JPS63186796A - Thermal reforming of coke oven by-products - Google Patents

Abstract

PURPOSE:To attain thermal reforming of coke oven by-products, especially improvement in the tar quality, by conducting coal charge in portions according to a particular method in coke oven operations. CONSTITUTION:In code oven operations, thermal reforming of coke oven by- products is accomplished by first supplying 1/2-2/3 of the whole of coal to be charge and supplying the remaining coal at once or in portions over a period up to the coking time so as to conduct carbonization. Thus it is possible to attain advantageous, effective improvement in tar quality without the necessity of making special investment in facilities.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for thermally reforming coke oven by-products.

(Prior Art) A coke oven produces coke by carbonizing coal, and at the same time produces coke oven gas and chemical products as by-products. It has been known for a long time that the quality of tar, in particular, among chemical products, is largely controlled by the combustion chamber temperature (temperature at the upper part of the coking chamber) of a coke oven, the residence time in the coking chamber, and the like.

FIG. 2 shows the relationship between the temperature at the top of the carbonization chamber and tar QI (quinoline soluble content), and FIG. 3 shows the relationship between the residence time of the by-product in the carbonization chamber and tar QI. From FIG. 2, it can be seen that the tar QI is about 1% below 850°C, and can be greatly improved when the temperature exceeds 850°C. This is because methane (CH4) contained in coke oven gas is thermally decomposed into carbon (C) and hydrogen (H2) as the heating temperature increases, so hydrogen (H2) in coke oven gas increases.

When tar is heated at high temperatures, ether bonds are thermally decomposed and side chains, such as alkyl groups, are separated, promoting polycondensation, increasing aromaticity, and increasing quinoline solubility QI. Furthermore, it can be seen from FIG. 3 that the longer the residence time of the by-product in the carbonization chamber, the higher the tar QI.

Therefore, as a technology to control the quality of tar,
As shown in Japanese Patent Application Laid-open No. 59-172584, there is a light charging operation in which the amount of coal to be charged is controlled to enlarge the upper space of the carbonization chamber, and thermal reforming is carried out there. There is a method of adjusting the gas temperature in the upper part of the carbonization chamber, as disclosed in Japanese Patent No. 61-120890.

(Problems to be Solved by the Invention) However, in the technique disclosed in the above-mentioned Japanese Unexamined Patent Publication No. 172584/1984, there is a problem in that it is not possible to secure a production volume commensurate with the capacity of the furnace because the amount of coal charged is reduced. There is. The latter technique, disclosed in JP-A No. 61-120890, attempts to thermally reform byproducts by increasing the upper temperature of the combustion chamber. When the temperature is too low, there is a problem in that the temperature in the gas path of the coking chamber cannot be raised to the target temperature, and thermal reforming of by-products can hardly be expected.

(Means for Solving the Problems) It is an object of the present invention to provide a method for thermally reforming coke oven by-products that advantageously overcomes the drawbacks of such conventional techniques. The gist of this is that in the operation of a coke oven, 1/2 to 2/3 of the total amount of coal is initially charged, and the remainder is charged and carbonized in one lump or in parts until the fire-off time. This is a method for thermally reforming coke oven byproducts.

In coke oven operation, carbonization is normally completed for about 200 hours after coal is charged (this is called the fire-off time), and then the coke is kept in the carbonization chamber for about 2 hours in order to mature the coke, stabilize coke quality, and facilitate extrusion work. It is normal to leave it alone (this time is called the leave time). The fire-off time is adjusted by the combustion chamber temperature according to the amount of coke produced. When the production volume is low, the combustion chamber temperature is lowered and the fire-off time is delayed.

Normally, the standing time is about 2 hours, but if the production volume is low, the furnace temperature is kept to a minimum and the standing time is extended to adjust the production volume.

