Treatment method and treatment system for valeraldehyde condensation waste lye

Abstract

The invention provides a treatment method and a treatment system for valeraldehyde condensation waste lye. The treatment method comprises the following steps: step 1, acidizing the valeraldehyde condensation waste lye, and layering to obtain an organic phase and a water phase; step 2, concentrating the water phase to obtain concentrated water; 3, conveying the concentrated water to a five-chamber bipolar membrane electrodialysis device to obtain an organic acid solution and a NaOH solution; wherein the five-chamber bipolar membrane electrodialysis device is sequentially provided with an anode electrolysis chamber, a dilute acid isolation chamber, an acid chamber, a central isolation chamber, an alkali chamber, a dilute alkali isolation chamber and a cathode electrolysis chamber, the concentrated water is conveyed to the central isolation chamber, under the action of a direct-current electric field, Na < + > separated from the concentrated water enters the alkali chamber and is combined with OH <-> to generate NaOH, and the NaOH is separated from the acid chamber. Carboxylate radical ions ionized from the concentrated water enter the acid chamber to be combined with H < + > to generate organic acid, dilute organic acid in the dilute acid isolation chamber serves as circulating liquid of the acid chamber, and a dilute NaOH solution in the dilute alkali isolation chamber serves as circulating liquid of the alkali chamber.

Description

Technical Field

[0001] The invention belongs to the field of chemical waste alkali liquor treatment, and specifically relates to a treatment method and a treatment system for valeraldehyde condensation waste alkali liquor. Background Art

[0002] Valeraldehyde condensation is an intermediate unit in the industrial production of 2-propylheptanol (2-PH). Two moles of n-valeraldehyde produce one mole of decenal and one mole of water under the condition of catalyst NaOH. In addition, Cannizzaro reaction will also occur under this condition. The reaction formula is:

[0003] 2CH3CH2CH2CH2CHO+NaOH→

[0004] CH3CH2CH2CH2COONa+CH3CH2CH2CH2CH2OH

[0005] Since water is generated during the condensation process and Cannizzaro Reaction also consumes NaOH, the alkali concentration of the device will gradually decrease. In order to maintain a constant alkali concentration, part of the alkali solution will be discharged and part of the fresh alkali solution will be added. The discharged part of the alkali solution is called waste alkali solution. The alkali content of the waste alkali solution is 1-2%, and the organic composition is complex, mainly including valeraldehyde, amyl alcohol, valeric acid, decenal, etc. The chemical oxygen demand (COD Cr ) is around 60000~110000mg / L.

[0006] At present, the waste alkali liquid from the domestic valeraldehyde condensation device is diluted and sent to the sewage treatment plant, which further increases the load on the sewage treatment system.

[0007] Chinese patent CN108128982A discloses a method for treating waste alkali liquor from condensation of valeraldehyde, comprising the following steps: (1) wastewater enters a concentration bag device, the concentrated liquid obtained by the concentration bag device is cooled by a cooler and then enters an acidification tank, and the water concentrated by the concentration bag device enters a biochemical treatment plant for biochemical treatment; (2) the concentrated liquid at the outlet of the acidification tank enters a chromatograph to obtain an organic phase and an aqueous phase; (3) the organic phase enters a distillation tower, valeric acid is obtained at the top of the distillation tower, the heavy components in the bottom of the distillation tower enter an incinerator, and the aqueous phase enters an evaporation crystallizer to obtain water and solid salt. This invention solves the problem of heavy load on sewage treatment plants during wastewater treatment, and also recovers organic acids. However, this method first evaporates and concentrates the waste alkali liquor, and the evaporated water will take away some organic matter, and there is still a low COD Cr The wastewater needs to be treated in a sewage plant, and the solid salt obtained is of low purity and has little utilization value.

[0008] Chinese patent CN104071940B discloses a method for treating waste alkali liquor of 1,2-butanol, which first uses an inorganic acid to acidify the waste alkali liquor, then performs a permeation vaporization membrane evaporation concentration treatment on the acidified liquor, or performs a permeation vaporization membrane evaporation after deoiling the acidified liquor, cools and crystallizes the evaporated concentrated liquor after oil-water separation to recover the inorganic acid sodium salt, returns the crystallization kettle liquid to the acidification reactor for cyclic treatment, and performs adsorption treatment on the evaporated condensate. Part of the adsorbed water is returned to the condensation device for preparing alkali liquor, and part is discharged into the sewage treatment plant. This method realizes the resource recovery of organic matter, and at the same time, it can also recover the inorganic salts produced in the acidification process as by-products. The treated water can also replace fresh desalted water to prepare alkali liquor, but the inorganic salts obtained by this method are of low purity and low value, and still have low COD Cr Wastewater generation.

