CN102689975A - Resourceful treatment method for high-salinity wastewater - Google Patents

Abstract

The invention discloses a resourceful treatment method for high-salinity wastewater, comprising the following steps of: removing organic pollutants of organic high-salinity waste water by adopting a catalysis wet-type peroxide oxidation method; and oxidizing the content of total organic carbon (TOC) of the high-salinity wastewater to be below a maximum limit value of salt water which flows into an electrolytic cell of a chloralkali plant, so that the high-salinity waste water subjected to the catalysis wet-type peroxide oxidation treatment can be used as a raw material for producing chlorine and caustic soda in the chloralkali plant, so that resourceful utilization of the high-salinity wastewater can be realized.

Description

The high-salt wastewater recycling processing method

Technical field

The present invention relates to technical field of waste water processing, more particularly, relate to a kind of catalytic wet peroxide oxidation technology of high salt organic waste water.

Background technology

In the production process of products such as epoxy chloropropane, epoxy resin, vinylidene chloride, vanillin food grade,1000.000000ine mesh, Hydrazine Hydrate 80 and careless glycosides phosphine, can produce the organic waste water (abbreviation high-salt wastewater) that contains high density chlorination sodium in a large number.For example, waste water total organic carbon (TOC) concentration that produces when producing epoxy chloropropane with the glycerine method is about 1500mg/L, and the sodium-chlor mass percentage concentration is about 20%; With 1,1, waste water TOC that produces when 2-trieline and sodium hydroxide production vinylidene chloride and sodium chloride concentration are respectively about 4500mg/L with about 20%.

For high-salt wastewater; Domestic relevant enterprise adopts the biochemical method of dilution to handle mostly; Yet because sodium chloride concentration often need consume the fresh water that is equivalent to tens times of wastewater volume up to about 20% when therefore handling this type of waste water with the dilution biochemical process in many high-salt wastewaters, this has not only wasted a large amount of Freshwater resources; But also increased considerably discharged waste water, do not meet the disposal of pollutants policy of country.

Domestic also have part enterprise with the method for multiple-effect evaporation desalination high-salt wastewater to be carried out pre-treatment earlier, and then handle the water of condensation of multiple-effect evaporation through biochemical process.Method with the multiple-effect evaporation desalination is carried out pre-treatment to high-salt wastewater; Maximum obstacle is that the salt that crystallization is separated out does not have suitable outlet; Reason is often to contain a large amount of organic pollutants in the crystallization salt of separating out, and can not use as general industrial salt, and in most of the cases this salt can only be regarded as hazardous solid waste; Must entrust has the unit of qualification to carry out harmlessness disposing, and disposal costs is quite high.

The maximum purposes of Industrial Salt (sodium-chlor) is to produce the raw material of chlorine and caustic soda as chlor-alkali plant.The electrolytic technology of sodium chloride aqueous solution (being commonly called as salt solution or bittern) mainly contains two types, and one type is electrolysis with ion-exchange film, and another kind of is diaphragm electrolysis.Electrolysis with ion-exchange film can obtain 30% sodium hydroxide, and diaphragm electrolysis can only obtain 10% sodium hydroxide.But electrolysis with ion-exchange film is higher than diaphragm electrolysis to advancing groove brinish water quality requirement, and advancing groove brinish TOC index with electrolyzer is example, and ion-exchange membrane electrolyzer requires into the groove salt solution TOC must be less than 10mg/L, and diaphragm sell requires into groove brinish TOC less than 200mg/L.If can drop to 200mg/L to the TOC of high-salt wastewater or below the 10mg/L, just can produce high-salt wastewater as chlor-alkali plant the raw material use of chlorine and caustic soda through appropriate means.

In addition, also have minority enterprise to adopt methods such as wet oxidation, CWO and burning to handle high-salt wastewater in developed country, but the investment of these methods and working cost are all very high, domestic enterprise is difficult to bear mostly.

