JPS60101184A - Method for controlling fuel in coke oven - Google Patents

Abstract

PURPOSE:To enable the quality of coke to be kept constant and to reduce the quantity of heat to be consumped, by changing the feed rate of fuel from a high flow rate in the early stage of dry distillation to a low flow rate according to hydrogen concn. in gas generated from a coking chamber or conducting first change to stop fuel supply. CONSTITUTION:In a coke oven, coke is softened and molten at 350-400 deg.C and then resolidified and thermal conductivity is rapidly increased at a semi-coking temp. of 500-600 deg.C. Until temp. reaches this level, fuel is fed at a high feed rate to effect premature coking. Thereafter, the fuel feed is stopped or the feed rate of fuel is extremely decreased, whereby the quality of coke can be kept constant and at the same time, the quantity of heat to be consumed can be reduced. With regard to change in the concn. of hydrogen in gas generated from a coking chamber, the rate of change of hydrogen concn. temporarily becomes zero when the temp. of coal core reaches 500 deg.C, and then the rate of change is gradually increased. Accordingly, the first change of fuel feed is conducted between the points A and D in the figure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling fuel in a coke oven. As one of the energy saving measures in coke ovens,
A so-called program heating method has been proposed in which the amount of fuel supplied to the coke oven is set at a large flow rate at the initial stage of carbonization, and the amount of fuel supplied at subsequent stages is adjusted depending on the purpose.

That is, in this method, after the start of carbonization, the amount of twisted material supplied for 3 to 9 hours is increased to 6 to 2.5 times that in the case of uniform heating, and then the flow rate is reduced to a low flow rate including a zero state about 7 to 3 times. It is something that can be switched.

However, these programmed heating methods are difficult to control in reality due to complicated heating patterns in current coke oven operations, or indicators of specific heating patterns are not clear, or It has drawbacks such as not considering the quality of the coke produced.

Therefore, as a result of repeated studies to solve these problems, we found that the following heating control method during program heating is optimal in terms of reducing heat consumption and maintaining coke quality. I found out.

In other words, when paying attention to the change in thermal conductivity during carbonization of coal, the thermal conductivity increases from the temperature level around SOO~600°C, where coal softens and melts from around 35θ to 00°C, and then resolidifies and becomes semi-coke. Since the temperature rises rapidly, the system aims to maintain coke quality by reducing the amount of fuel supplied to this temperature level to cause early coke formation, and from this point onwards, the amount of fuel supplied is zero or extremely reduced. However, it was found that it was also possible to reduce the amount of heat consumed at the same time.

On the other hand, when programmed heating is performed based on the heating pattern described above, the temperature rise rate in the softening and melting temperature range (3SO~!00'G) becomes faster on average than during normal heating, so Softening and melting properties or fluidity of coal are improved,
As a result, the substrate strength of the produced coke is increased, making it a coke product! (especially the strength after hot reaction) will not improve.
Due to the reduction in coke temperature during nitrogen extraction during program heating (i.e., the reduction in the amount of heat consumed during program heating)
This decrease in coke quality (due to the reduction in coke sensible heat) can be sufficiently compensated for.

Considering the above, the most important point is when the fuel supply amount is reduced from the large capacity at the initial stage of carbonization to zero or extremely reduced.
It can also be determined by empirically knowing the relationship between the elapsed carbonization time and the temperature in the charcoal, but this method is not practical, and the temperature in the charcoal is also determined by one point in the carbonization chamber. The accuracy is poor due to the

Therefore, as a result of various studies on this point, we found that
Vi
We found that there is a close relationship.

That is, one object of the present invention is to switch the fuel supply amount based on measuring the hydrogen concentration in the gas generated from the carbonization chamber.

Therefore, in the programmed heating method, which changes the fuel supply amount at each stage of the coal carbonization process in a coke oven, the fuel supply is changed from a large flow plate at the initial stage of carbonization to a small flow rate. Alternatively, this can be achieved by performing the first switching to stop based on the hydrogen concentration in the scum generated from the carbonization chamber.

Generally, in the carbonization process of coal, the oxygen-containing functional groups in the coal are decomposed relatively early, releasing moisture, carbon dioxide, and the like. This temperature is about 200° C., but when the temperature rises further, thermal decomposition of the coal essence occurs for the first time, and a lot of methane, hydrocarbon gas, tar, etc. are released. This temperature is J! ; In the temperature zone of 0-300°C, the higher-order structure of coal undergoes thermal decomposition and becomes lower molecular weight, increasing its mobility and rearranging its molecules. It re-solidifies at around 200°C, and when the temperature reaches 200-000°C, thermal decomposition progresses further, releasing mainly methane, hydrogen and carbon oxide, and gradually increasing the size of the aromatic structure, while the amount of tar hardly increases. ? When the temperature exceeds 00'Q, the composition of the generated gas becomes rich in hydrogen, and the crystallization of coke is further expanded.

