High-stability phosphorus-free grey water dispersing agent and application thereof in coal gasification wastewater

Abstract

The invention relates to the technical field of dispersing agents, in particular to a high-stability phosphorus-free grey water dispersing agent and application thereof in coal gasification wastewater. The high-stability phosphorus-free grey water dispersing agent is prepared from the following raw material components in parts by mass (weight): 20 to 35 parts of polyepoxysuccinic acid (PESA), 5 to 15 parts of sulfonated carbon quantum dot modified polyaspartic acid, 10 to 15 parts of AA / AMPS / HPA terpolymer (acrylic acid / 2-acrylamide-2-methylpropanesulfonic acid / hydroxypropyl acrylate copolymer), 5 to 10 parts of quadripolymer, 8 to 15 parts of sodium gluconate, 1 to 3 parts of sodium hydroxide, 1 to 3 parts of sodium hydroxide, 1 to 3 parts of sodium hydroxide, 1 to 3 parts of sodium hydroxide, and the balance of water. 5 to 10 parts of hydroxypropyl methacrylate, 3 to 8 parts of glycerol and 10 to 20 parts of deionized water. The high-stability phosphorus-free grey water dispersing agent prepared by the invention has good scale inhibition performance and thermal stability, is free of phosphorus pollution and environment-friendly, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dispersants, and particularly relates to a high-stability phosphorus-free ash water dispersant and application thereof in coal gasification wastewater. BACKGROUND

[0002] In the coal gasification process, after coal reacts with a gasifying agent such as oxygen and water vapor, a large amount of solid particles such as fly ash, unreacted carbon, metal oxides and soluble impurities are generated. These substances enter the washing and cooling system with high-temperature synthesis gas, and finally most of them enter the ash water system. In addition to containing suspended solids, ash water also contains scale-forming ions such as calcium ions, magnesium ions, silicate ions, carbonate ions and sulfate ions.

[0003] When the ash water is used in the system, the temperature and pH value change, and these scale-forming ions combine to form hard scale layers, such as silicate scale, calcium carbonate scale and calcium sulfate scale.

[0004] Although the traditional phosphorus-containing dispersant has a certain scale inhibition effect, it has problems such as phosphorus pollution, poor biodegradability, insufficient stability under high temperature and high pressure, etc. The existing phosphorus-free dispersant is unstable under extreme conditions such as low temperature freezing and high temperature and high pressure, and it is difficult to meet the long-term operation requirements of the coal gasification wastewater system.

[0005] Therefore, it is of important industrial application value to develop an ash water dispersant with high-efficiency scale inhibition, environmental protection and resistance to extreme conditions. SUMMARY

[0006] The purpose of the present application is to provide a high-stability phosphorus-free ash water dispersant and its application in coal gasification wastewater, which is used to solve the above technical problems in the prior art.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: The technical scheme provided by the present application is as follows: In a first aspect, the present application provides a high-stability phosphorus-free ash water dispersant, which specifically comprises the following components by weight: polyepoxysuccinic acid (PESA) 20-35 parts, sulfonated carbon quantum dot modified polyaspartic acid 5-15 parts, AA / AMPS / HPA ternary copolymer (acrylic acid / 2-acrylamide-2-methylpropyl sulfonic acid / hydroxypropyl acrylate copolymer) 10-15 parts, quaternary copolymer 5-10 parts, sodium gluconate 8-15 parts, hydroxypropyl methacrylate 5-10 parts, glycerol 3-8 parts, and deionized water 10-20 parts.

[0008] Preferably, the preparation method of the sulfonated carbon quantum dot modified polyaspartic acid comprises the following steps: S1: 3,4-dihydroxyphenylalanine, o-phenylenediamine and p-aminobenzenesulfonic acid are dissolved in water, stirred and treated with concentrated sulfuric acid, then heated by microwave to obtain a gel, cooled to room temperature, impurities are removed and dried to obtain sulfonated carbon quantum dots; S2: poly succinimide, sulfonated carbon quantum dots and water are mixed, heated by water bath stirring, then the pH is adjusted with sodium hydroxide solution, the reaction is continued, the pH is adjusted to 7-8 with hydrochloric acid, impurities are removed and dried to obtain sulfonated carbon quantum dot modified polyaspartic acid.

