JPH0140872B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for recovering sensible heat from red-hot coke in a grate dry fire extinguishing method using an inert gas. There are various methods of recovering heat from the high-temperature gas obtained by heat exchange between red-hot coke and inert gas in the dry fire extinguishing method.One of them is a method of using it for drying and preheating coal, as shown in Japanese Patent Publication No. 44-28380. There is. The method shown in Japanese Patent Publication No. 44-28380 (dry extinguishing method for coke) is conceptually shown in Figure 1, in which red-hot coke 2 from a coke oven (not shown) is loaded into a dry extinguisher 1 in batches. and discharged as cold coke 3. During this time, the inert gas introduced into the dry fire extinguisher 1 exchanges heat with the red-hot coke,
The high-temperature gas is directly sent to the coal dryer 4, enters through the coal supply port 5, and dries and preheats the raw coal that is discharged from the coal discharge port. The inert gas discharged from the coal dryer 4 is further cooled, dehumidified, and dust removed by a gas-liquid contactor 7, and introduced into the dry fire extinguisher 1 for circulation use. That is, this is a method in which high-temperature inert gas obtained by sensible heat recovery from red-hot coke is directly used to dry or preheat raw coal. However, this method has the following defects and is extremely disadvantageous in practice. (1) For example, when drying coal in a fluidized bed, in order to dry efficiently below the thermal decomposition temperature of coal (350°C) without deteriorating coking properties, A gas temperature of approximately 350°C is required. However, since the temperature of the inert gas derived from a dry fire extinguisher is usually about 800°C, it is not preferable to introduce it directly into a coal dryer. For this reason, for example, even if low-temperature inert gas is mixed with high-temperature inert gas to adjust the temperature, the amount of inert gas for dilution will be large, and the power and equipment costs required for circulation will increase, making it economical. This would be extremely disadvantageous. (2) Furthermore, although it depends on the degree of dehumidification, the amount of heat required to dry coal is approximately 30% of the amount of heat held by high-temperature inert gas, which creates a large amount of surplus heat, which is not only uneconomical, but also This has the disadvantage of collecting unused gas that still has usable sensible heat, and requiring a large amount of cooling water for circulation and use in the dry fire extinguisher. (3) Red-hot coke is supplied to the dry fire extinguisher in batches to extinguish the fire.
At the end of the extinguishing process, there is a disadvantage that the hot gas supplied to the coal dryer must be heated using auxiliary fuel. To address these drawbacks of the conventional method, an improved method is to introduce inert gas from a dry fire extinguisher into a waste heat boiler, recover the heat, adjust it to below the thermal decomposition temperature of coal, and send it to a coal dryer. Disclosed in Japanese Patent Publication No. 56-14578, this method: (1) Since a boiler whose heat transfer area is difficult to change during operation is inserted in series in the hot gas system, the coal dryer side It is not easy to adjust the coal dryer inlet gas temperature level to meet changing demands. (2) Two or more types of inert gases with different temperature levels cannot be obtained. (3) Since the entire system is connected in series, it is not possible to change the balance, for example, by changing the flow rate of inert gas, based on the requirements of only one device. There are drawbacks such as. The present invention has been developed as a result of intensive research aimed at solving the drawbacks of the above-mentioned conventional methods and developing a method that can effectively utilize the sensible heat of coke for drying coal. When used, the temperature of the inert gas used for coal drying is 300 to 350°C, but this temperature is due to the heat exchange between the inert gas passing through the second half of the dry fire extinguisher and the hot coke in the second half of the extinguishing process. Furthermore, the large amount of heat remaining after subtracting the heat required for drying the coal from the coke sensible heat is obtained by heat exchange between the red-hot coke in the first half of the extinguishing process and the inert gas passing through the first half. The inventors have discovered that a waste heat boiler suitable for utilizing heat from high-temperature gas can be used to recover this heat, and based on this knowledge, the present invention has been completed. That is, in the grate dry extinguishing method for coke using an inert gas, the present invention allows the inert gas to pass through an inert gas passage in a dry extinguisher that is divided into a plurality of