CN-122007122-A - Gradient dehydration and recycling pretreatment system and method for zero-emission waste salt of high-salt wastewater

CN122007122ACN 122007122 ACN122007122 ACN 122007122ACN-122007122-A

Abstract

The application discloses a gradient dewatering and recycling pretreatment system and method for high-salt wastewater zero-emission waste salt, wherein the system comprises at least two parallel draining units, each draining unit comprises a combined tank body, the tank body is divided into an upper independent cavity and a lower independent cavity by a middle partition plate, the upper cavity is a waste salt storage draining cavity, the lower cavity is a leachate collecting cavity, a plurality of round draining holes are uniformly distributed on the middle partition plate, draining caps are arranged on the draining holes, the leachate collecting and treating units are used for collecting leachate in each leachate collecting cavity, the multifunctional grab bucket is used for turning and pressurizing the waste salt, and the material transferring device is arranged above the draining units and used for controlling the multifunctional grab bucket to move in an XYZ space. The application skillfully solves the industrial problem of the dehydration bottleneck of the lower layer material in static draining, and stably reduces the water content of the waste salt by adopting a circulating refining concept in a mode of taking physical draining as a main part and flexible mechanical extrusion as an auxiliary part.

Inventors

ZHAO GUOPING
REN WEIHUI
ZHANG YILI
HE YANGYANG
ZHAO SHUQIN
WU HONGBING

Assignees

浙江浙能科技环保集团股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (9)

1. A gradient dehydration and recycling pretreatment system for zero-emission waste salt of high-salt wastewater is characterized by comprising: At least two parallel draining units, each draining unit comprises a combined tank body, the tank body is divided into an upper independent cavity and a lower independent cavity by a middle partition plate, the upper cavity is a waste salt storage draining cavity, the lower cavity is a leachate collecting cavity, a plurality of circular draining holes are uniformly distributed on the middle partition plate, and draining caps are arranged on the draining holes; the leachate collecting and treating unit is used for collecting leachate in each leachate collecting cavity; the multifunctional grab bucket is used for turning and pressurizing the waste salt; The material transfer device is arranged above the draining unit and used for controlling the multifunctional grab bucket to move in the XYZ space.
2. The system of claim 1, wherein the drain cap has a filtering accuracy of 50-200 microns and is made of ABS, PVDF or ceramic.
3. The system of claim 1, wherein the inner wall of the combined tank body and the surface of the middle partition plate are provided with anti-corrosion layers, and the anti-corrosion layers are made of glass fiber reinforced plastic or polyethylene.
4. The system of claim 1, wherein the leachate collection and treatment unit comprises a brine reflux pump and a slurry pump, the brine reflux pump is disposed outside an upper portion of the leachate collection chamber for returning saturated brine of an upper inner layer of the leachate collection chamber to the evaporative crystallization system, and the slurry pump is disposed at a bottom portion of the leachate collection chamber for returning fine salt-containing slurry of an inner bottom layer of the leachate collection chamber to the corresponding waste salt storage chamber.
5. The system of claim 4, wherein the bottom inner wall of the leachate collection chamber is provided with an inclined slope and a sump is provided below the lowest side of the slope, and wherein the slurry pump is provided in the sump.
6. The system of claim 1, wherein an elastic pad is laid on the inner side of the bucket flap of the multifunctional grab bucket, so that after the bucket flap of the multifunctional grab bucket is opened to grab the waste salt, the bucket flap of the multifunctional grab bucket can apply flexible static pressure uniformly distributed to the waste salt in the bucket flap of the multifunctional grab bucket in a closed state.
7. The system of claim 1, wherein the material handling device comprises a rail-mounted motorized cart and a lift mechanism disposed on the rail-mounted motorized cart, the rail-mounted motorized cart capable of controlling the lift mechanism to move in an XY plane, the multi-functional grab disposed at a lower end of the lift mechanism, the lift mechanism capable of controlling the multi-functional grab to move up and down in a Z-axis direction.
8. The system of claim 1, wherein the sidewall of the spent salt storage chamber is provided with a high pressure flushing device.
9. The method for pretreatment of salt waste water draining by the system of claim 1, wherein the salt waste is treated in the following gradient order: s1, conveying wet waste salt produced by an evaporation crystallization system to an upper waste salt storage and leaching cavity of one leaching unit; S2, standing wet waste salt in a waste salt storage and leaching cavity, performing gravity free leaching, removing most of free water, and enabling leachate to flow into a lower leachate collection cavity through a leaching cap on an intermediate partition plate; S3, a second gradient, namely during or after infiltration, operating the multifunctional grab bucket to carry out at least one grabbing, lifting and throwing turning operation on the waste salt in the waste salt storage and infiltration cavity, reconstructing a salt layer through mechanical turning, destroying a capillary structure, and promoting deep water to be converted into free water and infiltration again; S4, third gradient, namely after turning over in the step S3, operating the multifunctional grab bucket to grab the waste salt, then closing the multifunctional grab bucket to apply flexible static pressure to the waste salt in the multifunctional grab bucket, and extruding residual capillary water and weak bound water by applying uniform flexible static pressure; s5, alternately performing the steps S3 and S4 one or more times until the water content of the waste salt reaches a preset target; s6, controlling the movement of the multifunctional grab bucket through the material transferring device, transferring the drained waste salt out and sending the drained waste salt into a hopper of a subsequent drying treatment unit, and simultaneously recycling supernatant in the leachate collecting cavity to the evaporation crystallization system, and returning fine salt-containing slurry at the bottom of the leachate collecting cavity to a corresponding waste salt storage cavity for treatment.

