JP5714165B1 - Method for producing coking coal and method for producing coke - Google Patents

Abstract

The present invention provides a method for producing molded coke that can stably produce molded coke having high strength. A method for producing a molded coke, comprising: a molding step in which coal and a binder are kneaded and molded to produce a molded coal; and a dry distillation step in which the coal is carbonized to obtain a molded coke. Before the process, using coal and binder, it has a preparatory process to predict the change in the expansion rate of the coal formation due to the binder content and the change in the expansion rate of the coal formation due to the molding pressure. In the process, there is provided a method for producing molded coke, in which a molded coal having a predicted expansion coefficient y based on a predicted result of the preparation process is 1 or more. [Selection figure] None

Description

  The present invention relates to a method for producing coal and a method for producing molded coke.

  In recent years, with the rapid increase in steel demand in Asian countries such as China and India, the price of coal used in the production of iron-making coke has soared. Economically minable coal reserves (recoverable reserves) are said to be about 847.4 billion tons. Among these, high-grade coal suitable for the production of coke has a limited production area and the reserves are only about 10% of the total. For this reason, there is a concern that it will be depleted in the future.

  Under such circumstances, technology development for producing high-quality molded coke using low-grade coal with relatively rich reserves has been carried out. For example, Patent Document 1 attempts to improve the strength of molded coke by adjusting the coal particle size according to the coal cohesive strength index and volatile matter.

Japanese Patent Laid-Open No. 7-197030

  However, the strength of the molded coke produced by the conventional technique is still not sufficient. In addition, since the strength of the molded coke varies depending on the type and properties of the raw material, it is difficult to stably manufacture the molded coke having high strength. Such a phenomenon was particularly remarkable when low-grade coal was used. For this reason, even if it is a case where low grade coal is used, it is calculated | required to establish the technique which can manufacture stably the shaping | molding coke which has sufficiently high intensity | strength.

  This invention is made | formed in view of such a situation, and it aims at providing the manufacturing method of the molding coke which can manufacture the molding coke which has high intensity | strength stably in one side surface. . In addition, another object of the present invention is to provide a method for producing molded coal that can stably produce molded coke having high strength.

  The present inventors have studied various measures for improving the strength of molded coke. As a result, it has been found that the properties of the raw materials used for producing the molded coke and the production conditions for producing the molded coke have a great influence on the strength of the molded coke.

  Therefore, in the present disclosure, a method for producing a molded coke having a molding step of kneading and molding coal and a binder to produce a molded coal, and a dry distillation step of carbonizing the molded coal to obtain a molded coke, Before the molding process, using coal and a binder, it has a preparation process to predict the change in the expansion rate of the coal formation due to the binder content and the change in the expansion rate of the coal formation due to the molding pressure. In the molding process, there is provided a method for producing molded coke, in which a molded coal having a predicted expansion coefficient y based on a predicted result of the preparation process is 1 or more.

  In the said manufacturing method, it has the preparatory process which estimates the change of the expansion coefficient of the coal char by the content rate of a binder, and the change of the expansion coefficient of the coal char by a molding pressure before a formation process. This is based on the knowledge of the present inventor who has found that the binder content and the molding pressure of the coal have a high correlation with the expansion rate of the coal. For this reason, the expansion rate of the coal can be predicted with high accuracy.

  Here, the expansion coefficient of the coal is a numerical value indicating the volume change after the carbonization with respect to that before the carbonization when the coal is carbonized under the normal carbonization conditions. For example, if the expansion coefficient is 1 or more, it means that the volume after dry distillation is equal to or higher than the volume before dry distillation. On the other hand, if the expansion coefficient is less than 1, it means that the volume after dry distillation is smaller than the volume before dry distillation. Normally, when carbonized coal is carbonized, gas begins to escape from the coal contained in the coal at around 300 ° C. And in the temperature range of 400-600 degreeC, the generation amount of the gas from coal becomes large, and the shrinkage amount of forming coal becomes large in connection with it.

  On the other hand, the binder contained in the charcoal expands as the temperature rises. In the said manufacturing method, since the predicted value of the expansion coefficient of coal is 1 or more, the amount of voids in the molded coke obtained by dry distillation can be reduced to form a densely filled molded coke. Therefore, a molded coke having high strength can be produced.

  By the way, the expansion coefficient of the coal is affected by the types of coal and binder contained in the coal, and the contents thereof. In addition, the expansion coefficient of the coal is affected by the molding pressure during the production of the coal. That is, when the molding pressure is low, the ratio of voids in the coal is increased, so that the expansion rate of the coal is low during dry distillation. On the other hand, when the molding pressure is increased, the proportion of voids in the coal is reduced, so that the expansion rate of the coal is increased during dry distillation.

  In the manufacturing method described above, it is possible to predict the expansion coefficient of the coal with high accuracy by predicting the change in the expansion coefficient due to the binder content and the molding pressure. And in the molding process, the charcoal in which the predicted value of the expansion coefficient calculated | required based on the prediction result of this prediction process is 1 or more is produced. Therefore, the molded coke which has high intensity stably can be manufactured. Such a molded coke is useful as a molded coke for a blast furnace that is required to have a stable high strength. In addition, it is preferable that the measured value of the expansion coefficient of the coal char obtained in the molding step is 1 or more.

