Aircraft deicing fluid and method of making

Abstract

The application discloses thickening deicing and anti-icing liquid for type IV aircraft and a manufacturing method thereof. The manufacturing process comprises the following steps: preparing a pre-thickening concentrated thickening agent (flowable concentrated liquid) by pre-swelling and pre-dispersing a thickening polymer in an alcohol-water mixed medium; then mixing the pre-thickening concentrated thickening agent with alcohol-water base liquid through a pipeline online mixing device, and then performing high-speed shearing homogenization treatment through a high-speed dispersion device to obtain the type IV aircraft deicing and anti-icing liquid. Through the innovative process combination of "pre-thickening concentration first and then online high-speed homogenization", the traditional kettle type low-speed stirring batch production process is replaced, the "fish eye" problem caused by direct powder feeding of the thickening agent is effectively eliminated, the production cycle can be shortened, the viscosity stability and uniformity between batches of products can be improved, the process flow is simple, the equipment investment is small, and the process is suitable for continuous and large-scale production.

Description

Technical Field

[0001] This invention application relates to the field of aircraft ground de-icing and anti-icing technology, specifically to a thickened de-icing and anti-icing fluid for Type IV aircraft and its manufacturing method. Background Technology

[0002] Aircraft face safety challenges due to icing during winter operations. Ice and snow accumulation on surfaces such as wings and engine intakes not only increases aircraft weight but also disrupts aerodynamics, directly impacting flight safety. Currently, the civil aviation industry commonly uses ground-based spraying of de-icing and anti-icing fluids for de-icing and to create a protective barrier. According to SAE AMS 1424 and SAE AMS 1428 standards, aircraft de-icing and anti-icing fluids are classified into four types: Type I, Type II, Type III, and Type IV. Type I is a Newtonian fluid with low viscosity, primarily used for heating de-icing, but its anti-icing retention time is short. Types II, III, and IV are non-Newtonian pseudoplastic fluids containing thickening components, with higher viscosity, forming a durable protective film on aircraft surfaces, effectively extending the anti-icing retention time. Type IV fluid is specifically designed for aircraft with low aerodynamic performance requirements, possessing the highest viscosity and the longest anti-icing retention time, suitable for aircraft with low takeoff speeds.

[0003] Currently, the manufacturing processes for de-icing and anti-icing fluids (including Type IV) for non-Newtonian aircraft mainly employ the following technical routes: (1) Stirred tank process for direct online addition of thickener The traditional method involves directly adding a solid powdered polymer thickener to a mixture of freezing point depressants such as ethylene glycol / propylene glycol and deionized water. This thickening process is achieved by dissolving, swelling, and dispersing the thickener in a large stirred tank at low speed. Commonly used thickeners include water-soluble polymers such as polyacrylic acid and its derivatives, xanthan gum, and guar gum. The international aviation industry widely uses this alcohol / water mixture thickened with a water-soluble polymer to prepare non-Newtonian de-icing and anti-icing fluids.

[0004] The existing batch stirring process has the following obvious shortcomings: First, thickeners have a long dissolution and dispersion cycle. Polymer thickeners, especially high molecular weight polymers, require a long time to fully swell and disperse evenly in alcohol-water mixtures. Producing a batch of finished products usually takes several hours or even longer, which severely restricts production efficiency.

[0005] Secondly, it is prone to agglomeration and "fish-eye" problems. When solid powder thickeners are directly added to liquids, the outer layer quickly absorbs water to form a gel film, which prevents the internal powder from being further wetted. This results in a large number of incompletely dissolved microgel particles, causing excessively high local viscosity, poor stability and uniformity in the product, making it difficult to ensure viscosity consistency between different batches.

[0006] Third, it is highly dependent on large-capacity mixing equipment. This process relies on the mixing capacity of large mixing tanks and low-speed mixing equipment, which requires a large investment in equipment and a large floor space. Furthermore, it requires strict control of parameters such as feeding speed and mixing time during operation.

[0007] (2) The scheme of using surfactants to replace polymer thickeners To address the issue of polymer residues potentially reabsorbing water and forming hydrated gels during high-altitude aircraft flight, some researchers have opted to use nonionic surfactants (such as alkylolamine surfactants) instead of polymers as thickening components, constructing the system viscosity through micelle self-assembly at a certain concentration. While this approach reduces the risk of hydrated gels to some extent, systems thickened with surfactants have relatively limited tolerance to temperature changes and monovalent / divalent salt ions. The critical micelle concentration of the surfactant is sensitive to changes in solution conditions (concentration, ionic strength, etc.), resulting in less reliable viscosity stability during storage, transportation, and dilution compared to traditional polymer-thickened systems. Furthermore, surfactants themselves lack the chain entanglement ability and spatial network structure comparable to polymers, limiting their ability to achieve the rheological properties required for long anti-icing retention times. Additionally, this approach remains a batch process, failing to address the efficiency issues in the production process.

[0008] (3) Direct preparation of concentrated solution US Patent 5,863,973 discloses a "universal" aircraft de-icing and anti-icing fluid based on associative polymers, which mentions that the fluid can be prepared as a concentrate and then diluted at the point of use. The neutralization and thickening processes, as well as the rheological construction process, are all carried out in a batch reactor, without fundamentally simplifying the process. Furthermore, it focuses primarily on formulation innovation rather than systematic improvements to the manufacturing process, and does not provide a clear solution to the adaptability issues of large-scale continuous production.

