Wide-temperature-range reverse demulsifier as well as preparation method and use method thereof

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a wide-temperature-range reverse demulsifier as well as a preparation method and a use method of the wide-temperature-range reverse demulsifier. The additive is prepared from the following components: 25 to 35 percent of modified galactomannan polysaccharide, 15 to 20 percent of modified block polyether, 8 to 12 percent of fatty alcohol-polyoxyethylene ether mixture, 3 to 5 percent of phosphate surfactant, 1 to 2 percent of nano zinc oxide, 0.6 to 0.8 percent of sodium silicate and the balance of mixed solvent, when the wide-temperature-range reverse demulsifier is used, the wide-temperature-range reverse demulsifier is directly added into pretreated oily wastewater, stirring is performed at a high speed for 10-15 min, then stirring is performed at a low speed for 5-10 min, and finally standing is performed for 30 min or above. Compared with the prior art, the prepared wide-temperature-range reverse demulsifier has the advantages that the low-temperature stability and the oil removal rate are improved, the preparation process and the use method are simple, and the wide-temperature-range reverse demulsifier is suitable for industrial production. When the demulsifying agent is used, quick demulsification of the oily wastewater in a low-temperature environment can be realized without additionally adding a flocculating agent, so that the use dosage is reduced, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and particularly to a wide-temperature-range reverse demulsifier and its preparation and use methods. Background Art

[0002] With the rapid development of industry, the discharge of oily wastewater is increasing day by day. Oily wastewater mainly comes from industries such as petroleum, chemical engineering, iron and steel, and coking, and contains a large amount of pollutants such as crude oil, emulsified oil, and dispersed oil. These oily wastewaters not only cause serious pollution to the environment but also waste a large amount of precious resources. Traditional methods for treating oily wastewater include physical methods, chemical methods, and biological methods, etc. However, these methods have certain limitations when treating high-concentration and difficult-to-degrade oily wastewater. For example, physical methods are difficult to remove tiny oil droplets, chemical methods will produce secondary pollution, and biological methods have a long treatment cycle and high requirements for water quality. Therefore, developing an efficient, environmentally friendly, and economical method for treating oily wastewater has important practical significance.

[0003] Reverse demulsifiers are key chemicals used for oil-water separation. As chemical substances capable of destroying the oil-water interfacial film, they have broad application prospects and are widely used in the treatment of fields such as oilfield produced water, fracturing flowback fluid, and refining wastewater. However, the existing reverse demulsifiers have unsatisfactory demulsification effects in special environments and a narrow application range, which limits their application in actual production.

[0004] In the prior art, block polyether demulsifiers are widely used due to their good interfacial activity, but their low-temperature performance is still insufficient. Patent CN117603444A proposes a demulsifier based on ethylene oxide-propylene oxide block polyether, but its demulsification speed is slow in low-temperature environments and its adaptability to high-salinity wastewater is poor. In addition, Patent CN101716475B provides a reverse demulsifier for the field of crude oil production and processing and its preparation method. By introducing quaternary ammonium salt-modified polyether, the demulsification effect is improved. Although it has good interfacial participation ability and viscosity reduction effect and has good demulsification performance for oil-in-water emulsions, it can be used for low-temperature dehydration of reverse emulsions or oily sewage treatment, but its preparation process is complex, the production cost is high, and in the actual treatment process, the prepared reverse demulsifier also needs to be used in combination with a flocculant. Patent CN109628139A discloses a preparation method of a reverse demulsifier for treating heavy oil produced fluid. Using fatty alcohol as the initiator to react with propylene oxide and ethylene oxide to prepare fatty alcohol polyoxypropylene-oxyethylene ether, then reacting with 2-bromo-isobutyryl bromide to prepare 2-bromo-isobutyrate, and finally reacting with organic amine to prepare the reverse demulsifier, which can improve the oil-water separation effect, but it is not suitable for use at low temperatures, and pyridine is used in the preparation process, which is a toxic substance and will cause harm to the human body and the environment and is difficult to industrialize.

[0005] It can be seen that traditional reverse demulsifiers have a narrow applicable temperature range and have problems such as slow demulsification speed and low oil-water separation efficiency in low-temperature environments (such as below 25°C). Especially for high salinity oily wastewater with high viscosity at low temperatures, the demulsification effect at low temperatures decreases significantly, and the preparation process is complex. When in use, additional additives such as polyacrylamide need to be added, resulting in high usage costs. Therefore, it is of great practical significance to develop a reverse demulsifier with a wide applicable temperature range that can quickly demulsify and has a simple preparation process and low cost in low-temperature environments. Summary of the Invention

[0006] In order to solve the problems of slow demulsification speed and low oil-water separation efficiency of existing reverse demulsifiers in low-temperature environments, the present invention provides a wide-temperature-range reverse demulsifier and its preparation and use methods, which can achieve rapid demulsification and oil-water separation of high salinity oily wastewater in a wide temperature range of 5 - 45°C, improve the demulsification speed and oil-water separation efficiency, simplify the preparation process, and reduce the production cost.