After the carbonization process described above, coke is produced. In the coke oven, this is heated through the carbonization walls on both sides. Since coal has extremely low thermal conductivity, it is heated from both sides of the carbonization chamber. Heat is gradually transferred toward the center, and the above-mentioned thermal decomposition occurs. Therefore, the lower the water content of the charged coal and the higher the temperature of the flue in the combustion chamber, the faster the carbonization will proceed. Figure 1 shows a schematic diagram of the carbonization process. This figure shows, from the left, a heated wall brick, a gap between the brick and coke caused by coke contraction, a coke layer, a semi-works layer, a plastic zone, and an uncarbonized coal seam. After exhibiting a softened and molten state at around 0.degree. C., the coal grains 6 fuse together and generate cracked gas. When this state of thermal decomposition progresses from both sides of the carbonization chamber toward the center, three
5θ~! The gas mainly composed of hydrocarbons and tar vapor generated in the 00°C temperature zone (abbreviated as plastic zone) is caused by cracks caused by the pores and shrinkage of the heated coke on the furnace wall side. The red-hot coke undergoes secondary decomposition in this red-hot coke zone, leaving deposit carbon behind in the coke and becoming a lighter gas that is discharged outside the furnace.

Here, we focus on hydrogen as the l component of hydrocarbons, and consider the thermal decomposition of hydrogen in the coke layer. As a result of various studies, we found that there is a close relationship between the change in hydrogen concentration over time during the middle stage of carbonization and the coal core temperature. It was confirmed. That is, Figure 2 shows a typical example of the measurement results of the hydrogen concentration in the generated gas and the coal core temperature in this furnace. The axis shows hydrogen concentration, furnace temperature, fuel gas supply amount, and coal core temperature. As is clear from Figure 1, the temperature of the coal core is 200.
It was found that the point at which the temperature reached around ℃ and the point at which the rate of change in hydrogen concentration suddenly increased coincided well.

Next, based on the above study results, we will specifically explain how to determine when to switch the fuel supply amount during program heating based on changes in hydrogen concentration that occur during carbonization. .

That is, by analyzing the gas composition generated from the carbonization chamber as carbonization progresses, data on changes in hydrogen concentration with respect to the elapsed time of carbonization is obtained. From the concentration at the seventh point when it became zero,
The rate of change decreases, reaches zero again91, then increases, and the fuel supply amount may be switched within a range up to a first point in time when the hydrogen concentration becomes equal to the concentration at the first point in time. As is clear from Figure 1, the change in hydrogen concentration increases from the beginning to the middle of carbonization, and then the rate of increase becomes zero (AA in Figure 1). Thereafter, the hydrogen concentration decreases at a decreasing rate (point B in FIG. 2), and the hydrogen concentration increases again (region 00 in FIG. 2).

In the present invention, from point A (point l in Figure 2) to point D (first point It is important to change the fuel supply for the first time within the range of The first switching of the fuel supply will take place within a few days.Of course, instead of the above rate of change in hydrogen concentration, a statistical value obtained by statistically processing the change in hydrogen concentration may be used as an indicator of when to switch the fuel supply amount. can.

In addition, a standard pattern for changes in ethylene concentration or tar concentration is set based on operating conditions such as the firing cycle, initial furnace temperature, and furnace body conditions, as well as the properties of the charged coal such as moisture, volatile matter, particle size, and amount of charged coal. Actually, the ethylene concentration or tar concentration in the gas generated from the carbonization chamber is analyzed, and while adjusting the fuel gas supply amount etc. so that the measured value follows the standard pattern, the first change is made to the hydrogen concentration. It may be done based on.

The standard patterns for ethylene content or tar concentration are determined based on the results of statistical analysis of a large number of actual data. Statistical analysis can be performed by classifying performance data and approximating it to standard conditions consisting of several groups. Alternatively, it is also possible to perform a simulation using an electric machine and make a determination based on the result. The concentration of each of these substances can be measured by the commonly used methods such as gas chromatography and mass spectrometry for hydrogen and ethylene, and by using the difference in weight using a tar extractor for cool. It is carried out by

Here, switching the supply amount in the present invention means a significant change in the supply amount such as changing from a large flow rate to a small flow rate or stopping the supply (usually 0.3 times the supply -'' in the case of uniform heating)
Control of the supply amount based on the ethylene concentration involves changing the supply amount slightly so as to follow the reference pattern for each concentration.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist of the invention is exceeded. Note that the physical property values on the Hisao side are values measured by the following method.

