Energy carrier, use of energy carrier and method of manufacturing energy carrier

Abstract

An energy carrier comprises a carrier body (10) formed as a briquette or pellet comprising non-passivated silicon powder, and an ignition material coating (11), covering at least part of a surface of the carrier body (10). The ignition material coating (11) comprises an ignition material, suitable for igniting the carrier body (10).

Description

[0001] ENERGY CARRIER, USE OF ENERGY CARRIER AND METHOD OF MANUFACTURING

[0002] ENERGY CARRIER

[0003] Technical field

[0004] The present disclosure relates to an energy carrier, to a method of using such an energy carrier to generate thermal energy and to a method of manufacturing such an energy carrier.

[0005] Background

[0006] It is known from e.g. W02014 / 063740A1 to provide a combustion engine which uses metal as a combustible, or fuel.

[0007] However, using metals as a combustible present various challenges with regard to the handling of the high temperatures that occur in the combustion of metals, as well as with regard to the handling of combustion residues, in the form of exhaust gases and resulting oxides.

[0008] Moreover, with some metal fuels, while highly desirable as fuel, it may be difficult to initiate the combustion process needed to extract energy from the fuel.

[0009] Hence, there is a need for further improvements in energy carriers.

[0010] It is an objective of the present disclosure to provide an improved energy carrier.

[0011] The invention is defined by the appended dependent claims. Embodiments are set forth in the dependent claims, in the following description and in the attached drawings.

[0012] According to a first aspect, there is provided n energy carrier, comprising a carrier body formed as a briquette or pellet comprising non-passivated silicon powder, and an ignition material coating, covering at least part of a surface of the carrier body. The ignition material coating comprising an ignition material, suitable for igniting the carrier body.

[0013] A briquette, or pellet, is a cohesive body formed by pressing together particles of a material, in this case silicon. The pressing may be performed in the absence of any binding agent. Alternatively, a binding agent may be used, if preferred.

[0014] The ignition material coating reduces the ignition temperature necessary for igniting the energy carrier, as compared with the carrier body alone.

[0015] Moreover, the ignition material coating may contribute to maintaining the cohesiveness of the energy carrier, in particular where the carrier body is "lightly pressed", which facilitates combustion, as compared to a "heavily pressed" carrier body.

[0016] An energy carrier formed as per above provides for convenient handling, as it does not need to be specifically oriented in relation to an ignition flame, for it to ignite. It is sufficient to insert the energy carrier into the burner and direct a flame at the energy carrier to cause it to ignite.

[0017] Such an energy carrier is particularly convenient for use in a combustion device, wherein the energy carrier is received in a receptacle and caused to ignite by e.g. a gas flame that is directed towards the energy carrier.

[0018] The ignition material coating may have a thickness of about 10-1000 pm.

[0019] In particular, the ignition material coating may have a thickness of about 10- 50 pm, about 50-100 pm, about 100-150 pm, about 150-200 pm, about 200-300 pm, about 300-400 pm about 400-500 pm, about 500-600 pm, about 600-700 pm, about 700-800 pm, about 800-900 pm, or about 900-1000 pm.

[0020] The ignition material coating covers at least about 30 %, preferably at least about 50 %, at least about 70 %, at least about 90 %, at least about 95 %, at least about 99 %, or about 100 %, of the surface of the carrier body. Hence, the ignition material coating may cover less than the entire surface of the carrier body. In particular, the ignition material coating may cover about 30-40 %, about 40-50 %, about 50-60 %, about 60-70 %, about 70-80 %, about 80-90 % or about 90-100 % of the surface of the carrier body.

[0021] According to a second aspect, there is provided an energy carrier, comprising a shell, which encloses an amount of non-passivated silicon powder, the shell comprising an ignition material, suitable for igniting the silicon powder.

[0022] The silicon powder may be provided as loose, essentially uncompressed powder. The silicon powder may alternatively be provided as a cohesive body of compressed powder.

[0023] The ignition material may be a non-passivated metal selected from the group consisting of Mg, Na, Al, B, Ti, Zn, Fe, Cu, Ni, Pb and Sn. For example, while Mg has an ignition temperature of about 473 degC, it has a flame temperature of about 3100 degC, which is sufficient to cause Si to ignite.

[0024] The ignition material may be present in an amount of at least about 10 wt.-% of the ignition material coating, or of the shell, as the case may be.

