JPS6316032B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a louver that feeds hot gas from below into a cylindrical rotating body, and allows the hot gas to pass through a wet material, such as coal, that is supplied into the rotating body. The present invention relates to a rotary flow type drying/heating machine having a built-in heat exchanger tube that dries and heats the wet material while fluidizing it.

Conventionally, there have been the following types of cylindrical rotary fluid dryers for drying wet materials.

(1) A single-barrel rotary dryer that scrapes the material using scraping plates or partition plates installed on the inner surface of the cylinder and brings it into direct contact with hot air for drying.

(2) As shown in FIG. 1, a heat medium heat transfer tube 2 such as steam is laid on the inner surface of the rotating body 1, and the wet material supplied from the raw material inlet 3 provided at one end is transferred to the heat medium heat transfer tube 2. A rotary dryer with a heat transfer tube that guides the heat medium to the other end while heating it with a heat exchanger tube 2, and discharges it as a dry material from a product outlet 4 provided at the other end. In the figure, 5 is an inlet for steam etc. introduced into the heat transfer tube 2, 6 is an air inlet, and 7 is an air outlet. They are provided at both ends of the rotary body 1 to allow the wet material to flow and dry efficiently.

(3) As shown in FIGS. 2a and 2b, a louver 9 is provided inside the rotating body 8, and the inner surface of the rotating body 8 and the louver 9
A hot air inlet 10 at one end in a space consisting of
A ventilation rotary dryer that introduces hot gas 11 from a raw material inlet 12 and causes the hot gas 11 to pass through a wet material 13 supplied from a raw material inlet 12 for drying. In the figure, reference numeral 14 denotes an outlet hood, which discharges the dry material 15 from its lower end and exhausts the waste gas 11 inside the rotating body 8 from its upper end.

However, these rotary dryers simply dry wet materials, so when fine-grained wet materials are dried, the fine particles contained therein become particulate dust, and the dry material and this generated dust are mixed. Dust was often introduced into subsequent equipment, causing handling problems. Incidentally, in recent years there have been calls for the use of coal as a substitute for petroleum, and coking coal, which is consumed in large quantities especially for steelmaking, is also part of advanced utilization methods in the steelmaking process. In such a case, the coking coal, ie, the wet material, is made into a dry material using a rotary dryer as described above, and this dry material is fed to a coke oven. It has also been considered to introduce combustion exhaust gas from a coke oven into the rotary dryer and utilize it effectively to save energy. However, as mentioned above, conventional rotary dryers simply dry, so as the coking coal for coking in the rotary dryer becomes dryer, the amount of particulate dust rapidly increases, causing the production of coke ovens to increase. This has caused problems such as making it difficult to collect dust, increasing the load on dust collection, and increasing the load on the tar treatment process. Therefore, it is not possible to dry coking coal to a constant moisture content (1 to 2%) in a rotary dryer while suppressing the generation of particulate dust, much less to completely dry and heat the coking raw material. Nakatsuta.

Therefore, the present invention provides a rotary flow type drying/heating machine with a built-in heat transfer tube that solves such problems.The feature of the present invention is that a heat transfer tube for a heat medium such as steam is disposed inside the rotating body. The inside of the rotating body is partitioned from the upstream side to the downstream side into a drying zone, a classification zone, and a heating zone, and a supply pipe is provided to supply hot gas to the heating zone, and the exhaust gas in the heating zone is divided into a drying zone and a heating zone. A supply pipe is provided to supply the exhaust gas in the drying zone and the classification zone to the outside of the system, and an exhaust pipe is provided to discharge the exhaust gas in the drying zone and the classification zone to the outside of the system. Gas is supplied, and the hot gas supply flow rate in the heating zone is limited to the same or lower than that in the classification zone. According to this configuration, wet materials such as coal are almost dried, dust is removed, Furthermore, completely dry and heated, large,
It is possible to achieve an energy saving effect.