  In the above manufacturing method, the volatile content of coal kneaded with the binder may be 20% by mass or less. By using coal with a small volatile content, the amount of gas generated from coal during dry distillation is reduced. This makes it easier to set the expansion coefficient to 1 or more.

The preparation step may include the following first step and second step.
(1) Prepare a plurality of kneaded material samples having different binder contents from coal and binder, and use the first molded coal sample obtained by molding the kneaded material sample at a predetermined molding pressure. A first step of obtaining a change amount w of the expansion coefficient accompanying a change in the rate and obtaining a ratio A [1 / mass%] of the change amount w with respect to the binder content.
(2) Using a plurality of second molded coal samples obtained by molding a kneaded sample containing coal and a binder at different molding pressures, a change amount z of an expansion coefficient accompanying a change in molding pressure is obtained. A second step of obtaining a ratio C [cm / ton or cm ² / ton] of the change amount z with respect to a difference from a predetermined molding pressure.

Using the ratios A and C obtained in the first step and the second step, the predicted value y of the expansion rate of the formed coal may be predicted by the following formula (1).
y = x + A × b + C × (d-d 0) (1)
In formula (1), x represents the expansion rate of coal molded at a predetermined molding pressure, b represents the binder content (mass%) in the molding process, and d represents the molding pressure (ton / cm in the molding process). Or ton / cm ² ), and d ₀ represents a predetermined molding pressure (ton / cm or ton / cm ² ). In the equation (1), the unit of the molding pressure of d and d ₀ are the same.

  At the said 1st process, the ratio A [1 / mass%] of the variation | change_quantity w with respect to the content rate of a binder is calculated | required using the some 1st shaping | molding charcoal sample from which content of a binder differs. In the second step, with respect to the difference between the molding pressure and a predetermined molding pressure (hereinafter, also referred to as “reference molding pressure”), the second molding charcoal sample obtained by molding at a different molding pressure is used. The ratio C of the change amount z is obtained. And based on these ratios A and C and the difference between the binder content in the molding step, the molding pressure, and the reference molding pressure, the coefficient of expansion of the coal is predicted. Therefore, it is possible to predict the expansion coefficient of the coal with higher accuracy, and it is possible to manufacture the molded coke having higher strength more stably.

  Further, in the present disclosure, a method for producing a coal having a molding process in which coal and a binder are kneaded and molded to produce a coal, and before the molding process, using the coal and the binder, It has a preparatory process that predicts the change in the expansion coefficient of the charcoal due to the content rate and the change in the expansion coefficient of the coal char due to the molding pressure. In the molding process, the expansion coefficient is predicted based on the prediction result of the preparatory process. Provided is a method for producing coal, which produces coal having a value y of 1 or more.

  In the said manufacturing method, the expansion coefficient of a coal char is estimated with high precision, and the coal char with the predicted value y of the expansion coefficient of a coal char is 1 or more is produced. If such cast charcoal is dry-distilled, molded coke having high strength can be obtained stably. In other words, the coal obtained by the above-described method for producing coal is useful as coal for producing molded coke.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the molding coke which can manufacture the molding coke which has high intensity | strength stably, and the manufacturing method of coal char can be provided.

It is a flowchart of the manufacturing method of the shaping | molding coke which concerns on one Embodiment of this invention. It is a figure explaining the predicted value of the expansion coefficient of the coal char concerning one embodiment of the present invention. It is a schematic diagram which shows an example of the molding coke manufacturing equipment with which the manufacturing method of the molding coke which concerns on one Embodiment of this invention is applied.

  Hereinafter, a method for producing molded coke according to an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a flowchart of a method for producing molded coke according to the present embodiment. The method for producing molded coke shown in FIG. 1 includes the following steps.

(I) The 1st process which calculates | requires the variation | change_quantity w of the expansion coefficient of the coal coal accompanying the change of the content rate of a binder using the 1st coal sample produced using the kneaded material sample containing coal and a binder. (S1)
(Ii) Second step (S2) for obtaining a change amount z of the expansion coefficient of the coal with the change of the molding pressure, using the second coal sample produced by using the kneaded material sample containing coal and the binder. )
(Iii) A pretreatment step (S3) in which a pretreatment for heating the coal is performed to reduce the volatile content of the coal.
(Iv) Mixing step of kneading coal and binder to obtain a kneaded product (S4)
(V) Molding step of molding the kneaded material to produce molded charcoal (S5)
(Vi) Carbonization process of carbonizing coal to obtain molded coke (S6)

  As the coal, various varieties such as caking coal and non-caking coal can be used without particular limitation. In the production method of the present embodiment, even if non-caking coal is used, it is possible to produce molded coal that can produce molded coke having sufficiently high strength and molded coke that has sufficiently high strength. For this reason, while being able to raise the freedom degree of the selection of the kind of coal, the manufacturing cost of a coal and a molding coke can be reduced.