sections in the direction of movement of the grate by a sealing partition plate. The inert gas in the high-temperature section is extracted after being divided into at least two systems, a high-temperature section and a medium-temperature section, and the inert gas in the medium-temperature section is used for a heated object processing device. This paper proposes a heat recovery method in the coke dry extinguishing method, which is characterized by circulating the heat to the dry extinguisher. In addition, the present invention divides the inert gas passing through the inert gas passage in the dry fire extinguisher into two systems, a high temperature section and a medium temperature section, and extracts the inert gas, and the inert gas in the high temperature section is heat recovered by a waste heat boiler. By using the inert gas in the medium temperature section in the coal dryer, the inert gas at the temperature suitable for each is sent from the dry fire extinguisher to the waste heat boiler and the coal dryer, which have different required gas temperature conditions. , proposes a heat recovery method for coke dry fire extinguishing method, which is characterized by direct introduction without pretreatment and parallel use of waste heat boiler and coal dryer in an inert gas system divided into two systems. It is. Further, in the present invention, the inert gas passing through the inert gas passage in the dry fire extinguisher is divided into two systems, a high temperature part and a medium temperature part, and the inert gas in the high temperature part is recovered as heat by a waste heat boiler. After that, it is circulated and supplied to the dry fire extinguisher, and the inert gas taken out from the medium temperature section is directly sent to the coal dryer to dry the raw coal, and then it is dedusted and dehumidified, and then circulated and supplied to the dry fire extinguisher. Therefore, we propose a heat recovery method in the coke dry extinguishing method, which is characterized by the circulation and use of inert gas in two independent systems. Next, embodiments of the present invention will be described with reference to the drawings. FIG. 2 is an explanatory diagram of an example of an embodiment of the present invention. In FIG. 2, red-hot coke 2 from a coke oven (not shown) is supplied into a circular grate dry extinguisher 1, extinguished after exchanging heat with low-temperature inert gas, and discharged as cold coke 3.
The main components of the inert gas are nitrogen, carbon dioxide, etc., but they also contain some hydrogen, oxygen, and moisture. Representative examples are shown in Table 1.

[Table] In the dry fire extinguisher 1, for example, an endless grate moves horizontally within an annular or linear cell (the side walls of the grate may form part of the cell), and the coke is deposited on the grate. It is loaded and transported. A partition plate 8 that constitutes an inert gas passage is installed in the cell, and the inert gas passage in the dry fire extinguisher is divided into the first chamber 9, second chamber 10, and third chamber 1 from the high temperature side.
It is divided into 1 and 4th chamber 12. The partition plate 8 forms an inert gas passage, but is installed so as to partition only an air layer that does not interfere with the movement of the grates and coke. The circulation of inert gas is divided into two systems: the coal drying system and the waste heat boiler, and the gas in the coal drying system uses coke from the medium and low temperature side. That is, the inert gas sent to the fourth chamber 12 by the blower 13 is heated by the coke in the fourth chamber 12, and further sent to the third chamber 11 by the blower 18 to a temperature suitable for the fluidized bed coal dryer 4. The heated coal is sent to the coal dryer 4 by the blower 17. In the coal dryer 4, wet coal is fed to the coal supply port 5.
The coal is supplied from the coal outlet 6, and is discharged from the coal outlet 6.
During this time, the moisture in the wet coal is evaporated by the inert gas introduced from the third chamber 11, and the coal is dried. This evaporated inert gas containing moisture is sent to the fourth chamber 12 by the blower 13, where it is removed from dust, dehumidified, and temperature controlled by the next gas-liquid contactor 7, and is used for circulation. On the other hand, in the waste heat boiler system, the second chamber 10 is
The inert gas sent to is heated by exchanging heat with the high temperature coke, and then sent to the first chamber 9 by the blower 19, where it is further heated. This heated inert gas is sent to the waste heat boiler 15, where it is cooled while generating steam.
6, the air is sent to the second chamber 10 by the blower 14, and is used for circulation. The main purpose of the gas-liquid contactor 7 is dehumidification and dust removal, but in addition to the ejector that commonly achieves both purposes, there is also a water sprinkler type, and a cyclone for dust removal.
