Extraction column, use method and application of extraction column in winery wastewater treatment

Abstract

The invention discloses an extraction column which comprises a column body and oil-water separation devices arranged at the two ends of the column body. Wherein the organic phase and the water phase form reverse flow in the column body, and the density of the organic phase is smaller than that of the water phase; the oil-water separation device comprises a separation structure with a coalescence function and an inclined guide component. The device solves the interphase entrainment problem that oil at the oil phase outlet at the top of the extraction column carries water and oil at the water phase outlet at the bottom of the extraction column carries water, greatly increases the flooding interval of the extraction column, omits frequent flow adjustment, realizes accurate flow control when the extraction column treats winery wastewater, and has the advantages of wide flooding interval, easy flow control and large treatment capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of organic wastewater treatment, and particularly relates to an extraction column, a using method thereof, and an application thereof in the treatment of winery wastewater. Background Art

[0002] In the production process of the brewing industry, a large amount of wastewater containing complex organic substances is generated. Such winery wastewater usually has the following remarkable characteristics: First, it contains a large amount of organic substances such as alcohols, phenols, and lipids, resulting in extremely high chemical oxygen demand (COD), and the common COD value range is between 5000-30000 mg / L; Second, the water quality fluctuates greatly. Affected by factors such as production processes, raw material types, and production cycles, the composition and concentration of the wastewater often change violently. This characteristic of high COD and large water quality fluctuations makes it impossible for winery wastewater to be directly discharged or reused externally, and it must be properly treated to meet environmental protection requirements or achieve the recycling of water resources.

[0003] At present, for the treatment of winery organic wastewater, mainly biological methods, membrane separation and other methods are used. However, these traditional treatment methods have obvious limitations in practical applications. The biological method relies on the metabolic action of microorganisms to degrade organic substances, but some organic substances in winery wastewater may be toxic or inhibitory to microorganisms, resulting in unstable treatment efficiency. At the same time, biological treatment often requires a long residence time, the treatment facilities cover a large area, and the construction and operation costs are high. The membrane separation method realizes the separation of pollutants through the selective permeability of the membrane, but the membrane is easily polluted and blocked by the organic substances in the wastewater, and the membrane components need to be frequently cleaned and replaced, which not only increases the operation difficulty, but also significantly increases the treatment cost. Moreover, the membrane separation process is usually more complex and difficult to adapt to the characteristics of large fluctuations in the water quality of winery wastewater.

[0004] In view of the deficiencies of traditional methods, the extraction method is an important method for treating organic wastewater. The basic principle of the extraction method is to utilize the solubility difference of the solute in two immiscible liquid phases to transfer the solute from the aqueous phase to the organic phase, thereby achieving the separation and removal of pollutants. This method has been widely applied in the treatment of organic wastewater such as phenol wastewater, coking wastewater, and dye wastewater, and has the advantages of high treatment efficiency and relatively simple operation. In the practical application of the extraction method, the performance of the extraction equipment is crucial. Commonly used extraction equipment includes mixer-settlers, centrifugal extractors, and extraction columns, etc. Among them, the extraction column has been widely favored by the industrial community in recent years due to its advantages such as strong continuity and good sealing performance. However, the operating performance of the extraction column is restricted by a key hydrodynamic parameter, that is, the flooding characteristics. Flooding refers to the phenomenon that during the liquid-liquid extraction process, due to improper operating conditions such as the flow rates, density difference, and interfacial tension of the two phases, the flow state of the two phases in the extraction column becomes disordered, resulting in liquid phase entrainment, backmixing, and even interphase short-circuiting. Once flooding occurs, the separation efficiency of the extraction column will drop sharply, and it may even be unable to operate normally. The flooding phenomenon controls the operating flux of the extraction column. Only by controlling the flow rates of the two phases within the flooding flow rate range can the maximum operating flux, that is, the maximum treatment capacity, be obtained. Therefore, expanding the flooding range of the extraction column has become an important research content in the field of extraction column research.

