Biomass solid fuel manufacturing device, and biomass solid fuel manufacturing method

Abstract

The present invention pertains to a biomass solid fuel manufacturing device provided with a rotary kiln, wherein a kiln body of the rotary kiln is provided with: a first heating zone which has a plurality of first lifter blades and heats biomass molded bodies; and a second heating zone which has a plurality of second lifter blades and further heats the biomass molded bodies heated in the first heating zone. The plurality of first lifter blades and the plurality of second lifter blades are configured such that the quantity of the biomass molded bodies scraped up per unit length of the kiln body is higher in the first heating zone than in the second heating zone.

Description

Apparatus for producing biomass solid fuel, and method for producing biomass solid fuel

[0001] This disclosure relates to a biomass solid fuel manufacturing apparatus and a biomass solid fuel manufacturing method.

[0002] A technology is known for producing biomass solid fuel by carbonizing a biomass molded body, formed from raw biomass, in an externally heated rotary kiln. Since biomass contains moisture, steam is generated from the biomass at the beginning of heating. This can cause moisture to adhere to the biomass molded body in the unheated zone, potentially accelerating its collapse. Therefore, Patent Document 1 proposes suppressing collapse during production by providing spiral blades in the unheated zone of the rotary kiln.

[0003] Japanese Patent Publication No. 2020-33396

[0004] This disclosure provides a biomass solid fuel manufacturing apparatus capable of suppressing collapse during the production of biomass solid fuel, and a method for manufacturing biomass solid fuel.

[0005] One aspect of the present disclosure is a biomass solid fuel production apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, wherein the plurality of first lifter blades and the plurality of second lifter blades are configured such that the amount of biomass molded body scraped up per unit length of the kiln body is greater in the first heating zone than in the second heating zone, thereby providing a biomass solid fuel production apparatus.

[0006] When a biomass molded body is heated inside a kiln, the water evaporates. If the atmosphere inside the kiln and the temperature of the biomass molded body are sufficiently high, the evaporated water will be discharged from the kiln as gas without condensation. On the other hand, if the atmosphere inside the kiln or the temperature of the biomass molded body is not sufficiently high, the evaporated water will condense. When the condensed water adheres to the biomass molded body, it expands, causing a decrease in strength.

[0007] When biomass solid fuel is produced using the above-described manufacturing apparatus, the temperature of the biomass molded body tends to be lower and the water vapor concentration higher in the first heating zone than in the second heating zone. In the above-described manufacturing apparatus, the multiple first lifter blades and multiple second lifter blades are configured such that the amount of biomass molded body raked up per unit length of the kiln body is greater in the first heating zone than in the second heating zone. In the first heating zone, the biomass molded body is raked up by the multiple first lifter blades, and the biomass molded body and gas are thoroughly mixed. As a result, the biomass molded body is heated with high uniformity, and the adhesion of condensation water to the biomass molded body is suppressed. Therefore, the reduction in strength of the biomass molded body due to the adhesion of condensation water can be suppressed. In addition, in the second heating zone, excessive raking can be suppressed, and pulverization due to the falling of the raked-up biomass molded body can be suppressed. The above-described manufacturing apparatus can suppress collapse when producing biomass solid fuel due to these factors.

[0008] One aspect of the present disclosure provides a biomass solid fuel manufacturing apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, and the plurality of first lifter blades include a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion that is inclined in the counter-rotation direction closer to the center of rotation than the base portion, thereby providing a biomass solid fuel manufacturing apparatus.

[0009] When biomass solid fuel is produced using the above-described manufacturing apparatus, the temperature of the biomass molded body tends to be lower and the water vapor concentration higher in the first heating zone than in the second heating zone. As a result, in the first heating zone, condensed moisture adheres to the biomass molded body more easily than in the second heating zone, leading to a decrease in the strength of the biomass molded body. The above-described manufacturing apparatus has inclined sections in the first heating zone where multiple first lifter blades are tilted in the counter-rotation direction closer to the center of rotation than the base. As a result, the impact when the biomass molded body, which has been lifted by the first lifter blades, falls to the bottom of the kiln body can be reduced. This suppresses the pulverization of the biomass molded body due to the impact of the fall. Therefore, the above-described manufacturing apparatus can suppress collapse when producing biomass solid fuel.

[0010] One aspect of the present disclosure provides a biomass solid fuel manufacturing apparatus equipped with a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, and satisfies one or both of the following (a) and (b): (a) When LF is the average value of the lengths of the plurality of first lifter blades along the direction from the inner circumferential surface of the kiln body toward the center of rotation, and LS is the average value of the lengths of the plurality of second lifter blades along the said direction, LF > LS. (b) The number of the plurality of first lifter blades is greater than the number of the plurality of second lifter blades.

[0011] When biomass solid fuel is produced using the above-described manufacturing apparatus, the temperature of the biomass molded body tends to be lower and the water vapor concentration higher in the first heating zone than in the second heating zone. The above-described manufacturing apparatus has multiple first lifter blades that satisfy one or both of the above conditions (a) and (b). Therefore, in the first heating zone, the biomass molded body is easily scraped up sufficiently. As a result, the biomass molded body and gas are thoroughly mixed. Consequently, the biomass molded body is heated with high uniformity, and the adhesion of condensation water to the biomass molded body can be suppressed. Furthermore, in the second heating zone, excessive scraping can be suppressed, and pulverization caused by the falling of the scraped-up biomass molded body can be suppressed. Due to these factors, the above-described manufacturing apparatus can suppress collapse when producing biomass solid fuel.

[0012] One aspect of this disclosure is a method for producing a biomass solid fuel using any of the above-described manufacturing apparatus, comprising the steps of introducing the biomass molded body into the rotary kiln and heating the biomass molded body in heating zones including the first heating zone and the second heating zone to carbonize it.

[0013] In the above manufacturing method, biomass solid fuel is produced from biomass molded bodies using one of the above-described manufacturing apparatuses. In each of the above-described manufacturing apparatuses, the adhesion of condensation water to the biomass molded bodies is suppressed in the first heating zone, thereby suppressing a decrease in the strength of the biomass molded bodies. In the second heating zone, excessive scraping is suppressed, and pulverization associated with the falling of the scraped biomass molded bodies is suppressed. By these factors, the above manufacturing method can suppress collapse during the production of biomass solid fuel.

[0014] According to this disclosure, it is possible to provide a biomass solid fuel manufacturing apparatus and a biomass solid fuel manufacturing method that can suppress the collapse of biomass solid fuel during its production.

[0015] This is a cross-sectional view showing the operating state of a biomass solid fuel production apparatus. This is a diagram showing the temperature distribution during the operation of the biomass solid fuel production apparatus. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an enlarged view of the bent blade in Figure 3. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an enlarged view of the bent blade in Figure 5. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the second heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the first heating zone of the kiln body. This is a radial cross-sectional view showing an example of the second heating zone of the kiln body. Figure 22(A) shows an example of the arrangement of multiple first lifter blades. Figure 22(B) shows an example of the arrangement of non-bent blades. Figure 22(C) shows another example of the arrangement of non-bent blades. Figure 23(A) shows an example of the structure of the first lifter blade or the second lifter blade. Figure 23(B) shows an example of the structure of a bent blade. Figure 23(C) shows another example of the structure of a bent blade.

[0016] Embodiments of the present disclosure will be described below, with reference to the drawings as appropriate. However, the following embodiments are illustrative for the purpose of explaining the present disclosure and are not intended to limit the present disclosure to the following. In the description, the same reference numerals will be used for elements that are the same or have the same function, and redundant explanations will be omitted as appropriate. Also, positional relationships such as up, down, left, and right will be based on the orientation of the reference numerals in the drawings unless otherwise specified. The dimensional ratios of each element are not limited to the ratios shown. In the description, the symbol "~" used in numerical ranges indicates a numerical range that includes the upper and lower limits. For example, "X~Y" indicates a numerical range of "X or more and Y or less". Numerical ranges in which the upper and / or lower limits of a numerical range are replaced with the values ​​described in the embodiments are also included in the present disclosure. If a numerical range is illustrated with only the upper limit or only the lower limit, a numerical range combining the numerical range with only the upper limit and the numerical range with only the lower limit is also included in the present disclosure. Numerical ranges in which the upper and / or lower limits of one numerical range are replaced with the upper and / or lower limits of another numerical range are also included in the present disclosure. This disclosure also includes applying the concepts described in one embodiment to other embodiments.

[0017] [Biomass Solid Fuel Manufacturing Apparatus] The following describes the common features of each embodiment listed below. The biomass solid fuel manufacturing apparatus is an apparatus for manufacturing biomass solid fuel from biomass molded bodies and includes a rotary kiln equipped with a plurality of lifter blades. The rotary kiln may be an externally heated rotary kiln or a directly heated rotary kiln. An externally heated rotary kiln is a type that comprises a kiln body (inner cylinder) and an outer cylinder, and indirectly heats the biomass molded bodies introduced into the kiln body by a heating fluid flowing between the kiln body and the outer cylinder. A directly heated rotary kiln is a type that directly heats the biomass molded bodies introduced into the rotary kiln by the combustion heat of a burner installed inside the rotary kiln.

[0018] Biomass molded products are made by molding crushed biomass into pellets or briquettes, and are sometimes referred to as WP (White Pellet). The moisture content of the biomass molded products may be 1 to 10% by mass, or 2 to 8% by mass. The type of biomass is not particularly limited, and both woody and herbaceous biomass can be used. The tree species and parts of the biomass are also not particularly limited. Examples of biomass include rubber trees, acacia, Dipterocarpaceae tree species, radiata pine, larch, spruce, and birch. Other examples of biomass include Douglas fir, Western hemlock, cedar, cypress, Scots pine, old almond wood, almond shells, walnut shells, sago palm, EFB (empty fruit clusters of palm oil processing residue), and meranti. One of these may be used alone, or two or more may be used in combination.

