Abstract: A method of producing a coal mixture includes blending a plurality of coals, wherein formula (1) and formula (2) are satisfied: ? calc = ? i N ? ? i × x i ( 1 ) ?calc?1.2×10?10 (mol/g-coal)??(2) wherein ?calc is a hydrogen ion release capacity per unit mass (mol/g-coal) of the coal mixture, ?i is the hydrogen ion release capacity per unit mass (mol/g-coal) of a coal i, xi is a blending ratio of the coal i blended in the coal mixture, and N is a total number of brands of coal contained in the coal mixture.

Abstract: A method for preparing a coal, which is used alone or in combination with at least one other coal, or a caking additive as a raw material for coke production. The method includes, before the coal or caking additive is delivered to a coke plant, adjusting a grain size such that the amount of grains with a grain size of 6 mm or more in the coal or caking additive satisfies at least one of a degree of entanglement (a - b)/a of 0.20 or more and a portion having a height a of 30 mm or more is 30% or less by mass. The height a is a height of semicoke adhering to a stirrer, the semicoke formed by heating the coal or caking additive in a container while rotating the stirrer, and the height b is a height of the semicoke on an inner wall of the container.

Abstract: A method for evaluating the thermoplasticity of a coal or a caking additive with an apparatus including a container for coal and a stirrer located in the container. The method includes estimating a permeation distance of the coal or caking additive from a value indicating a shape of semicoke formed by rotating the stirrer while heating the coal or caking additive and from a correlation between the value indicating the shape of the semicoke and the permeation distance of the coal or caking additive.

Abstract: A method of producing a coal blend by blending plural brands of coal to produce a coal blend includes letting a surface tension of coal when inert material is assumed to be 100 vol % be ?100, and letting a surface tension of coal when reactive material is assumed to be 100 vol % be ?0, determining ?0 of coal; among brands of coal 1, 2, . . . i, . . . , and n to be blended in a coal blend, specifying coal i in which ?100 is outside of ?0; measuring TI of coal i; and determining a blending ratio of coal i such that w calculated by formula (1) is 20.4 mass % or less w=?(xi×TIi)??(1).

Abstract: A method of estimating a surface tension of coal includes subjecting a surface tension, a physical property value representing a coal rank, and a total inert content of each of different brands of coal to multiple regression analysis to determine in advance a regression equation including the surface tension of coal as an objective variable and the physical property value and the total inert content as explanatory variables; and measuring the physical property value and the total inert content of a coal of which the surface tension is to be estimated, and calculating the surface tension of the coal with the measured physical property value and the measured total inert content, and the regression equation.

Abstract: A method of estimating a surface tension of coal inert material includes determining in advance a first relational expression representing a relationship between a surface tension of coal inert material and a physical property value representing a coal rank; and measuring the physical property value representing the coal rank of a coal for which the surface tension of coal inert material is to be estimated, and calculating the surface tension of the coal inert material by using the measured physical property value representing the coal rank and the first relational expression.

Abstract: Methods for evaluating whether there is a probability that coal will reduce the strength of coke using an apparatus including a stirrer. A degree of entanglement (a?b)/a represented by the heights a and b, or the height a only, is used as an evaluation index for coal, where a height of the semicoke on an inner wall of the container is represented by b, and a height of the semicoke on the stirrer is represented by a. Semicoke formed from heated coal is formed in the container using the degree of entanglement as an evaluation index.

Abstract: A method of producing a coal mixture includes blending a plurality of coals, wherein formula (1) and formula (2) are satisfied: ? calc = ? i N ? ? i × x i ( 1 ) ?calc?1.2×10?10 (mol/g-coal)??(2) wherein ?calc is a hydrogen ion release capacity per unit mass (mol/g-coal) of the coal mixture, al is the hydrogen ion release capacity per unit mass (mol/g-coal) of a coal i, xi is a blending ratio of the coal i blended in the coal mixture, and N is a total number of brands of coal contained in the coal mixture.

Abstract: A method of evaluating coal includes preparing coal samples having different inert amounts by pulverizing one brand of coal; measuring the inert amounts of the respective coal samples and measuring surface tensions of semi-coke obtained by heat treating the respective coal samples; and determining a regression line based on the inert amounts and the surface tensions and evaluating the coal by using, as an index, a ratio of a variation in the surface tensions to a variation in the inert amounts as determined from the regression line.

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: A method for accurately measuring the thermoplasticity of a coal whose thermoplasticity has been difficult to evaluate and determining whether the coal that is to be measured does not significantly reduce the coke strength when used for a coal blend is disclosed. Also disclosed is a method for evaluating a coal used as a raw material for coke and includes using a physical property value relating to a thermoplasticity of a coal as an index for evaluating the coal, wherein a primary or secondary amine including an aromatic ring have been added to the coal, thereby enhancing the thermoplasticity of the coal.

Abstract: A document camera includes a base, a monitor display mounted on the base, a first arm, a second arm, and a camera head. The first arm is mounted to the base so as to be pivotable in a right-left direction. The second arm is mounted to the first arm so as to be pivotable in the right-left direction. The camera head is mounted to the second arm so as to be pivotable in the right-left direction. The arms and the camera head are laid into respective laid positions when the document camera is not in use. The arms and the camera head are raised into respective standing positions when the document camera is in use. When laid into the respective laid positions, the arms and the camera head are fit within an upper surface of the base, and the monitor display is substantially covered by the first arm.

Abstract: A document camera includes a base, a monitor display mounted on the base, a first arm, a second arm, and a camera head. The first arm is mounted to the base so as to be pivotable in a right-left direction. The second arm is mounted to the first arm so as to be pivotable in the right-left direction. The camera head is mounted to the second arm so as to be pivotable in the right-left direction. The arms and the camera head are laid into respective laid positions when the document camera is not in use. The arms and the camera head are raised into respective standing positions when the document camera is in use. When laid into the respective laid positions, the arms and the camera head are fit within an upper surface of the base, and the monitor display is substantially covered by the first arm.

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: 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: 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 method for accurately measuring the thermoplasticity of a coal whose thermoplasticity has been difficult to evaluate and determining whether the coal that is to be measured does not significantly reduce the coke strength when used for a coal blend is disclosed. Also disclosed is a method for evaluating a coal used as a raw material for coke and includes using a physical property value relating to a thermoplasticity of a coal as an index for evaluating the coal, wherein a primary or secondary amine including an aromatic ring have been added to the coal, thereby enhancing the thermoplasticity of the coal.

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.