KR20230043310A - Manufacturing method of high-quality wood pellets using semi-Carbonized forest biomass and wood tar and high-quality pellets using the same - Google Patents

Abstract

The present invention relates to a torrefaction apparatus and high-quality pellets using wood tar. A method for manufacturing high-quality wood pellets using semi-carbonized forest biomass and wood tar is provided. To this end, the method comprises: a step (S100) of injecting a portion of unused forest biomass into a rotary kiln device (100) and processing the portion into wood flour; steps (S110, S120) in which the rotary kiln device (100) discharges carbonized fuel and wood tar as a by-product thereof; a step (S160) in which the wood flour, the carbonized fuel, and the wood tar are mixed in a mixing device; and a step (S170) in which a molding machine molds the mixture of the wood flour, the carbonized fuel, and the wood tar into pellets. According to the present invention, the amount of fossil fuel used can be reduced by an increase in a mixed firing rate.

Description

Manufacturing method of high-quality wood pellets using semi-Carbonized forest biomass and wood tar and high-quality pellets using the same}

The present invention relates to wood pellets, and more particularly, to a method for producing high-quality pellets using torrefied forest biomass and wood tar, which have performance improvement effects such as increased calorific value, improved product strength, and reduced pollutant emissions. And high-quality pellets using it, and it is the result of 'high-efficiency eco-friendly solid fuel commercialization through up-cycling of waste resources', a small and medium-sized environmental enterprise commercialization support project of the Ministry of Environment (Korea Environmental Industry and Technology Institute).

In recent years, the supply and use of boilers that can use pellet fuel are increasing day by day, centering on general farms, livestock farms, dairy farms, and factories that use boilers for home or small-scale business.

Pellets used as fuel for boilers are fuel made by crushing sawdust or wood by thinning and then compressing them. They emit less carbon dioxide than fossil fuels such as coal or oil and have less residue after combustion, so their use is rapidly increasing. It is increasing. In particular, in rural areas where the supply of city gas is poor, or in large-scale barns or dairy farms, the use of pellets, which are cheaper than petroleum products, is increasingly being used for heating.

Currently, the main use of pellets is for thermal/biomass combined-fired power plants, where more than 1.5 million tons are used annually, and most of the pellets used as fuel for power generation depend on imported wood pellets. Most of the pellets produced in Korea are used for household/industrial purposes, and the annual production is about 200,000 tons.

In order to enter the pellet market for power generation of domestic pellets, it is necessary to secure cheap wood pellet manufacturing in order to secure price competitiveness of domestic pellets against imported wood pellets with low unit prices.

Therefore, it is necessary to develop production technology for wood pellets used as fuel for domestic thermal/biomass combined-firing power plants, such as branch wood and root wood, which are forest by-products (unused forest biomass) that have been previously used as raw materials for waste treatment or compost.

In addition, when forest biomass is pyrolyzed in a pyrolysis furnace, wood tar is inevitably generated. This wood tar is a black oily substance that is highly viscous and hardens. Since this wood tar was pointed out as a cause of clogging of the pyrolysis furnace, it was periodically removed and disposed of separately.

1. Republic of Korea Patent Publication No. 10-2013-0090600 (torrefied pellet manufacturing apparatus and method and torrefied pellets manufactured using the same), 2. Republic of Korea Patent Registration No. 10-1308397 (Method for producing high calorific value wood-based solid fuel by low-temperature torrefaction method), 3. Republic of Korea Patent Publication No. 10-2021-0029542 (high calorific value wood-based solid fuel).

Therefore, the present invention has been made to solve the above problems, and the problem to be solved by the present invention is torrefaction of unused forest biomass with microwaves, and wood tar generated as a by-product during pyrolysis is mixed with forest biomass. To provide a method for producing high-quality pellets and high-quality pellets using the same.

However, the technical problems to be achieved in the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clear to those skilled in the art from the description below. You will be able to understand.