[0005] Further in-depth analysis of the dilemmas faced by extraction columns in the treatment of winery wastewater in the existing technology reveals that the physical properties of the extraction system are the main controlling factors for controlling the flooding of the extraction column. However, the complex water quality and uneven feed of winery wastewater make the physical property parameters such as density difference and viscosity difference of the extraction system show variable characteristics. When the COD value of the wastewater changes, it means that the types and concentrations of organic substances in the water change, which directly affects the density and viscosity of the aqueous phase; at the same time, wastewater from different batches may contain different proportions of substances such as alcohols, phenols, and lipids, resulting in changes in the interfacial tension between the organic phase and the aqueous phase. These frequent fluctuations in physical property parameters make it extremely difficult to control the flooding flow rate of the extraction column.

[0006] In the traditional design of extraction columns, there is often a lack of adaptability to such water quality fluctuations. When dealing with winery wastewater, operators need to frequently adjust the flow rates of the two phases according to the changes in water quality to avoid the occurrence of flooding. Such frequent adjustments not only increase the complexity and labor intensity of the operation, but also are difficult to achieve precise control, easily leading to unstable operation of the extraction column and large fluctuations in the treatment effect. In addition, due to the lack of an effective entrainment control mechanism, when the flow rates of the two phases are close to the flooding flow rate, water in oil is likely to occur at the oil phase outlet at the top of the extraction column, and oil in water is likely to occur at the water phase outlet at the bottom, further reducing the extraction efficiency and treatment effect.

[0007] In summary, in the prior art, the extraction columns for treating winery wastewater have problems such as narrow flooding intervals, difficulty in adapting to water quality fluctuations, frequent need to adjust the flow rate, and serious interfacial entrainment. The root cause of these problems lies in the mismatch between the complex physical properties of winery wastewater and the structure of traditional extraction columns. Summary of the Invention

[0008] The present invention aims to provide an extraction column, its usage method, and its application in treating winery wastewater, to solve the problem of interfacial entrainment where water is carried in the oil phase at the oil phase outlet at the top of the extraction column and oil is carried in the water phase at the water phase outlet at the bottom of the extraction column, to greatly increase the flooding interval of the extraction column, eliminate the frequent adjustment of the flow rate, achieve precise control of the flow rate when the extraction column treats winery wastewater, and has the advantages of a wide flooding interval, easy flow rate control, and large processing capacity.

[0009] To achieve the above object, the present application provides the following technical solutions:

[0010] An extraction column includes a column body and oil-water separation devices provided at both ends of the column body; wherein, the organic phase and the water phase form a reverse flow in the column body, and the density of the organic phase is less than the density of the water phase; the oil-water separation device includes a separation structure with coalescence function and an inclined guiding component.

[0011] Preferably, the separation structure with coalescence function is used to coalesce the entrained dispersed phase droplets; the inclined guiding component is used to guide the separated liquid phase back to the effective section of the column body; the dynamic oil-water separation device expands the flooding velocity interval of the extraction column through coalescence and diversion effects, and adapts to the fluctuations of wastewater quality.

[0012] Preferably, the separation structure with coalescence function is a grid made of porous coalescence material, and the porous coalescence material includes one of polyethylene, polypropylene, or polyurethane foam.

[0013] Furthermore, the height of the effective section is 3000 mm, and the diameter of the extraction tower is 64 mm.

[0014] In some embodiments, the type of the extraction column is one of a pulsed extraction column, a stirred extraction column, and a common extraction column.

[0015] In some embodiments, that is, the type of the extractant is n-butanol, the diluent is hexane, and the volume ratio of n-butanol is 30%-50%.

[0016] A method for using an extraction column, wherein the organic phase flows in from the bottom of the column and out from the top, and the aqueous phase flows in from the top of the column and out from the bottom. The flow rates of the two phases are precisely adjusted by a flow control device; when entrainment between the two phases occurs due to the flow rates of the two phases, the water-containing organic phase at the top outlet of the column or the oil-containing raffinate water at the bottom outlet flows into the corresponding oil-water separation device, and phase separation is achieved through the coalescence effect of the separation structure and the guiding effect of the inclined guiding component. The separated dispersed phase flows back to the effective section of the column.

[0017] Preferably, the installation direction of the oil-water separation device at the bottom aqueous phase outlet of the column is opposite to that of the oil-water separation device at the top of the column, that is, the inclined guiding component changes from the bottom plate with a certain inclination angle at the bottom of the column to the top plate with a certain inclination angle at the top of the column.

[0018] The inclination angle of the top bottom plate and the inclination angle of the bottom top plate are set in the opposite direction to form a symmetric guiding structure: the water-containing oil phase at the top flows back to the column center along the bottom plate, and the oil-containing oil phase at the bottom flows back to the column center along the top plate, avoiding the impact of the reflux liquid on the main flow field and maintaining the stability of the axial flow.

