JPS6350632B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering sensible heat of coke oven crude gas generated in a coke oven carbonization chamber, and in particular to a method for preventing the occurrence of coking and stably operating a heat exchange device for a long period of time. The present invention relates to a method for recovering heat from the gas described above.

Conventionally, the temperature of 600 to 800℃ generated in the coke oven carbonization chamber
The crude gas generated in the coke oven is cooled to around 85℃ by ammonium water flushing, and then sucked and pumped to the gas purification process, and the sensible heat of this gas is not used effectively.

In order to utilize the sensible heat of this gas, when the gas is directly led to a heat exchanger for heat exchange, the following problems occur with a normal heat exchanger, and it is not possible to operate stably for a long period of time.

In other words, the crude gas generated from a coke oven contains large amounts of high-boiling substances such as benzoles and tar, moisture, and other soluble impurities, and benzole and tar decompose at high temperatures in an environment of 450°C or higher. Carbon is deposited on the heat transfer tubes, and high boiling point substances such as tar condense on the heat transfer tubes in environments below 450℃. As a result, gas pipes and heat exchangers are blocked, so-called coking occurs, pressure loss increases, and heat exchange efficiency decreases, making it impossible to operate the equipment stably for a long period of time.

Therefore, the inventors of the present invention have conducted research to recover and effectively utilize the sensible heat of the crude gas generated in coke ovens, which had not been used in the past, by preventing the occurrence of coking and by operating the heat exchanger in a long-term stable manner. established a technology for heat recovery using a spouted bed cooler and a wet wall cooler, and filed a patent application as Patent Application No. 111196/1982, but later research revealed that heat recovery could be effectively achieved using a tar cooler alone. Thus, the present invention was achieved.

That is, the present invention relates to a heat recovery method for coke oven generated crude gas, which is characterized in that the coke oven generated crude gas is once collected in an air collecting pipe and then the sensible heat of the gas is recovered using only a heat exchanger using a tar cooler. It is.

Hereinafter, the method of the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 is a flowchart showing an example of an embodiment of the method of the present invention.

In FIG. 1, two gas pipes 3 and 4 are provided in a riser pipe 2 connected to a carbonization chamber of a coke oven 1, and the gas pipe 3 includes a shutoff valve 5, an air collection pipe 6, a tar cooler 7, and an ammonium water cooler 8. , a flow rate control device 9, and a gas blower 10 are provided in this order, and the other end of the pipe line 3 is connected to a dry main 12. The other gas pipe line 4 includes a water seal valve 11, a dry main 12, a pressure control device 13,
A primary cooler 14, a pressure control device 15, and a gas blower 16 are provided in this order, and the end of the pipe line 4 is connected to a gas purification device (not shown).

The tar cooler 7 described above has a configuration as shown in FIG. 2. That is, a gas-liquid contact chamber 2 equipped with a gas inlet 19 is provided inside the outer cylinder 18.
A gas-liquid separation chamber 22 having a gas outlet 1 and a gas outlet 20 is provided, and between these two chambers 21 and 22, a flow-through conduit 25 for circulating oil for heat exchange such as self-byproduct tar or medium oil with high solubility is connected to a tube plate. 23 and 24, the tube plate 2
The space between 3 and 24 is used as a water chamber 31 for heat exchange. Outer cylinder 18
A circulation pump 26 and a pipe line 27 are provided outside of the gas-liquid separation chamber 22 to return oil to the gas-liquid contact chamber 21, and a pump 32 and pipe lines 33, 34, 35 for circulating heat exchange water are provided. A steam-water separator 30 is provided, and a replenishment pump 37 and a pipe line 38 for replenishing the steam-water separator 30 with water for heat exchange are also provided. A temperature sensor 39 for controlling the gas temperature at the gas outlet 20 and a level meter 29 for controlling the liquid level in the gas-liquid separation chamber 22 are provided, and a pipe line 40 branching from the pipe line 27 is provided with A control valve 28 is provided.

In the flow configured as described above, the coke oven generated crude gas enters the tar cooler 7 via the shutoff valve 5 and the air collection pipe 6. In the tar cooler 7, the gas enters the gas-liquid contact chamber 21 from the gas inlet 19, passes through the downstream pipe 25, passes through the gas-liquid separation chamber 22, and exits from the gas outlet 20. On the other hand, circulating oil
The liquid flows down from the gas-liquid contact chamber 21 through the downstream pipe 25 while forming a liquid film, accumulates in the gas-liquid separation chamber 22, and is returned to the gas-liquid contact chamber 21 by the action of the pump 26. Due to the above-mentioned gas flow and circulation of the circulating oil, the heat of the crude gas generated in the coke oven is transferred from the liquid film of the circulating oil to the heat exchange water flowing through the heat exchange water chamber 31, and the steam is separated in the steam separator 30. heat is recovered.

