JPS61163988A - Producing coke - Google Patents

Abstract

PURPOSE:To produce a coke having a uniform quality by subjecting a pulverized coal in an undried state to determination of particle size and water content and controlling conditions for carbonization and/or charging factors based on the results of the determination. CONSTITUTION:Samples of a pulverized coal in an undried state are each col lected in an amount of 3-5kg per run of sampling at predetermined intervals, supplied to a control feeder 2 via a hopper 1, subjected to determination of water content by means of an infrared moisture meter 3 and supplied to a sifter 5 having a mesh size l(3-5mm) close to the intended particle size. The oversize coal particles is placed in a hopper 6 while the undersize coal particles is placed in a hopper 7. The coal particles in the hoppers 6, 7 are weighed to determine the coal particl size by means of an electronic weigher 9. From the above-obtained data on particle size and water content are calculated the particle size of the pulverized coal in a dry state using the given formula, and the conditions for carbonization and/or charging factors are controlled based on the particle size obtained by the calculation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing coke. More specifically, it relates to the measurement of the pulverized particle size of coking coal and its management in the production of metallurgical coke.

(Prior art) Generally, in the production of coke, the properties of the raw coal vary, but in order to obtain coke of a constant quality, it is necessary to control the carbonization conditions and coal charging specifications depending on the properties. Recognized.

However, this control has not always been carried out sufficiently in the past, and even if it had been done, the particle size after drying of the coking coal was controlled as a factor; The sampled coal was reduced in accordance with the regulations (J Engineering EI MtjlO/), and after drying, it was sieved through a sieve with a constant sieve size and the weight on the sieve was measured.
(Disadvantages of the prior art) The conventional method of sifting has the disadvantage that it takes a considerable amount of time to sieve after drying.
There is a method of estimating the particle size of the dry coal base from the particle size of the obtained wet coal state.
"5i-t-'5ttn" 11 is not emitted and mere estimation based on particle size alone is especially difficult when the moisture fluctuation is large or the moisture is high eVc, estimation of dry coal pace particle size from particle size measurement in wet coal state The accuracy tended to decrease and was unsatisfactory.

(Problems to be Solved by the Invention) The present inventors have improved the drawbacks of the conventional method and provided a method for estimating the particle size of dry coal from the measured values of wet coal with good accuracy. The authors have conducted extensive research to provide a method for controlling the carbonization conditions and charging specifications for coke production based on the differences in wet coal measurements. It has been discovered that highly accurate estimation is possible by estimating particle size based on dry charcoal in consideration of moisture content, and the present invention has been achieved.

(Object of the Invention) An object of the present invention is to provide a control method for quickly responding to changes in the properties of coking coal to obtain a constant coke product of 11Jy2, and more specifically, to measure the state of wet coal. The object of the present invention is to provide the above-mentioned highly accurate control method using only values.

(Contents of the Invention) Therefore, an object of the present invention is to measure the particle size and moisture content of undried pulverized coal, and to control carbonization conditions and/or charging specifications using the measured values as factors. More specifically, the particle size of the undried pulverized coal is converted into the particle size of the dry pulverized coal calculated from the measured value and the measured value of moisture content. Further, more specifically, the conversion is performed by measuring the particle size of the undried pulverized coal by sieving it with a sieve with a sieve mesh size lCva), and calculating the particle size of the dry pulverized coal based on the following formula from the measured value. This is what we propose to do.

R=a*G-)-b*M-1-aHowever, R: sieve size smaller than l and near the target particle size of dry pulverized coal (
m) Yield of dry pulverized coal under the sieve c% after sieving with a sieve having: G: Weight percentage of the undried pulverized coal above or below the sieve M: Measured moisture value of the undried pulverized coal a, b , c: Constant The present invention will be described in detail below, but first, the particle size measuring method used in the present invention will be explained based on the drawings.

FIG. 1 is an explanatory diagram of an example of a particle size measuring method.

In the figure, No is a hopper for pulverized coal, - is a control feeder, J is a moisture meter using infrared absorption spectrometry, A is a drying system installed to actually measure the particle size of dry coal, S is a sieving device,
6 is an upper sieve hopper, RI is a lower sieve hopper, S is a weighing hopper, 9 is an electronic weigher, IQ is an arithmetic unit, and II is a recording mechanism for calculation results such as a printer.

In general, coking coal for coke production is used for iron making, casting, -H
Single coal or blended coal is used, which is obtained by pulverizing raw coal suitable for various types of coke in accordance with a conventional method, and in the case of blended coal, it may be blended and then pulverized.