  When the particle size of coal is large, a pulverization step of pulverizing coal may be performed in advance. By the pulverization step, the particle size of the coal is set to 1.5 mm or less, for example. When pulverized powder having a large particle size is included, the particle size of coal may be adjusted by sieving.

The expansion coefficient x of coal in the present specification can be determined in accordance with “9. Expansibility test method (dilatometer method)” of JIS M 8801: 2004. Specifically, coal is pressure-molded into a rod shape at a predetermined pressure (reference molding pressure: d ₀ ), and inserted into a thin tube whose lower end is sealed. A piston having a predetermined load is inserted on the molded body inserted into the thin tube. The molded body is heated at a predetermined temperature increase rate using an electric furnace in a state where a piston load is applied. Production of a molded body may be performed using a double roll as in the molding conditions of the molding process described later, or may be performed by uniaxial pressing using a normal molding machine.

The rate of temperature increase can be appropriately set, for example, from a range of 1 to 10 ° C./min, and the maximum temperature can be set, for example, from a range of 400 to 600 ° C., for example. The displacement of the piston is determined from the position of the piston before and after heating. From the displacement of the piston, the volume change of the coal molding is obtained. When the volume of the molded body before heating is x ₀ and the volume of the coal after heating is x ₁ , the expansion coefficient x of the coal can be obtained by the following equation (2).
x = x ₁ / x ₀ (2)

  The expansion coefficient in the present specification is a numerical value indicating a volume change accompanying heating as a volume ratio (= volume after heating / volume before heating). The expansion coefficient can be obtained by using a method capable of measuring a volume change before and after heating. The measurement of the expansion coefficient is not limited to the method described above, and any method can be used without particular limitation as long as it is a method for measuring a volume change accompanying heating.

  In 1st process S1, the several kneaded material sample from which the content rate of a binder differs is first prepared using the above-mentioned coal and binder. The binder has a function of binding granular coal, and includes at least one selected from the group consisting of ordinary coal tar, petroleum pitch, coal pitch, soft pitch, polyvinyl alcohol, petroleum asphalt, and waste oil. . A plurality of kneaded material samples having different binder contents relative to the total of coal and binder are prepared. The content of the binder in the kneaded material sample may be, for example, 5 to 20 mass% or 5 to 15 mass%.

The prepared plurality of kneaded samples are molded by pressurizing at a predetermined pressure (d ₀ ) in the same manner as the measurement of the expansion coefficient x of coal, and a plurality of first molded coal samples having different binder contents. Is made. This predetermined molding pressure (d ₀ ) is set as a reference molding pressure.

  The expansion coefficient of the obtained plurality of first coal samples is obtained. This expansion coefficient can be determined in accordance with “9. Expandability test method (dilatometer method)” of JIS M 8801: 2004, similarly to the expansion coefficient x of coal.

When the volume of the first coal char sample before heating is a ₀ and the volume of the first coal char sample after heating is a ₁ , the expansion coefficient w ₀ of the _first coal char sample is a ₁ / a It is obtained by calculating ₀ . By subtracting the expansion coefficient x of the coal from the expansion coefficient w _0, a change amount w of the expansion coefficient of the first coal sample is obtained. Then, the amount of change in the expansion rate per 1 mass% of the binder content is calculated from the value of the amount of change w in the expansion rate of the plurality of first coal samples and the content rate b of the binder by the following equation (3). In this way, the ratio A [1 / mass%] of the amount of change in the expansion coefficient of the coal coal relative to the binder content is determined.
A = w / b (3)

  In the formula (3), w represents the amount of change in the expansion coefficient of the formed coal due to the binder content, and b represents the binder content (mass%). A is a coefficient that may vary depending on the type of binder, for example, 0.01 to 0.05. The binder content b is, for example, 5 to 20% by mass. The change amount w of the expansion coefficient is, for example, 0.05 to 0.4.

  In addition, the ratio A of the variation | change_quantity of the expansion rate of the forming coal with respect to the content rate of a binder may be calculated | required as mentioned above, and may be calculated | required by regression analysis. For example, the ratio A may be obtained by a single regression analysis in which the binder content b is an independent variable and the change w of the expansion coefficient associated with the binder content b is a dependent variable.

In the second step S2, first, a kneaded material sample containing coal and a binder is molded at a predetermined pressure (d ₀ ) and a molding pressure d different from this, and a plurality of second samples having different molding pressures are used. A sample of charcoal is prepared. The content rate of the binder in a kneaded material sample can be arbitrarily set, for example in the range of 5-20 mass%. However, the binder content of each kneaded material sample used for the production of the plurality of second formed charcoal samples is the same.

The molding pressure can be in the range of, for example, ^{2 to} 6 ton / cm as the linear pressure and 1 to 1.9 ton / cm ^{2 as} the surface pressure. In this way, a plurality of second coal char samples can be obtained. It is preferable to produce the second coal-coal sample by the same method as the molding method for measuring the expansion coefficient of coal, the molding method for the first coal-coal sample, and the molding method in the molding process. Thereby, the expansion rate of the coal can be predicted more accurately.

