JP2563483B2 - Coke oven operating method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for operating a coke oven in which any tar quality can be stably obtained.

[Prior Art] It is said that the tar generated in the coke oven is generated by thermal decomposition when the primary tar (low temperature tar) generated at 300 to 550 ° C in the carbonization chamber passes through the gas passage above the carbonization chamber.
Quinoline insoluble matter present in tar (hereinafter abbreviated as QI)
Is qualitatively known to vary with the extent of this thermal decomposition.

QI is a polymer resin material also called α-resin, and its required value varies depending on the use of tar. For example, when used as a raw material for impregnated pitch, needle coke, carbon fiber, etc., a low QI value is required, and when used as an artificial graphite electrode raw material, the QI (value) is 6-9.
%, That is, a high QI value is desirable. Therefore, in coke ovens, different furnace groups operate differently in order to produce tar showing a QI value corresponding to the required value.

At present, tar QI value management is based on the flue temperature by furnace group,
In other words, it is implemented by changing the temperature of the lower burner of the combustion chamber flue. However, changing the flue temperature also changes the operating rate of the coke oven, which may hinder the coke production plan.

For this reason, if there is no coke oven that directly produces tar with the required QI value, multiple tars with different QI values obtained by operating multiple coke oven clusters at different operating rates should be blended as appropriate. I have to respond. In this way, it is extremely difficult to manufacture the amount of coke commensurate with the blast furnace operation at a lower cost and simultaneously achieve the coke furnace operation corresponding to the QI value of tar as described above. Further, it is extremely difficult to adjust the QI value of tar to any value.

As a countermeasure, for example, in JP-A-59-172584, a coke characterized by thermally reforming a carbonization by-product passing through this space in the space above the carbonization chamber created by adjusting the height of the charging coal. A method for modifying a furnace by-product is disclosed in Japanese Patent Laid-Open No. 61-
In 9491, a coke oven characterized by having an adjusting mechanism for adjusting the temperature of the upper space in the carbonization chamber, and in JP-A-61-120891, there is no hindrance to the original operation of the coke oven. , A method of separately collecting tar having a high QI value and tar having a low QI value, and JP-A-61-120890.
In the gazette, in the operation of the coke oven, when the QI value in the tar generated from the coke oven is controlled to 1 wt% or less, the temperature in the upper gas passage of the coke oven carbonization chamber is adjusted within the range of 750 ° C to 850 ° C, and the QI value In the case of controlling at 1% or more, a coke oven operating method is proposed which is characterized by adjusting the temperature of the upper gas passage in the coke oven carbonization chamber to a range of approximately 850 ° C to 950 ° C.

[Problems to be Solved by the Invention] However, the method according to Japanese Patent Laid-Open No. 172584/1984 has problems that the production amount of coke is reduced and the heat consumption of the coke oven is increased. In addition, the above-mentioned
The 61-9491 publication requires modification and addition of equipment. Further, in Japanese Patent Laid-Open No. 61-120891, it is necessary to modify the equipment to provide two or more tar recovery systems. Further, in JP-A-61-120890, it is necessary to change the calorie of the fuel gas in order to adjust the temperature of the top of the flue, and it is difficult to adjust the temperature.

An object of the present invention is to provide a method for operating a coke oven so that tar having an arbitrary QI value can be stably obtained without impairing the original operation of the coke oven.

[Means and Actions for Solving the Problem] In order to achieve the above object, the coke oven operating method of the present invention is such that, in the operation of the coke oven, the flue temperature is set to T ₁ when adjusting the flue temperature of the combustion chamber. After the temperature is raised to 1, the coal is charged, and the flue temperature is raised to T _max at a time of 10 to 40% of the total carbonization time (t), and then,
The temperature is raised to T _{max in} t ₂ hours, and then 5 to the total dry distillation time
(EN) A method for operating a coke oven, characterized in that the quinoline insoluble matter in tar is adjusted by raising the temperature to T ₁ which is the initial condition in 10% of the time.

However, t: Total dry distillation time (hr) t ₁ : 10 to 40% of t (hr) t ₂ : t- (t ₁ + t ₃ ) (hr) t ₃ : 5 to 10% of t (hr ) T ₁ : 1000 to 1200 ° C T _max : 1400 to 1300 ° C T _min : 900 to 800 ° C The present invention will be described in detail below.

