CN111348782A - Method for removing and recycling phosphorus in acetylene-cleaned waste sodium hypochlorite - Google Patents
Method for removing and recycling phosphorus in acetylene-cleaned waste sodium hypochlorite Download PDFInfo
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- CN111348782A CN111348782A CN202010260773.9A CN202010260773A CN111348782A CN 111348782 A CN111348782 A CN 111348782A CN 202010260773 A CN202010260773 A CN 202010260773A CN 111348782 A CN111348782 A CN 111348782A
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F9/00—Multistage treatment of water, waste water or sewage
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- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/20—Treatment of water, waste water, or sewage by degassing, i.e. liberation of dissolved gases
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- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
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- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
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- C02F2101/00—Nature of the contaminant
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- C02F2101/105—Phosphorus compounds
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- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
- C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
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Abstract
The invention relates to a method for removing and recycling phosphorus in acetylene cleaning waste sodium hypochlorite. The method comprises the following steps: recovering acetylene dissolved in the waste sodium hypochlorite solution by using a vacuum removal tower; 70 to 80 percent of the cooled waste sodium hypochlorite enters a sodium hypochlorite compounding system to be prepared into new sodium hypochlorite required for cleaning; and (3) the rest 20 to 30 percent of the waste sodium hypochlorite solution enters a dephosphorization procedure: feeding the waste sodium hypochlorite into an oxidation pond, adjusting the pH value to 3-5 by hydrochloric acid, adding an oxidant, reacting under stirring, and oxidizing low-valent phosphorus in the waste sodium hypochlorite to +5, so that the low-valent phosphorus exists in the form of phosphate radical ions; adding carbide slag slurry solution to form basic calcium phosphate precipitate; and (3) conveying the waste sodium hypochlorite solution to a filter press for filter pressing, using the filtrate for supplementing water for acetylene, and intensively recovering waste residues. The invention solves the problems that the total phosphorus content in the previous waste sodium hypochlorite solution is high, the total phosphorus content of slag slurry is overproof because the waste sodium hypochlorite solution is directly used for calcium carbide generation, and the sewage treatment after ash melting of soda is seriously influenced, and the waste sodium hypochlorite basically realizes 100 percent recycling; the dephosphorization process is simple and the dephosphorization efficiency is high.
Description
Technical Field
The invention relates to a method for treating acetylene purification waste sodium hypochlorite in a calcium carbide method PVC production process, in particular to a method for removing and recycling phosphorus in acetylene purification waste sodium hypochlorite.
Background
The process for producing acetylene by using calcium carbide has the advantage that the acetylene gas generated after the reaction of the calcium carbide and water contains impurity gases such as phosphine and the like due to the impurities in the calcium carbide. Phosphine is slightly soluble in water and is therefore present in large amounts in crude acetylene gas. Usually, sodium hypochlorite is used as a cleaning agent to remove phosphine in crude acetylene, a large amount of waste sodium hypochlorite solution containing phosphorus, acetylene gas and the like is generated in the process, and direct discharge can cause water body pollution and resource waste.
Therefore, there are various processing methods in the prior art. For example, in CN201310641538.6, "a method for recovering acetylene from waste sodium hypochlorite from an acetylene purifying tower", it is proposed that acetylene gas in the waste sodium hypochlorite is recovered by a vacuum pump through twice removing towers, and the treated waste sodium hypochlorite solution is directly used for preparing new sodium hypochlorite; CN201310330173.5 steam stripping system and method for cleaning waste sodium hypochlorite by acetylene in calcium carbide method, CN201410463574.2 recovery device for acetylene and method for recovering acetylene in waste sodium hypochlorite liquid, and CN201320458642.7 comprehensive utilization device for cleaning waste sodium hypochlorite by acetylene, wherein the recovery method for acetylene gas in waste sodium hypochlorite is intensively studied in the patents.
However, in the actual production process, because the waste sodium hypochlorite contains a large amount of phosphorus, if the waste sodium hypochlorite after acetylene gas removal is directly used for fresh sodium hypochlorite preparation, the cleaning system can run in an overload mode, the acetylene cleaning effect is deteriorated, and even the acetylene cleaning effect is completely failed. Therefore, in CN201220111686.8 processing system for recycling waste sodium hypochlorite and sewage, it is proposed that waste sodium hypochlorite adopts a two-stage oxidation method to remove sulfur and phosphorus pollutants in the waste sodium hypochlorite, and the waste sodium hypochlorite sequentially passes through a regulating tank, a first-stage oxidation tank, a first-stage coagulation reaction tank, a first-stage sedimentation tank, a second-stage oxidation tank, a second-stage coagulation tank, a second-stage sedimentation tank and the like. The process flow is long and complex, the types of required additives are various, the operation is complicated, and the actual requirements of PVC production cannot be met. In addition, in the prior open literature, Wanghaixia, improvement and application of a recycling process of waste sodium hypochlorite by a dry method, chlor-alkali in China, 2015 (3) and 28-30, waste sodium hypochlorite solution is used for primary salt hydrate after being treated, and in order to remove calcium plasma in the waste sodium hypochlorite, the technologies such as ceramic membrane and reverse osmosis are used, and as is known, compared with the common treatment process, the operation cost of a membrane method is high, the membrane regeneration and reverse washing consume a large amount of water, and the economy is poor.