[0019] The diameter of the pelletized or briquette-shaped biomass molded body may be 2 mm or more, 3 mm or more, or 4 mm or more, from the viewpoint of improving handling. The diameter of the pelletized or briquette-shaped biomass molded body may be 20 mm or less, 15 mm or less, or 10 mm or less, from the viewpoint of facilitating sufficient carbonization to the interior. The length of the briquette-shaped biomass molded body may be 5 mm or more, 8 mm or more, or 10 mm or more, from the viewpoint of improving handling. The length of the briquette-shaped biomass molded body may be 100 mm or less, 60 mm or less, or 40 mm or less, from the viewpoint of facilitating sufficient carbonization to the interior. The shape and size of the biomass solid fuel obtained by carbonizing the biomass molded body may be the same as that of the biomass molded body.

[0020] The properties of the biomass solid fuel are not particularly limited. For example, the fuel ratio (fixed carbon / volatile matter) may be 0.2 to 0.8, the anhydrous base higher heating value may be 4800 to 7000 kcal / kg, the molar ratio of oxygen to carbon (O / C) may be 0.1 to 0.7, and the molar ratio of hydrogen to carbon (H / C) may be 0.8 to 1.3.

[0021] The strength (DU) of the biomass solid fuel may be 80 or higher, 82 or higher, or 85 or higher. Such biomass solid fuels are easy to handle because they do not easily disintegrate. The strength (DU) is calculated using the following formula (1) in accordance with the American agricultural and industrial standard ASAE S 269.4 and the German industrial standard DIN EN 15210-1. In formula (1), m0 is the weight of the sample before rotation, and m1 is the weight of the sieved sample after rotation. A plate sieve with a circular hole diameter of 3.15 mm is used. DU = (m1 / m0) × 100 (1)

[0022] The kiln body of a rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone. The plurality of first lifter blades and the plurality of second lifter blades may be configured such that the amount of biomass molded body raked up per unit length of the kiln body differs between the first heating zone and the second heating zone. The unit length of the kiln body is the length along the rotation axis of the kiln body, and may be shorter than the first heating zone and the second heating zone. The unit length of the kiln body may be, for example, 1 m.

[0023] The amount of biomass molded material raked up refers to the amount of biomass molded material raked up by multiple first lifter blades or multiple second lifter blades as the kiln body rotates. The relative amounts of raked up per unit length are determined by the amount of biomass molded material raked up from the bottom of the kiln body when the kiln body rotates once. For example, increasing the length of the lifter blades along the radial direction of the kiln body can increase the amount of biomass molded material raked up. The amount of biomass molded material raked up can be adjusted by changing the shape and / or size of the lifter blades.

[0024] The multiple first lifter blades may all be composed of lifter blades of the same shape, or they may be composed of multiple types of lifter blades with different shapes. The multiple second lifter blades may all be composed of lifter blades of the same shape, or they may be composed of multiple types of lifter blades with different shapes. At least one of the multiple first lifter blades may have the same shape as at least one of the multiple second lifter blades.

[0025] Multiple first lifter blades and / or multiple second lifter blades may or may not include a curved blade. A curved blade is defined as a blade that includes a curved portion when viewed in the radial cross-section of the kiln body. A curve includes both a straight bend and an arc-shaped bend. A curved blade may have a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion that includes a portion closer to the center of rotation than the base portion and inclined in the direction of rotation or in the counter-rotation direction. The counter-rotation direction means the direction of rotation opposite to the direction of rotation. "A portion inclined in the direction of rotation" means a portion of the curved blade that, when viewed from the base end (the connection point with the inner circumferential surface of the kiln body) toward the tip, is inclined more toward the direction of rotation than the radial direction of the kiln body. "A portion inclined in the direction of counter-rotation" means a portion of the curved blade that, when viewed from the base end toward the tip, is inclined more toward the direction of counter-rotation than the radial direction of the kiln body. The inclined portion may include either a portion inclined in the direction of rotation or a portion inclined in the counter-rotation direction, or both. The bent blade may have a projection in the direction of rotation.

[0026] <First Embodiment> In the biomass solid fuel production apparatus according to the first embodiment, the plurality of first lifter blades and the plurality of second lifter blades are configured such that the amount of biomass molded body scraped up per unit length of the kiln body is greater in the first heating zone than in the second heating zone. The plurality of first lifter blades may have a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion including a portion that is inclined in the rotational direction closer to the center of rotation than the base portion.

[0027] Figure 1 schematically shows the operating state of a biomass solid fuel production apparatus. The production apparatus 100 in Figure 1 comprises an externally heated rotary kiln 10 having a kiln body 12 (inner cylinder) and an outer cylinder 14, an introduction section 50 for introducing biomass molded bodies 51 into the kiln body 12 of the rotary kiln 10, and an outlet section 30 for discharging biomass solid fuel 53 from the kiln body 12 of the rotary kiln 10. The introduction section 50 only needs to have a configuration that can transport the biomass molded bodies 51, and may, for example, be equipped with a conveyor.

[0028] The kiln body 12 in the rotary kiln 10 has a predetermined inner diameter R and is rotatably supported by rollers 15 and 16. Biomass molded bodies 51 are introduced into the kiln body 12 from the inlet 50. The rotation axis of the kiln body 12 is slightly inclined with respect to the horizontal, with the inlet 50 side being higher than the outlet 30 side. Therefore, the biomass molded bodies 51 introduced into the kiln body 12 are agitated by the rotation of the kiln body 12 and move from the inlet 50 side to the outlet 30 side. In Figure 1, the biomass molded bodies 51 move from left to right within the kiln body 12. In this specification, the terms "upstream" and "downstream" may be used based on the direction of movement of such biomass molded bodies 51. The biomass molded bodies 51 move from the upstream side to the downstream side inside the rotary kiln 10 (kiln body 12).

[0029] In addition to the biomass molded body 51, nitrogen gas (N) is also present inside the kiln body 12 of the rotary kiln 10. ２) may also be introduced. Nitrogen gas also moves from the upstream side to the downstream side of the kiln body 12 together with the biomass molded body 51. The biomass molded body 51 is carbonized by heating inside the kiln body 12 to become biomass solid fuel 53. The biomass solid fuel 53 is taken out from the outlet valve 32 provided in the outlet section 30. When the biomass molded body 51 is heated inside the kiln body 12, combustible components are generated from the biomass molded body 51 in addition to water. The combustible gas thus produced passes through the gas outlet 33 provided in the outlet section 30, flows through the flow path 41, and is introduced into the combustion furnace 40. The combustion furnace 40 may be, for example, a boiler. The combustion furnace 40 is equipped with a burner 44, and the combustible gas is introduced into the burner 44 together with an oxygen-containing gas such as air and combusted. The exhaust gas produced in the combustion furnace 40 flows through the flow path 42 and is introduced into the hot gas flow path 17 from the gas introduction section 43 provided in the outer cylinder 14.

[0030] The kiln body 12 has a first unheated zone Z1, a first heated zone H1, a second heated zone H2, and a second unheated zone Z2 in this order along the axis of rotation. The first unheated zone Z1, the first heated zone H1, the second heated zone H2, and the second unheated zone Z2 are arranged in this order from upstream to downstream of the kiln body 12. That is, the first unheated zone Z1 is located furthest upstream, and the second unheated zone Z2 is located furthest downstream.

[0031] In the first heating zone H1 and the second heating zone H2, an outer cylinder 14 is provided around the outer circumference of the kiln body 12. The outer cylinder 14 forms a hot gas passage 17 that indirectly heats the kiln body 12. Hot gas is supplied to the hot gas passage 17 formed by the outer cylinder 14 from the gas inlet 43. The hot gas is not limited to exhaust gas from the combustion furnace 40, but may be exhaust gas generated from combustion equipment such as a boiler different from the combustion furnace 40. The temperature of the hot gas introduced from the gas inlet 43 may be, for example, 300 to 1000°C. The hot gas heats the kiln body 12 by flowing through the hot gas passage. The hot gas that has heated the kiln body 12 is discharged to the outside from the outer cylinder 14 as exhaust gas EG.

[0032] The biomass molded body 51 is introduced from the introduction section 50 into the first unheated zone Z1 of the kiln body 12 of the rotary kiln 10. The outer circumference of the first unheated zone Z1 is not provided with an outer cylinder 14. Therefore, the biomass molded body 51 does not need to be heated substantially in the first unheated zone Z1. In the first unheated zone Z1, a spiral blade may be provided on the inner circumferential surface 13 of the kiln body 12 to promote the downstream movement of the biomass molded body 51. The spiral blade is a spiral-shaped blade attached to the inner circumferential surface 13 of the kiln body 12. Compared to a lifter blade, the spiral blade can reduce the amount of biomass molded body 51 that is scraped up. Therefore, the collapse of the biomass molded body 51 can be suppressed.

[0033] The biomass molded body 51 that has passed through the first unheated zone Z1 is introduced into the first heated zone H1. In the first heated zone H1, the biomass molded body 51 is heated by heat transfer from the hot gas flowing through the hot gas channel 17. When the biomass molded body 51 is heated, the water evaporates before it can be carbonized. The evaporated water, along with the biomass molded body 51, flows through the kiln body 12 from upstream to downstream.

[0034] Figure 2 shows the temperature distribution of the biomass molded body 51 (biomass solid fuel 53) inside the kiln body 12. The horizontal axis P is the position along the rotation axis direction inside the kiln body 12, and the vertical axis is the temperature T of the biomass molded body 51 (biomass solid fuel 53) inside the kiln body 12. The temperature To in the first unheated zone Z1 may be approximately the same as the ambient temperature, for example, 0 to 40°C. The ambient temperature in the first heated zone H1 gradually increases as it approaches the second heated zone H2 located downstream of the first heated zone H1. That is, in the first heated zone H1, the temperature of the biomass molded body 51 in the kiln body 12 rises from temperature To to temperature Td. Temperature Td is, for example, the dew point T inside the kiln body 12. ｄｅｗ It is acceptable if the temperature of the biomass molded body 51 is the dew point T. ｄｅｗIn the following region, the moisture evaporated from the biomass molded body 51 is likely to condense. When the condensed water adheres to the biomass molded body 51, the biomass molded body 51 expands, and the strength of the biomass molded body 51 and the biomass solid fuel 53 tends to decrease.

