Online circulating washing method for household garbage incineration fly ash

Abstract

The invention provides an online circulating washing method for household garbage incineration fly ash, which comprises the following steps: mixing and stirring a first batch of fly ash and clear water to obtain a first batch of slurry; injecting the first batch of slurry into a plate-and-frame filter press by using a feeding pump, and collecting filtrate; respectively introducing one part of clear water into the plate-and-frame filter press for three times for washing, and collecting three washing solutions; after multiple times of washing, squeezing the plate-and-frame filter press, and collecting the press filtrate in the last washing solution to obtain a first batch of washing fly ash with the water content of 25%; weighing 1 part by mass of fly ash, 1 part by mass of the filtrate obtained in the previous step and 1 part by mass of the first washing solution obtained in the previous step, mixing and stirring to obtain a second batch of slurry; repeating the above steps, using the previous batch of primary and secondary washing liquid for the previous two times of washing, and supplementing clear water for the third time of washing to obtain the second batch of washing fly ash with the water content of 25%; and repeating the steps to obtain multiple batches of washing fly ash with the water content of 25%.

Description

Technical Field

[0001] This application relates to the field of municipal solid waste treatment technology, and in particular to an online circulating water washing method for municipal solid waste incineration fly ash. Background Technology

[0002] Municipal solid waste incineration fly ash is classified as hazardous waste due to its high toxicity from heavy metal leaching and dioxin toxicity. Furthermore, its high content of dioxins, chloride ions, and heavy metal ions severely restricts its resource utilization. During the resource recovery process of incineration fly ash, the high concentration of chloride ions can corrode equipment and affect the performance of the recovered products, thus limiting their utilization. Therefore, fly ash must undergo water washing to remove harmful components such as chloride ions during resource recovery.

[0003] Currently, the main fly ash washing process is a three-stage countercurrent washing process. This process involves mixing fly ash with a certain proportion of pulping water to form a pulp. After solid-liquid separation, a further proportion of pulping water is added to re-pulp the fly ash. This process is repeated three times, including pulping and filtration, to obtain washed fly ash with a chloride ion concentration that meets standards. However, this process is relatively complex, with multiple washing tanks and dewatering machines resulting in a long process flow and high energy consumption. Furthermore, the high water consumption leads to a large volume of subsequent washing liquid treatment, increasing costs.

[0004] Therefore, it is very important to provide an online circulating water washing method for municipal solid waste incineration fly ash that is simple in process and has a short process flow. Summary of the Invention

[0005] This application provides an online circulating water washing method for municipal solid waste incineration fly ash to solve the problems of cumbersome and energy-intensive existing fly ash washing processes in related technologies.

[0006] In one aspect, this application provides an online circulating water washing method for municipal solid waste incineration fly ash. This water washing method uses a plate and frame filter press to circulate and wash the slurry of fly ash and water to obtain water-washed fly ash with a moisture content of 25%.

[0007] In some embodiments, the online circulating water washing method specifically includes the following steps: S101, the first batch of fly ash is mixed with water to obtain the first batch of slurry; S102, the first batch of slurry is injected into the plate and frame filter press using a feed pump, and the filtrate is collected; S103, Pass clean water into the plate and frame filter press for the first washing, and collect the first washing liquid; S104, repeatedly pass clean water into the plate and frame filter press for two washings, and collect the second and third washing liquids; S105 After multiple washings, the plate and frame filter press is pressed to obtain the first batch of washed fly ash with a moisture content of 25%. S106, Weigh 1 part of fly ash, 1 part of filtrate from step S102, and 1 part of washing liquid from step S103 by mass, mix and stir to obtain the second batch of slurry; S107, repeat steps S102-S105. The first two washes use second and third washing liquid instead of clean water for the first and second washes. The third wash introduces clean water of the same mass as the fly ash, and the first, second and third washing liquids and the second batch of water-washed fly ash with a moisture content of 25% are obtained. S108, repeat steps S106-S107 to obtain multiple batches of water-washed fly ash with a moisture content of 25%, and the chloride ion content in the water-washed fly ash is less than 1%.

[0008] In some embodiments, the specific process of step S107 is as follows: Using 4kg / cm 2 The feed pump injects the second batch of slurry into the plate and frame filter press and collects the filtrate; The washing liquid collected in step S104 and clean water are introduced into the plate and frame filter press for three online circulating water washes, and the washing liquid is collected. Using 16kg / cm 2 The pressing pressure was applied to the plate and frame filter press, and after pressing for 10 minutes, a second batch of washed fly ash with a moisture content of 25% was obtained.