The moisture content of pulverized coal varies considerably depending on the origin of the raw material and the conditions at the time of storage, and the present invention can cope with a wide range of moisture content fluctuations, but if possible, it is possible to prevent extremely excessive moisture content from occurring. It is preferable to adjust it so that it can be removed because measurement accuracy is ensured. As a guideline for the adjustment, a moisture content of 1 da V, below 9 of the measuring scale, more preferably below the weight of a saw, is adopted.

A sample of the pulverized coal is stripped automatically or manually on a conveyor between the pulverizer and the coal bin, and the sampled sample is placed in a hollow/knee/hole.
A control feeder then transfers a certain amount to the measurement system. The control feeder may be of fixed quantity transfer or of any type if possible, but
The simplest method is to take out the sample at a constant thickness on a belt conveyor.
/~u@/min is measured. The pulverized coal whose moisture content has been measured is then divided into quarters using a sieve [3, but this sieving device can also be selected from a wide variety of types. In the present invention, an example in which an inclined vibrating sieve is used is explained. Pulverized coal is fed to the upper end of the slanted sieve, passes through the sieve to the lower part of the sieve, and is directly stored in the above-sieve hopper 41C. , the lower part of the sieve passes through the sieve in the middle of - and is stored in the lower part of the sieve hole park.
, will be done. In addition, a sieving device! The size of the sieve, the angle of inclination, the degree of imaging, etc. can be determined as appropriate depending on the type and particle size of the coal, but the key factor for measurement is the opening of the sieve, and in the present invention, the opening is A vibrating screen having a size of sieves J to J is most preferably used.

The sieved pulverized coal is first stored in the sieve top water rubber 6 and then transferred to the weighing hopper tIC. good~·. ) Weigh using an electronic scale at 9VC. Next, the damper of the under-sieve hole park is opened, and the coal in the under-sieve hopper 7 is stored in the weighing hopper, fK, and the entire amount is weighed using the electronic weigher 9. Of course, the weighing order may be reversed, that is, the weight under the sieve may be weighed first, and then the weight including the weight on the sieve may be weighed.

In the present invention, the carbonization conditions and/or charging specifications of the coke oven are controlled using the wet coal moisture value and particle size measured in this way as factors (without directly measuring the dry coal particle size). However, it has been found that the particle size of dry coal can be estimated from the measured particle size of wet coal by simply repeating the empirical rule or, preferably, by the following formula, which is highly accurate.

R=a-G-)-b-M+cwherein each letter has the same meaning as defined above, but G most preferably refers to the whole under or above the sieve of undried pulverized coal with sieve size l; The weight ratio is adopted, and the constants a%, b, and c are sieve sizes l and m, and R, G, and M are verified using at least three types of pulverized coal whose particle size distribution is known in advance. This is determined by the trap.

In this case, it is usually desirable that the sieve size j of the undried pulverized coal be around the target particle size, specifically J ” j Ill
selected from the range. Also, what is the sieve size m in the estimated particle size of dry pulverized coal? In the present invention, instead of the particle size of dry pulverized coal, the bulk density is calculated using the same formula as above. However, this may be taken as a factor. Although various conventionally known measuring methods can be used to measure moisture, the present invention significantly shortens the measurement time as a whole and allows for carbonization in a coke oven. Since the purpose is to control conditions and charging specifications more effectively, a method that can measure moisture in the shortest possible time is more appropriate.In this sense, measurement using so-called infrared absorption spectrometry This is the most preferable method, considering the balance with analytical accuracy.

The present invention basically controls carbonization conditions and charging specifications based on the particle size and moisture content of undried pulverized coal, but more preferably dry pulverized charcoal obtained as described above from these two measured values is used. is converted into estimated values of particle size and bulk density, and controlled using this and the above-mentioned moisture as factors.

The estimated value of dry pulverized coal is used for particle size control in coal crushing equipment, predicts charging specifications such as charging bulk density, and is also used as a factor to control coal carbonization conditions such as fuel supply amount and firing cycle. This makes it extremely easy to stabilize coke quality and coke oven operation.

There are no particular restrictions on the heating method used in producing coke to which the method of the present invention is applied, and any conventional uniform heating method or program heating method may be applied and implemented.

Control based on the above-mentioned factors in the present invention is specifically designed as appropriate based on empirical rules for each case of coke oven operation. If the estimated particle size is coarser than the target value, the amount of fuel supplied is increased, and if the estimated particle size is finer than the target value, the amount of fuel supplied is decreased.

