JPH01252693A - Coke quality control method for coke oven - Google Patents

Abstract

PURPOSE:To stabilize coke quality, by designing a model for predicting coke quality from the properties of charging coal and other particular factors and accurately regulating charge coal formulation and oven temp. in the operation of a coke oven. CONSTITUTION:In the operation of a coke oven, a model for predicting coke quality (such as DI, CSR, ASH and S) after carbonization is designed from the properties (such as properties of simple coal, mixing conditions, water content, expansion coefficient, and volatile content) of charging coal and as four factors, i.e., thermal property values (such as specific heat and heat conductivity), charging conditions (such as bulk density of charging coal), carbonizing conditions (such as oven temp. and carbonizing time) and oven body conditions (such as oven width and brick thickness and thermal properties of a heat transfer wall), and the regulation of charge coal formulation during take-off of charge coal and the regulation of oven temp. during carbonization are accurately performed.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a coke quality control method for a coke oven that controls coke quality to a target value in order to obtain coke of stable quality. (Prior Art) Generally, iron making The quality of coke, the raw material, has a major impact on blast furnace operation. Therefore, it is extremely important to adjust coke quality to a predetermined value. In addition, by reducing variations in coke quality, target quality can be achieved. It is now possible to get closer to the specifications, improving the basic unit of raw material and heat consumption. In order to maintain stable coke quality, it is important to adjust the raw material mixture and control the furnace temperature. Management is carried out separately. The coke oven raw material mix adjustment is based only on the properties of the charged coal]
- This is done in order to estimate the quality of the text and make the quality constant. Further, furnace temperature management is defined by an index that can automatically detect fire extinguishment (for example, Japanese Patent Application No. 133495/1982), and the time from coal loading to fire extinguishment (fire extinguishing time) is defined as a constant.
The furnace temperature is controlled by the combustion control method described in Japanese Patent No. 159877. According to such a method, it is possible to suppress variations in the fire-off time, set a longer target fire-off time, and reduce the amount of heat of carbonization by lowering the furnace temperature. [Problems to be solved by the invention] In the conventional raw material blend adjustment method implemented to stabilize coke quality, charging conditions and carbonization conditions are not taken into consideration when estimating coke quality. carbonization time)
It is very difficult to make adjustments when operating conditions such as heat and furnace temperature are changed significantly. Therefore, it was necessary to measure coke quality and feed back the results to readjust the cutting ratio of coke raw materials. However, the coke raw material charging conditions and carbonization conditions for which the coke quality was measured are different from the coke raw material charging conditions and carbonization conditions that are to be supplied to the coke oven at the time of adjustment. Because of the time delay, they often do not match, which limits the ability to improve control accuracy. In addition, there are multiple transfer brands whose coke quality to be controlled is also a manipulated variable, and it is extremely difficult to determine the manipulated variable by trial and error. On the other hand, as mentioned above, furnace temperature management is achieved by adjusting the furnace temperature so that the time from charging coal to extinguishing the fire is constant.
As a result of suppressing variations in fire-off time and being able to set a longer target fire-off time, the amount of heat of carbonization can be reduced. Reducing the variation in fire-off time indirectly leads to reducing the variation in coke quality, but it has no effect on the resulting quality. This invention has been developed in light of these problems in the conventional technology, and its purpose is to improve quality by accurately adjusting the raw material blend during raw material cutting and adjusting the furnace temperature during carbonization. The purpose of this paper is to propose a method for producing stable coke. (Means for Solving the Problems 1) This invention solves the following problems: charging conditions (charging coal bulk density, etc.), carbonization conditions (furnace temperature,
The coke quality after carbonization (DI
, C8R. This method uses a model to estimate coke (ASH, S, etc.), adjusts the raw material mix during raw material cutting, and adjusts the furnace temperature during carbonization, thereby making coke quality constant. In a coke oven equipped with multiple tanks, the coke quality estimation model calculates each value obtained by multiplying the absolute value of the difference between the predicted quality value of the coke product after each coke raw material composition change and its target value by a predetermined weighting coefficient. All raw materials with a value obtained by multiplying the added value for quality and the absolute value of the difference between the cut-out weight ratio after the composition change for each raw material tank and the standard cut-out weight ratio determined in advance for each raw material tank by a predetermined weighting coefficient. In order to minimize the sum with the added value for the tank, the cut weight ratio for each raw material tank is manipulated and the raw material mixture is adjusted.In addition, the above coke quality estimation model is used to calculate the The added value for each quality of the value obtained by multiplying the absolute value of the difference between the predicted value of the quality of the coke product and its target value by a predetermined weighting coefficient, the changed furnace temperature and the predetermined reference furnace temperature. The gist is a method of manipulating the furnace temperature in order to minimize the sum of the absolute value of the difference between the two values multiplied by a predetermined weighting coefficient. (Function 1 In this invention, for example, the quality DI (strength) of coke