[0009] There is still a need to study the treatment of valeraldehyde condensation waste alkali liquor in this field. Summary of the invention

[0010] The main purpose of the present invention is to provide a method and system for treating valeraldehyde condensation waste alkali liquor, so as to overcome the problem that the product obtained after treating valeraldehyde condensation waste alkali liquor in the prior art has little value and still produces low COD wastewater.

[0011] In order to achieve the above object, the present invention provides a method for treating valeraldehyde condensation waste alkali liquor, comprising the following steps:

[0012] Step 1, acidifying the valeraldehyde condensation waste alkali solution, and separating the layers to obtain an organic phase and an aqueous phase;

[0013] Step 2, concentrating the aqueous phase to obtain concentrated water;

[0014] Step 3, transporting the concentrated water to a five-chamber bipolar membrane electrodialysis device to obtain an organic acid solution and a NaOH solution;

[0015] The five-chamber bipolar membrane electrodialysis device is provided with an anode electrolysis chamber, a dilute acid isolation chamber, an acid chamber, a central isolation chamber, an alkali chamber, a dilute alkali isolation chamber, and a cathode electrolysis chamber in sequence. The concentrated water is transported to the central isolation chamber. Under the action of the DC electric field, the Na + Entering the alkaline chamber and OH - Combined with NaOH, the carboxylate ions ionized from the concentrated water enter the acid chamber and react with H + The organic acid is generated by combining, and the dilute organic acid in the dilute acid isolation chamber is used as the circulating liquid of the acid chamber, and the dilute NaOH solution in the dilute alkali isolation chamber is used as the circulating liquid of the alkali chamber.

[0016] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps: the anode electrolysis chamber and the dilute acid isolation chamber are separated by a cation exchange membrane, and the cathode electrolysis chamber and the dilute alkali isolation chamber are separated by an anion exchange membrane.

[0017] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps: the dilute acid isolation chamber and the acid chamber, the dilute alkali isolation chamber and the alkali chamber are separated by a bipolar membrane, the acid chamber and the central isolation chamber are separated by an anion exchange membrane, and the alkali chamber and the central isolation chamber are separated by a cation exchange membrane.

[0018] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps: the acid used for the acidification treatment is valeric acid; during the acidification treatment, the pH value of the valeraldehyde condensation waste alkali liquor is adjusted to 0-6 and the temperature is adjusted to 25-60°C.

[0019] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps: the stratification is performed by centrifugation, the centrifugal speed is 500 to 3000 rpm, and the centrifugal time is 1 to 10 min; the organic phase obtained by the stratification is used as a by-product, or the organic phase obtained by the stratification is transported to a distillation tower for separation, and the obtained organic acid is circulated for acidification treatment.

[0020] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps: the number of plates of the distillation tower is 30 to 60, the number of feed plates is 16 to 26, the reflux ratio is 1.9 to 2.9, the tower pressure is 5 to 50 kPa, the tower top temperature is 40 to 60°C, and the tower bottom temperature is 120 to 130°C.

[0021] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps: when the aqueous phase is concentrated, the distilled water obtained is circulated to prepare the alkali liquor used in the valeraldehyde condensation process.

[0022] In the method for treating the valeraldehyde condensation waste alkali liquor of the present invention, the concentration of the sodium carboxylate in the concentrated water is 2-3 mol / L.

[0023] In order to achieve the above object, the present invention also provides a treatment system for valeraldehyde condensation waste alkali liquor, comprising:

[0024] Acidification device, used for acidification treatment of valeraldehyde condensation waste alkali liquor;

[0025] A separation device is connected to the acidification device to separate the acidified valeraldehyde condensation waste alkali solution into layers to obtain an organic phase and an aqueous phase;

[0026] a concentrating device, connected to the separating device, to concentrate the aqueous phase to obtain concentrated water;

[0027] A five-chamber bipolar membrane electrodialysis device is connected to the concentrating device. The five-chamber bipolar membrane electrodialysis device is sequentially provided with an anode electrolysis chamber, a dilute acid isolation chamber, an acid chamber, a central isolation chamber, an alkali, a dilute alkali isolation chamber, and a cathode electrolysis chamber. The concentrated water is transported to the central isolation chamber. Under the action of a DC electric field, the Na ionized from the concentrated water is + Entering the alkaline chamber and OH - Combined with NaOH, the carboxylate ions ionized from the concentrated water enter the acid chamber and react with H + The organic acid is generated by combining, and the dilute organic acid in the dilute acid isolation chamber is used as the circulating liquid of the acid chamber, and the dilute NaOH solution in the dilute alkali isolation chamber is used as the circulating liquid of the alkali chamber.

