Device for producing solid fuel in a form of shaped profiles and method for producing solid fuel

Abstract

 The invention relates to an apparatus for production of solid fuel in the form of pre-formed blocks, comprising at least one container for raw materials, connected with a granulator directly or indirectly with it by means of a fine grinding section and/or a homogenisation section, characterised in that the drum granulator (10) comprises a drum matrix (12) with holes (16) located on the external surface thereof and a roller (13) adjoining it from the outside and provided with punches (17) on its perimeter, wherein the matrix (12) rotation axis is parallel to the roller (13) rotation axis.

Description

[0001] The object of the invention is an apparatus for production of solid fuel in the form of pre-formed blocks and a method of solid fuel production.

[0002] Processes of treatment of fine-grained solid fuels, often waste ones, such as hard coal and/or lignite or coke which are left-overs of energy fuels featuring low usability are known. Processes of transforming solid fuels, e.g. by making briquettes, pellets or granulate also employ the use of biomass of various origin and possibly fillers and binders.

[0003] From the patent description PL035571 there is known a method of briquetting of the crumbled solid fuels by pressing a raw material blend, which has been previously heated up. In this method, raw materials are extruded in moulds and ready-made briquettes are shaken out.

[0004] From the patent description PL201369 there is known a method of producing solid fuel by homogenising and briquetting the ingredients, the key process phase taking place in a circular kneader.

[0005] The known processes of granulating solid fuels consist in forcing the homogenised raw material through a perforated matrixes are based on raking up the raw material which is forced through proper holes of the matrix under its own weight load or by the raking blades or by other forces exerted on the raw material blend. However, the raw material compaction is relatively loose and slightly porous and the structure of produced briquettes or pellets may comprise microcavities filled with air or volatile substances emitted in the raw material treatment process.

[0006] The invention makes it possible to use various components in the process of moulding crumbled solid fuels. Components of various types are known for example from the patent description PL194593 which revealed briquettes containing coal dust and/or coke and/or sawdust and/or peat and/or straw, and in which collagen produced from natural animal skins was used as a binder. In the Polish patent descriptions PL174678 and PL174972, crumbled energy wastes were briquetted with the use of starch and its derivatives which were additionally modified with urea-formaldehydes. Magnesium and zinc oxides were used a mineral binder in the briquetting process revealed in the Polish patent description PL177076.

[0007] The apparatus and the method according to the invention can be applied to any, e.g. aforementioned raw materials, mostly solid fuels based on coal, coke and biomass. The purpose of the invention is therefore to design an enhanced, universal apparatus to produce pre-formed solid fuels, especially a solid fuel granulator.

[0008] The apparatus for production of solid fuel in the form of pre-formed blocks, comprising a raw material container or containers connected with the granulator directly or indirectly through the raw material fine grinding or/and homogenisation section, includes, according to the invention, a drum granulator consisting of a drum matrix with holes situated on its external surface and a roller which adjoins it from the outside and is provided with punches on its perimeter, where the matrix rotation axis is parallel to the roller rotation axis and the length of the punches is equal to or smaller than the depth of the conical part of the holes, and the diameter of the punches is smaller than the diameter of the conical part of the holes which in the external part of the matrix have a conical shape and then in the internal part of the matrix have a shape of cylinders. The matrix is connected with a drive unit by means of a shaft and/or a roller is connected by means of a shaft with a drive unit. Inside the matrix, there is a solid fuel collecting duct receiving the fuel in the form of pre-formed blocks.

[0009] The object of the invention is also a method of producing solid fuel in the form of pre-formed blocks, comprising the raw material delivery through at least one container and optionally fine grinding and homogenisation of the raw material, characterised in that the fuel blocks are pre-formed in a drum granulator consisting of a drum matrix with holes which are situated on its external surface and through which, by means of a roller adjoining it from the outside and provided with punches on its perimeter, raw material is forced into the matrix, the raw material being charged gravitationally from the top of the granulator in the area where the matrix adjoins the roller.

[0010] The raw material is forced through the matrix holes by getting the matrix drum driven by a shaft as well as separately getting the roller driven by a shaft or by driving only the matrix drum or only the roller. The raw material is recirculated directly or indirectly below the granulator back to the granulator.

