JP5064198B2 - Ventilation resistance measuring device for coal softened and molten layer and method for measuring ventilation resistance - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an evaluation test apparatus for coking coal for coke production, and more particularly to an apparatus and a method for measuring the ventilation resistance of a coal softening melt layer used for estimating an expansion pressure generated in coke oven operation. It is.

  The coke oven is configured by alternately arranging a plurality of carbonization chambers and combustion chambers, and the coke oven operation is performed by charging raw coal into each carbonization chamber in a predetermined order, carbonizing the coal for a predetermined time, The obtained coke cake is extruded and pulverized to a predetermined particle size.

  The coal in the carbonization chamber is first heated by heat transfer from the adjacent combustion chamber across the furnace wall to form a coal softened molten layer, and the softened molten layer is carbonized by heat transfer. By gradually shifting to the center of the chamber, the carbonization of coal proceeds. The softened and melted layer of coal has fluidity and is in an expanded state due to internal pressure due to gasification of a part of volatile components and light components in coal.

  When heated further, the generated gas escapes from the softened and melted layer of coal, and the coal resolidifies to form a coke layer. After the resolidification of the coal, the coke layer shrinks until the start of coke extrusion.

  In the carbonization chamber in the coal carbonization process, pressure (hereinafter referred to as expansion pressure) is applied in a direction perpendicular to the furnace wall of the carbonization chamber due to expansion of the coal softening and melting layer. This expansion pressure is transmitted to the furnace wall of the surrounding carbonization chamber via the combustion chamber, causing a problem that the furnace wall of the surrounding carbonization chamber is deformed and the extrudability of coke is deteriorated.

  An increase in the expansion pressure in the carbonization chamber and a corresponding increase in the coke extrusion load cause damage to or loss of the coke oven wall bricks. In the worst case, the coke oven cannot be operated. Therefore, controlling the expansion pressure in the coke oven operation below the allowable limit value is an important issue from the viewpoint of stable coke oven operation and maintaining the integrity of the furnace body.

  In particular, in recent years, the number of aging coke ovens has increased, the strength of the furnace body has decreased, and the allowable limit value of expansion pressure has decreased. Coal charging bulk density rises and the generated expansion pressure during coke oven operation tends to increase. Therefore, management and control of expansion pressure in coke oven operation has become an increasingly important issue in recent years.

  The expansion pressure generated in the coke oven operation is mainly caused by the internal pressure of the gas generated during the softening and melting process of coal, and the magnitude of the expansion pressure is the properties of the raw coal, particle size, water content, preheating temperature, Furthermore, it is considered to be determined by operating conditions such as charging density and carbonization rate (see Non-Patent Document 1, for example).

As a method for evaluating the expansion pressure in the conventional actual furnace operation, (i) In the actual furnace operation, a metal pipe having an inner diameter of several mm provided with a slit at the tip is inserted from the coal charging inlet or the furnace lid to soften the coal. A method for measuring the gas pressure in the molten layer (for example, see Non-Patent Document 2, Patent Documents 1 and 2), or (ii) a large movable wall type dry distillation furnace having a size close to that of an actual furnace (the volume of the carbonization chamber is 0 0.1 to 0.5 m ³ ), and a method for measuring and evaluating the expansion pressure applied to the furnace wall surface during the coal carbonization process (for example, see Non-Patent Document 3 and Patent Document 3).

  However, in the actual coke oven operation, the method of inserting the metal tube into the coal softening and melting layer is as follows: (a) the metal tube cannot be fixed at the intended insertion position; (b) In addition, the softened and melted coal is clogged, and (c) the thickness region of the softened molten layer in which the gas pressure can be measured is limited by the outer diameter of the metal tube. In fact, it is difficult to obtain the measured value of gas pressure, and it is impossible to estimate the expansion pressure with high accuracy.

  In addition, the large movable wall type carbonization furnace can directly measure the expansion pressure generated in the coal carbonization process under each condition, but it has a large internal volume similar to that of an actual coke oven. , The time required for coke discharge after carbonization is about the same as that of an actual coke oven (18 to 24 hours), and the expansion pressure during the coal carbonization process under each condition cannot be measured and evaluated quickly. .

  In addition, a method for measuring and evaluating the expansion pressure in the coal carbonization process using a simple method and apparatus compared to an actual coke oven or a large movable wall type carbonization furnace has also been proposed (for example, Patent Documents 4 and 5, and Non-Patent Documents 4, 5, 6 and 7).

  For example, as a simple expansion pressure measuring device, there is a Nedelmann type bottom surface heating type expansion pressure measuring device (see, for example, Non-Patent Document 6 and Patent Document 4). It is known that there is no correlation with the expansion pressure measured directly in a large movable wall type distillation furnace (for example, see Non-Patent Document 7).

  Moreover, the pressure in the coal softening / melting layer or the pressure and the layer thickness in the coal softening / melting layer is measured with a metal tube for pressure measurement using a simple type carbonization furnace. There is known a method for estimating the expansion resistance by estimating the airflow resistance in the softened and melted layer (for example, see Patent Documents 5 and 6).

  In these apparatuses and methods, an inert gas is circulated into the coal softening / melting layer from the outside, the pressure loss is measured, and based on this, the ventilation resistance is not directly obtained, but a metal tube for pressure measurement is used. Thus, the pressure of the gas generated in the softened and melted coal layer is measured, and the airflow resistance is indirectly estimated from this.

  According to the study by the present inventors, the ventilation resistance estimated based on the pressure measured by this method and apparatus has a large variation, compared with the expansion pressure directly measured by a large movable wall type distillation furnace, It became clear that there was a problem that the difference depending on the operating conditions such as coal type did not appear greatly.

