JP3100722B2 - Method and apparatus for measuring gas permeability coefficient of coal seam in softened and molten state - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for measuring a gas permeability coefficient of a coal layer in a softened and molten state in a coal carbonization process, and a method for measuring a gas permeability coefficient using the jig.

[0002]

2. Description of the Related Art In the process of producing coke from coal in a coking chamber of a coke oven, the coal expands and exerts a pressure (expansion pressure) on the furnace wall of the coke oven. If this expansion pressure is high, the furnace wall of the coke oven may be damaged, and management of the expansion pressure is an important issue in furnace body management. In Europe and the United States, expansion pressure was regarded as an important control item in the operation of coke ovens from an early stage, and interest in expansion pressure was high.However, in Japan, Australian coal and Canadian coal, which have low expansion pressure, were used in large quantities. No management and control was required. However, in the future, the expansion pressure is said to be high, and the degree of coalification is high (low volatile matter)
As the proportion of coal tends to increase, the furnace is aging and the furnace body is damaged, and attempts have been made to extend the life of the furnace, and the need for expansion pressure control has been increased.

It is known that the cause of the expansion pressure is the gas pressure in the coal layer in the softened and molten state. Attempts have been made to measure the gas pressure in the coal layer in the softened and molten state in actual furnaces and test furnaces. Many researchers have attempted to elucidate the mechanism of expansion pressure generation. It is considered that the gas pressure in the softened and molten layer is determined by the gas permeability coefficient of the layer, the amount of gas generated in the layer, and the thickness of the layer, and attempts have been made to measure the gas permeability coefficient of the coal layer in the softened and molten state. I have. As a method of measuring the gas permeability coefficient, a method of forcibly circulating an inert gas from the outside of a coal layer in a softened and molten state and estimating from a pressure loss before and after the layer is generally used. In the case of a bed, there are few examples of successful measurement of the gas permeation coefficient because a steady gas flow cannot be obtained or the expansion constraint of the coal bed in the softened and molten state changes depending on the gas passed through. .

[0004]

SUMMARY OF THE INVENTION The present invention provides a jig for measuring a gas permeability coefficient of a coal layer in a softened and molten state in a coal carbonization process, and a method for measuring a gas permeability coefficient using the jig. The purpose is to:

[0005]

According to the present invention, there are provided: (1) a predetermined thin tube having a through hole having a diameter of 2 to 4 mm at several positions different in the height direction and having an outer diameter of 2 to 4 mm from the through hole; After inserting a metal tube with an inner diameter of 1 to 3 mm and sealing the contact portion between the metal tube and the through-hole, a predetermined amount of coal sample crushed to a predetermined particle size is kept in powder at a predetermined charging density into a thin tube. Charged, put a piston of a predetermined load, heat it at a predetermined heating rate, measure the pressure of the gas generated in the heating process in the coal seam, measure the vertical displacement of the piston accompanying heating, and , The gas generation rate of the coal sample was measured using a thermobalance, the gas pressure distribution, the softened molten state
Jig and method for measuring the gas permeability coefficient of a coal bed in a softened and molten state, wherein the gas permeability coefficient is obtained from the layer thickness , gas density, gas viscosity, and gas generation rate per unit volume of the coal bed. 2) A metal tube is inserted through a through-hole into a bottomed thin tube having a plurality of through-holes at different positions in the height direction to seal a contact portion between the metal tube and the through-hole. Has a through-hole, a bottomed thin tube provided with a thermocouple, and a piston mounted on a sample, respectively. The gas permeation of a coal bed in a softened and molten state comprising a heating furnace equipped with the two thin tubes is provided. It is a coefficient measuring jig. Hereinafter, the present invention will be described in detail.

[0006]

The gas pressure in the coal bed in the softened and molten state is determined by the gas permeability coefficient of the bed, the amount of gas generated in the bed, and the layer thickness. If the gas pressure, gas generation amount and layer thickness in the coal seam are measured, the inert gas is forcibly circulated from outside and the pressure loss is not measured. It was considered that the gas permeability coefficient in the coal seam could be estimated.

[0007] Therefore, the present inventors have established the JIS rules (JIS-
M-8801) was used to improve the dilatometer used in the coal swellability test method, and the gas pressure in the coal bed in a softened and molten state was measured at several points in the height direction. The gas pressure distribution was described by the following equation. I found something. P = AB-X ² Here, P is the gas pressure in the softened molten layer, X is the position in the height direction with reference to the bottom surface (0), and A and B are constants.