[0011] The object of the invention is shown in the embodiment on the drawing, wherein fig. 1 presents a layout of the apparatus with one container and a fine grinding and/or homogenising section, fig. 2 - a layout of the apparatus with four containers for various raw materials, fig. 3 - the apparatus with two containers, fig. 4 presents the apparatus with four containers and the fine grinding and/or homogenising section, fig. 5 - schematically a side view of the drum granulator with the marked "detail B" area, fig. 6 shows the detail B, i.e. a detailed cross-section view of the punches co-operating with the matrix holes, fig. 7 - a perspective view of the drum granulator with the direction of the raw material charge (S) and its recirculate flow (ZS) marked.

[0012] Fig. 1-4 shows various variants of the apparatuses comprising the drum granulator which makes the invention innovative. The apparatus according to the invention in its simplest embodiment comprises a raw material container or containers 1, 2, 3, 4, and a drum granulator 10 with a raw material recirculate flow feeder Z, connected with the aforementioned container(s) by means of the feeder 5 or feeders 5, 6, 7, 8, as it is shown in fig. 2 and 3.

[0013] In a more complex embodiment which is also typical for this field of industry, the apparatus comprises a container 1 or several containers, e.g. containers 1, 2, 3 i 4 for various kinds of raw materials, a fine grinding and/or homogenisation section 9 and a feeder 11 connecting that section with a drum granulator 10 provided with a raw material recierculate flow feeder Z. Such example of the apparatuses is shown in fig. 1 and 4.

[0014] These examples illustrate possible variants of the apparatus comprising a drum granulator; however, is is obvious for a professional that other combinations of the a.m. typical, known modules used in the apparatuses designed for briquetting or granulating solid fuels, i.e. drive units, power supply units, control panels, dust extraction systems, apparatuses designed to pre-heat raw material or to remove excessive humidity are also possible. Both the aforementioned apparatuses and the examples shown in fig. 1-4 do not constitute the essence of the solution. Its essence is an apparatus provided with a specifically designed drum granulator, of which the spatial arrangement and the principle of operation ensure an enhanced way of producing solid fuel in the form of e.g. granulate or pellets.

[0015] The apparatus for production of solid fuel in the form of pre-formed blocks comprises the drum granulator 10, an exemplary embodiment of which is shown in fig. 5-7. The granulator 10 is provided with a drum matrix 12 fixed on a shaft 14 and provided with moulding holes 16 and a roller 13 fixed on a shaft 15 and comprising punches 17 on its perimeter. The holes 16 have a conical shape in the external part (adjoining the punches 17) and deep inside the matrix they change over to the cylindrical holes 18. From the internal side 19 of the drum matrix, the ready formed solid fuel blocks are collected. They can be collected, e.g. through a duct with various types of rakes.

[0016] Fig. 7 shows the arrow S which indicates the direction of the gravitational downward raw material charge into the drum granulator. The raw material is crushed between the matrix and the roller with the punches. These two co-operating components move in mutually opposite directions which cause raking of the raw material between the matrix drum and the roller with the punches, and causes crushing the raw material between the adjoining side walls of the matrix drum and the roller with punches. In case when only the matrix or only the roller with the punches is connected with the drive unit, it is necessary to mutually transmit the power by the effect of gearing of the punches with the matrix holes. However, in case when both co-operating elements, i.e. the matrix as well as the roller with the punches are connected with the drive units and driven autonomously (which is a variant of the invention), then the rotational speeds of the matrix and the roller are specifically adjusted to prevent the punches from contacting the matrix in course of the operation. The operating elements do not come in contact with one another as an adequately precise transmission ratio is applied. Such solution significantly increases the lifetime of the apparatus by eliminating friction between metals.

[0017] The direction of movement of the drive shafts 14 and 15 is illustrated by means of arrows in fig. 7. Fig. 7 shows also the direction of delivery of the raw material which is not used in the process and which is turned back to the drum granulator directly or possibly by means of a container and the fine grinding and/or homogenisation section.

[0018] Both the matrix 12 and the roller 13 with the punches 17 can be driven by propeller shafts 14 and 15 or in another embodiment of the apparatus, only the roller with the punches or only the matrix can be driven, allowing the non-driven element adjust itself freely to the motion of the driven element. It is desirable while producing bigger solid fuel blocks.