  In addition, since these methods take time to set up a metal tube for pressure measurement, a method that can more easily and quickly measure the airflow resistance of the coal softening and melting layer and evaluate the expansion pressure is expected. .

  On the other hand, the pressure loss ΔP when an arbitrary gas is circulated in the coal softening melt layer from the outside at a predetermined flow rate is measured, and the ventilation resistance is obtained based on this, and the expansion pressure is determined based on this ventilation resistance. Methods and devices for evaluation are also known (see, for example, Non-Patent Documents 7 and 8).

  However, according to the study by the present inventors, in this apparatus, the measured value of the pressure loss ΔP of the coal softening / melting layer caused by the temperature distribution in the cross section perpendicular to the thickness direction of the coal sample varies greatly, and the ventilation with high accuracy is performed. The resistance was difficult to measure, and it was found that the expansion pressure did not show much difference depending on the operating conditions such as coal type compared to the expansion pressure measured directly in the large movable wall type distillation furnace.

  This simple carbonization furnace is used to measure the pressure loss ΔP when an arbitrary gas is circulated from the outside into the coal softening and melting layer at a predetermined flow rate. From this measured value, the ventilation resistance is obtained, and the expansion pressure is evaluated. Compared with a large-sized movable wall type carbonization furnace, the apparatus which can estimate the expansion pressure according to each operation condition in a short time. Therefore, it is desired to develop a simple dry distillation furnace and a measuring method that can measure the ventilation resistance with high accuracy.

JP-A-6-264068 JP-A-7-207271 JP-A-5-255670 JP-A-6-74659 JP-A-5-43880 JP-A-5-180748 C.C.Russell et al., Pro. Blast Furnace Coke Oven and Raw Materials, AIME12 (1935), 197} Latshaw et al. (G.M.Latshaw et al., Ironmaking Conference Proceedings, AIME, 43 (1984), p.373) (JohnTucker and Geoffrey Everitt: British Coal Corporation Cool Research Establishment, AIME 48th Ironmaking Conference 1989, 4.2 ~ 5 Chicago, U.S.A.) Nishioka et al .: Fuel Association, 68.3 (1989) Mabushi et al .: Fuel Association 78th Coke Special Meeting, P3 (1985) Fuel Analysis Test Method, p.105 COKE Quality and Production, R.Loison et al., Butterworths (1989), p.1356 Miura et al .: Coke Circular, Vol. 40 No. 2 (1991), p.103 M.D.Casal et al .: Fuel, 85 (2006), p.281

  When estimating and evaluating the expansion pressure of the carbonization chamber according to the conditions of coke oven operation, the present invention has a measurement time shorter than that of a large movable wall type dry distillation furnace and is equivalent to or larger than that of a large movable wall type dry distillation furnace. An object of the present invention is to provide an apparatus for measuring the airflow resistance of a coal softened molten layer and a method for measuring the same, which can estimate and evaluate the expansion pressure with high accuracy.

This invention solves the said subject, and the summary of the invention is as follows.
(1) In the apparatus for measuring the air resistance of a coal softening / melting layer mainly comprising an apparatus main body, a heating furnace, a thermometer, a pressure gauge, and a mass flow controller, the apparatus main body has a coal sample chamber in the center in the longitudinal direction. A pair of upper and lower mesh plates disposed above and below the coal sample chamber in the outer tube, and a pair of upper and lower mesh plates for fixing the pair of mesh plates by pressing from above and below in the outer tube It is fixed from the outer periphery of the outer tube while sealing the ends of the upper and lower outer tubes and the mesh plate fixing tube through packing, with a gas inlet and gas outlet for circulating gas to the coal sample chamber And a pair of upper and lower caps, the diameter of the coal sample chamber is 13 mm or less, and the pore diameter of the mesh plate is 0.3 mm or less. Apparatus.

  (2) The coal softening melt layer ventilation resistance measuring apparatus according to (1), wherein the height of the coal sample chamber is 13 mm or less.

  (3) Ventilation resistance measurement of coal softening / melting layer according to (1) or (2) above, wherein the temperature difference between the central portion and the outer peripheral portion in the radial direction of the coal sample chamber is within ± 2 ° C. apparatus.

  (4) Using the coal softening melt layer ventilation resistance measuring device according to any one of (1) to (3), a coal sample is charged into a coal sample chamber, and a mass flow controller is used for the coal sample. While circulating the inert gas and heating the coal sample in a heating furnace, measure the temperature and pressure loss of the coal sample layer using a thermometer and pressure gauge, and based on the measured pressure loss at the coal softening and melting temperature A method for determining a ventilation resistance of a coal softened molten layer, wherein the flow rate of an inert gas flowing through the coal sample layer is 25 cc / min or less.

  (5) The coal sample is obtained by measuring the particle size distribution of the coal after pulverizing the coal, and then adjusting the abundance ratio for each particle size classification so that the particle size distribution of the coal after pulverization is obtained. The method for measuring the airflow resistance of the coal softening / melting layer as described in (4) above.

  According to the present invention, in a device for measuring ventilation resistance, it is possible to suppress variation in pressure loss ΔP due to a difference in a molten state according to a temperature distribution in a cross section perpendicular to the thickness direction of a coal sample, as compared with the conventional case. Therefore, when estimating and evaluating the expansion pressure of the carbonization chamber according to the conditions of coke oven operation, based on the pressure loss ΔP and the ventilation resistance required in the future, in a shorter measurement time than a large movable wall type distillation furnace, and The expansion pressure can be estimated and evaluated with high accuracy equal to or better than that of the movable wall type carbonization furnace.

  First, the principle of the method for measuring the airflow resistance of the coal softened molten layer will be described.