[0009] Based on the above analysis, the existing technology for manufacturing de-icing and anti-icing fluids for Type IV aircraft has the following main shortcomings: First, the thickening process mainly relies on traditional batch production in kettles, which has low mixing efficiency and a long cycle for the entire production process (feeding, dispersion, swelling, homogenization), making it unsuitable for large-scale continuous and efficient production. Secondly, the direct addition of solid thickener powder causes the "fish eye" problem, resulting in incompletely dissolved microgel particles in the system, which leads to insufficient viscosity stability between product batches. Local pregel patches caused by the equipment stirring dead zone will further aggravate the unevenness of product quality. Third, the existing process relies on large-scale, low-speed mixing equipment, which increases equipment investment and energy consumption, and the process route is not simplified enough. Summary of the Invention

[0010] This invention aims to solve the technical problems of low production efficiency, poor product stability, and complex process flow in the existing manufacturing process of de-icing and anti-icing fluid for Type IV aircraft. Specifically, it addresses key challenges such as efficient and uniform dispersion of thickeners in alcohol-water systems, shortening production cycles, improving batch stability, and simplifying process flow. The first aspect of this invention provides...

[0011] A method for manufacturing a de-icing and anti-icing fluid for a Type IV aircraft includes the following steps: (1) The thickening polymer is added to an alcohol-water mixture and pre-swelled at 10-40°C for 2-12 hours. The mixture is then stirred at 50-200 rpm to disperse the thickening polymer. Deionized water is then added to make the mass percentage of the thickening polymer 2%-15%, thus obtaining a pre-thickened concentrated thickener that can be transported by a metering pump. The volume ratio of alcohol to water in the alcohol-water mixture is 1:0.5-1:2. (2) Mix the freezing point depressant with deionized water to obtain an alcohol-water base solution; (3) The pre-thickening concentrated thickener and the alcohol-water base liquid are transported separately by independent metering pumps, and the two are continuously fed into the pipeline online mixing device at a volume flow ratio of 1:5 to 1:50. They are initially mixed in the pipeline under the flow state to obtain a preliminary mixture. (4) The preliminary mixture is continuously transported in a pipeline to an online high-speed dispersion device with a rotor-stator homogenizing working head, and sheared and homogenized at a rotor speed of 5,000 to 30,000 rpm to obtain the Type IV aircraft de-icing and anti-icing fluid.

[0012] Furthermore, the thickening polymer is selected from at least one of polyacrylic acid, cross-linked polyacrylic acid copolymer, xanthan gum, guar gum, carboxymethyl cellulose, and hydroxyethyl cellulose.

[0013] Furthermore, the thickening polymer is a cross-linked polyacrylic acid polymer; the mass percentage of the thickening polymer in the pre-thickening concentrated thickener is 3% to 8%; and the volume ratio of alcohol to water in the alcohol-water mixture is 1:1.

[0014] Furthermore, the freezing point depressant and the alcohol in the alcohol-water mixture are each independently selected from at least one of ethylene glycol, propylene glycol, and diethylene glycol; the mass percentage of alcohols in the alcohol-water base solution is 30% to 70%.

[0015] Furthermore, in step (3), the volume flow ratio of the pre-thickened concentrated thickener to the alcohol-water base liquid is 1:10 to 1:20.

[0016] Furthermore, the pipeline online mixing device is equipped with at least one of a static mixing element and a spiral mixing unit.

[0017] Furthermore, after step (4), the apparent viscosity and freezing point of the obtained Type IV aircraft de-icing and anti-icing fluid are detected online, and the Type IV aircraft de-icing and anti-icing fluid with a freezing point not higher than -30°C is dispensed.

[0018] According to a second aspect of this application, a type IV aircraft de-icing and anti-icing fluid manufactured by the above-described manufacturing method is provided. It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of this application.

[0019] Beneficial technical effects of the present invention: (1) Significantly improved product quality. The pre-swelling-pre-dispersion treatment of polymers in pre-thickened and concentrated thickeners effectively eliminates the "fish-eye" problem caused by direct feeding. Combined with high-speed shear homogenization treatment, the distribution of active polymer network in alcohol-water base liquid is more uniform, the polymer chains are fully extended and highly homogenized, the viscosity stability of the product is high, the viscosity changes little after long-term storage, and the product performance consistency between batches is good.

[0020] (2) Simplified process flow and shortened production cycle per batch. Traditional process requires multiple time-consuming stages from feeding to discharging, such as powder swelling, crushing and homogenizing of the swollen body, and rheological aging equilibrium of the system, which usually takes several hours or even longer. This invention eliminates or greatly reduces the time-consuming steps of powder swelling-slow stirring-system equilibrium. Online mixing and high-speed dispersion in pipelines complete the homogenization process in a short time, and the production cycle of the whole process is significantly shortened compared with the traditional process.

[0021] (3) Reduced equipment investment and operating costs. This invention does not rely on large mixing tanks for slow mixing. The main equipment consists of pipeline mixing devices and online high-speed dispersion devices. The equipment is small in size, consumes little energy, occupies little space, and has low maintenance costs.

[0022] (4) Strong process scalability. The continuous process mode of online mixing and high-speed dispersion in pipelines can easily expand the production capacity by connecting multiple sets of pipelines in parallel. It has good industrial scalability and is suitable for large-scale continuous production.