[0007] A wide-temperature-range reverse demulsifier, by mass percentage, consists of the following components: 25 - 35% of modified galactomannan polysaccharide, 15 - 20% of modified block polyether, 8 - 12% of fatty alcohol polyoxyethylene ether mixture, 3% - 5% of phosphate ester surfactant, 1% - 2% of nano-zinc oxide, 0.6 - 0.8% of sodium silicate, and the balance being a mixed solvent.

[0008] Further, the modified galactomannan polysaccharide is obtained by modifying galactomannan polysaccharide derivatives with glycidyltrimethylammonium chloride, and the galactomannan polysaccharide derivatives are obtained by polymerizing propylene oxide, ethylene oxide, and guar gum.

[0009] Further, the modified block polyether is obtained by modifying block polyether with allyltrimethylammonium chloride, and the block polyether is formed by block polymerization of propylene oxide and ethylene oxide.

[0010] Further, the fatty alcohol polyoxyethylene ether mixture consists of at least one low-carbon-chain fatty alcohol polyoxyethylene ether with a carbon chain length of C8 - 10 and at least one high-carbon-chain fatty alcohol polyoxyethylene ether with a carbon chain length of C12 - 16;

[0011] The low-carbon-chain fatty alcohol polyoxyethylene ethers include octyldecanol polyoxyethylene 4 ether, octyldecanol polyoxyethylene 6 ether, and isooctanol polyoxyethylene ether; the high-carbon-chain fatty alcohol polyoxyethylene ethers include lauryl alcohol polyoxyethylene 9 ether, lauryl alcohol polyoxyethylene 7 ether, lauryl alcohol polyoxyethylene 23 ether, and cetyl alcohol polyoxyethylene ether.

[0012] Further, the phosphate surfactant is any one of polysiloxane-modified phosphate, distearyl phosphate, dioctyl phosphate, diisobutyl phosphate, didodecyl phosphate, and sorbitol phosphate.

[0013] Further, the mixed solvent is a mixed solvent of propylene glycol methyl ether and hexylene glycol, wherein the volume ratio of propylene glycol methyl ether to hexylene glycol is 1:1 to 3:1.

[0014] The present invention also provides a preparation method of the above-mentioned wide-temperature-range reverse demulsifier, which includes the following steps:

[0015] Step 1. At room temperature, add the formulated amount of modified block polyether, phosphate surfactant, and fatty alcohol polyoxyethylene ether mixture into a reaction kettle and stir to mix to obtain a mixed system;

[0016] Step 2. Slowly heat the mixed system in Step 1 to 40 - 60 °C, add the formulated amount of mixed solvent, continue to stir for 10 - 20 min to obtain a homogeneous solution, and then cool it to room temperature;

[0017] Step 3. Add the formulated amount of modified galactomannan polysaccharide into the homogeneous solution in Step 2, slowly heat it to 35 - 45 °C, and continue to stir for 10 - 30 min;

[0018] Step 4. After the stirring is completed, add the formulated amount of nano-zinc oxide and sodium silicate into the system in Step 3, slowly heat it to 60 - 70 °C, and stir for 15 - 30 min to obtain the wide-temperature-range reverse demulsifier.

[0019] Further, the preparation process of the modified galactomannan polysaccharide is as follows:

[0020] (1) In a high-pressure reaction kettle, disperse guar gum in an isopropyl alcohol aqueous solution and a sodium hydroxide aqueous solution to obtain a dispersion;

[0021] (2) Add propylene oxide and ethylene oxide to the dispersion obtained in Step (1), react at a temperature of 70 °C and a pressure of 0.2 MPa for 3 h. After the reaction is completed, cool it to 50 °C;

[0022] (3) Add an aqueous solution of glycidyltrimethylammonium chloride to the system cooled in Step (2), and react at 50 °C for 3 h;

[0023] (4) After the reaction is completed, neutralize the reaction mixture with concentrated hydrochloric acid, dilute it with an isopropyl alcohol aqueous solution, neutralize it at room temperature for 1 h, then pour the reaction solution into methanol, precipitate and filter the reaction product to separate it. Wash the obtained precipitate with an aqueous methanol solution, and dry the reaction product under reduced pressure to obtain the modified galactomannan polysaccharide.