  In general, the expansion pressure of the carbonization chamber is caused by the gas pressure in the layer determined by (a) ventilation resistance, (b) gas generation amount, and (c) layer thickness in the coal softening / melting layer. However, in normal coke oven operation, (b) and (c) do not change greatly, so the expansion pressure is considered to be governed by the ventilation resistance of (a). Therefore, if the ventilation resistance of the coal softened molten layer can be measured with high accuracy, it becomes possible to estimate and evaluate the expansion pressure of the carbonization chamber under the conditions at the time of coke oven operation from this measured value.

The airflow resistance of the softened molten layer of coal is defined as the reciprocal of the gas permeability coefficient K (m ² ), and the layer thickness L (m) and gas viscosity of the coal softened molten layer when gas passes through the coal softened molten layer. From μ (Pa · s), gas flow velocity u (m / s), and pressure loss ΔP (Pa), the following equation (1) is obtained.
Ventilation resistance = 1 / K = ΔP / (μ · L · u) (1)

  According to the above equation (1), the airflow resistance is a pressure generated by heating a coal sample layer having a predetermined layer thickness L and circulating a gas having a gas viscosity μ from the outside at a predetermined gas flow rate u. It is obtained by measuring the loss ΔP.

  Assuming that the layer thickness L, the gas flow rate u, and the gas viscosity μ are constant, the ventilation resistance can be handled almost equal to the pressure loss ΔP. Therefore, in the following description, the ventilation resistance is actually measured. It is used in the same meaning as the pressure loss ΔP.

  Conventionally, an apparatus and a measuring method for measuring the airflow resistance of the coal softening / melting layer according to the above principle have been proposed (for example, see Non-Patent Documents 7 and 8).

  However, according to the study by the present inventors, the conventional ventilation resistance measuring device and the measuring method thereof have a large variation in the measured value of the pressure loss ΔP due to the following items (t) to (w): It was found that the expansion pressure does not show much difference depending on the operating conditions such as coal type compared to the expansion pressure measured directly in the large movable wall type distillation furnace.

  (T) During the heating process, the temperature distribution in the direction perpendicular to the thickness of the coal layer is large, and a difference occurs in the molten state of the coal.

  (U) It is difficult to constrain the expanded coal softened molten layer within a predetermined volume, and the bulk density of the coal softened molten layer changes.

  (V) When the coal sample layer thickness is thick, the variation in the gas flow velocity in the cross section perpendicular to the coal layer thickness increases.

  (W) When the gas flow rate is large, the variation in the gas flow velocity in the cross section perpendicular to the coal layer thickness increases.

The present invention is based on the problems of the conventional ventilation resistance measuring device and measuring method for coal softening and melting layer,
(X) making the temperature difference in the cross section perpendicular to the layer thickness of the coal sample as small as possible and making the molten state of the coal resulting therefrom uniform;
(Y) constraining the expanded coal softened molten layer within a predetermined volume, suppressing changes in the bulk density of the coal softened molten layer; and
(Z) maintaining a uniform gas flow rate in a cross section perpendicular to the thickness of the coal softening melt layer;
An apparatus and a method for measuring the airflow resistance of a coal softened and melted layer that realizes the above are provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an embodiment of the apparatus for measuring the airflow resistance of a coal softened / melted layer according to the present invention (hereinafter sometimes referred to as the present apparatus). In addition, (A) shows the whole measuring apparatus, (B) shows the detail of an apparatus main-body part.

  The apparatus according to the present invention mainly includes an apparatus main body 15, a heating furnace 1, a thermometer 16, a pressure gauge 2, and a mass flow controller 3.

  The apparatus main body includes an outer pipe 4 provided with a coal sample chamber 12 in the center in the longitudinal direction, a pair of upper and lower mesh plates 5 disposed above and below the coal sample chamber 12 in the outer pipe 4, and the pair of meshes. While having a pair of upper and lower mesh plate fixing pipes 6 for pressing and fixing the plate 5 from the upper and lower sides in the outer pipe 4, a gas inlet 13a and a gas outlet 13b for circulating gas to the coal sample chamber 12, The upper and lower outer tubes 4 and the mesh plate fixing tube 6 are composed of a pair of upper and lower caps 8 for fixing the outer ends of the outer tube 4 while sealing the end portions of the mesh plate fixing tubes 6 with packings 9.

  As a means for fixing the ends of the outer tube 4 and the mesh plate fixing tube 6 from the outer periphery of the outer tube 4 while sealing them with the packing 9 using a pair of upper and lower caps 8, In addition to forming the female screw 10a, male screws 10b can be formed on the upper and lower outer circumferences of the outer tube 4, and the female screw 10a and the male screw 10b can be screwed together and fixed.

  As a means for pulling out the mesh plate fixing tube 6 from the outer tube 4 after the end of the test for measuring the ventilation resistance, a pulling round bar formed with a female screw 11 on the inner surface of the mesh plate fixing tube 6 and processed with a male screw at the tip. (Not shown) can be attached to the internal thread 11 of the mesh plate fixing tube 6, and the mesh plate fixing tube 6 can be pulled out by using this drawing round bar.

  By this drawing method, even when the outer plate 4 is fixed to the mesh plate fixing tube 6 by tar or the like generated by dry distillation of coal, the mesh plate fixing tube 6 is pulled out and the coal sample 7 in the coal sample chamber 12 is discharged. Becomes easier.

  The heating furnace 1 includes at least the range of the coal sample chamber 12 in the longitudinal direction of the apparatus main body, is disposed so as to surround the outer periphery of the outer tube 4, and includes at least the radial center and outer periphery of the coal sample chamber 12. Control is performed so that the average temperature measured by thermometers such as thermocouples arranged at a plurality of locations becomes the temperature set value.

