CN102689975B - 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 the products such as epoxy chloropropane, epoxy resin, vinylidene chloride, vanillin food grade,1000.000000ine mesh, hydrazine hydrate and careless glycosides phosphine, can produce a large amount of organic waste water (abbreviation high-salt wastewater) containing high density chlorination sodium.For example, waste water total organic carbon (TOC) concentration produced during with producing epoxy chloropropane through glycerine method is about 1500mg/L, and the sodium-chlor mass percentage concentration is about 20%; The waste water TOC produced during with 1,1,2-trieline and sodium hydroxide production vinylidene chloride and sodium chloride concentration are respectively 4500mg/L left and right and 20% left and right.

For high-salt wastewater, domestic relevant enterprise adopts the biochemical method of dilution to be processed mostly, yet due to sodium chloride concentration in many high-salt wastewaters up to 20% left and right, often need to consume the fresh water that is equivalent to tens times of wastewater volume while therefore with the dilution biochemical process, processing this type of waste water, this has not only wasted a large amount of Freshwater resources, but also increased considerably the quantity discharged of waste water, do not meet national disposal of pollutants policy.

Domestic also have Some Enterprises first by the method for multiple-effect evaporation desalination, high-salt wastewater to be carried out to pre-treatment, and then process the water of condensation of multiple-effect evaporation by biochemical process.By the method for multiple-effect evaporation desalination, high-salt wastewater is carried out to pre-treatment, maximum obstacle is that the salt of crystallization does not have suitable outlet, reason is often to contain a large amount of organic pollutants in the salt of crystallization, can not use as general Industrial Salt, and in most of the cases this salt can only be considered as hazardous solid waste, must entrust and have the unit of qualification to carry out harmlessness disposing, 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 technique of sodium chloride aqueous solution (being commonly called as salt solution or bittern) electrolysis mainly contains two classes, and a class 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 the water quality requirement that advances groove salt solution, the TOC index that the electrolyzer of take advances groove salt solution is example, and ion-exchange membrane electrolyzer requires must be less than 10mg/L into groove salt solution TOC, and diaphragm sell requires to be less than 200mg/L into the TOC of groove salt solution.If can drop to 200mg/L to the TOC of high-salt wastewater by appropriate means or, below 10mg/L, just can produce high-salt wastewater as chlor-alkali plant the raw material use of chlorine and caustic soda.

In addition, in developed country, also have minority enterprise to adopt the methods such as wet oxidation, Catalytic Wet Oxidation and burning to process high-salt wastewater, 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 high-salt wastewater by catalytic wet peroxide oxidation method, make its TOC concentration advance the high-salt wastewater recycling processing method of groove salt solution TOC limit value lower than the chlor-alkali plant electrolyzer.

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

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

(2) take appropriate oxygenant and catalyzer, described oxygenant is hydrogen peroxide (hydrogen peroxide), and dosage is 0.2-0.4mol-H ₂o ₂/ g-TOC, the i.e. corresponding 0.2-0.4molH that adds of every gram TOC ₂o ₂; Described catalyzer is iron protochloride or ferrous sulfate, and dosage is 12-36mmol/L;

(3) slowly drip oxygenant and catalyzer, the mode that oxygenant adopts in batches slowly dropping or continuously slow stream to add adds, and in 1-6 hours, adds complete; The mode that catalyzer also adopts in batches slowly dropping or continuously slow stream to add adds, and in 1-6 hour, adds complete; From dripping for the first time oxygenant, measure the pH value of primary first-order equation liquid every 5-30min, and the pH value of controlling reaction solution is at 2.5-3.5, or, by the adding of pH automatic controlling system hydrochloric acid or sodium hydroxide, make the pH value stabilization of reaction solution at 2.5-3.5;

(4) after treating that oxygenant and catalyzer all add, continue reaction 15-180min, yet with sodium hydroxide, the pH value of reaction solution is adjusted to neutrality or slight alkalinity, precipitates or remove by filter catalyzer, the supernatant liquor of precipitation or filtrate 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 key point, by following formula, is undertaken:

1) oxygenant dosing method:

The volume of supposing high-salt wastewater is V _w(L), before oxide treatment, the TOC concentration of high-salt wastewater is TOC ₀(g/L) oxygenant (hydrogen peroxide) amount that need to add while, with catalytic wet peroxide oxidation, processing this waste water is:

M _HP＝(0.2~0.4)×（TOC ₀×V _W） （1）

In formula: M _hP-hydrogen peroxide the total amount (mol) that need to add,

Hydrogen peroxide 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-oxide treatment,

V _wthe volume of-water (L);

For ease of application, by M _hPconvert volume to, calculating formula is as follows:

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

In formula: V _hPthe cumulative volume (L) of-hydrogen peroxide that need to add,

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

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

C _hPthe mass percentage concentration of-hydrogen peroxide (%);

The time that the adds 1-6 hour that hydrogen peroxide is total, the dioxygen water yield that average per minute 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 formula: v _hP-hydrogen peroxide volume (mL/min) that average per minute adds.

