JPS60130675A - Method for drying coal to be fed in coke oven - Google Patents

Abstract

PURPOSE:To shorten coking time by effectively utilizing heat energy, by recovering steam from hot waste water discharged from a primary cooler under reduced pressure and drying coal to be fed in a coke oven by indirectly heating it wth said steam. CONSTITUTION:Coke oven gas from a coke oven 1 is cooled in a primary cooler 2 and fed to an ammonia recovery means 3. Hot waste water discharged from the cooler 2 is introduced through a pit 4 and a pump 5 into a flash tank 6 where steam is generated under reduced pressure. The generated steam is passed through a compressor 10 and fed to an indirect heating type dryer 7 (numeral 8 is a drain tank and 9 is a vacuum generating device). In a dryer 7, wet coal C to be charged in the coke oven is heated by using said steam as a heat source and the resulting dried coal d is charged in the coke oven 1. Liquids discharged from the flash tank 6 and the drain tank 8 are recycled to the primary cooler 2 by means of a pump 11 to use them.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a method for drying coal for coke oven charging, and more specifically, a method for recovering sensible heat from heated waste water used for cooling coke oven gas, The present invention relates to a method for drying charging coal that can achieve energy savings by effectively using it as a heat source for drying charging coal.

(Technical background of the invention and its problems) When producing coke by carbonizing coal, if the charged coal is warmed and dried to lower its moisture content, the coking time will be shortened and productivity will be increased. It is already known that it is effective in reducing the energy required for coking. However, since a large amount of energy is required to dry the charged coal, even if the charged coal is subjected to drying treatment in advance, the energy required for coal carbonization may not be saved much in the end. First of all, pre-drying of charged coal is almost never actually carried out because it is not possible to expect an energy-saving effect commensurate with capital investment. is cooled by a primary cooler or the like, but the heated waste water from the primary cooler used for this cooling has conventionally been discharged without being used. The inventors of the present invention paid attention to the sensible heat of the heated waste water of the primary cooler, and studied a method of effectively utilizing this as a heat source for drying charged coal. As a result, seawater is usually used to cool the (+) primary cooler;
If warm seawater is used as it is, scaling problems will occur, so the heat contained in the heated wastewater from the primary cooler is recovered in the form of paper under reduced pressure. (2) The recovered paper is compressed directly or with a compressor. It was discovered that the desired drying of the charged coal could be achieved while saving energy by leading the coal to an indirect heating type dryer after compression and using it as a heat source to dry the coal, leading to the present invention. .

(Object of the Invention) That is, an object of the present invention is to provide a coke that can dry coal for coke oven charging while saving energy, thereby reducing heat consumption during carbonization in a coke oven. An object of the present invention is to provide a method for drying coal for charging into a furnace.

(Structure of the Invention) In order to achieve this object, the present invention recovers the sensible heat of heated waste water of the primary cooler used for cooling coke oven gas as paper under reduced pressure, and recovers the sensible heat as paper at the same pressure or in the R It is characterized in that it is used as a heat source for an indirect heating type dryer for drying coal for charging into a coke oven.

(Specific Examples of the Invention) Next, the present invention will be explained in detail using specific examples shown in the drawings.

The drawing is a flow sheet of a system for drying coal for coke oven charging for carrying out the method of the present invention.

Coke oven gas generated from a coke oven 1 during carbonization of coal has a temperature of 600 to 800°C, and is sent to a primary cooler 2 and cooled by cooling seawater a, and then sent to an ammonia recovery facility 3.

70-75°C discharged from primary cooler 2
The warm seawater is sent to a flash tank 6 via a seawater pit 4 and a pump 5. The flash tank 6 is connected to a vacuum generator 9 via an indirect heating type dryer 7 and a drain tank 8 which communicates with the indirect heating type dryer 7 by piping. Therefore, the warm seawater fed to the flash tank 6 is operated under reduced pressure to form paper. This paper' can be directly or compressed into a compressor 10 to raise the temperature of the paper.
It is led to the dryer 7 via the dryer 7, and is consumed to heat and dry the wet coal C for coke oven charging supplied to the dryer. As the dryer 7, an indirect heating type dryer using paper as a heat source, such as a rotary dryer with a steam pipe, a fluidized bed dryer with a built-in heating tube, a jacket groove type dryer, etc. is suitable.

In addition, in the drawings, b indicates capacitor 1.
The water is recirculated to the primary cooler 2 by the pump 11 and is reused as part of the cooling water of the primary cooler 2. d indicates dry coal for coke oven charging that has been dried by the indirect heating dryer 7 and is supplied to the coke oven 1.

(Effects of the Invention) As described above, according to the present invention, the sensible heat of the heated waste water of the primary cooler used for cooling coke oven gas is
Since it is recovered as paper under reduced pressure and used as a heat source for drying the coal charged in the coke oven, the separate heat source that was previously required for drying is no longer required, and the entire coke manufacturing process is guaranteed to significantly save energy. In addition to achieving this, stable continuous operation is possible without reducing the overall heat transfer coefficient due to scale trouble on the heating side of the dryer.

(Example) Using the system shown in the drawings, wet coal for coke oven charging (average particle size 0.9 m+*) containing 10% moisture was mixed with
It was dried at 00 ton/hr until the moisture content reached 5z.

As the dryer, a rotary dryer with a steam pipe having a heat transfer area of 2000 rn' was used. The paper collected at 70°C in the flash tank was heated to 80°C by a compressor to improve the drying load and then sent to the dryer.

In the conventional method of drying (5% moisture) coal (1oz moisture) using steam as a heat source, the steam consumed acid is +
3 ton/hr, whereas in the present invention V, +
Only heated waste water from the primary cooler at 200 rn'/hr and 75° C. was used, and no steam was required.

[Brief explanation of the drawing]

The drawing is a flow sheet showing a system for drying coal for coke oven charging according to the present invention. 1. Coke oven 2. Primary cooler 6. Flush tank 7. Indirect heating dryer 8. Drain tank 9. Vacuum generator 10. Vacuum compressor a. Seawater bll-condensate C. Wet coal for coke oven charging d... Dry coal for coke oven charging Patent applicant Tsukishima Kikai Co., Ltd.

Claims (1)

[Claims] (1) Primary used for cooling coke oven gas
The sensible heat of hot wastewater from the cooler is recovered as paper under reduced pressure, and this paper is used as a heat source for an indirect heating dryer for drying coal for coke oven charging, either at the same pressure or at increased pressure. A method for drying coal for coke oven charging.