  The pressure gauge 2 and the mass flow controller 3 are provided in a gas pipe 14 connected to the gas inlet 13a of the apparatus main body. The pressure gauge 2 measures the pressure on the gas inlet 13a side, and the pressure loss ΔP (= P1-P0) when the pressure on the outlet 13b side is the atmospheric pressure P0 is obtained from the pressure measurement value P1. The mass flow controller 3 controls the flow rate of the inert gas supplied from a gas cylinder (not shown) based on the set flow rate.

  The measurement of the airflow resistance of the coal softening melt layer using the apparatus of the present invention is performed as follows.

  First, after temporarily fixing the mesh plate 5 with the mesh plate fixing tube 6 to the lower part of the coal sample chamber 12 in the outer tube 4 in the apparatus main body, the end surfaces of the outer tube 4 and the mesh plate fixing tube 6 are attached to the packing 9. Then, it is fixed using the external thread 10 b on the outer periphery of the outer tube 4 and the internal thread 10 a on the inner periphery of the cap 8.

  Next, the coal is pulverized to a predetermined particle size, a predetermined amount of coal sample is collected from the predetermined particle size coal, and charged into the coal sample chamber 12. Then, after temporarily fixing the mesh plate 5 to the upper part of the coal sample chamber 12 with the mesh plate fixing tube 6, the outer pipe 4 and the end surface of the mesh plate fixing tube 6 are connected to the outer periphery of the outer tube 4 via the packing 9. The male screw 10b and the female screw 10a on the inner periphery of the cap 8 are used for fixing.

  Finally, the cap 8 and the gas pipe 14 of the gas inlet 13a of the outer pipe 4 in which the coal sample 7 is charged in the coal sample chamber 12 are connected by a one-touch joint, and then the apparatus main body is connected to the heating furnace 1 Fix in place.

  An inert gas such as nitrogen gas at a constant flow rate is circulated from a gas cylinder (not shown) to a coal sample 7 in the coal sample chamber 12 using a mass flow controller 3 and up to a set temperature using a heating furnace 1. The temperature is measured by a thermometer such as a thermocouple disposed at a plurality of locations including at least the center and the outer periphery in the radial direction in the coal sample chamber 12.

  In consideration of the influence on the ventilation resistance in the coal sample chamber 12 due to the installation of the thermometer, two apparatus main bodies are arranged in parallel in the heating furnace, the thermometer is provided on one side, and the pressure is provided on the other side. A meter is preferably provided, each measuring the temperature and pressure loss of the coal sample.

  The ventilation resistance (1 / K) at each temperature in the process of heating the coal sample 7 is measured by measuring the pressure on the gas inlet 13a side with the pressure gauge 2 provided on the gas inlet 13a side. From P1, the pressure loss ΔP (= P1−P0) when the pressure on the discharge port 13b side is set to the atmospheric pressure P0 is obtained, and this ΔP is obtained from the above equation (1).

  In general, coal softens and melts at a temperature of approximately 400 to 500 ° C and resolidifies at a temperature of 450 to 550 ° C. Since the softening and melting temperature and resolidification temperature of the coal vary depending on the coal brand and properties, it is preferable to measure the softening and melting temperature of the coal sample in advance by the method defined by JIS.

  As described above, by using the apparatus of the present invention, the ventilation resistance of the coal sample layer (coal softening melt layer) at the softening melting temperature can be measured.

  As described above, during the operation of the actual coke oven, the coal in the carbonization chamber is first heated by the heat transfer from the adjacent combustion chamber across the furnace wall, so that the coal in the vicinity of the furnace wall is heated and the coal softening and melting layer is heated. Is formed, and the softening and melting layer gradually moves to the center of the carbonization chamber by heat transfer, so that the dry distillation of coal proceeds.

  For this reason, in the carbonization chamber in the middle of the carbonization of coal during the actual coke oven operation, the coke layer (resolidified layer), softened molten layer, coal layer (non-distilled) within the range of the furnace width direction from the furnace wall to the center. Layer) coexist. At this time, the softened and melted layer of coal has fluidity and expands due to internal pressure due to gasification of a part of volatile components and light components in the coal.

  In addition, there are a coke layer (re-solidified layer) and a coal layer (non-distilled layer) around the coal softening and melting layer, but the coke layer is in a contracted state due to escape of gas in the layer by heating, Since the coal layer is consolidated by the expansion of the coal softened melt layer, the coal softened melt layer is relaxed from the surroundings.

For this reason, the bulk density BD [kg / m ³ ] of the coal softening and melting layer is equal to the filling bulk density BD ₀ [kg / m ³ ].

  On the other hand, the airflow resistance of the coal softened melt layer measured using the apparatus of the present invention reduces the temperature difference in the radial direction of the coal sample 7 charged in the coal sample chamber 12, and the periphery of the coal sample 7 is a wall. Since it is measured in a restrained state, there is no influence of a decrease in the bulk density of the coal softening and melting layer as in the actual coke oven operation.

  Since the airflow resistance of the coal softening / melting layer is naturally affected by the bulk density, in order to evaluate the airflow resistance of the coal softening / melting layer in actual coke oven operation, the coal measured using the apparatus of the present invention is used. It is necessary to correct the ventilation resistance of the softened molten layer in relation to the density (BD) of the coal softened molten layer in the actual coke oven.

  A method for estimating the airflow resistance of the coal softening / melting layer in the actual coke oven from the airflow resistance of the coal softening / melting layer measured by the measuring apparatus of the present invention will be described below.

The bulk density BD [kg / m ³ ] of the coal softening and melting layer in the actual coke oven is the filling bulk density BD ₀ [kg / m ³ ] when charging the coal, the degree of contraction (volume change) of the coke layer, and the coal Of these, the density of the coal bed is not significantly different under the condition of the bulk density of coal in normal coke oven operation. It is determined by the density (BD ₀ ) and the degree of shrinkage (volume change) of the coke layer.