The expansion coefficient of the obtained second plurality of charcoal samples is obtained. This expansion coefficient is obtained in accordance with “9. Expandability test method (dilatometer method)” of JIS M 8801: 2004, similarly to the expansion coefficient x of the coal and the expansion coefficient w _{0 of} the first cast coal sample. Can do.

When the volume of the second coal char sample before heating is c ₀ and the volume of the second coal char sample after heating is c ₁ , the expansion coefficient z ₀ of the second coal char sample is c ₁ / c It is obtained by calculating ₀ . Then, from the difference between the expansion coefficient change amount z and the molding pressure d and the reference molding pressure of the plurality of second molding charcoal samples, the amount of expansion coefficient change per molding pressure 1 ton / cm (or 1 ton / cm ² ) is calculated. It calculates by following formula (4). In this way, the molding pressure of d and the reference shaping pressure ratio of the amount of change in the expansion rate of the molded coal for the difference between _{d 0} C [cm / ton (or ^cm 2 / ton)] is obtained.
C = z / (d−d ₀ ) (4)

In the formula (4), z represents the amount of change in expansion coefficient associated with the difference between the molding pressure and the reference molding pressure, d represents the molding pressure, and d ₀ represents the reference molding pressure. C is, for example, 0.01 to 0.05 (1 / mass%). d is, for example, 2 to 6 ton / cm (1.1 to 1.9 ton / cm ² ). The change amount z of the expansion coefficient is, for example, 0 to 0.2. d ₀ is, for example, 2 to 4 ton / cm (1.1 to 1.5 ton / cm ² ).

In addition, the ratio C of the change amount of the expansion coefficient of the forming coal with respect to the difference between the forming pressure and the reference forming pressure may be obtained as described above or may be obtained by regression analysis. For example, a single regression analysis in which the difference (d−d ₀ ) between the molding pressure and the reference molding pressure is an independent variable, and the change amount z of the expansion rate of the coal is associated with the difference between the molding pressure and the reference molding pressure. The ratio C may be obtained by

FIG. 2 is a diagram illustrating the relationship between the expansion coefficient x of coal and the predicted value y of the expansion coefficient of coal. The predicted value y of the expansion rate of the coal is based on the difference between the predicted value (A × b) of the change in the expansion rate based on the expansion rate x of the coal and the content rate b of the binder, and the molding pressure and the standard molding pressure. It is represented by the sum of predicted values [C × (d−d ₀ )] of the change amount of the expansion coefficient. That is, the predicted value y of the expansion rate of the coal can be obtained by the following formula (1).

y = x + A × b + C × (d-d 0) (1)
The predicted value y of the expansion coefficient of the coal coal predicted by the equation (1) reflects the influence of both the binder content and the molding pressure in addition to the expansion coefficient x of the coal. For this reason, the expansion rate of the coal can be predicted with high accuracy. The first step S1 and the second step S2 described above can be performed as a preparation step.

  In pre-processing process S3, coal is heated to 400-700 degreeC, for example, is carbonized (preliminary carbonization), and the volatile matter of coal is reduced. In such pretreatment process S3, coal with high volatile content is heated and coal with low volatile content is prepared. For example, coal having a volatile content of 35% by mass or more is heated and dry-distilled to prepare coal having a volatile content of 20% by mass or less. In the pretreatment step S3, for example, coal having a volatile content of 3 to 20% by mass is prepared. By preparing such a volatile coal, a coal with an expansion rate of 1 or more can be easily obtained. However, even if the volatile content is outside the range of 3 to 20% by mass, a coal char having an expansion coefficient of 1 or more can be obtained by adjusting the binder content and / or the molding pressure.

  It is not essential to perform the pretreatment step S3. For example, when coal having a low volatile content (for example, 20% by mass or less) is used as a raw material, the pretreatment step may not be performed. In addition, the volatile matter in this specification is a dry base value measured in accordance with the “square electric furnace method” of JIS M 8812: 2006. Coking coal produced using powdered coke with reduced volatile matter can reduce the volatile matter released from the inside of the forming coal in the dry distillation step S6 described below. Thereby, the expansion coefficient of the coal is increased, and the strength of the molded coke can be improved. Moreover, pre-processing process S3 may be performed before 1st process S1 and 2nd process S2, and the 1st process and 2nd process may be performed using the coal which performed the above-mentioned pre-processing.

In the mixing step S4, the coal used in the first step S1 and the second step S2 and the binder are kneaded to obtain a kneaded product. At this time, the predicted value y of the expansion coefficient of the coal char obtained from the predicted value [A × b + C × (d−d ₀ )] of the change amount of the expansion coefficient of the coal char obtained in the first step S1 and the second step S2. The blending ratio of coal and binder is set so that can be 1 or more. Kneading of coal and binder can be performed using a normal kneader.