[0023] (5) The product conforms to international standards. The Type IV aircraft de-icing and anti-icing fluid prepared by this invention meets the technical requirements of SAE AMS 1428 standard and GB / T 20857-2012, and its key properties such as freezing point, viscosity, and anti-icing retention time all meet the standards.

[0024] (6) Strong process adaptability. By adjusting the formulation of the pre-thickening concentrated thickener (type and concentration of thickening polymer) and the online mixing flow ratio, the thickening degree and other performance indicators of the final product can be flexibly adjusted to meet the production needs of different levels of products such as Type II, Type III and even Type IV. Attached Figure Description

[0025] Figure 1 The overall flow chart of the manufacturing process of the de-icing and anti-icing fluid for aircraft type IV of this invention.

[0026] Figure 2 : Schematic diagram of the preparation process of the pre-thickening and concentrated thickener of the present invention.

[0027] Figure 3 These are comparative photographs of the appearance of aircraft de-icing fluid samples prepared in Example 1 and Comparative Examples 1 to 6 of the present invention. The samples in the figures are, from left to right, Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3, Comparative Example 4, Comparative Example 5 and Comparative Example 6. Detailed Implementation

[0028] The alternative embodiments of this application will now be described in more detail with reference to the accompanying drawings. While alternative embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0029] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0030] The present invention will now be described in detail with reference to the accompanying drawings, as follows: A method for manufacturing a de-icing and anti-icing fluid for a Type IV aircraft includes the following steps: (1) The thickening polymer is added to an alcohol-water mixture and pre-swelled at 10-40°C for 2-12 hours. The mixture is then stirred at 50-200 rpm to disperse the thickening polymer. Deionized water is then added to make the mass percentage of the thickening polymer 2%-15%, thus obtaining a pre-thickened concentrated thickener that can be transported by a metering pump. The volume ratio of alcohol to water in the alcohol-water mixture is 1:0.5-1:2. By pre-swelling and pre-dispersion treatment, the thickening polymer is transformed from a solid powder state into a fluid and pumpable concentrated liquid state, thereby reducing agglomeration, microgel particles, and "fisheye" phenomena that occur when solid powder is directly fed. The pre-thickening concentrated thickener can be prepared independently in advance and stored for later use to reduce the swelling waiting time in the main production line.

[0031] (2) Mix the freezing point depressant with deionized water to obtain an alcohol-water base solution; The alcohol-water base solution is used to provide the required freezing point reduction properties for the product and serves as a dilution medium for the pre-thickened concentrated thickener. Pre-mixing the freezing point lowering agent with deionized water helps reduce compositional fluctuations during subsequent online mixing.

[0032] (3) The pre-thickening concentrated thickener and the alcohol-water base liquid are transported separately by independent metering pumps, and the two are continuously fed into the pipeline online mixing device at a volume flow ratio of 1:5 to 1:50. They are initially mixed in the pipeline under the flow state to obtain a preliminary mixture. Using independent metering pumps, the flow rates of the two materials can be controlled separately, and their proportions can be continuously adjusted. After the two materials enter the online mixing device, they undergo preliminary dispersion under the action of flow shear, diversion, and convection, so that the high-viscosity pre-thickening concentrated thickener is initially and evenly distributed in the alcohol-water base liquid.

[0033] (4) The preliminary mixture is continuously transported in a pipeline to an online high-speed dispersion device with a rotor-stator homogenizing working head, and sheared and homogenized at a rotor speed of 5,000 to 30,000 rpm to obtain the Type IV aircraft de-icing and anti-icing fluid.

[0034] The rotor-stator homogenizing head further refines the locally high-viscosity fluid units in the initial mixture through shearing, turbulence, and fluid impact, and ensures that the thickening polymer is uniformly distributed in the alcohol-water system. The initial mixing in the pipeline and the high-speed shear homogenization form a continuous two-stage mixing process, which is beneficial for balancing dispersion efficiency, polymer network integrity, and product uniformity.

[0035] In one embodiment of this invention, the thickening polymer is selected from at least one of polyacrylic acid, cross-linked polyacrylic acid copolymer, xanthan gum, guar gum, carboxymethyl cellulose, and hydroxyethyl cellulose.

[0036] The aforementioned thickening polymers can swell, hydrate, or entangle in aqueous or alcohol-water media, thereby increasing the low-shear viscosity of the system. Different thickening polymers can be used alone or in combination to adjust the viscosity, shear thinning degree, and storage stability of the product.

[0037] In one embodiment of this invention, the thickening polymer is a cross-linked polyacrylic acid polymer; the mass percentage of the thickening polymer in the pre-thickening concentrated thickener is 3% to 8%; and the volume ratio of alcohol to water in the alcohol-water mixture is 1:1.

[0038] Crosslinked polyacrylic acid polymers can form polymer networks with high low-shear viscosity and significant shear-thinning properties. Maintaining their concentration at 3%–8% achieves a balance between concentration and pumpability; a 1:1 volume ratio of alcohol to water is beneficial for both polymer wetting and hydration swelling.

[0039] In one embodiment of this invention, the freezing point depressant and the alcohol in the alcohol-water mixture are each independently selected from at least one of ethylene glycol, propylene glycol, and diethylene glycol; the mass percentage of alcohols in the alcohol-water base solution is 30% to 70%.