[0024] Further, the preparation process of the modified block polyether is as follows:

[0025] First, propylene oxide and ethylene oxide are mixed in a certain proportion, and propylene glycol and NaOH are added. Block polymerization is carried out at a temperature of 100 - 120 °C and a pressure of 0.1 - 0.3 MPa for 8 - 12 h to obtain block polyether;

[0026] Then, the block polyether and allyl trimethyl ammonium chloride are reacted at a temperature of 60 - 80 °C and a pressure of 0.1 - 0.3 MPa for 2 - 4 hours to obtain the modified block polyether;

[0027] Among them, the mass ratio of block polyether to allyl trimethyl ammonium chloride is 1:0.5 - 1:2, and the mass ratio of propylene oxide to ethylene oxide is 3:1 - 5:1.

[0028] In addition, the present invention also provides a method for using the above-mentioned wide-temperature-range reverse demulsifier and the reverse demulsifier prepared by the above-mentioned preparation method, which is specifically as follows:

[0029] The wide-temperature-range reverse demulsifier is directly added to the pretreated oily wastewater. First, it is stirred at a high speed for 10 - 15 min, then stirred at a low speed for 5 - 10 min, and finally left standing for more than 30 min, so as to realize the rapid demulsification and oil-water separation treatment of oily wastewater at low temperature;

[0030] The addition amount is 50 ppm - 200 ppm, the speed of high-speed stirring is 100 - 300 r / min, and the speed of low-speed stirring is 30 - 60 r / min.

[0031] The advantages of the present invention are as follows:

[0032] 1. The wide-temperature-range reverse demulsifier of the present invention has both demulsification and flocculation functions, has a wide temperature application range, can be used at low temperature, and does not require additional addition of polyacrylamide during use. By introducing modified galactomannan and modified block polyether, it can act at the oil-water interface, significantly improving the interfacial activity of the demulsifier in a low-temperature environment, enhancing its interaction with oil droplets and other impurities in water, and being able to adsorb more effectively on the surface of oil droplets at low temperature, reducing the interfacial tension between oil droplets and water, increasing the attraction between oil droplets, promoting the coalescence of oil droplets, accelerating the separation of the oil phase from the water phase, and being able to achieve oil-water separation in a shorter time, with the demulsification speed increased by more than 30%. At the same time, it can play a flocculation role at low temperature, flocculating the coalesced oil droplets and other suspended impurities into large flocs, so as to facilitate solid-liquid separation through methods such as precipitation and filtration, achieving the purpose of purifying wastewater;

[0033] 2. The reverse demulsifier prepared by the present invention achieves the effect of rapid demulsification at low temperature under the synergistic action of multiple components. The fatty alcohol polyoxyethylene ether mixture and phosphate surfactant can reduce the interfacial tension and assist the modified galactomannan and modified block polyether to improve the flocculation effect in a low-temperature and high-salinity environment; the phosphate surfactant can improve the viscosity, fluidity and salt resistance of high-salinity oily wastewater at low temperature, and nano-zinc oxide can improve the dispersibility. There is a chelating effect between nano-zinc oxide and the phosphate surfactant, which can increase the low-temperature stability of the reverse demulsifier while improving the fluidity and dispersibility, and at the same time can cooperate with other components to produce faster adsorption and improve the demulsification efficiency at low temperature. The addition of sodium silicate can cooperate with other components to enhance the adsorption and flocculation effects. The present invention is applicable to the treatment of high-salinity oily wastewater with a temperature of 5-45°C and a salinity > 10 g / L. Compared with the prior art, it has low-temperature stability, a wide temperature application range, strong adaptability, significantly improves the oil-water separation efficiency and oil removal rate in a low-temperature environment, and at the same time the preparation process and usage method are simple, reducing the production cost. Brief Description of the Drawings

[0034] Figure 1 It is a comparison diagram of the water sample state after the wide-temperature-range reverse demulsifier of Example 1 of the present invention is just shaken evenly;

[0035] Figure 2 It is a comparison diagram of the water sample state after the wide-temperature-range reverse demulsifier of Example 1 of the present invention is shaken evenly and left standing for 5 minutes;

[0036] Figure 3 It is a comparison diagram of the water sample state after the wide-temperature-range reverse demulsifier of Example 1 of the present invention is shaken evenly and left standing for 20 minutes;

[0037] Figure 4 It is a graph showing the change trend of the oil removal rate with the standing time of the wide-temperature-range reverse demulsifier of Example 1 of the present invention at different temperatures. Detailed Embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] It should be noted that the installation methods and technical terms mentioned in the present invention are all well-known technical terms in the technical field, so no further explanation will be made. In addition, the same reference numerals are used for the same components, but this does not affect nor should it constitute an accurate understanding of the technical solution by those skilled in the art.