In the molding step S5, the kneaded material is molded to produce molded charcoal. As the molding machine, a double roll molding machine or a uniaxial pressure molding machine can be used. Molding is performed at a molding pressure d such that the predicted value y of the expansion coefficient of the coal coal predicted by the equation (1) can be 1 or more. The molding pressure d is in the range of, for example, ^{2 to} 6 ton / cm in terms of linear pressure and 1.1 to 1.9 ton / cm ^{2 in} terms of surface pressure. The mixing step S4 and the forming step S5 are performed so that the expansion rate of the forming coal in the dry distillation step S6, which is predicted using the ratios A and C obtained in the first step S1 and the second step S2, is 1 or more. Is called. In other words, the coal is produced with the binder content b and the molding pressure d such that the predicted value y of the expansion coefficient of the coal obtained by the formula (1) is 1 or more.

  It is preferable that the measured value of the expansion coefficient of the coal coal obtained by such a manufacturing method is 1 or more. If the expansion coefficient of the coal is 1 or more, the coke having a structure in which the amount of voids is small and densely packed can be obtained by dry distillation. Thereby, a molded coke having high strength can be obtained. The expansion coefficient of the coal can be determined in accordance with “9. Expansibility test method (dilatometer method)” of JIS M 8801: 2004, similarly to the method for measuring the expansion coefficient x of coal. The expansion coefficient of the coal is, for example, 1 to 1.2.

In the carbonization step S6, carbonized coal is carbonized to produce molded coke. Carbonization can be performed using a normal carbonization furnace such as a vertical shaft furnace, a coke oven, a tunnel kiln furnace or the like. In the dry distillation step, the temperature is raised by bringing the coal into contact with heating charcoal, and dry distillation is performed to obtain molded coke. The molded coke thus obtained has a stable and high strength. DI strength of molded coke which is measured in accordance with JIS K 2151 (drum strength) ^is expressed in ^DI _{0.99 15,} for example 80% or more.

DI ¹⁵⁰ ₁₅ is measured by the following procedure. 10 kg of molded coke having a particle size of 25 mm or more is placed in a drum testing machine having an inner diameter and a length of 1500 mm and blades having a height of 250 mm along the radial direction. Then, the drum tester is rotated 150 times at 15 rpm, and then sieved. The ratio (mass%) remaining on the 15 mm sieve by sieving is defined as DI ¹⁵⁰ ₁₅ .

In the method for producing the coking coal and coke, according to the present embodiment, an index called an expansion coefficient having a high correlation with the strength of the coke is adopted. The expansion rate is predicted based on the difference between the pressure and the molding pressure (d−d ₀ ). Since the binder content ratio b and the difference between the standard molding pressure and the molding pressure (d−d ₀ ) have a high correlation with the expansion ratio of the molding coal, according to the manufacturing method of the present embodiment, the expansion of the molding coal. The rate can be predicted with high accuracy. As a result, it is possible to produce a molded coke having a high strength stably, and a molded coal for producing a molded coke capable of producing such a molded coke.

  FIG. 3 is a schematic diagram showing an example of a continuous molding coke manufacturing facility to which the manufacturing method of the molding charcoal and molding coke of the present embodiment is applied. A continuous-type coke manufacturing facility 100 in FIG. 3 is provided on the downstream side of the coal-forming unit 10 and a coal-forming unit 10 that produces coal by press-molding a raw material containing coal and a binder. And a carbonization section 20 for producing carbonized coke for a gasification melting furnace by carbonizing carbon. Using such a continuous molded coke production facility 100, a method for producing molded coke can be implemented.

  The coal is introduced from the tank 11 into the primary pulverizer 12 and pulverized, and then introduced into the dryer 13. Here, you may reduce the water | moisture content contained in coal to 2-3 mass%. The coal dried by the dryer 13 is pulverized and atomized by the secondary pulverizer 14. After the atomization, a pretreatment for heating the coal to reduce the volatile matter may be performed. In the kneader 15, coal and a binder are kneaded to prepare a kneaded product. The binder content b in the kneaded product is set so that the predicted value y of the expansion coefficient of the coal is 1 or more.

The raw material prepared by the kneading machine 15 is introduced into the molding machine 16 and subjected to pressure molding to produce a plurality of molded charcoal. As the molding machine 16, a double roll molding machine can be used. The molding pressure of the molding machine 16 is set so that the predicted value y of the expansion coefficient of the coal is 1 or more. The coal thus produced is once stored in the tank 17. The shape of the charcoal is not particularly limited, and may be a Macek type, for example. The average particle size of the charcoal is, for example, 30 to 100 mm. The average particle diameter here is an arithmetic average value of the particle diameter A ₁ [mm] calculated by the following formula (5) on the assumption that the volume V ₁ [ml] of the coal is a sphere having the same volume.
A ₁ = 2 × ((V ₁ × 3/4 / π) ^1/3 ) × 10 (5)

  The charcoal in the tank 17 produced in the molding step S5 is transferred to the dry distillation section 20. In the carbonization step S6, the coal formed in the molding step is introduced from the top of the carbonization furnace 21 which is a vertical shaft furnace, and the temperature is raised by contacting with the heated gas. The dry distillation furnace 21 has a first tuyere 21a that supplies a first heating gas for heating the coal to the inside of the dry distillation furnace 21, and is lower than the first tuyere 21a and higher than the first heating gas. And a second tuyere 21b for supplying a second heated gas having a temperature.