[0009] In some embodiments, in step S101, the mass ratio of fly ash to clean water is 1:2.

[0010] In some embodiments, in step S102, the flow rate of the feed pump is 4 kg / cm². 2 .

[0011] In some embodiments, in steps S103 and S104, the amount of clean water added each time is equal to the mass of fly ash.

[0012] In some embodiments, in step S105, the pressing pressure of the plate and frame filter press is 16 kg / cm². 2 The pressing time is 10 minutes.

[0013] In some embodiments, in step S107, when washing subsequent batches of fly ash online, the second and third washing solutions from the previous batch are used first, and finally a wash with clean water is used. The washing solutions from these three washes are collected for subsequent recycling.

[0014] The proposed solution involves washing multiple batches of fly ash with water. For the entire system, each batch of fly ash washed requires an additional batch of clean water, generating a batch of filtrate for water treatment and evaporation, which greatly reduces costs.

[0015] The beneficial effects of the technical solution provided in this application include: compared with the existing fly ash washing technology, the washing method of this application only uses a filter press for multiple circulating water washing, which requires less equipment. While ensuring that the chloride ion content of the washed fly ash meets the standard, the amount of clean water replenished for each batch of fly ash (ratio to fly ash mass) is 1:1 (the water replenishment amount of traditional washing methods is mostly 2-3 times the fly ash mass), which reduces the amount of water replenished and thus effectively reduces the production cost of fly ash washing. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the online circulating water washing method provided in Embodiment 1 of this application.

[0018] Figure 2 This is a schematic diagram of the online circulating water washing method provided in Embodiment 2 of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] This application provides an online circulating water washing method for fly ash from municipal solid waste incineration, which can solve the problems of cumbersome and high energy consumption in existing fly ash washing processes in related technologies.

[0021] Example 1: refer to Figure 1 The online circulating water washing method for municipal solid waste incineration fly ash provided in Example 1 includes the following steps: Step 1: Mix the first batch of fly ash with water at a ratio of 1:2 and stir for 40 minutes to obtain the first batch of slurry; Step 2: Use 4kg / cm 2 The feed pump injects the first batch of slurry into the plate and frame filter press and collects the filtrate in the filtrate tank for use in the next batch of fly ash pulping. Step 3: First, pass clean water of the same mass as the fly ash into the plate and frame filter press for the first washing, and collect the washing liquid into the washing tank for use in the next batch of fly ash pulping; Step 4: Pass clean water of the same mass as the fly ash into the filter press for a second washing, and collect the washing liquid into the washing tank for the initial washing of the next batch of fly ash. Step 5: Finally, introduce clean water of the same mass as the fly ash into the filter press for the third washing, and collect the washing liquid into the washing tank for the second washing of the next batch of fly ash. Step Six: Use 16kg / cm 2 The pressing pressure was applied to the plate and frame filter press, and after pressing for 10 minutes, water-washed fly ash with a moisture content of 25% was obtained. Step 7: Mix and stir 1 part fly ash, 1 part filtrate obtained in Step 2, and 1 part washing liquid obtained in Step 3 to obtain the second batch of slurry by weight. Step 8: Use 4kg / cm 2 The feed pump injects the second batch of slurry into the plate and frame filter press and collects the filtrate in the filtrate tank for use in the pulping of the next batch of fly ash. Step 9: First, pass a portion of the washing liquid collected in Step 4 (with the same mass as the fly ash in Step 7) into the plate and frame filter press for washing, and collect the washing liquid for pulping the next batch of fly ash. Step 10: Pass one portion of the washing liquid collected in Step 5 (with the same mass as the fly ash in Step 7) into the plate and frame filter press for washing, and collect the washing liquid for the first washing of the next batch of fly ash. Step 11: Finally, introduce clean water of the same mass as the fly ash into the plate and frame filter press for the third washing, and collect the washing liquid for the second washing of the next batch of fly ash. Step 12: Use 16kg / cm 2 The pressing pressure was applied to the plate and frame filter press, and after pressing for 10 minutes, a second batch of washed fly ash with a moisture content of 25% was obtained. Step 13: The fly ash is processed in a cyclic manner. Each subsequent batch of fly ash undergoes multi-stage water washing inside the plate and frame filter press. After the cycle is completed, the additional amount of clean water required to process each batch of fly ash is the same as the mass of fly ash being processed.