[0025] In particular, the ignition material may be present in an amount of at least about 15 wt.-%, at least about 20 wt.-%, at least about 30 wt.-%, at least about 40 wt.-%, at least about 50 wt.-%, at least about 60 wt.-%, at least about 70 wt.-%, at least about 80 wt.-%, at least about 90 wt.-% or about 100 wt.-% of the shell.

[0026] The ignition material may comprise non-passivated silicon and the nonpassivated metal. In particular, the ignition material may comprise some 1-10 wt.-% of the non-passivated silicon metal.

[0027] In particular, the material may comprise a magnesium-silicon alloy, such as magnesium silicide (Mg2Si).

[0028] The silicon powder may comprise at least about 50 wt.-% silicon, preferably at least about 60 wt.-%, at least about 70 wt.-% , at least 80 wt.-%, at least about 90 wt.-% , at least about 95 wt.-% or at least about 98 wt.-% silicon.

[0029] The silicon powder may have a particle size of less than about 10 mm, preferably less than about 5 mm.

[0030] The energy carrier may further comprise an ignition body comprising a second ignition material, suitable for igniting the carrier body, wherein the ignition body is integrated with the carrier body.

[0031] The second ignition material may be a non-passivated metal selected from the group consisting of Mg, Na, Al, B, Ti, Zn, Fe, Cu, Ni, Pb and Sn. In particular, the second ignition material may be the same as the first ignition material.

[0032] The ignition body may be formed in a recess in the carrier body and may also be covered by the ignition material coating. In particular, the ignition body may be formed as a portion of the ignition material coating having increased thickness. According to a third aspect, there is provided use of an energy carrier as claimed in any one of the preceding claims in a combustion device, for generating thermal energy.

[0033] In such use, one or more such energy carriers may be provided in a combustion receptacle, whereby a gas torch or the like is directed towards the energy carrier(s) to cause ignition of the ignition material coating, which will then produce a sufficiently high temperature to ignite also the silicon powder forming the carrier body.

[0034] According to a fourth aspect, there is provided a method of manufacturing an energy carrier, comprising providing an amount of non-passivated silicon powder, providing an ignition material, pressing the non-passivated silicon powder into a briquette, and forming the ignition material into a coating covering at least 50 %, preferably about 100 %, of an outer surface of a carrier body.

[0035] The method may comprise a first pressing step of forming the carrier body by pressing the non-passivated silicon powder, and an application step of applying the ignition material onto the carrier body.

[0036] The method may further comprise a second pressing step of pressing the carrier body with the ignition material.

[0037] The second pressing step may be performed at a higher pressure and / or higher temperature than the first pressing step.

[0038] Alternatively, the method may comprise a single pressing step of pressing the ignition material and the non-passivated silicon powder to form the energy carrier.

[0039] The ignition material and the non-passivated silicon powder may be applied to a mold prior to said single pressing step.

[0040] According to a fifth aspect, there is provided a method of manufacturing an energy carrier, comprising providing an amount of non-passivated silicon powder, providing an ignition material, forming the ignition material into a shell, and providing the non-passivated silicon powder inside the shell.

[0041] The method non-passivated silicon powder may be provided as a loose, uncompressed powder inside the shell.

[0042] The non-passivated silicon powder may be provided as a cohesive body inside the shell.

[0043] Fig. 1 is a schematic illustration of an energy carrier.

[0044] Fig. 2 is a schematic flowchart of a method of forming the energy carrier.

[0045] Fig. 3 is a schematic flowchart of an alternative method of forming the energy carrier.

[0046] Detailed description

[0047] Referring to fig. 1, an energy carrier 1 in the form of a briquette or pellet comprises a carrier body 10 which may be formed by pressing together an amount of non-passivated silicon powder. The silicon powder may comprise at least about 50 wt.-% silicon, preferably at least about 60 wt.-%, at least about 70 wt.-% , at least 80 wt.-%, at least about 90 wt.-% , at least about 95 wt.-% or at least about 98 wt.-% silicon. In particular, it may be advantageous to use metallurgical grade silicon.

[0048] The silicon powder may have a particle size of less than about 10 mm, preferably less than about 5 mm.

[0049] In some applications, the silicon powder may have a particle size of about 0.1-0.2 mm, about 0.2-0.5 mm, about 0.5-0.7 mm, about 0.7-1 mm, about 1-3 mm, about 3-4 mm or about 4-5 mm.

[0050] In other applications, the silicon powder may have a particle size of about 1- 50 pm or of about 50-100 pm.