[0009] In the above process, the amino group on the surface of the sulfonated carbon quantum dots attacks the carbonyl carbon in the cyclic imide structure of the poly succinimide, ring opening, forming an amide bond, covalently connecting the sulfonated carbon quantum dots to the main chain or side chain of the polymer. At the same time, the poly succinimide chain itself also undergoes partial hydrolysis and crosslinking to form a polyaspartic acid structure.

[0010] Preferably, in S1, the amount ratio of 3,4-dihydroxyphenylalanine, o-phenylenediamine, p-aminobenzenesulfonic acid, water and concentrated sulfuric acid is 10-20g:15-30g:5-10g:0.5-1L:4-8mL; the stirring and treatment time is 15-25min; the mass fraction of concentrated sulfuric acid is 95wt%; the microwave heating conditions are microwave heating power of 550-650W and microwave heating time of 6-10min; the impurity removal method is that the gel is washed with dichloromethane for 3-5 times, then 1-2L of ultrapure water is added, stirring is continued for 1.5-2.5h, then centrifugation is performed at a speed of 3300-3700rpm for 25-35min, the supernatant is taken and dialysis is performed with a molecular weight cutoff of 1000Da, then filtration is performed with a 0.22μm filter; the drying method is drying at 55-65℃ for 5-7h.

[0011] Preferably, in S2, the amount ratio of poly succinimide, sulfonated carbon quantum dots and water is 10-20g:1-2g:200-400mL; the water bath stirring and heating conditions are water bath stirring and heating temperature of 55-65℃ and water bath stirring and heating time of 0.5-1.5h; the mass fraction of sodium hydroxide solution is 10wt%; the continued reaction time is 12-14h; the concentration of hydrochloric acid is 1mol / L; the impurity removal method is dialysis with a molecular weight cutoff of 3500Da; the drying method is drying at 55-65℃ for 5-7h.

[0012] Preferably, the preparation method of the quaternary copolymer comprises the following steps: P1: carboxylated inulin is mixed with maleic anhydride, then N,N-dimethylformamide is added, stirring and treatment are performed, then reaction is performed to obtain modified inulin; P2: modified inulin, acrylic acid, AMPS, sodium p-styrenesulfonate and sodium hypophosphite are mixed, water and ammonium persulfate are added, then reaction is performed to obtain a quaternary copolymer.

[0013] In the above process, the quaternary copolymer is obtained by radical polymerization.

[0014] Preferably, in the P1, the amount ratio of carboxylated inulin, maleic anhydride, N,N-dimethylformamide is 76-152g:35-70g:0.5-1L; the stirring treatment time is 10-20min; the reaction conditions are: the reaction temperature is 85-95℃, and the reaction time is 8-12h.

[0015] Preferably, in the P2, the reaction conditions are: the reaction temperature is 65-75℃, and the reaction time is 1.5-2.5h; the amount ratio of modified inulin, acrylic acid, AMPS, sodium p-styrenesulfonate, sodium hypophosphite, water, ammonium persulfate is 33-66g:66-132g:33-66g:17-34g:11-22g:0.5-1L:3-6g.

[0016] Preferably, the preparation method of the carboxylated inulin comprises the following steps: A1: dissolving sodium periodate in water, then adding inulin solution and stirring to react in the dark, then terminating the reaction, removing impurities, and obtaining aldehyde inulin; A2: adding aldehyde inulin and sodium chlorite into a buffer system, reacting in the dark, then adding sodium hydroxide solution dropwise to adjust pH, removing impurities, and obtaining carboxylated inulin.

[0017] Preferably, in the A1, the preparation method of the inulin solution is: taking 200-400g inulin, dissolving it in 10-20L water to obtain an inulin solution; the amount ratio of sodium periodate to water is 120-240g:4-8L; the dark stirring reaction conditions are: the dark stirring reaction temperature is 25-35℃, and the dark stirring reaction time is 12-18h; the termination reaction method is: adding 80-160mL ethylene glycol to terminate the reaction; and the impurity removal method is: rotary evaporation after dialysis purification.

[0018] Preferably, in the A2, the amount ratio of aldehyde inulin, sodium chlorite, and buffer system is 100-200g:50-100g:2-4L; the buffer system is an acetic acid-sodium acetate buffer system with a pH of 4.5; the dark reaction conditions are: the dark reaction temperature is 30℃, and the dark reaction time is 12-18h; the concentration of the sodium hydroxide solution is 5mol / L; the pH value is 8; and the impurity removal method is: rotary evaporation after 45-50h dialysis purification.

