Patent Description:
In many cases, processing of materials such as wood or other biological material comprises temperature treatment that can be for example pyrolysis, torrefaction, or any other heat treatment, as well as cold treatment. Pyrolysis is thermal decomposition of materials at elevated temperatures in an inert gas-content environment. Pyrolysis is commonly used in treatment of organic materials such as wood. It is one of the processes involved in charring wood. In general, pyrolysis of organic substances produces volatile products and leaves a solid residue enriched in carbon called charcoal. Extreme pyrolysis, which leaves mostly carbon as the residue, is called carbonization. Torrefaction of biomass, e.g. wood or grain, is a mild form of pyrolysis at temperatures typically between <NUM> and <NUM>. Torrefaction is typically carried out under normal atmospheric pressure and in the absence of oxygen, i.e. with no air. During the torrefaction process, water contained in the biomass as well as superfluous volatiles are released, and the biopolymers such as cellulose, hemicellulose, and lignin partly decompose, giving off various types of volatiles. The final product is solid, dry, and blackened material that is referred to as torrefied biomass or bio-coal. Many biomass fuels, regardless of their origins, produce torrefied products with similar properties - except for ash properties which largely reflect the original fuel ash content and composition. Thus, torrefaction can be used for obtaining homogeneous product composition regardless of origin of starting biomaterials. Furthermore, torrefied biomass has hydrophobic properties, i.e. repels water, which facilitates storage.

A processing device for temperature treatment of the kind discussed above comprises typically a treatment chamber whose gas-content and temperature can be controlled. In many cases, a temperature treatment process is wanted to be a continuous process where material to be treated is continuously or nearly continuously supplied to an inlet of a processing device and the temperature treated material is continuously of nearly continuously taken out from an outlet of the processing device. The processing device comprises conveying means such as a conveyor belt or a screw conveyor which transfer the material to be treated from the inlet to the outlet. The temperature treatment, e.g. pyrolysis or torrefaction, takes place during the transfer. Publication <CIT> describes a processing device for preparing charcoal, wood tar, wood vinegar, and heat energy through biomass pyrolysis carbonization.

An inherent challenge related to many processing devices of the kind mentioned above is that the conveying means require room and thus the volume of a room whose temperature and gas-content are to be controlled can be so large that the control is complicated and slow to react to required changes. The documents <CIT>, <CIT>, and <CIT> disclose processing devices and methods according to the state of the art.

The following presents a simplified summary in order to provide a basic understanding of some embodiments of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention, which is defined in the appended claims. In this document, the word "geometric" when used as a prefix means a geometric concept that is not necessarily a part of any physical object. The geometric concept can be for example a geometric point, a straight or curved geometric line, a geometric plane, a non-planar geometric surface, a geometric room, or any other geometric entity that is zero, one, two, or three dimensional.

In accordance with the invention, there is provided a new processing device for temperature treatment of materials. The temperature treatment can be for example pyrolysis, torrefaction, or any other heat treatment, as well as cold treatment.

A processing device according to the invention comprises:.

The above-mentioned interior room contains a drive mechanism configured to drive the conveyor belt. The drive mechanism comprises a first wheel supporting the conveyor belt at the first end of the treatment room and a second wheel supporting the conveyor belt at the second end of the treatment room. The wall structures are configured to exclude a room being between the first and second wheels out from the interior room to make the interior room smaller and thereby to facilitate temperature control as well as possible gas-content control of the treatment room. The wall structures are configured to constitute a first tubular part containing a first part of the conveyor belt being between the first and second wheels and a second tubular part containing a second part of the conveyor belt being between the first and second wheels, the first tubular part forming at least a part of the treatment room.

In this document, the word "room" means a three-dimensional spatial area. In this document, the word "gas-content" means gas or gases which are present in a room under consideration.

In accordance with the invention, there is also provided a new method for temperature treatment of material. A method according to the invention comprises:.

In a method according to an exemplifying and non-limiting embodiment, the material supplied to the inlet of the processing device is wood and the temperature treated material received from the outlet of the processing device is charcoal.

Exemplifying and non-limiting embodiments are described in accompanied dependent claims.

Various exemplifying and non-limiting embodiments both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying embodiments when read in connection with the accompanying drawings.

The features recited in the accompanied dependent claims are mutually freely combinable unless otherwise explicitly stated.

Exemplifying and non-limiting embodiments and their advantages are explained in greater details below in the sense of examples and with reference to the accompanying drawings, in which:.