In the operation of a coke oven as described above, the present invention divides the charging of coal into multiple times and charges the by-products generated during carbonization of the initially charged coal by charging a small amount of coal. Thermal reforming takes place in the space above the carbonization chamber. Then, until the coal charged for the first time is carbonized, an amount of coal corresponding to the furnace capacity is additionally charged. This makes it possible to effectively prevent a decrease in production relative to the furnace capacity during light charging.

The present invention will be described in more detail below.

In the present invention, when charging coal, at first 1/2 to 2 of the total amount of charged coal is charged.
After charging 1/3 of the coal and starting carbonization, the remaining coal is charged several hours after the initial charging. The number of times the charging should be divided is two or more times, but in consideration of workability, two times is best. Further, the charging timing after the second time may be any appropriate timing up to the fire-off time, but it is necessary to ensure enough time for the coal charged last to carbonize sufficiently.

By-products generated by the carbonization of initially charged coal pass through the high-temperature part of the space in the coking chamber where coal is originally charged, and due to the expansion of the upper space, this By-products due to extended residence time in the part,
In particular, the quinoline solubility QI of tar is greatly improved. Good quality tar will continue to be produced until the second charge is made. In other words, the average level of tar QI is a mixture of the good quality tar generated initially and the normal tar generated later.

Here, the amount of coal initially charged is 1 of the total amount of coal charged.
A ratio of about 1/2 to 2/3 is desirable, and if the amount of coal is further reduced, the upper part of the furnace lid will be overheated, causing the furnace lid to warp and raw gas to leak, which is not environmentally preferable. Also, if there are more people than V3,
The upper space of the carbonization chamber becomes small and the targeted tar reforming effect is small.

FIG. 1 shows the relationship between the elapsed time after coal charging and the temperature in the upper space of the coking chamber when the method of the present invention is adopted. For comparison, the conventional method of charging the entire amount at once and the light charging method are also shown.

In the method of the present invention, at the initial stage of carbonization, the temperature in the carbonization chamber is about 200° C. higher than that of the conventional method, and also about 120° C. higher than that of the light loading technology in which the amount of coal charged is reduced by 7 inches. Due to this high temperature, the by-products mainly generated during the carbonization of the initially charged coal can be thermally reformed, and the by-products of the second and subsequent coal charges can also be thermally reformed. Furthermore, since the initially charged amount of coal is 1/2 to 2/3 of the total, the upper space of the carbonization chamber is large, and the residence time of the by-products can be increased, so that the thermal reforming effect in this respect is also large.

(Fu Example) In a coke oven whose carbonization chamber has a height of 5 m, a width of 0.43 m, and a length of 13.4 m, 2/3 of the total coal t is initially charged,
When I charged the remaining 1/3 after 2 hours, the tar QI was 2.
．． It rose to 0-2.5%.

Also, if the second charging is done 3 hours later, the QI will be 2.
．． It rose from 7% to 3.3%. These are summarized in Table 1.

Table 1 shows that it is possible to control the tar quality by adjusting the timing of the second charging.

(Effects of the Invention) As described above, according to the present invention, tar quality can be efficiently and advantageously improved without special equipment investment. or,
By adjusting the timing of the second and subsequent charging, it is possible to control the degree of thermal reformation of the tar, and to systematically produce the tar required for the kneading process, as well as to increase the production capacity of the furnace. This shows the excellent effects that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the relationship between the temperature in the upper space of the carbonization chamber and the elapsed time after coal charging according to the present invention in comparison with the conventional technology, and FIG. Figure 3 shows the relationship between temperature and tar QI.
It is a figure showing the relationship with I. Fig. 1, 0 coal narrowing jejt*@M(Hr) Fig. 2

Claims (1)

[Claims] In the operation of a coke oven, 1/1/2 of the total amount of coal charged is initially
A method for thermally reforming coke oven by-products, characterized in that 2 to 2/3 of the coke oven by-product is charged, and the remainder is charged and carbonized in one lump or in parts until the burn-off time.