[0019] Preferably, the preparation process of the high-stability phosphorus-free water dispersant comprises the following steps: Step (1) pre-mixed reaction: add deionized water in the reaction kettle, heat to 55℃, slowly add PESA, sulfonated carbon quantum dot modified polyaspartic acid, tetra-copolymer and sodium gluconate, stirring at 200-300 rpm for 25-35 min, so that it is fully dissolved and mixed; Step (2) gradient compounding: control the reaction system temperature at 58-62℃, adjust the pH to 6-7, slowly add the AA / AMPS / HPA terpolymer solution, the drop time is controlled at 1-2h, and the stirring speed is maintained at 250-350 rpm; Step (3) low temperature modification: reduce the system temperature to 38-42℃, add glycerol and hydroxypropyl methacrylate, and ultrasonic dispersion treatment for 10-20 min at a frequency of 40 kHz, to promote uniform distribution and interfacial compatibility of components; Step (4) curing treatment: the obtained product is placed at 25℃ for 45-51h for curing, a liquid product is obtained, filtered and packaged to obtain a high-stability non-phosphorus ash water dispersant.

[0020] Preferably, the application also provides the use of the high-stability non-phosphorus ash water dispersant in coal gasification wastewater.

[0021] In summary, due to the adoption of the above technical solutions, the application has the following advantages: 1. The high-stability non-phosphorus ash water dispersant prepared by the application uses polyepoxysuccinic acid (PESA) as the main body, which is easily biodegradable, and is compounded with sulfonated carbon quantum dot modified polyaspartic acid, AA / AMPS / HPA terpolymer and tetra-copolymer, completely abandoning phosphorus-containing components, avoiding water eutrophication, conforming to the development direction of green chemical industry, and improving the environmental friendliness of the product.

[0022] 2. The high-stability non-phosphorus ash water dispersant prepared by the application has high temperature and high pressure adaptability, with a scale inhibition rate still higher than 95% under the condition of 260℃ / 6.0MPa, and is suitable for high heat load systems such as coal gasification and thermal power; it also has low temperature stability, and the addition of glycerol effectively prevents freezing at low temperature, ensuring that there is no solidification phenomenon during transportation at-20℃, thereby widening the product application region and season.

[0023] 3.The high-stability non-phosphorus ash water dispersant prepared by the method has multi-scale dispersing capacity, the AA / AMPS / HPA ternary copolymer contains strong acid and weak acid groups on the molecular chain, is suitable for use under high-temperature, high-pH, high-hardness and high-alkali conditions, and the sulfonic acid groups in the quaternary copolymer can enhance the resistance to metal ions in high-salinity water, and the synergistically enhanced chemical stability and adaptability; the ternary copolymer has high calcium tolerance, can effectively inhibit the deposition of calcium carbonate, calcium phosphate, calcium sulfate, zinc scale and iron oxide in water, and has excellent dispersing performance; the nano sulfonated carbon quantum dot modified polyaspartic acid has a larger surface area, enhances ion chelation, and the sulfonic acid groups and amino groups in the sulfonated carbon quantum dots further improve chelation and electrostatic repulsion, and the synergistic effect of the sulfonic acid groups and amino groups on the surface of the carbon quantum dots strengthens the electrostatic repulsion and lattice distortion effect, and more effectively destroys the micro-forming process of scale; each oxidized fructose unit of the inulin in the quaternary copolymer can provide a calcium coordination bond, has stronger coordination capacity, and the modification makes it contain more functional groups, fully chelates with calcium ions, iron ions and the like, so that it is dissolved in water, reduces the generation of precipitated scale, and a large number of carboxylic acid groups in the quaternary copolymer enhance ion chelation in the solution; through the synergistic effect of the ternary copolymer, the nano sulfonated carbon quantum dot modified polyaspartic acid, the quaternary copolymer and sodium gluconate, efficient dispersion of various scales is realized, and the equipment cleaning cycle is prolonged.