[0019] Furthermore, the organic phase is a mixed solution of an alcohol-containing extractant and a diluent, wherein the volume ratio of the alcohol is 30% - 50%; the aqueous phase is an alcohol-containing organic wastewater with a COD value of 5000 - 530000 mg / L.

[0020] An application of an extraction column in the treatment of winery wastewater.

[0021] The working principle and beneficial effects of the present invention:

[0022] The extraction column adopts an integrated design of a column body and oil-water separation devices at both ends. The organic phase (with a density less than that of the aqueous phase) flows in from the bottom of the column and out from the top of the column, while the aqueous phase flows in from the top of the column and out from the bottom of the column, forming a countercurrent flow to maximize the mass transfer efficiency. When the flow rates of the two phases approach the flooding threshold, the separation device at the top of the column captures the water microdroplets in the oil phase through the coalescence structure and guides them back to the column body through the inclined guiding component; the separation device at the bottom of the column separates the oil droplets in the aqueous phase and flows them back, forming a dynamic self-adjustment mechanism. Among them, the coalescence structure (such as a porous grid) uses surface tension to make the dispersed phase droplets coalesce and grow, and the inclined guiding component (such as an inclination angle of 15 - 45°) guides the reflux through gravity phase separation. When the flow rate increases and causes entrainment, after the water-containing oil phase at the top of the column is coalesced, the aqueous phase flows back along the inclination angle of the bottom plate and the oil phase flows out; after the oil-containing oil phase at the bottom of the column is coalesced, the oil phase flows back along the inclination angle of the top plate and the aqueous phase flows out.

[0023] Therefore, the present application successfully solves the problem of entrainment between phases where there is water in the oil at the oil phase outlet at the top of the extraction column and oil in the water at the aqueous phase outlet at the bottom of the extraction column, greatly improves the flooding range of the extraction column, eliminates the need for frequent flow rate adjustment, realizes precise flow control when the extraction column treats winery wastewater, and has the advantages of a wide flooding range, easy flow control, and large processing capacity. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the extraction column structure. Specific implementation manners

[0025] The following is a further detailed description through specific implementation manners:

[0026] Example 1: Provide an extraction column with a wide operating range and its application in the treatment of winery wastewater. Select the wastewater of a certain winery, control the COD value of the organic wastewater at about 5000 mg / L through processes such as dilution and distillation, configure an organic solvent of n-butanol / hexane with a volume ratio of 30%, fix the flow rate of the organic phase at 5 mm / s, and investigate the flooding velocity of the dispersed phase under the condition that an oil-water separation device is installed at the top and bottom of the column. The results show that the apparent flooding velocity of the dispersed phase is 11.25 mm / s.

[0027] And the following comparative experiments were designed: Refer to Table 1

[0028] Table 1 Flooding velocities of the extraction column under different conditions

[0029]

[0030]

[0031] The following conclusions are obtained from Table 1:

[0032] (1) When COD = 5084 mg / L and the proportion of n-butanol is 40%, the flooding velocity of Example 5 with the installed device is 11.06 mm / s, while that of Comparative Example 1 without installation is only 6.32 mm / s, with an increase of 75%; when COD rises to 30104 mg / L, Example 8 (6.84 mm / s) has an increase of 158% compared to Comparative Example 4 (2.65 mm / s). That is, the oil-water separation device significantly expands the flooding range through the coalescence-diversion mechanism, especially with more obvious advantages under high COD conditions, verifying the technical effectiveness of "dynamic self-regulation and flooding control".

[0033] (2) When the proportion of n-butanol is 30%, as COD increases from 5084 mg / L to 30104 mg / L, the flooding velocity decreases from 11.25 mm / s to 7.81 mm / s, with a decrease of 30.6%; when the proportion of n-butanol is 50%, as COD increases from 5084 mg / L to 30104 mg / L, the flooding velocity decreases from 10.11 mm / s to 6.01 mm / s, with a decrease of 40.6%.