[0040] Ethylene glycol, propylene glycol, and diethylene glycol can all form homogeneous systems with water and lower the freezing point of the solution. The alcohol content can be adjusted according to the target freezing point, ambient temperature, and product rheological properties to balance the freezing point lowering ability with the hydration state of the thickening polymer.

[0041] In one embodiment of this invention application, the volume flow ratio of the pre-thickening and concentrated thickener to the alcohol-water base liquid in step (3) is 1:10 to 1:20.

[0042] This flow ratio facilitates sufficient dilution and initial dispersion of the pre-thickening concentrated thickener within the pipeline and is suitable for use in conjunction with pre-thickening concentrated thickeners containing 3%–8% by mass of thickening polymer. The viscosity of the final product can be controlled during production by adjusting the flow rate of the metering pump.

[0043] In one embodiment of this invention, the pipeline online mixing device is provided with at least one of a static mixing element and a spiral mixing unit.

[0044] Static mixing elements and spiral mixing units enable fluids to be repeatedly split, redirected, and recombine within the pipeline, increasing the contact area and radial exchange between the two materials. The mixing elements can be installed individually or in combination to improve initial mixing uniformity.

[0045] In one embodiment of this invention application, after step (4), the apparent viscosity and freezing point of the obtained Type IV aircraft de-icing and anti-icing fluid are detected online, and the Type IV aircraft de-icing and anti-icing fluid with a freezing point not higher than -30°C is dispensed.

[0046] Apparent viscosity testing should be conducted under uniform temperature, rotor type, and speed conditions to evaluate the product's rheological properties and batch consistency. Through online or near-line testing, the delivery ratio of the two materials or the composition of the alcohol-water base solution can be adjusted based on the test results, and the product can be repackaged after meeting requirements.

[0047] In one embodiment of this invention application, a Type IV aircraft de-icing and anti-icing fluid manufactured by the above-described manufacturing method is provided.

[0048] The thickening polymer in the Type IV aircraft de-icing and anti-icing fluid is introduced in the form of a pre-thickened concentrated thickener and uniformly distributed in the alcohol-water system through preliminary online mixing and high-speed shear homogenization. The resulting product exhibits non-Newtonian pseudoplastic rheological properties, forming a relatively stable protective liquid film under low shear conditions. Its apparent viscosity decreases under spraying, pumping, or takeoff shearing, which is beneficial for product spraying and liquid film shearing.

[0049] For clarity, the following examples will be used to provide a detailed description.

[0050] I. General Equipment, Raw Materials and Testing Methods (a) General equipment Unless otherwise specified, each embodiment employs two independent volumetric metering pumps. The in-line mixing device is a DN32 in-line static mixer with a built-in helical static mixing element; its outlet is connected to the inlet of the in-line high-speed dispersion device via a DN32 connecting pipe of 0.8 m in length. The in-line high-speed dispersion device uses a rotor-stator homogenizing head with a rotor outer diameter of 40 mm, a radial clearance of 0.4 mm between the rotor and stator, and a rated power of 7.5 kW. All samples are homogenized using a single-pass shearing method, without intermediate storage tanks or secondary mixing in a batch reactor.

[0051] (II) General preparation method of alcohol-water base solution To every 1000 kg of alcohol-water base solution, add the specified amounts of ethylene glycol, propylene glycol, and / or diethylene glycol, along with 0.30 kg of disodium ethylenediaminetetraacetate, 1.00 kg of sodium benzoate, 1.50 kg of C12–C14 fatty alcohol polyoxyethylene (7) ether, 0.10 kg of silicone defoamer, and 0.02 kg of water-soluble green dye, and then bring the total volume to 1000 kg with deionized water. Stir at 100 r / min for 20 min at 23±2℃ to obtain a homogeneous alcohol-water base solution.

[0052] (III) Standardized testing methods 1. Density: The density was measured using a vibratory densitometer at 20.0±0.2℃, with each sample measured in triplicate.

[0053] 2. Apparent viscosity: A Brookfield DV2T rotational viscometer or equivalent instrument was used with an LV-2 rotor; the sample was equilibrated at 20.0±0.2℃ for 60 min. New parallel samples were used at 0.3 r / min, 6 r / min and 30 r / min, and the values ​​were read after 180 s of rotation.

[0054] 3. Low shear / high shear viscosity ratio: calculated by dividing the apparent viscosity at 0.3 r / min by the apparent viscosity at 30 r / min.

[0055] 4. Microgel particles: Take 100 mL of sample and pass it through a stainless steel sieve with a pore size of 150 μm. Rinse with 200 mL of blank solution with the same alcohol-water composition as the sample but without thickening polymer. Count the swollen particles that can be identified on the sieve using a 10x stereomicroscope.

[0056] 5. Intra-batch viscosity variation coefficient: Samples were taken at the beginning, midpoint, and end of the formal collection, and the apparent viscosity at 0.3 r / min was measured. The coefficient was calculated as the ratio of the standard deviation to the mean.

[0057] 6. Viscosity retention after shearing: Take 500 mL of sample and shear it for 60 s at 10,000 r / min using a laboratory rotor-stator homogenizer at 20±1℃. After standing for 30 min, measure the apparent viscosity at 0.3 r / min. Calculate the viscosity retention rate by the ratio of viscosity after shearing to viscosity before shearing.

[0058] 7. Freezing point: The temperature of the first stable crystallization plateau was recorded under continuous slow stirring conditions using a calibrated cryogenic bath and platinum resistance thermometer.