[0024] 4.The high-stability non-phosphorus ash water dispersant prepared by the method can effectively prevent scale formation on the heat exchange surface, maintain high heat transfer efficiency of the system, and significantly reduce energy consumption; by preventing pipeline blockage and under-deposit corrosion, the system flowability is ensured, the service life of the equipment is prolonged, and unplanned shutdown is reduced, thereby bringing considerable economic benefits, and at the same time, the excellent dispersing performance improves the quality of ash water recycling, and water saving and emission reduction are realized. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 is a thermal decomposition rate curve of the high-stability non-phosphorus ash water dispersant of the present application. DETAILED DESCRIPTION

[0027] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application. Embodiment

[0028] The present embodiment discloses a preparation method of carboxylated inulin, comprising the following steps: A1: 180g sodium periodate is dissolved in 6L water, 300g inulin is dissolved in 15L water and mixed with the sodium periodate solution, stirred at 30℃ in the dark for 16h, 120mL ethylene glycol is added to terminate the reaction, after dialysis purification, rotary evaporation is performed to obtain aldehyde inulin; A2: 150g aldehyde inulin, 75g sodium chlorite are added to 3L, pH 4.5 acetic acid-sodium acetate buffer system, reacted at 30℃ in the dark for 15h, then 5mol / L sodium hydroxide solution is added dropwise until pH is 8, after 48h dialysis purification, rotary evaporation is performed to obtain carboxylated inulin. Embodiment

[0029] The present embodiment discloses a preparation method of a quaternary copolymer, comprising the following steps: P1: 114g carboxylated inulin prepared in embodiment 1 is mixed with 50g maleic anhydride, then 0.75L N,N-dimethylformamide is added and stirred for 15min, then reacted at 90℃ for 10h to obtain modified inulin; P2: 50g modified inulin, 99g acrylic acid, 50g AMPS, 25.5g sodium p-styrenesulfonate and 16.5g sodium hypophosphite are mixed, 0.75L water and 4.5g ammonium persulfate are added, and reacted at 70℃ for 2h to obtain a quaternary copolymer. Embodiment

[0030] The present embodiment discloses a preparation method of sulfonated carbon quantum dot modified polyaspartic acid, comprising the following steps: S1: 15g 3,4-dihydroxyphenylalanine, 22g o-phenylenediamine and 7.5g p-aminobenzenesulfonic acid are dissolved in 0.75L water, stirred for 20min, then 95wt%, 6mL concentrated sulfuric acid is added, and microwave heating is performed at 600W power for 8min to obtain a gel, the gel is washed with dichloromethane for 4 times, then 1.5L ultrapure water is added, and stirring is continued for 2h, then centrifugation is performed at 3500rpm for 30min, the supernatant is subjected to dialysis with a molecular weight cutoff of 1000Da, filtered with a 0.22μm filter membrane, and dried at 60℃ for 6h to obtain sulfonated carbon quantum dots; S2: 15 g of polysuccinimide, 1.5 g of sulfonated carbon quantum dots, and 300 mL of water were mixed, heated in a water bath at 60°C for 1 h, then the pH was adjusted to 10 with a 10 wt% sodium hydroxide solution, and the reaction was continued for 13 h. Then the pH was adjusted to 7.5 with 1 mol / L hydrochloric acid, dialysis was performed with a molecular weight cut-off of 3500 Da, and drying was performed at 60°C for 6 h to obtain sulfonated carbon quantum dot modified polyaspartic acid. Example

[0031] The present embodiment discloses a preparation process of a high-stability phosphorus-free ash water dispersant, comprising the following steps: Step (1) Pre-mixing reaction: 10 g of deionized water was added to the reaction kettle, heated to 55°C, and 35 g of PESA, 5 g of sulfonated carbon quantum dot modified polyaspartic acid prepared in Example 3, 10 g of tetrapolymer prepared in Example 2, and 8 g of sodium gluconate were slowly added. Stir at 300 rpm for 25 min to fully dissolve and mix; Step (2) Gradient compounding: control the reaction system temperature at 62°C, adjust the pH to 6, slowly add 15 g of AA / AMPS / HPA terpolymer solution, the dropwise time control in 1h, maintain the stirring speed 350rpm; Step (3) Low temperature modification: The system was cooled to 38°C, 8 g of glycerol and 5 g of hydroxypropyl methacrylate were added, and ultrasonic dispersion treatment was performed for 20 min at a frequency of 40 kHz to promote uniform distribution of components and interfacial compatibility. Step (4) Curing treatment: The obtained product was placed at 25°C for 48h for curing treatment, and a liquid product was obtained. Filtration and packaging were performed to obtain a high-stability phosphorus-free ash water dispersant. Example