[0040] Example 1

[0041] This example provides a wide-temperature-range demulsifier for reverse phase, which is composed of the following components by mass percentage: 30% of modified galactomannan polysaccharide, 15% of modified block polyether, 9% of fatty alcohol polyoxyethylene ether mixture (the fatty alcohol polyoxyethylene ether mixture in this example is octyldecanol polyoxyethylene 6 ether and lauryl alcohol polyoxyethylene 9 ether), 3% of phosphate surfactant (the phosphate surfactant in this example is didodecyl phosphate), 1.5% of nano-zinc oxide, 0.6% of sodium silicate, and the balance is a mixed solvent (the mixed solvent in this example is propylene glycol methyl ether and hexylene glycol with a volume ratio of 3:1);

[0042] The preparation method of the modified galactomannan polysaccharide is as follows:

[0043] (1) In a high-pressure reactor, 80 g of guar gum is dispersed in 450 mL of isopropyl alcohol aqueous solution (80 vol%) and 5.4 g of sodium hydroxide aqueous solution (48 wt%) to obtain a dispersion;

[0044] (2) 120 g of propylene oxide and 30 g of ethylene oxide are added to the dispersion obtained in step (1), and the reaction is carried out at a temperature of 70 °C and a pressure of 0.2 MPa for 3 h. After the reaction is completed, it is cooled to 50 °C;

[0045] (3) 75 g of aqueous solution of glycidyltrimethylammonium chloride (80 wt%) is added to the system cooled in step (2), and the reaction is carried out at 50 °C for 3 h;

[0046] (4) After the reaction is completed, the reaction mixture is neutralized with 7 g of concentrated hydrochloric acid (concentration 35%), and diluted with 750 mL of isopropyl alcohol aqueous solution. After neutralization at room temperature for 1 h, the reaction solution is poured into 400 mL of methanol and stirred to obtain a precipitate. The reaction product precipitate is filtered and separated, and the obtained precipitate is washed with methanol aqueous solution, and then dried under reduced pressure to obtain the modified galactomannan polysaccharide.

[0047] The preparation process of the modified block polyether is as follows:

[0048] First, 3 g of propylene glycol and 0.05 g of NaOH are added to the reaction kettle. After nitrogen replacement, the temperature is slowly raised to 100 °C, and then 45 g of propylene oxide and 15 g of ethylene oxide are slowly added according to (3:1). Block polymerization is carried out at a temperature of 100 °C and a pressure of 0.2 MPa for 12 h to obtain a block polyether;

[0049] Then, the block polyether and allyltrimethylammonium chloride are added to the reaction kettle in a mass ratio of 1:1, and the reaction is carried out at a temperature of 60 °C and a pressure of 0.2 MPa for 2 hours to obtain the modified block polyether.

[0050] The preparation method of the wide-temperature-range reverse demulsifier comprises the following steps:

[0051] Step 1. At room temperature, 15% of modified block polyether, 3% of didodecyl phosphate, and 9% of octyldecanol polyoxyethylene 6 ether and lauryl alcohol polyoxyethylene 9 ether are added to a reaction kettle and stirred and mixed to obtain a mixed system;

[0052] Step 2. The mixed system in Step 1 is slowly heated to 60 °C, and a formulated amount of propylene glycol methyl ether and hexylene glycol mixed solvent (volume ratio 3:1) is added, and stirring is continued for 10 min to obtain a homogeneous solution, and then it is cooled to room temperature;

[0053] Step 3. 30% of modified galactomannan polysaccharide is added to the homogeneous solution in Step 2, and it is slowly heated to 35 °C, and stirring is continued for 20 min;

[0054] Step 4. After the stirring is completed, 1.5% of nano-zinc oxide and 0.6% of sodium silicate are added to the system in Step 3, and it is slowly heated to 60 °C and stirred for 25 min to obtain the wide-temperature-range reverse demulsifier.