[0059] 8. Storage stability: The sample was sealed and stored at 23±2℃ for 90 days. The apparent viscosity at 0.3 r / min was measured under the same conditions, and the rate of change relative to the initial value was calculated.

[0060] 9. Statistical method: Three batches were prepared independently for each example; results are expressed as the mean ± standard deviation of the three batches. The first, middle, and last sampling points of each batch were used to evaluate intra-batch homogeneity and were not used as independent batches for calculating the standard deviation.

[0061] Example 1: Preferred continuous preparation process of 6% cross-linked polyacrylic acid concentrate (1) Preparation of pre-thickening concentrated thickener. 17.5 L of ethylene glycol and 17.5 L of deionized water were added to the first preparation tank and stirred at 60 r / min at 25°C. 3.00 kg of cross-linked polyacrylic acid thickening polymer was added uniformly over 20 min and allowed to stand at 25°C for 6 h for pre-swelling; then stirred at 100 r / min for 30 min. A 10% sodium hydroxide aqueous solution was slowly added to adjust the pH to 7.4–7.6, and then deionized water was added to make the total mass of the system 50.00 kg. The mixture was stirred at 80 r / min for 20 min to obtain a pre-thickening concentrated thickener with a thickening polymer content of 6.0%.

[0062] (2) Preparation of alcohol-water base solution. Prepare 600.00 kg of alcohol-water base solution according to the general preparation method, wherein the content of ethylene glycol is 55.0 wt%.

[0063] (3) Online mixing and shear homogenization. The pre-thickened concentrated thickener and the alcohol-water base liquid were fed at 30 L / h and 450 L / h respectively, so that they entered the pipeline online mixing device equipped with 12 spiral static mixing elements at a volume flow ratio of 1:15. The preliminary mixture was continuously fed into the online high-speed dispersion device and shear homogenized at 15,000 r / min. The system first discharged material into the recovery container for 10 min, and after the flow rate and outlet temperature stabilized, it was continuously collected for 60 min, and samples were taken at the beginning, middle and end of the time.

[0064] Results: The densities of the pre-thickened concentrated thickener and the alcohol-water base solution were 1.037±0.003 kg / L and 1.045±0.002 kg / L, respectively; the coefficient of variation of the continuous flow rate of the concentrated solution was 1.7±0.3%, and no flow interruption or blockage occurred. The outlet temperature was 29.6±0.8℃, and the thickening polymer content in the final product was 0.372±0.006 wt%. The apparent viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 12,200±300 mPa·s, 3,450±110 mPa·s, and 1,140±45 mPa·s, respectively, with a low-shear / high-shear viscosity ratio of 10.70±0.32; the number of microgel particles was 1.0±0.6 per 100 mL; the intra-batch viscosity variation coefficient was 1.4±0.3%; the viscosity retention after shearing was 96.8±1.0%; the freezing point was -36.8±0.3℃; and the viscosity change rate over 90 days was -2.6±0.7%.

[0065] Example 2: Continuous preparation near the lower limit of process parameters (1) Add 35 L of ethylene glycol and 17.5 L of deionized water to the first preparation tank and mix them evenly at 10°C. Add 1.60 kg of pre-neutralized crosslinked polyacrylic acid thickening polymer over 15 min and pre-swell at 10°C for 2 h; then stir at 50 r / min for 30 min and add deionized water to make the total mass of the system 80.00 kg, to obtain a pre-thickening concentrated thickener with a polymer content of 2.0 wt%.

[0066] (2) Prepare 400.00 kg of alcohol-water base solution according to the general preparation method, wherein the ethylene glycol content is 70.0 wt%.

[0067] (3) The two materials are conveyed at 60 L / h and 300 L / h respectively, so that the volumetric flow rate ratio is 1:5; after initial mixing by 8 static mixing elements, single-pass shear homogenization is performed at 5,000 r / min. After the system discharge is stable for 10 min, samples are continuously collected for 60 min and taken.

[0068] Results: The densities of the two materials were 1.076±0.003 kg / L and 1.087±0.002 kg / L, respectively; the coefficient of variation of the concentrate flow rate was 2.3±0.4%, the outlet temperature was 25.8±0.6℃, and the final polymer content was 0.331±0.006wt%. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 10,300±350, 3,000±120, and 1,040±50 mPa·s, respectively, with a viscosity ratio of 9.90±0.38; the microgel content was 5.0±2.0 particles / 100 mL; the intra-batch viscosity variation coefficient was 2.8±0.6%; the viscosity retention after shearing was 98.0±0.9%; the freezing point was -48.2±0.4℃; and the viscosity change rate over 90 days was -4.2±1.0%.

[0069] Example 3: Continuous preparation of 15% low-viscosity carboxymethyl cellulose concentrate and process parameters near the upper limit (1) Low-viscosity grade carboxymethyl cellulose was used, and its 2 wt% aqueous solution had an apparent viscosity of 25-50 mPa·s at 25°C. 4 L of diethylene glycol and 8 L of deionized water were added to the first preparation tank with a jacket, and stirred at 80 r / min at 40°C. 3.00 kg of carboxymethyl cellulose was added in 6 batches, and stirred for 5 min after each batch. After all the cellulose was added, it was pre-swelled at 40°C for 12 h, then stirred at 200 r / min for 30 min, and deionized water was added to make the total mass of the system 20.00 kg, resulting in a concentrated solution with a polymer content of 15.0 wt%.