As a model for estimating
A coke strength estimation method described in the above publication is known. This method is a method in which the coke strength of the briquette coal part and the pulverized coal part is estimated, and then the weighted average is calculated according to the weight ratio of both parts at the time of coking. However, in reality, the following (
Introducing the drift compensation amount δi expressed by equation 1), and adding this to the model estimated value Y stiffness, yt is calculated using equation (2) below.
A method is used to calculate the predicted value Yi. to ・(-) J=(h +gp((Yot"'-YMi(0))
-(Yo*(-'Y y i'″))) 10g r
(Yo; (0) Yui (0) - δ1 question... (
1] Yi ”YMi+δ, ・・
...(2) However, YI: Coke quality (DI,
C5R, ASH. S, etc.) δi (-previously calculated δ1 gi: integral gain g for coke quality i,
: Proportional gain Yoi for coke quality i):
Latest measured value of Yi YMl(0): Model estimated value of Yl corresponding to Yo1(0) Yo, (-), Previous measured value of Yi of Yo, (0) YMt(-): Yol(-) Corresponding model estimate of Yl By the way, while stabilization of coke quality is required, the cut-out weight ratio of various raw materials is desirable from the viewpoint of raw material inventory and raw material supply, and the existence of a furnace temperature that is desirable from the viewpoint of operational stability of the coke oven. do. Therefore, in order to satisfy these multiple demands, a standard value is set for the cutting weight ratio and furnace temperature, and a control method is adopted that satisfies both this standard value and the target value for coke quality to some extent. The present invention was made from the viewpoint that it is practically useful. The raw material blend adjustment method of this invention can be explained using the following formula (
3) F, which should minimize K expressed by the formula, is calculated by a known target planning method, and the cut-out weight ratio is manipulated according to this F. K=ΣWyIXIYt-Yll+2'wpjXIFHF
jl - (3)] However, WYi: Weighting coefficient Yi assigned to coke quality Y: Target value of Y, Wp4: Weighting coefficient F4 assigned to the jth raw material tank:
The cut-off weight ratio to be operated for the j-th raw material tank is 1: the standard cut-out weight ratio determined for the j-th raw material tank.The weighting coefficient WYi assigned to the coke quality YI is determined by the degree of stabilization of each coke quality. Also,
The weighting coefficient W, j assigned to the j-th raw material tank is also determined by the degree to which deviation from the reference value is allowed. Next, the furnace temperature adjustment method of this invention is explained using the following formula (
4) The value under which L expressed by the formula should be minimized is calculated using a known target programming method, and the furnace temperature is controlled according to this T. L=ΣWYi X l Yi YI l + WT
X l T-〒1-(4 squares, WT: Furnace temperature weighting coefficient T Two-unit rate Furnace temperature Also, the furnace temperature weighting coefficient wT is also determined by the degree to which deviation from the reference value is allowed. In practice The combustion in the coke oven is controlled by setting the above-mentioned furnace temperature to the target furnace temperature. Fig. 1 is a schematic diagram showing the coke quality control system of the present invention. That is, charging coal cut from a coking coal paddle properties (single coal properties, blending conditions, moisture content, etc.), thermophysical properties, charging conditions (burden coal bulk density, etc.), carbonization conditions (furnace temperature, carbonization time, etc.), furnace body conditions (furnace width, (hot wall brick thickness, etc.) are input into the quality prediction control model and carbonization heat control model to predict the coke quality after carbonization, and based on this predicted value, adjust the mixture of the coking coal tank and adjust the furnace temperature. At that time, the added value for each quality of the value obtained by multiplying the absolute value of the difference between the predicted quality value and the target value after each coke raw material composition change by the weighting coefficient assigned to the coke quality, and the cut weight after the composition change. Each raw material is divided so that the sum of the sum of the absolute value of the difference between the ratio and the standard cut weight ratio predetermined for each raw material tank, multiplied by a predetermined weighting coefficient, for all raw material tanks is minimized. The furnace temperature is adjusted by adjusting the absolute value of the difference between the expected quality of the coke product after changing the furnace temperature and its target value, multiplied by the weighting coefficient of the furnace temperature. The furnace temperature is manipulated so that the sum of the added value and the value obtained by multiplying the absolute value of the difference between the changed furnace temperature and the predetermined reference furnace temperature by the weighting coefficient of the furnace temperature is minimized. (Example) Table 1 shows the effect of reducing variation in coke quality (σ) when this invention method is applied to an actual machine in comparison with the conventional results.As is clear from Table 1. , it can be seen that this invented method can reduce the variation in coke quality. Table 1