[0034] The higher the COD value is, the greater the decline in the flooding velocity. Since the concentration of organic matter in high-COD wastewater is high, it leads to an increase in the viscosity of the aqueous phase and a decrease in the density difference, exacerbating the interfacial flow resistance. Under high-COD conditions, the traditional extraction column needs to significantly reduce the flow rate (for example, the flow rate in Comparative Example 4 is only 2.65 mm / s). However, through device compensation in the present invention, a flow rate of 6.01 mm / s can still be maintained when COD = 30104 mg / L, and the throughput is increased by 127%, adapting to the high-COD fluctuation characteristics of winery wastewater.

[0035] (3) When the device is not installed, the upper limit of the safe flow rate for COD = 5084 mg / L is 6.32 mm / s; after the device is installed, the upper limit of the safe flow rate is increased to 11.25 mm / s, and the operating range is expanded by 78%, which means that the throughput per unit time can be increased by 78%.

[0036] (4) When COD increases from 5084 mg / L to 30104 mg / L, the decrease in the flooding velocity of the installed device is 37.7%, and the decrease in the case without the installed device reaches 57.4%. This shows that the anti-fluctuation ability of the present invention is improved by 34%, and there is no need to frequently adjust the flow rate, adapting to the uneven incoming material characteristics of winery wastewater.

[0037] In summary, based on the data, when treating winery wastewater (COD = 10000 mg / L) with a throughput of 100 m 3 / h, the extraction column of the present invention can save 3 parallel devices compared with the traditional equipment, and the equipment investment is reduced by 45%.

[0038] The above are only examples of the present invention, and common knowledge such as the specific structure and characteristics known in the solution is not described in detail here. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several modifications and improvements can still be made, and these should also be regarded as the protection scope of the present invention, which will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application should be based on the content of its claims, and the specific implementation manners described in the specification can be used to explain the content of the claims.

Claims

1. An extraction column, characterized in that, It includes a column body and oil-water separation devices arranged at both ends of the column body; wherein, the organic phase and the water phase form a countercurrent flow in the column body, and the density of the organic phase is less than that of the water phase; the oil-water separation device includes a separation structure with coalescence function and an inclined guiding component.

2. The extraction column according to claim 1, wherein, The separation structure with coalescence function is used for coalescing entrained dispersed-phase droplets; The inclined guiding component is used to guide the separated liquid phase to flow back to the effective section of the column body; The oil-water separation device expands the flooding velocity range of the extraction column through coalescence and diversion effects to adapt to the fluctuation of wastewater quality.

3. The extraction column according to claim 2, wherein The separation structure with coalescence function is a grid made of porous coalescence material, and the porous coalescence material includes one of polyethylene, polypropylene or polyurethane foam.

4. The extraction column according to claim 3, characterized in that, The structural parameters of the extraction column are: the height of the effective section is 3000 mm, and the diameter of the extraction tower is 64 mm.

5. The extraction column according to claim 4, characterized in that, The type of the extraction column is one of a pulsed extraction column, a stirred extraction column and common extraction columns.

6. The extraction column according to claim 5, wherein, That is, the type of the extractant is n-butanol, the diluent is hexane, and the volume ratio of n-butanol is 30%-50%.

7. A method for using an extraction column according to any one of claims 1-5, characterized in that, The organic phase flows in from the bottom of the column body and flows out from the top, and the water phase flows in from the top of the column body and flows out from the bottom. The flow rates of the two phases are precisely adjusted by a flow control device; when the interphase entrainment is caused by the flow rates of the two phases, the water-containing organic phase at the top outlet of the column body or the oil-containing raffinate water at the bottom outlet flows into the corresponding oil-water separation device. Phase separation is achieved through the coalescence effect of the separation structure and the diversion effect of the inclined guiding component, and the separated dispersed phase flows back to the effective section of the column body.

8. The method for using the extraction column according to claim 6, characterized in that The installation direction of the oil-water separation device at the bottom water phase outlet of the tower is opposite to that of the oil-water separation device at the top of the tower, that is, the inclined guiding component changes from the bottom plate with a certain inclination angle at the tower bottom to the top plate with a certain inclination angle at the tower top.

9. The method for using an extraction column according to claim 7, characterized in that The organic phase is a mixed solution of an alcohol-containing extractant and a diluent, wherein the volume ratio of the alcohol is 30% to 50%; the water phase is an alcohol-containing organic wastewater with a COD value of 5000 to 530000 mg / L.

10. The application of the extraction column according to any one of claims 1 to 5 in the treatment of winery wastewater.

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