The specific examples provided in the description below should not be construed as limiting the scope and/or the applicability of the accompanied claims. Lists and groups of examples provided in the description are not exhaustive unless otherwise explicitly stated.

<FIG> shows a processing device according to an exemplifying and non-limiting embodiment for temperature treatment. <FIG> shows a section of the processing device so that the geometric section plane is parallel with the xz-plane of a coordinate system <NUM>. The processing device comprises wall structures <NUM> which define an interior room <NUM>. The processing device comprises a temperature control device <NUM> configured to control temperature of a treatment room <NUM> that is a part of the interior room <NUM>. The temperature control device <NUM> can be a heater that may comprise for example gas or oil burners, or an electrical heater. In an exemplifying case in which the processing device is a cold treatment device, the temperature control device <NUM> can be an electrical cooler. The processing device comprises an inlet <NUM> that is configured to supply material to be treated to a first end of the treatment room <NUM>. The material to be treated can be fort example biological material such as wood. The processing device comprises a conveyor belt <NUM> that constitutes a closed loop and is configured to transfer the material inside the treatment room <NUM> from the first end of the treatment room <NUM> to a second end of the treatment room <NUM>. The processing device comprises an outlet <NUM> configured to remove the temperature treated material from the second end of the treatment room <NUM>. The interior room <NUM> contains a drive mechanism configured to drive the conveyor belt <NUM>. The drive mechanism comprises a first wheel <NUM> supporting the conveyor belt <NUM> at the first end of the treatment room <NUM> and a second wheel <NUM> supporting the conveyor belt <NUM> at the second end of the treatment room <NUM>. The wall structures <NUM> of the processing device are configured to exclude a room <NUM> that is between the above-mentioned first and second wheels <NUM> and <NUM> out from the interior room <NUM> room to make the interior room <NUM> smaller and thereby to facilitate temperature control as well as possible gas-content control of the treatment room <NUM>. The processing device may further comprise a motor system connected to the first and/or second wheels <NUM> and <NUM>. The motor system is not shown in <FIG>. It is also possible that a processing device according to an exemplifying and non-limiting embodiment can be connected to an external motor system.

In the exemplifying processing device illustrated in <FIG>, the temperature control device <NUM> is located outside the interior room <NUM> and between the first and second wheels <NUM> and <NUM>. The temperature control device <NUM> is configured to be in a heat transfer connection with the treatment room <NUM>. It is also possible that a temperature control device of a processing device according to an exemplifying and non-limiting embodiment is inside the treatment room <NUM>, e.g. below or above the conveyor belt.

In the exemplifying processing device illustrated in <FIG>, the wall structures <NUM> are configured to constitute a first tubular part <NUM> containing a first part, i.e. an upper part, of the conveyor belt <NUM> being between the first and second wheels <NUM> and <NUM> and a second tubular part <NUM> containing a second part, i.e. a lower part, of the conveyor belt <NUM> being between the first and second wheels <NUM> and <NUM>. As shown in <FIG>, the first tubular part <NUM> forms at least a part of the treatment room <NUM>.

A processing device according to an exemplifying and non-limiting embodiment comprises a gas-content control system <NUM> configured to control gas-content inside the treatment room <NUM>. Typically, the gas-content of the treatment room <NUM> is a low-oxygen or an oxygen-free gas-content. In the exemplifying processing device illustrated in <FIG>, the gas-content control system <NUM> comprises pressurized gas bottles configured supply, to the interior room <NUM>, gas representing a desired gas-content inside the treatment room <NUM>. The gas supplied to the interior room <NUM> may comprise for example nitrogen, carbon dioxide, helium, and/or argon.

In a processing device according to an exemplifying and non-limiting embodiment, the inlet comprises a first closing system configured to close the inlet to reduce gas leakage to and from the interior room <NUM>, and the outlet comprises a second closing system configured to close the outlet to reduce gas leakage to and from the interior room <NUM>. The first and second closing systems are not shown in <FIG>. Each of the first and second closing systems can be for example such as the closing system <NUM> whose section view is shown in <FIG>, or each of the first and second closing systems can be for example such as the closing system <NUM> whose section view is shown in <FIG>. The closing system <NUM> illustrated in <FIG> comprises a paddlewheel <NUM> placed in a cylindrical chamber <NUM> so that tips of vanes of the paddlewheel move along a wall of the cylindrical chamber <NUM> when the paddlewheel <NUM> rotates. The cylindrical chamber <NUM> has a supply aperture for receiving material and an exit aperture for removing the material from the cylindrical chamber <NUM>. <FIG> illustrates a situation in which the paddlewheel <NUM> rotates in a clockwise direction. Material flow is depicted with an arrow-headed dashed line. As shown in <FIG>, there is no direct flow path through the closing system <NUM>. The closing system <NUM> illustrated in <FIG> comprises plates <NUM> and <NUM> which are operated cyclically so that, at each time, only one of the plates <NUM> and <NUM> is in an open position or both the plates <NUM> and <NUM> are in a closed position. <FIG> show different operational phases of the closing system <NUM>. Arched dot-line arrows show transitions between these operational phases. As shown in <FIG>, there is no direct flow path through the closing system <NUM>.