[0035] The dew point T in the kiln body 12 ｄｅｗ can be obtained as follows. The dew point T ｄｅｗ and the water vapor partial pressure (P Ｈ２Ｏ ) The Teten's formula of the following formula (2) is known as a formula showing the relationship.

[0036] The water vapor partial pressure (P Ｈ２Ｏ ) of the kiln body 12 can be obtained, for example, by the following formula.

[0037] In the above formula (3), Q represents the flow rate [Nm ３ / h] of the inert gas introduced into the kiln body 12, P ０ represents the atmospheric pressure [hPa], m represents the introduction amount [ton / h] of the biomass molded body 51, and a represents the moisture content [wt%] of the biomass molded body 51. Based on these measured values or estimated values, the water vapor partial pressure (P Ｈ２Ｏ ) of the kiln body 12 is calculated. From the calculated water vapor partial pressure (P Ｈ２Ｏ ) and the Teten's formula of formula (2), the dew point T ｄｅｗ in the kiln body 12 can be obtained. The method for obtaining the dew point T ｄｅｗ in the kiln body 12 is not particularly limited, and a graph showing the relationship between the saturated water vapor pressure and the temperature may be used, or a saturated vapor table may be used.

[0038] Among the kiln bodies 12 of the rotary kiln 10, the length L1 [m] until the dew point T ｄｅｗ is reached may be obtained by the following formula (4).

[0039] In formula (4), L is the total length [m] of the heating zone. In the present embodiment, the total length of the heating zone is the sum of the lengths of the first heating zone H1 and the second heating zone H2. Qst is the position where the biomass molded body 51 starts heating in the kiln body 12 (temperature To) to the dew point T ｄｅｗQwt is the amount of heat [kcal / h] received while moving to the position. Qwt is the amount of heat received by the biomass molded body 51 from the heating start position (temperature To) in the kiln body 12 to the dew point T. ｄｅｗ Qs is the amount of heat [kcal / h] absorbed by the water contained in the biomass molded body 51 while it is moving to position Tm. Qs is the amount of heat [kcal / h] absorbed by the biomass molded body 51 while it is moving from the heating start position (temperature To) to the heating end position (temperature Tm). Qw is the amount of heat [kcal / h] absorbed by the water contained in the biomass molded body 51 while it is moving from the heating start position (temperature To) to the heating end position (temperature Tm). Temperature To and temperature Tm are the temperatures of the biomass molded body 51 (biomass solid fuel 53) inside the kiln body 12, as shown in Figure 2.

[0040] In Figure 2, if the length of the first heating zone H1 is L1, then the temperature Td in Figure 2 = dew point T ｄｅｗ This means that the first heating zone H1 heats the biomass molded body 51 to the dew point T ｄｅｗ This is the region that is heated until it reaches the dew point T. In addition, the second heating zone H2 heats the biomass molded body 51 (biomass solid fuel 53) until it reaches the dew point T. ｄｅｗ This region is heated to a higher temperature and carbonizes. Qst, Qs, Qwt, and Qw in equation (4) may be calculated using the following equations (5), (6), (7), and (8).

[0041] Qst = Cs × (T ｄｅｗ -To) x W x (1-a / 100) (5) Qs = Cs x (Tm-To) x W x (1-a / 100) (6) Qwt = (Hgt-Hw) x W x a / 100 (7) Qw = (Hg-Hw) x W x a / 100 (8)

[0042] In equations (5) and (6) above, Cs is the specific heat of the biomass molded body 51 [kcal / (kg·°C)], W is the supply rate of the biomass molded body 51 [kg / h], and a is the moisture content [wt%] of the biomass molded body 51. To, Tm, T ｄｅｗAs stated above, in equation (7) above, Hw is the enthalpy of water at the heating start position (temperature To) in the kiln body 12, and Hgt is the dew point T ｄｅｗ This is the enthalpy of water vapor at the end of heating (temperature Tm) in the kiln body 12. In equation (8) above, Hg is the enthalpy of water vapor at the end of heating (temperature Tm) in the kiln body 12. W and a in equations (7) and (8) are the same as in equations (5) and (6).

[0043] In the above equation (2), the dew point T ｄｅｗ Then, using equations (5), (6), (7), and (8), we find Qst, Qs, Qwt, and Qw. If we take the length L1 obtained in equation (4) as the length of the first heating zone H1, then Td = T in Figure 2. ｄｅｗ This is achieved. As a result, it is possible to sufficiently suppress the condensation of water evaporated from the biomass molded body 51 and its adhesion to the biomass molded body 51. In addition, the temperature of the biomass molded body 51 inside the kiln body 12 is the dew point T. ｄｅｗ This makes it possible to suppress excessive scraping of the biomass molded body 51 in the region beyond that point, i.e., in the second heating zone H2.

[0044] Td = T ｄｅｗ It is not essential that the relationship Td ≤ T ｄｅｗ This may be the case. In this case, the first heating zone H1 heats the biomass molded body 51 to the dew point T ｄｅｗ This region heats to a lower temperature than the first heating zone, and the second heating zone H2 heats the biomass molded body 51 to a dew point T ｄｅｗ After heating until it reaches the dew point T, the biomass molded body 51 is heated to the dew point T ｄｅｗ This region becomes carbonized when heated to a higher temperature. In another example, Td ≥ T ｄｅｗ This may also be the case. In this case, the first heating zone includes a region for heating the biomass molded body 51 until it reaches the dew point, and the second heating zone H2 heats the biomass molded body 51 heated in the first heating zone H1 until it reaches the dew point T ｄｅｗ This region requires heating to a higher temperature to carbonize.

[0045] The dew point T of the kiln body 12 is determined by the moisture content in the biomass molded body 51 and the amount of biomass molded body 51 introduced. ｄｅｗThe value of Td may vary. For example, the rotary kiln 10 may be operated under conditions such that Td satisfies equation (9) or equation (10) below. In this case, the length of the first heating zone H1 will be longer or shorter than the length L1 obtained by equation (4). Even in such cases, it is possible to suppress the adhesion of condensation water to the biomass molded body 51 in the first heating zone H1 and suppress the reduction in strength of the biomass molded body 51. In the second heating zone H2, excessive scraping is suppressed and pulverization caused by the falling of the scraped-up biomass molded body 51 is suppressed.

[0046] T ｄｅｗ -50°C ≤ Td ≤ T ｄｅｗ +100℃ (9) T ｄｅｗ -40°C ≤ Td ≤ T ｄｅｗ +50℃ (10)

[0047] When the length of the first heating zone H1 is A and the length of the second heating zone H2 is B, the ratio of the length A of the first heating zone H1 to the total length of the first heating zone H1 and the second heating zone H2 (A + B) (A / (A + B)) may be 0.1 to 0.6, 0.2 to 0.5, or 0.3 to 0.5. Within this range, it becomes easier to satisfy the relationship in equation (9) or equation (10) above. Therefore, it is possible to sufficiently suppress the collapse during the production of the biomass solid fuel 53 and obtain a biomass solid fuel 53 with even higher strength.

[0048] Dew point T ｄｅｗ The ratio of the length A of the first heating zone H1 to the length L1 to reach the heating zone (A / L1) may be 0.3 to 1.5, 0.5 to 1.3, or 0.7 to 1.1. Within this range, the relationship of equation (9) or equation (10) above is more easily satisfied. Therefore, the collapse during the production of the biomass solid fuel 53 can be sufficiently suppressed, and a biomass solid fuel 53 with even higher strength can be obtained.

[0049] The first heating zone H1 heats the biomass molded body 51 to a dew point T ｄｅｗ It may include a region that is heated until it reaches T ≥ T in Figure 2. ｄｅｗThis may be the case. This will sufficiently suppress the adhesion of condensation water to the biomass molded body 51 and further suppress the decrease in strength of the biomass molded body 51. However, Td < T ｄｅｗ Even so, the collapse of the biomass molded body 51 can be sufficiently suppressed.

[0050] As shown in Figure 3, in the first heating zone H1, a plurality of first lifter blades 21 are connected to the inner circumferential surface 13 of the kiln body 12. The plurality of first lifter blades 21 include non-bent blades 23 and bent blades 20. The non-bent blades 23 have no bent portion and have a flat plate shape. As shown in Figures 3 and 4, the bent blade 20 has a base portion BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and an inclined portion IS that is closer to the rotation center C than the base portion BA and inclined toward the rotation direction r.

[0051] The curved blade 20 having this shape can increase the amount of biomass molded body 51 scraped up and increase the scraping height in the first heating zone H1. In this way, the multiple first lifter blades 21 are composed of multiple types of lifter blades, each with different scraping amounts and scraping heights for the biomass molded body 51, arranged periodically along the circumference. This reduces temperature unevenness in the biomass molded body 51 and improves temperature uniformity. Furthermore, by scraping up the biomass molded body 51, not only the biomass molded body 51 but also the gas inside the kiln body 12 is thoroughly agitated. This suppresses condensation of moisture in the gas and prevents the condensed water from adhering to the biomass molded body 51. Therefore, the strength of the biomass molded body 51 can be maintained and its collapse can be suppressed.

[0052] The angle θ between the base BA and the inclined portion IS adjacent to the base BA in the bent blade 20. １ The angle θ may be 20° or more and less than 180°, from the viewpoint of maintaining the amount and height of the biomass molded body 51 scraped up within an appropriate range. １The upper limit may be 170°, 150°, 130°, 110°, 100°, 90°, 80°, or 70°, from the viewpoint of ensuring a sufficiently large amount of material is scraped up and a sufficiently high scraping height. １ The lower limit may be 30° or 40° from a similar viewpoint. In each of the following embodiments and modifications, θ １ The angles shown may be within the numerical range mentioned above unless otherwise specified.

[0053] The ratio (Lt / Lb) of the length Lt of the inclined section IS to the length Lb of the base section BA along the radial direction of the kiln body 12 may be 0.10 to 2.0, from the viewpoint of maintaining the amount and height of the biomass molded body 51 scraped up within an appropriate range. The upper limit of the ratio (Lt / Lb) may be 1.80 or 1.60, from the viewpoint of suppressing excessive scraping. The lower limit of the ratio (Lt / Lb) may be 0.15 or 0.20, from the viewpoint of ensuring a sufficiently large amount of scraped material and a sufficiently high scraping height.

[0054] The shape of the bent blade 20 is not limited to the shape shown. For example, the bent blade 20 in Figures 3 and 4 has only one inflection point, but it may have two or more inflection points. Also, although the inclined portion IS is straight in Figures 3 and 4, it may be curved as shown in the modified example in Figure 5. In the rotary kiln 10A shown in Figure 5, the inclined portion IS of the bent blade 20A is bent in a hook shape toward the rotational direction r from the base BA. When the inclined portion IS is bent in a hook shape, the angle θ １ As shown in Figure 6, this is the angle formed between the base BA and the imaginary straight line VL1 connecting the boundary between the base BA and the inclined portion IS and the tip of the inclined portion IS in the radial cross-section of the kiln body 12.

[0055] As shown in Figures 3, 4, and 6, the angle θ in these examples １ The angle θ can be obtuse. １ This angle θ may be greater than 90° and less than 180°. １ The upper limit of this angle θ may be 170°, 160°, or 150°. １ The lower limit may be 100°, 110°, or 120°.

[0056] Figures 7 to 13 show another modified example. In the rotary kiln 10B shown in Figure 7, the kiln body 12 is equipped with a first lifter blade 21 in the first heating zone H1, including a bent blade 20B and a non-bent blade 23. The bent blade 20B has a base BA and an inclined portion IS provided closer to the rotation center C than the base BA. The inclined portion IS has a first portion ISa adjacent to the base BA and a second portion ISb provided closer to the rotation center C than the first portion ISa. The first portion ISa is inclined in the rotation direction r than the base BA, and the second portion ISb is inclined in the counter-rotation direction than the base BA.

[0057] As shown in Figure 7, when the biomass molded body 51, which has been scooped up by the bent blade 20B, falls from the bent blade 20B (first bent blade), it first collides with the second portion ISb of another bent blade 20B (second bent blade) which is located behind the first bent blade in the rotational direction, before falling to the bottom of the kiln body 12. Therefore, the impact of the fall can be reduced compared to when the biomass molded body 51 falls directly to the bottom of the kiln body 12. This further suppresses the collapse of the biomass molded body. Angle θ between the base BA and the first portion ISa in Figure 7. １ The angle θ may be obtuse and may be greater than 90° and less than 180°. １ The upper limit of this angle θ may be 170°, 160°, or 150°. １ The lower limit may be 100°, 110°, or 120°.

[0058] In the rotary kiln 10C shown in Figure 8, the kiln body 12 is equipped with a plurality of first lifter blades 21, including a bent blade 20C and a non-bent blade 23, in the first heating zone H1. The bent blade 20C has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and an inclined portion IS that is closer to the rotation center C than the base BA and inclined toward the rotation direction r. In this specification, "closer to the rotation center C" is determined based on the portion located closest to the inner circumferential surface 13. One end of the base BA is in contact with the inner circumferential surface 13, while the inclined portion IS is away from the inner circumferential surface 13, and therefore is located closer to the rotation center C than the base BA.

[0059] θ in Figure 8 １ This is θ in Figure 3. １ It is smaller than θ. １ By setting the angle to 90° or less, the scraping height of the biomass molded body 51 can be sufficiently increased, and the time that the bent blade 20C holds the biomass molded body 51 can be extended.

[0060] θ １ If the angle is less than 90°, the ratio (Lt / Lb) of the length of the inclined section IS to the length Lb of the base section BA, measured in the same manner as in Figure 4, may be 0.1 to 1.0, from the viewpoint of increasing the height to which the biomass molded body 51 is shoved up and evenly distributing the biomass molded body 51 throughout the entire kiln body 12. The upper limit of the ratio (Lt / Lb) may be 0.8 or 0.6, from the viewpoint of evenly distributing the biomass molded body 51 throughout the entire kiln. The lower limit of the ratio (Lt / Lb) may be 0.2 or 0.3, from the viewpoint of ensuring a sufficient amount of biomass molded body 51 is shoved up.

[0061] In the rotary kiln 10D shown in Figure 9, the kiln body 12 is equipped with a plurality of first lifter blades 21, including a bent blade 20D and a non-bent blade 23, in the first heating zone H1. The bent blade 20D has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and an inclined portion IS provided closer to the rotation center C than the base BA. The inclined portion IS has a first portion ISa adjacent to the base BA and inclined in the rotation direction r closer to the rotation center C than the base BA, and a second portion ISb adjacent to the first portion ISa and inclined toward the base BA. The angle between the base BA and the first portion ISa is θ １ This may be the case. The bent blade 20D can sufficiently raise the scraping height of the biomass molded body 51 and sufficiently extend the holding time of the biomass molded body 51. In this example, the second part ISb is inclined in the counter-rotational direction with respect to a virtual line extending the first part ISa toward the inner circumferential surface 13, but in another example it may be inclined in the rotational direction r or parallel to the radial direction of the kiln body 12.

[0062] In the rotary kiln 10E shown in Figure 10, the kiln body 12 is equipped with a plurality of first lifter blades 21, including a bent blade 20E and a non-bent blade 23, in the first heating zone H1. The bent blade 20E has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and an inclined portion IS adjacent to the base BA, which is inclined toward the rotation direction r closer to the rotation center C than the base BA. The inclined portion IS is curved in a hook shape. As shown in Figure 10, the bent blade 20E can sufficiently raise the scraping height of the biomass molded body 51 and sufficiently extend the holding time of the biomass molded body 51.

[0063] In the rotary kiln 10F shown in Figure 11, the kiln body 12 is equipped with a plurality of first lifter blades 21, including a bent blade 20F and a non-bent blade 23, in the first heating zone H1. The bent blade 20F has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and an inclined portion IS adjacent to the base BA and inclined toward the rotation direction r, closer to the rotation center C than the base BA. The inclined portion IS is perpendicular to the base BA. As shown in Figure 11, the bent blade 20F can sufficiently raise the scraping height of the biomass molded body 51 and sufficiently extend the holding time of the biomass molded body 51.

[0064] In the examples shown in Figures 8 to 11, the biomass molded body 51 can be spread with sufficiently high uniformity across the entire first heating zone H1 of the kiln body 12. This further improves the dispersibility of water vapor generated from the biomass molded body 51. In addition, the increased height of the scooping up of the biomass molded body 51 ensures that the gas inside the kiln body 12 is thoroughly agitated. This further suppresses condensation of moisture in the gas and adhesion of condensed water to the biomass molded body 51. Therefore, the strength of the biomass molded body 51 can be maintained at an even higher level, and the collapse of the biomass molded body 51 can be further suppressed.

[0065] Angle θ in Figures 8, 9, and 11 １ This is the angle θ in Figure 3. １ It is smaller than the angle θ in Figures 8 and 9. １ The angle is acute, as shown in the angle θ in Figure 11. １ The angles are almost right angles. Angles θ in Figures 8 and 9 １ The angle θ in Figures 8 and 9 may be between 20° and 90°, or 20° or more and less than 90°. １ The upper limit may be 80° or 70°. Angle θ １ The lower limit may be 30° or 40°. The angle θ in Figure 10 is measured in the same manner as in Figure 6. １ This is the angle θ in Figure 6. １ It is smaller than the angle θ. １ By reducing the size of the biomass molded body 51, the holding time of the biomass molded body 51 can be extended.

[0066] In the rotary kiln 10G shown in Figure 12, the kiln body 12 is equipped with a plurality of first lifter blades 21, including a bent blade 20G and a non-bent blade 23, in the first heating zone H1. The bent blade 20G has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and a projection 25 at the tip of the base BA that is directed toward the rotation direction r. The bent blade 20G with the projection 25 can scrape up a larger amount of biomass molded body 51 per unit length of the kiln body 12 compared to a lifter blade of the same length that does not have the projection 25. The projection 25 of the bent blade 20G is hollow inside. This cavity may be used as a flow path CA through which hot gas flows. This allows the heating of the biomass molded body 51 to proceed even more rapidly.

[0067] In the rotary kiln 10H shown in Figure 13, the kiln body 12 is equipped with a plurality of first lifter blades 21, including a bent blade 20H and a non-bent blade 23, in the first heating zone H1. The bent blade 20H has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, a projection 25 at the tip of the base BA toward the rotation direction r, and an inclined portion IS that inclins in the counter-rotation direction from the tip of the base BA. The inside of the projection 25 of the bent blade 20H is hollow. This cavity may be used as a flow path CA through which hot gas flows. This allows the heating of the biomass molded body 51 to proceed even more rapidly.

[0068] The hot gas flowing through the channel CA in Figures 12 and 13 may be the same as, or different from, the hot gas introduced from the gas inlet 43 in Figure 1. The hot gas that has flowed through channel CA may be discharged to the outside of the kiln body 12, for example, near the boundary between the first heating zone H1 and the second heating zone H2. The hot gas that has flowed through channel CA may also be discharged into the kiln body 12. However, if it is discharged into the kiln body 12, the concentration of flammable components in the gas inside the kiln body 12 will be reduced. For this reason, when the gas inside the kiln body 12 is burned in the combustion furnace 40, it is preferable to discharge the hot gas that has flowed through channel CA to the outside of the rotary kilns 10G and 10H.

[0069] In this embodiment, the multiple first lifter blades 21 are configured with multiple types of lifter blades, each with a different amount of biomass molded body 51 being scraped up, arranged periodically along the circumference. The multiple types of lifter blades include bent blades 20 or bent blades 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H (hereinafter collectively referred to as "20A to 20H") and non-bent blades 23. By including non-bent blades 23 in the multiple first lifter blades 21 in the first heating zone H1, it is possible to suppress excessive scraping of the biomass molded body 51. The ratio of the number of bent blades 20 (20A to 20H) to the total number of multiple first lifter blades 21 may be 0.1 to 0.8, 0.2 to 0.6, or 0.33 to 0.5.