Note that the operating rate used in the present invention is defined by the following equation.

Coke oven operating rate = (2 da/total carbonization time (hr month x 1
00(1) Charging coal properties Ash content (Ash): , 718M g/kg Volatile matter (VM
): 718 Mg 112 Gisseler fluidity (F): 118 Mg 0/Average reflectance (R): 518 Mg/6 Total sulfur content (Suυ: JIS M l:!;/3 Total Inner H 妓CTI) : JIS M ltgI&(2
) Strength after hot reaction (O8R) Sample particle size: , 20 mrk Itt+m sample heavy lid: ,
2ootiy times gas composition: 00. (100%) Gas flow rate = jNl/min Reaction temperature: 1toooC Reaction time: 1-0 min Intensity: After 6θQ rotation with type 1 drum (Orpm x
30 minutes) wt% on 1OyspJli (3) Cold drum strength (D snow) JIS K Col! l Example 1 Width 000mm, length l, J'rrLs height 41. j
Charge the blended coal with the properties shown in Table 1 into the carbonization chamber of 7IL,
Carbonization was carried out using coke oven gas as fuel.

The hydrogen concentration and its rate of change at the time of switching the fuel supply amount (when the supply amount is zero) are shown in Figure 3 (operation rate/k
kchi, fire fall time: /3 hours λ7 minutes), Figure 1 (operation rate l
JS staff, fire fall time near 6 hours/J minutes):iai
'). And in % Figure 3, 9 after the start of carbonization.
．． Since the rate of change in hydrogen concentration became zero at 1 hour, the rate of change in hydrogen concentration was approximately 0.
After Zhr, the fuel supply amount was changed. In addition, in Figure D, the rate of change in hydrogen concentration reached zero at 41 hours after the start of carbonization, so it was approximately 0. After k hr, the fuel supply amount was switched.

Carbonization was carried out in this manner, and coke was extruded approximately one hour after the coke had ignited. The average particle diameter, cold drum strength and strength after hot reaction of the obtained coke were measured, and the results are shown in Table 2.

As is clear from Table 2, the present invention is very effective as a fuel control method during programmed heating since sufficient fuel reduction rates and coke quality are obtained.