[0028] The treatment system of the valeraldehyde condensation waste alkali liquor of the present invention is characterized in that the anode electrolysis chamber and the dilute acid isolation chamber are separated by a cation exchange membrane, the cathode electrolysis chamber and the dilute alkali isolation chamber are separated by an anion exchange membrane, the dilute acid isolation chamber and the acid chamber, and the dilute alkali isolation chamber and the alkali chamber are separated by bipolar membranes, the acid chamber and the central isolation chamber are separated by an anion exchange membrane, and the alkali chamber and the central isolation chamber are separated by a cation exchange membrane.

[0029] Beneficial effects of the present invention:

[0030] The present invention provides a five-chamber bipolar membrane electrodialysis device with a dilute alkali isolation chamber and a dilute acid isolation chamber, and uses the generated dilute alkali and dilute acid as circulating liquids in the alkali chamber and the acid chamber, respectively, thereby further improving the recovery rate and purity of the alkali and acid recovered in the alkali chamber and the acid chamber, and improving the value of the obtained product.

[0031] Furthermore, the present invention can protect the electrode materials of the anode electrolysis chamber and the cathode electrolysis chamber by setting a dilute alkali isolation chamber and a dilute acid isolation chamber to prevent organic acid radical ions from contacting the anode material, Na + Contact the cathode material, thereby preventing the electrode material from being damaged. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of a five-chamber bipolar membrane electrodialysis device according to one embodiment of the present invention.

[0033] Figure 2 The present invention is a schematic diagram of a system for treating waste alkali liquor from condensation of valeraldehyde according to an embodiment of the present invention.

[0034] Wherein, the reference numerals are:

[0035] 1 Anode electrolysis chamber

[0036] 2 Dilute acid isolation room

[0037] 3 Acid Chamber

[0038] 4 Central Isolation Room

[0039] 5 Alkali Room

[0040] 6 Dilute Alkali Isolation Room

[0041] 7 Cathode electrolysis chamber

[0042] 11 Acidification device

[0043] 12 Separation device

[0044] 13. Distillation tower

[0045] 14 Concentration device

[0046] 15 Condenser

[0047] 16 Five-chamber bipolar membrane electrodialysis device

[0048] 17NaOH solution

[0049] 18 Organic acid solution

[0050] 19 Waste alkali liquor from condensation of valeraldehyde

[0051] 20 Valeric acid

[0052] 21 Organic phase

[0053] 22 Valeric acid

[0054] 23 Heavy components

[0055] 24 Evaporation of water

[0056] 25 Water phase

[0057] A Cation exchange membrane

[0058] B Bipolar membrane

[0059] C Anion Exchange Membrane

[0060] D Cation exchange membrane

[0061] E Bipolar membrane

[0062] F Anion Exchange Membrane DETAILED DESCRIPTION

[0063] The technical scheme of the present invention is described in detail below. The following implementation modes are implemented on the premise of the technical scheme of the present invention, and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following implementation modes. The structures or experimental methods of specific conditions are not specified in the following implementation modes, and generally conventional conditions are followed.

[0064] The invention provides a method for treating valeraldehyde condensation waste alkali liquor, which generally contains 1-2wt% of NaOH and organic substances such as n-valeraldehyde, n-pentanol, sodium valerate, decenal, n-valeric acid, etc.

[0065] The method for treating the valeraldehyde condensation waste alkali liquor of the present invention comprises the following steps:

[0066] Step 1, acidifying the valeraldehyde condensation waste alkali solution, and separating the layers to obtain an organic phase and an aqueous phase;

[0067] Step 2, concentrating the aqueous phase to obtain concentrated water;

[0068] Step 3, transporting the concentrated water to a five-chamber bipolar membrane electrodialysis device to obtain an organic acid solution and a NaOH solution;

[0069] The five-chamber bipolar membrane electrodialysis device is provided with an anode electrolysis chamber, a dilute acid isolation chamber, an acid chamber, a central isolation chamber, an alkali chamber, a dilute alkali isolation chamber, and a cathode electrolysis chamber in sequence. The concentrated water is transported to the central isolation chamber. Under the action of the DC electric field, the Na + Entering the alkaline chamber and OH - Combined with NaOH, the carboxylate ions ionized from the concentrated water enter the acid chamber and react with H + The organic acid is generated by combining, and the dilute organic acid in the dilute acid isolation chamber is used as the circulating liquid of the acid chamber, and the dilute NaOH solution in the dilute alkali isolation chamber is used as the circulating liquid of the alkali chamber.