In the coke oven, coal changes into solid, liquid and solid,
It produces coke, which is the main product, and by-products (tar, gas). This process is complicated by the entanglement of water evaporation, volatilization and transfer of primary tar and hydrocarbons and secondary decomposition reaction, and changes in the furnace conditions due to coke shrinkage. In order to clarify these in-reactor phenomena, the present inventors conducted a study on thermal decomposition of coal, in-reactor migration of primary organisms, and thermal decomposition of primary tar. As a result, the rate of QI formation in tar was determined by the secondary decomposition temperature and the secondary decomposition time, as shown in Fig. 2, and it was found that the secondary decomposition temperature is particularly important. Here, the secondary decomposition temperature is a decomposition temperature at which the primary tar, which is generated up to a temperature of about 600 ° C. when the coal is carbonized, decomposes to become the final tar (secondary tar).

When considering the state of dry distillation in an actual coke oven, the secondary decomposition temperature mainly corresponds to the temperature of the upper gas passage in the carbonization chamber, and the secondary decomposition time corresponds to the residence time of the gas in the upper gas passage in the carbonization chamber.

Here, the upper gas passage temperature of the carbonization chamber refers to a space through which gas formed between the uppermost part of the coal bed charged in the carbonization chamber and the ceiling brick of the carbonization chamber passes.

On the other hand, as a result of tracing the generation behavior of tar in the carbonization test in the test coke oven, as shown in Fig. 3, 11
In the case of dry distillation at 50 ° C., it was found that 50% of the total amount of tar was generated in the dry distillation time of 3 to 4 hours, and as shown in FIG. 4, heavy tar generation was remarkable in the latter stage of dry distillation.

From the above test results, it was clarified that tar was mostly generated in the first half, and at this time, increasing the temperature of the upper gas passage in the carbonization chamber increased the tar heavier, that is, the QI in the tar, and the QI in the generated tar. It was found that it is important to adjust the temperature of the upper gas passage of the carbonization chamber in order to adjust it.

If the temperature of the upper gas passage in the coke oven of the coke oven is the same in the structure of the combustion chamber, the calories of the fuel gas are the same, and the charging situation of the charging coal is the same, as shown in Fig. It has a close relationship with the flue temperature used for control.

From this, it is sufficient to adjust the flue temperature of the combustion chamber in order to adjust the gas passage temperature in the upper part of the carbonization chamber.

The reason for limiting the flue temperature and the dry distillation time according to the present invention will be described below.

FIG. 1 shows the relationship between the dry distillation time and the flue temperature of the present invention. Here, T ₁ is a flue temperature at the time of charging coal into the coke oven carbonization chamber, and is set to 1000 to 1200 ° C. If it is less than 1000 ℃, there is a problem in coke oven furnace body protection and coke quality.
If it exceeds 00 ° C, there is no technical problem, but there is a loss in terms of energy.

T _max is the maximum flue temperature in the carbonization process, which is 1400-1300
℃. If it exceeds 1400 ° C, there is a problem in terms of protection of the coke oven furnace body, and if it is less than 1300 ° C, there is no effect in terms of making tar heavy.

T _min is the minimum flu degree in the carbonization process and is set to 900 to 800 ° C. If the temperature is lower than 800 ° C, there is a problem in terms of protection of the coke oven furnace body, and if the temperature is higher than 900 ° C, there is no effect in terms of target tar weighting and it is disadvantageous in terms of energy.

T _end is the flue temperature at the _end of carbonization, and is the temperature equal to T ₁ from the operation side of the coke oven. Considering the cycle of coke oven operation, it is necessary to restore the initial conditions.

t ₁ is the time from when coal is charged into the coke oven carbonization chamber until the flue temperature reaches T _max , which is 10 times the total dry distillation time (t).
~ 40%

Considering the combustion mode of the coke oven, a temperature rise of less than 10% is not preferable, so avoid less than 10%. On the other hand, considering the reforming of tar that occurs in large quantities in the initial stage, it is not necessary to spend more than 40% of the time.

t ₂ is the time required for the flue temperature to change from T _max to T _min , and is defined by t ₂ = total dry distillation time (t)-(t ₁ + t ₃ ).

t ₃ is the time from the time when the flue temperature reaches T _min to the end of dry distillation, which is 5 to 10% of the total dry distillation time (t).
A rapid temperature rise is not preferable from the viewpoint of combustion mode of the coke oven and protection of the furnace body, so less than 5% should be avoided. On the other hand, we want to shorten this time as much as possible for tar reforming, so avoid time over 10%.