Hereinafter, one embodiment of the present invention will be described based on FIGS. 3 and 4. This embodiment relates to a coal drying/heating machine. Reference numeral 20 denotes a rotary body rotatable in the direction of arrow A; 21 denotes a large number of louvers disposed on the inner circumferential surface of the rotary body 20; 22 and 23 denote louvers arranged on the inner circumferential surface of the rotary body 20 in the longitudinal direction of the rotary body 20; These are ring-shaped and cylindrical partition plates arranged at appropriate intervals along the rotary body 20, so that the inside of the rotating body 20 is divided from the upstream side to the downstream side into a drying zone 24, a classification zone 25, and a heating zone 26. It is divided. Reference numeral 27 denotes a heat transfer tube disposed inside the rotating body 20 along the louver 21, and is connected to a supply tube for a heat medium such as steam. 43 is a drain. 28 is the rotating body 20
29 is a coal charging tube that penetrates the sealing lid 28 and fits into the rotary body 20; 30 is an outlet hood that covers the downstream end of the rotary body 20; dry coal outlet 31,
It has an exhaust port 32 at the top. 35 is a third supply pipe 33 for supplying inert or low oxygen concentration hot gas discharged from a coke oven or the like into the heating zone 26;
34 is a first supply pipe for supplying exhaust gas from the heating zone 26 into the drying zone 24, and 34 is the first supply pipe 3.
A second supply pipe branched from 3 to supply exhaust gas from the heating zone 26 into the classification zone 25, 36 a discharge pipe for discharging gas from the drying zone 24 and the classification zone 25, and 38 a first supply pipe. A fan 39 interposed in the pipe 33 is an air heater interposed in the first and third supply pipes 33 and 35. Note that the air heater 39 may be omitted when the gas temperature is sufficiently high. 40 and 41 are dust collectors and fans interposed in the discharge pipe 36, and 44 is a fan interposed in the third supply pipe 35. In addition, the flow rate through the coal seam of the hot gas supplied from the third supply pipe 35 into the heating zone 26 is set to be equal to or lower than the flow rate through the coal seam of the exhaust gas supplied into the classification zone 25 from the second supply pipe 34. This is to prevent unnecessary scattering of coal particles. Further, from the third supply pipe 35 to the heating zone 2
It is important that the hot gas supplied into the chamber 6 be a combustion exhaust gas or the like with a low oxygen concentration, preferably an inert gas, and be a hot gas that prevents combustion of flammable materials such as coal and deterioration such as oxidation. 37 is a bleed-off for releasing excess exhaust gas from the heating zone 26 to the outside of the system due to gas balance, and 42 is a bleed-off to discharge excess gas from the heating zone 26 to the outside of the system due to gas balance.
This hot gas pipe is used to supply hot gas to the drying zone 24 and classification zone 25 in case of shortage.

In the above configuration, when coal is thrown into the coal charging cylinder 29, the coal is thrown onto the louver 21 of the rotary body 20, which slowly rotates in the direction of arrow A. Then, the exhaust gas sucked by the fan 28 from the heating zone 26 through the first supply pipe 33 is supplied into the drying zone 24, and is blown up from the louver 21 toward the coal supplied as described above. Dry the coal. The coal dried in the drying zone 24 enters the classification zone 25 and is supplied from the second supply pipe 34, and the dust that is present in the dried coal is blown up by the exhaust gas that is strongly blown up from the louver 21 and removed from the coal. be done. This blown up particulate-generating dust enters the dust collector 40 through the discharge pipe 36, is removed, and is discharged out of the system by the fan 41. The completely dried coal from which dust has been removed in the classification zone 25 enters the heating zone 26, where it is heated to 100 to 200°C and supplied to the coke oven. For example, heating coking coal to 200℃ can shorten the carbonization time in a coke oven by more than 50% compared to the case without conventional drying, and also by 10% compared to the case of drying only. %
The above productivity will be improved. The coal heated in the heating zone 26 is discharged from the outlet 31 of the outlet hood 30 and is conveyed to the coke oven by a conveyor (not shown).

As described above, according to the rotary flow type drying/heating machine incorporating the heat transfer tube of the present invention, it is possible to dry a wet material, remove dust attached to the material, and completely dry the material. It is ideal for drying and preheating coking coal, and can significantly reduce the carbonization time in a coke oven compared to conventional methods. In addition, since the exhaust gas from the heating zone is supplied to the drying zone and the classification zone for reuse, thermal efficiency is good, and if combustion waste gas from a coke oven is used as a heat source, even more energy can be saved. It is something that can enhance the effect.

[Brief explanation of the drawing]

Fig. 1 and Fig. 2 show conventional examples, Fig. 1 is a perspective view of a rotary dryer with heat exchanger tubes, Fig. 2 a is a vertical sectional view of the ventilation rotary dryer, and Fig. 2 b is Fig. 2 a. A-
A sectional view, FIGS. 3 and 4 show one embodiment of the present invention, FIG. 3 is a longitudinal sectional view of a rotary fluid dryer with a built-in heat transfer tube, and FIG. This is a perspective view. 20... Rotating body, 21... Louver, 22,2
3... Partition plate, 24... Drying zone, 25... Classifying zone, 26... Heating zone, 27... Heat exchanger tube, 33...
1st supply pipe, 34...2nd supply pipe, 35...3rd supply pipe
Supply pipe, 36...discharge pipe, 40...dust collector.

Claims (1)

[Claims] 1. A rotary fluid dryer in which a louver is provided in a cylindrical rotating body to feed hot gas from below, and the hot gas is passed through the wet material supplied into the rotating body to fluidize and dry the wet material. , disposing a heat transfer tube for a heat medium such as steam in the rotating body, partitioning the rotating body from the upstream side to the downstream side into a drying zone, a classification zone, and a heating zone, and supplying hot gas to the heating zone. A supply pipe is provided to supply the exhaust gas in the heating zone to the drying zone and the classification zone, and a discharge pipe is installed to discharge the exhaust gas in the drying zone and classification zone to the outside of the system, and the exhaust gas is supplied to the heating zone. It has a built-in heat exchanger tube that supplies inert or low oxygen concentration hot gas, such as combustion gas, and limits the hot gas supply flow rate in the heating zone to the same or lower than that in the classification zone. A rotary flow type drying and heating machine.