A Fenton fluidized bed rapid crystallization control system and method

Abstract

The invention discloses a Fenton fluidized bed rapid crystallization control system and method, comprising an input unit, a flow meter, a timer, a crystal row cycle unit, a reflux unit, a ferrous sulfate dosage unit and a control unit, wherein the raw water flow, crystal particle size and start-up time in the Fenton fluidized bed crystallization process are collected; the crystal row cycle is obtained according to the crystal particle size and the start-up time; the hydrogen peroxide dosing reflux volume and the ferrous sulfate dosing reflux volume are obtained according to the crystal row cycle and the raw water flow; the ferrous sulfate dosage is obtained according to the ratio of the ferrous sulfate dosage to the chemical oxygen demand and the crystal particle size; the invention not only has high dosage accuracy, but also improves the Fenton reagent dosage utilization rate.

Description

Technical Field

[0001] The invention relates to a Fenton fluidized bed rapid crystallization control system and method, belonging to the technical field of system control. Background Art

[0002] Advanced oxidation is a commonly used treatment technology for organic wastewater, especially for difficult-to-degrade industrial organic wastewater. As a pioneer of advanced oxidation technology, Fenton is a homogeneous chemical oxidation water treatment technology. Its reaction conditions are easy to obtain, and it does not require high temperature and high pressure. It has the advantages of simple equipment and rapid reaction. At present, Fenton has been widely used in the treatment of industrial wastewater such as petroleum industry, textile industry, paper industry, wood processing industry, brewing industry, and landfill leachate. The traditionally recognized Fenton chain reaction mechanism: Fenton reagent Fe 2+ and H 2 O 2 •OH generated by the reaction uses the strong oxidizing hydroxyl free radical to oxidize and decompose organic pollutants. The relevant reaction formula and its reaction rate constant are as follows:

[0003] Fe 2+ +H 2 O 2 →Fe 3+ +OH - +•OH; k1=40~80 (L·mol -1 ·s -1 ) (1)

[0004] Fe 3+ +H 2 O 2 →Fe 2+ +•O 2 H+H + ; k2 = 0.001 ~ 0.02 (L·mol -1 ·s -1 ) (2)

[0005] In the Fenton reaction, Fe 3+ Return to Fe 2+ is the rate-limiting step, and the rate constant k2 of this reaction is much lower than that of Fe 2+ Fe 3+ The conversion rate k1 will cause Fe 3+ Accumulation makes chain reaction difficult to achieve, which ultimately leads to a decrease in the degradation rate of organic matter. 2+ and H 2 O 2 The dosage of Fenton reagent can be increased to increase the concentration of hydroxyl radicals to improve the degradation rate of organic matter, but the dosage of Fenton reagent and the amount of sludge produced will be greatly increased. 2+ and H 2 O2 Both can act as hydroxyl radical scavengers to consume •OH and produce less active HO 2 •, which also leads to H 2 O 2 Ineffective decomposition reduces the utilization rate of Fenton reagent and increases the cost of wastewater treatment.

[0006] The Fenton fluidized bed system is a widely used reaction system in the Fenton oxidation process. It is a process that combines the traditional Fenton process with a fluidized bed crystallizer. The conventional fluidized bed crystallizer is a columnar reactor. Water is generally introduced from the bottom. The reactor is filled with seed material. The seed material is expanded and fluidized through internal circulation. The seed support undergoes heterogeneous crystallization during full contact with the solution, achieving the effect of removing the target substance from the wastewater. Compared with the traditional precipitation method, the crystallization product obtained by the crystallization method has a low water content, which is beneficial to the subsequent sludge treatment.

[0007] Compared with traditional Fenton, the Fenton fluidized bed has obvious advantages in organic matter removal rate and utilization rate of Fenton reagent. However, since the iron crystallization process is easily disturbed, such as reaction pH, iron ion concentration, hydraulic conditions, organic intermediates, complex interfering ions, etc., the reactor crystallization debugging time is very long, often requiring 3-6 months or even longer. There is no basis for adjusting the amount of iron salt added during the crystallization process, and it can only be judged and operated manually. The operation process consumes a lot of manpower and material resources, the crystallization efficiency is low and is not conducive to the stable operation of the Fenton organic matter oxidation reaction. There are few actual successful application cases.