[0055] Example 2

[0056] The raw material components and preparation method of the wide-temperature-range reverse demulsifier described in this example are the same as those in Example 1, the difference is that the dosages of each component are different, and it is composed of the following components: 25% of modified galactomannan polysaccharide, 15% of modified block polyether, 8% of fatty alcohol polyoxyethylene ether mixture (the fatty alcohol polyoxyethylene ether mixture in this example is isooctyl alcohol polyoxyethylene ether, lauryl alcohol polyoxyethylene 7 ether, and lauryl alcohol polyoxyethylene 23 ether), 3% of phosphate surfactant (the phosphate surfactant in this example is dioctyl phosphate and dicetyl phosphate), 1% of nano-zinc oxide, 0.6% of sodium silicate, and the balance is a mixed solvent (the mixed solvent in this example is propylene glycol methyl ether and hexylene glycol with a volume ratio of 2:1).

[0057] Example 3

[0058] The raw material components and preparation method of the wide-temperature-range demulsifier in this example are the same as those in Example 1, except that the dosages of each component are different. By mass percentage, it consists of the following components: 35% of modified galactomannan polysaccharide, 20% of modified block polyether, 12% of fatty alcohol polyoxyethylene ether mixture (the fatty alcohol polyoxyethylene ether mixture in this example is octyldecanol polyoxyethylene 4 ether and cetyl alcohol polyoxyethylene ether), 5% of phosphate surfactant (the phosphate surfactant in this example is sorbitol phosphate), 2% of nano-zinc oxide, 0.8% of sodium silicate, and the balance is a mixed solvent (the mixed solvent in this example is propylene glycol methyl ether and hexylene glycol with a volume ratio of 1:1).

[0059] Example 4

[0060] The raw material components and preparation method of the wide-temperature-range demulsifier described in this example are the same as those in Example 1, except that the parameter conditions in the preparation process are different:

[0061] In the preparation process of the modified block polyether in this example: the mass ratio of propylene oxide to ethylene oxide is 5:1, the polymerization temperature is 120 °C, the pressure is 0.1 MPa, and the polymerization reaction time is 8 h; the mass ratio of block polyether to allyltrimethylammonium chloride is 1:2, the modification temperature is 80 °C, the pressure is 0.1 MPa, and the modification reaction time is 4 h;

[0062] In the preparation process of the wide-temperature-range demulsifier in this example: the temperature in Step 2 is 40 °C and the stirring time is 20 min; the temperature in Step 3 is 40 °C and the stirring time is 15 min; the temperature in Step 4 is 70 °C and the stirring time is 15 min;

[0063] Example 5

[0064] The raw material components and preparation method of the wide-temperature-range demulsifier described in this example are the same as those in Example 1, except that the parameter conditions in the preparation process are different:

[0065] In the preparation process of the modified block polyether in this example: the mass ratio of propylene oxide to ethylene oxide is 4:1, the polymerization temperature is 110 °C, the pressure is 0.3 MPa, and the polymerization reaction time is 8 h; the mass ratio of block polyether to allyltrimethylammonium chloride is 1:0.5, the modification temperature is 60 °C, the pressure is 0.3 MPa, and the modification reaction time is 3 h;

[0066] In the preparation process of the wide-temperature-range demulsifier in this example: the temperature in Step 2 is 50 °C and the stirring time is 15 min; the temperature in Step 3 is 45 °C and the stirring time is 10 min; the temperature in Step 4 is 70 °C and the stirring time is 30 min;

[0067] Comparative Example 1

[0068] The preparation method and usage method of the wide-temperature-range reverse demulsifier described in this comparative example are the same as those in Example 1, except that the raw material compositions are different. The modified galactomannan is not added to the wide-temperature-range reverse demulsifier described in this comparative example.

[0069] Comparative Example 2

[0070] The preparation method and usage method of the wide-temperature-range reverse demulsifier described in this comparative example are the same as those in Example 1, except that the raw material compositions are different. The modified block polyether is not added to the wide-temperature-range reverse demulsifier described in this comparative example.

[0071] Comparative Example 3

[0072] The preparation method and usage method of the wide-temperature-range reverse demulsifier described in this comparative example are the same as those in Example 1, except that the raw material compositions are different. The phosphate ester surfactant is not added to the wide-temperature-range reverse demulsifier described in this comparative example.

[0073] Comparative Example 4

[0074] The preparation method and usage method of the wide-temperature-range reverse demulsifier described in this comparative example are the same as those in Example 1, except that the raw material compositions are different. The mixture of nano-zinc oxide and fatty alcohol polyoxyethylene ether is not added to the wide-temperature-range reverse demulsifier described in this comparative example.