Summary of the invention

Technical problem to be solved by this invention is; Provide a kind of and remove contained organic pollutant in the high-salt wastewater, make its TOC concentration be lower than the high-salt wastewater recycling processing method that the chlor-alkali plant electrolyzer advances groove salt solution TOC limit value through catalytic wet peroxide oxidation method.

In order to address the above problem, the invention provides a kind of high-salt wastewater recycling processing method, remove contained organic pollutant in the high-salt wastewater through catalytic wet peroxide oxidation method, it is characterized in that, comprise the steps:

(1) using hydrochloric acid to regulate waste water ph is 1.5-4.0, and temperature of reaction is 70-95 ℃;

(2) take by weighing an amount of oxygenant and catalyzer, said oxygenant is hydrogen peroxide (ydrogen peroxide 50), and dosage is 0.2-0.4mol-H ₂O ₂/ g-TOC, the corresponding 0.2-0.4molH that adds of promptly every gram TOC ₂O ₂Said catalyzer is iron protochloride or ferrous sulfate, and dosage is 12-36mmol/L;

(3) mode that slow dropping oxidizing agent and catalyzer, oxygenant adopt in batches slowly dropping or slow continuously stream to add adds, and in 1-6 hours, adds to finish; Catalyzer also adopts slowly to drip in batches or slowly flow the mode that adds continuously and adds, and in 1-6 hour, adds to finish; Since the dropping oxidizing agent first time; Every pH value of measuring primary first-order equation liquid at a distance from 5-30min; And the pH value of control reaction solution perhaps passes through the adding of pH automatic controlling system hydrochloric acid or sodium hydroxide at 2.5-3.5, and the pH value stabilization that makes reaction solution is at 2.5-3.5;

(4) treat oxygenant and catalyzer all add finish after; Continue reaction 15-180min; Yet transfer to neutrality or slight alkalinity to the pH value of reaction solution with sodium hydroxide, precipitate or remove by filter catalyzer, sedimentary supernatant or filtrating promptly can be used as the raw material use that electrolytic process is produced chlorine and caustic soda.

The slow dropping of step (3) oxygenant and catalyzer is a key point, carries out through following formula:

1) oxygenant dosing method:

The volume of supposing high-salt wastewater is V _W(L), the TOC concentration of high-salt wastewater is TOC before the oxide treatment ₀Oxygenant (ydrogen peroxide 50) amount that need add when (g/L), then handling this waste water with catalytic wet superoxide method is:

M _HP＝(0.2~0.4)×（TOC ₀×V _W） （1）

In the formula: M _HP-ydrogen peroxide 50 the total amount (mol) that need add,

Ydrogen peroxide 50 mole number (the mol-H that (0.2 ~ 0.4)-removal 1g TOC needs ₂O ₂/ g-TOC),

TOC ₀The TOC concentration (g/L) of high-salt wastewater before the-oxide treatment,

V _WThe volume of-water (L);

For ease of using, with M _HPConvert volume to, calculating formula is following:

$V_{\mathrm{HP}}=\frac{M_{\mathrm{HP}}\×34}{1100}\×\frac{100}{C_{\mathrm{HP}}}=(0.62~1.24){\mathrm{TOC}}_0\·V_W/C_{\mathrm{HP}}---\left(2\right)$

In the formula: V _HPThe TV (L) of-ydrogen peroxide 50 that need add,

The molar mass of 34-ydrogen peroxide 50 (g/mol),

The approximation of 1100-ydrogen peroxide 50 density (g/L),

C _HPThe mass percentage concentration of-ydrogen peroxide 50 (%);

The 1-6 hour time that adds that ydrogen peroxide 50 is total, the dioxygen water yield that then average PM adds is:

$v_{\mathrm{HP}}=\frac{V_{\mathrm{HP}}\×1000}{(1~6)\×60}\≈(1.7~20.6){\mathrm{TOC}}_0\·V_W/C_{\mathrm{HP}}---\left(3\right)$

In the formula: v _HP-ydrogen peroxide 50 volume (mL/min) that average PM adds.

