JPS6060185A - Method for pretreating coal in dry distillation stage - Google Patents

Abstract

PURPOSE:To obtain safely and inexpensively coke of good quality by efficiently reducing the water content of coal at a relatively low temp., by heating coal by feeding superheated steam while stirring coal as a pretreatment in the dry distillation of coal. CONSTITUTION:Coal C is fed to a screw feeder 21 and moved toward the left end within a preheater 10 for coal while stirring it at a low speed with an agitating rake. At the same time, superheated steam S is fed through a superheated steam supply port and countercurrently contacted with coal C to vaporize water contained in coal C. Then coal C is continuously discharged through a coal discharge device 4 and fed to a coke oven where coal is subjected to dry distillation to produce coke. Steam contg. water vapor evaporated from coal C is discharged through a steam discharge port 13, dust is removed in a dust removing device, and the resulting steam is heated in a heater and recycled as superheated steam S to the preheater 10 for coal for reuse.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preheating coal. More specifically, like in the coke manufacturing process, coal is preheated to a predetermined temperature,
The present invention provides an optimal preheating method for the process of further carbonizing this to produce ':1-cus.

In conventional coke ovens, coal is charged into a chamber-shaped coke oven, which is preheated to reduce the moisture contained in the coal, and then carbonized to produce coke. A method to do so has been implemented.

In the coke manufacturing process, coal is continuously preheated and carbonized in a chamber-like coke oven.
) is configured. The preheating process and the carbonization process have very different functions, and since coke is essentially a carbonization process, separating the preheating process is considered to be advantageous in terms of thermal economy, etc. .

In addition, the preheating stage and the second stage (carbonization) are not separated, but the coal is charged into a chamber-like coke oven and the preheating stage is not stirred.・Since the water evaporation rate is low, a lot of 11S is required for preheating.
This has the disadvantage that it requires time and cannot be uniformly preheated in a short period of time.

When considering the separation of the preheating process, a method of heating by supplying an inert gas such as nitrogen gas has conventionally been applied in research, etc., but in this method, the state of the atmospheric gas is similar to that of coal. It is extremely difficult to maintain the inert gas in a constant state because it changes moment by moment depending on the state of heating. The concentration of nitrogen gas decreases when nitrogen gas is mixed with carbon dioxide that has evaporated from coal, etc., so to prevent this, it is necessary to adjust the nitrogen gas concentration. It costs a lot of money to adjust the gas.

The purpose of the present invention is to solve the problems in the preheating process as a pretreatment process for coal in the conventional coke oven. This is a pretreatment method for carbonizing coal into two culms, which is characterized by contacting the coal with superheated steam while stirring.

Embodiments of the present invention will be explained below with reference to the drawings.

FIG. 1 is a cross-sectional view showing an outline of a coal preheating device for carrying out an embodiment of the present invention, and FIG. 2 is a cross-sectional plan view of the same.

1 is the main body of the preheating device, and there is a charcoal 41 supply part 2 at the end.
A stirring transfer rake 3 is provided at the bottom, and a pre-charcoal extraction device 4 is provided at the transfer end. A supply port 5 for superheated steam is provided at a position far from the supply section 2 in the main body RB.

In the present invention, superheating is used as a heat transfer medium when preheating coal! The feature is that water is used, and this superheated steam has a high interfacial heat transfer rate, can superheat coal at a low temperature, and can prevent local deterioration of coal due to local heating. It is also excellent in that it has properties as an inert gas.

Specifically, the characteristics of the heated steam are such that the interfacial conductivity during forced convection is 5 to 20 XlO (Kcal/mh"C).
, which is much larger than the 2 to 8 x 10 for air and gases during forced convection.

Of coke! ! (The preheating temperature of coal that goes down to about 1↓-L is about 320°C at most, and the temperature of the medium used for it is about 400°C at most.

Therefore, in carrying out the present invention 1;) the heat supply to the coal preheating device! %A*'The maximum temperature of air is 400'C or a value close to this. In that case, the temperature of the superheated steam is 300 degrees, and the steam flow rate is 1.2 to 3 tons, preferably 1.5 to 1.5 tons, per ton of coal.
6 too.