[0075] Experimental Example 1

[0076] Referring to the China National Petroleum and Natural Gas Industry Standard SY / T 5797-93 "Evaluation Method for the Performance of Demulsifiers for Oil-in-Water Emulsions", an indoor evaluation was carried out on the oil-containing water sample (mineralization degree 12.088 g / L) generated during the production process of Changqing Oilfield. 6 portions of 100 mL of the oil-water sample were taken into 6 test tubes respectively, and shaken well in a constant temperature water bath at 25°C for 10 min. The medicaments of the examples and comparative examples with a concentration of 50 ppm were added dropwise into the 6 test tubes with a syringe respectively, and shaken manually to mix them thoroughly, then left to stand for stratification. The water color and flocculation speed were observed, and the oil content values before and after adding the medicine were measured, and the oil removal rate was calculated (the calculation formula for the oil removal rate is: where W O1 is the initial oil volume, and W O2 is the remaining oil volume), and the results are shown in Table 1:

[0077] Table 1 Performance Test Table of Reverse Demulsifiers

[0078]

[0079] It can be seen from the data in Table 1 that the oil removal rate of the inverse demulsifier obtained by the preparation method of Examples 1-5 of the present invention can reach more than 85% after standing for 20 minutes, and can reach more than 90% after standing for 30 minutes, and the effect of Example 1 is the best, which is not the optimal embodiment of the present application. The oil removal rate of the inverse demulsifier obtained by the preparation method of Comparative Examples 1-4 can only reach a maximum of 60% after standing for 20 minutes, and the oil removal rate can only reach more than 70% after standing for 30 minutes. Compared with the results of this embodiment, the inverse demulsifier prepared in the comparative example has a poor oil removal effect and a slow demulsification speed at the same dosage and temperature.

[0080] Since the modified galactomannan, modified block polyether, phosphate surfactant, nano zinc oxide and fatty alcohol polyoxyethylene ether mixture in the formula of comparative examples 1-4 do not exist at the same time, while the five exist at the same time in the formula composition of embodiments 1-5, it means that the combination of the five produces a good synergistic effect in the separation and treatment of oily wastewater. The lack of any one of the components will affect the comprehensive performance of the reverse demulsifier, causing the oil removal rate and demulsification rate to decrease in the separation of oily wastewater at room temperature, further resulting in a worse demulsification effect at low temperature.

[0081] Experimental Example 2

[0082] The water sample without adding the agent was used as the blank group, the water sample with the commercially available BXG-419 inverse demulsifier (purchased from Hubei Benxin Environmental Protection Technology Co., Ltd.) was used as the control group, and the wide temperature range inverse demulsifier prepared in Example 1 of the present application was used as the experimental group for indoor experiments. The test evaluation method was as follows:

[0083] Pour the experimental water sample into a test tube with a volume of 50ml. Simulate the temperature on site by lowering it to 20℃. Add the three reagents to be evaluated respectively with a concentration of 50ppm. Shake it by hand 20 times to examine the water color and oil-water separation speed. Take photos at intervals to record the water sample status. The results are as follows: Figures 1-3 As shown ( Figure 1 This is the water-like state after adding the reagent and shaking it well. Figure 2 The water sample state after 5 minutes of shaking. Figure 3 The figure shows the state of the water sample 20 minutes after shaking), from left to right are the control group, the experimental group and the blank group. It can be seen from the figure that the water sample of the blank group without adding the agent is not clear, and the water sample of the experimental group with the wide temperature range reverse demulsifier prepared in Example 1 is clear, and the final clarification effect is better than the control group of the existing reverse demulsifier BXG-419.

[0084] Experimental Example 3

[0085] The wide temperature range inverse demulsifier prepared in the best embodiment 1 was tested for temperature adaptability, and the test process was as follows:

[0086] First, simulate oily wastewater in the laboratory. Take industrial waste oil (salinity > 10 g / L) and deionized water at a volume ratio of oil to water of 1:9, and mix them at a high speed of 5000 rpm for 10 min to form a stable oil-in-water emulsion with an initial oil content of 10%.

[0087] Then, dilute the wide-temperature-range reverse demulsifier prepared in Example 1 to prepare an emulsion with a concentration of 50 ppm, and add it to the prepared oil-in-water (O / W) emulsion. Place them in a constant-temperature water bath at 5°C, 15°C, 25°C, 35°C, and 45°C respectively, and record the change trend of the oil removal rate with the standing time at different temperatures. The results are as Figure 4 shown.

