Method and apparatus for direct drying of inorganic sludge with drum drawing process

Patent metadata

Field	Value
Publication number	US-2021347665-A1
Application number	US-201917278435-A
Country	US
Kind code	A1
Filing date	Sep 26, 2019
Priority date	Sep 29, 2018
Publication date	Nov 11, 2021
Grant date	—

Abstract

A method and apparatus for direct drying of inorganic sludge with a drum drawing process, comprising the following steps: 1) drum mixed drying of slag and sludge: respectively conveying the slag and sludge into a drum (1) in proportion, completing mixing, heat exchange, dehydration, cooling and crushing of the slag and sludge under the rolling action of the drum (1) and a steel ball to achieve cooling, crushing and drying of the slag and sludge, and directly discharging the obtained mixture; 2) slag and sludge separation: separating the steel slag and dry sludge in a manner of combining screening and rotary separation; 3) tail gas treatment: treating dusts, sulfides and organic compounds in tail gas generated by the dry sludge by using wet alkali washing and activated carbon adsorption, and discharging the treated tail gas; and 4) tailing sludge treatment: generating steam and dusts in the drum treatment of the slag and sludge, allowing dusts to enter a tail gas treatment device (4) with steam, aggregating the dusts after wet washing or spraying, and then conveying into a tailing sludge blending device (5) by means of a conveying device, mixing and stirring the tailing sludge and original sludge, conveying the obtained mixture into the drum (1), and drying the mixture to realize zero discharge of undried sludge.

First claim

1 . A method of drying inorganic sludge with molten slag, comprising the following steps: mixing slag and sludge; and separating steel slag and dry sludge after a water content of the sludge is reduced to 3%-15%.

2 . The method of drying inorganic sludge with molten slag according to claim 1 , wherein a mixing mass ratio of the slag to the sludge is 1.5-3.

3 . The method of drying inorganic sludge with molten slag according to claim 1 , wherein the steel slag and the dry sludge are separated by a combination of screening and spinning.

4 . The method of drying inorganic sludge with molten slag according to claim 1 , wherein the method further comprises a tail gas treatment step and a tail sludge treatment step.

5 . The method of drying inorganic sludge with molten slag according to claim 4 , wherein
the tail gas treatment comprises: treating dust, sulfides and organic compounds existing in a tail gas generated during the drying of the sludge by means of wet alkaline washing and/or activated carbon adsorption, and then discharging the tail gas; the tail sludge treatment comprises wet washing or sprinkling the resulting dust, collecting the dust, mixing the dust with sludge to be dried, agitating, and mixing with slag for drying treatment.

6 . The method of drying inorganic sludge with molten slag according to claim 1 , wherein the slag and the sludge are mixed in a drum containing steel balls.

7 . The method of drying inorganic sludge with molten slag according to claim 6 , wherein the method comprises: conveying the slag and the sludge to the drum containing the steel balls with respective conveying devices; and after the water content of the sludge is reduced to 3%-15%, conveying a mixture of the steel slag and the dry sludge to a slag-sludge separation device with a slag-sludge conveying device positioned at an outlet end of the drum to separate the steel slag from the dry sludge, wherein dust, sulfides and organic compounds existing in a tail gas generated during the drying of the sludge enter a tail gas treatment device from a drum outlet, and the gas is discharged when it satisfies the discharge standard after the treatment; wherein the dust separated in the tail gas treatment enters a tail sludge mixing device from a dust mud outlet of the tail gas treatment device, mixes with sludge to be dried, and is then conveyed to the drum through a mud conveying pipeline.

8 . The method of drying inorganic sludge with molten slag according to claim 3 , wherein the slag-sludge separation device utilizes a screening process, wherein a screen mesh number is not less than 60 meshes.

9 . The method of drying inorganic sludge with molten slag according to claim 1 , wherein mixing and drying are carried out in batches, by flow addition or by semi-flow addition.

10 . A method of directly drying inorganic sludge by a drum process, wherein the method comprises the following steps:
1) Mixing sludge with slag in a drum for drying wherein the slag and the sludge are conveyed to the drum with their respective conveying devices at a specific flow ratio; wherein the slag and the sludge are mixed, heat exchanged, dehydrated, cooled and broken under the action of rotation of the drum and rolling of steel balls, whereby the slag and the sludge are cooled and dried, followed by direct discharge; wherein the inorganic sludge has an initial water content of 70%-99%, and a target water content of 3%-15% after drying; wherein a slag/sludge flow ratio of the slag to the inorganic sludge is 1.5-3.0; wherein the inorganic sludge has a flow rate of 10 t/h-80 t/h; 2) Separating the slag from the sludge wherein the steel slag and the dry sludge are separated by a combination of screening and spinning; 3) Treating tail gas wherein wet alkaline washing and activated carbon adsorption are utilized to treat dust, sulfides and organic compounds existing in the tail gas generated during the drying of the sludge by the drum process, and then the gas is discharged; 4) Treating tail sludge wherein the dust generated in the tail gas treatment is wet washed or sprinkled, collected, and then conveyed to a tail sludge mixing device with a conveying device, wherein the dust is mixed with primary sludge, agitated, and then regularly conveyed to the drum with a sludge pump for drying treatment, wherein a difference between a water content of the tail sludge after mixing and agitation and the initial water content of the inorganic sludge does not exceed ±5%.

11 . The method of directly drying inorganic sludge by a drum process according to claim 10 , wherein in step 2), a screening process is used for separating the slag from the sludge, wherein a screen mesh number is not less than 60 meshes.

12 . An apparatus for directly drying inorganic sludge by a drum process, comprising:
a drum containing a number of steel balls; a slag-sludge conveying device having an inlet end corresponding to an outlet of the drum; a slag-sludge separation device having an inlet end corresponding to an outlet of the slag-sludge conveying device and outlets corresponding to different stock bins; a tail gas treatment device having a gas inlet connected to the outlet of the drum through a conveying pipeline; a tail sludge mixing device having an inlet connected to a dust mud outlet of the tail gas treatment device through a conveying pipeline; a mud conveying pipeline configured to connect an outlet of the tail sludge mixing device to an inlet of the drum; and a sludge pump arranged on the mud conveying pipeline for pumping the sludge to the drum.

13 . The apparatus for directly drying inorganic sludge by a drum process according to claim 12 , wherein the slag-sludge separation device utilizes a screening process, wherein a screen mesh number is not less than 60 meshes.

Assignees

• Baoshan Iron & Steel

Inventors

• Wang Yingjie
• Xiao Yongli
• Li Yongqian

Classifications

• B01D47/06

  Spray cleaning · CPC title

• B01D53/48

  Sulfur compounds · CPC title

• B01D2251/30

  Alkali metal compounds · CPC title

• B01D2253/102

  Carbon · CPC title

• B01D2258/02

  Other waste gases · CPC title