[0070] The present invention provides a five-chamber bipolar membrane electrodialysis device with a dilute alkali isolation chamber and a dilute acid isolation chamber, and uses the generated dilute alkali and dilute acid as circulating liquids in the alkali chamber and the acid chamber, respectively, thereby further improving the purity of the alkali and acid recovered in the alkali chamber and the acid chamber, and improving the value of the obtained product.

[0071] In step 1 of the present invention, the valeraldehyde condensation waste alkali liquid is firstly subjected to an acidification treatment, that is, the valeraldehyde condensation waste alkali liquid is mixed with an acid. In one embodiment, the acid used in the present invention is an organic acid, further, a carboxylic acid having the same carbon number as the raw material aldehyde, and further, a straight-chain carboxylic acid, such as valeric acid. The present invention uses an organic acid to acidify the waste alkali liquid. The weak acid can reduce the corrosion to the equipment, and at the same time recover the organic matter in the waste alkali liquid as a by-product or separate the organic acid in the organic matter for recycling. The amount of acid used is to adjust the pH value of the valeraldehyde condensation waste alkali liquid to 0-6, preferably 2.5-3.5, for example 3, and the acidification temperature is set to 25-60°C, and the optimal acidification temperature is 35-45°C, for example 40°C. Carboxylate is generated in the acidified valeraldehyde condensation waste alkali liquid. Due to the salting-out effect, the organic matter is precipitated from the water, and the oil and water are separated. The separation method is, for example, centrifugation to obtain an organic phase and an aqueous phase. In another embodiment, the centrifugation time is 1 to 10 min, preferably 1 to 5 min, such as 4 min, and the rotation speed is 500 to 3000 rpm, preferably 1000 to 2000 rpm, such as 1500 rpm.

[0072] The organic phase can be used as a by-product or can be transported to a distillation tower for separation, and the separated organic acid is recycled for the above-mentioned acidification treatment. In one embodiment, the number of plates of the distillation tower is 30 to 60, the feed plates are 16 to 26, the reflux ratio is 1.9 to 2.9, the tower pressure is 5 to 50 kPa, the tower top temperature is 40 to 60 ° C, and the tower bottom temperature is 120 to 130 ° C; for example, the number of plates is 30, the feed plates are 16, the reflux ratio is 1.9, the tower pressure is 5 kPa, the tower top temperature is 40 ° C, and the tower bottom temperature is 120 ° C.

[0073] The aqueous phase after stratification contains almost no alcohol, aldehyde and heavy components in the valeraldehyde condensation waste alkali solution, and the main component is carboxylate. The aqueous phase is concentrated, and the concentration temperature is, for example, 100-120°C, more preferably 106°C. The concentration increases the concentration of carboxylate to obtain concentrated water, and the evaporated water can be recycled for preparing the alkali solution used in the valeraldehyde condensation process. In one embodiment, the concentration of sodium carboxylate in the concentrated water is 2-3 mol / L.

[0074] Then, the concentrated water is transported to a five-chamber bipolar membrane electrodialysis device to obtain an organic acid solution and a NaOH solution.

[0075] The five-chamber bipolar membrane electrodialysis device of the present invention is as follows Figure 1As shown, an anode electrolysis chamber 1, a dilute acid isolation chamber 2, an acid chamber 3, a central isolation chamber 4, an alkali chamber 5, a dilute alkali isolation chamber 6 and a cathode electrolysis chamber 7 are sequentially arranged. The anode electrolysis chamber 1 is adjacent to the dilute acid isolation chamber 2, and the two are separated by a cation exchange membrane A; the dilute acid isolation chamber 2 is adjacent to the acid chamber 3, and the two are separated by a bipolar membrane B; the acid chamber 3 is adjacent to the central isolation chamber 4, and the two are separated by an anion exchange membrane C; the central isolation chamber 4 is adjacent to the alkali chamber 5, and the two are separated by a cation exchange membrane D; the alkali chamber 5 is adjacent to the dilute alkali isolation chamber 6, and the two are separated by a bipolar membrane E; the dilute alkali isolation chamber 6 is adjacent to the cathode electrolysis chamber 7, and the two are separated by an anion exchange membrane F.

[0076] The present invention can protect the electrode materials of the anode electrolysis chamber and the cathode electrolysis chamber by setting the dilute alkali isolation chamber and the dilute acid isolation chamber to prevent organic acid from contacting the anode material, Na + Contact the cathode material, thereby preventing the electrode material from being damaged.