[0032] The present embodiment discloses a preparation process of a high-stability phosphorus-free ash water dispersant, comprising the following steps: Step (1) Pre-mixing reaction: 10 g of deionized water was added to the reaction kettle, heated to 55°C, and 35 g of PESA, 5 g of sulfonated carbon quantum dot modified polyaspartic acid prepared in Example 3, 10 g of tetrapolymer prepared in Example 2, and 8 g of sodium gluconate were slowly added. Stir at 300 rpm for 25 min to fully dissolve and mix; Step (2) Gradient compounding: control the reaction system temperature at 62°C, adjust the pH to 6, slowly add 15 g of AA / AMPS / HPA terpolymer solution, the dropwise time control in 1h, maintain the stirring speed 350rpm; Step (3) Low temperature modification: The system was cooled to 38°C, 8 g of glycerol and 5 g of hydroxypropyl methacrylate were added, and ultrasonic dispersion treatment was performed for 20 min at a frequency of 40 kHz to promote uniform distribution of components and interfacial compatibility. Step (4) aging treatment: the product obtained was left to stand at 25°C for 45 h to obtain a liquid product, which was filtered and packaged to obtain the high-stability non-phosphorus ash water dispersant. Example

[0033] The present embodiment discloses a preparation process of a high-stability non-phosphorus ash water dispersant, comprising the following steps: Step (1) pre-mixing reaction: 20 g of deionized water was added to a reaction kettle, heated to 55°C, and 20 g of PESA, 15 g of sulfonated carbon quantum dot modified polyaspartic acid prepared in Example 3, 5 g of the quaternary copolymer prepared in Example 2 and 15 g of sodium gluconate were slowly added, and stirred at a speed of 200 rpm for 35 min to make them fully dissolved and mixed; Step (2) gradient compounding: the temperature of the reaction system was controlled at 58°C, the pH was adjusted to 7, 10 g of AA / AMPS / HPA ternary copolymer solution was slowly added, the dropping time was controlled at 2 h, and the stirring speed was maintained at 250 rpm; Step (3) low-temperature modification: the system was cooled to 42°C, 3 g of glycerol and 10 g of hydroxypropyl methacrylate were added, and ultrasonic dispersion treatment was carried out at a frequency of 40 kHz for 10 min to promote uniform distribution of components and interfacial compatibility; Step (4) aging treatment: the product obtained was left to stand at 25°C for 51 h to obtain a liquid product, which was filtered and packaged to obtain the high-stability non-phosphorus ash water dispersant.

[0034] Experimental data verification In order to verify the effect of the high-stability non-phosphorus ash water dispersant (number ND-XF2510) prepared in Example 4, two samples of ash water from Jiangsu Suo gasification device, one sample of ash water from Nanjing Chengzhi Clean Energy Co., Ltd. gasification device and one sample of dispersant (number CZ) from a certain factory were used for comparison test.

[0035] I. Comparison experiment of thermal decomposition rate (1) Experimental steps: 15 mg of ND-XF2510 dispersant and CZ dispersant were weighed and placed in the sample pan of the thermal gravimetric analyzer, and the sample pan was placed in the thermal gravimetric analyzer and ensured that the instrument was well sealed. Protective gas was introduced into the instrument to exclude air and prevent oxidation. The gas flow should be set according to the requirements of the instrument. The temperature was increased from room temperature to 700°C at a rate of 10°C / min. During the temperature rising process, the mass change and temperature data of the sample were continuously recorded.

[0036] (2) Data processing: According to the recorded data, the thermogravimetric curve (TG curve) is drawn, that is, the curve of mass change with temperature. From the TG curve, the temperature at which the sample begins to decompose (the initial decomposition temperature), the temperature at which the decomposition ends (the final decomposition temperature), and the temperature corresponding to the maximum decomposition rate (the peak temperature) are determined. The thermal decomposition rate, that is, the percentage of mass loss of the sample in the experimental temperature range, is calculated. The calculation formula of the thermal decomposition rate is: thermal decomposition rate = (initial mass - final mass) / initial mass x 100%.

[0037] (3) Experimental data results: According to the data recorded during the comparison experiment of the two dispersant samples, the thermogravimetric curve (TG curve) is drawn as shown in Figure 1

[0038] ND-XZ2510 dispersant explanation: (1) At a temperature of about 110°C, the weight loss is 37.68%, and the remaining is 62.32%. At this time, all the loss is water, and part of the crystal water has not been completely evaporated.

[0039] (2) At a temperature of about 230°C, the weight loss is 20.97% from 110°C to 230°C, and the remaining is 41.35%. The solid content of the dispersant at this time is 42%, so it can be known that the product is basically not decomposed from 0 to 230°C.

[0040] (3) At a temperature of about 310°C, the weight loss is 12.93% from 230°C to 310°C, and the remaining is 28.42%. The undecomposed rate of the product at this stage is 67.93%.