Description

Gradient dehydration and recycling pretreatment system and method for zero-emission waste salt of high-salt wastewater Technical Field The invention relates to the technical field of industrial wastewater treatment and solid waste recycling, in particular to a gradient dehydration and recycling pretreatment system and method for zero-emission waste salt of high-salt wastewater. Background "Zero emission" has become a necessary requirement for wastewater treatment in high water consumption industries (such as coal chemical industry, electric power, pharmacy, printing and dyeing, etc.). At the end of the zero emission process, the soluble total solid is finally converted into solid waste salt by multiple effect evaporation, MVR and other evaporation crystallization technologies. However, such waste salt components are complex (often containing NaCl, na 2SO4 and a small amount of impurities such as heavy metals and organic matters), and are mostly identified as dangerous wastes, and the conventional disposal mode is landfill, so that not only land resources are occupied, but also environmental risks exist, and the policy guidance of 'no waste city' and circular economy is violated. Promotes the harmlessness and the recycling of waste salt to become industry consensus and development trend. The existing high-salt wastewater is continuously concentrated and reduced in the treatment process, so that a great amount of organic matters are enriched in the tail end wastewater before the tail end wastewater enters an evaporation and crystallization system, waste salt produced by the evaporation and crystallization system is usually discharged in the form of salt slurry or wet salt cake, the water content is high and is generally between 10 and 30 percent, and the waste salt becomes a key technical bottleneck existing before the waste salt is sent to a recycling process (such as high-temperature melting, high-temperature oxidation, industrial product preparation and the like). The direct drying of the waste salt with high water content has huge energy consumption, and the evaporation of water consumes a great amount of heat energy, thus greatly increasing the equipment investment and the operation burden. The large amount of moisture also increases the ineffective transport and disposal volume of hazardous waste, causing unnecessary expense. When the traditional mechanical draining equipment (such as plate and frame filter pressing) is used for such waste salt with high COD, high corrosiveness and uneven crystals, the problems of high investment, easy blockage, difficult maintenance, poor adaptability and the like exist. Therefore, development of a special dewatering pretreatment technology and device aiming at the characteristics of waste salt, low cost, high efficiency, stable operation and easy maintenance is needed, and aims to stably reduce the water content of the waste salt to below 10% by using a physical draining method as a main and flexible mechanical extrusion method as an auxiliary way through a cyclic refining concept, thereby creating favorable conditions for the subsequent deep drying and recycling process and further opening the economic and technical bottleneck of a full chain for recycling the waste salt. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a waste salt dehydration pretreatment system and a waste salt dehydration pretreatment method which have the advantages of simple system structure, low investment and operation cost, stable dehydration effect, adaptation to waste salt with complex physical properties and realization of internal circulation of leachate, so that the water content of the waste salt is effectively reduced to below 10%, and a large amount of energy consumption and cost are saved for subsequent treatment. The technical scheme adopted by the application is as follows: a gradient dehydration and recycling pretreatment system for zero-emission waste salt of high-salt wastewater comprises: At least two parallel draining units, each draining unit comprises a combined tank body, the tank body is divided into an upper independent cavity and a lower independent cavity by a middle partition plate, the upper cavity is a waste salt storage draining cavity, the lower cavity is a leachate collecting cavity, a plurality of circular draining holes are uniformly distributed on the middle partition plate, and draining caps are arranged on the draining holes; the leachate collecting and treating unit is used for collecting leachate in each leachate collecting cavity; the multifunctional grab bucket is used for turning and pressurizing the waste salt; The material transfer device is arranged above the draining unit and used for controlling the multifunctional grab bucket to move in the XYZ space. Further, the waste salt storage and leaching cavity is an open-top tank body and is used for receiving and storing wet waste salt, and waste salt from