In order to achieve the above technical problem, inputting a portion of the unused forest biomass into the rotary kiln device 100 and processing a portion of the forest biomass into wood flour (S100); The rotary kiln device 100 discharging torrefied fuel and wood tar as a by-product (S110, S120); mixing the wood powder, the torrefied fuel, and the wood tar in a mixing device (S160); and forming pellets from a mixture of the wood flour, the torrefied fuel, and the wood tar by a molding machine (S170); a method for producing high-quality pellets using torrefied forest biomass and wood tar is provided .

In addition, the wood powder processing step (S100) includes a step of sorting iron pieces from the forest biomass by a magnetic separator (S130); and pulverizing the forest biomass into a predetermined particle size by a crusher to produce wood flour (S140).

In the mixing step (S160), 3 to 20 parts by weight of the wood tar based on 100 parts by weight of the torrefied fuel; And 90 to 120 parts by weight of the wood powder; is put together.

In addition, in the molding step (S170), the pellets are molded to a length of 30 mm to 50 mm.

In addition, the rotary kiln device 100 further includes a microwave device 150 for emitting microwaves 160 for torrefaction.

In addition, the microwave 160 has a frequency range of 300 MHz to 300 GHz, the rotary kiln device 100 is heated in the range of 200 ° C to 250 ° C, and the thermal decomposition time of the rotary kiln device 100 is 10 minutes to It is in the 30 minute range.

As another embodiment, the object of the present invention as described above can also be achieved by high-quality pellets using forest biomass and wood tar, which are characterized in that they are produced by the above-described manufacturing method.

According to one embodiment of the present invention, when biomass fuel and coal fuel are co-firing, the biomass co-firing rate can be increased.

In addition, the amount of fossil fuel used can be reduced by increasing the mixed combustion rate.

In addition, the manufactured torrefied pellets have performance improvement effects such as improvement in calorific value, improvement in product strength, and reduction in pollutant emissions.

Due to the viscosity and cohesiveness of wood tar, the length of the pellets can be molded sufficiently long, and the density of the pellets can also be increased.

In addition, due to the tackiness of wood tar, generation of fine wood powder can be minimized and durability of the pellets can be increased.

However, the effects obtainable in the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below. You will be able to.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical idea of the present invention, the present invention is the details described in such drawings should not be construed as limited to
1 is a side view of a torrefaction apparatus for forest biomass using microwaves according to the present invention;
Figure 2 is a flow chart of a method for producing high-quality pellets using torrefied forest biomass and wood tar according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, since the description of the present invention is only an embodiment for structural or functional description, the scope of the present invention should not be construed as being limited by the embodiments described in the text. That is, since the embodiment can be changed in various ways and can have various forms, it should be understood that the scope of the present invention includes equivalents capable of realizing the technical idea. In addition, since the object or effect presented in the present invention does not mean that a specific embodiment should include all of them or only such effects, the scope of the present invention should not be construed as being limited thereto.

The meaning of terms described in the present invention should be understood as follows.

Terms such as "first" and "second" are used to distinguish one component from another, and the scope of rights should not be limited by these terms. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element. It should be understood that when an element is referred to as “connected” to another element, it may be directly connected to the other element, but other elements may exist in the middle. On the other hand, when an element is referred to as being “directly connected” to another element, it should be understood that no intervening elements exist. Meanwhile, other expressions describing the relationship between components, such as “between” and “immediately between” or “adjacent to” and “directly adjacent to” should be interpreted similarly.

Singular expressions should be understood to include plural expressions unless the context clearly dictates otherwise, and terms such as “comprise” or “having” refer to a described feature, number, step, operation, component, part, or It should be understood that it is intended to indicate that a combination exists, and does not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

All terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless defined otherwise. Terms defined in commonly used dictionaries should be interpreted as consistent with meanings in the context of related art, and cannot be interpreted as having ideal or excessively formal meanings unless explicitly defined in the present invention.

Configuration of the embodiment

Hereinafter, the configuration of a preferred embodiment will be described in detail with reference to the accompanying drawings. 1 is a side view of a torrefaction apparatus for forest biomass using microwaves according to the present invention. In the present invention, unused forest biomass may be a forest by-product (eg, branches and root necks, etc.).