Based on a circular economy mode, carbide slag slurry produced by acetylene cleaning is mainly used for a soda ash dissolving process, but the prior art has the following problems:
(1) the waste sodium hypochlorite solution is directly used for calcium carbide generation, so that the phosphorus content in calcium carbide slag slurry is high, and the difficulty of discharging sewage for treating phosphorus is increased after the calcium carbide slag slurry is conveyed to soda ash;
(2) current sodium hypo circulation volume is 120 meters for according to the year ~150 meters for according to the year, and effective chlorine concentration is 0.085% ~0.12%, all adopts water to dispose once for the carbide has taken place the back and has reduced the quality of water, causes the waste.
In conclusion, the research on the waste sodium hypochlorite dephosphorization technology perfects the acetylene purification process, effectively reduces the total phosphorus concentration in the sewage, and has very important significance for eliminating phosphorus pollution and protecting the water body environment.
Disclosure of Invention
The invention aims to solve the technical problem of providing a method for removing and recycling phosphorus in acetylene-cleaning waste sodium hypochlorite, which is used for intensively recovering and treating waste sodium hypochlorite solution and comprehensively treating the waste sodium hypochlorite solution through the working procedures of vacuum recovery, acidification, oxidation, neutralization, precipitation, filter pressing and the like.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a method for removing and recycling phosphorus in acetylene cleaning waste sodium hypochlorite comprises the following steps:
(1) recovering acetylene dissolved in the waste sodium hypochlorite solution by using a vacuum removal tower; the specific method comprises the following steps: pumping negative pressure at the top of the vacuum removal tower through a vacuum pump to separate acetylene gas from sodium hypochlorite, recovering the separated acetylene gas into a gas holder, and allowing the degassed liquid to flow out of the bottom and enter a cooling tower for cooling;
(2) 70 to 80 percent of the cooled waste sodium hypochlorite enters a sodium hypochlorite compounding system, namely the waste sodium hypochlorite after acetylene gas removal is directly diluted with concentrated sodium hypochlorite with 13.5 percent of available chlorine to prepare new sodium hypochlorite required for cleaning;
(3) the rest 20 to 30 percent of the waste sodium hypochlorite solution enters a dephosphorization procedure; the dephosphorization procedure comprises acidification, oxidation, neutralization, precipitation and filter pressing, wherein in the first step, degassed waste sodium hypochlorite is sent into an oxidation tank for temporary storage, hydrochloric acid is used for adjusting the pH value to 3-5, then an oxidant is added, the reaction is carried out for a certain time under the stirring action, and low-valent phosphorus in the waste sodium hypochlorite is oxidized into + 5-valent phosphorus, so that the low-valent phosphorus exists in the form of phosphate radical ions; secondly, adding a calcium carbide slurry solution, and forming basic calcium phosphate precipitate by using calcium hydroxide in the slurry and phosphate radical ions; and thirdly, pumping the neutralized and precipitated waste sodium hypochlorite solution into a filter press by using a pump for filter pressing, wherein filtrate automatically flows into a clear liquid pool for supplementing water for acetylene, and waste residues are intensively recovered due to high phosphorus content.
Compared with the prior art, the invention adopting the technical scheme has the beneficial effects that:
(1) the method solves the problems that the total phosphorus content in the previous waste sodium hypochlorite solution is high, the total phosphorus content of the slag slurry is overproof due to the direct use of the waste sodium hypochlorite solution in calcium carbide generation, and the sewage treatment after ash melting of soda is seriously influenced.
(2) The waste sodium hypochlorite solution is subjected to vacuum acetylene gas removal, temperature reduction and cooling, 70-80% of the waste sodium hypochlorite solution is directly used for fresh sodium hypochlorite preparation, 20-30% of the waste sodium hypochlorite solution enters a phosphorus removal process, and the 100% reuse rate of the waste sodium hypochlorite is basically realized.