[0077] In detail, sodium sulfate is used as electrolyte in the anode electrolysis chamber 1 and the cathode electrolysis chamber 7, respectively. The sodium sulfate electrolyte can be recycled. Sodium sulfate is used as auxiliary chamber in the dilute acid isolation chamber 2 and the dilute alkali isolation chamber 6. Concentrated water enters the central isolation chamber 4. Under the action of the electric field, organic acid radicals such as valerate pass through the anion exchange membrane C and enter the acid chamber 3. + Through the cation exchange membrane D, it enters the alkaline chamber 5; under the action of the electric field, the water in the bipolar membrane B and E dissociates to generate H + and OH - , organic acid radicals and H + In the acid chamber 3, organic acid is generated, Na + and OH - NaOH is generated in the alkali chamber 5. The dilute sodium valerate solution flowing out of the central isolation chamber 4 is recycled after being supplemented with valeric acid to increase its solution concentration.

[0078] In order to prevent a small amount of organic acid radical ions in the acid chamber 3 from entering the anode electrolysis chamber 1 through the bipolar membrane B using the concentration difference, the present invention is specially provided with a dilute acid isolation chamber 2 and a cation exchange membrane A, so as to prevent the organic acid radical ions from adhering to the anode plate and losing electrons to generate acidic gases such as CO2, thereby avoiding damage to the anode plate. Similarly, in order to prevent a small amount of Na + By utilizing the concentration difference, Na+ enters the cathode electrolysis chamber 7 through the bipolar membrane E. A dilute alkali isolation chamber 6 and an anion exchange membrane F are specially provided to avoid Na+ + It adheres to the cathode plate, then obtains electrons to generate metallic sodium which adheres to the surface of the cathode plate, thus avoiding damage to the cathode plate.

[0079] The small amount of organic acid radical ions in the acid chamber 3 of the present invention will enter the dilute acid isolation chamber 2 through the bipolar membrane B by utilizing the concentration difference, and the H obtained by electrolysis of water in the anode electrolysis chamber 1+ It will enter the dilute acid isolation chamber 2 through the cation exchange membrane A. According to the principle of electrical neutrality, a dilute organic acid such as dilute valeric acid will flow out of the dilute acid isolation chamber 2. The dilute organic acid can be used as the circulating liquid of the acid chamber 3 to improve the concentration and purity of the organic acid such as valeric acid flowing out of the acid chamber 3. + The ions will enter the dilute alkali isolation chamber 6 through the bipolar membrane E by using the concentration difference, and the OH obtained by electrolysis of water in the cathode electrolysis chamber 7 - It will enter the dilute alkali isolation chamber 6 through the anion exchange membrane F. According to the principle of electrical neutrality, a dilute NaOH solution will flow out of the dilute alkali isolation chamber 6. The dilute NaOH solution can be used as the circulating liquid of the alkali chamber 5 to improve the concentration and purity of the NaOH flowing out of the alkali chamber 5.

[0080] In one embodiment, the membrane stack size of the five-chamber bipolar membrane electrodialysis device of the present invention is 90*210mm 2 The membrane performance parameters are shown in Table 1 below, but the present invention is not limited thereto and can be selected as needed.

[0081] Table 1

[0082]

[0083] Therefore, the present invention provides a method for treating waste alkali liquor from valeraldehyde condensation. First, the waste alkali liquor from valeraldehyde condensation enters an acidification system, and the upper organic phase is recovered as a by-product or sent to a distillation tower to separate organic acid as acid for acidification; then the lower aqueous phase enters a concentration system for evaporation and concentration, and the evaporated water vapor condenses into liquid for the preparation of alkali liquor; the concentrated aqueous phase enters an improved five-chamber bipolar membrane electrodialysis system, and a high-concentration NaOH is obtained in the alkali chamber, and a high-concentration organic acid is obtained in the acid chamber.

[0084] The present invention also provides a system for treating waste alkali liquor from condensation of valeraldehyde, such as Figure 2 As shown, including:

[0085] Acidification device 11, used for acidification treatment of valeraldehyde condensation waste alkali solution 19;

[0086] The separation device 12 is connected to the acidification device 11 to separate the acidified valeraldehyde condensation waste alkali solution into layers to obtain an organic phase 21 and an aqueous phase 25;

[0087] a concentrating device 14, connected to the separating device 12, to concentrate the aqueous phase 25 to obtain concentrated water and evaporated water 24;

[0088] The five-chamber bipolar membrane electrodialysis device 16 is connected to the concentration device 14 to process the concentrated water to obtain an organic acid solution 18 and a NaOH solution 17 .

