JPS61207487A - Method of recovering gas generated in coke oven - Google Patents

Abstract

PURPOSE:To effectively utilize a gas generated from a chamber coke oven, by recovering a gas having a high calorific value generated in the first half of carbonization and a gas having a high hydrogen concentration generated in the second half of carbonization using different recovering systems by conducting the changeover of the recovering system in recovering a gas generated in a chamber coke oven. CONSTITUTION:A gas having a high calorific value generated in the first half of carbonization from a carbonization chamber 1 of a chamber coke oven is introduced into tar traps 5, 6 where the gas is sprayed with an ammonia liquor to cool it. The cooled gas is recovered with a pump 9 and used as a fuel etc. A gas having a high hydrogen concentration generated in the second half of carbonization is introduced into another recovering system by operating a passage changeover damper 10 and a passage changeover valve 11. The gas is recovered without spray of the ammonia liquor to efficiently recover a high sensible heat which is effectively used as a hydrogen source. It is preferred that the changeover of the recovering system is conducted when the temperature of the carbonization chamber 1 at its central portion 3 reaches 450 deg.C or higher or when the hydrogen concentration of the generated gas reaches 60vol.% or higher.

Description

[Detailed description of the invention] [Industrial application field] The present invention is for use in metallurgy in a chamber furnace type coke oven.

The present invention relates to a method for recovering gas generated from a carbonization chamber when producing coke for fuel, etc.

[Prior art]

The gas generated from the carbonization chamber in a chamber coke oven is
It passes through a riser pipe installed in each carbonization chamber and is led to a collecting main installed in one furnace group or multiple furnace groups, and is collected all at once from the start of carbonization to the end of the fire in each carbonization chamber. .

When recovering this gas, since there is highly concentrated tar vapor in the generated gas, ammonium water is sprayed at the bend of the riser pipe to cool the generated gas, which condenses and separates the tar before releasing the gas. It is common to collect them.

[Problem that the invention seeks to solve]

According to the conventional recovery method described above, the generated gas is usually at a high temperature of 700°C to 800°C, but the generated gas is unnecessarily cooled by spraying with cheap water even in areas that do not need it. Or, if we try to recover this high sensible heat before spraying the ammonium water, it will be necessary to install a special heat exchanger for each riser pipe, which is extremely uneconomical and will cause the temperature to rise above the condensation temperature of the tar. Since this method requires operations, it has the disadvantage that such high sensible heat cannot be sufficiently recovered, resulting in inefficiency. Further, the composition of the generated gas changes as the carbonization progresses, and the concentration of hydrogen, which has a low calorific value, is particularly high at the end of the carbonization, and therefore the calorific value of the entire generated gas decreases. Moreover, a coke oven consists of a furnace group with a large number of furnace chambers arranged, and carbonization in the second furnace chamber starts at an arbitrary time after the start of carbonization in the first furnace chamber. Carbonization is carried out in the furnace chambers at different times. Therefore, in the conventional bulk recovery method, gases generated from a large number of furnace chambers having different elapsed times from the start of carbonization are recovered at the same time. In other words, generated gases with different compositions are collected at the same time.For example, gases that contain a large amount of hydrogen gas, which has a low calorific value as mentioned above, and gases generated during the first half of carbonization, which have a high calorific value, are also collected in a state where the calorific value is reduced. It will be collected. On the other hand, industrially useful hydrogen gas cannot be used because it is recovered at the same time as the gas produced in the first half of carbonization, which is low in hydrogen gas.

[Means for solving problems]

The present invention solves the problems of the conventional method by recovering the gas generated in the first half of carbonization and the gas generated in the second half of carbonization using different recovery systems. be.

As a result of a detailed study of the progress of carbonization in the carbonization chamber and changes in the composition of the generated gas, the inventors of the present invention found that by applying a recovery method that corresponds to the change in the composition of the generated gas, a high value-added state can be obtained. It has been found that the generated gas can be recovered and can be used effectively depending on the composition of the generated gas. The present invention was completed based on such knowledge.

FIG. 1 is a graph based on the results of research conducted by the inventors of the present invention.