[0041] (4) At a temperature of about 410°C, the weight loss is 16.79% from 310°C to 410°C, and the remaining is 11.63%. The undecomposed rate of the product at this stage is 27.80%.

[0042] (5) At a temperature of about 500°C, the weight loss is 3.44% from 410°C to 500°C, and the remaining is 8.19%. The undecomposed rate of the product at this stage is 19.57%.

[0043] (6) At a temperature of about 600°C, the weight loss is 4.23% from 500°C to 600°C, and the remaining is 3.96%. The undecomposed rate of the product at this stage is 9.46%.

[0044] (7) At a temperature of about 680°C, the weight loss is 3.69% from 600°C to 680°C, and the remaining is 0.27%. The undecomposed rate of the product at this stage is 0.65%, and the product is basically decomposed at this temperature.

[0045] CZ dispersant explanation: ​(1) When the temperature is about 110℃, the weight loss is 40.76%, and the remaining is 59.24%. At this time, all the loss is water, and part of the crystal water has not been evaporated.

[0046] (2) When the temperature is about 250℃, the weight loss is 33.11% from 110℃ to 250℃, and the remaining is 26.13%. The solid content of the dispersant is 26% at this time. Therefore, it can be known that the product is basically not decomposed from 0 to 230℃.

[0047] (3) When the temperature is about 310℃, the weight loss is 14.41% from 250℃ to 310℃, and the remaining is 11.72%. The undecomposed rate of the product at this stage is 45.96%.

[0048] (4) When the temperature is about 410℃, the weight loss is 2.27% from 310℃ to 410℃, and the remaining is 9.45%. The undecomposed rate of the product at this stage is 37.06%.

[0049] (5) When the temperature is about 500℃, the weight loss is 2.63% from 410℃ to 500℃, and the remaining is 6.82%. The undecomposed rate of the product at this stage is 26.75%.

[0050] (6) When the temperature is about 600℃, the weight loss is 3.25% from 500℃ to 600℃, and the remaining is 3.57%. The undecomposed rate of the product at this stage is 14.0%.

[0051] (7) When the temperature is about 680℃, the weight loss is 3.44% from 600℃ to 680℃, and the remaining is 0.13%. The undecomposed rate of the product at this stage is 0.51%. At this temperature, the product is basically decomposed.

[0052] Therefore, it can be known that the undecomposed rate of the ND-XF2510 dispersant involved in the present application is higher than that of the CZ dispersant at the same temperature, which indicates that the dispersant of the present application has high high-temperature thermal decomposition resistance.

[0053] II. Static scale inhibition rate test of calcium carbonate scale with different addition rates in the same water quality The water quality used: two gray water samples from the gasification device of Jiangsu Suopo Methanol Factory, with addition rates of 60ppm and 100ppm respectively. The dispersant: ND-XF2510 dispersant prepared in Example 4 of the present application.

[0054] (1) Experimental principle: based on the existence of calcium carbonate dissolution-precipitation balance in aqueous solution. Add scale inhibitor to hard water with high concentration. The scale inhibitor inhibits the precipitation of calcium carbonate by chelation, dispersion or lattice distortion. The remaining Ca 2+ concentration in the solution before and after the treatment of water agent is measured to calculate the scale inhibition rate.

[0055] (2) Experimental method: The test solution is prepared with actual working water or prepared water containing a certain amount of bicarbonate and calcium ions and dispersant. Under heating conditions, the decomposition of calcium bicarbonate into calcium carbonate is accelerated. After reaching equilibrium, the calcium ion concentration in the test solution is measured. The greater the calcium ion concentration, the better the scale inhibition performance of the dispersant.

[0056] (3) Experimental steps: The test solution and the blank test solution are respectively placed in two clean conical flasks and immersed in a constant temperature water bath at (80±1) ℃ (the page of the test solution should not be higher than the liquid level of the water bath), and then constant temperature is placed for 10 h. Dry filter with medium speed quantitative filter paper while hot. After the filtrate is cooled, 25.00 mL of the filtrate is transferred to a 250 mL conical flask, water is added to 80 mL, 5 mL of potassium hydroxide solution and about 0.1 g of calcium-carboxylic acid indicator are added. Titrate with ethylenediaminetetraacetic acid disodium standard solution until the solution changes from purple red to bright blue, which is the end point. The mass concentration of calcium ions in the test solution and the blank test solution is calculated respectively. The test results are shown in Table 1: Table 1

[0057] From Table 1, it can be seen that: (1) The relative scale inhibition rate of the 1# water sample is 86.69% under the condition that the dispersant addition rate is 60 ppm.