In a processing device according to an exemplifying and non-limiting embodiment, the conveyor belt comprises transverse ridges configured to push the material to be treated in a moving direction of the conveyor belt. In <FIG>, one of the transverse ridges of the conveyor belt <NUM> is denoted with a reference <NUM>. It is also possible that sides of the conveyor belt <NUM> are provided with rims so that the conveyor belt <NUM> comprises trough-like elements that are successively in the direction of movement.

<FIG> shows a flowchart of a method according to an exemplifying and non-limiting embodiment for temperature treatment of material. The method comprises the following actions:.

The processing device can be for example such as illustrated in <FIG>. In a method according to an exemplifying and non-limiting embodiment, the material supplied to the inlet of the processing device is wood and the temperature treated material received from the outlet of the processing device is charcoal.

In a method according to an exemplifying and non-limiting embodiment, a temperature control device of the processing device is located outside a treatment room in which the temperature treatment takes place and between first and second wheels supporting a conveyor belt carrying the material in the treatment room, and the temperature control device is in a heat transfer connection with the treatment room.

In the method according to the invention, wall structures of the processing device constitute a first tubular part containing a first part of the conveyor belt being between the first and second wheels and a second tubular part containing a second part of the conveyor belt being between the first and second wheels, where the first tubular part forms at least a part of the treatment room in which the temperature treatment takes place.

A method according to an exemplifying and non-limiting embodiment comprises controlling a gas-content inside the treatment room. The gas-content inside the treatment room can be controlled to be a low-oxygen gas-content or an oxygen-free gas-content. In a method according to an exemplifying and non-limiting embodiment, the gas-content of the treatment room is controlled by supplying gas representing the desired gas-content from one or more pressurized gas bottles via one or more control valves to the interior room of the processing device. The supplied gas may comprise for example nitrogen, carbon dioxide, helium, and/or argon.

In a method according to an exemplifying and non-limiting embodiment, the inlet of the processing device comprises a first closing system configured to close the inlet to reduce gas leakage to and from the interior room of the processing device, and the outlet of the processing device comprises a second closing system configured to close the outlet to reduce gas leakage to and from the interior room.

In a method according to an exemplifying and non-limiting embodiment, each of the first and second closing systems comprises a paddlewheel placed in a cylindrical chamber so that tips of vanes of the paddlewheel move along a wall of the cylindrical chamber. The cylindrical chamber has a supply aperture for receiving material, and an exit aperture for removing the material from the cylindrical chamber.

In a method according to an exemplifying and non-limiting embodiment, the conveyor belt of the processing device comprises transverse ridges which push the material to be treated in a movement direction of the conveyor belt.

Claim 1:
A processing device for temperature treatment, the processing device comprising:
- wall structures (<NUM>) defining an interior room (<NUM>),
- a temperature control device (<NUM>) configured to control temperature of a treatment room (<NUM>) being a part of the interior room,
- an inlet (<NUM>) configured to supply material to be treated to a first end of the treatment room,
- a conveyor belt (<NUM>) constituting a closed loop and configured to transfer the material inside the treatment room from the first end of the treatment room to a second end of the treatment room, and
- an outlet (<NUM>) configured to remove the temperature treated material from the second end of the treatment room,
wherein the interior room (<NUM>) contains a drive mechanism configured to drive the conveyor belt, the drive mechanism comprising a first wheel (<NUM>) supporting the conveyor belt at the first end of the treatment room and a second wheel (<NUM>) supporting the conveyor belt at the second end of the treatment room, characterized in that the wall structures are configured to exclude a room (<NUM>) being between the first and second wheels out from the interior room so that the wall structures are configured to constitute a first tubular part (<NUM>) containing a first part of the conveyor belt being between the first and second wheels and a second tubular part (<NUM>) containing a second part of the conveyor belt being between the first and second wheels, the first tubular part forming at least a part of the treatment room.