JPS6313469B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is based on the 300 to 800
℃ carbonized coal gas is conveyed by alternately using two lines of conduits, and deposits formed on the inner surface of the conduits for conveying the gas can be removed without stopping the conveyance of the gas. This invention relates to a carbonization gas conveying device.

Coal carbonization furnace, that is, a fixed bed for the purpose of producing raw material gas for synthesis, industrial fuel gas, city gas, or coke for steel manufacturing by applying external heating, internal heating, or a combination of both to coal. Coal carbonization gas generated from furnaces of types such as , moving bed, and fluidized bed usually contains hydrocarbons such as methane and ethylene, hydrogen, water, as well as tar, crude light oil, ammonia, pyrolytic carbon, coal powder, etc. I'm here.

Such coal carbonization gas has a temperature of 500℃
In the above case, some of the hydrocarbons in the gas undergo thermal decomposition to become carbon, and this carbon adheres and grows on the furnace wall and the inner surface of the gas pipe. When the temperature of the gas is 500 to 300°C, the tar contained in the gas actively condenses and thermally decomposes, and this tar adheres to the inner surface of the gas pipe and rapidly grows.

If such deposits are left untreated,
The pressure loss of the gas flowing through the gas pipe increases, and eventually the pipe becomes clogged, making it impossible to operate. Conventionally, in order to prevent such troubles, a water sprinkling device was installed at the outlet of the coal carbonization furnace, or at the cyclone outlet if a cyclone was connected to the coal carbonization furnace, and the coal carbonization gas was sprinkled with water for 100 minutes. In addition to cooling the pipe to a temperature below 0.0°C, the condensate contained in the gas is washed away, thereby preventing deposits from growing on the inner surface of the pipe.

However, according to this method, the sensible heat retained in the carbonized coal gas is not recovered but is discarded.

On the other hand, in recent years, research has been conducted into methods of recovering sensible heat from coal carbonization gas generated from coal carbonization furnaces and making it useful for energy conservation, and for example, the following methods have been proposed.

(1) A fluidized bed or spouted bed with a built-in heat transfer tube is installed, and this is connected to a coal carbonization furnace through a conduit, and coal carbonization gas is introduced into the fluidized bed or spouted bed and into the heat transfer tube. A method of supplying boiler water and generating steam using the heat retained in carbonized coal gas.

(2) Install a spray tower, connect this and a coal carbonization furnace with a conduit, introduce the coal carbonization gas into the spray tower, cool it with tar spray, condense the tar vapor in the gas, and further This method involves separating this liquid tar from the gas and then generating steam through indirect heat exchange with boiler water.

(3) A method that combines (1) and (2) above.

(4) Install a gasifier, connect this to a coal carbonization furnace with a conduit, introduce coal carbonization gas into the gasification furnace, and supply oxygen to partially oxidize the coal carbonization gas and monoxide it. A method of metamorphosing a high-temperature reducing gas whose main components are carbon and hydrogen, and using this reducing gas to reduce iron ore pellets.

(5) installing a coal preheater, connecting this and a coal carbonization furnace with a conduit, introducing coal carbonization gas into the coal preheater and supplying coal for carbonization to dry and preheat the coal; A method for reducing the amount of heat consumed in a coal carbonization furnace.

According to the above-mentioned method, the sensible heat of the coal carbonization gas can be recovered, but the above-mentioned deposits adhere to the inner surface of the gas pipe that connects the coal carbonization furnace and the coal carbonization gas utilization equipment. However, there is a problem in that it becomes a hindrance to operations.

In order to solve this problem, high-temperature gas at a temperature of 500 to 700 degrees Celsius with an oxygen concentration of 5 to 10% is blown into the conduit where the deposits have accumulated to prevent local heating. A so-called decoking process may be performed in which the deposits are combusted while controlling the oxygen concentration and gas temperature, and the deposits are taken out of the system as combustion gas along with the unburned components separated by spalling.

However, in order to perform such a decoking process, it is necessary to stop the flow of coal carbonization gas in the gas pipe, and the operation of the above-mentioned coal carbonization gas utilization apparatus is interrupted.