[0089] The present invention does not specifically limit the structures of the acidification device 11, the separation device 12, and the concentration device 14. Conventional devices in the art can be used as long as they can achieve the corresponding functions described above. The structure of the five-chamber bipolar membrane electrodialysis device 16 has been described in detail above and will not be repeated here.

[0090] In one embodiment, the acid used for the acidification treatment is n-valeric acid 20, and the n-valeric acid 20 and the valeraldehyde condensation waste alkali liquid 19 are transported together to the acidification device 11 for acidification treatment under stirring.

[0091] In one embodiment, the organic phase 21 can be directly discharged from the system as a by-product, or can be transported to the distillation tower 13 for separation, and the separated organic acid 22 is recycled for the above-mentioned acidification treatment, and the obtained heavy component 23 is discharged from the system.

[0092] In one embodiment, the concentrated water may be condensed and cooled in the condenser 15 before being transported to the five-chamber bipolar membrane electrodialysis device 16 .

[0093] The technical solution of the present invention will be further described by specific examples. The valeraldehyde condensation waste alkali liquor comes from Daqing Chemical Research Center of China National Petroleum Corporation, where the alkali concentration is 1.6-1.86wt%, COD Cr It is 60000~110000mg / L.

[0094] Evaluation and analysis methods:

[0095] (1) The potassium dichromate method was used to determine COD.

[0096] (2) The amount of recovered acid and base was determined by acid-base titration.

[0097] Example 1

[0098] Take 2L of valeraldehyde condensation waste alkali solution (NaOH content is 1.8g / 100ml, sodium valerate 8.6g / 100ml, valeraldehyde 0.2g / 100ml, amyl alcohol 0.2g / 100ml, decenal 0.15g / 100ml), COD Cr The concentration is 11652 mg / L. The waste alkali solution is acidified with n-pentanoic acid, the pH is adjusted to 3, the acidification temperature is 45-60 degrees Celsius, the centrifugation time is 4 minutes, the speed is 1500 rpm, the oil and water are separated, 39 ml of the oil phase is recovered as a by-product, the lower water phase is 1.96 L, and the COD of the clarified water phase is measured to be 8250 mg / L. Then the water phase is evaporated and concentrated, the temperature is set to 106°C, and the concentration of the carboxylate is 2 mol / L. The concentrate is electrodialyzed using the five-chamber bipolar membrane electrodialysis device of the present invention, and the current density is 30 mA / cm 2, the concentrated sodium valerate is converted into NaOH and n-valeric acid, the dilute acid and dilute alkali flowing out of the dilute acid isolation chamber and the dilute alkali isolation chamber are returned to the acid chamber and the alkali chamber as circulating liquid, the recovered NaOH solution is 1.4L, the mass concentration is 5.96g / 100ml, the NaOH recovery rate is 91.2%, and the recovered n-valeric acid solution is 0.8L, the concentration is 32.66g / 100ml, and the n-valeric acid recovery rate is 92.1%.

[0099] Example 2

[0100] Take 2L of valeraldehyde condensation waste alkali solution (NaOH content is 1.8g / 100ml, sodium valerate 8.6g / 100ml, valeraldehyde 0.2g / 100ml, amyl alcohol 0.2g / 100ml, decenal 0.15g / 100ml), COD Cr The concentration is 11652 mg / L. The waste alkali solution is acidified with n-pentanoic acid, the pH is adjusted to 3, the acidification temperature is 45-60 degrees Celsius, the centrifugation time is 4 minutes, the speed is 1500 rpm, the oil and water are separated, 39 ml of the oil phase is recovered as a by-product, the lower water phase is 1.96 L, and the COD of the clarified water phase is measured to be 8250 mg / L. Then the water phase is evaporated and concentrated, the temperature is set to 106°C, and the concentration of the carboxylate is 2.2 mol / L. The concentrate is electrodialyzed using the five-chamber bipolar membrane electrodialysis device of the present invention, and the current density is 30 mA / cm 2 , the concentrated sodium valerate is converted into NaOH and n-valeric acid, the dilute acid and dilute alkali flowing out of the dilute acid isolation chamber and the dilute alkali isolation chamber are returned to the acid chamber and the alkali chamber as circulating liquid, the recovered NaOH solution is 1.38L, the mass concentration is 6.06g / 100ml, the NaOH recovery rate is 91.4%, the recovered n-valeric acid solution is 0.78L, the mass concentration is 33.6g / 100ml, and the n-valeric acid recovery rate is 92.4%.