Using a bag filter and a compressor for dehumidification,
These can be used in combination. Furthermore, the method of the present invention can be applied to the coal dryer 4 not only of the fluidized bed type but also of the moving bed type, the air flow type, and the indirect heating type. FIG. 3 shows another embodiment of the invention. In this second embodiment, the inert gas in the waste heat boiler system is combined with the inert gas in the coal drying system and returned to the dry fire extinguisher for circulation use. In addition, in the method of the present invention, the heat recovery loop is divided into three or more systems, for example, inert gas in the high temperature section is recovered by a waste heat boiler system, inert gas in the medium temperature section is recovered by a coal drying system, and low temperature section is recovered from inert gas by a coal drying system. Heat can be recovered from the inert gas in the tank using a fuel preheating system or the like. As described above in detail, the method of the present invention can provide the following effects. (1) The amount of heat held in the gas obtained by recovering the sensible heat of coke can be recovered at the same time by the waste heat boiler and the heated object processing device such as the coal dryer, so the efficiency of recovering the sensible heat of coke is improved. (2) By combining heated processing equipment such as a coal dryer with a dry fire extinguisher, the circulating gas temperature will be lowered and coke cooling efficiency will be greatly improved. (3) Since the inert gas from the dry fire extinguisher can be directly introduced into the waste heat boiler and coal dryer without pre-treatment, the equipment cost is low and economical. (4) By changing the position of the partition plate and/or the circulation position of the inert gas obtained from the high-temperature section, the temperature and/or gas amount of the inert gas obtained from the medium-temperature section or the low-temperature section can be arbitrarily changed. Can be done. That is, there is flexibility in being able to appropriately select the temperature and/or gas amount of the inert gas depending on the type and scale of the heated object processing apparatus. (5) By dedusting the coal drying system with inert gas, it is possible to eliminate problems caused by dust accumulation in the system, and by dehumidifying it, it is possible to prevent the evaporation of moisture from the wet coal in the coal dryer. can be increased. The effects of the present invention will be explained in more detail below using Examples. Example: The inert gas passing through the inert gas passage in a dry fire extinguisher is divided into two systems: a high temperature section and a medium temperature section, and the inert gas in the high temperature section is recovered by a waste heat boiler, and the inert gas in the medium temperature section is recovered. The heat recovery rate was determined when the active gas was used in a fluidized bed coal dryer. The results are shown in Table 2.

[Table] Shows the recovery rate.
According to the present invention, a heat recovery rate of 83.6% can be achieved as described above, and the purpose of the dry fire extinguishing method can be fully achieved. As described above in detail, the present invention provides a method for recovering heat in a coke dry extinguishing method, which is extremely useful industrially.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a heat recovery method in the conventional coke dry extinguishing method, Fig. 2 is an explanatory diagram of a first embodiment of the heat recovery method according to the present invention, and Fig. 3 is an explanatory diagram of the heat recovery method according to the present invention. FIG. 3 is an illustration of a second example embodiment of the method; 1... Dry fire extinguisher, 4... Fluidized bed coal dryer, 7
...gas-liquid contactor, 15...waste heat boiler.

Claims (1)

[Claims] 1. In the grate dry extinguishing method for coke using inert gas, inert gas is passed through an inert gas passage in a dry extinguisher that is divided into a plurality of sections in the direction of movement of the grate by sealing partition plates. , divide it into at least two systems, a high-temperature part and a medium-temperature part, and take it out.
The coke dry fire extinguishing method is characterized in that the inert gas in the high temperature section recovers heat in a waste heat boiler, and the inert gas in the medium temperature zone is used in a heated object processing device and then circulated to a dry fire extinguisher. heat recovery method in the law. 2 In the grate dry extinguishing method for coke using inert gas, the inert gas passing through the inert gas passage in the dry extinguisher, which is divided into multiple sections in the direction of movement of the grate by sealing partition plates, is divided into high temperature and medium temperature sections. The inert gas in the high-temperature section is recovered by a waste heat boiler, and the inert gas in the medium-temperature section is used in a coal dryer to meet the required gas temperature conditions. An inert gas system that divides the waste heat boiler and coal dryer into two systems by directly introducing inert gas at the appropriate temperature from a dry fire extinguisher to different waste heat boilers and coal dryers without pretreatment. A heat recovery method in a coke dry extinguishing method, which is characterized in that it is used in parallel in a coke system. 3 In the grate dry extinguishing method for coke using inert gas, the inert gas passing through the inert gas passage in the dry extinguisher, which is divided into multiple sections in the direction of movement of the grate by a sealing partition plate, is divided into a high-temperature section and a medium-temperature section. The inert gas in the high-temperature section is recycled and supplied to the dry fire extinguisher after heat recovery in the waste heat boiler, and the inert gas taken out from the medium-temperature section is directly used to dry the coal. After drying the raw material coal sent to the machine, dust is removed and dehumidified, and the inert gas is circulated and supplied to the dry fire extinguisher.
A heat recovery method in coke dry extinguishing method, which is characterized by cyclic use in the system.