FIG. 3 is a schematic diagram showing a flowchart of the coal preheating device according to the present invention. The steam supply port 5 of the coal preheating device 10 and the steam heater 11 are connected by a pipe 12, and the steam exhaust A dust removal wedge device 15 is connected to the outlet 13 via a pipe t114, and this removal 11μ device 15 is connected to a pipe 16. Blower 17.
It is connected to the steam heater 11 via piping 18,
As a whole, it constitutes a steam circulation flow path.

The coal supply section 2 is provided with a screw feeder 21 driven by a morph 20, for example, as shown in FIGS. 1 and 2.
In the figure, coal (', 4.1 is supplied from the right end, and stirred by stirring rake 3.
While being stirred! However, the superheated steam S supplied from the superheated steam supply port 5 flows from the left end to the right end, and during that time, the coal C and the steam S exchange heat in a countercurrent manner.

The coal C supplied from the supply section 2 of the coal preheating device 10 is stirred at a slow speed by a stirring rake while being agitated by the steam S supplied from the superheated steam supply port 5. Once heated to a predetermined temperature, the coal is continuously discharged by a single IJI outlet device, and then supplied to a coke oven (not shown), where it undergoes carbonization and becomes coke.

On the other hand, the superheated steam S contains moisture generated from the coal while passing through the coal preheating device 10, and is also discharged from the steam outlet 13, including dust generated from the coal, or is removed from the dust by the abatement device 615. Excess water is removed.

The steam supplied to the blower 17 is saturated steam or almost saturated steam, but it is added by the steam heater 11 and becomes superheated steam S with a predetermined degree of superheating. and is supplied into the coal preheating device 10.

Note that 22 is a water discharge valve, 23 is a valve for opening and closing piping 24, and piping 25 is a piping for supplying superheated steam from the boiler.

Since the present invention is configured as described in 1-1 below, it can exhibit the following effects.

(B) The interfacial conductivity of excess steam in the forced flow is significantly higher than that of nitrogen scum or air, so coal can be heated at a low temperature of 2+'li1 degrees, and ,
Local alteration of coal due to local heating can be prevented,
After all, it is possible to produce coke of intermediate quality.

(IJ) Coal forecast in the second stage of "Normal coke production"! °The maximum streak temperature is about 320℃, is the medium used? l
'l! The maximum L degree is about 400℃, but the
．． There is almost no danger of igniting the coal in a forced convection atmosphere of 3:4% F and 76 atmospheres at 114 degrees Celsius.

(c) The moisture in the coal itself evaporates during coal heating, but
In the present invention, since superheated air is used as the heating medium, the composition of the medium itself does not change.

For example, when nitrogen gas is used as the inert gas, it is always necessary to adjust the 110 nitrogen gas, but this is not necessary in the present invention. 'J coke manufacturing cost is low].

(-1-) Coal no. rj', jL temperature 320-35 (
1'c is the quasi (1ii
Although it is considered to be stage i, the atmosphere of superheated steam at this stage is better for carbonization characteristics. For example, even with relatively poor quality coal for carbonization due to its degree of coalification, the results are good. can do.

In addition, as a pretreatment for the carbonization process of coal (during the dry distillation process, it is usually not pressurized, or it is possible to achieve better results than C11 by applying a pressure of several kg/cnl). be.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view schematically showing a coal preheating device, FIG. 2 is a plan view thereof, and FIG. 3 is a diagram showing a flow of a coal superheating process. l... Preheating device: iq main body, 2... supply section, 3...
Stirring rake, 4... Coal discharge port, 5... Superheated steam supply [-1, 10... Coal preheating device, 11... Air adding device, 15... Dust removal device, 17. ...Blower, 21
...screw feeder.

Claims (1)

[Claims] While stirring the coal! ! ) A pretreatment method for a carbonization process of coal, characterized by supplying steam and heating it.