[0008] How to reduce the rate-limiting effect of the fluidized bed, reduce the amount of Fenton reagent and improve the reagent utilization rate, how to intelligently control the fluidized bed crystallization process and treat water quality, and the application method of the Fenton fluidized bed that is easy to operate, low-cost, and fast in crystallization are issues that urgently need to be solved in the industrial difficult-to-degrade organic wastewater treatment industry. Summary of the invention

[0009] Purpose of the invention: In order to solve the problem that there is no basis for adjusting the amount of iron salt added during the crystallization process and the utilization rate of the Fenton reagent is low, the present invention provides a Fenton fluidized bed rapid crystallization control system and method.

[0010] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0011] A Fenton fluidized bed rapid crystallization control method comprises the following steps:

[0012] Step 1: Collect the raw water flow rate, crystal particle size and start-up time during the Fenton fluidized bed crystallization process.

[0013] Step 2: establishing a crystal arrangement cycle model according to the measured crystal particle size and start-up time, and then obtaining the crystal arrangement cycle.

[0014] Step 3, establishing a reflux model according to the crystal row cycle and the raw water flow rate, and obtaining the hydrogen peroxide dosing reflux rate and the ferrous sulfate dosing reflux rate through the reflux model.

[0015] Step 4, setting the ratio of ferrous sulfate dosage to chemical oxygen demand. A ferrous sulfate dosage model is established according to the ratio of ferrous sulfate dosage to chemical oxygen demand and the particle size of crystal particles to obtain the ferrous sulfate dosage.

[0016] Step 5, dosing hydrogen peroxide to the Fenton fluidized bed raw water according to the hydrogen peroxide dosing reflux amount obtained in step 3. Dosing ferrous sulfate to the Fenton fluidized bed raw water according to the ferrous sulfate dosing reflux amount obtained in step 3. Dosing ferrous sulfate to the Fenton fluidized bed reflux water according to the ferrous sulfate dosage obtained in step 4.

[0017] Preferably, the crystal arrangement cycle model is:

[0018] ;

[0019] in, Indicates the crystal row cycle, represents the crystal particle size, Indicates the start time.

[0020] Preferably: the reflux model is:

[0021] ;

[0022] ;

[0023] in, Indicates the amount of hydrogen peroxide added backflow, represents the raw water flow rate, Indicates the reflux rate of ferrous sulfate dosing.

[0024] Preferably: the ferrous sulfate dosage model:

[0025] ;

[0026] in, Indicates the dosage of ferrous sulfate, represents chemical oxygen demand, Indicates the ratio of ferrous sulfate dosage to chemical oxygen demand. Indicates the crystal particle size.

[0027] Preferably, the crystal particle size is measured by regular sampling.

[0028] Preferred: Before each crystal row cycle arrives sShut down the raw water pump, reflux pump and outlet valve. sOpen the raw water pump, return pump and outlet valve.

[0029] Preferred: The range is 50-70s, The range is 15-20s.

[0030] A Fenton fluidized bed rapid crystallization control system comprises an input unit, a flow meter, a timer, a crystal row cycle unit, a reflux unit, a ferrous sulfate dosage unit, and a control unit, wherein:

[0031] The input unit is used to input the crystal particle size and set the ratio of ferrous sulfate dosage to chemical oxygen demand.

[0032] The flow meter is used to measure the raw water flow in the raw water pipe.

[0033] The timer is used to time the system starting crystallization to obtain the starting time.

[0034] The crystal arrangement cycle unit is used to obtain the crystal arrangement cycle through a crystal arrangement cycle model according to the measured crystal particle diameter and the start time.

[0035] The reflux unit is used to obtain the hydrogen peroxide dosing reflux and the ferrous sulfate dosing reflux according to the crystal row cycle and the raw water flow through the reflux model.