Among these figures, FIG. 1(A) is a diagram showing the relationship between the carbonization elapsed time and the temperature at the center of the carbonization chamber during carbonization. Further, FIG. 1(B) is a diagram showing the relationship between the carbonization elapsed time and the amount of generated gas.

As is clear from FIG. 1(B), changes in the composition of the generated gas can be roughly divided into two types. That is, it is divided into the first half of carbonization shown in section I in the drawing and the second half of carbonization shown in section ■. Among these categories, in Category I, the calorific value of the generated gas is 5000K ca, excluding the short period at the beginning of carbonization.
t/Nn+" or more, the concentration of H2 is 50 to 55% by volume, and the concentration of CH4 is 30 to 35% by volume, which remains stable as if it were a dead wall.Although the tar content gradually decreases, it remains in the generated gas. Existing.

On the other hand, in category (2), H2 increases significantly and rapidly from 55% by volume to 90% by volume, and CH4 significantly decreases. Since CH4, which has a high calorific value, is reduced in this way, the calorific value of the generated gas is significantly reduced. In addition, almost no tar is present in the generated gas in category ①.

As described above, based on research results, tar is present in the first half of carbonization, so the conventional recovery method of spraying ammonium water at the V section of the riser pen is effective.

On the other hand, in the second half of carbonization, there is almost no tar content, so there is no need to spray ammonium water.

Therefore, it is possible to recover the generated gas with a high hydrogen concentration without cooling it if it is recovered using a separate recovery system different from the recovery system for the generated gas in the first half of carbonization. From the above, the invention of the present invention As mentioned above, these authors have invented a method for recovering gas generated in which the recovery of gas generated in the first half of carbonization is different from the recovery of gas generated in the second half of carbonization.

Next, a method for implementing the present invention will be explained.

First, in the first half of the carbonization, as in the conventional method, ammonium water is sprayed while collecting and post-processing is performed in the first collecting main. Then, in the second half of the carbonization, a second collecting main is installed and connected to the carbonization chamber through a suitable connecting pipe, through which the waste is collected and post-processed. The method of installing the second collecting main used in this case and the connecting pipes with each carbonization chamber does not require any special limitations. It may be determined arbitrarily, taking into account the utilization form of hydrogen-rich gas, etc.

Next, regarding the setting of the switching timing of the recovery system between the first half of carbonization and the second half of carbonization, the following points (a) to (d) can be considered, for example.

(a) A method in which the switching time is empirically and statistically preset based on the fire-off time determined by the carbonization temperature, for example, 4 hours before the fire-off time.

(b) The switching time is determined when the temperature at the center of the carbonization chamber reaches 450°C or higher, preferably 500°C or higher.

(C) Continuously measure the tar concentration and amount of generated gas, and set the time for switching when tar is no longer observed.

(d) The composition of the generated gas is continuously measured, and the switching point is defined as the point in time when the concentration of H2 becomes, for example, 60% by volume or more, preferably 65% by volume or more.

In addition to the above, the switching timing can also be set using at least two of (a) to (d), that is, an arbitrary combination of a plurality of them. This combination of a plurality of items enables more accurate collection.

Furthermore, it is clear from FIG. 1 that the switching timing can be set based on changes in the concentration of H2, OH4, etc., changes in the temperature of the generated gas, etc.

Among the generated gases recovered by the above method, the generated gas from the first half of carbonization is treated by conventional methods, but the gas generated from the second half of carbonization can be treated as desired depending on its usage form. .

Examples of uses of the gas generated in the second half of carbonization include gas for hydrogenolysis of coal, pitch, tar, etc., and methods for producing hydrogen gas by cryogenic separation and adsorption separation.