Therefore, two systems of gas pipes were installed, and coal carbonization gas was passed through one of the pipes, and the other system was used as a backup. Continuous operation is possible by switching the flow of gas, flowing gas into the spare conduit, and decoking the conduit where deposits have formed.

However, in this case, since the gas conduit in the backup system is at room temperature, it is necessary to heat the conduit to a predetermined temperature before flowing gas therethrough. Therefore, it takes a lot of time to raise the temperature, so even if there is an urgent need to switch the gas flow, it cannot be handled, and there is a disadvantage that a lot of heat is consumed to raise the temperature. Another problem is that a large space is required to install two systems of gas pipes.

From the above-mentioned viewpoint, the present invention makes it possible to switch and use the backup system gas pipe at any time without requiring any special heating means when two systems of gas pipes are used to flow gas alternately. This system maintains the condition and removes deposits that occur on the inner surface of the pipe while conveying coal carbonized gas.
The present invention provides a method for conveying carbonized coal gas that can be carried out without stopping the conveyance of the gas, in which a conduit for conveying carbonized coal gas generated from a coal carbonized furnace is made of a material with good thermal conductivity. It is composed of a double pipe consisting of an inner pipe and an outer pipe made of a material with good heat insulation properties, and the pipe and the gas discharge pipe of the coal carbonization furnace are connected separately to the inner pipe and the outer pipe. , a disconnection device is provided at each of the connections, and
A decoking gas supply pipe is provided in each of the connecting portions of the inner pipe and the outer pipe, and coal carbonization gas is introduced into either the inner pipe or the outer pipe to transport the gas, and the transported gas The other of the inner tube or the outer tube is heated to maintain a state where gas can be conveyed at all times, and the deposits accumulated on the inner surface of the inner tube or the outer tube due to the conveyance of coal carbonization gas are removed. It is characterized in that the decoking gas from the supply pipe is used to burn and remove the decoking gas.

Next, the present invention will be explained with reference to examples and drawings.

FIG. 1 shows a schematic cross-sectional view of an example of the device of the present invention. In the drawing, 1 is a coke oven, 2 is a riser pipe which is a discharge pipe for carbonized coal gas,
3 is the same bent pipe, 4 is the top cover, and the bent pipe 3 has short pipes 5, 5' for guiding coal carbonization gas to the conduit.
The branch portions of the short pipes 5, 5' in the curved pipe 3 are provided with liquid seal cutoff devices 6, 6' using tin as a sealing liquid for opening and closing the branch portions.

The gas conduit A has a double pipe structure consisting of an inner pipe 7 and an outer pipe 8 provided outside the inner pipe 7 and concentric with the inner pipe 7, and the cross-sectional area of the inner pipe 7 and the outer pipe 8 are The cross-sectional area between the inner tube 7 and the inner tube 7 is approximately equal. The short tube 5 is connected to the inner tube 7, and the short tube 5' is connected to the outer tube 8.

At the end of the gas conduit A, as shown in FIG. 2, the outer tube 8 has a conduit 9 leading to a coal carbonization gas utilization device (not shown), and the inner tube 7 has a conduit 9 leading to another coal carbonization gas utilization device. 10 are connected. Gate valves 11 and 11' are provided in the middle of the conduit 9, and gate valves 12 and 12' are provided in the middle of the conduit 10. 13 is a decoking gas supply pipe provided in the short pipe 5, and 13' is a decoking gas supply pipe provided in the short pipe 5';
4' is an inert gas supply pipe for introducing inert gas into the inner tube 7 or outer tube 8 when not in use.

Note that the inner tube 7 is made of a material with good thermal conductivity, and the outer tube 8 is made of a material with good heat insulation properties.

In the above-described configuration, an example in which carbonized coal gas is passed through the inner pipe 7 of the gas conduit A and the outer pipe 8 is in a state after decoking is shown in FIGS. 1 and 2.