[0051] In yet further applications, the silicon powder may have a particle size of about 1-100 nm, about 100-200 nm, about 200-300 nm, about 300-400 nm, about 400-500 nm, about 500-600 nm, about 600-700 nm, about 700-800 nm, about 800- 900 nm, about 900-1000 nm.

[0052] An ignition material coating 11 is provided as an at least partial coating on the carrier body 10. The ignition material comprises, or consists of, at least one nonpassivated metal selected from the group consisting of Mg, Na, Al, B, Ti, Zn, Fe, Cu, Ni, Pb and Sn.

[0053] The ignition material may be present in the ignition material coating 11 in an amount of at least about 10 wt.-%. In particular, the ignition material may be present in an amount of at least about 15 wt.-%, at least about 20 wt.-%, at least about 30 wt.-%, at least about 40 wt.-%, at least about 50 wt.-%, at least about 60 wt.-%, at least about 70 wt.-%, at least about 80 wt.-%, at least about 90 wt.-% or about 100 wt.-%.

[0054] The ignition material coating 11 may have a thickness of about 10-500 pm. In particular, the ignition material coating 11 may have a thickness of about 10-50 pm, about 50-100 pm, about 100-150 pm, about 150-200 pm, about 200-300 pm, about 300-400 pm or about 400-500 pm.

[0055] The ignition material coating 11 may comprise non-passivated silicon and the one or more non-passivated metal.

[0056] In particular, the ignition material coating 11 may comprise an alloy of the non-passivated silicon and the one or more non-passivated metal, provided such alloy provides for a reduction in ignition temperature as compared to the carrier body 10.

[0057] Magnesium alloys with silicon can exhibit enhanced strength compared to pure magnesium. The addition of silicon to magnesium alloys can improve their mechanical properties, such as tensile strength, yield strength, and hardness. Silicon helps in strengthening the alloy by forming solid solutions and precipitates that contribute to the overall strength of the material. The amount of silicon needed to make a magnesium-silicon alloy stronger than pure magnesium can vary, but typically silicon content in the range of 1% to 10% or even higher is commonly used to enhance the strength of the alloy. Additionally, silicon can improve the alloy's wear resistance and creep resistance, making it suitable for applications requiring high strength and durability. Overall, the presence of silicon in magnesium alloys can positively impact their strength characteristics and would work perfectly as a coating or shell for the Silicon powder body This magnesium alloy would also be able to be ignited at a lower temperature and help ignite the Silicon powder inside the coating or shell.

[0058] The ignition temperature of a magnesium alloy with for example 30% magnesium and the rest being silicon would likely be higher compared to an alloy with 100 % magnesium. The presence of silicon in the alloy alters its properties, including its ignition temperature. Silicon can increase the ignition temperature of the alloy as silicon itself has a higher melting and ignition temperature compared to magnesium. This change in composition would affect the overall thermal properties of the alloy, potentially raising the ignition temperature compared to pure magnesium. However, the exact ignition temperature would depend on the specific composition and the exact percentages of magnesium and silicon in the alloy.

[0059] In a particular embodiment, the ignition material coating 11 may comprise magnesium silicide (Mg2Si).

[0060] The energy carrier may further comprise an ignition body 12 comprising a second ignition material, suitable for igniting the carrier body 10, wherein the ignition body 12 is integrated with the carrier body 10.

[0061] The second ignition material may be a non-passivated metal selected from the group consisting of Mg, Na, Al, B, Ti, Zn, Fe, Cu, Ni, Pb and Sn. In particular, the second ignition material may be the same as the first ignition material. Alternatively, the ignition body 12 may have a different composition compared with the coating 11. For example, the ignition body 12 may have a lower ignition temperature than the coating 11, which may be achieved by it containing more of the material having the lower ignition temperature, such as Mg, than the coating 11.

[0062] The ignition body 12 may be formed in a recess in the carrier body 10 and may also be covered by the ignition material coating 11. In particular, the ignition body 12 may be formed as a portion of the ignition material coating 11 having increased thickness.

[0063] There are various ways of forming the energy carrier 1.

[0064] One path towards such forming is to form the carrier body 10 first and then to coat this carrier body 10 in a subsequent step. The carrier body 10 may be completely formed before coating, or it may be formed by a first pressing step achieving partial cohesiveness, which may be followed by a second pressing step, at higher pressure, achieving the final degree of cohesiveness.