  The temperature of the first heating gas when the first heating gas is introduced into the dry distillation furnace 21 from the first tuyere 21a, that is, the introduction temperature of the first heating gas is preferably 600 to 700 ° C. The temperature of the second heating gas when the second heating gas is introduced into the dry distillation furnace 21 from the second tuyere 21b, that is, the introduction temperature of the second heating gas is preferably 850 to 1000 ° C., and more Preferably it is 850-950 degreeC. Thus, since the carbonization furnace 21 has a plurality of tuyere for introducing the first heating gas and the second heating gas having different temperatures from each other, the heating rate of the forming coal can be accurately adjusted. Can do.

  The dry distillation furnace 21 has a gas extraction port 21c below the second tuyere 21b. The gas extracted from the gas extraction port 21c by the ejector 25 is integrated with the gas that drives the ejector 25 and becomes the first heating gas. The dry distillation furnace 21 has a cooling gas introduction port 21d for introducing a cooling gas for cooling coke generated by dry distillation, below the gas extraction port 21c. The temperature of the cooling gas introduced from the cooling gas inlet 21d, that is, the introduction temperature of the cooling gas is preferably 20 to 60 ° C. That is, the dry distillation furnace 21 is provided with a first tuyere 21a, a second tuyere 21b, a gas extraction port 21c, and a cooling gas introduction port 21d sequentially from the top to the bottom.

  When the charcoal is introduced from the top of the carbonization furnace 21, the charcoal comes into countercurrent contact with the heated gas rising in the carbonization furnace 21. Thereby, the temperature rise of the coal is started. The heating temperature at the beginning of the introduction of the charcoal can be adjusted by changing the temperature at the top of the dry distillation furnace 21. The temperature at the top of the dry distillation furnace 21 is, for example, 250 to 400 ° C. The coal is heated while descending in the carbonization furnace 21. Then, the maximum temperature is reached in the vicinity of the second tuyere 21 b of the dry distillation furnace 21. This maximum temperature is substantially equal to the introduction temperature of the second heated gas. In this way, the carbonization of the charcoal proceeds to produce the molded coke. The maximum temperature of the coal coal during dry distillation is, for example, 850 to 1000 ° C.

  The formed molded coke moves downward in the carbonization furnace 21, contacts the cooling gas introduced from the cooling gas inlet 21d, and is cooled to about 50 to 150 ° C. The cooled molded coke is taken out from the bottom of the dry distillation furnace 21. In this way, a molded coke having a high strength can be produced continuously.

  The gas discharged from the top of the dry distillation furnace 21 is introduced into a tar recovery facility 22 including a sensible heat recovery device 22a and a gas cooler 22b. The tar recovery facility 22 purifies the gas by removing moisture contained in the gas and light fractions of tar and pitch. The refined gas is reintroduced into the dry distillation furnace 21 by a circulation facility and is circulated for use. The circulation facility is provided with a heat storage furnace 23 and a heat exchanger 24. A part of the purified gas is heated to, for example, 850 to 1000 ° C. in the heat storage furnace 23, and then introduced into the dry distillation furnace 21 from the second tuyere 21 b as the second heating gas. Further, another part of the generated gas is heated to, for example, 500 to 600 ° C. in the heat exchanger 24 and then becomes a driving gas for the ejector 25. This gas is integrated with the gas extracted from the gas extraction port 21c of the dry distillation furnace 21 in the ejector 25 and becomes the first heating gas. This first heated gas is introduced into the dry distillation furnace 21 from the first tuyere 21a.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, it is not indispensable to perform the manufacturing method of the forming charcoal and the forming coke with a continuous forming coke manufacturing facility as shown in FIG. 3, and it may be performed by a batch process.

  The contents of the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Preparation of raw materials]
Raw coal (A coal and B coal) having the properties shown in Table 1 was prepared as coal. The properties shown in Table 1 are values measured according to JIS M 8812: 2006. Moreover, commercially available soft pitch and tar were prepared as a binder.

[Measurement of expansion coefficient of coal]
Pretreatment (preliminary dry distillation) of each raw coal was performed to obtain coal having a volatile content of 5% by mass. In accordance with “9. Expandability test method (dilatometer method)” of JIS M 8801: 2004, a rod-shaped coal molded body was produced, and the expansion coefficient x of the coal simple substance was determined. Specifically, after the pretreatment, the particle size of the coal was reduced to 150 μm or less by pulverization. This coal was molded at a standard molding pressure (d ₀ = 2 ton / cm) and molded into a size of 6 mm in diameter and 60 mm in length to produce a molded body. The molded body was put into a thin tube having an inner diameter of 8 mm, a piston was placed thereon, and a load of 1.47 N was applied. With the load applied, it was heated to 500 ° C. at a rate of temperature increase of 3 ° C./min in an electric furnace. From the displacement of the piston, the expansion coefficient x of the coal simple substance was obtained by the above equation (2). The expansion coefficient x of raw coal that has not been pretreated was also determined in the same manner.