The torrefaction apparatus of the present invention can be applied to a known rotary kiln apparatus 100. The input unit 10 may be a hopper device provided on one side into which unused forest biomass is input.

The reactor 120 has a rotatable cylindrical closed structure, and can maintain a vacuum therein. Forest biomass inside the reactor 120 is heated to a high temperature without oxygen to cause a thermal decomposition reaction. The thermal decomposition time in the reactor 120 ranges from 10 minutes to 30 minutes. It can be operated in the range of 10 to 30 minutes for optimal production efficiency and torrefaction, preferably 20 to 30 minutes.

The driving device 130 may rotate the cylindrical reactor 120 at a constant speed or rotate forward and backward in a range of 180° to 360°.

The burner device 140 is installed around the reactor 120 to heat the reactor 120 up to 600°C. The burner device 140 may be a gas burner or an oil burner. In the embodiment of the present invention, the burner device 140 heats in the range of 200 ° C to 250 ° C for torrefaction. Through a number of experiments, it was confirmed that 200 ° C. to 250 ° C. causes the optimal torrefaction reaction during the thermal decomposition process for about 30 minutes.

The microwave device 150 is provided on the inner surface of the reactor 120, rotates together with the reactor 120, and emits microwaves 160 toward the inside of the reactor 120. The microwave 160 has a frequency range of 300 MHz to 300 GHz. Preferably, it can be 2 ~ 3 GHz, and the microwave device 150 can be a magnetron, and is insulated around the perimeter.

The rotation cable 190 is connected between the microwave device 150 and the AC power supply 180 to supply necessary power. When the driving device 130 rotates forward and backward in the range of 180° to 360°, the rotation cable 190 may be an electric wire having a length corresponding to the circumferential length of the minimum reaction furnace 120 . Any length sufficient to supply power is sufficient if the rotation of the reactor 120 is not obstructed.

Optionally, when the driving device 130 rotates at a constant speed, the rotating cable 190 is a slip-type ring electrode installed along the outer circumference of the reactor 120. Power may be supplied to the inside of the rotating reactor 120 through a known slip-type ring electrode.

The discharge device 170 discharges the torrefied forest biomass by the microwave 160 . The torrefied forest biomass is formed into wood pellets in a pellet forming machine.

Operation of the embodiment

Hereinafter, the operation of the preferred embodiment will be described in detail with reference to the accompanying drawings. Figure 2 is a flow chart of a method for producing high-quality pellets using torrefied forest biomass and wood tar according to an embodiment of the present invention. As shown in FIG. 2, first, a portion of unused forest biomass is put into a hopper (S100), and the rest is processed into wood flour. Unused forest biomass can be a by-product of forest trees (eg, branches and root necks), and a hopper, which is an input device, is a well-known machine.

The microwave 160 causes a torrefaction reaction while penetrating deep into the forest biomass. That is, it is different from a process in which only the outer surface of forest biomass is pyrolyzed by the burner device 140. In one embodiment of the present invention, a thermal decomposition reaction occurs on the outer surface of the forest biomass at a low temperature (200 ° C. to 250 ° C.) for about 30 minutes, and heat is generated from the inside by the microwave 160, which causes a torrefaction reaction at the same time. takes place in a complex way

Next, the rotary kiln device 100 discharges torrefied fuel and wood tar as a by-product, respectively (S110 and S120). Wood tar is an inevitably generated by-product when unused biomass is pyrolyzed in a pyrolysis furnace. This wood tar is a black oily substance that is highly viscous and hardens.

On the other hand, in the wood flour processing step (S100), after the magnetic separator selects the iron pieces from the forest biomass (S130), the crusher grinds the forest biomass into a predetermined particle size to produce wood flour (S140). The magnetic separator has a ferromagnetic force of 3,000 to 5,000 Gauss. The grinder may be a mixer, grinder, blender, etc., and the produced wood flour has a size ranging from 1 mm to 8 mm.