★ then drips (or stream adds) by the speed shown in the formula (3) continuously if ydrogen peroxide 50 is continuous dropping (or stream adds);

If ★ intermittently drips, every separated (1-15) min drips once, and then average each amount that drips is:

q _HP＝(1.7-309.0)TOC ₀·V _W/C _HP (4)

Q in the formula _HP-average each ydrogen peroxide 50 volume (mL/ time) that drips.

2) catalyzer dosing method:

The volume of supposing waste water is V _WThe catalytic amount that (L), then need add is:

M _CFe＝(12~36)×V _w (5a)

M _CCu＝(0~3)×V _w (5b)

In the formula: M _CFe-catalyzer (iron protochloride or the ferrous sulfate) total amount (mmol) that need add,

The catalyzer that (12 ~ 36)-every liter waste water need add (iron protochloride or ferrous sulfate) amount (mmol/L),

M _CCu-catalyzer (cupric chloride or the copper sulfate) amount (mmol) that need add,

The catalyzer that (0 ~ 3)-every liter waste water need add (cupric chloride or copper sulfate) amount (mmol/L),

V _wThe volume of-waste water (L);

The time of adding always of catalyzer is 1 ~ 6 hour, and the catalytic amount that then average PM adds is:

$m_C=\frac{M_{\mathrm{CFe}}}{(1~6)\×60}=(0.033~0.60)V_W---\left(6\right)$

In the formula: m _C-catalytic amount (mmol/min) that average PM adds.

Cupric chloride (copper sulfate) directly mixes with iron protochloride (or ferrous sulfate) by formula (5b) calculated amount, adds after both are water-soluble in the lump, when calculating PM or the catalytic amount that at every turn adds, can not consider cupric chloride (copper sulfate).For ease of adding of catalyzer, become catalyst preparation 1 ~ 3mol/L (with Fe usually ²⁺Meter) the aqueous solution adds after can certainly becoming the aqueous solution of other concentration to catalyst preparation.Because the uncertainty of the catalyst concn of preparing, the volume of the aqueous catalyst solution that causes being prepared is also uncertain, so this specification sheets is still with mmol/L or represent the dosage of catalyzer for mmol/ time.

The time of adding always of catalyzer is 1-6 hour, and the catalytic amount that then average PM adds is:

★ then drips (or stream adds) by the speed shown in the formula (6) continuously if aqueous catalyst solution is continuous dropping (or stream adds);

If ★ intermittently drips, every separated (1 ~ 15) min drips once, and then average each amount that drips is:

q _C＝(1~15)m _C＝(0.033~9.00)V _W (7)

In the formula: q _CThe each catalytic amount (mmol/ time) that drips of---average.

Be that the slow continuously stream oxidizer of step (3) is meant that the oxygenant volume that average PM adds is (1.7 ~ 20.6) TOC ₀V _W/ C _HPMilliliter (is annotated: TOC ₀The TOC concentration of high-salt wastewater before the-oxide treatment, g/L; V _WThe volume of-high-salt wastewater, L; C _HPThe mass percentage concentration of-ydrogen peroxide 50, %, down together.), slow continuously stream adds catalyzer and is meant, and the catalytic amount that average PM adds is (0.033 ~ 0.60) V _WMmole; Slowly dropping oxidizing agent is meant in batches, whenever drips once at a distance from 1-15min, and average each amount that drips is (1.7 ~ 309.0) TOC ₀V _W/ C _HPMilliliter; Slowly drip catalyzer in batches and be meant, the catalytic amount that on average at every turn adds is (0.033 ~ 9.00) V _WMmole.

As a preferred version, the said catalyzer of step (2) can also have cupric chloride or copper sulfate, and dosage is not for being higher than 3mmol/L.In iron protochloride, mix a spot of cupric chloride or copper sulfate and can improve the effect of catalytic wet peroxide oxidation.