[0101] Example 3

[0102] Take 2L of valeraldehyde condensation waste alkali solution (NaOH content is 1.8g / 100ml, sodium valerate 8.6g / 100ml, valeraldehyde 0.2g / 100ml, amyl alcohol 0.2g / 100ml, decenal 0.15g / 100ml), COD CrThe concentration is 11652 mg / L. The waste alkali solution is acidified with n-pentanoic acid, the pH is adjusted to 3, the acidification temperature is 45-60 degrees Celsius, the centrifugation time is 4 minutes, the speed is 1500 rpm, the oil and water are separated, 39 ml of the oil phase is recovered as a by-product, the lower water phase is 1.96 L, and the COD of the clarified water phase is determined to be 8250 mg / L. Then the water phase is evaporated and concentrated, the temperature is set at 106°C, and the concentration of the carboxylate is 2.5 mol / L. The concentrate is electrodialyzed using the five-chamber bipolar membrane electrodialysis device of the present invention, and the current density is 30 mA / cm 2 The concentrated sodium valerate is converted into NaOH and n-valeric acid. The dilute acid and dilute alkali flowing out of the dilute acid isolation chamber and the dilute alkali isolation chamber are returned to the acid chamber and the alkali chamber as circulating liquid. The recovered NaOH solution is 1.38L, with a mass concentration of 6.06g / 100ml and a NaOH recovery rate of 91.5%. The recovered n-valeric acid solution is 0.82L, with a mass concentration of 32.17g / 100ml and a n-valeric acid recovery rate of 92.8%.

[0103] Example 4

[0104] Take 2L of valeraldehyde condensation waste alkali solution (NaOH content is 1.8g / 100ml, sodium valerate 8.6g / 100ml, valeraldehyde 0.2g / 100ml, amyl alcohol 0.2g / 100ml, decenal 0.15g / 100ml), COD Cr The concentration is 11652 mg / L. The waste alkali solution is acidified with n-valeric acid, the pH is adjusted to 3, the acidification temperature is 45-60 degrees Celsius, the centrifugation time is 4 minutes, the speed is 1500 rpm, the oil and water are separated, 39 ml of the oil phase is recovered as a by-product, the lower water phase is 1.96 L, and the COD of the clarified water phase is measured to be 8250 mg / L. Then the water phase is evaporated and concentrated, the temperature is set at 106°C, and the concentration of the carboxylate is 2.5 mol / L. The concentrate is electrodialyzed using the five-chamber bipolar membrane electrodialysis device of the present invention, and the current density is 40 mA / cm 2 , the concentrated sodium valerate is converted into NaOH and n-valeric acid, the dilute acid and dilute alkali flowing out of the dilute acid isolation chamber and the dilute alkali isolation chamber are returned to the acid chamber and the alkali chamber as circulating liquid, the recovered NaOH solution is 1.42L, the mass concentration is 5.89g / 100ml, the NaOH recovery rate is 91.5%, the recovered n-valeric acid solution is 0.84L, the mass concentration is 31.3g / 100ml, the n-valeric acid recovery rate is 92.6%.

[0105] Comparative Example 1

[0106] Take 2L of valeraldehyde condensation waste alkali solution (NaOH content is 1.8g / 100ml, sodium valerate 8.6g / 100ml, valeraldehyde 0.2g / 100ml, amyl alcohol 0.2g / 100ml, decenal 0.15g / 100ml), COD Cr The concentration is 11652 mg / L. The waste alkali solution is acidified with n-pentanoic acid, the pH is adjusted to 3, the acidification temperature is 45-60 degrees Celsius, the centrifugation time is 4 minutes, the speed is 1500 rpm, the oil and water are separated, 39 ml of the oil phase is recovered as a by-product, the lower aqueous phase is 1.96 L, and the COD of the clarified aqueous phase is measured to be 8250 mg / L. Then the aqueous phase is evaporated and concentrated, the temperature is set to 106°C, and the concentration of the carboxylate is 2.5 mol / L. The concentrated solution is electrodialyzed using a three-chamber bipolar membrane electrodialysis device (that is, the dilute acid isolation chamber and the dilute alkali isolation chamber of the five-chamber bipolar membrane electrodialysis device of the present invention are not set, and the remaining structure is similar to the five-chamber bipolar membrane electrodialysis device of the present invention) at a current density of 40 mA / cm 2 The concentrated sodium valerate was converted into NaOH and n-valeric acid. The recovered NaOH solution was 1.4 L with a mass concentration of 5.66 g / 100 ml and a NaOH recovery rate of 86.7%. The recovered n-valeric acid solution was 0.86 L with a concentration of 27.81 g / 100 ml and a n-valeric acid recovery rate of 84.3%.