The flue temperature can be adjusted by adjusting the flow rate of the fuel gas supplied to the combustion chamber. For example, the adjusting system adjusts the flue hairpin temperature of the central flue of the coke oven combustion chamber to 10 per lump of coke oven. Point measurement,
The flow rate of the fuel gas is adjusted so that this temperature becomes the target flue temperature, and as a result, the temperature of the upper gas passage of the carbonization chamber can be adjusted.

[Example] Using a coke oven with a furnace height of 6 m and a carbonization chamber volume of 40 m ³ ,
A coke oven operation experiment was conducted. The conventional method has a flue temperature of 11
With constant heating at 00 ° C, in the method of the present invention, the flue temperature was controlled as in Case 2 and Case 3 as shown in Fig. 6. As a result, in the method of the present invention, the gas passage temperature in the upper part of the carbonization chamber was adjusted as shown in FIG. 6, and the QI in tar could be adjusted according to the target value as shown in Table 1.

On the other hand, in case 1 of the conventional method, as shown in comparison with Table 1, the QI in tar was lower than the target value, and the variation in QI was large.

 The specific adjustment method is shown below.

From the operating rate of the coke oven, the total dry distillation time of the kiln (t)
Is calculated. To obtain tar with QI = 3%, T ₁ is 1200 ℃
, Coal was charged, the temperature was raised to T _max = 1400 ° C. in 0.1 × t time, then the temperature was lowered to T _min = 800 ° C. in 0.8 × t time, and then T ₁ = T 0.1 = t in 0.1 × t time. Raise the temperature to 1200 ° C.

To obtain tar with QI = 6%, set T ₁ to 1100 ° C, raise the temperature to T _max t = 1300 ° C in 0.4t time, and then increase the temperature to T _min = 900 ° C in 0.55 x t time. Lower temperature, then increase T ₁ = 1100 ° C. in 0.05 × t hours.

To obtain tar with QI = 3-6%, for example, 4.5
% (Intermediate value of 3 to 6%), set the above setting value T ₁ to 12
Set an intermediate temperature of 1150 ° C between 00 and 1100 ° C, then 0.1 x t
˜0.4 × t time intermediate time 0.25 × t time T _max = 1400 to 1
Raise the temperature to an intermediate temperature of 1350 ° C at 300 ° C, then 0.8 ×
800 to 900 at an intermediate time of 0.675 x t hours from t to 0.55 x t hours
The intermediate temperature of ℃ is lowered to 850 ℃, then 0.05 × t
Increasing the temperature to T ₁ can be achieved with an intermediate time of 0.075 × t hours of ˜0.1 × t hours.

[Advantages of the Invention] By adjusting the flue temperature of the coke oven combustion chamber according to the present invention, it becomes possible to stably adjust the QI value in the tar generated in the coke oven, and when a raw material for an artificial graphite electrode is required. Is a coke oven operation method that yields tar with a high QI value, and a coke oven operation method that obtains tar with a low QI value is possible when raw materials such as impregnated pitch, needle coke, and carbon fiber are required. It has a remarkable effect.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between carbonization time and flue temperature of the present invention, FIG. 2 is a diagram showing the effects of secondary decomposition temperature and secondary decomposition time on QI in tar, and FIG. 3 is tar generation in the carbonization process. FIG. 4 is a diagram showing the behavior, FIG. 4 is a diagram showing changes in tar properties during the carbonization process, FIG. 5 is a diagram showing a relationship between the flue temperature and the upper gas passage temperature of the carbonization chamber, and FIG. 6 is an example of adjusting the flue temperature of the present invention. FIG.

Claims (1)

(57) [Claims] 1. In the operation of a coke oven, when adjusting the flue temperature of the combustion chamber, the flue temperature is raised to T ₁ and then coal is charged, and the flue temperature is set to the total dry distillation time (t). Heat up to T _{max in} 10-40% time, then
The temperature is lowered to T _{min in} t ₂ hours, and then 5 to the total dry distillation time
Coke oven operating method characterized by adjusting the quinoline insoluble content in tar by raising the temperature to the initial condition T ₁ at 10% time, where t: total carbonization time (hr) t ₁ : t 10-40% of the time _{(hr) t 2: t- (} t 1 + t 3) (hr) t 3: 5~10% of the time _{t (hr) T 1: 1000~1200} ℃ T max: 1400~1300 ℃ T _min : 900 ~ 800 ℃