In order to reduce the running cost of high-salt wastewater recycling treatment; Can be according to the concentration and the character (like volatile and wetting ability etc.) of contained organic pollutant in the high-salt wastewater; Before the catalytic wet peroxide oxidation; Earlier high-salt wastewater is carried out pre-treatment, also can after the catalytic wet peroxide oxidation, further purify high-salt wastewater through active carbon adsorption with methods such as stripping, charcoal absorptions.

The invention has the advantages that; The invention discloses a kind of haline water resource treatment technique; Promptly remove contained organic pollutant in the high-salt wastewater through catalytic wet peroxide oxidation method; Optimize the dosage and the dosing method of catalyzer and oxygenant; Especially slowly drip through catalyzer and oxygenant in batches or continuously, make the waste water TOC concentration of processing be lower than the chlor-alkali plant electrolyzer and advance groove brinish TOC limit value, so just can be with the raw material use of the high-salt wastewater of handling as chlor-alkali plant production chlorine and caustic soda; Realize the recycling of high-salt wastewater and the zero release of waste water, protection water surrounding and the Sustainable development that promotes relevant industries are had crucial meaning.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.Employed experimental technique is ordinary method like no specified otherwise among the following embodiment.Used material, reagent etc. like no specified otherwise, all can obtain from commercial sources among the following embodiment.Should be understood that these embodiment only to be used to the present invention is described and be not used in the restriction scope of the present invention.

Embodiment 1

Step 1: with hydrochloric acid epoxy chloropropane waste water (TOC=1620mg/L; NaCl=21.5%) pH value is transferred to 3.0; Then 800mL was regulated in three mouthfuls of round-bottomed flasks of water sample adding 1000mL of pH, and there-necked flask was placed 90 ℃ water bath with thermostatic control again, the mouth in the centre of there-necked flask is equipped with stirring rod; Slotting pH electrode of two mouths also has one as dosing mouth in addition.Open mechanical stirring, the preheating water sample.

Step 2: take by weighing iron protochloride (FeCl ₂4H ₂O) 4.3g (about 21.6mmol) is dissolved in it in 10mL water, as catalyzer then; Get the hydrogen peroxide (about 0.44mol) of 45mL 30% with graduated cylinder, as oxygenant.

Step 3: when the temperature of water sample in the there-necked flask and bath temperature are basic identical; Drip the 0.5mL catalyzer from dosing mouth; Slowly drip the 1mL oxygenant simultaneously; Every then at a distance from catalyzer of 3min dropping and oxygenant, both dripping quantity are respectively 0.5mL and 1mL, all drip off until catalyzer and oxygenant.Since the dropping oxidizing agent first time, every separated 10min measures the pH value of primary first-order equation liquid, and is controlled at 2.5-3.5 to the pH value of reaction solution with hydrochloric acid or sodium hydroxide.

Step 4: catalyzer and oxygenant all drip, and after continuing stirring reaction 60min, are adjusted to 7.5 to reacting liquid pH value with sodium hydroxide, staticly settle, and measure the TOC of supernatant.

TOC measures and the result is 96mg/L, meets diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

Embodiment 2

Step 1: except that bath temperature is 80 ℃, other are all with embodiment 1.

Step 2-step 4: with embodiment 1.

TOC measures and the result is 128mg/L, meets diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

Embodiment 3

Step 1: with embodiment 2.

Step 2: take by weighing iron protochloride (FeCl ₂4H ₂O) 4.3g (about 21.6mmol) and cupric chloride (CuCl ₂2H ₂O) 0.1g (about 0.06mmol), and both are mixed, the mixture with both is dissolved in the 10mL water, as catalyzer then; Get the hydrogen peroxide (about 0.44mol) of 45mL 30% with graduated cylinder, as oxygenant.

The step gather three with step 4 with embodiment 1.

It is 90mg/L that TOC measures the result, meets diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

Comparing embodiment 2 and 3 can be found out, in iron protochloride, mixes the effect that a spot of cupric chloride can improve the catalytic wet peroxide oxidation.

Embodiment 4

Step 1: with embodiment 1.