[0065] Another path is to form the carrier body 10 and the ignition material coating 11 in a single forming step, e.g. by laying up the coating and the silicon powder in a first layup step and then forming the carrier body 10 with the coating in a single pressing step.

[0066] Forming a briquette of non-passivated silicon particles with a particle size of less than 5 mm involves several steps. Below is a general description of such a process In a particle preparation step, it may be ensured that the silicon particles are non-passivated and have a particle size of less than 5 mm. It may be necessary to to grind larger particles down to the desired size.

[0067] In the event a binder is to be used (which may be optional), the silicon particles are mixed with a suitable binder. The binder may help the particles stick together and maintain the shape of the briquette. The choice of binder can depend on the specific application of the briquette.

[0068] The briquette is then formed by pressing into the desired briquette shape. This can be done using a briquette press, which applies a pressure to the silicon powder, or mixture, to form it into a solid briquette.

[0069] In the event a binder was used, the formed briquettes may be dried to remove any moisture and / or to harden the binder. This can be done in a drying oven or by air drying, depending on the binder used.

[0070] For a block of slightly pressed together metal powder, the ideal form of a silicon-magnesium compound coating would depend on factors such as the porosity of the block, the desired properties of the coating, and the application method. There are some things to be considered in selecting a suitable form of the siliconmagnesium compound for coating a carrier body 10.

[0071] A liquid solution or dispersion can be used, which may penetrate the pores of the metal powder block effectively, to provide uniform coverage and adhesion. However, it must be ensured that the liquid solution does not disrupt the structure of the metal powder block. A liquid solution or dispersion can be applied by dipping or immersion of the carrier body 10 into the liquid solution or dispersion. Alternatively, the liquid solution or dispersion may be rolled, brushed or sprayed onto the carrier body 10.

[0072] As another alternative, a paste or slurry can be formed an applied, which may enable manual or automated application for precise coating, and which can fill gaps and uneven surfaces in the slightly pressed metal powder block. It may need to be ensured that the paste or slurry has good adhesion properties to bond effectively to the carrier body 10.

[0073] Application in a powder form may allow for controlled application thickness and coverage. Such an application method may be suitable for fluidized bed coating or electrostatic deposition methods. Again it may need to be ensured that proper adhesion and coverage of the powder on the carrier body 10 is achieved.

[0074] It may also be possible to provide a preformed sheet or film, which could provide easy handling and application for uniform coverage. A sheet can be cut to fit the specific shape of the carrier body 10. Again, it needs to be ensured that the sheet or film adheres securely to the carrier body 10 surface.

[0075] The application of a coating according to any of the methods disclosed above may be followed by a subsequent pressing step for ensuring integration between the coating and the carrier body 10. Heat may be added during such pressing step to ensure proper adhesion.

[0076] Hence, referring to fig. 2, an energy carrier may be provided through the following process.

[0077] In a first step 100, the material for the carrier body 10 is provided and applied to a press mold.

[0078] In a second step 110, the material is pressed to form the carrier body 10.

[0079] In a third step 120, the material for the ignition material coating 11 is provided onto the carrier body 10.

[0080] In a fourth step 130, the coated carrier body 10 is pressed again, optionally at a higher pressure and temperature than in the first pressing step 110.

[0081] Referring to fig. 3, an energy carrier may be provided in an alternative process.

[0082] In a first step 200, the material for the ignition material coating 11 is provided and applied to a press mold.

[0083] In a second step 210, the material for the carrier body 10 is applied to the press mold.

[0084] In a third step 220, the materials are pressed to form the carrier body 10.

[0085] The resulting energy carrier 1 will thus have a coating of an ignition material. By coating a large portion of the surface of the carrier body 10, the relative orientation between an energy carrier fed to a combustion device and an ignition device, such as a gas flame, will be of less importance, which will facilitate the handling and operation of the energy carrier 1. In another embodiment, it is conceivable to provide an energy carrier having the ignition material coating 11 as a shell, which may be filled with a pressed silicon powder body, or even with uncompressed silicon powder.

[0086] Shells may be formed as halves which are joined together, or a more or less complete shell with a filling opening that may be closed.

[0087] The shell may have a thickness of about 0.1 mm to about 3 mm.

[0088] The energy carriers 1 may be prepared for being fed in a controlled manner to the combustion device. For example, the energy carriers 1 may be arranged on a web or conveyor adapted for feeding the energy carriers 1 towards the combustion device, and optionally for feeding them all the way to a combustion zone in the combustion device.