【Effect of the invention】

As described above, this invention uses a model that accurately estimates the quality of coke after carbonization from the properties and thermophysical properties of charging coal, charging conditions, carbonization conditions, and furnace body conditions to determine the raw material composition at the time of raw material cutting. This method stabilizes the quality of coke by adjusting the furnace temperature during carbonization, and it is extremely easy to determine the amount of operation, and it also reduces variations in coke quality and stabilizes blast furnace operation. You can expect it. Furthermore, the effect of reducing variations in coke quality makes it possible to bring target quality closer to specifications, and improve raw material and heat consumption consumption.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a coke quality control system of the present invention.

Claims (1)

[Claims] 1. From the four elements of charging coal properties (single coal properties, blending conditions, moisture, expansion rate, etc.), thermophysical property values, charging conditions, carbonization conditions, and furnace body conditions, after carbonization coke quality (DI, CSR, AS
A method for controlling coke quality in a coke oven, characterized in that coke quality is made constant by using a model for estimating (H, S, etc.), adjusting the raw material mixture when cutting raw materials, and adjusting furnace temperature during carbonization. 2. In a coke oven equipped with multiple raw material tanks that store various coke raw materials separately, the coke quality after carbonization is determined based on four factors: the properties and thermophysical properties of the charging coal, charging conditions, carbonization conditions, and furnace body conditions. A model that estimates the quality of coke products after each coke raw material composition change is calculated by adding the sum of the absolute value of the difference between the predicted quality of coke products and its target value multiplied by a predetermined weighting coefficient, and the sum of the values for each quality. The sum of the absolute value of the difference between the cut-out weight ratio after changing the composition for the raw material tank and the standard cut-out weight ratio predetermined for each raw material tank, multiplied by a predetermined weighting coefficient, and the added value for all raw material tanks. 1. A coke quality control method for a coke oven, which comprises controlling the cut weight ratio of each raw material tank and adjusting the raw material composition in order to minimize the amount of coke produced. 3 Charging coal properties (moisture, expansion rate, etc.) and charging conditions (bulk density, etc.)
However, in coke ovens where measurements are taken during or before carbonization, these values are used to determine the coke value after carbonization based on the four elements of charging coal properties, thermophysical properties, charging conditions, carbonization conditions, and furnace body conditions. The added value for each quality of the value obtained by multiplying the absolute value of the difference between the predicted value of the quality of the coke product after changing the furnace temperature and its target value by a predetermined weighting coefficient using the quality estimation model, and the value after the change. A coke oven characterized in that the oven temperature is manipulated to minimize the sum of the absolute value of the difference between the oven temperature and a predetermined reference oven temperature multiplied by a predetermined weighting coefficient. Quality control method.