[0019] Both the matrix and the roller with the punches have a cylindrical shape but their diameter can be freely adjusted in some measure - these do not have to be elements of the same diameter.

[0020] The apparatus and the method according to the invention are based on the application of a granulator featuring a special new design which makes it possible to significantly increase the raw material congestion to the form of hard, small size granules (pellets) or to produce larger size cylindrical briquettes, depending on the size of the used punches and holes in the drum matrix.

[0021] The raw materials are pressed under the pressure exerted by the punches hitting the matrix holes which allows achieving greater compaction (increasing the density) of the produced pellets.

[0022] In the apparatus according to the invention, it is possible to use a separate drive of the matrix with holes and the drum with punches which is preferable while producing small size granules or pellets. It is also possible to use a drive of only one co-operating element - for larger size briquettes. In that case, the punches become a part of the meshing gear, transmitting motion from one element onto the other while cooperating with the holes in the matrix. The risk of damaging the punches which could occur while producing big pellets with the use of drives both of the matrix as well as the roller with the punches is reduced.

[0023] The holes in the matrix have, in the external part (the the side of the roller with the punches), a conical shape which widens in the direction of the punches. The holes are further cylindrical. Such shape of the matrix holes allows the occurrence of minimum displacements between the settings of the punches and the holes so as to prevent these differences from causing additional resistance and possible damages in course of the granulator operation. The roller with the punches is made in such way that the length of the punches is not bigger than the depth of the conical part of the holes in the moulding matrix. The punches can have a shape of a cylinder or a cut cone. The shape of a conical punch is adjusted to fit the shape of the conical hole in the matrix.

[0024] The possibility of adjusting sizes of the matrix holes and the punches as well as changing the type of the drive of the co-operating elements of the granulator allows making granulates (pellets) of blends of materials featuring different physical properties, e.g. biomass and coal.

[0025] The granulator can comprise a drum matrix with holes situated in any way in a few / several rows with various spacings, designed to suit the kind of the raw material actually processed and resistance occurring in course of the process. The drum with adequately pre-set punches must co-operate with the matrix holes, so the sizes of the holes and the punches, their quantity and location on the perimeter of the drum must mutually correspond.

[0026] The setting of the matrix with the holes and the co-operating punches in such a way that the granulator is fed with the raw material vertically from the top additionally performs the function of "pressing" the raw material blend between the rotating matrix and the roller with the punches so that pressing the material through the matrix holes is facilitated.

[0027] The method according to the invention is used to obtain solid fuel in the form of pre-formed blocks in the shape of granules or pellets. The apparatus according to the invention can comprise a container or several containers for various individual raw materials, i.e. lignite and/or hard coal, biomass, fillers and binders. Individual raw materials are supplied by feeders to the fine grinding and/or homogenisation section and another feeder is used to supply a homogeneous blend to the drum granulator where the raw material blend is supplied from the top towards the drum matrix and the roller with the punches while the matrix and the roller rotate in mutually opposite directions and it is forced by the punches through the holes in the drum matrix inside the matrix drum from where the product is collected. Simultaneously, the raw material blend is turned back below the matrix and the roller with the punches which co-operate with each other.

[0028] In the method according to the invention it is required to turn back the raw material which has not been formed as granulate. The recirculated raw material is possibly inspected and homogenised with the output raw materials.

[0029] The method according to the invention in the embodiment allows producing granulate (pellets, briquettes), the form of which results from the shape of the round holes of the matrix. In principle, the produced solid fuel can have any sizes (diameter and length), which are modified depending on raw materials or the pre-set purpose. The pre-formed solid fuel can, for example, have the length of a few / several centimetres or even less than one centimetre. Also, the diameter of the produced blocks can vary from several millimetres to several centimetres.

[0030] The drum granulator can, however, be modified in such a way that it comprises a matrix and adequately adjusted punches which allow producing granulate with cross sections other than circular.

[0031] The granulate produced by the method according to the invention can be burnt in any type of boiler with any type of stove. These can be automatic boilers with a retort furnace, boilers with a burner for pellet, fluidised bed boilers used in the power engineering sector, boilers with powdered fuel burners. The solid fuel produced by the method according to the invention is also suitable for being co-burnt with other solid fuels.