Step 2: take by weighing ferrous sulfate (FeSO ₄7H ₂O) 6.0g (about 21.6mmol) is dissolved in it in 10mL water, as catalyzer then; Get the hydrogen peroxide (about 0.44mol) of 45mL 30% with graduated cylinder, as oxygenant.

The step gather three with step 4 with embodiment 1.

It is 93mg/L that TOC measures the result, also meets diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.But when using ferrous sulfate to make catalyzer, the sulfate ion in the catalyzer will all remain in the high-salt wastewater after reaction finishes, may be unfavorable to follow-up electrolysis, so the most handy iron protochloride is made catalyzer on the engineering.

Embodiment 5

Step 1: with embodiment 1.

Step 2: with embodiment 1.

Step gathers three: when the temperature of water sample in the there-necked flask and bath temperature are basic identical, successively with catalyzer and the disposable adding reaction flask of oxygenant, continue stirring reaction 240min from dosing mouth then.In reaction process, every separated 10min measures the pH value of primary first-order equation liquid, and is controlled at 2.5-3.5 to the pH value of reaction solution with hydrochloric acid or sodium hydroxide.

Step 4: reaction is adjusted to 7.5 to reacting liquid pH value with sodium hydroxide after finishing, and staticly settles, and measures the TOC of supernatant.

It is 895mg/L that TOC measures the result, does not meet diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

Embodiment 6

Step 1: with embodiment 1.

Step 2: with embodiment 1.

Step gathers three: when the temperature of water sample in the there-necked flask and bath temperature are basic identical; From the dosing mouth handle disposable adding reaction flask of catalyzer for preparing; Slowly drip the 1mL oxygenant simultaneously, every then separated 3min drips the 1mL oxygenant, all drips off until oxygenant.Since the dropping oxidizing agent first time, every separated 10min measures the pH value of primary first-order equation liquid, and is controlled at 2.5-3.5 to the pH value of reaction solution with hydrochloric acid or sodium hydroxide.

Step 4: with embodiment 1.

It is 286mg/L that TOC measures the result, does not meet diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

Compare the result of embodiment 5,6 with the result of embodiment 1, can see clearly that the dosing method of the dosing method of catalyzer and oxygenant, particularly oxygenant is very big to the influential effect of catalytic wet peroxide oxidation.

Embodiment 7

Step 1: with the pretreated vinylidene chloride waste water of hydrochloric acid handle process stripping (TOC=285mg/L; NaCl=20.3%) pH value is transferred to 3.5; Then 800mL was regulated in three mouthfuls of round-bottomed flasks of water sample adding 1000mL of pH, and there-necked flask was placed 90 ℃ water bath with thermostatic control again, the mouth in the centre of there-necked flask is equipped with stirring rod; Slotting pH electrode of two mouths also has one as dosing mouth in addition.Open mechanical stirring, the preheating water sample.

Step 2: take by weighing iron protochloride (FeCl ₂4H ₂O) 3.2g is dissolved in it in 10mL water, as catalyzer then; Get the hydrogen peroxide of 10mL 30% with graduated cylinder, as oxygenant.

Step 3: when the temperature of water sample in the there-necked flask and bath temperature are basic identical; Drip the 1mL catalyzer from dosing mouth, the while slowly drips the 1mL oxygenant, and is every then at a distance from catalyzer of 15min dropping and oxygenant; Both dripping quantity are 1mL, all drip off until catalyzer and oxygenant.Since the dropping oxidizing agent first time, every separated 10min measures the pH value of primary first-order equation liquid, and is controlled at 2.5-3.5 to the pH value of reaction solution with hydrochloric acid or sodium hydroxide.

Step 4: with embodiment 1.

It is 22mg/L that TOC measures the result, meets diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

Step 5: be transferred to 2.0 to the pH value of 500mL supernatant with hydrochloric acid, add the 0.1g Powdered Activated Carbon then, behind the stirring 120min, filter, record the TOC=4mg/L of filtrating, meet electrolysis with ion-exchange film and advance the groove salt solution TOC < requirement of 10mg/>L.