[0036] The ferrous sulfate dosage unit is used to obtain the ferrous sulfate dosage through a ferrous sulfate dosage model according to the ratio of the ferrous sulfate dosage to the chemical oxygen demand and the particle size of the crystal particles.

[0037] The control unit performs hydrogen peroxide reflux dosing on the Fenton fluidized bed raw water according to the obtained hydrogen peroxide dosing reflux flow rate. Performs ferrous sulfate reflux dosing on the Fenton fluidized bed raw water according to the obtained ferrous sulfate dosing reflux flow rate. Performs ferrous sulfate dosing on the Fenton fluidized bed reflux water according to the obtained ferrous sulfate dosing amount.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The invention obtains a crystal row cycle by measuring the crystal particle diameter and the start-up time, obtains a hydrogen peroxide dosing reflux amount and a ferrous sulfate dosing reflux amount by the raw water flow rate during the crystal row cycle, obtains a ferrous sulfate dosing amount by the ratio of the ferrous sulfate dosing amount to the chemical oxygen demand and the crystal particle diameter, and then controls the Fenton fluidized bed, so that the dosing amounts of the hydrogen peroxide dosing reflux amount, the ferrous sulfate dosing reflux amount and the ferrous sulfate dosing amount in the crystallization process are more accurate, and the invention not only maintains the normal growth metabolic system of the crystal, but also facilitates the rapid and stable growth of the crystal, and simultaneously improves the utilization rate of the Fenton reagent amount. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the process of Fenton fluidized bed rapid crystallization control method.

[0041] Figure 2 This is the structural block diagram of the Fenton fluidized bed rapid crystallization control system. DETAILED DESCRIPTION

[0042] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0043] The present invention designs a Fenton fluidized bed rapid crystallization control method, such as Figure 1 As shown, the following steps are included:

[0044] Step 1, collecting the raw water flow, crystal particle size and start-up time during the Fenton fluidized bed crystallization process. In another embodiment, the crystal particle size is measured by regular sampling.

[0045] Step 2: establishing a crystal arrangement cycle model according to the measured crystal particle size and start-up time, and then obtaining the crystal arrangement cycle.

[0046] By removing the dimensions of crystal particle size, start-up time, and crystal row cycle, a crystal row cycle model is established:

[0047] ;

[0048] in, Indicates the crystal row cycle, represents the crystal particle size, Indicates the start time.

[0049] In another embodiment, before each crystal row cycle arrives sShut down the raw water pump, reflux pump and outlet valve. s opens the raw water pump, the reflux pump and the outlet valve. In another embodiment, The range is 50-70s, The range is 15-20s.

[0050] Step 3, establishing a reflux model according to the crystal row cycle and the raw water flow rate, and obtaining the hydrogen peroxide dosing reflux rate and the ferrous sulfate dosing reflux rate through the reflux model.

[0051] The reflux model is established by removing the dimensions of raw water flow, crystal discharge cycle, hydrogen peroxide dosing reflux and ferrous sulfate dosing reflux:

[0052] ;

[0053] ;

[0054] in, Indicates the amount of hydrogen peroxide added backflow, represents the raw water flow rate, Indicates the reflux rate of ferrous sulfate dosing.

[0055] According to different particle sizes, different reflux rates are adjusted to meet the requirements of different flow rate values ​​of hydrogen peroxide dosing reflux rate and ferrous sulfate dosing reflux rate, thereby accelerating the crystal growth rate and improving the crystal stability of the system.

[0056] Step 4, setting the ratio of ferrous sulfate dosage to chemical oxygen demand, COD refers to chemical oxygen demand. According to the ratio of ferrous sulfate dosage to chemical oxygen demand and crystal particle size, a ferrous sulfate dosage model is established to obtain the ferrous sulfate dosage.

[0057] The reflux model was established by removing the dimension by setting parameters such as the ratio of ferrous sulfate dosage to chemical oxygen demand, crystal particle size, and ferrous sulfate dosage.