Further, the gas temperature at the gas outlet 20 is detected by a temperature sensor 39, and the overflow position of the heat exchange water (that is, the pipe line 34 or the pipe line 35) is adjusted by the control valve 36. The thermal area is increased or decreased, thereby maintaining the gas temperature at the gas outlet 20 constant (200-300°C). The level of the circulating oil in the gas-liquid separation chamber 22 is detected by a level meter 29, and when the level rises, the control valve 28 is opened and the circulating oil is sent outside through a pipe 40 branching from the circulating oil circulation pipe 27. Extract and adjust the level.

As mentioned above, heat is recovered in tar cooler 7.
The coke oven gas, which has reached a temperature of about 200 to 300 degrees Celsius, is led to the ammonium water cooler 8, where the temperature is lowered to 70 to 80 degrees Celsius by the ammonium water injected from the pipe line 8, and then a flow rate control device 9 is installed. The gas enters the dry main 12 through a blower 10 for pressure compensation, and then is sent to a gas purification process through a pipe 4, a primary cooler 14, and a blower 16.

Further, it is preferable that the water seal valve 11 is opened together with the cutoff valve 5, and the pressure is controlled using a pressure control device 13 provided in the gas pipe line 4 so that a predetermined amount of gas flows into the gas pipe line 3, This allows stable pressure control and gas suction to be performed.

FIG. 3 is a flowchart showing another embodiment of the method of the present invention. In FIG. 3, the same reference numerals as in FIGS. 1 and 2 indicate items with the same functions as in FIGS. 1 and 2.

The flow shown in FIG. 3 is such that the gas pipe 3 is equipped with a shutoff valve 5, an air collection pipe 6, a pressure control device 17, a tar cooler 7, an ammonium water cooler 8, a primary cooler 14, a pressure control device 15, and a gas blower 16. The gas pipe 4 is provided with a water seal valve 11, a dry main 12, and a pressure control device 13, and the end of the gas pipe 4 is connected between the ammonium water cooler 8 and the primary cooler 14.

In FIG. 3, even if gas is not passed to the drain main 12 side, the drain main 12 is always flushed with mild water to prevent temperature drop and to prevent malfunctions.
It is preferable to be able to switch immediately even when the operation is stopped for inspection or the like. (In addition,
The temperature drop in the dry main 12 is prevented because the dry main is fixed to the coke oven main body, and there is a risk of distortion due to thermal expansion if the dry main is subjected to temperature changes, so this is to be prevented. ) The flow shown in FIG. 1 is suitable for applying the method of the present invention to an existing coke oven because the gas pipe line 4 and each equipment installed in the pipe line 4 are the same as conventional equipment. The flow shown in FIG. 3 omits the gas blower 10 in the flow shown in FIG. 1, and is suitable for applying the method of the present invention to a newly installed coke oven.

The effects of the method of the present invention explained above are summarized as follows.

(1) Even if tar, pitch, etc. in the gas condenses in a tar cooler, it can be washed and dissolved with a large amount of circulating oil, preventing coking and improving its heat transfer performance. There are also fewer losses.

(2) In the tar cooler, the self-byproduct tar circulating in the cooler has high thermal stability (the decomposition temperature of tar is above 300 to 400°C), and medium pressure steam of about 60 kg/cm ² G can be recovered.

(3) Since tar coolers can recover heat while preventing coking, they can operate stably and continuously for long periods of time.

(4) Compared to the previously-mentioned patent application (Japanese Patent Application No. 111196/1982), (i) the overall pressure loss can be reduced to less than 1/2, and the electricity cost of the gas blower can be reduced; (ii) the tar cooler can be reduced. The cooling capacity is high, and the entire device can be made more compact.

(5) In a tar cooler, the outlet gas temperature and the circulating oil (tar) temperature are almost equal, so the gas cooling temperature is determined by the properties of the circulating oil (tar) (according to experiments, below 200°C, tar The viscosity increases rapidly and thermal transformation of tar begins above 300℃, so the tar temperature that can be stably handled is 200 to 300℃.Therefore, the tar cooler outlet gas temperature ((gas cooling temperature)) is 200
The temperature should be adjusted to ~300℃. )

[Brief explanation of the drawing]

1 and 3 are flowcharts showing one embodiment of the method of the present invention, and FIG. 2 is a diagram showing the configuration of a tar cooler used in the method of the present invention.

Claims (1)

[Claims] 1. A method for recovering heat from coke oven crude gas, which comprises once collecting coke oven crude gas in a gas collection pipe, and then recovering the sensible heat of the gas using only a heat exchanger using a tar cooler.