If the ★ hydrogen peroxide is continuous dropping (or stream adds), by the speed shown in formula (3), drip continuously (or stream adds);

If ★ intermittently drips, every (1-15) min, drip once, average each amount dripped is:

q _HP＝(1.7-309.0)TOC ₀·V _W/C _HP (4)

Q in formula _hP-average each hydrogen peroxide volume (mL/ time) dripped.

2) catalyzer dosing method:

The volume of supposing waste water is V _w(L) catalytic amount that, needs to add is:

M _CFe＝(12~36)×V _w (5a)

M _CCu＝(0~3)×V _w (5b)

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

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

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

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

V _wthe volume of-waste water (L);

The time that always adds of catalyzer is 1 ~ 6 hour, and the catalytic amount that average per minute adds is:

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

In formula: m _c-catalytic amount (mmol/min) that average per minute adds.

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

The time that always adds of catalyzer is 1-6 hour, and the catalytic amount that average per minute adds is:

If the ★ aqueous catalyst solution is continuous dropping (or stream adds), by the speed shown in formula (6), drip continuously (or stream adds);

If ★ intermittently drips, every (1 ~ 15) min, drip once, average each amount dripped is:

q _C＝(1~15)m _C＝(0.033~9.00)V _W (7)

In formula: q _c---average each catalytic amount (mmol/ time) dripped.

Be that the continuous slowly stream of step (3) oxidizer refers to, the oxygenant volume that average per minute adds is (1.7 ~ 20.6) TOC ₀v _w/ C _hPmilliliter (is annotated: TOC ₀the TOC concentration of high-salt wastewater before-oxide treatment, g/L; V _wthe volume of-high-salt wastewater, L; C _hPthe mass percentage concentration of-hydrogen peroxide, %, lower same.), continuously slow stream adds catalyzer and refers to, and the catalytic amount that average per minute adds is (0.033 ~ 0.60) V _wmmole; Slowly drip oxygenant in batches and refer to, drip once every 1-15min, average each amount dripped is (1.7 ~ 309.0) TOC ₀v _w/ C _hPmilliliter; Slowly drip catalyzer in batches and refer to, the catalytic amount on average at every turn added is (0.033 ~ 9.00) V _wmmole.

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

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

The invention has the advantages that, the invention discloses a kind of haline water resource treatment technique, remove contained organic pollutant in high-salt wastewater by catalytic wet peroxide oxidation method, the dosage of optimization of catalysts and oxygenant and dosing method, especially by catalyzer and oxygenant, slowly drip in batches or continuously, make the waste water TOC concentration of processing advance the TOC limit value of groove salt solution lower than the chlor-alkali plant electrolyzer, the raw material that so just the high-salt wastewater of processing can be produced to chlorine and caustic soda as chlor-alkali plant is used, realize the zero release of recycling and the waste water of high-salt wastewater, Sustainable development tool to protection water surrounding and promotion relevant industries is of great significance.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.The experimental technique used in following embodiment if no special instructions, is ordinary method.In following embodiment, material used, reagent etc., if no special instructions, all can obtain from commercial channels.Should be understood that these embodiment only are not used in and limit the scope of the invention for the present invention is described.

Embodiment 1

Step 1: use hydrochloric acid epoxy chloropropane waste water (TOC=1620mg/L, NaCl=21.5%) pH value is transferred to 3.0, then the water sample of 800mL being regulated to pH adds in tri-mouthfuls of round-bottomed flasks of 1000mL, again there-necked flask is placed in to the water bath with thermostatic control of 90 ℃, one of the centre of there-necked flask mouth is equipped with stirring rod, slotting pH electrode of another two mouths, also have one as dosing mouth.Open mechanical stirring, the preheating water sample.

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

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

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

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

Embodiment 2

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

Step 2-step 4: with embodiment 1.

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

Embodiment 3

Step 1: with embodiment 2.

Step 2: take 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, then both mixtures are dissolved in 10mL water, as catalyzer; Get the hydrogen peroxide (about 0.44mol) of 45mL 30% with graduated cylinder, as oxygenant.

Step poly-three and step 4 are with embodiment 1.

The TOC measurement result is 90mg/L, meets the requirement that diaphragm sell advances groove salt solution TOC<200mg/L.

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

Embodiment 4

Step 1: with embodiment 1.

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

Step poly-three and step 4 are with embodiment 1.

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

Embodiment 5

Step 1: with embodiment 1.

Step 2: with embodiment 1.

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

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 liquor.

The TOC measurement result is 895mg/L, does not meet the requirement that diaphragm sell advances groove salt solution TOC<200mg/L.

Embodiment 6

Step 1: with embodiment 1.

Step 2: with embodiment 1.

Step poly-three: when the temperature of water sample and bath temperature are basic identical in there-necked flask, disposable the adding reaction flask of catalyzer prepared from the dosing mouth handle, slowly drip the 1mL oxygenant simultaneously, then every 3min, drip the 1mL oxygenant, until oxygenant all drips off.From dripping for the first time oxygenant, measure the pH value of primary first-order equation liquid every 10min, and with hydrochloric acid or sodium hydroxide, the pH value of reaction solution is controlled to 2.5-3.5.