[Derivation of ratio A]
Coal and a binder (soft pitch or tar) were mixed to prepare a plurality of kneaded samples having different binder contents as shown in Tables 2 and 3. This kneaded material sample was molded at a molding pressure d ₀ shown in Table 2 to produce a rod-shaped first charcoal sample having a diameter of 6 mm and a length of 60 mm. The expansion coefficient w ₀ of the first coal sample was determined by the same method as the expansion coefficient x of the coal simple substance. These results are shown in Tables 2 and 3.

Using the results of Tables 2 and 3, single regression analysis was performed using the binder content b as an independent variable and the change w of the expansion coefficient due to the addition of the binder as a dependent variable. At this time, the intercept was set to 0. By this single regression analysis, the following formula (6) is derived for each type of binder, and the slope, that is, the ratio A is obtained.
w = A × b (6)

In formula (6), w represents the amount of change in expansion coefficient depending on the binder content, and b represents the binder content (mass%). Moreover, A shows the ratio [1 / mass%] of the variation | change_quantity of the expansion coefficient of the coal coal with respect to the content rate of a binder. The ratio A obtained by single regression analysis of the results in Table 2 was 0.018 , and the ratio A obtained by single regression analysis of the results in Table 3 was 0.02 . The correlation coefficients of the single regression analysis results in Table 2 and Table 3 were R ² = 0.995 and R ² = 0.996, respectively. This indicates that the coefficient of expansion of the coal can be accurately predicted by the binder content b.

[Derivation of ratio C]
Coal and soft pitch were mixed to prepare a kneaded material sample having a soft pitch content of 8% by mass. As shown the kneaded product samples in Table 4, reference molding pressure d ₀ or from this by molding at a different molding pressures, to produce a second molded charcoal sample bar-shaped having a size of diameter 6 mm, length 60 mm. The expansion coefficient z ₀ of the second molded charcoal sample was determined by the same method as the expansion ratio x of coal. These results are shown in Table 4.

Reference molding pressure of _{d 0} of the molding pressure is 2 ton / cm. Therefore, the difference between the change amount of the expansion coefficient when the molding pressure is 5 ton / cm (z ₀ −x) and the change amount of the expansion coefficient when the molding pressure is 2 ton / cm (z ₀ −x) By dividing by the difference (d−d ₀ = 5-2−3), the ratio C [z / (d−d) of the change amount z of the expansion coefficient to the difference (d−d ₀ ) between the molding pressure and the reference molding pressure. ₀ )]. As a result, the ratio C was 0.025.

As the binder, tar was used instead of the soft pitch to prepare a kneaded material sample having a tar content of 8% by mass. The kneaded product samples were molded under the same conditions as Table 4, to prepare a second molded charcoal sample was determined expansion z _0. From this result, the ratio C was determined to be 0.025, which was the same as when the soft pitch was used.

(Examples 1-9, Comparative Examples 1-3)
Using the above-described coal and binder, a continuous molding coke manufacturing facility as shown in FIG. 3 was prepared. The raw coal (A charcoal, B charcoal) shown in Table 1 was heated to 400 to 650 ° C. using an electric furnace to perform a pretreatment process. The volatile content of the coal after the pretreatment was as shown in Table 1. Using this coal and the binder shown in Table 5, the mixing process, the molding process, and the dry distillation process were performed by the continuous molding coke manufacturing facility in FIG. In the carbonization furnace 21, the coal was heated to 900 ° C. Table 5 shows the binder content in the kneaded product and the molding pressure (linear pressure) by the double roll molding machine.

Table 5 shows the value of linear pressure and the value of surface pressure as the molding pressure. The linear pressure and the surface pressure can be converted into each other, and either index may be used as the molding pressure. The surface pressure described in Table 5 is a value calculated by a calculation formula [0.2 × (linear pressure−2) +1.08].

Table 6 shows the predicted value of the change in expansion rate due to the binder content b in each example and each comparative example, the predicted value of the change in expansion rate due to the molding pressure d, the predicted value and the actual measurement value of the expansion rate of coal. And the drum strength of the molded coke. The amount of change in the expansion coefficient due to the binder content b is a value calculated using the ratio A obtained in [Derivation of the ratio A] described above. The amount of change in the expansion coefficient due to the molding pressure d is a value calculated using the ratio C obtained in [Derivation of ratio C] described above. The reference molding pressure _{d 0} is a 2 ton / cm.

The actual measurement value of the expansion coefficient of the coal is a value measured by the same method as the above-mentioned [Measurement of the expansion coefficient of coal]. From the results shown in Table 6, it is confirmed that by using the binder content b and the difference between the molding pressure and the standard molding pressure (d−d ₀ ) and the ratios A and C, the expansion rate of the coal can be predicted with high accuracy. It was done. And it was confirmed that the molding coke which has high intensity | strength can be manufactured stably by making the expansion coefficient of the coal char | exponent estimated with high precision 1 or more.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the molding coke which can manufacture the molding coke which has high intensity | strength stably, and the manufacturing method of coal char can be provided.