The inventors have derived an equation showing the pressure distribution in the height direction from the one-dimensional gas flow equation and the mass balance equation. Here, gas flow in the radial direction of the tube was ignored, and the gas permeability coefficient in the softened molten layer was assumed to be constant regardless of the location. U = (K / μ) · (dP / dX ) V = ρ · (du / dX) ··· P = (μ · V) · (L ² −X ² ) / (2 · K · ρ) ··· u: flow rate [m / s] K: gas permeability coefficient [m ² ] μ:
Gas viscosity [Pa · s] P: Gas pressure in the softened molten layer X: Height [m] ρ: Gas density [kg / m ³ ] V: Gas generation rate per unit volume [kg / m ³ / s]
L: Layer thickness [m] The form of the equation is the same as that of the equation. Therefore, the gas pressure distribution in the height direction of the dilatometer follows the equation, and the gas pressure distribution, gas viscosity, and unit volume in the height direction of the dilatometer It can be seen that the gas permeation coefficient can be estimated by the equation from the hit gas generation rate, the layer thickness and the gas density. The present invention has been completed based on these findings.

The gas permeability coefficient measuring method used in the present invention will be described below. In the present invention, JIS rules (J
IS-M-8801) The thin tubes 1 and 2 of the dilatometer used in the coal swelling test method of IS-M-8801 are prepared.
A plurality of through holes 3 having a diameter of 2 to 4 mm for allowing the outside and inside to pass through are formed at several different positions in the height direction. This through hole 3
In order to measure the pressure in the coal seam by inserting the metal tube 4 into the, the through hole 3 needs to have a structure that can fix the position of the metal tube 4 and that prevents gas and coal from leaking from the insertion portion. A metal tube 4 having an outer diameter of 2 to 4 mm and an inner diameter of 1 to 3 mm is positioned in the through hole 3 so that one end of the metal tube faces the center of the tube, and the other end is connected to a pressure measuring device 5. After sealing and fixing the connection between the metal tube 4 and the thin tube 1, a coal sample 6 crushed to a predetermined particle size is charged into the thin tube 1 from the upper portion of the tube as a powder at a predetermined charging density. The thin tube 1 is mounted in a heating furnace 7 of a dilatometer.

The heating furnace 7 of the dilatometer has a thin tube 1,
2 can be installed, one of which is provided with a thin tube 1 for measuring gas pressure, and the other of which is provided with a thin tube 2 for measuring the temperature in the coal seam, as described later. Piston loads 8 and 9 are applied to the upper part of the coal seam in the same manner as in the ordinary dilatometer method to measure the vertical displacement of the piston during heating. The piston load is 150 g in a normal dilatometer method,
Here, the magnitude of the piston load determines the magnitude of the degree of restraint of expansion of the softened molten coal, so that if pistons having different weights are prepared, they can be arbitrarily selected according to desired measurement conditions. Thus, the coal sample 6 in the thin tubes 1 and 2
Is heated at a predetermined heating rate, and a time-dependent change in gas pressure in the softened molten coal layer and a time-dependent change in displacement of the pistons 8 and 9 are measured.

In order to measure the temperature in the coal seam, the same coal sample is placed in a dilatometer thin tube 2 having no through hole.
The same amount and the same charge density are charged, and a thermocouple 11
After applying a piston load of the same weight, the thin tube 2 is mounted in a heating furnace 7 of a dilatometer, and the time-dependent change in temperature is measured. Further, with respect to the same coal sample, a change with time of the gas generation rate is measured at the same heating rate by using a thermobalance (not shown).

[0012] Thus, the gas pressure distribution, softening molten
The thickness and gas generation rate of the coal bed in the state, plot the height position (bottom 0) on the horizontal axis and the gas pressure on the vertical axis at an arbitrary temperature and curve using the equation. The gas permeability coefficient of the coal seam in the softened and molten state is determined by the fitting method. Thereby, the gas permeation coefficient in the coal softening molten layer at an arbitrary temperature can be estimated.

[0013]

【Example】

Example 1 Coal A (particle size-1 mm, 100%) and a piston load of 0
g, heating rate 3 ° C / min, charge density 0.95g / cm
^{3. The} gas permeability coefficient was measured under the conditions of coal weight (10 g, 8 g). The properties of the coal used are shown in Table 1, and the results of measuring the gas pressure distribution in the height direction of the dilatometer are shown in FIG. The pressure distribution in the height direction agrees well with the equation, and the value of the gas permeability coefficient is 4. when the coal weight is 10 g and 8 g, respectively.
2 × 10 ^-13 [m ² ] and 3.1 × 10 ^-13 [m ² ].
This value is in good agreement with existing literature values.