Table 1 Charging coal properties Table 1 Results

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the carbonization process in a coke oven carbonization chamber, Figure 1 is a diagram showing changes in hydrogen concentration in coke oven generated gas and coal core temperature, Figures 3 and q are: FIG. 3 is a diagram showing changes in hydrogen concentration and fuel gas supply liquid in an example. Applicant: Mitsubishi Chemical Industries, Ltd. Agent: Yo Hase - (and 1 other person) Hand MneflJ, iJyo (Set 6) 1 Indication of matter f1 1982 Tokutoku 6'F Application No. 208869 2 Invention Name: Coke Oven Fuel Control I Method 3 Persons subject to amendment 1 Relationship 4JImu' [Applicant J91 Mr. 2-5-2 Marunouchi, Chiyoda-ku, Tokyo
Name (59G) Suzu, Representative Director, Mitsubishi Chemical Industries, Ltd.
Sei Ki 24 Agent 5 Mitsubishi Chemical Corporation, 2-5-2 Marunouchi, F Daita-ku, Tokyo 100 Japan Daily publication of amendment order February 28, 1980 (shipment date)
6. Illustration of the amendment Drawing 7 Contents of the amendment Procedural amendment as attached (voluntary) 111+ Showa to March 27, 2015 - Director General of the Japan Patent Office Kazuo Wakasugi 1 Indication of the case 1986 Patent Application No. 20 Doza No. 69 No. 2 Name of the invention Fuel control method for coke ovens 3 Person making the amendment Patent applicant address 2-6'4 Mλ, Marunouchi, Chiyoda-ku, Tokyo Name (, t9.g) Representative Director, Mitsubishi Chemical Industries, Ltd. Ken Suzuki 24 Agents 〒100 (1 other person) (1) "Capacity" on page 91, line 19 of the specification is corrected to "flow rate." (2) Specification number! Change "Temperature in charcoal" from page 7 to line λ to "
The temperature at the center of the coal filled in the carbonization chamber (hereinafter simply referred to as coal core temperature) is corrected. (3) Correct the "temperature in the coal" to the "coal core vorticity". (4) Lines 10, 72, and 11 of page 1 of the specification
The "coal core temperature" on the 76th line and the 76th line are corrected to the "coal core temperature." (5) Book 1 of the 4th page? Page 20th line to 9th door line j, "Next, there will be one or more........namely,"
In the following detailed explanation of the present invention, in the programmed heating method applied to the present invention, fuel is supplied in a large flow during the carbonization W period of coal, which is filled in the carbonization chamber. In order to rapidly increase the width of the coal, it is desirable to supply at least 7.2 times the fuel supply in the uniform heating method.The larger the supply amount, the better. For forged products. High temperature 5. It is necessary to keep the temperature within a range that does not cause any adverse effects due to localized heating.Specifically, it is set depending on the structure of the furnace, combustion method, etc., but 1. Normally, it is 7.2 to 3 for uniform heating. The flow rate may be selected from the range of 3 times to 2.3 times, preferably 3 to 2.3 times.Of course, this flow rate does not need to be constant; The small flow rate, where the amount of fuel supplied is zero, refers to the range from about OJ times the amount supplied in the case of uniform heating to completely stopping the supply. "To do that," he added. (6) In the 9th negative/B line of the specification, "slightly misrepresented" is corrected to "decreased." (For example, if you fill the specification with dry glass wool and fill it with a temperature of 100~/λO℃, The gas generated in the carbonization chamber is passed through a tar collector maintained at a constant temperature of 11 m degrees at a constant flow rate, and the change in weight of the tar collector per unit time is measured.'' (8) Details Add the following statement to the first line of page 1 of the book: "Then, once the fuel supply -: has been switched from a large flow rate to a small flow rate including zero state. A method of maintaining the same state until approximately 0.j to j hours before the start of the flow, or a method of cutting and burning a large flow rate and a small flow rate including a zero state twice or more times in a pulsed manner. However, it is preferable to maintain the coke oven in the same state because the operation is simpler and the temperature of the coke oven can be easily controlled. After the carbonization of the coal proceeds rapidly and the extrusion operation is carried out after the coal has cooled down, it is preferable to raise the furnace wall temperature of the carbonization chamber and switch to the same flow rate in preparation for the first coal charging. The timing of switching should be before θ, j~8! of coke extrusion so that the predetermined temperature is reached during the next charging.The timing of the channel can be determined by measuring the coal core filling degree. (9) Specification No. 1/Page No. B "Ethylene d degree" in the row
Insert "ethylene concentration or tar concentration" below. [As detailed above, the present invention performs the initial switching of the fuel supply amount in the programmed heating method based on the hydrogen concentration in the coke oven gas generated from the carbonization chamber.
The switching timing can be determined accurately and easily. Further, as is clear from the examples described later, a large fuel reduction rate and a sufficient coke quality can be obtained. Furthermore, control the amount of fuel supplied. If the ethylene concentration or tar concentration follows the respective standard patterns, f[
Since tlJ control is easy, the present invention is very useful as a fuel control method when implementing the programmed heating method. ” Ov Details 1: Change the “Coal core temperature” in the 76th member, G line to “
Correct with the coal core saturation J. 11 boxes□ Kano = Yo =

Claims (1)

[Claims] (1) In a programmed heating method in which the amount of fuel supplied is changed at each stage of the coal carbonization process in a coke oven, the fuel supply is changed from a large flow rate at the initial stage of carbonization to a small flow rate. A fuel control method for a coke oven, characterized in that the first switching to start or stop is performed based on 1l11 degrees of hydrogen in gas generated from a coking chamber. (2) In the programmed heating method, a reference curve for ethylene concentration or tar concentration is set based on the operating conditions of the coke oven and the charging specifications of the charged coal, and the The first switching is performed based on the hydrogen concentration while measuring the ethylene concentration or the tar concentration and controlling the amount of fuel supplied so that the deviation between the measured value and the set value becomes small. A method according to claim 1. A method according to claim 1 or claim 1, characterized in that: (4) When the hydrogen concentration is first switched, the rate of change in the concentration decreases from the concentration at the first time when it once becomes zero, becomes zero again, and then increases, and the hydrogen concentration ゛ changes to the first point. The method according to claim 1 or 1, characterized in that it is carried out within S times up to the first time point, which is equal to the concentration at the time point.