Furthermore, if the moisture content of the undried pulverized coal increases beyond the target value (approximately 9%), the amount of fuel supplied tends to be increased, and if the moisture content is less than the target value, the amount of fuel supplied tends to decrease.

Thus, according to conventional methods such as the 51-day method, it took about 3 hours to determine the particle size of dry and pulverized coal because it was sieved after drying, but in the present invention, the particle size is measured online and in the wet coal state. The time! It is significantly shortened to ~/Q minutes. Furthermore, even when the moisture content of the coal varies greatly or the moisture content is high, the determined particle size takes into consideration the moisture value measured in advance, so the estimation accuracy is extremely high and maintains sufficient reliability as a control factor.

Therefore, by implementing the present invention, highly accurate measurement of coking coal pulverized particle size is carried out in real time, which enables active process control by providing feedback to the adjustment of the coal pulverizer, etc., resulting in stable operation in coke production and stable coke quality. It becomes possible to aim for

EXAMPLES Hereinafter, 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 it exceeds the gist thereof.

Example Dry Coal Base 3 Using the method shown in Figure 1, pulverized coal (average moisture value 90% by weight) with the goal of adjusting the weight under sieve to approximately 10% was evaluated for moisture and wet coal conditions. The following (
The weight t91+ of the dry charcoal paste under the Jfll sieve was estimated using the formula 1), and the same particle size measurement value was obtained by actually drying it based on the JIEI method. The results obtained are shown in Table 1.

Also, for reference, the weight percent under the 3fi sieve on a dry coal basis was determined using the following formula (2), which does not take into account the moisture content of 1 coal, and the obtained results are also listed in Table 7.

Q=0.03'l (k+0.3/1M+ri/, 9/ri
・・・・・・(1) Q,'=-0,OJ! rA) −
) - IO, 9 koku - - - (2) However, Q, Q': Estimated value of Jm weight % under sieve (dry coal base G: 1w weight % under sieve (wet coal state) M: Moisture of coal [weight % ) The charged coal particle size and moisture value obtained by the above 4;1Ifk method can be quickly reflected in the furnace operation, that is, the predicted aa
aeegpeaeeeeeeΦ--#-Table 7 OAs a result of controlling the fuel supply amount in accordance with the charging density and carrying out carbonization, the amount of heat required for carbonization can be reduced by several Kcal/l (g-Coal) and fluctuations in coke quality can be reduced. was completed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of a particle size measuring method. L: Undried pulverized coal hopper 2 Control feeder (belt conveyor) J: Infrared moisture meter J: 9-minute device 4: Upper sieve hopper 7 = Lower sieve hopper t: Weighing hopper Digital weigher 1Q: Arithmetic unit

Claims (6)

[Claims] (1) A method for producing coke, which comprises measuring the particle size and moisture content of undried pulverized coal, and controlling carbonization conditions and/or charging specifications based on the measured values. (2) The particle size of the undried pulverized coal is converted into a particle size of the dry pulverized coal calculated from the measured value and the measured value of moisture content as a factor. method for producing coke. (3) The method for producing coke according to claim (1) or (2), wherein the moisture content of the undried pulverized coal is measured by infrared absorption spectrometry. (4) The particle size of the undried pulverized coal is measured by sieving it with a sieve having a sieve mesh (l) close to the target particle size, and the particle size of the dry pulverized coal is calculated from the measured value based on the following formula. A method for producing coke according to claim (2) or (3). R=a*G+b*M+c However, R: Lower yield (%) of dry pulverized coal when sieved with a sieve having sieve mesh (m) smaller than the above sieve mesh l and close to the target particle size of dry pulverized coal ) G: Weight percentage above or below the sieve of the undried pulverized coal M: Measured moisture values of the undried pulverized coal a, b, c: Constants (5) The method for producing coke according to claim (4), wherein the two sieve meshes l and m are respectively l = 3 to 5 mm and m = 2 to 4 mm. (6) The particle size of the undried pulverized coal is measured by sieving it with a sieve having sieve openings close to the target particle size, and the dry pulverization is calculated from the obtained measurement value and the moisture content measurement value using the following formula. The method for producing coke according to claim (1) or (3), characterized in that the factor is converted to the bulk density of charcoal. Q=a'*G+b'*M+c' However, Q: bulk density of dry pulverized coal G: weight ratio above or below the sieve of undried pulverized coal M: measured moisture values of undried pulverized coal a', b' , c′: constant