[0058] The ratio of ferrous sulfate dosage to chemical oxygen demand is:

[0059] ;

[0060] in, To set the ratio of ferrous sulfate dosage to chemical oxygen demand, is the initial ferrous sulfate dosage, is the chemical oxygen demand.

[0061] After a period of reaction, the relationship between the amount of ferrous sulfate added after the reaction, the ratio of chemical oxygen demand and the crystal particle size is:

[0062] ;

[0063] in, is the ratio of ferrous sulfate dosage to chemical oxygen demand after the reaction, is the crystal particle size.

[0064] The ratio of ferrous sulfate dosage to chemical oxygen demand after the reaction is:

[0065] ;

[0066] in, for, is the amount of ferrous sulfate added after the reaction, is the chemical oxygen demand.

[0067] At this time, the amount of ferrous sulfate that needs to be increased is:

[0068] ;

[0069] ;

[0070] Then we get:

[0071] ;

[0072] in, Indicates the dosage of ferrous sulfate, represents chemical oxygen demand, Indicates the ratio of ferrous sulfate dosage to chemical oxygen demand. Indicates the crystal particle size. After the reaction, the crystal particle size gradually increases, and the amount of ferrous sulfate added gradually decreases. In general, the crystal particle size The value range is 0.2-4mm, and crystal arrangement begins when it is greater than 4mm.

[0073] Through real-time monitoring of the crystal particle size, the amount of ferrous sulfate required to supplement the reflux water is obtained based on the set ratio of ferrous sulfate dosage to chemical oxygen demand. This precise control reduces the use of ferrous sulfate dosage.

[0074] Step 5, dosing hydrogen peroxide to the Fenton fluidized bed raw water according to the hydrogen peroxide dosing reflux amount obtained in step 3. Dosing ferrous sulfate to the Fenton fluidized bed raw water according to the ferrous sulfate dosing reflux amount obtained in step 3. Dosing ferrous sulfate to the Fenton fluidized bed reflux water according to the ferrous sulfate dosage obtained in step 4.

[0075] A Fenton fluidized bed rapid crystallization control system, such as Figure 2 As shown, it includes an input unit, a flow meter, a timer, a crystal row cycle unit, a reflux unit, a ferrous sulfate dosage unit, and a control unit, wherein:

[0076] The input unit is used to input the crystal particle size, the chemical oxygen demand and to set the ratio of the ferrous sulfate dosage to the chemical oxygen demand.

[0077] The flow meter is used to measure the raw water flow in the raw water pipe.

[0078] The timer is used to time the system starting crystallization to obtain the starting time.

[0079] The crystal arrangement cycle unit is used to obtain the crystal arrangement cycle through a crystal arrangement cycle model according to the measured crystal particle diameter and the start time.

[0080] The reflux unit is used to obtain the hydrogen peroxide dosing reflux and the ferrous sulfate dosing reflux according to the crystal row cycle and the raw water flow through the reflux model.

[0081] The ferrous sulfate dosage unit is used to obtain the ferrous sulfate dosage through a ferrous sulfate dosage model according to the ratio of the ferrous sulfate dosage to the chemical oxygen demand and the particle size of the crystal particles.

[0082] The control unit performs hydrogen peroxide reflux dosing on the Fenton fluidized bed raw water according to the obtained hydrogen peroxide dosing reflux flow rate. Performs ferrous sulfate reflux dosing on the Fenton fluidized bed raw water according to the obtained ferrous sulfate dosing reflux flow rate. Performs ferrous sulfate dosing on the Fenton fluidized bed reflux water according to the obtained ferrous sulfate dosing amount.