[0070] (2) Prepare 520.00 kg of alcohol-water base solution according to the general preparation method, wherein the diethylene glycol content is 55.0 wt%.

[0071] (3) A volumetric metering pump is used to deliver the concentrate and the base liquid at 8 L / h and 400 L / h respectively, so that the volumetric flow rate ratio is 1:50. After the two materials are initially mixed by 16 spiral mixing elements, they are subjected to single-pass shear homogenization at 30,000 r / min. The concentrate is kept at 35-40℃ during the delivery process. After the system discharge is stable for 10 min, the concentrate is collected for 60 min and then sampled.

[0072] Results: The densities of the two materials were 1.070±0.004 kg / L and 1.060±0.003 kg / L, respectively; the coefficient of variation of the concentrate flow rate was 4.0±0.8%; the metering pump outlet pressure was 0.38–0.48 MPa, and no clogging occurred. The outlet temperature was 39.0±1.2℃, and the final polymer content was 0.297±0.007 wt%. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 9,300±420, 2,880±130, and 1,150±55 mPa·s, respectively, with a viscosity ratio of 8.09±0.40; the microgel density was 3.3±1.5 per 100 mL; the intra-batch viscosity variation coefficient was 3.2±0.7%; the viscosity retention after shearing was 90.8±2.0%; the freezing point was -38.0±0.5℃; and the viscosity change rate over 90 days was -5.0±1.1%.

[0073] Example 4: Continuous preparation of 3% cross-linked polyacrylic acid concentrate (1) Add 15 L of ethylene glycol and 15 L of deionized water to the first preparation tank and mix at 20°C. Add 1.65 kg of cross-linked polyacrylic acid polymer and pre-swell at 20°C for 4 h; stir at 80 r / min for 30 min, adjust the pH to 7.4±0.1 with 10 wt% sodium hydroxide aqueous solution, and then add deionized water to make the total mass of the system 55.00 kg, to obtain a pre-thickening concentrated thickener with a polymer content of 3.0 wt%.

[0074] (2) Prepare 520.00 kg of an alcohol-water base solution with an ethylene glycol content of 50.0 wt% according to the general method.

[0075] (3) The two materials were transported at 40 L / h and 400 L / h respectively, so that the volumetric flow rate ratio was 1:10; after initial mixing by 12 static mixing elements, they were homogenized in a single pass at 10,000 r / min. After stabilization for 10 min, samples were collected for 60 min.

[0076] Results: The densities of the two materials were 1.040±0.003 kg / L and 1.045±0.002 kg / L, respectively, with a final polymer content of 0.272±0.005 wt%; the outlet temperature was 27.3±0.7℃. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 10,500±320, 3,150±115, and 1,060±45 mPa·s, respectively, with a viscosity ratio of 9.91±0.35; the microgel content was 2.0±1.0 particles / 100 mL; the intra-batch viscosity variation coefficient was 1.9±0.4%; the viscosity retention after shearing was 97.5±1.0%; the freezing point was -32.6±0.4℃; and the viscosity change rate over 90 days was -3.4±0.8%.

[0077] Example 5: Continuous preparation of 8% cross-linked polyacrylic acid concentrate (1) Add 8 L of ethylene glycol and 8 L of deionized water to the first preparation tank and mix at 30°C. Add 2.40 kg of cross-linked polyacrylic acid polymer and pre-swell at 30°C for 8 h; stir at 150 r / min for 30 min, adjust the pH to 7.6±0.1 with 10 wt% sodium hydroxide aqueous solution, and add deionized water to make the total mass of the system 30.00 kg, to obtain a concentrated solution with a polymer content of 8.0 wt%.

[0078] (2) Prepare 520.00 kg of an alcohol-water base solution with an ethylene glycol content of 60.0 wt% according to the general method.

[0079] (3) The two materials are conveyed at 20 L / h and 400 L / h respectively, so that the volumetric flow rate ratio is 1:20; after initial mixing by 12 spiral static mixing elements, they are homogenized in a single pass at 20,000 r / min. After stabilization for 10 min, the samples are collected for 60 min and taken.

[0080] Results: The densities of the two materials were 1.050±0.003 kg / L and 1.060±0.003 kg / L, respectively, with a final polymer content of 0.378±0.007 wt%; the outlet temperature was 33.1±0.9℃. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 12,500±360, 3,500±120, and 1,100±45 mPa·s, respectively, with a viscosity ratio of 11.36±0.38; the microgel content was 1.0±0.6 particles / 100 mL; the intra-batch viscosity variation coefficient was 1.6±0.3%; the viscosity retention after shearing was 94.8±1.4%; the freezing point was -40.2±0.4℃; and the viscosity change rate over 90 days was -3.5±0.8%.

[0081] Example 6: Continuous preparation of non-crosslinked polyacrylic acid thickening system (1) Non-crosslinked polyacrylic acid with a viscosity-average molecular weight of 5×10^5~1×10^6 was selected. 12 L of ethylene glycol and 12 L of deionized water were added to the first preparation tank and mixed at 25°C. 1.80 kg of polyacrylic acid was added and pre-swollen for 6 h. The mixture was stirred at 100 r / min for 30 min. The pH was adjusted to 7.2±0.1 using a 10 wt% sodium hydroxide aqueous solution. Deionized water was added to make the total mass of the system 45.00 kg, resulting in a concentrated solution with a polymer content of 4.0 wt%.