[0089] The energy carrier 1 may be ignited directly by a gas flame, provided the amount of ignition material in the ignition material coating 11 is sufficiently high.

[0090] Alternatively, further ignition material may be supplied, such as a small amount of magnesium, which is ignited by the gas flame and, in turn, ignites the ignition material coating 11.

Claims

CLAIMS1. An energy carrier, comprising: a carrier body (10) formed as a briquette or pellet comprising non-passivated silicon powder, and an ignition material coating (11), covering at least part of a surface of the carrier body (10), the ignition material coating (11) comprising an ignition material, suitable for igniting the carrier body (10).

2. The energy carrier as claimed in claim 1, wherein the ignition material coating (11) has a thickness of about 10-500 pm.

3. The energy carrier as claimed in claim 1 or 2, wherein the ignition material coating (11) covers at least about 30 %, preferably at least about 50 %, at least about 70 %, at least about 90 %, or about 100 %, of the surface of the carrier body (10).

4. An energy carrier, comprising a shell, which encloses an amount of non-passivated silicon powder, the shell comprising an ignition material, suitable for igniting the silicon powder.

5. The energy carrier as claimed in claim 4, wherein the silicon powder is provided as loose, essentially uncompressed powder.

6. The energy carrier as claimed in claim 4, wherein the silicon powder is provided as a cohesive body of compressed powder.

7. The energy carrier as claimed in any one of the preceding claims, wherein the ignition material is a non-passivated metal selected from the group consisting of Mg, Na, Al, B, Ti, Zn, Fe, Cu, Ni, Pb and Sn.

8. The energy carrier as claimed in any one of the preceding claims, wherein the ignition material is present in an amount of at least about 10 wt.-% of the ignition material coating or of the shell.

9. The energy carrier as claimed in any one of the preceding claims, wherein the ignition material comprises non-passivated silicon and the nonpassivated metal.

10. The energy carrier as claimed in any one of the preceding claims, wherein the ignition material comprises a magnesium-silicon alloy, in particular magnesium silicide (Mg2Si).

11. The energy carrier as claimed in claim any one of the preceding claims, wherein the silicon powder comprises at least about 50 wt.-% silicon, preferably at least about 60 wt.-%, at least about 70 wt.-% , at least 80 wt.-%, at least about 90 wt.-% , at least about 95 wt.-% or at least about 98 wt.-% silicon.

12. The energy carrier as claimed in claim any one of the preceding claims, wherein the silicon powder has a particle size of less than about 10 mm, preferably less than about 5 mm.

13. The energy carrier as claimed in any one of the preceding claims, further comprising an ignition body (12) comprising a second ignition material, suitable for igniting the carrier body (10), wherein the ignition body (12) is integrated with the carrier body (10).

14. Use of an energy carrier as claimed in any one of the preceding claims in a combustion device, for generating thermal energy.

15. A method of manufacturing an energy carrier, comprising: providing an amount of non-passivated silicon powder (100, 200), providing an ignition material (120, 200),pressing the non-passivated silicon powder into a briquette (110, 130; 220), and forming the ignition material (120, 200) into a coating covering at least 50 %, preferably about 100 %, of an outer surface of a carrier body (10).

16. The method as claimed in claim 15, wherein the method comprises: a first pressing step (110) of forming the carrier body by pressing the nonpassivated silicon powder, and an application step (120) of applying the ignition material onto the carrier body.

17. The method as claimed in claim 16, further comprising a second pressing step (230) of pressing the carrier body with the ignition material.

18. The method as claimed in claim 17, wherein the second pressing step (230) is performed at a higher pressure and / or higher temperature than the first pressing step (110).

19. The method as claimed in claim 16, wherein the method comprises a single pressing step (220) of pressing the ignition material and the non-passivated silicon powder to form the energy carrier.

20. The method as claimed in claim 19, wherein the ignition material and the non-passivated silicon powder are applied (200, 210) to a mold prior to said single pressing step (220).

21. A method of manufacturing an energy carrier, comprising: providing an amount of non-passivated silicon powder, providing an ignition material, forming the ignition material into a shell, and providing the non-passivated silicon powder inside the shell.

22. The method as claimed in claim 21, wherein the non-passivated silicon powder is provided as a loose, uncompressed powder inside the shell.

23. The method as claimed in claim 21, wherein the non-passivated silicon powder is provided as a cohesive body inside the shell.

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