(3) The dephosphorization process is simple, the operation difficulty is low, and the dephosphorization efficiency is high. The filter cake after filter pressing has high phosphorus content and can be used for preparing phosphate fertilizer, thus changing waste into valuable.
Further, the preferred scheme of the invention is as follows:
the dilution in the step (2) is carried out in two steps, wherein in the first step, 13.5 percent of concentrated sodium hypochlorite is diluted to 1 percent; and in the second step, the mixture is diluted from 1% to 0.085-0.12%. The system can be ensured to operate safely, and the effective chlorine concentration can be accurately controlled.
The oxidant in the step (3) is sodium hypochlorite or hydrogen peroxide.
Drawings
FIG. 1 is a process flow diagram of an embodiment of the invention.
Detailed Description
The invention is described in detail below with reference to the accompanying drawings and examples.
Referring to fig. 1, a method for removing and recycling phosphorus in acetylene purification waste sodium hypochlorite comprises the following steps:
(1) recovering acetylene dissolved in the waste sodium hypochlorite solution by using a vacuum removal tower; the content of acetylene gas in the waste sodium hypochlorite solution is about 200mg/L according to the existing working condition. And (3) pumping negative pressure at the top of the vacuum removal tower through a vacuum pump to separate acetylene gas from sodium hypochlorite, and recovering the separated acetylene gas to enter a gas holder. The degassed liquid flows out from the bottom and enters a cooling tower for cooling and cooling.
(2) 70 to 80 percent of the cooled waste sodium hypochlorite enters a sodium hypochlorite compounding system. Namely, the waste sodium hypochlorite after acetylene gas removal is directly diluted with concentrated sodium hypochlorite with 13.5 percent of available chlorine to prepare new sodium hypochlorite required for cleaning. In order to ensure the safe operation of the system and the accurate control of the effective chlorine concentration, the dilution process is carried out in two steps. The first step is to dilute 13.5 percent of concentrated sodium hypochlorite to 1 percent; and in the second step, the mixture is diluted from 1% to 0.085-0.12%.
(3) And the rest 20 to 30 percent of the waste sodium hypochlorite solution enters a phosphorus removal device. The phosphorus removal device comprises a plurality of steps of acidification, oxidation, neutralization, precipitation, filter pressing and the like. Firstly, feeding degassed waste sodium hypochlorite into an oxidation tank for temporary storage, adjusting the pH value to 3-5 by using hydrochloric acid, adding oxidants such as sodium hypochlorite or hydrogen peroxide, reacting for a certain time under the action of stirring, and oxidizing low-valent phosphorus (+ 1 valence and +3 valence) in the waste sodium hypochlorite to +5 valence so that the low-valent phosphorus exists in the form of phosphate radical ions. And secondly, adding a calcium carbide slurry solution, and forming basic calcium phosphate precipitate by using calcium hydroxide in the slurry and phosphate ions. And thirdly, pumping the neutralized and precipitated waste sodium hypochlorite solution into a filter press for filter pressing, enabling filtrate to flow into a clear liquid pool for supplementing water for acetylene, and enabling waste residues to be intensively recycled for sale (applicable to industries such as chemical fertilizers and the like) due to high phosphorus content. The whole process is centrally controlled by the DCS, and the required operators are fewer. It should be noted that: the stability of the precipitate formed by phosphate ions and calcium hydroxide solution at different pH values is different, wherein basic calcium phosphate is the most stable, so the pH value is ensured to be more than 11 in the process, and the free phosphate is prevented from being back mixed into the clear liquid.
In this example, the total phosphorus before and after the treatment of the waste sodium hypochlorite and in the supernatant of the slurry was compared, and the data is shown in table 1:
TABLE 1 Filter pressing and Total phosphorus content in the clear residue slurry
| Total phosphorus before improvement, mg/L | After improvementTotal phosphorus in mg/L | Remarks for note | |
| Sodium hypochlorite waste | 70~110 | 0~1 | Taking the pressure filtration clear liquid |
| Carbide slag slurry supernatant | 10~15 | 1~3 |
As can be seen from Table 1, the total phosphorus content in the supernatant of the carbide slag slurry is reduced obviously, and the total phosphorus content meets the relevant requirements in GB15581-2016 emission Standard of pollutants for caustic soda and polyvinyl chloride industries.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions of the present invention are equivalent to or changed by the present invention.