[0058] (2) The relative scale inhibition rate of the 1# water sample is 96.42% under the condition that the dispersant addition rate is 100 ppm.

[0059] (3) The relative scale inhibition rate of the 2# water sample is 89.94% under the condition that the dispersant addition rate is 60 ppm.

[0060] (4) The relative scale inhibition rate of the 2# water sample is 99.25% under the condition that the dispersant addition rate is 100 ppm.

[0061] (5) Under the same conditions, the higher the dispersant addition rate, the greater the calcium ion concentration, and the better the scale inhibition performance of the dispersant.

[0062] III. Comparison of scale inhibition effects of ND-XF2510 dispersant and CZ dispersant Experimental water quality: ash water of Nanjing Chengzhi Clean Energy Co., Ltd. gasification device Dispersant: ND-XF2510 dispersant, CZ dispersant The experimental process is as described above, and the test data is shown in Table 2: Table 2

[0063] From Table 2, it can be seen that the scale inhibition effect of the ND-XF2510 dispersant involved in the present application is obviously better than that of the CZ dispersant used on site.

[0064] The above merely provides the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any modification or change made by those skilled in the art within the technical scope disclosed by the present application and the inventive concept thereof should be covered within the protection scope of the present application.

[0065] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details and limit the present application to the specific embodiments. Obviously, many modifications and variations can be made in light of the above teachings. The above description is selected and described for the best illustrating the principles of the present application and the practical application, so that those skilled in the art can well understand and utilize the present application. The present application is only limited by the claims and their full scope and equivalents.

Claims

1. A high stability non-phosphorus scale water dispersant, characterized by, The raw material of the high-stability phosphorus-free ash water dispersant is composed of the following components in mass (weight) parts: PESA 20-35 parts, sulfonated carbon quantum dot modified polyaspartic acid 5-15 parts, AA / AMPS / HPA terpolymer 10-15 parts, quaternary copolymer 5-10 parts, sodium gluconate 8-15 parts, hydroxypropyl methacrylate 5-10 parts, glycerol 3-8 parts, and deionized water 10-20 parts.

2. The high stability non-phosphorus ash water dispersant according to claim 1, characterized by, The preparation method of the sulfonated carbon quantum dot modified polyaspartic acid comprises the following steps: S1: 3,4-dihydroxyphenylalanine, o-phenylenediamine and p-aminobenzenesulfonic acid are dissolved in water, stirred and treated, then concentrated sulfuric acid is added, and then gel is obtained by microwave heating, and after cooling to room temperature, impurities are removed and dried to obtain sulfonated carbon quantum dots; S2: poly succinimide, sulfonated carbon quantum dots and water are mixed, heated by water bath stirring, then the pH is adjusted by sodium hydroxide solution, the reaction is continued, then the pH value is adjusted to 7-8 by hydrochloric acid, impurities are removed, and dried to obtain sulfonated carbon quantum dot modified polyaspartic acid.

3. The high stability non-phosphorus ash water dispersant according to claim 2, characterized by, In S1, the amount ratio of 3,4-dihydroxyphenylalanine, o-phenylenediamine, p-aminobenzenesulfonic acid, water and concentrated sulfuric acid is 10-20 g:15-30 g:5-10 g:0.5-1 L:4-8 mL; the stirring and treatment time is 15-25 min; the mass fraction of concentrated sulfuric acid is 95 wt%; the microwave heating conditions are microwave heating power of 550-650 W and microwave heating time of 6-10 min; the impurity removal method is that the gel is washed with dichloromethane for 3-5 times, then 1-2 L of ultrapure water is added, stirring is continued for 1.5-2.5 h, then centrifugation is performed at a speed of 3300-3700 rpm for 25-35 min, the supernatant is taken and dialyzed with a molecular weight cutoff of 1000 Da, and filtered with a 0.22 μm filter; and the drying method is drying at 55-65℃ for 5-7 h.

4. The high stability non-phosphorus ash water dispersant according to claim 2, characterized by, In S2, the amount ratio of poly succinimide, sulfonated carbon quantum dots and water is 10-20 g:1-2 g:200-400 mL; the water bath stirring and heating conditions are water bath stirring and heating temperature of 55-65℃ and water bath stirring and heating time of 0.5-1.5 h; the mass fraction of sodium hydroxide solution is 10 wt%; the continued reaction time is 12-14 h; the concentration of hydrochloric acid is 1 mol / L; the impurity removal method is dialysis with a molecular weight cutoff of 3500 Da; and the drying method is drying at 55-65℃ for 5-7 h.