[0107] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for treating waste alkali liquor from valeraldehyde condensation, characterized in that: The steps include: Step 1, acidifying the valeraldehyde condensation waste alkali solution, and separating the layers to obtain an organic phase and an aqueous phase; Step 2, concentrating the aqueous phase to obtain concentrated water; Step 3, transporting the concentrated water to a five-chamber bipolar membrane electrodialysis device to obtain an organic acid solution and a NaOH solution; The five-chamber bipolar membrane electrodialysis device is provided with an anode electrolysis chamber, a dilute acid isolation chamber, an acid chamber, a central isolation chamber, an alkali chamber, a dilute alkali isolation chamber, and a cathode electrolysis chamber in sequence. The concentrated water is transported to the central isolation chamber. Under the action of the DC electric field, the Na + Entering the alkaline chamber and OH - Combined with NaOH, the carboxylate ions ionized from the concentrated water enter the acid chamber and react with H + The organic acid is generated by combining, and the dilute organic acid in the dilute acid isolation chamber is used as the circulating liquid of the acid chamber, and the dilute NaOH solution in the dilute alkali isolation chamber is used as the circulating liquid of the alkali chamber.

2. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 1, characterized in that: The anode electrolysis chamber is separated from the dilute acid isolation chamber by a cation exchange membrane, and the cathode electrolysis chamber is separated from the dilute alkali isolation chamber by an anion exchange membrane.

3. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 1, characterized in that: The dilute acid isolation chamber and the acid chamber, the dilute alkali isolation chamber and the alkali chamber are separated by bipolar membranes, the acid chamber and the central isolation chamber are separated by an anion exchange membrane, and the alkali chamber and the central isolation chamber are separated by a cation exchange membrane.

4. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 1, characterized in that: The acid used in the acidification treatment is valeric acid; during the acidification treatment, the pH value of the valeraldehyde condensation waste alkali solution is adjusted to 0-6 and the temperature is adjusted to 25-60°C.

5. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 1, characterized in that: The stratification method is centrifugation, the centrifugal speed is 500 to 3000 rpm, and the centrifugal time is 1 to 10 minutes; the organic phase obtained by the stratification is used as a by-product, or the organic phase obtained by the stratification is transported to a distillation tower for separation, and the obtained organic acid is circulated for acidification treatment.

6. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 5, characterized in that: The distillation tower has 30 to 60 plates, 16 to 26 feed plates, a reflux ratio of 1.9 to 2.9, a tower pressure of 5 to 50 kPa, a tower top temperature of 40 to 60°C, and a tower bottom temperature of 120 to 130°C.

7. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 1, characterized in that: When the aqueous phase is concentrated, the obtained distilled water is circulated for preparing the alkali solution used in the valeraldehyde condensation process.

8. The method for treating the valeraldehyde condensation waste alkali liquor according to claim 1, characterized in that: The concentration of sodium carboxylate in the concentrated water is 2-3 mol / L.

9. A system for treating waste alkali liquor from condensation of valeraldehyde, characterized in that: include: Acidification device, used for acidification treatment of valeraldehyde condensation waste alkali liquor; A separation device is connected to the acidification device to separate the acidified valeraldehyde condensation waste alkali solution into layers to obtain an organic phase and an aqueous phase; a concentrating device, connected to the separating device, to concentrate the aqueous phase to obtain concentrated water; A five-chamber bipolar membrane electrodialysis device is connected to the concentrating device. The five-chamber bipolar membrane electrodialysis device is sequentially provided with an anode electrolysis chamber, a dilute acid isolation chamber, an acid chamber, a central isolation chamber, an alkali, a dilute alkali isolation chamber, and a cathode electrolysis chamber. The concentrated water is transported to the central isolation chamber. Under the action of a DC electric field, the Na ionized from the concentrated water is + Entering the alkaline chamber and OH - Combined with NaOH, the carboxylate ions ionized from the concentrated water enter the acid chamber and react with H + The organic acid is generated by combining, and the dilute organic acid in the dilute acid isolation chamber is used as the circulating liquid of the acid chamber, and the dilute NaOH solution in the dilute alkali isolation chamber is used as the circulating liquid of the alkali chamber.

10. The system for treating waste alkali liquor from condensation of valeraldehyde according to claim 9, characterized in that: The anode electrolysis chamber and the dilute acid isolation chamber are separated by a cation exchange membrane, the cathode electrolysis chamber and the dilute alkali isolation chamber are separated by an anion exchange membrane, the dilute acid isolation chamber and the acid chamber, and the dilute alkali isolation chamber and the alkali chamber are separated by bipolar membranes, the acid chamber and the central isolation chamber are separated by an anion exchange membrane, and the alkali chamber and the central isolation chamber are separated by a cation exchange membrane.

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