  DESCRIPTION OF SYMBOLS 10 ... Molding charcoal production part, 11 ... Tank, 12 ... Primary grinder, 13 ... Dryer, 14 ... Secondary grinder, 15 ... Kneading machine, 16 ... Molding machine, 17 ... Tank, 20 ... Dry distillation part, 21 ... Carbonization furnace, 21a ... tuyere, 21b ... tuyere, 21c ... gas extraction port, 21d ... cooling gas introduction port, 22 ... tar recovery facility, 22a ... sensible heat recovery device, 22b ... gas cooler, 23 ... thermal storage furnace, 24 ... heat exchanger, 25 ... ejector, 100 ... continuous molding coke manufacturing facility.

Claims (4)

A molding coke production method comprising: a molding step of kneading and molding coal and a binder to produce a molded coal; and a carbonization step of carbonizing the molded coal to obtain a molded coke,
Before the molding step, using the coal and the binder, preparation for predicting the change in the expansion rate of the coal formation due to the binder content and the change in the expansion rate of the coal formation due to molding pressure Has a process,
The preparation step includes
A plurality of kneaded material samples having different binder contents are prepared from the coal and the binder, and the binder is used by using the first molded coal sample obtained by molding the kneaded material sample at a predetermined molding pressure. A first step of obtaining a change amount w of the expansion coefficient accompanying a change in the content rate of the material, and obtaining a ratio A [1 / mass%] of the change amount w with respect to the content rate of the binder;
Using a plurality of second molded coal samples obtained by molding the kneaded material sample containing the coal and the binder at different molding pressures, the change amount z of the expansion coefficient accompanying the change in the molding pressure is obtained. A second step of obtaining a ratio C [cm / ton or cm ² / ton] of the amount of change z with respect to a difference between the molding pressure and the predetermined molding pressure, and predicting an expansion coefficient of the coal The value y is obtained by the following formula (1),
Wherein in the molding step, by molding at a molding pressure of 2~6ton / cm or 1.1~1.9ton / cm ^2, Ri der prediction value y is 1 or more expansion rate based on the prediction result of the preparation process, expansion coefficient to produce the molded coal Ru der 1 above, in the method of manufacturing a molded coke.
y = x + A × b + C × (d-d 0) (1)
[Wherein x represents the expansion rate of the coal molded at the predetermined molding pressure, b represents the binder content (mass%) in the molding step, and d represents the molding pressure ( ton / cm or ton / cm ² ), and d ₀ represents the predetermined molding pressure (ton / cm or ton / cm ² ). d is ² to 6 ton / cm or 1.1 to 1.9 ton / cm ² , and d ₀ is ² to 4 ton / cm or 1.1 to 1.5 ton / cm ² . ] The method for producing molded coke according to claim 1, wherein a volatile content of the coal kneaded with the binder is 20% by mass or less. The method for producing molded coke according to claim 1 or 2, wherein the binder includes at least one selected from the group consisting of coal tar, petroleum pitch, coal pitch, soft pitch, polyvinyl alcohol, petroleum asphalt, and waste oil. A method for producing coal char having a molding step of kneading and molding coal and a binder to produce coal char,
Before the molding step, using the coal and the binder, preparation for predicting the change in the expansion rate of the coal formation due to the binder content and the change in the expansion rate of the coal formation due to molding pressure Has a process,
The preparation step includes
A plurality of kneaded material samples having different binder contents are prepared from the coal and the binder, and the binder is used by using the first molded coal sample obtained by molding the kneaded material sample at a predetermined molding pressure. A first step of obtaining a change amount w of the expansion coefficient accompanying a change in the content rate of the material, and obtaining a ratio A [1 / mass%] of the change amount w with respect to the content rate of the binder;
Using a plurality of second molded coal samples obtained by molding the kneaded material sample containing the coal and the binder at different molding pressures, the change amount z of the expansion coefficient accompanying the change in the molding pressure is obtained. A second step of obtaining a ratio C [cm / ton or cm ² / ton] of the amount of change z with respect to a difference between the molding pressure and the predetermined molding pressure, and predicting an expansion coefficient of the coal The value y is obtained by the following formula (1),
Wherein in the molding step, by molding at a molding pressure of 2~6ton / cm or 1.1~1.9ton / cm ^2, Ri der prediction value y is 1 or more expansion rate based on the prediction result of the preparation process, expansion coefficient to produce the molded coal Ru der 1 above, in the method of manufacturing a molded charcoal.
y = x + A × b + C × (d-d 0) (1)
[Wherein x represents the expansion rate of the coal molded at the predetermined molding pressure, b represents the binder content (mass%) in the molding step, and d represents the molding pressure ( ton / cm or ton / cm ² ), and d ₀ represents the predetermined molding pressure (ton / cm or ton / cm ² ). d is ² to 6 ton / cm or 1.1 to 1.9 ton / cm ² , and d ₀ is ² to 4 ton / cm or 1.1 to 1.5 ton / cm ² . ]

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