[0088] It can be Figure 4 seen that the wide-temperature-range reverse demulsifier prepared by the present invention has wide-temperature-range adaptability and can achieve oil-water separation within the temperature range of 5°C to 45°C. The oil removal rate shows an increasing trend with the increase of temperature and time. The final oil removal rate at 5°C can reach more than 70%, the final oil removal rate at 15°C can reach more than 80%, the final oil removal rate at 25°C can reach more than 85%, the final oil removal rate at 35°C can reach more than 90%, and the final oil removal rate at 45°C can still reach more than 95%. The applicable temperature range is relatively wide and is suitable for areas with large seasonal temperature differences. Although the performance at low temperature decreases slightly, it can still maintain high oil removal efficiency and good stability, and is also suitable for the treatment of high-salinity oily wastewater in low-temperature environments.

[0089] Experimental Example 4

[0090] Test the demulsification ability and oil-water separation efficiency of the wide-temperature-range reverse demulsifier prepared in the optimal Example 1 at a low temperature of 5°C. The test process is as follows:

[0091] Take a small amount of the oil-in-water emulsion prepared in Example 3 and put it into 3 test tubes respectively. Pre-cool it in a low-temperature water bath (5°C) for 30 min, and add the reverse demulsifier agents prepared in Example 1 with concentrations of 50 ppm, 100 ppm, and 200 ppm respectively. After shaking well, let it stand. Measure the volume of the upper oil phase every 10 min, calculate the oil removal rate, and record the time required for the oil phase to completely float and the water phase to become clear. The results are shown in Table 2:

[0092] Table 2 Separation effects of the agent in Example 1 at different concentrations

[0093]

[0094] It can be seen from the test results that the wide-temperature-range reverse demulsifier of the present invention is applicable to the treatment of oily wastewater in low-temperature environments. Its oil removal rate increases with the increase of concentration, and the demulsification speed increases with the increase of concentration. When the dosage is 50 ppm, the oil removal rate at a low temperature of 5 °C is 70%, the oil removal time is 60 min, and the residual oil content is <100 mg / L. When the applicable dosage is increased to 100 ppm, the separation time is shortened to 35 min, and the oil removal rate is increased to 85%. It has good stability at low temperatures and also has the ability of rapid demulsification and flocculation.

[0095] In practical applications, the usage method is as follows:

[0096] (1) Preliminarily filter the high-salinity (>10 g / L) oily wastewater in a wide temperature range (<25 °C), remove the settled large particle impurities and suspended solids, and add acid-base regulators to make the pH value of the oily wastewater between 6 and 9;

[0097] (2) Add 50 ppm - 200 ppm of the above-mentioned wide-temperature-range reverse demulsifier to the oily wastewater after adjusting the pH value. First, stir at a stirring speed of 200 r / min for 15 min, and then stir at a speed of 60 r / min for 10 min to make the demulsified oil droplets and other suspended solids fully contact and form large flocs;

[0098] (3) After stirring, let it stand for more than 30 min, and let the flocs naturally precipitate under the action of gravity to separate the oil phase, water phase and flocculated solid impurities;

[0099] (4) Further treat or discharge the separated oil phase, water phase and solid impurities according to safety specifications and environmental protection requirements.

[0100] For those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0101] The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any minor modifications, equivalent replacements and improvements made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A wide temperature range inverse demulsifier, characterized in that: The composition is composed of the following components by mass percentage: 25-35% of modified galactomannan polysaccharide, 15-20% of modified block polyether, 8-12% of fatty alcohol polyoxyethylene ether mixture, 3%-5% of phosphate surfactant, 1%-2% of nano zinc oxide, 0.6-0.8% of sodium silicate, and the balance is a mixed solvent; The application scenario of the wide temperature range reverse demulsifier is to treat oily wastewater with a temperature of 5 to 45°C and a mineralization of more than 10 g / L.

2. The wide temperature range inverse demulsifier according to claim 1, characterized in that: The modified galactomannan polysaccharide is obtained by modifying a galactomannan polysaccharide derivative with glycidyl trimethylammonium chloride, and the galactomannan polysaccharide derivative is obtained by polymerizing propylene oxide, ethylene oxide and fennel gum.

3. The wide temperature range inverse demulsifier according to claim 1, characterized in that: The modified block polyether is obtained by modifying the block polyether with allyltrimethylammonium chloride, and the block polyether is formed by block polymerization of propylene oxide and ethylene oxide.