〔Example〕

Next, an embodiment of the generated gas recovery method of the present invention will be described. The embodiment shown here was carried out using an apparatus as shown in FIG. Therefore, first we will give an overview of the apparatus shown in Figure 2. In Figure 1, 1 is a carbonization chamber, 2 is a heating wall, 3 is a temperature measuring part that measures the temperature at the center of the charcoal chamber 1, and 4
5 and 6 are tar traps; 7 is an analyzer for the gas guided from each tar trap; 8 is a gas meter; 9 is a pump; 10 is a channel switching damper; and 11 is a channel switching valve. Note that the one shown in FIG. 2 shows one recovery system, and the other recovery systems are similarly provided by an appropriate method. The carbonization test in this example is shown in Table 1 below.
It was carried out under the conditions shown below.

Table 1 Volatile components of charged coal 30% by weight Charged coal particles 80% by weight (less than 3%) Charged coal moisture 8.5% by weight Charged coal density & 0.78 t/n? In a carbonization test conducted under the above conditions in an apparatus with a carbonization temperature of 1050°C or higher.

The temperature at the center of the carbonization chamber was 500°C (Example 1) and 60°C.
When the temperature reached 0°C (Example 2), the generated gas flow path was switched by operating the damper ~ 10 and valve 11, and the generated amount 9 composition and calorific value were measured for the generated gas in the first half of carbonization and the second half of carbonization. is as shown in Table 2.

As a comparative example, a similar measurement was performed without operating the damper (without switching the flow path) and is also listed in Table 2.

Table 2 [Effects of the Invention] According to the generated gas recovery method of the present invention, the generated gas recovered in the first half of carbonization has a higher concentration than the generated gas (containing a large amount of hydrogen gas) recovered all at once by the conventional method. A gas with a calorific value of 5000 Kcat/Nrrl can be obtained.

In addition, high hydrogen concentration gas can be obtained from the latter half of carbonization. Therefore, effective use can be made in either case. Particularly in the latter half of carbonization, high sensible heat can be efficiently recovered because it can be recovered without cooling and it does not contain tar, and it can be effectively used as an industrially useful hydrogen source.

[Brief explanation of drawings]

Figure 1 shows the relationship between elapsed carbonization time, temperature at the center of the carbonization chamber, calorific value, and composition of generated gas. Figure 2 shows the carbonization equipment used in the examples of the present invention and the system for collecting and measuring generated gas. FIG. 2 is a schematic diagram showing the configuration of. DESCRIPTION OF SYMBOLS 1... Carbonization chamber, 2... Heating chamber, 3... Carbonization chamber center temperature measuring part, 4... Rising tube, 5, 6... Tar trap, 7... Gas analyzer, 8 ...Gas meter, 9...
・Pump, 10...Flow path switching damper, 11...
Flow path switching valve. Applicant: Hiroshi Mukai, agent for Mitsubishi Chemical Industries, Ltd. - Currently announcing the establishment of a chemical industry (161 East) - Mitsubishi Kasei C)

Claims (5)

[Claims] (1) A method for recovering gas generated from a coke oven carbonization chamber, characterized in that the gas generated during the first half of carbonization and the gas generated during the second half of carbonization are selectively recovered using different recovery systems. A method for recovering generated gas from a coke oven. (2) The timing at which the gas generated during the second half of carbonization is switched to a recovery system different from the recovery system for the gas generated during the first half of carbonization is when the temperature at the center of the carbonization chamber reaches 450°C or higher. A method for recovering generated gas from a coke oven according to claim (1). (3) The timing at which the gas generated in the second half of the carbonization is switched to a recovery system different from the recovery system for the gas generated in the first half of the carbonization is the point at which the hydrogen concentration in the gas generated reaches 60% by volume or more. A method for recovering generated gas from a coke oven according to claim (1). (4) A patent claim characterized in that the timing at which the gas generated in the second half of the carbonization is switched to a recovery system different from the recovery system for the gas generated in the first half of the carbonization is at least 4 hours before the fire-off time. A method for recovering generated gas from a coke oven according to scope (1). (5) The time when the gas generated in the second half of carbonization is switched to a recovery system different from the recovery system for the gas generated in the first half of carbonization is when the temperature in the center of the carbonization chamber reaches 450°C or higher, and the hydrogen concentration in the gas generated is The generation from the coke oven according to claim (1), characterized in that the occurrence is at least two points in time: the point in time where the Gas recovery method.