[0082] (2) Prepare 460.00 kg of an alcohol-water base solution with an ethylene glycol content of 50.0 wt% according to the general method.

[0083] (3) The two materials are conveyed at 30 L / h and 360 L / h respectively, so that the volume flow ratio is 1:12; after initial mixing by 12 static mixing elements, they are homogenized in one pass at 12,000 r / min.

[0084] Results: The densities of the two materials were 1.045±0.003 kg / L and 1.050±0.002 kg / L, respectively, with a final polymer content of 0.306±0.006 wt%; the outlet temperature was 28.4±0.7℃. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 9,200±330, 2,950±120, and 1,100±50 mPa·s, respectively, with a viscosity ratio of 8.36±0.34; the microgel content was 3.0±1.0 particles / 100 mL; the intra-batch viscosity variation coefficient was 2.4±0.5%; the viscosity retention after shearing was 96.0±1.2%; the freezing point was -34.6±0.4℃; and the viscosity change rate over 90 days was -4.8±1.0%.

[0085] Example 7: Continuous preparation of xanthan gum thickening system (1) Add 10 L of ethylene glycol, 10 L of propylene glycol and 20 L of deionized water to the first preparation tank, mix at 20°C, add 1.65 kg of xanthan gum and pre-swell for 4 h; stir at 80 r / min for 30 min, add deionized water to make the total mass of the system 55.00 kg, and obtain a concentrated solution with a xanthan gum content of 3.0 wt%.

[0086] (2) Prepare 520.00 kg of alcohol-water base solution according to the general method, wherein ethylene glycol and propylene glycol each account for 25.0 wt%, and the total alcohol content is 50.0 wt%.

[0087] (3) The two materials are conveyed at 40 L / h and 400 L / h respectively, so that the volume flow ratio is 1:10; after initial mixing by 12 static mixing elements, they are homogenized in one pass at 10,000 r / min.

[0088] Results: The densities of the two materials were 1.055±0.003 kg / L and 1.060±0.002 kg / L, respectively, with a final xanthan gum content of 0.272±0.005 wt%; the outlet temperature was 27.5±0.7℃. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 13,100±420, 3,550±130, and 1,020±45 mPa·s, respectively, with a viscosity ratio of 12.84±0.45; the microgel density was 1.7±0.6 particles / 100 mL; the intra-batch viscosity variation coefficient was 1.9±0.4%; the viscosity retention after shearing was 97.4±1.1%; the freezing point was -35.8±0.4℃; and the viscosity change rate over 90 days was -3.3±0.8%.

[0089] Example 8: Continuous preparation of guar gum thickening system and composite pipeline mixing element (1) Add 10 L of ethylene glycol and 15 L of deionized water to the first preparation tank and mix at 35°C. Add 1.80 kg of guar gum within 20 min and pre-swell for 10 h. Stir at 180 r / min for 30 min and add deionized water to make the total mass of the system 45.00 kg, and obtain a concentrated solution with a guar gum content of 4.0 wt%.

[0090] (2) Prepare 460.00 kg of an alcohol-water base solution with an ethylene glycol content of 55.0 wt% according to the general method.

[0091] (3) The two materials are transported at 30 L / h and 360 L / h respectively, so that the volume flow ratio is 1:12; 6 static mixing elements and 6 spiral mixing units are set in sequence in the pipeline online mixing device, and the preliminary mixed materials are homogenized in one pass at 18,000 r / min.

[0092] Results: The densities of the two materials were 1.067±0.003 kg / L and 1.074±0.003 kg / L, respectively, with a final guar gum content of 0.306±0.006 wt%; the outlet temperature was 31.2±0.9℃. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 11,400±430, 3,280±140, and 1,070±50 mPa·s, respectively, with a viscosity ratio of 10.65±0.44; the microgel content was 3.0±1.0 particles / 100 mL; the intra-batch viscosity variation coefficient was 2.3±0.5%; the viscosity retention after shearing was 93.6±1.6%; the freezing point was -39.2±0.5℃; and the viscosity change rate over 90 days was -4.9±1.0%.

[0093] Example 9: Continuous preparation of hydroxyethyl cellulose thickening system (1) Add 5 L of ethylene glycol, 5 L of diethylene glycol and 10 L of deionized water to the first preparation tank, mix at 30°C, add 2.40 kg of hydroxyethyl cellulose in batches and pre-swell for 8 h; stir at 150 r / min for 30 min, add deionized water to make the total mass of the system 30.00 kg, and obtain a concentrated solution with a hydroxyethyl cellulose content of 8.0 wt%.

[0094] (2) Prepare 520.00 kg of alcohol-water base solution according to the general method, wherein ethylene glycol and diethylene glycol each account for 30.0 wt%, and the total alcohol content is 60.0 wt%.

[0095] (3) The two materials are conveyed at 20 L / h and 400 L / h respectively, so that the volume flow ratio is 1:20; after initial mixing by the spiral mixing unit, single-pass homogenization is carried out at 20,000 r / min.