[0070] For example, if all of the multiple first lifter blades 21 are bent blades 20 (or bent blades 20A to 20H), the amount of biomass molded body 51 raked up increases, reducing the amount of biomass molded body 51 remaining at the bottom of the kiln body 12, making it easier for the inner surface 13 of the kiln body 12 to be exposed. In this case, the biomass molded body 51 raked up by the bent blades 20 (20A to 20H) is more likely to directly collide with the inner surface 13 of the kiln body 12 when it falls. This impact may cause the biomass molded body 51 to collapse. In contrast, if some of the multiple first lifter blades 21 are non-bent blades 23, the amount of biomass molded body 51 remaining at the bottom of the kiln body 12 can be maintained. This reduces the frequency of the biomass molded body 51 directly colliding with the inner surface 13. The biomass molded body 51 that remains at the bottom of the kiln body 12 is moderately stirred by the non-bent blade 23, thereby suppressing the occurrence of temperature unevenness. From this viewpoint, the non-bent blade 23 may be shorter in length along the radial direction of the kiln body 12 than the bent blade 20 (or bent blades 20A to 20H). Length L of the bent blade 20 (20A to 20H) along the radial direction of the kiln body 12 ２０ (In Figure 4, L ２０ =Lb+Lt×cos(180°−θ １ ) The length L of the non-bending blade 23 relative to )２３ Ratio (L ２３ / L ２０ ) may be, for example, less than 1.0, 0.1 to 0.9, 0.2 to 0.8, or 0.3 to 0.6.

[0071] Returning to Figure 1, the biomass molded body 51, heated in the first heating zone H1 equipped with multiple first lifter blades 21, is subsequently heated in the second heating zone H2 of the kiln body 12. The second heating zone H2 is located downstream of the first heating zone H1. In the second heating zone H2, as shown in Figure 2, the biomass molded body 51 is heated to a temperature higher than temperature Td. The maximum temperature Tm that the biomass molded body 51 (biomass solid fuel 53) reaches in the second heating zone H2 may be, for example, 200 to 350°C or 200 to 300°C. By heating at such a temperature, the carbonization of the biomass molded body 51 proceeds sufficiently, and a biomass solid fuel 53 with sufficiently high strength is obtained. Since the temperature of the biomass molded body 51 in the second heating zone H2 of the kiln body 12 is higher than the temperature of the biomass molded body 51 in the first heating zone H1, moisture in the atmosphere is less likely to condense. Therefore, moisture is less likely to condense in the second heating zone H2 than in the first heating zone H1. Consequently, the blade pattern of the second heating zone H2 is different from that of the first heating zone H1.

[0072] Figure 14 is a radial cross-sectional view showing an example of the second heating zone H2 of the kiln body 12 in a rotary kiln 10 (10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H). In the example in Figure 14, all of the multiple second lifter blades 22 in the second heating zone H2 are composed of non-bent blades 24. The length L of the non-bent blade 24 along the radial direction of the kiln body 12. ２４ The length L of the non-bending blade 23 in the first heating zone H1 is... ２３It may be the same as above. In this case, the non-bending blade 23 and the non-bending blade 24 may be connected along the rotation center C of the kiln body 12. However, the plurality of second lifter blades 22 are not limited to being composed only of non-bending blades 24, and some of the plurality of second lifter blades 22 may be bending blades similar to the bending blade 20 shown in Figure 3. However, the ratio of the number of bending blades to the total number of the plurality of second lifter blades 22 may be smaller than the ratio of the total number of bending blades 20 (20A to 20H) to the total number of the plurality of first lifter blades 21. The ratio of the number of bending blades 20 to the number of the plurality of second lifter blades 22 may be 0.2 or less, 0.1 or less, or 0.

[0073] In the second heating zone H2, for example, by reducing the proportion of curved blades compared to the first heating zone H1, the amount of biomass molded body 51 scraped up per unit length of the kiln body 12 can be reduced, and the scraping height can be lowered. This effectively suppresses the collapse of the biomass molded body 51 in the second heating zone H2. The length of the non-curved blade 24 in the second heating zone H2 may be the same as or different from the non-curved blade 23 in the first heating zone H1.

[0074] The multiple second lifter blades 22 in the second heating zone H2 may have different lengths from each other, similar to the multiple first lifter blades 21 in Figure 15. That is, some of the second lifter blades 22 may be short blades and others may be long blades. However, the average value LS of the lengths of the multiple second lifter blades 22 along the radial direction of the kiln body 12 may be smaller than the average value LF of the lengths of the multiple first lifter blades 21 along the same radial direction (LF > LS). This makes it possible to sufficiently reduce the amount of condensation water adhering to the biomass molded body 51 in the first heating zone H1. LF / LS may be 1.1 to 2.0, 1.2 to 1.8, or 1.3 to 1.6. Even when the multiple first lifter blades 21 have bent blades, the relationship and ratio of LF and LS may satisfy the above-mentioned relationship. The average value LF is the arithmetic mean of the lengths of each of the multiple first lifter blades 21. The average value LS is the arithmetic mean of the lengths of each of the multiple second lifter blades 22.

[0075] The shapes and relative sizes of the multiple first lifter blades 21 and the multiple second lifter blades 22 are not limited to the examples described above. In another modification, as shown in Figure 15, the inner circumferential surface 13 of the kiln body 12 of the rotary kiln 10I is provided with multiple first lifter blades 21 having different lengths along the direction from the inner circumferential surface 13 toward the rotation center C. The multiple first lifter blades 21 in Figure 15 include non-bent blades 23 (short blades) similar to those in Figure 3 and non-bent blades 28 (long blades) that are longer than the non-bent blades 23. The non-bent blades 28 may have a flat plate shape similar to the non-bent blades 23. Thus, the multiple first lifter blades 21 do not necessarily include bent blades.

[0076] Since the multiple first lifter blades 21 in Figure 15 have long blades, the amount of biomass molded body 51 shoveled up per unit length of the kiln body 12 can be increased compared to the case where all of the first lifter blades 21 have short blades. This reduces temperature unevenness in the biomass molded body 51 and improves temperature uniformity. In addition, by increasing the amount of biomass molded body 51 shoveled up per unit length of the kiln body 12, the gas inside the kiln body 12 is also sufficiently agitated. This suppresses condensation of moisture in the gas in the first heating zone H1 and the adhesion of condensed water to the biomass molded body 51. This suppresses a decrease in the strength of the biomass molded body 51 and prevents it from collapsing.

[0077] The ratio of the length of the non-bending blade 28 (long blade) to the non-bending blade 23 (short blade) may be 1.5 to 4.0, 1.8 to 3.5, or 2.0 to 3.0. The ratio of the number of non-bending blades 28 (long blades) to the number of first lifter blades 21 may be 0.1 to 0.8, 0.2 to 0.6, or 0.3 to 0.5.

[0078] The biomass solid fuel 53 produced in the second heating zone H2 is moved to the discharge section 30 via the second unheated zone Z2. The second unheated zone Z2 may be provided with multiple lifter blades, similar to the second heating zone H2, or it may be provided with spiral blades, similar to the first unheated zone Z1. The biomass solid fuel 53 produced in the rotary kiln 10 is discharged to the outside through the outlet valve 32 in the discharge section 30. In this way, collapse during the production of the biomass solid fuel 53 is suppressed, and biomass solid fuel 53 with high strength can be produced with a high yield. In Figure 2, the temperature of the biomass molded body is maintained at temperature Tm in the second unheated zone Z2, but the temperature of the biomass molded body may be lower than temperature Tm.

[0079] <Second Embodiment> The biomass solid fuel production apparatus according to the second embodiment is similar to the biomass solid fuel production apparatus according to the first embodiment, and the kiln body comprises a first heating zone having a plurality of first lifter blades for heating biomass molded bodies, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded bodies heated in the first heating zone. The plurality of first lifter blades and the plurality of second lifter blades are configured such that the amount of biomass molded bodies scraped up per unit length of the kiln body is greater in the first heating zone than in the second heating zone.

[0080] The plurality of first lifter blades according to the second embodiment include a plurality of bent blades, each having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, a first portion adjacent to the base portion and inclined in the direction of rotation, and a second portion provided closer to the center of rotation than the first portion and inclined in the direction of counter-rotation. That is, the plurality of bent blades have the base portion, the first portion, and the second portion in this order from the inner circumferential surface of the kiln body toward the center of rotation. The structure of the rotary kiln other than the plurality of first lifter blades may be the same as in the first embodiment.

[0081] Figures 16 and 17 are radial cross-sectional views of the first heating zone H1 of the kiln body 12, showing an example of a second embodiment. The kiln body 12 of the rotary kiln 10J shown in Figure 16 has a plurality of first lifter blades 21. The plurality of first lifter blades 21 include non-bent blades 23 and bent blades 20J. The bent blade 20J includes a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, a first portion IS1 adjacent to the base BA and inclined in the rotational direction, and an inclined portion IS including a second portion IS2 provided closer to the rotation center C than the first portion IS1 and inclined in the counter-rotational direction.

[0082] The angle θ between the base BA and the first part IS1 of the inclined part IS. １ This angle θ may be obtuse. １ This angle θ may be greater than 90° and less than 180°. １ The upper limit of this angle θ may be 170°, 160°, or 150°. １The lower limit may be 100°, 110°, or 120°. The angle θ between the first part IS1 and the second part IS2. ２ This angle θ can be between 10° and 80°. ２ The lower limit may be 10°, 20°, or 30°. This angle θ ２ The upper limit may be 70°, 60°, 50°, or 40°.

[0083] The bent blade 20J may drop the scooped-up biomass molded body 51 onto a bent blade 20J that is located in front of the bent blade 20J that holds the biomass molded body 51 when viewed in the rotational direction r of the kiln body 12. For example, if one of the bent blades 20J in Figure 16 is the first bent blade 1B, then in Figure 16, the biomass molded body 51 is held in the first holding part α of the first bent blade. When the kiln body 12 rotates by, for example, 50 to 60° in the rotational direction r from the state in Figure 16, the biomass molded body 51 that was held in the first holding part α falls downward. At least a portion of the biomass molded body 51 that fell from the first holding part α falls into the second holding part β of the second bent blade 2B, which is located in front of the first bent blade 1B in the rotational direction r when viewed in the rotational direction r. This reduces the impact of the fall compared to when the entire biomass molded body 51 falls directly from the first holding section α to the bottom of the kiln body 12. Therefore, the collapse of the biomass molded body 51 can be suppressed. In this case, the biomass molded body 51 moves from the first holding section α to the second holding section β, and the gas in the first heating zone H1 is agitated. Therefore, the impact of the fall is mitigated, and the reduction in the strength of the biomass molded body 51 due to the adhesion of condensation water can be suppressed. In this way, the pulverization of the biomass molded body can be sufficiently suppressed.

[0084] The first holding part α is formed by the base part BA and the first part IS1 of the inclined part IS. The second holding part β is formed by the base part BA and the first part IS1 and the second part IS2 of the inclined part IS. When the side of the bent blade 20J facing the rotation direction r is considered the front surface and the side facing the opposite rotation direction is considered the back surface, the first holding part α is formed on the front surface side of the bent blade 20J. The second holding part β is formed on the back surface side of the bent blade 20J. The biomass molded body 51 held by the second holding part β may move to the bottom of the kiln body 12 while being held by the second holding part β.

[0085] At least a portion of the biomass molded body 51 held in the first holding section α may fall into the holding section of another bending blade 20J located in front of the second bending blade 2B in the rotational direction, instead of falling into the second holding section β. At least a portion of the biomass molded body 51 held in the first holding section α may fall onto the second bending blade 2B, or onto the front surface of the second portion IS2 of the inclined section IS of another bending blade 20J located in front of it in the rotational direction. This reduces the impact of the fall compared to when the biomass molded body 51 falls directly onto the bottom of the kiln body 12 while stirring the gas in the first heating zone H1.

[0086] The rotary kiln 10K shown in Figure 17 has multiple first lifter blades 21 in the kiln body 12, which consist only of bent blades 20K. The bent blade 20K includes a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, a first portion IS1 adjacent to the base BA and inclined in the rotational direction, and an inclined portion IS including a second portion IS2 provided closer to the rotation center C than the first portion IS1 and inclined in the counter-rotational direction. The angle θ in the bent blade 20J in Figure 16 １ The angle was obtuse, but the angle θ in the bent blade 20K in Figure 17 １ The angle is acute. However, the angle θ １ The angle can also be a right angle. Specifically, this angle θ １ This angle θ may be between 20° and 90°, or 20° or more and less than 90°. １ The upper limit may be 80° or 70°. This angle θ １The lower limit may be 30° or 40°. Such a bent blade 20K can also reduce the impact of the fall of the biomass molded body 51, similar to the bent blade 20J in FIG. 16. The angle θ formed between the first portion IS1 and the second portion IS2 of the bent blade 20K ２ may be the same as that of the bent blade 20J. The plurality of first lifter blades 21 in FIG. 17 do not include non-bent blades, but may include non-bent blades 23, similar to FIG. 16.

[0087] <Third Embodiment> Similar to the biomass solid fuel production apparatus according to the first embodiment, the biomass solid fuel production apparatus according to the third embodiment has a kiln body having a plurality of first lifter blades, a first heating zone for heating the biomass molded body, and a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone. The plurality of first lifter blades and the plurality of second lifter blades in the third embodiment may or may not be configured such that the amount of biomass molded body scraped up per unit length of the kiln body is greater in the first heating zone than in the second heating zone.

[0088] The plurality of first lifter blades according to the third embodiment include a plurality of bent blades having a base portion extending from the inner peripheral surface of the kiln body toward the rotation center and an inclined portion including a portion inclined in the reverse rotation direction closer to the rotation center than the base portion. The structure of the rotary kiln other than the plurality of first lifter blades may be the same as that of the first and second embodiments.

[0089] FIGS. 18 and 19 are radial cross-sectional views of the first heating zone H1 of the kiln body 12 showing an example of the third embodiment. A plurality of first lifter blades 21 are connected to the inner peripheral surface 13 of the kiln body 12 of the rotary kiln 10L shown in FIG. 18. The plurality of first lifter blades 21 include non-bent blades 23 and bent blades 20L. The bent blade 20L has a base portion BA extending from the inner peripheral surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12 and an inclined portion IS inclined in the reverse rotation direction closer to the rotation center C than the base portion BA.

[0090] The biomass molded body 51 scraped up by the bending blade 20L at the bottom of the kiln body 12 falls from the bending blade 20L when the kiln body 12 rotates in the rotation direction r. At this time, the biomass molded body 51 falls while sliding on the inclined portion IS of the bending blade 20L. Thereby, the impact when the biomass molded body 51 falls to the bottom of the kiln body 12 can be reduced as compared with the case where the inclined portion IS is not inclined. Thereby, the collapse of the biomass molded body 51 can be suppressed.

[0091] Since the length of the base BA of the bending blade 20L is longer than that of the non-bending blade 23, more biomass molded bodies 51 can be scraped up than the non-bending blade 23. By increasing the length of the base of the bending blade 20L in the plurality of first lifter blades 21, the amount of biomass molded bodies scraped up per unit length of the kiln body can be increased in the first heating zone H1 compared to the second heating zone H2. The length L of the bending blade 20L along the radial direction of the kiln body 12 ２０ (In FIG. 4, L ２０ = Lb + Lt × cos(180° - θ １ ).) The ratio (L ２３ / L ２３ / L ２０ ) may be 0.1 to 0.9, 0.2 to 0.8, or 0.3 to 0.6.

[0092] The angle θ formed by the base BA and the inclined portion IS adjacent to the base BA in the bending blade 20 ３ may be 100° to 170° from the viewpoint of sufficiently reducing the impact of the fall of the biomass molded body 51. The upper limit of the angle θ ３ may be 160° or 150°. The lower limit of the angle θ ３ may be 110° or 120°.

[0093] The rotary kiln 10M shown in Figure 19 has multiple first lifter blades 21, including non-bent blades 23 and bent blades 20M. The bent blade 20M has a base BA extending from the inner circumferential surface 13 of the kiln body 12 toward the rotation center C of the kiln body 12, and an inclined portion IS that is closer to the rotation center C than the base BA and inclined in the counter-rotation direction. The inclined portion IS is curved in an arc shape. Even with such an inclined portion IS, the impact when the biomass molded body 51 falls to the bottom of the kiln body 12 can be reduced. This can suppress the collapse of the biomass molded body 51. The angle θ when the inclined portion IS is curved in this way ３ Similar to Figure 6, the angle θ can be measured as the angle formed between the base BA and the base BA in the radial cross-section of the kiln body 12, by a virtual straight line VL2 connecting the boundary between the base BA and the inclined portion IS and the tip of the inclined portion IS. ３ The range may be as explained in the example in Figure 18.

[0094] The shape of the curved blades 20L and 20M is not limited to the shape shown. For example, the curved blade 20L in Figure 18 has one curved section, but it may have two or more curved sections. The curved blade 20M in Figure 19 has one inflection point, but it may have two or more inflection points. The ratio of the number of curved blades 20L and 20M to the total number of first lifter blades 21 may be 0.1 to 0.8, 0.2 to 0.6, or 0.25 to 0.5. The ratio of the length of the non-curved blade 23 to the length of the curved blades 20L and 20M along the radial direction of the kiln body 12 may be 0.1 to 0.9, 0.2 to 0.8, or 0.3 to 0.6.

[0095] <Fourth Embodiment> The biomass solid fuel production apparatus according to the fourth embodiment, like the biomass solid fuel production apparatus according to each embodiment described above, comprises a kiln body having a plurality of first lifter blades and a first heating zone for heating a biomass molded body, and a plurality of second lifter blades and a second heating zone for further heating the biomass molded body heated in the first heating zone. The plurality of first lifter blades and the plurality of second lifter blades satisfy one or both of the following (a) and (b): (a) When the average value of the lengths of the plurality of first lifter blades along the radial direction of the kiln body is LF, and the average value of the lengths of the plurality of second lifter blades along the radial direction is LS, then LF > LS. (b) The number of the plurality of first lifter blades is greater than the number of the plurality of second lifter blades.

[0096] By satisfying either or both of the above conditions (a) and (b), the amount of biomass molded material scraped up per unit length of the kiln body can be increased in the first heating zone compared to the second heating zone. This ensures that the biomass molded material and gas are thoroughly mixed, and the biomass molded material is heated with high uniformity. In addition, this also suppresses the adhesion of condensation water to the biomass molded material in the first heating zone. In the second heating zone, excessive scraping is suppressed, and pulverization caused by the falling of the scraped biomass molded material is suppressed. The above manufacturing apparatus can suppress collapse during the production of biomass solid fuel due to these factors.

[0097] Figures 20 and 21 are radial cross-sectional views of the first heating zone H1 and the second heating zone H2 of the kiln body 12, showing an example of the fourth embodiment. Multiple first lifter blades 21 are connected to the inner circumferential surface 13 of the first heating zone H1 of the kiln body 12 of the rotary kiln 10N shown in Figure 20. The multiple first lifter blades 21 consist only of non-bent blades 26 having a flat plate shape. The lengths of the multiple first lifter blades 21 along the radial direction of the kiln body 12 may be the same or may differ from one another.

[0098] In the rotary kiln 10N shown in Figure 21, multiple second lifter blades 22 are connected to the inner circumferential surface 13 of the second heating zone H2 of the kiln body 12. The multiple second lifter blades 22 consist only of non-bent blades 27 having a flat plate shape. The lengths of the multiple second lifter blades 22 along the radial direction of the kiln body 12 may be the same or may differ from one another.

[0099] The number of first lifter blades 21 shown in Figure 20 is greater than the number of second lifter blades 22 shown in Figure 21. Specifically, the number of first lifter blades 21 is twice the number of second lifter blades 22. When the lengths of the multiple first lifter blades 21 and the multiple second lifter blades 22 along the radial direction of the kiln body 12 are approximately the same, the amount of biomass molded body 51 scraped up per unit length of the kiln body 12 can be greater in the first heating zone H1 than in the second heating zone H2. From the viewpoint of sufficiently increasing the amount of biomass molded body 51 scraped up in the first heating zone H1, the ratio of the number of first lifter blades 21 to the number of second lifter blades 22 may be 1.1 or more, 1.3 or more, 1.5 or more, or 2.0 or more. The ratio of the number of first lifter blades 21 to the number of second lifter blades 22 may be 5.0 or less, 4.0 or less, or 3.0 or less.

[0100] In a modified example, the average value LF of the lengths of the multiple first lifter blades 21 along the radial direction of the kiln body 12 may be greater than the average value LS of the lengths of the multiple second lifter blades 22 along the radial direction of the kiln body 12 (LF > LS). From the viewpoint of sufficiently increasing the amount of biomass molded body 51 scraped up in the first heating zone H1, LF / LS may be 1.2 or more, 1.5 or more, or 2.0 or more. From the viewpoint of maintaining agitation in the second heating zone H2, LF / LS may be 5.0 or less, 4.0 or less, or 3.0 or less. In another modified example, at least a portion of the multiple first lifter blades 21 may be bent blades. The bent blades may be, for example, any of the bent blades in the first embodiment, the second embodiment, and the third embodiment described above.

[0101] In another modification, the number of first lifter blades 21 and the number of second lifter blades 22 may be the same, and LF may be greater than LS. The numerical range of LF / LS may be as described above.

[0102] In this embodiment or in each of its modified versions, the biomass solid fuel production apparatus is made more efficient at stirring up the biomass molded body 51 in the first heating zone H1. This ensures that the biomass molded body 51 and the gas are thoroughly mixed. As a result, the biomass molded body 51 is heated with high uniformity, and the adhesion of condensation water to the biomass molded body 51 is suppressed. Furthermore, in the second heating zone H2, excessive stirring is suppressed, and pulverization caused by the falling of the stirred-up biomass molded body 51 is suppressed. Through these factors, the above production apparatus can suppress the collapse of the biomass solid fuel 53 during production.

[0103] <Examples of arrangement of multiple first lifter blades 21 and multiple second lifter blades 22> Each of the multiple first lifter blades 21 in the above embodiments may be arranged as a single plate-shaped member parallel to the rotation center C of the kiln body 12, as shown in Figure 22(A). Figure 22(A) shows the bent blade 20L and the non-bent blade 23 provided in the first heating zone H1 of the biomass solid fuel production apparatus of the third embodiment. The multiple second lifter blades 22 in the second heating zone H2 may also be arranged as a single plate, similar to the multiple first lifter blades 21. However, the arrangement of the multiple first lifter blades 21 and the multiple second lifter blades 22 is not limited to these.

[0104] In Figure 22(B) or Figure 22(C), when a virtual line parallel to the rotation center C of the kiln body 12 is defined as the reference line PL, the multiple segmented blades 23a constituting the non-bent blade 23 are connected to the inner circumferential surface 13 so as to be inclined at a predetermined angle with respect to the reference line PL. The bent blades (long blades, short blades) of each embodiment are also composed of multiple segmented blades, and the multiple segmented blades may be connected to the inner circumferential surface 13 so as to be inclined at a predetermined angle with respect to the reference line PL. When the biomass molded body 51 flows through the kiln body in the direction of arrow D, the flow of the biomass molded body 51 in the direction of arrow D can be made even smoother by arranging the segmented blades 23a at an angle as shown in Figure 22(B). On the other hand, by arranging the segmented blades 23a at an angle as shown in Figure 22(C), the time that the biomass molded body 51 remains in the kiln body 12 can be increased. In Figure 22(B) or Figure 22(C), the non-bent blades are segmented, but the bent blades may also be segmented and provided. One or both of the first lifter blade 21 and the plurality of second lifter blades 22 may be provided as split blades.

[0105] <Examples of the Structure of Multiple First Lifter Blades 21 and Multiple Second Lifter Blades 22> At least a portion of the multiple first lifter blades 21 and multiple second lifter blades 22 in each of the above embodiments may be made of ordinary plate-shaped members, or plate-shaped members having through holes. For example, as shown in Figure 23(A), the multiple first lifter blades 21 and multiple second lifter blades 22 may be made of mesh-like members. For example, as shown in Figure 23(B), slits SL may be formed in at least a portion of the multiple first lifter blades 21 (bent blades 20). Similar slits SL may also be provided in at least a portion of the non-bent blades and the multiple second lifter blades 22. By using plate-shaped members having through holes in this way, the diffusion of gas containing water vapor is promoted, which promotes the drying of the biomass molded body 51 and sufficiently suppresses water condensation.

[0106] As shown in Figure 23(C), plate-shaped members SD may be attached to the ends of the kiln body 12 in the direction of the rotation axis of at least some of the multiple first lifter blades 21 (bent blades 20). The plate-shaped members SD and the inclined portion IS may form a recess. Similar plate-shaped members SD may also be attached to at least some of the non-bent blades and the multiple second lifter blades 22. This increases the heat transfer area of ​​the multiple first lifter blades 21 and the multiple second lifter blades 22, thereby promoting the drying and carbonization of the biomass molded body 51. It also increases the amount of biomass molded body 51 that can be scraped up.

[0107] [Method for Manufacturing Biomass Solid Fuel] In a method for manufacturing biomass solid fuel according to one embodiment, a biomass solid fuel manufacturing apparatus 100 equipped with any of the rotary kilns 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K, 10L, 10M, 10N, or modified versions thereof (hereinafter referred to as "rotary kilns 10, 10A to 10N") may be used. This manufacturing method includes a first heating step in which a biomass molded body 51 is introduced into the rotary kilns 10, 10A to 10N and the biomass molded body 51 is heated in a first heating zone H1, and a second heating step in which the biomass molded body 51 heated in the first heating step is further heated in a second heating zone H2. The first heating step may be carried out based on the above description regarding the first heating zone H1. The second heating step may be carried out based on the above description regarding the second heating zone H2. In the second heating step, the biomass molded body 51 is carbonized to obtain biomass solid fuel 53.

[0108] The method may include an introduction step before the first heating step in which the biomass molded body 51 is introduced into the rotary kilns 10, 10A to 10N. After the second heating step, there may be an extraction step in which the biomass molded body 51 is extracted from the rotary kilns 10, 10A to 10N. After the extraction step, there may be a step of classifying and cooling the biomass solid fuel. Each step may be carried out according to the description of the embodiment of the biomass solid fuel production apparatus. Since this production method uses the biomass solid fuel production apparatus 100, collapse during the production of biomass solid fuel can be sufficiently suppressed. In addition, biomass solid fuel with high strength can be produced with a sufficiently high yield.

[0109] The pulverization rate when producing biomass solid fuel 53 from biomass molded body 51 may be 35% by weight or less, 31% by weight or less, or 28% by weight or less. The pulverization rate can be calculated using the formula {1 - (m1 / m0)} × 100, where m1 and m0 are as described in formula (1) above.

[0110] Although several embodiments of the present disclosure have been described above, the present disclosure is not limited in any way to the above embodiments. For example, in the kiln body 12, the biomass molded body 51 and the inert gas flow in the same direction (parallel flow), but in another embodiment, the inert gas may flow in the opposite direction to the direction of movement of the biomass molded body 51 (counterflow). That is, the inert gas may be introduced into the kiln body 12 from the outlet 30 side and discharged to the outside from the inlet 50 side. Also, one or both of the first unheated zone Z1 and the second unheated zone Z2 may be omitted. The heating zone may be divided into three or more regions with different lifter blade shapes or sizes.

[0111] As described above, this disclosure includes the following embodiments: [1] A biomass solid fuel manufacturing apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, wherein the plurality of first lifter blades and the plurality of second lifter blades are configured such that the amount of biomass molded body scraped up per unit length of the kiln body is greater in the first heating zone than in the second heating zone. [2] The biomass solid fuel manufacturing apparatus according to [1], wherein the plurality of first lifter blades comprises a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion provided closer to the center of rotation than the base portion and including a portion inclined in the direction of rotation. [3] The angle θ between the base and the portion inclined in the rotational direction when viewed in the radial cross-section of the kiln body. １A biomass solid fuel manufacturing apparatus according to any one of [2] to [3], wherein the angle is 20° or more and less than 180°. [4] A biomass solid fuel manufacturing apparatus according to any one of [1] to [3], wherein the plurality of first lifter blades include a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, a first portion adjacent to the base portion and inclined in the direction of rotation, and a second portion provided closer to the center of rotation than the first portion and inclined in the counter-rotation direction. [5] A biomass solid fuel manufacturing apparatus according to any one of [2] to [4], wherein, when viewed in the direction of rotation, the plurality of bent blades, including a first bent blade and a second bent blade located forward in the direction of rotation of the first bent blade, are configured such that at least a portion of the biomass molded body scraped up by a first holding portion α formed by the base portion and the first portion of the first bent blade falls into a second holding portion β formed by the base portion, the first portion and the second portion of the second bent blade. [6] A biomass solid fuel production apparatus according to any one of [2] to [5], wherein, when viewed in the direction of rotation, the plurality of bent blades, including a first bent blade and a second bent blade positioned forward of the first bent blade in the direction of rotation, are configured such that at least a portion of the biomass molded body scraped up by a first holding portion α formed by the base and the second portion of the first bent blade falls toward the second portion of the second bent blade. [7] A biomass solid fuel manufacturing apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, and the plurality of first lifter blades comprises a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion including a portion that is inclined in the counter-rotation direction closer to the center of rotation than the base portion. [8] An angle θ between the base portion and the portion inclined in the counter-rotation direction when viewed in the radial cross-section of the kiln body. ３However, the biomass solid fuel production apparatus described in [7] is 20° to 90°. [9] The plurality of first lifter blades include the bent blades and the non-bent blades, and the average value of the length of the bent blades along the radial direction of the kiln body is L ２０ , and the average value of the length of the non-bent blade along the radial direction is L ２３ When that is the case, L ２０ > L ２３A biomass solid fuel manufacturing apparatus according to any one of [2] to [8].

[10] A biomass solid fuel manufacturing apparatus according to any one of [1] to [9], wherein LF is the average value of the lengths of the plurality of first lifter blades along the radial direction of the kiln body, and LS is the average value of the lengths of the plurality of second lifter blades along the radial direction, and LF > LS.

[11] A biomass solid fuel manufacturing apparatus according to any one of [1] to

[10] , wherein the number of the plurality of first lifter blades is greater than the number of the plurality of second lifter blades.

[12] A biomass solid fuel manufacturing apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, and satisfies one or both of the following (a) and (b). (a) When LF is the average value of the lengths of the plurality of first lifter blades along the radial direction of the kiln body, and LS is the average value of the lengths of the plurality of second lifter blades along the radial direction, LF > LS. (b) The number of the plurality of first lifter blades is greater than the number of the plurality of second lifter blades.

[13] The biomass solid fuel production apparatus according to claim 12, wherein the plurality of first lifter blades include a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion including a portion that is inclined in the rotational direction closer to the center of rotation than the base portion.

[14] The biomass solid fuel production apparatus according to any one of [1] to

[13] , wherein the plurality of first lifter blades are configured such that a plurality of lifter blades of different types, each with a different amount of the biomass molded body being scraped up, are arranged periodically along the circumferential direction.

[15] The rotary kiln is an externally heated rotary kiln having an outer cylinder outside the kiln body, and the first heating zone and the second heating zone heat the biomass molded body introduced into the kiln body by a heating fluid flowing between the kiln body and the outer cylinder, the biomass solid fuel production apparatus according to any one of [1] to

[14] .

[16] A biomass solid fuel production apparatus according to

[15] , comprising: a combustion furnace for burning combustible gas generated from the biomass molded body; and an introduction section for introducing exhaust gas generated in the combustion furnace as the heating fluid into a hot gas flow path between the kiln body and the outer cylinder.

[17] A biomass solid fuel production apparatus according to any one of [1] to

[16] , wherein a fluid flow path for heating the biomass molded body is formed inside at least one of the plurality of first lifter blades.

[18] A biomass solid fuel production apparatus according to any one of [1] to

[17] , wherein the first heating zone is a region for heating the biomass molded body to a temperature lower than the dew point, and the second heating zone is a region for heating the biomass molded body to a temperature higher than the dew point and then carbonizing it.

[19] The biomass solid fuel manufacturing apparatus according to any one of [1] to

[18] , wherein the first heating zone includes a region for heating the biomass molded body until it reaches the dew point, and the second heating zone is a region for heating the biomass molded body heated in the first heating zone to a temperature higher than the dew point to carbonize it.

[20] A method for manufacturing a biomass solid fuel using the manufacturing apparatus according to any one of [1] to

[19] , comprising the steps of introducing the biomass molded body into the rotary kiln and heating the biomass molded body in heating zones including the first heating zone and the second heating zone to carbonize it.

[21] The method for manufacturing a biomass solid fuel according to

[20] , wherein the first heating zone in the step includes a region for heating the biomass molded body until it reaches the dew point.

[0112] 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G, 10H, 10I, 10J, 10K, 10L, 10M, 10N... Rotary kiln, 12... Kiln body, 13... Inner surface, 14... Outer cylinder, 15, 16... Rollers, 17... Hot gas flow path, 20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20J, 20K, 20L, 20M... Bent blade, 21... First lifter blade, 22... Second lifter blade, 23, 24... Non-bent blade, 23a... Split blade, 25... Protrusion, 26, 27, 28... Non-bent Curved blade, 30... Outlet section, 32... Outlet valve, 33... Gas outlet, 40... Combustion furnace, 41, 42, CA... Flow path, 43... Gas introduction section, 44... Burner, 50... Introduction section, 51... Biomass molded body, 53... Biomass solid fuel, 100... Manufacturing equipment, C... Center of rotation, EG... Exhaust gas, H1... First heating zone, H2... Second heating zone, IS... Inclined section, ISa, IS1... First part, ISb, IS2... Second part, PL... Reference line, r... Direction of rotation, SD... Plate-shaped member, SL... Slit, Z1... First non-heated zone, Z2... Second non-heated zone, α... First holding section, β... Second holding section.

Claims

1. A biomass solid fuel manufacturing apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, wherein the plurality of first lifter blades and the plurality of second lifter blades are configured such that the amount of biomass molded body scraped up per unit length of the kiln body is greater in the first heating zone than in the second heating zone.

2. The biomass solid fuel production apparatus according to claim 1, wherein the plurality of first lifter blades include a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion provided closer to the center of rotation than the base portion and including a portion that is inclined in the direction of rotation.

3. The angle θ between the base and the portion inclined in the rotational direction when viewed in the radial cross-section of the kiln body. １ The biomass solid fuel production apparatus according to claim 2, wherein the temperature is 20° or more and less than 180°.

4. The biomass solid fuel production apparatus according to claim 1, wherein the plurality of first lifter blades include a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, a first portion adjacent to the base portion and inclined in the direction of rotation, and a second portion provided closer to the center of rotation than the first portion and inclined in the direction of counter-rotation.

5. The apparatus for producing biomass solid fuel according to claim 4, wherein, when viewed in the direction of rotation, the plurality of bent blades, including a first bent blade and a second bent blade located forward in the direction of rotation of the first bent blade, are configured such that at least a portion of the biomass molded body scraped up by a first holding portion α formed by the base and first portion of the first bent blade falls into a second holding portion β formed by the base, first portion and second portion of the second bent blade.

6. The apparatus for producing biomass solid fuel according to claim 4, wherein, when viewed in the direction of rotation, the plurality of bending blades, including a first bending blade and a second bending blade located forward of the first bending blade in the direction of rotation, are configured such that at least a portion of the biomass molded body scraped up by a first holding portion α formed by the base and the second portion of the first bending blade falls toward the second portion of the second bending blade.

7. A biomass solid fuel manufacturing apparatus comprising a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, and the plurality of first lifter blades comprises a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation, and an inclined portion including a portion that is inclined in the counter-rotation direction closer to the center of rotation than the base portion.

8. The angle θ between the base and the portion inclined in the counter-rotational direction when viewed in the radial cross-section of the kiln body. ３ The biomass solid fuel production apparatus according to claim 7, wherein the temperature is between 20° and 90°.

9. The plurality of first lifter blades include the bent blades and the non-bent blades, and the average value of the length of the bent blades along the radial direction of the kiln body is L. ２０ , and the average value of the length of the non-bent blade along the radial direction is L ２３ When that is the case, L ２０ > L ２３ The apparatus for producing biomass solid fuel according to any one of claims 2 to 8.

10. A biomass solid fuel production apparatus according to any one of claims 1 to 8, wherein when LF is the average value of the lengths of the plurality of first lifter blades along the radial direction of the kiln body, and LS is the average value of the lengths of the plurality of second lifter blades along the radial direction, LF > LS.

11. The biomass solid fuel production apparatus according to any one of claims 1 to 8, wherein the number of the plurality of first lifter blades is greater than the number of the plurality of second lifter blades.

12. A biomass solid fuel manufacturing apparatus equipped with a rotary kiln, wherein the kiln body of the rotary kiln comprises a first heating zone having a plurality of first lifter blades for heating a biomass molded body, and a second heating zone having a plurality of second lifter blades for further heating the biomass molded body heated in the first heating zone, and satisfies one or both of the following (a) and (b): (a) When LF is the average value of the lengths of the plurality of first lifter blades along the radial direction of the kiln body, and LS is the average value of the lengths of the plurality of second lifter blades along the radial direction, LF > LS. (b) The number of the plurality of first lifter blades is greater than the number of the plurality of second lifter blades.

13. The biomass solid fuel production apparatus according to claim 12, wherein the plurality of first lifter blades include a plurality of bent blades having a base portion extending from the inner circumferential surface of the kiln body toward the center of rotation and an inclined portion including a portion that is inclined in the rotational direction closer to the center of rotation than the base portion.

14. The apparatus for producing biomass solid fuel according to any one of claims 1 to 8, 12, and 13, wherein the plurality of first lifter blades are configured to consist of a plurality of lifter blades of different types, each having a different amount of the biomass molded body to be scraped up, arranged periodically along the circumferential direction.

15. The apparatus for producing biomass solid fuel according to any one of claims 1 to 8, 12, and 13, wherein the rotary kiln is an externally heated rotary kiln having an outer cylinder outside the kiln body, and the first heating zone and the second heating zone heat the biomass molded body introduced into the kiln body by a heating fluid flowing between the kiln body and the outer cylinder.

16. A biomass solid fuel manufacturing apparatus according to claim 15, comprising: a combustion furnace for burning combustible gas generated from the biomass molded body; and an introduction unit for introducing exhaust gas generated in the combustion furnace as the heating fluid into a hot gas flow path between the kiln body and the outer cylinder.

17. A biomass solid fuel production apparatus according to any one of claims 1 to 8, 12, and 13, wherein a fluid channel for heating the biomass molded body is formed inside at least one of the plurality of first lifter blades.

18. The apparatus for producing biomass solid fuel according to any one of claims 1 to 8, 12, and 13, wherein the first heating zone is a region in which the biomass molded body is heated to a temperature lower than the dew point, and the second heating zone is a region in which the biomass molded body is heated to a temperature higher than the dew point after reaching the dew point to carbonize it.

19. The apparatus for producing a biomass solid fuel according to any one of claims 1 to 8, 12, and 13, wherein the first heating zone includes a region for heating the biomass molded body until it reaches the dew point, and the second heating zone is a region for heating the biomass molded body heated in the first heating zone to a temperature higher than the dew point to carbonize it.

20. A method for producing a biomass solid fuel using a manufacturing apparatus according to any one of claims 1 to 8, 12, and 13, comprising the steps of introducing the biomass molded body into the rotary kiln and heating the biomass molded body in heating zones including the first heating zone and the second heating zone to carbonize it.

21. The method for producing a biomass solid fuel according to claim 20, wherein the first heating zone in the step includes a region for heating the biomass molded body until it reaches a dew point.

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