  The degree of shrinkage (volume change) of the coke layer can be determined, for example, by measuring the coke shrinkage at a temperature equal to or higher than the coal resolidification temperature in the following coal dry distillation test.

The relationship between the temperature above the resolidification temperature of coal and the coke shrinkage ratio is, for example, that pulverized coal is filled in a tubular container, and this coal is heated to a furnace temperature T (° C) that is equal to or higher than the resolidification temperature T _R (° C). When heated, the coal length L _TR at the resolidification temperature T _R (° C.) and the coal length at the temperature T ₁ (° C.) within the range of the re-solidification temperature T _R and the furnace temperature T or less. The length L _T1 is measured, and from this, the coke shrinkage ratio R _T1 (%) at a temperature T ₁ (° C.) equal to or higher than the resolidification temperature can be obtained by the following equation (2).
R _T1 (%) = (L _TR −L _T1 ) / L _TR × 100 (2)

  The shrinkage rate of blended coal in which multiple brands of coal are blended at a prescribed blending ratio can be directly measured by the above method, but the coke shrinkage rate of each brand of coal is measured, It can be obtained by calculating the load average considering the blending ratio of coal.

The bulk density BD [kg / m ³ ] of the coal softening melt layer in the actual coke oven is the filling bulk density BD ₀ [kg / m ³ ] at the time of charging coal blend I and the blending measured as described above. can be obtained from coke shrinkage C _I charcoal I by the following equation (3).
BD = k · BD ₀ · (100 / C _I ) (3)

  Note that k is a constant selected from the range of 0.05 to 0.15 depending on the size of the coke oven and heating conditions. In the embodiment of the present invention, k = 0.1 is used.

  Further, as a simpler method than the method for measuring the shrinkage rate of coke, VM in coal can be measured by a method defined in JIS M8801, and the coke shrinkage rate can be estimated from the VM in coal.

  The coke shrinkage is correlated with the VM (volatile component amount) in the coal, and the higher the VM in the coal, the greater the coke shrinkage.

Therefore, the volatile _matter VM _Ii [%] and the coke shrinkage C _Ii [%] of two or more different blended coals Ii are measured in advance, and the volatile _matter VM _Ii [ %] And the coke shrinkage C _Ii [%], the coke shrinkage can be estimated from the VM measurement value in coal by the following equation (4).
C _I = L ₁ · VM _I + L ₂ (4)

In this embodiment, a linear function obtained from two types of blended coal is used. However, the relational expression between the volatile matter VM _Ii [%] and the coke shrinkage C _Ii [%] of the blended coal Ii is not limited to this. It is good also as a quadratic or cubic function which becomes a monotonously increasing function using three or more kinds of blended charcoal.

From the above, the bulk density BD [kg / m ³ ] of the coal softening and melting layer in the actual coke oven is equal to the filling bulk density BD ₀ [kg / m ³ ] at the time of charging the coal and the coke shrinkage [%] or in the coal The VM [%] can be obtained.

Therefore, when evaluating the air flow resistance value of the coal softening / melting layer under the condition of filling bulk density BD ₀ [kg / m ³ ] at the time of charging coal in an actual coke oven, the packing bulk density at charging of the coal sample is The coal sample was adjusted so as to have the bulk density BD of the coal softened and melted layer obtained by the above formula (3), the pressure loss ΔP [kPa] was measured by the measuring device of the present invention, and the airflow resistance value 1 / It is necessary to find K.

  The ventilation resistance value is obtained from the pressure loss ΔP measured by the measuring apparatus of the present invention by the above equation (1). In the above equation (1), it is assumed that the layer thickness L, the gas flow rate u, and the gas viscosity μ are constant. Then, the ventilation resistance can be handled almost equal to the pressure loss ΔP.

Therefore, the evaluation of the expansion pressure of the coal softening melt layer is performed, for example, by using a relative value P [−] obtained by dividing the pressure loss ΔP [kPa] measured by the measuring apparatus of the present invention by the reference pressure P ₀ [kPa] as an expansion pressure. It can be used as an index.

  The coal softening melt layer ventilation resistance measuring device of the present invention has a coal sample chamber 12 with a diameter of 13 mm or less and a mesh plate 5 with a hole diameter of 0.3 mm or less in the device body, and preferably the height of the coal sample chamber 12 is It is characterized in that it is 13 mm or less.

  With this configuration, the temperature difference from the central portion in the radial direction of the coal sample layer in the coal sample chamber 12 to the outer peripheral portion can be reduced to ± 2 ° C. or less, and the molten state in a cross section perpendicular to the layer thickness of the coal sample layer And variations in pressure loss ΔP due to this difference can be suppressed.

  Below, the diameter and height of the coal sample chamber 12 which are the characteristics of the apparatus and method of the present invention, and further the reasons for limiting the pore diameter of the mesh plate 5, the gas flow rate, and the sample particle size distribution will be described.

(Coal sample chamber diameter: 13 mm or less)
According to the study by the present inventors, for example, the size of the coal sample chamber in the conventional apparatus main body described in Non-Patent Documents 7 and 8 is about 20 mm in diameter and about 10 mm in height, as shown in Table 1. The temperature difference in the radial direction of the coal sample was confirmed to be as large as about 8 to 10 ° C.

  When a large temperature difference occurs in the radial direction of the coal sample layer, the difference in the melting state at each part becomes large, and the resistance to ventilation is smaller than that of the softened and melted part. Therefore, it is expected that the ventilation resistance is apparently measured to be lower than the true value (measured value when the temperature distribution is small).

  The present inventors consider that the main cause of the variation in the airflow resistance of the coal softened and melted layer measured using a conventional measuring apparatus is due to the temperature difference that occurs in the radial direction of the coal sample layer, and the coal sample of the apparatus main body. The relationship between the chamber radius and the temperature difference in the radial direction of the coal sample layer was investigated.