Opening the shutoff device 6 leading to the inner pipe 7 and the gate valves 12, 12' of the conduit 10 connected to the inner pipe 7;
On the other hand, by closing the shutoff device 6' leading to the outer pipe 8 and the gate valves 11, 11' of the conduit 9 connected to the outer pipe 8, the carbonized coal gas generated from the coke oven 1 is discharged through the gas discharge pipe. It is led to an inner pipe 7 of the gas conduit A through a riser pipe 2, a bent pipe 3, and a short pipe 5, and is sent to a coal carbonization gas utilization device (not shown) through the inner pipe 7 and the conduit 10.

At this time, the heat of the gas flowing inside the inner tube 7 is transferred to the outer tube 8, heating the tube body of the outer tube 8 and the inert gas stagnant inside the outer tube 8, so that the outer tube 8 is transferred to the inner tube 8. By switching between the two, you can keep it available for use at any time.

As a result of conveying the carbonized coal gas through the inner pipe 7 in this way, when deposits accumulate on the inner surface of the inner pipe 7, the shutoff device 6 and the gate valves 12, 1
2' is closed, and on the other hand, the shutoff device 6' and the gate valves 11, 11' are opened, so that the coal carbonization gas generated from the coke oven 1 is transferred to the riser pipe 2, the bent pipe 3 and the short pipe 5. ′, lead to the outer tube 8,
The outer pipe 8 and conduit 9 transport the coal to another coal carbonization gas utilization device (not shown).

On the other hand, the gate valves 12 and 12' of the inner pipe 7 were opened, and the oxygen concentration in the inner pipe 7 from the supply pipe 13 was 5 to 10.
%, and decoking gas at a temperature of 500 to 700° C. is blown into the tube, and the deposits on the inner tube 7 are burned off and removed by this gas. The decoking gas from which deposits have been burned off in this way is sent to the coal carbonization gas utilization device, and is also used for decoking in this device if necessary.

Thus, the decoked inner tube 7 is heated as described above by the high-temperature carbonized coal gas flowing inside the outer tube 8, and is kept ready for use at any time. As a result, the gas flow between the inner tube 7 and the outer tube 8 can be switched whenever necessary. Although not shown, a conduit 9 and a conduit 10 leading to the coal carbonization gas utilization device
It is also desirable that the tube be constructed of a double tube consisting of the above-mentioned inner tube and outer tube.

Furthermore, according to this method, since the two systems of gas conduits are composed of an inner tube and an outer tube, there is an advantage that the space for installing the gas conduits is also small.

As described above, according to the present invention, when two systems of gas pipes are used to alternately flow gas, the backup system gas pipe can be switched and used at any time without requiring any special heating means. This system maintains the condition and removes deposits that occur on the inner surface of the pipe while conveying coal carbonized gas.
Industrially excellent effects such as being able to carry out the transport of the gas without stopping are brought about.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an example of the apparatus of the present invention, and FIG. 2 is a schematic sectional view showing the end portion of the gas conduit. In the drawings, 1...Coke oven, 2...Rising pipe, 3...Bent pipe, 4...Top cover, 5, 5'...Short pipe, 6,
6'...Shutoff device, A...Gas conduit, 7...Inner pipe,
8... Outer tube, 9, 10... Conduit, 11, 11',
12, 12'... Gate valve, 13, 13'... Supply pipe, 14, 14''... Inert gas supply pipe.

Claims (1)

[Claims] 1. A conduit for transporting coal carbonization gas generated from a coal carbonization furnace is constructed with a double pipe consisting of an inner pipe made of a material with good thermal conductivity and an outer pipe made of a material with good heat insulation properties, The conduit and the gas discharge pipe of the coal carbonization furnace are connected separately into the inner pipe and the outer pipe, and each of the connecting parts is provided with a shutoff device, and each of the connecting parts of the inner pipe and the outer pipe is connected. A decoking gas supply pipe is provided in the inner pipe or the outer pipe, and coal carbonization gas is introduced into either the inner pipe or the outer pipe to transport the gas, and the transported gas causes the other of the inner pipe or the outer pipe to be transported. is heated and kept in a state where gas can be conveyed at all times, and the deposits accumulated on the inner surface of the inner tube or outer tube due to conveyance of coal carbonization gas are burned off by decoking gas from the supply tube. A coal carbonization gas conveying device characterized by: