Abstract: In order to evaluate the compatibility of coals used in coke production and to produce cokes with desired strength by blending coals in consideration of the compatibility, the invention provides a technique which evaluates the adhesion strength obtained when two kinds of coals are carbonized based. on properties of the coals. Surface tensions of two kinds of semicokes obtained by heat treating two kinds of coals are measured. Based on the difference between the two measured values of surface tension, the quality of the adhesiveness between the two kinds of coals is evaluated.

Abstract: In order to evaluate the compatibility of coals used in coke production and to produce cokes with desired strength by blending coals in consideration of the compatibility, the invention provides a technique which evaluates the adhesion strength obtained when two kinds of coals are carbonized based on properties of the coals. Surface tensions of two kinds of semicokes obtained by heat treating two kinds of coals are measured. Based on the difference between the two measured values of surface tension, the quality of the adhesiveness between the two kinds of coals is evaluated.

Abstract: There is provided a method for blending coals for coke production, in which the strength of coke produced from a coal blend serving as a raw material is estimated using a physical property that has not been taken into consideration in the past as an index, so that the method is capable of suppressing an increase in the raw material cost of the coal blend and increasing the strength of coal. Two or more coal brands are blended together to provide a coal blend for coke production. When the two or more coal brands are blended together, the coal brands and the blending ratio of the coal brands are determined using the surface tension of each of the coal brands subjected to heat treatment, the surface tension serving as a control index.

Abstract: A method for manufacturing coke having a high strength and excellent extrusion capability. The method includes a preparing step of blending two or more coal brands to prepare a coal blend, a stirring and mixing step of stirring and mixing the coal blend to disintegrate at least a part of pseudo-particles that have been formed by agglomeration of coal particles in the coal blend, and a carbonizing step of charging the stirred and mixed coal blend into a coke oven to carbonize the stirred and mixed coal blend. Additionally, a mixing apparatus is used in the stirring and mixing step that has a capability of controlling a degree of mixing of the coal blend to be 0.85 or more at 60 seconds after start of a mixing operation. The degree of mixing is calculated by the following equation (1): degree of mixing=(?C0??C)/(?C0??Cf)??(1).

Abstract: Method for preparing coal for coke making includes controlling particles size of coal or caking additive before arriving at the plant so particles content having diameter of 6 mm or more in the coal or caking additive reaches 30% by mass or less when the coal or caking additive has permeation distance of 15 mm or more. In another method, the relationship between a critical permeation distance and Gieseler maximum fluidity is obtained using permeation distances and Gieseler maximum fluidity values of one or more brands of coal or caking additive, particles size of coal or caking additive is controlled before arriving at the plant so particles content having diameter of 6 mm or more in coal or caking additive reaches 30% by mass or less when permeation distance of coal or caking additive is larger or equal to a critical permeation distance calculated from the Gieseler maximum fluidity.

Abstract: A coke manufacturing method includes preparing blended coal by blending coal of at least two types, stirring and mixing the blended coal so as to disintegrate at least a part of pseudo-particles in the blended coal that have been formed by agglomeration of coal particles, and charging the blended coal after stirring and mixing into a coke oven and carbonizing the blended coal so as to manufacture coke.

Abstract: A document camera includes a base, a first arm assembled to the base, a second arm assembled to the first arm, and a camera head assembled to the second arm. The first arm is pivotable between a parallel extending position and a raised position. The second arm is pivotable between a juxtaposed position and a raised position and between the raised position and a parallel extending position. The camera head is pivotable between a juxtaposed position and a position where the camera head is raised from the second arm. When the document camera is to be folded, the first arm is set to the parallel extending position, the second arm and the camera head are to the respective juxtaposed positions. When the document camera has been folded, upper surfaces of the first and second arms and the camera head are substantially coplanar.

Abstract: A coal mixture is provided that maintains a high level of coke strength after carbonization, even where coal having an excessively large permeation distance is used in a large amount. The coal mixture includes large-permeation-distance coal and permeation-distance-decreasing coal. The permeation-distance-decreasing coal has a mean maximum vitrinite reflectance Ro of 1.25% or more and a total inert amount TI of 30 vol. % or less. The blending ratio of the permeation-distance-decreasing coal in the coal mixture is in a range derived by multiplying the blending ratio of the large-permeation-distance coal by 0.25 or more and 3.0 or less.

Abstract: Coke is manufactured by blending two or more kinds of coal to form a coal blend and by carbonizing the coal blend. Interfacial tension among coal kinds is used as a control index for determining the blending ratio of each coal when forming the coal blend. It is possible to increase the strength of coke without increasing the material cost of a coal blend.

Abstract: A method for evaluating thermal plasticity of coals and caking additives includes packing a coal or a caking additive into a vessel to prepare a sample 1; arranging a through-hole material 2 having through-holes from top to bottom surfaces, onto the sample 1; heating the sample 1 at a predetermined heating rate while maintaining a constant volume of or while applying a constant load onto the sample 1 and the through-hole material 2; measuring the permeation distance with which the molten sample has permeated into the through-holes; and evaluating thermal plasticity of the sample using the measured value. Alternatively, a method involves heating the sample 1 at a predetermined heating rate while maintaining the sample 1 and the through-hole material 2 in a constant volume; measuring the pressure of the sample that is transmitted via the through-hole material 2; and evaluating thermal plasticity of the sample using the measured value.

Abstract: Provided are, by using an index with which the influence on the strength of coke can be evaluated, a method for evaluating a weathering degree of coal and a coking property of weathered coal within the ranges in which the weathering degree and coking property cannot be determined by using conventional methods, and a method for controlling the weathering degree of coal with which it is possible to add weathered coal to a coal blend to be used for producing coke without decreasing the strength of coke by using the index. The weathering degree of coal is evaluated by using the surface tension of semicoke which is prepared by performing a heat treatment on weathered coal as an index. The weathering degree of each brand of coal is controlled so that the interfacial tension ?inter of a semicoke blend which is prepared by blending the plural brands of semicoke in accordance with the proportions is 0.03 mN/m or lower.

Abstract: A coke manufacturing method includes preparing blended coal by blending coal of at least two types, stirring and mixing the blended coal so as to disintegrate at least a part of pseudo-particles in the blended coal that have been formed by agglomeration of coal particles, and charging the blended coal after stirring and mixing into a coke oven and carbonizing the blended coal so as to manufacture coke.

Abstract: A method for estimating the thermal plasticity of coal and a caking additive by observing the thermal plasticity of coal and a caking additive under the condition that sufficiently simulates an environment surrounding thermal plastic coal and a caking additive in a coke oven and to provide a method for preparing coal of a brand having a specified quality by making clear the required quality of a coal brand which can be ideally used for manufacturing high-strength coke by using the estimation method. A method for preparing coal for coke making, the method including adjusting a permeation distance of one or more kinds of coal to a specified value or less when plural coal brands are blended as materials to be used for coke making is used.

Abstract: There is provided a method for blending coals for coke production, in which the strength of coke produced from a coal blend serving as a raw material is estimated using a physical property that has not been taken into consideration in the past as an index, so that the method is capable of suppressing an increase in the raw material cost of the coal blend and increasing the strength of coal. Two or more coal brands are blended together to provide a coal blend for coke production. When the two or more coal brands are blended together, the coal brands and the blending ratio of the coal brands are determined using the surface tension of each of the coal brands subjected to heat treatment, the surface tension serving as a control index.

Abstract: Coke is manufactured by blending two or more kinds of coal to form a coal blend and by carbonizing the coal blend. Interfacial tension among coal kinds is used as a control index for determining the blending ratio of each coal when forming the coal blend. It is possible to increase the strength of coke without increasing the material cost of a coal blend.

Abstract: In order to evaluate the compatibility of coals used in coke production and to produce cokes with desired strength by blending coals in consideration of the compatibility, the invention provides a technique which evaluates the adhesion strength obtained when two kinds of coals are carbonized based on properties of the coals. Surface tensions of two kinds of semicokes obtained by heat treating two kinds of coals are measured. Based on the difference between the two measured values of surface tension, the quality of the adhesiveness between the two kinds of coals is evaluated.

Abstract: Method for preparing coal for coke making includes controlling particles size of coal or caking additive before arriving at the plant so particles content having diameter of 6 mm or more in the coal or caking additive reaches 30% by mass or less when the coal or caking additive has permeation distance of 15 mm or more. In another method, the relationship between a critical permeation distance and Gieseler maximum fluidity is obtained using permeation distances and Gieseler maximum fluidity values of one or more brands of coal or caking additive, particles size of coal or caking additive is controlled before arriving at the plant so particles content having diameter of 6 mm or more in coal or caking additive reaches 30% by mass or less when permeation distance of coal or caking additive is larger or equal to a critical permeation distance calculated from the Gieseler maximum fluidity.

Abstract: A method for evaluating thermal plasticity of coals and caking additives includes packing a coal or a caking additive into a vessel to prepare a sample 1; arranging a through-hole material 2 having through-holes from top to bottom surfaces, onto the sample 1; heating the sample 1 at a predetermined heating rate while maintaining a constant volume of or while applying a constant load onto the sample 1 and the through-hole material 2; measuring the permeation distance with which the molten sample has permeated into the through-holes; and evaluating thermal plasticity of the sample using the measured value. Alternatively, a method involves heating the sample 1 at a predetermined heating rate while maintaining the sample 1 and the through-hole material 2 in a constant volume; measuring the pressure of the sample that is transmitted via the through-hole material 2; and evaluating thermal plasticity of the sample using the measured value.

Abstract: A method for estimating the thermal plasticity of coal and a caking additive by observing the thermal plasticity of coal and a caking additive under the condition that sufficiently simulates an environment surrounding thermal plastic coal and a caking additive in a coke oven and to provide a method for preparing coal of a brand having a specified quality by making clear the required quality of a coal brand which can be ideally used for manufacturing high-strength coke by using the estimation method. A method for preparing coal for coke making, the method including adjusting a permeation distance of one or more kinds of coal to a specified value or less when plural coal brands are blended as materials to be used for coke making is used.