Claims (3)
1. A method for removing and recycling phosphorus in acetylene cleaning waste sodium hypochlorite is characterized by comprising the following steps: the method comprises the following steps:
(1) recovering acetylene dissolved in the waste sodium hypochlorite solution by using a vacuum removal tower; the specific method comprises the following steps: pumping negative pressure at the top of the vacuum removal tower through a vacuum pump to separate acetylene gas from sodium hypochlorite, recovering the separated acetylene gas into a gas holder, and allowing the degassed liquid to flow out of the bottom and enter a cooling tower for cooling;
(2) 70 to 80 percent of the cooled waste sodium hypochlorite enters a sodium hypochlorite compounding system, namely the waste sodium hypochlorite after acetylene gas removal is directly diluted with concentrated sodium hypochlorite with 13.5 percent of available chlorine to prepare new sodium hypochlorite required for cleaning;
(3) the rest 20 to 30 percent of the waste sodium hypochlorite solution enters a dephosphorization procedure; the dephosphorization procedure comprises acidification, oxidation, neutralization, precipitation and filter pressing, wherein in the first step, degassed waste sodium hypochlorite is sent into an oxidation tank for temporary storage, hydrochloric acid is used for adjusting the pH value to 3-5, then an oxidant is added, the reaction is carried out for a certain time under the stirring action, and low-valent phosphorus in the waste sodium hypochlorite is oxidized into + 5-valent phosphorus, so that the low-valent phosphorus exists in the form of phosphate radical ions; secondly, adding a calcium carbide slurry solution, and forming basic calcium phosphate precipitate by using calcium hydroxide in the slurry and phosphate radical ions; and thirdly, pumping the neutralized and precipitated waste sodium hypochlorite solution into a filter press by using a pump for filter pressing, wherein filtrate automatically flows into a clear liquid pool for supplementing water for acetylene, and waste residues are intensively recovered due to high phosphorus content.
2. The method for removing and recycling phosphorus in acetylene purification waste sodium hypochlorite according to claim 1, which is characterized in that: the dilution in the step (2) is carried out in two steps, wherein in the first step, 13.5 percent of concentrated sodium hypochlorite is diluted to 1 percent; and in the second step, the chlorine concentration is diluted from 1% to 0.085-0.12%, so that the system operation safety can be ensured, and the effective chlorine concentration can be accurately controlled.
3. The method for removing and recycling phosphorus in acetylene purification waste sodium hypochlorite according to claim 1, which is characterized in that: the oxidant in the step (3) is sodium hypochlorite or hydrogen peroxide.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111763132A (en) * | 2020-07-09 | 2020-10-13 | 唐山三友氯碱有限责任公司 | Sodium hypochlorite acidification method for acetylene purification process |
| CN112221298A (en) * | 2020-08-22 | 2021-01-15 | 山东鲁泰化学有限公司 | Comprehensive recycling method for acetylene waste sodium hypochlorite |
| CN113402068A (en) * | 2021-07-01 | 2021-09-17 | 宁夏金昱元高新材料有限公司 | Method for recycling acetylene purification waste sodium hypochlorite |
| CN113481028A (en) * | 2021-07-02 | 2021-10-08 | 宁夏金昱元高新材料有限公司 | Method for cleaning waste sodium hypochlorite by acetylene of calcium carbide method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103130369A (en) * | 2011-12-05 | 2013-06-05 | 天辰化工有限公司 | Method of reusing sodium hypochlorite waste water generated by acetylene lustration |
| CN203360208U (en) * | 2013-07-30 | 2013-12-25 | 广西德陆科技有限公司 | Waste sodium hypochlorite comprehensive utilization device used during acetylene cleaning |
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2020
- 2020-04-03 CN CN202010260773.9A patent/CN111348782A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103130369A (en) * | 2011-12-05 | 2013-06-05 | 天辰化工有限公司 | Method of reusing sodium hypochlorite waste water generated by acetylene lustration |
| CN203360208U (en) * | 2013-07-30 | 2013-12-25 | 广西德陆科技有限公司 | Waste sodium hypochlorite comprehensive utilization device used during acetylene cleaning |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111763132A (en) * | 2020-07-09 | 2020-10-13 | 唐山三友氯碱有限责任公司 | Sodium hypochlorite acidification method for acetylene purification process |
| CN111763132B (en) * | 2020-07-09 | 2023-07-18 | 唐山三友氯碱有限责任公司 | Sodium hypochlorite acidification method for acetylene cleaning process |
| CN112221298A (en) * | 2020-08-22 | 2021-01-15 | 山东鲁泰化学有限公司 | Comprehensive recycling method for acetylene waste sodium hypochlorite |
| CN113402068A (en) * | 2021-07-01 | 2021-09-17 | 宁夏金昱元高新材料有限公司 | Method for recycling acetylene purification waste sodium hypochlorite |
| CN113481028A (en) * | 2021-07-02 | 2021-10-08 | 宁夏金昱元高新材料有限公司 | Method for cleaning waste sodium hypochlorite by acetylene of calcium carbide method |
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