Then, the mixing device mixes wood powder, torrefied fuel and wood tar (S160). At this time, 3 to 20 parts by weight of wood tar based on 100 parts by weight of torrefied fuel; And 90 to 120 parts by weight of wood flour are added together. Less than 3 parts by weight of wood tar is difficult to expect the adhesion performance of wood powder, and if it exceeds 20 parts by weight, the movement and moldability of the material deteriorates due to the viscosity of wood tar. Wood flour is added in the same or similar weight as torrefied fuel.

In addition, in the mixing step (S160), the mixing device is preheated to 30 ℃ ~ 50 ℃. Cooling of wood tar can be prevented by preheating the mixing device. An electric heater or a hot water pipe may be disposed in the mixing device for preheating.

Then, the molding machine forms and completes high-quality pellets from a mixture of wood flour and wood tar (S170). At this time, the finished pellet has a cylindrical shape and has a length of 30 mm to 50 mm. Considering that conventional pellets have a length of about 20 mm, a length of 30 mm to 50 mm can be considered a sufficient elongated pellet.

Although the forest biomass of the present invention has been described mainly on unused forest biomass, it has been described as a herbaceous system (rice straw, corn stalk, barley stalk, wheat straw, pulp, palm leaf, etc.) or woody system, and a mixture of herbaceous and woody systems. Forest biomass in the form is also possible.

Detailed descriptions of the preferred embodiments of the present invention disclosed as described above are provided to enable those skilled in the art to implement and practice the present invention. Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the scope of the present invention. For example, those skilled in the art can use each configuration described in the above-described embodiments in a way of combining each other. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention. Accordingly, the above detailed description should not be construed as limiting in all respects and should be considered as illustrative. The scope of the present invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present invention are included in the scope of the present invention. The invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, claims that do not have an explicit citation relationship in the claims may be combined to form an embodiment or may be included as new claims by amendment after filing.

10: input unit,
100: rotary kiln device,
120: reaction furnace,
130: driving device,
140: burner device,
150: microwave device,
160: microwave,
170: discharge device,
180: power supply,
190: rotating cable.

Claims (7)

Putting some of the unused forest biomass into the rotary kiln device 100 and processing some of it into wood flour (S100);
The rotary kiln device 100 discharging torrefied fuel and wood tar as a by-product (S110, S120);
mixing the wood powder, the torrefied fuel, and the wood tar in a mixing device (S160); and
A method for producing high-quality pellets using torrefied forest biomass and wood tar, characterized in that it comprises: forming pellets from a mixture of the wood flour, the torrefied fuel, and the wood tar by a molding machine (S170).
According to claim 1,
In the wood flour processing step (S100),
Selecting iron pieces from the forest biomass by a magnetic separator (S130); and
A method for producing high-quality pellets using torrefied forest biomass and wood tar, comprising the step of pulverizing the forest biomass into a predetermined particle size by a grinder to produce wood flour (S140).
According to claim 1,
In the mixing step (S160), for 100 parts by weight of the torrefied fuel
3 to 20 parts by weight of the wood tar; and
90 to 120 parts by weight of the wood flour; a method for producing high-quality pellets using torrefied forest biomass and wood tar, characterized in that added together.
According to claim 1,
In the forming step (S170), the pellets are formed to a length of 30 mm to 50 mm. Method for producing high-quality pellets using torrefied forest biomass and wood tar.
According to claim 1,
The rotary kiln device 100 is a method for producing high-quality pellets using torrefied forest biomass and wood tar, characterized in that it further comprises a microwave device 150 for radiating microwaves 160 for torrefaction.
According to claim 5,
The microwave 160 has a frequency range of 300 MHz to 300 GHz,
The rotary kiln device 100 is heated in the range of 200 ° C to 250 ° C,
The method of producing high-quality pellets using torrefied forest biomass and wood tar, characterized in that the thermal decomposition time of the rotary kiln device 100 is in the range of 10 minutes to 30 minutes.
A high-quality pellet using forest biomass and wood tar, characterized in that it is produced by the manufacturing method according to any one of claims 1 to 6.

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