  In FIG. 2, the diameter of the coal sample chamber and the coal sample layer in the coal sample chamber when the temperature of the coal softened melt layer is measured using an apparatus main body having a constant diameter of 10 mm and a diameter different from that of the coal sample chamber. The relationship between the temperature difference between the central portion and the outer peripheral portion when the temperature in the central portion in the radial direction reaches 450 ° C. is shown.

  2 that the temperature difference in the radial direction of the coal sample layer can be reduced to 2 ° C. or less by setting the diameter of the coal sample chamber 12 to 13 mm or less.

  Based on the above knowledge, in the present invention, the temperature difference from the central portion in the radial direction of the coal sample layer to the outer peripheral portion is reduced to ± 2 ° C. or less, and the difference in the molten state in the cross section perpendicular to the layer thickness of the coal sample layer. In order to suppress variations in pressure loss ΔP due to the above, the diameter of the coal sample chamber 12 in the outer tube 4 in the apparatus main body is set to 13 mm or less.

(Pore diameter of mesh plate: 0.3 mm or less)
Table 2 shows the variation in mesh plate hole diameter and pressure loss ΔP when the gas flow rate is constant at 10 cc / min and the pressure loss ΔP of the coal softening / melting layer is measured using an apparatus body with different mesh plate hole diameters. Shows the relationship. The variation of the pressure loss ΔP is represented by the relative standard deviation, that is, the standard deviation value of the pressure loss ΔP with respect to the average value of the pressure loss ΔP.

  From Table 2, it can be seen that the dispersion of the pressure loss ΔP can be reduced to 0.30 in terms of relative standard deviation by setting the mesh plate to have a hole diameter of 0.30 mm or less.

  According to the above knowledge, when the hole diameter of the mesh plate 5 is increased, the coal sample 7 charged in the coal sample chamber 12 is softened and melted, and when expanded, the soft and molten coal flows out from the holes of the mesh plate 5. In addition, since the air flow resistance is apparently lower than the true value (measured value when the temperature distribution is small), the mesh plate 5 has a pore diameter of 0. 3 mm or less.

  In addition, the lower limit of the hole diameter of the mesh plate 5 is not particularly limited, and is set to be equal to or larger than the hole diameter that does not resist the ventilation of the circulating gas as in the mesh plate used in the conventional apparatus. It is.

(Coal sample chamber height: 13 mm or less)
Table 3 shows the height of the coal sample chamber and the variation in the pressure loss ΔP when the pressure loss ΔP of the coal softening / melting layer is measured using an apparatus body having a constant diameter of 10 mm and a different height. The relationship is shown. The variation of the pressure loss ΔP is represented by the relative standard deviation, that is, the standard deviation value of the pressure loss ΔP with respect to the average value of the pressure loss ΔP.

  From Table 3, it can be seen that the variation of the pressure loss ΔP can be reduced to 0.3 in terms of relative standard deviation by setting the height of the coal sample chamber to 13 mm or less.

  According to the above knowledge, when the height of the coal sample chamber 12 in the outer pipe 4 is increased, the variation in the air flow resistance of the coal softened and melted layer due to the difference in the molten state tends to become remarkable. Since the upper ventilation resistance is measured lower than the true value (measured value when the temperature distribution is small), in the present invention, the height of the coal sample chamber 12 in the outer pipe 4 is preferably 13 mm or less.

(Gas flow rate: 25cc / min or less)
Table 4 shows the difference between the gas flow rate and the variation in the pressure loss ΔP when the pressure loss ΔP of the coal softening / melting layer is measured by changing the gas flow rate using an apparatus body having a mesh plate hole diameter of 0.15 mm. Show the relationship. The variation of the pressure loss ΔP is represented by the relative standard deviation, that is, the standard deviation value of the pressure loss ΔP with respect to the average value of the pressure loss ΔP.

  From Table 4, it can be seen that by setting the gas flow rate to 25 cc / min or less, the variation in pressure loss ΔP can be reduced to 0.3 in terms of relative standard deviation. This is because the apparatus of the present invention has a smaller diameter and height of the coal sample chamber 12 than in the prior art, so if the gas flow rate is greater than 25 cc / min, the coal softening / melting layer will be greatly disturbed, and air will blow through at the weak part. This is thought to be easier to do.

  Based on the above knowledge, in this invention, in order to suppress the dispersion | variation in the ventilation resistance of a coal softening melt layer, it is preferable that a gas flow rate shall be 25 cc / min or less.

(Particle size distribution of coal sample)
In the apparatus of the present invention, the diameter and height of the coal sample chamber are small, and the amount of coal sample charged is also small, so depending on how to collect a predetermined amount of coal sample after pulverizing coal to a predetermined particle size, It was found that the particle size of the coal sample is different from the particle size at the time of pulverization, and this causes a variation in measured values of the airflow resistance of the coal softened and melted layer.

  In Table 5, when coal is pulverized to a particle size of 3% below 3 mm, a predetermined amount is collected as it is (Condition 1), 3 to 1 mm in coal of 100% particle size below 3 mm, 1 When a predetermined amount of coal sample is taken so as to maintain the existence ratio of each particle size division of 0.6 mm, 0.6 to 0.3 mm, and 0.3 mm or less (condition 2), The results of measuring the ventilation resistance and determining the variation of the measured values are shown. The variation of the pressure loss ΔP is represented by the relative standard deviation, that is, the standard deviation value of the pressure loss ΔP with respect to the average value of the pressure loss ΔP.