[0032] Examples of the raw materials used in the method according to the invention are presented below.

Example 1

[0033] Lignite dust with the grain size smaller than 50 mm, fed by means of the feeder 5 from the container 1 in the amount of 40 weight %, is blended in the fine grinding section 9 with the hard coal dust fed by means of the feeder 6 from the container 2 with the grain size smaller than 10mm in the amount of 60 weight % until a homogeneous blend is produced. The homogeneous blend is fed by the feeder 11 to the drum granulator where the solid fuel is formed.

Example 2

[0034] According to the example 1, granulate was produced from a blend comprising 50 weight % of lignite.

Example 3

[0035] Coal dust with the grain size smaller than 50 mm in the amount of 60 weight %, fed from the container 1 or 2, plant biomass with 15% moisture content supplied from the container 3 in the amount of 30 % weight and a mineral binder from the container 4 in the amount of 10 weight % are supplied to the homogenisation section 9 and blended until a homogeneous blend is produced, and then supplied by means of the feeder 11 to the drum granulator 10 where it converted into pellets.

Example 4

[0036] The crumbled biomass in the form of milled waste from a woodwork process, along with tree bark with the grain size smaller than 5 mm and low moisture level at approx.10%, is supplied from the container 3, blended with hydrated lime Ca(OH)2 from the container 4 in the amount of 10 volumetric units in relation to the biomass amount, left for 16 hours and then blended with coal dust (hard coal) from the container 1, in 1:1 volumetric ratio, i.e. in the amount of 50 volumetric units of the coal dust per 50 volumetric units of the biomass in the blend with the hydrated lime; volatile ash from the container 4 is added in the amount of the 5 weight units in relation to the total weight of the coal dust and the biomass in the blend with the hydrated lime and then the produced homogenised blend is fed by means of the feeder 11 to the drum granulator 10 where it is granulated.

Claims

1. An apparatus for production of solid fuel in the form of pre-formed blocks, comprising at least one container for raw materials connected with a granulator directly or indirectly by means of a fine grinding section and/or a homogenisation section, characterised in that the drum granulator (10) comprises a drum matrix (12) with holes (16) located on the external surface thereof and a roller (13) adjoining it from the outside and provided with punches (17) on its perimeter, wherein the matrix (12) rotation axis is parallel to the roller (13) rotation axis.

2. The apparatus according to claim 1, characterised in that the length of the punches (17) is equal to or smaller than the depth of the conical part of the holes (16), and the diameter of the punches (17) is smaller than the diameter of the conical part of the holes (16).

3. The apparatus according to claim 1 or 2, characterised in that the holes (16) in the external part of the matrix (12) have a conical shape and then in the internal part of the matrix (12) they have a shape of cylinders (18).

4. The apparatus according to claim 1 or 2 or 3, characterised in that the matrix (12) is connected by a shaft (14) with a drive unit and/or the roller (13) is connected by a shaft (15) with a drive unit.

5. The apparatus according to claim 1 or 2 or 3 or 4, characterised in that inside the matrix (12) there is a channel (19) for collecting of the solid fuel in the form of pre-formed blocks.

6. A method of producing solid fuel in the form of pre-formed blocks, comprising the raw material delivery by means of at least one container and optionally fine grinding and homogenisation of the raw material, characterised in that the fuel blocks are pre-formed in a drum granulator (10) comprising a drum matrix (12) with holes (16), which are situated on its external surface and through which, by means of a roller (13) adjoining it from the outside and provided with punches (17) on its perimeter, the raw material is forced into the matrix (12), wherein the raw material is charged gravitationally from the top of the granulator (10) in the area where the matrix (12) adjoins the roller (13).

7. The method according to claim 6, characterised in that the raw material is forced through the holes (16) of the matrix (12) by driving the matrix (12) drum with the shaft (14) as well as separately driving the roller (13) with the shaft (15) or by driving only the matrix (12) drum or by driving only the roller (13).

8. The method according to claim 6 or 7, characterised in that below the granulator (10) the raw material is recirculated directly or indirectly back to the granulator (10).

Drawing