[0014]

[Table 1]

Example 2 Coal A (particle size-1 mm, 100%) was used at a heating rate of 3 ° C /
Table 2 shows the measurement results of the gas permeation coefficient in the softened molten layer measured under the conditions of min, charge density of 0.95 g / cm ³ , charge amount of 5 g, piston load of 0 g, 290 g, and 500 g. This indicates that the larger the piston load, the larger the gas permeability coefficient. This is considered to be due to the fact that when a load is applied, the cohesiveness of the coal is promoted, the coal particles adhere well to each other, and the gas permeability coefficient in the softened molten coal layer decreases, which is consistent with the conventional knowledge.

[0016]

[Table 2]

[0017]

According to the present invention, it has been conventionally difficult to measure the gas permeability coefficient of a coal layer in a softened and molten state. However, as described in detail above, according to the present invention, it has been conventionally used for a coal expansion test. It was possible to estimate the gas permeation coefficient in the softened molten layer by measuring the gas pressure distribution in the height direction of the softened molten coal layer simply by performing simple work on the thin tube of the dilatometer.
According to the present invention, it becomes possible to measure the gas permeability coefficient in the softened and molten state of various types of coal, opening the way to a method for estimating the expansion pressure, and establishing a method for estimating the expansion pressure based on the present invention. The present invention can make a great economic contribution in terms of coke oven operation with reduced damage and prolonged oven life.

[Brief description of the drawings]

FIG. 1 is a diagram showing a gas pressure distribution in a softened molten layer in a dilatometer height direction;

FIG. 2 is a side view of a measuring jig (a thin tube) according to an embodiment of the present invention;

FIG. 3 is a view showing mounting of a measuring jig in the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Narrow tube with metal tube insertion part 2 Narrow tube 3 Through hole 4 Metal tube for gas passage to gas pressure measuring device 5 Gas pressure measuring device (not shown) 6 Coal sample 7 Heating furnace 8 Piston 9 Piston 10 Displacement meter (Figure) (Not shown) 11 thermocouple 12 temperature recorder (not shown)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-188351 (JP, A) JP-A-50-1799 (JP, A) JP-A-63-252234 (JP, A) 60707 (JP, A) Nomura, Arima, Nishi, "Effect of coal properties on gas pressure in coal softening and melting process (Study on expansion pressure of coke oven-1) Materials and processes, March 5, 1991, No. Vol.4, No.1, p.132 Nomura, Arima, Okuhara, "Effect of Coal Packed Bed Thickness on Expandability during Coal Heating (Study on Expansion Pressure of Coke Oven -2) Materials and Processes, 1991 Nomura, Arima, Okuhara, Vol. 4, No. 4, September 5, 2006, “Effect of carbonization conditions on gas permeability coefficient of coal softening layer (Research on expansion pressure of coke oven) -3 "materials and processes, 1992 March 3, Vol. 5, No. 1, p.92 (58) investigated the field (Int.Cl. ^7, DB name) G01N 33/24 G01N 7 / 00-7/22 C10B 57/00-57/20 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. A diameter of 2 to 4 at several different positions in the height direction.
A metal tube having an outer diameter of 2 to 4 mm and an inner diameter of 1 to 3 mm is inserted from the through hole into a predetermined thin tube having one end having a through hole of 1 mm, and a contact portion between the metal tube and the through hole is sealed. A predetermined amount of a coal sample pulverized to a particle size of powder is charged as powder into a thin tube at a predetermined charging density, and a piston having a predetermined load is placed thereon, heated at a predetermined temperature rising rate, and heated in a coal bed. In addition to measuring the pressure of the gas generated in the process, measuring the vertical displacement of the piston due to heating, and measuring the gas generation rate of the same coal sample using a thermobalance, gas pressure distribution, softening
A method for measuring a gas permeability coefficient of a coal bed in a softened and molten state, wherein a gas permeability coefficient is obtained from a layer thickness , a gas density, a gas viscosity, and a gas generation rate per unit volume of a coal bed in a molten state. 2. A thin tube in which a metal tube is inserted from a through hole into a bottomed thin tube having a plurality of through holes at different positions in a height direction and a contact portion between the metal tube and the through hole is sealed; A coal bed in a softened and molten state comprising a heating furnace equipped with a piston mounted on a sample and a bottomed thin tube provided with a thermocouple without a through hole in the other thin tube. Jig for measuring gas permeability coefficient.