5. The high stability non-phosphorus ash water dispersant according to claim 1, characterized by, The preparation method of the quaternary copolymer comprises the following steps: P1: carboxylated inulin is mixed with maleic anhydride, then N,N-dimethylformamide is added, stirring and treatment are performed, and then reaction is performed to obtain modified inulin; P2: modified inulin, acrylic acid, AMPS, sodium p-styrenesulfonate and sodium hypophosphite are mixed, water and ammonium persulfate are added, and then reaction is performed to obtain a quaternary copolymer.

6. The high stability non-phosphorus ash water dispersant according to claim 5, characterized by, The P1, the amount ratio of carboxylated inulin, maleic anhydride, N,N-dimethylformamide is 76-152g:35-70g:0.5-1L; the stirring treatment time is 10-20min; the reaction condition: the reaction temperature is 85-95℃, the reaction time is 8-12h; in the P2, the reaction condition: the reaction temperature is 65-75℃, the reaction time is 1.5-2.5h; the amount ratio of modified inulin, acrylic acid, AMPS, sodium p-styrene sulfonate, sodium hypophosphite, water, ammonium persulfate is 33-66g:66-132g:33-66g:17-34g:11-22g:0.5-1L:3-6g.

7. The high stability non-phosphorus ash water dispersant according to claim 5, characterized by, The preparation method of the carboxylated inulin comprises the following steps: A1: dissolve sodium periodate in water, then add inulin solution and stir to react in the dark, then terminate the reaction, remove impurities, and obtain aldehyde inulin; A2: add aldehyde inulin and sodium chlorite into a buffer system, react in the dark, then add sodium hydroxide solution dropwise to adjust pH, remove impurities, and obtain carboxylated inulin.

8. The high stability non-phosphorus ash water dispersant according to claim 7, characterized by, In the A1, the preparation method of the inulin solution is as follows: 200-400g inulin is dissolved in 10-20L water to obtain an inulin solution; the amount ratio of sodium periodate to water is 120-240g:4-8L; the light-shielded stirring reaction condition is that the light-shielded stirring reaction temperature is 25-35℃ and the light-shielded stirring reaction time is 12-18h; the termination reaction method is to add 80-160mL ethylene glycol to terminate the reaction; and the impurity removal method is to perform dialysis purification and then rotary evaporation; in the A2, the amount ratio of aldehyde inulin, sodium chlorite and buffer system is 100-200g:50-100g:2-4L; the buffer system is an acetic acid-sodium acetate buffer system with a pH of 4.5; the light-shielded reaction condition is that the light-shielded reaction temperature is 30℃ and the light-shielded reaction time is 12-18h; the concentration of the sodium hydroxide solution is 5mol / L; the pH value is 8; and the impurity removal method is to perform dialysis purification for 45-50h and then rotary evaporation.

9. The high stability non-phosphorus ash water dispersant according to claim 1, characterized by, The preparation process of the high-stability phosphorus-free ash water dispersant comprises the following steps: Step (1) pre-mixing reaction: deionized water is added into a reaction kettle, heated to 55℃, and PESA, sulfonated carbon quantum dot modified polyaspartic acid, a quaternary copolymer and sodium gluconate are slowly added, and stirred at a speed of 200-300rpm for 25-35min to make them fully dissolved and mixed; Step (2) gradient compounding: the temperature of the reaction system is controlled at 58-62℃, the pH is adjusted to 6-7, and the AA / AMPS / HPA ternary copolymer solution is slowly added dropwise, the dropwise adding time is controlled at 1-2h, and the stirring speed is maintained at 250-350rpm; Step (3) low-temperature modification: the system is cooled to 38-42℃, and glycerol and hydroxypropyl methacrylate are added, and ultrasonic dispersion treatment is carried out at a frequency of 40kHz for 10-20min to promote the uniform distribution of components and interfacial compatibility; Step (4) curing treatment: the obtained product is placed at 25℃ for curing for 45-51h to obtain a liquid product, which is filtered and packaged to obtain the high-stability phosphorus-free ash water dispersant.

10. Use of the high-stability non-phosphorus ash water dispersant according to claim 9 in coal gasification wastewater.

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