Step 4: with embodiment 1.

The TOC measurement result is 286mg/L, does not meet the requirement that diaphragm sell advances groove salt solution TOC<200mg/L.

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

Embodiment 7

Step 1: use hydrochloric acid the pretreated vinylidene chloride waste water of process stripping (TOC=285mg/L, NaCl=20.3%) pH value is transferred to 3.5, then the water sample of 800mL being regulated to pH adds in tri-mouthfuls of round-bottomed flasks of 1000mL, again there-necked flask is placed in to the water bath with thermostatic control of 90 ℃, one of the centre of there-necked flask mouth is equipped with stirring rod, slotting pH electrode of another two mouths, also have one as dosing mouth.Open mechanical stirring, the preheating water sample.

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

Step 3: when the temperature of water sample and bath temperature are basic identical in there-necked flask, drip the 1mL catalyzer from dosing mouth, slowly drip the 1mL oxygenant simultaneously, then every catalyzer of 15min dropping and oxygenant, both dripping quantity are 1mL, until catalyzer and oxygenant all drip off.From dripping for the first time oxygenant, measure the pH value of primary first-order equation liquid every 10min, and with hydrochloric acid or sodium hydroxide, the pH value of reaction solution is controlled to 2.5-3.5.

Step 4: with embodiment 1.

The TOC measurement result is 22mg/L, meets the requirement that diaphragm sell advances groove salt solution TOC<200mg/L.

Step 5: with hydrochloric acid, the pH value of 500mL supernatant liquor is transferred to 2.0, then adds the 0.1g Powdered Activated Carbon, after stirring 120min, filter, record the TOC=4mg/L of filtrate, meet the requirement that groove salt solution TOC<10mg/L is advanced in electrolysis with ion-exchange film.

Embodiment 8

Step 1: use hydrochloric acid the pretreated hydrazine hydrate waste water of process stripping (TOC=316mg/L, NaCl=6.3%) pH value is transferred to 3.5, then the water sample of 800mL being regulated to pH adds in tri-mouthfuls of round-bottomed flasks of 1000mL, again there-necked flask is placed in to the water bath with thermostatic control of 90 ℃, one of the centre of there-necked flask mouth is equipped with stirring rod, slotting pH electrode of another two mouths, also have one as dosing mouth.Open mechanical stirring, the preheating water sample.

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

Step 3: with embodiment 7.

Step 4: with embodiment 1.

The TOC measurement result is 58mg/L, meets the requirement that diaphragm sell advances groove salt solution TOC<200mg/L.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (2)

1. a high-salt wastewater recycling processing method, remove high salt by catalytic wet peroxide oxidation method useless

Contained organic pollutant in water, is characterized in that, comprises the steps:

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

(2) take appropriate oxygenant and catalyzer, described oxygenant is hydrogen peroxide, and dosage is 0.2-0.4 mol-H ₂o ₂/ g-TOC; Described catalyzer is iron protochloride or ferrous sulfate, and dosage is 12-36 mmol/L;

(3) slowly drip oxygenant and catalyzer, the mode that oxygenant adopts in batches slowly dropping or continuously slow stream to add adds, and in 1-6 hours, adds complete; The mode that catalyzer also adopts in batches slowly dropping or continuously slow stream to add adds, and in 1-6 hours, adds complete; From dripping for the first time oxygenant, measure the pH value of primary first-order equation liquid every 5-30min, control the pH value of reaction solution at 2.5-3.5;

(4) after treating that oxygenant and catalyzer all add, continue reaction 15-180min, then with sodium hydroxide, the pH value of reaction solution is adjusted to neutrality or slight alkalinity, precipitates or remove by filter catalyzer, the supernatant liquor of precipitation or filtrate can be used as the raw material use that electrolytic process is produced chlorine and caustic soda;

Step (3) slowly flows continuously oxidizer and refers to, the hydrogen peroxide volume that average per minute adds is 1.7 ~ 20.6TOC ₀v _w/ C _hPmilliliter, described TOC ₀the TOC concentration of high-salt wastewater before-oxide treatment, g/L; V _wthe volume of-high-salt wastewater, L; C _hPthe mass percentage concentration of-hydrogen peroxide, %; Continuously slow stream adds catalyzer and refers to, the catalytic amount that average per minute adds is 0.033 ~ 0.60V _wmmole;

Step (3) slowly drips oxygenant in batches and refers to, every 1-15min, drips once, and average each amount dripped is 1.7 ~ 309.0TOC ₀v _w/ C _hPmilliliter; Slowly drip catalyzer in batches and refer to, average each catalytic amount dripped is 0.033 ~ 9.00V _wmmole.

2. a kind of high-salt wastewater recycling processing method according to claim 1, is characterized in that step

(2) described catalyzer also has cupric chloride or copper sulfate, and dosage is not for higher than 3 mmol/L.