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Precise control method for sequencing batch neutralization of concentrated acid wastewater in photovoltaic industry

A control method and batch-sequencing technology, which is applied in water treatment parameter control, chemical instruments and methods, control/manipulation systems, etc., can solve problems such as easily damaged equipment, severe acid-base neutralization reactions, and drug packaging, and achieve saving Operating cost, preventing the pH from rising too high, and preventing incomplete fluoride removal

Inactive Publication Date: 2019-09-20
JIANGSU NJU ENVIRONMENTAL TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Aiming at the problem in the prior art that during the treatment of concentrated acid wastewater in the photovoltaic industry, due to the severe acid-base neutralization reaction, the medicine is wrapped and the equipment is easily damaged due to the intense exothermic effect, the present invention provides a method to adjust the dosage of medicine according to the pH value of the wastewater. Sequential batch type, small water volume neutralization control method

Method used

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  • Precise control method for sequencing batch neutralization of concentrated acid wastewater in photovoltaic industry

Examples

Experimental program
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Effect test

Embodiment 1

[0043] Take 1L of strong acid waste liquid from the photovoltaic industry, the HF content in the waste water is 30%, the fluorine ion concentration is 15g / L, and the HNO 3 The content is 10%, in addition to a small amount of HCl and H 2 SO 4 , after testing, the H in the wastewater + The concentration is about 18mol / L, and the pH is far greater than 1mol / L.

[0044] When the waste water H + When the concentration is greater than 1mol / L, according to the formula M1=60*(C H + -1) Calculate and get CaCO 3 The absolute amount of dosage is 1020g / L, that is, kg / m 3 , during the dosing process with a mass concentration of 40% CaCO 3 Dosing in the form of slurry, stirring during the dosing process, the residence time is 2h, and the pH is 0.5 after the reaction is complete;

[0045] When wastewater 0-pH -0.001) calculation, get CaCO 3 The absolute amount of dosage is 18.91g / L, that is, kg / m 3 , during the dosing process with a mass concentration of 40% CaCO 3 Dosing in the f...

Embodiment 2

[0051] Take 1L of waste acid solution from the photovoltaic industry, the pH of the waste acid solution is 1.5, and the main components of the waste acid are HF and HNO 3 , HCl and H 2 SO 4 etc., wherein the concentration of fluoride ion is 8g / L.

[0052] First, when the waste water is 0-Ph -0.001) calculation, get CaCO 3 The absolute amount of dosing is 1.84g / L, and it is added in the form of a slurry with a mass concentration of 40% during the dosing process, stirred during the dosing process, the residence time is 1h, and the pH is 3.0 after the reaction is complete;

[0053] Then, according to the calculation formula M of 3Ca(OH)2 =45*10 -pH ,M CaCl2 =3*C F- -M1-M2, where M1=0, M2=1.84g / L, after calculation, Ca(OH) 2 Dosing absolute amount is 0.045g / L, CaCl 2 The absolute amount of dosage is 22.16g / L. Ca(OH) 2 Dosing in the form of a slurry with a mass concentration of 40% during the dosing process, CaCl 2 Dosing in the form of a slurry with a mass concentration ...

Embodiment 3

[0055] Take 1L of waste acid solution from the photovoltaic industry, the pH of the waste acid solution is 4, and the main components of the waste acid are HF and HNO 3 , HCl and H 2 SO 4 etc., wherein the concentration of fluoride ion is 0.6g / L.

[0056] According to the calculation formula M of 3Ca(OH)2 =45*10 -pH ,M CaCl2 =3*C F- -M1-M2, calculated, Ca(OH) 2 Dosing absolute amount is 0.005g / L, CaCl 2 The absolute amount of dosage is 1.8g / L. Ca(OH) 2 Dosing in the form of a slurry with a mass concentration of 40% during the dosing process, CaCl 2 Dosing in the form of a slurry with a mass concentration of 50% during the dosing process, stirring during the dosing process, the residence time is 1h, and the pH is above 7 after the reaction is complete.

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Abstract

Belonging to the field of wastewater treatment, the invention discloses a precise control method for sequencing batch neutralization of concentrated acid wastewater in photovoltaic industry. The method includes the steps of: when the pH of the wastewater is less than or equal to 3, carrying out the following steps of: a) adding CaCO3 as a neutralizing reagent into the wastewater for neutralization reaction, and adjusting the pH value of the wastewater to 3 (with the pH less than or equal to 7); and b) adding Ca(OH)2 firstly into the wastewater treated by step 1), then adding CaCl2 for neutralization reaction; when the pH of the wastewater is greater than 3 and smaller than or equal to 7, adding Ca(OH)2 and CaCl2 directly into the wastewater for neutralization and defluorination reaction. The sequencing batch and small water volume neutralization control method regulating reagent adding according to the pH value of wastewater provided by the invention overcomes the problems of low reaction efficiency caused by reagent wrapping due to violent acid-base neutralization reaction and easy equipment damage due to exothermic effect in the concentrated acid wastewater treatment process in photovoltaic industry.

Description

technical field [0001] The invention relates to a control method for the neutralization treatment of concentrated acid waste liquid produced in the photovoltaic industry, and belongs to the field of wastewater treatment. Background technique [0002] Solar photovoltaic energy is green energy, but there is serious pollution in the production process of photovoltaic industry, especially the production of photovoltaic cells, among which the discharge of water pollutants cannot be ignored. Environmental protection is the biggest constraint factor for the development of photovoltaic industry. The photovoltaic industry is divided into upstream, midstream and downstream according to different production products. The upstream industry mainly produces monocrystalline silicon and polycrystalline silicon wafers, the midstream industry mainly uses single / polycrystalline silicon wafers to produce solar cells, and the downstream industry mainly produces photovoltaic power generation syste...

Claims

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Application Information

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IPC IPC(8): C02F1/66C02F1/58
CPCC02F1/008C02F1/583C02F1/66C02F2209/02C02F2209/06
Inventor 汪林张炜铭吕振华高亚娟李丽芳唐凯黄如全马信牛志华
Owner JIANGSU NJU ENVIRONMENTAL TECH
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