JPH0816010B2 - Dewatering method and equipment for zeolite slurries of coal ash - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to effective use of coal ash generated in a power plant or the like using coal as an energy source.

[0002]

2. Description of the Related Art In recent years, a large amount of coal ash generated in a power plant using coal as a heat source has been added as a material with added value due to its simple use such as landfill disposal, utilization as a cement raw material, and utilization as a roadbed material. The use has come to be oriented.

As one of them, there is a reuse method in which it is chemically treated to be an ion exchange agent, an adsorbent, and a zeolite for a reaction catalyst.

This processing method is, for example, as introduced in "Clean Japan" 83 [1990.7],
The coal ash stored in the fly ash hopper is boiled and stirred in a reaction tank with a concentration-adjusted and temperature-adjusted caustic soda solution to obtain a slurry zeolite, and the caustic soda solution is removed by a vacuum filter through a buffer tank. Liquid is separated, washed with water, and dried to obtain the product.

[0005]

In the deliquoring treatment of the slurry zeolite product in the zeolite zeolitic treatment of coal ash, the amount of coal ash and caustic soda solution charged in the reaction tank and the amount of the caustic soda liquid in the reaction tank If the slurry concentration varies depending on the reaction conditions, and if the slurry concentration is too high, the filter for deliquoring will be clogged and the deliquoring efficiency will be extremely reduced. I'm giving.

[0006] The problem to be solved in the present invention is to effectively eliminate the clogging of the filter in the deliquoring process of the zeolite-forming reaction product formed in the form of slurry, and to stabilize the whole process of zeolite-forming coal ash. Is to find a way to do it.

[0007]

The present invention is characterized in that the slurry to be dewatered is admixed with a caustic soda filtrate obtained by dewatering to obtain an optimum slurry concentration for dewatering. .

In order to carry out this, it is possible to use a device in which the filtrate discharge pipe from the dewatering device is provided with a branch pipe to a storage tank for zeolite slurry.

[0009]

[Operation] Confirm the optimum zeolite concentration in the slurry for the dewatering device in advance, and supply caustic soda solution in an amount that is the difference between the slurry concentration obtained by the zeolite conversion reaction tank and the optimum concentration. The concentration of the supplied slurry can be always kept constant.

[0010]

EXAMPLE FIG. 1 shows an outline of a liquid removing apparatus according to an example of the present invention.

In the figure, reference numeral 1 denotes a buffer tank in which the zeolitized slurry obtained in the previous step is temporarily stored and homogenized by a stirrer 2. Denoted at 3 is a vacuum type dewatering device, which is a filter bag 5 by a vacuum pump 4.
Is a method of sucking. 6 is a filter bag 5
The carrier which discharges the deliquored zeolite cake exfoliated from is shown. Reference numeral 7 denotes a slurry supply pipe for supplying the slurry to the liquid remover 3 from below the buffer tank 1 by the slurry pump 8. Reference numeral 9 denotes a filtrate return pipe for returning the filtrate of the liquid remover 3 to a reaction caustic soda solution storage tank (not shown) for reuse. 10 is a filtrate pump. A branch pipe 11 for supplying the filtrate to the position above the buffer tank 1 is provided on the downstream side of the filtrate pump 10 of the filtrate return pipe 9. 12 is a buffer tank 1 via a branch pipe 11.
Measure the amount of caustic soda filtrate added and supplied to the branch pipe 1
The integrated flowmeter for adjusting the opening degree of the shutoff valve 13 provided in FIG.

In such an apparatus, the integrated flow rate meter 12 determines the integrated flow rate in accordance with the required filtrate return amount determined in advance from the amounts of coal ash and caustic soda solution charged into the reaction tank, and the integrated flow rate flows to the branch pipe 11. When the accumulated amount of the filtrate is reached, a command is issued to operate the shutoff valve 13. Then, by repeating this operation for each processing batch of the supplied slurry, it is possible to always perform the deliquoring of the slurry having a constant concentration.

[0013]

According to the present invention, the following effects can be obtained.

(1) Since the slurry concentration can be constantly maintained at a constant level, the liquid removal process can be maintained in the optimum state.

(2) Since the clogging of the drainage filter bag can be eliminated, the life of the filter bag can be extended.

(3) Since the deliquored zeolite cake having a certain thickness can be obtained after a certain period of time, the whole process of zeolite formation can be stabilized.

[Brief description of drawings]

FIG. 1 shows an outline of a liquid removing apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 Buffer Tank 2 Stirrer 3 Drainer 4 Vacuum Pump 5 Filter Bag 6 Conveyor 7 Slurry Supply Pipe 8 Slurry Pump 9 Filtrate Return Pipe 10 Filtrate Pump 11 Branch Pipe 12 Integrating Flowmeter 13 Shutoff Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideo Kato 5-3 Tokai-cho, Tokai-shi, Aichi Pref. Nippon Steel Co., Ltd. Inside the Nagoya Works (72) Junsuke Haruna 5-3 Tokai-cho, Tokai-shi, Aichi Nippon Steel Co., Ltd. Nagoya Steel Works (72) Inventor Shuichi Kobayashi 5-3 Tokai-cho, Tokai-shi, Aichi Industrial Promotion Co., Ltd. Nagoya Works (56) Reference JP-A-63-182214 (JP, A)

Claims (2)

[Claims] 1. In the step of deliquescing and separating the slurry-like zeolite after making coal ash into a slurry-like zeolite with a caustic soda solution, the caustic soda filtrate obtained by the de-liquoring treatment is added and blended. A method for deliquoring a zeolitized slurry of coal ash to obtain an optimum slurry concentration for deliquoring. 2. A slurry supply pipe extending from a slurry zeolite storage tank to a dewatering device and a filtrate return pipe from the dewatering device, and a branch pipe leading to the storage tank is provided in the filtrate returning pipe. A liquid removal device for the zeolite slurries of coal ash provided.