Embodiment 8

Step 1: with the pretreated Hydrazine Hydrate 80 waste water of hydrochloric acid handle process stripping (TOC=316mg/L; NaCl=6.3%) pH value is transferred to 3.5; Then 800mL was regulated in three mouthfuls of round-bottomed flasks of water sample adding 1000mL of pH, and there-necked flask was placed 90 ℃ water bath with thermostatic control again, the mouth in the centre of there-necked flask is equipped with stirring rod; Slotting pH electrode of two mouths also has one as dosing mouth in addition.Open mechanical stirring, the preheating water sample.

Step 2: take by weighing iron protochloride (FeCl ₂4H ₂O) 2.5g is dissolved in it in 10mL water, as catalyzer then; Get the hydrogen peroxide of 10mL 30% with graduated cylinder, as oxygenant.

Step 3: with embodiment 7.

Step 4: with embodiment 1.

It is 58mg/L that TOC measures the result, meets diaphragm sell and advances the groove salt solution TOC < requirement of 200mg/>L.

The above only is a preferred implementation of the present invention; Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; Can also make some improvement and retouching, these improvement and retouching also should be regarded as protection scope of the present invention.

Claims (4)

1. a high-salt wastewater recycling processing method is removed contained organic pollutant in the high-salt wastewater through catalytic wet peroxide oxidation method, it is characterized in that, comprises the steps:

(1) using hydrochloric acid to regulate waste water ph is 1.5-4.0, and temperature of reaction is 70-95 ℃;

(2) take by weighing an amount of oxygenant and catalyzer, said oxygenant is a hydrogen peroxide, and dosage is 0.2-0.4mol-H ₂O ₂/ g-TOC; Said catalyzer is iron protochloride or ferrous sulfate, and dosage is 12-36mmol/L;

(3) mode that slow dropping oxidizing agent and catalyzer, oxygenant adopt in batches slowly dropping or slow continuously stream to add adds, and in 1-6 hours, adds to finish; Catalyzer also adopts slowly to drip in batches or slowly flow the mode that adds continuously and adds, and in 1-6 hours, adds to finish; Since the dropping oxidizing agent first time, every pH value at a distance from 5-30min mensuration primary first-order equation liquid, the pH value of control reaction solution is at 2.5-3.5;

(4) treat oxygenant and catalyzer all add finish after; Continue reaction 15-180min; Yet transfer to neutrality or slight alkalinity to the pH value of reaction solution with sodium hydroxide, precipitate or remove by filter catalyzer, sedimentary supernatant or filtrating promptly can be used as the raw material use that electrolytic process is produced chlorine and caustic soda.

2. a kind of high-salt wastewater recycling processing method according to claim 1 is characterized in that, step (3) slowly flows oxidizer continuously and is meant that the hydrogen peroxide volume that average PM adds is (1.7 ~ 20.6) TOC ₀V _W/ C _HPMilliliter, said TOC ₀The TOC concentration of high-salt wastewater before the-oxide treatment, g/L; V _WThe volume of-high-salt wastewater, L; C _HPThe mass percentage concentration of-ydrogen peroxide 50, %; Slow continuously stream adds catalyzer and is meant, the catalytic amount that average PM adds is (0.033 ~ 0.60) V _WMmole.

3. a kind of high-salt wastewater recycling processing method according to claim 1 is characterized in that, the slow in batches dropping oxidizing agent of step (3) is meant that whenever drip once at a distance from 1-15min, the amount of average each dropping is (1.7 ~ 309.0) TOC ₀V _W/ C _HPMilliliter; Slowly drip catalyzer in batches and be meant, average each catalytic amount that drips is (0.033 ~ 9.00) V _WMmole.

4. a kind of high-salt wastewater recycling processing method according to claim 1 is characterized in that, the said catalyzer of step (2) also has cupric chloride or copper sulfate, and dosage is not for being higher than 3mmol/L.