[0022] Example 2: refer to Figure 2 The online circulating water washing method for municipal solid waste incineration fly ash provided in Example 2 includes the following steps: Step 1: Mix the first batch of fly ash with water at a ratio of 1:2 and stir for 40 minutes to obtain the first batch of slurry; Step 2: Use 4kg / cm 2The feed pump injects the first batch of slurry into the plate and frame filter press and collects the filtrate in the filtrate tank for use in the next batch of fly ash pulping. Step 3: First, pass twice the weight of the fly ash into the plate and frame filter press for the first washing, and collect the washing liquid into the washing tank for use in the next batch of fly ash pulping; Step 4: Pass twice the weight of the fly ash into the plate and frame filter press for a second washing, and collect the washing liquid into the washing tank for the initial washing of the next batch of fly ash. Step 5: Use 16kg / cm 2 The pressing pressure was applied to the plate and frame filter press, and after pressing for 10 minutes, water-washed fly ash with a moisture content of 25% was obtained. Step 6: By weight, mix and stir 1 part fly ash, 1 part filtrate obtained in Step 2, and 2 parts washing liquid obtained in Step 3 to obtain the second batch of slurry; Step 7: Use 4kg / cm 2 The feed pump injects the second batch of slurry into the plate and frame filter press and collects the filtrate in the filtrate tank for use in the pulping of the next batch of fly ash. Step 8: First, pass in 2 parts of the washing liquid collected in Step 4 (i.e., twice the mass of fly ash in Step 6) for water washing, and collect the washing liquid in the washing tank for use in the pulping of the next batch of fly ash. Step 9: Add 2 parts of clean water (twice the mass of fly ash in Step 6) for washing, and collect the washing liquid in the washing tank for the next batch of fly ash washing. Step 10: Use 16kg / cm 2 The pressing pressure was applied to the plate and frame filter press, and after pressing for 10 minutes, water-washed fly ash with a moisture content of 25% was obtained. Step 11: Begin the cyclic treatment of fly ash. Each subsequent batch of fly ash will undergo multi-stage water washing inside the plate and frame filter press. After the cycle is completed, the additional amount of clean water required for each batch of fly ash treated is twice the mass of the fly ash being treated.

[0023] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0024] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0025] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An online circulating water washing method for fly ash from municipal solid waste incineration, characterized in that, The washing method uses a plate and frame filter press to circulate and wash the slurry of fly ash and water to obtain washed fly ash with a moisture content of 25%.

2. The online circulating water washing method for fly ash from municipal solid waste incineration according to claim 1, characterized in that, The online circulating water washing method includes the following steps: S101, the first batch of fly ash is mixed with water to obtain the first batch of slurry; S102, the first batch of slurry is injected into the plate and frame filter press using a feed pump, and the filtrate is collected; S103, Pass clean water into the plate and frame filter press for the first washing, and collect the first washing liquid; S104, repeatedly pass clean water into the plate and frame filter press for washing at least twice, and collect the second and third washing liquids; S105 After multiple washings, the plate and frame filter press is pressed to obtain the first batch of washed fly ash with a moisture content of 25%. S106, Weigh 1 part of fly ash, 1 part of filtrate from step S102, and 1 part of washing liquid from step S103 by mass, mix and stir to obtain the second batch of slurry; S107, repeat steps S102-S105, in S103 use the secondary washing liquid from the previous batch, in S104 use the tertiary washing liquid and clean water to obtain the second batch of water-washed fly ash with a moisture content of 25%. S108, repeat steps S106-S107 to obtain multiple batches of washed fly ash with a moisture content of 25%.

3. The online circulating water washing method for municipal solid waste incineration fly ash according to claim 2, characterized in that, In step S101, the mass ratio of fly ash to clean water is 1:

2.

4. The online circulating water washing method for fly ash from municipal solid waste incineration according to claim 2, characterized in that, In step S102, the flow rate of the feed pump is 4 kg / cm². 2 .

5. The online circulating water washing method for fly ash from municipal solid waste incineration according to claim 2, characterized in that, In steps S103 and S104, the amount of clean water added each time is 1 times the mass of fly ash.

6. The online circulating water washing method for fly ash from municipal solid waste incineration according to claim 2, characterized in that, In step S105, the pressing pressure of the plate and frame filter press is 16 kg / cm². 2 The pressing time is 10 minutes.

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