[0083] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A Fenton fluidized bed rapid crystallization control method, characterized in that: The following steps are involved: Step 1, collecting the raw water flow rate, crystal particle size and start-up time during the Fenton fluidized bed crystallization process; Step 2, establishing a crystal arrangement cycle model according to the measured crystal particle size and start-up time, and then obtaining the crystal arrangement cycle; The crystal arrangement cycle model is: ； in, Indicates the crystal row cycle, represents the crystal particle size, Indicates the start time; Step 3, establishing a reflux model according to the crystal row cycle and the raw water flow rate, and obtaining the hydrogen peroxide dosing reflux rate and the ferrous sulfate dosing reflux rate through the reflux model; The reflux model is: ； ； in, Indicates the amount of hydrogen peroxide added backflow, represents the raw water flow rate, It indicates the reflux rate of ferrous sulfate dosing; Step 4, setting the ratio of ferrous sulfate dosage to chemical oxygen demand; establishing a ferrous sulfate dosage model according to the ratio of ferrous sulfate dosage to chemical oxygen demand and crystal particle size to obtain the ferrous sulfate dosage; Step 5, according to the hydrogen peroxide dosing reflux amount obtained in step 3, hydrogen peroxide is refluxed and dosed to the Fenton fluidized bed raw water; according to the ferrous sulfate dosing reflux amount obtained in step 3, ferrous sulfate is refluxed and dosed to the Fenton fluidized bed raw water; according to the ferrous sulfate dosage obtained in step 4, ferrous sulfate is added to the Fenton fluidized bed reflux water.

2. The Fenton fluidized bed rapid crystallization control method according to claim 1, characterized in that: The ferrous sulfate dosage model: ； in, Indicates the dosage of ferrous sulfate, represents chemical oxygen demand, Indicates the ratio of ferrous sulfate dosage to chemical oxygen demand. Indicates the crystal particle size.

3. The Fenton fluidized bed rapid crystallization control method according to claim 2, characterized in that: The crystal particle size is measured by regular sampling.

4. The Fenton fluidized bed rapid crystallization control method according to claim 3, characterized in that: Before each crystal row cycle arrives sShut down the raw water pump, reflux pump and outlet valve; after the crystal row is completed sOpen the raw water pump, return pump and outlet valve.

5. The Fenton fluidized bed rapid crystallization control method according to claim 4, characterized in that: The range is 50-70s, The range is 15-20s.

6. A Fenton fluidized bed rapid crystallization control system, characterized in that: It includes an input unit, a flow meter, a timer, a crystal row cycle unit, a reflux unit, a ferrous sulfate dosage unit, and a control unit, wherein: The input unit is used to input the crystal particle size and set the ratio of ferrous sulfate dosage to chemical oxygen demand; The flow meter is used to measure the raw water flow in the raw water pipe; The timer is used to time the system start-up crystallization to obtain the start-up time; The crystal arrangement cycle unit is used to obtain the crystal arrangement cycle through the crystal arrangement cycle model according to the measured crystal particle size and the start time; The reflux unit is used to obtain the hydrogen peroxide dosing reflux and the ferrous sulfate dosing reflux according to the crystal row cycle and the raw water flow through the reflux model; The reflux model is: ； ； in, Indicates the amount of hydrogen peroxide added backflow, represents the raw water flow rate, It indicates the reflux rate of ferrous sulfate dosing; The ferrous sulfate dosage unit is used to obtain the ferrous sulfate dosage through a ferrous sulfate dosage model according to the ratio of ferrous sulfate dosage to chemical oxygen demand and the particle size of crystal particles; The control unit performs hydrogen peroxide reflux dosing on the Fenton fluidized bed raw water according to the obtained hydrogen peroxide dosing reflux flow rate; performs ferrous sulfate reflux dosing on the Fenton fluidized bed raw water according to the obtained ferrous sulfate dosing reflux flow rate; and adds ferrous sulfate to the Fenton fluidized bed reflux water according to the obtained ferrous sulfate dosage.

7. The Fenton fluidized bed rapid crystallization control system according to claim 6, characterized in that: The ferrous sulfate dosage model: ； in, Indicates the dosage of ferrous sulfate, represents chemical oxygen demand, Indicates the ratio of ferrous sulfate dosage to chemical oxygen demand. Indicates the crystal particle size.

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