  The coal sample of condition 2 is a 3-1 mm, 1-0.6 mm, and 1 mm, 0.6 mm, and 0.3 mm sieve meshes of 100% granularity of 3 mm or less. Sieve into each particle size division of 0.6-0.3mm and -0.3mm, measure the existence ratio (particle size distribution) of each particle size division, and for each particle size division so that it becomes a predetermined charging amount In addition, it is produced by collecting coal in that proportion.

  The gas flow rate was 10 cc / min, and the mesh plate hole diameter was 0.15 mm.

  From Table 5, after pulverizing coal to a predetermined particle size, by taking a predetermined amount of coal sample so as to maintain the proportion of each particle size classification, the variation in test 2 is reduced, and eventually the variation is reduced For this purpose, it is understood that it is more preferable to combine the samples for each particle size division so that the target particle size distribution is obtained after pulverizing the coal sample into a predetermined particle size division.

  Therefore, when measuring the airflow resistance of the coal softened melt layer using the apparatus of the present invention, after pulverizing the coal sample into a predetermined particle size classification, each particle size classification is set so that the target particle size distribution is obtained. More preferably, each sample is combined.

According to the apparatus for measuring the ventilation resistance of the softened coal layer of the present invention, the expansion pressure index (relative value P obtained by dividing the pressure loss ΔP by the reference pressure P ₀ ) from the measured values of the pressure loss ΔP and the ventilation resistance is set to 0. Since the measurement can be performed in about 5 to 2 hours, the expansion pressure can be evaluated more rapidly than in the case where the expansion pressure is directly measured in a large movable wall type distillation furnace.

  Therefore, in the operation of the actual coke oven, the coal before blending or the coal after blending is sampled, and the pressure loss ΔP and the ventilation resistance of the coal softened molten layer are measured by the apparatus of the present invention to obtain the expansion pressure index. Thus, an operation for managing the coke extrusion load to be equal to or less than the allowable limit value based on the expansion pressure index becomes possible.

  Specifically, the relationship between the expansion pressure index obtained by the apparatus of the present invention and the coke extrusion load in the actual coke oven is determined in advance. For example, when the expansion pressure index is high, (a) coal Coke extrusion based on the expansion pressure index by means such as (b) reducing the blending ratio of coal with a high expansion pressure, (c) increasing the blending ratio of coal having an expansion pressure suppressing effect, etc. The coal pulverization conditions, blending conditions, charging conditions, and dry distillation conditions are adjusted so that the load is less than the allowable limit value.

  Hereinafter, the effects of the present invention will be demonstrated using examples, but the conditions of the examples are one example of conditions adopted for confirming the feasibility and effects of the present invention. It is not limited to the example conditions. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

Example 1
Table 6 shows the results of measuring the expansion pressure index P by measuring the pressure loss ΔP of the coal softening melt layer using the apparatus of the present invention using several types of blended coal (blended coal 1 to blended coal 5) as examples of the invention. Indicates. The expansion pressure index P [−] is a relative value obtained by dividing the pressure loss measurement value ΔP [kPa] by the reference pressure P ₀ [kPa].

  Further, as a comparative example, using the conventional apparatus and measurement method described in Non-Patent Document 9 in which the radius of the coal sample chamber and the hole diameter of the mesh plate are out of the specified range of the present invention, ΔP is similarly calculated from the pressure loss. The expansion pressure index P was measured and compared with the inventive examples.

  In addition, the measurement accuracy of the expansion pressure index P was evaluated by obtaining a correlation coefficient with the expansion pressure directly measured using a large movable wall-type dry distillation furnace.

  From Table 6, the expansion pressure index P of Invention Examples 1 to 3 obtained by using the device of the present invention in which the radius of the coal sample chamber and the pore size of the mesh plate satisfied the specified range of the present invention are all in the coal sample chamber. Compared with the expansion pressure index P of Comparative Examples 1 and 2 in which the radius of the plate and the hole diameter of the mesh plate deviated from the specified range of the present invention, the correlation was very high with the expansion pressure directly measured using a large movable wall type distillation furnace. It can be seen that the estimation accuracy of the expansion pressure is high (measurement variation is small).

  3 (B) and Table 7, in the measurement of the pressure loss ΔP in the measurement of Example 1 of the present invention, the central temperature in the radial direction of the coal sample chamber, the outer peripheral temperature, the average temperature thereof, the central portion and the outer peripheral portion Temperature difference, temperature difference between average temperature and set temperature is shown. From FIG. 3 and Table 7, it can be seen that the difference between the temperature in the center of the coal sample chamber in the radial direction and the temperature at the outer periphery is as small as ± 2 ° C. or less. FIG. 3A shows a temperature measurement position in the coal sample chamber.

  FIG. 4 shows the relationship between the average temperature of the coal sample and the pressure measured on the gas inlet side in the measurements of Invention Example 1 and Comparative Example 1. Since the pressure loss ΔP is obtained based on the pressure measurement value on the gas inlet side when the pressure on the gas discharge side is atmospheric pressure, the temperature dependence of the pressure on the gas inlet side is the temperature of the pressure loss ΔP. Can be evaluated in response to dependencies.

  From FIG. 4, the pressure on the gas inlet side of Invention Example 1 is about 450 ° C. corresponding to the softening melting temperature when the temperature of the coal sample is about 400 ° C. or higher, and the maximum pressure value (0. 12 MPa). On the other hand, the pressure on the gas inlet side of Comparative Example 1 starts to rise from the low temperature side as compared with Invention Example 1, and it can be seen that the maximum value of the pressure is considerably lower than that of Invention Example 1.

  From the comparison between the two, Invention Example 1 can improve the measurement accuracy of the pressure loss ΔP as compared with Comparative Example 1, and has a high reproducibility of the airflow resistance in the coal softening and melting layer of the softening and melting temperature: about 450 ° C. It can be measured.

