fuel elements.
2. A process according to claim 1, comprising adjusting the moisture content of so the by-product to 15-20%
3. A process according to claim 2, wherein the moisture content of said byproduct is adjusted to about 18%.
4. A process according to any of the preceding claims, wherein the step of adjusting the moisture content of said by-product includes drying said by-product.
5. A process according to claim 4, wherein the step of drying said by-product includes air-drying said by-product.
6. A process according to claim 4 comprises allowing the by-product to dry naturally at the location in which the plant growing process has taken place.
7. A process according to any of the preceding claims, wherein said by-product comprises primarily coir and plant matter.
8. A process according to claim 7, wherein said plant matter comprises root matter.
9. A process according to any preceding claim, wherein said plants are soft fruit plants.
10.A process according to any preceding claim, wherein the brick press is mobile.
11. A process according to any of the preceding claims, further comprising shredding said by-product prior to using said brick press, using a shredding machine to shred said by-product.
12.A process according to claim 11, wherein said shredding machine and brick press are integral with each other.
13.A process according to claim 12, wherein said brick press and shredding machine are separate devices.
14.A process according to claim 13, wherein said shredding machine is a mobile device.
15.A process according to any preceding claim, wherein said fuel element is puck-shaped, pellet-shaped, brick or briquette shaped.
16. A biomass fuel element made using the process of claim 1 to 15.