4. The wide temperature range inverse demulsifier according to claim 1, characterized in that: The fatty alcohol polyoxyethylene ether mixture is composed of at least one low-carbon chain fatty alcohol polyoxyethylene ether with a carbon chain length of C8-10 and at least one high-carbon chain fatty alcohol polyoxyethylene ether with a carbon chain length of C12-16; The low-carbon chain fatty alcohol polyoxyethylene ethers include octanol polyoxyethylene 4 ether, octanol polyoxyethylene 6 ether and isooctyl alcohol polyoxyethylene ether; the high-carbon chain fatty alcohol polyoxyethylene ethers include lauryl alcohol polyoxyethylene 9 ether, lauryl alcohol polyoxyethylene 7 ether, lauryl alcohol polyoxyethylene 23 ether and hexadecyl alcohol polyoxyethylene ether with carbon chain lengths.

5. The wide temperature range inverse demulsifier according to claim 1, characterized in that: The phosphate surfactant is at least one of polysiloxane-modified phosphate, dihexadecyl phosphate, dioctyl phosphate, diisobutyl phosphate, didodecyl phosphate and sorbitol phosphate.

6. The wide temperature range inverse demulsifier according to claim 1, characterized in that: The mixed solvent is a mixed solvent of propylene glycol methyl ether and hexylene glycol, wherein the volume ratio of the propylene glycol methyl ether to the hexylene glycol is 1:1 to 3:

1.

7. A method for preparing a wide temperature range inverse demulsifier according to claims 1-6, characterized in that: The steps include: Step 1. At room temperature, adding a mixture of a modified block polyether, a phosphate surfactant and a fatty alcohol polyoxyethylene ether in a formula amount into a reaction kettle and stirring and mixing to obtain a mixed system; Step 2. Slowly heat the mixed system in step 1 to 40-60°C, add the mixed solvent in the formula amount, continue stirring for 10-20 minutes to obtain a uniform solution, and then cool to room temperature; Step 3. Add the modified galactomannan polysaccharide in the formula amount to the uniform solution of step 2, slowly raise the temperature to 35-45°C, and continue stirring for 10-30 minutes; Step 4. After the stirring is completed, add the formulated amount of nano zinc oxide and sodium silicate to the system in step 3, slowly heat to 60-70° C. and stir for 15-30 minutes to obtain the wide temperature range reverse demulsifier.

8. The method for preparing a wide temperature range inverse demulsifier according to claim 7, characterized in that: The preparation process of the modified galactomannan polysaccharide is as follows: (1) in a high pressure reactor, dispersing fennel gum in an isopropyl alcohol aqueous solution and a sodium hydroxide aqueous solution to obtain a dispersion; (2) adding propylene oxide and ethylene oxide to the dispersion obtained in step (1), reacting at a temperature of 70° C. and a pressure of 0.2 MPa for 3 h, and cooling to 50° C. after the reaction is completed; (3) adding an aqueous solution of trimethylammonium glycidyl chloride to the cooled system of step (2) and reacting at 50° C. for 3 h; (4) After the reaction is completed, the reaction mixture is neutralized with concentrated hydrochloric acid and diluted with isopropanol aqueous solution. After neutralization at room temperature for 1 hour, the reaction solution is poured into methanol, the reaction product is precipitated and filtered to separate, the obtained precipitate is washed with methanol aqueous solution, and the reaction product is dried under reduced pressure to obtain modified galactomannan polysaccharide.

9. The method for preparing a wide temperature range inverse demulsifier according to claim 7, characterized in that: The preparation process of the modified block polyether is as follows: First, propylene oxide and ethylene oxide are mixed, propylene glycol and NaOH are added, and block polymerization is carried out at a temperature of 100-120° C. and a pressure of 0.1-0.3 MPa for 8-12 hours to obtain a block polyether; Then, the block polyether is reacted with allyltrimethylammonium chloride at a temperature of 60-80° C. and a pressure of 0.1-0.3 MPa for 2-4 hours to obtain the modified block polyether; The mass ratio of the block polyether to allyltrimethylammonium chloride is 1:0.5 to 1:2, and the mass ratio of propylene oxide to ethylene oxide is 3:1 to 5:

1.

10. A method for using the wide temperature range inverse demulsifier according to any one of claims 1 to 6 or the inverse demulsifier prepared by the preparation method according to any one of claims 7 to 9, characterized in that: The wide temperature range reverse demulsifier is directly added to the pretreated oily wastewater, first stirred at high speed for 10-15 minutes, then stirred at low speed for 5-10 minutes, and finally allowed to stand for more than 30 minutes, so as to achieve rapid demulsification and oil-water separation of the oily wastewater; The addition amount is 50ppm-200ppm, the high-speed stirring speed is 100-300r / min, and the low-speed stirring speed is 30-60r / min.

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