(Example 2)
In FIG. 5, in the actual furnace operation for 25 days, in period 1 (1 to 12 days), normal operation is performed, and from the period 2 (after 13 days), the coal softening and melting is performed with the measuring apparatus and measurement conditions of Invention Example 1. The pressure loss ΔP of the layer is measured, the expansion pressure index P is obtained, and the coal pulverization conditions, the blending conditions, and the operating conditions are adjusted based on the expansion pressure index P. The transition of relative extrusion load is shown.

  The relative extrusion load means the ratio of the extrusion load current measurement to the control reference value of the extrusion current value of the coke extruder.

  From FIG. 5, in period 1, the relative extrusion load sometimes exceeds 1 (exceeds the control standard value), and the variation is large, but in period 2 to which the present invention is applied, the relative extrusion load is 1 or less ( It is maintained below the control standard value), and the variation of the expansion pressure index is also reduced.

  For example, the expansion pressure index P on the 13th day of period 1 was 9.4, the relative extrusion load was 1.04, and the coke extrusion load exceeded the control standard value. For this reason, the coal blending conditions are changed without changing the coal pulverization particle size and coke oven operating conditions (furnace temperature and coal bulk density) so that the expansion pressure index P is 8, and the expansion pressure in the blended coal is high. When the blending ratio of coal was reduced, on the 14th day, the relative extrusion load was reduced to 0.9 (the expansion pressure index P at this time was 8.6).

  Furthermore, when the blending of coal was changed and the blending ratio of coal having the effect of suppressing the expansion pressure in the blended coal was increased, on the 15th day, the relative extrusion load was 0.86 (the expansion pressure index P at this time was 7.9).

  From the results shown in FIG. 5, by applying the apparatus and method for measuring the airflow resistance of the coal softened melt layer of the present invention to the operation of the coke oven, the expansion pressure of the blended coal in the carbonization chamber is suppressed, and the extrusion during coke extrusion is performed. It can be seen that the load can be controlled below the control value, and it is possible to realize the coke oven life extension with stable coke oven operation without coke extrusion trouble.

  As described above, according to the present invention, it is possible to stably extrude coke by suppressing the expansion pressure, and it is possible to improve the production efficiency of the coke oven by avoiding the decrease in production due to the extrusion trouble. The coke oven furnace wall damage caused by the extrusion trouble can be avoided and the furnace life of the coke oven can be extended.

  Therefore, the present invention has great applicability in the coke manufacturing industry.

It is a block diagram of the ventilation resistance measuring apparatus of the coal softening melt layer of this invention, (A) shows the whole measuring apparatus, (B) shows the detail of an apparatus main-body part. It is a figure which shows the relationship between the diameter of the coal sample chamber in this invention main body, and the temperature difference of the radial direction center part and outer peripheral part of the coal sample layer in a coal sample chamber. It is a temperature curve of the radial direction center part temperature of a coal sample chamber in invention example 1, peripheral part temperature, average temperature, and preset temperature, (A) shows a temperature measurement position and (B) shows a temperature curve. It is a figure which shows the relationship between the average temperature of the coal sample in the invention example 1 and the comparative example 1, and the pressure measured by the gas inlet side. It is a figure which shows transition of the relative extrusion load at the time of coke extrusion before and behind applying this invention to a real coke oven operation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Pressure gauge 3 Mass flow controller 4 Outer pipe 5 Mesh board 6 Mesh board fixed pipe 7 Coal sample 8 Cap 9 Packing 10a Female screw 10b Male screw 11 Mesh board fixed pipe inner surface female screw 12 Coal sample chamber 13a Gas inlet 13b Gas outlet 14 Gas piping 15 Device body 16 Thermometer (thermocouple)

Claims (5)

  In the apparatus for measuring aeration resistance of a coal softening / melting layer mainly including an apparatus main body, a heating furnace, a thermometer, a pressure gauge, and a mass flow controller, the apparatus main body is provided with a coal sample chamber in the center in the longitudinal direction. An outer tube, a pair of upper and lower mesh plates disposed above and below the coal sample chamber in the outer tube, and a pair of upper and lower mesh plate fixing tubes for pressing and fixing the pair of mesh plates from above and below in the outer tube; A gas inlet and a gas outlet for distributing gas to the coal sample chamber are provided, and the ends of the upper and lower outer pipes and mesh plate fixing pipes are sealed from the outer pipe while being sealed through packing. An apparatus for measuring the air resistance of a coal softened melt layer, comprising a pair of upper and lower caps, wherein the coal sample chamber has a diameter of 13 mm or less, and the mesh plate has a hole diameter of 0.3 mm or less.   The apparatus for measuring a ventilation resistance of a coal softening / melting layer according to claim 1, wherein the height of the coal sample chamber is 13 mm or less.   The apparatus for measuring the air resistance of a coal softened / melted layer according to claim 1 or 2, wherein a temperature difference between a central portion in the radial direction of the coal sample chamber and an outer peripheral portion is within ± 2 ° C.   A coal sample is charged into a coal sample chamber using the apparatus for measuring a gas flow resistance of a coal softened and melted layer according to any one of claims 1 to 3, and an inert gas is circulated through the coal sample using a mass flow controller. At the same time, while heating the coal sample in the heating furnace, measure the temperature and pressure loss of the coal sample layer using a thermometer and pressure gauge, and based on the measured value of the pressure loss at the coal softening and melting temperature, A method for determining a ventilation resistance, wherein the flow rate of an inert gas flowing through the coal sample layer is 25 cc / min or less.   The coal sample is obtained by pulverizing coal, measuring the particle size distribution of the coal, and then adjusting the abundance ratio for each particle size classification so as to be the particle size distribution of the coal after pulverization. The method for measuring the airflow resistance of the coal softening / melting layer according to claim 4.

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