[0096] Results: The densities of the two materials were 1.085±0.004 kg / L and 1.080±0.003 kg / L, respectively, with a final hydroxyethyl cellulose content of 0.383±0.008 wt%; the outlet temperature was 32.3±1.0℃. The viscosities at 0.3 r / min, 6 r / min, and 30 r / min were 10,700±360, 3,150±120, and 1,100±50 mPa·s, respectively, with a viscosity ratio of 9.73±0.39; the microgel content was 2.0±1.0 particles / 100 mL; the intra-batch viscosity variation coefficient was 2.1±0.4%; the viscosity retention after shearing was 94.0±1.5%; the freezing point was -43.8±0.4℃; and the viscosity change rate over 90 days was -4.7±0.9%.

[0097] Example 10: Validation of Continuous Production System, Closed-Loop Control, and Qualified Product Diversion (1) System Setup. The first preparation unit uses a preparation tank with an effective volume of 500 L, equipped with a jacketed temperature control and a low-speed stirring mechanism; its outlet is connected in sequence to the first metering pump and the volumetric flow meter. The second preparation unit uses a preparation tank with an effective volume of 2,000 L; its outlet is connected in sequence to the second metering pump and the volumetric flow meter. The two streams of material enter the online mixing device with two independent feed ports on a DN32 pipeline, and then enter the rotor-stator online high-speed dispersion device through a 0.8 m connecting pipe. The outlet of the high-speed dispersion device is equipped with a temperature sensor, an online viscosity detection device, a sampling port, and a three-way switching valve in sequence. The three-way switching valve is connected to the dispensing unit and the recovery unit respectively.

[0098] (2) Normal operation. Two streams of material were prepared according to Example 1. The flow rates of the first and second metering pumps were set to 20 L / h and 300 L / h, respectively, and the rotor speed was set to 15,000 r / min. After the system was started, the material was discharged to the recycling unit for 10 min. When the flow rate deviation of the two streams did not exceed 3.0%, the outlet temperature did not exceed 38℃, and the online viscosity was within ±8.0% of the set center value for 30 s, the system was switched to the dispensing unit and operated continuously for 4 h.

[0099] (3) Viscosity closed-loop disturbance test. After 60 minutes of stable operation, the flow rate of the first metering pump was artificially reduced by 10% and maintained for 3 minutes. When the online viscosity deviated from the set center value by more than 8.0% for 30 seconds, the controller switched the three-way switching valve to the recovery unit; then the controller increased the flow rate of the first metering pump, and switched back to the dispensing unit after the online viscosity returned to the set range and stabilized for 60 seconds.

[0100] (4) Freezing point split test. Samples are taken from the sampling port every 30 minutes for near-line freezing point detection. After 150 minutes of stable operation, the second preparation unit is replaced with pre-prepared low-alcohol base liquid for 10 minutes. When the near-line detected freezing point is higher than -30℃, the controller keeps the three-way switching valve pointing to the recovery unit. After resuming the use of normal base liquid, the system is switched to the dispensing unit only when the freezing point of two consecutive samples is not higher than -30℃ and the online viscosity is within the preset range.

[0101] Results: During normal operation, the average flow rates of the first and second streams were 20.05±0.16 L / h and 300.2±1.6 L / h, respectively, with a maximum deviation of 1.6% in the volumetric flow rate ratio. The outlet pressure of the first metering pump was 0.26–0.31 MPa, the rotor speed fluctuation did not exceed ±90 r / min, and the outlet temperature was 29.5±0.7℃. The relative deviation between online and offline viscosity was no greater than 3.1%. A viscosity disturbance triggered recovery and diversion 45±8 s later, and the dispensing conditions were restored to normal within 96±15 s after the flow rate returned to normal. The near-line freezing point of the low-alcohol base liquid after entering the system was -28.6±0.4℃, and all related materials were directed to the recovery unit; after restoring normal base liquid, the freezing point returned to -36.7±0.3℃. During a 4-hour operation, 1,315±15 kg of qualified product was obtained, with a qualified product yield of 98.1±0.5% during the stable phase.

[0102] III. Summary of Results from Examples Example Thickening polymer Concentrate / % Flow ratio Rotational speed (r / min) Final polymer / % Viscosity at 0.3 r / min viscosity ratio microgels CV / % Retention rate / % Freezing point / °C 1 Cross-linked polyacrylic acid 6 1:15 15,000 0.372 12,200 10.70 1.0 1.4 96.8 -36.8 2 Pre-neutralized crosslinked polyacrylic acid 2 1:5 5,000 0.331 10,300 9.90 5.0 2.8 98.0 -48.2 3 Low viscosity carboxymethyl cellulose 15 1:50 30,000 0.297 9,300 8.09 3.3 3.2 90.8 -38.0 4 Cross-linked polyacrylic acid 3 1:10 10,000 0.272 10,500 9.91 2.0 1.9 97.5 -32.6 5 Cross-linked polyacrylic acid 8 1:20 20,000 0.378 12,500 11.36 1.0 1.6 94.8 -40.2 6 non-crosslinked polyacrylic acid 4 1:12 12,000 0.306 9,200 8.36 3.0 2.4 96.0 -34.6 7 Xanthan Gum 3 1:10 10,000 0.272 13,100 12.84 1.7 1.9 97.4 -35.8 8 Guar gum 4 1:12 18,000 0.306 11,400 10.65 3.0 2.3 93.6 -39.2 9 Hydroxyethyl cellulose 8 1:20 20,000 0.383 10,700 9.73 2.0 2.1 94.0 -43.8 I. Comparative Standards and Testing Methods (a) Common benchmark Except for Comparative Examples 1 and 2, which were prepared in batches, the pre-thickening concentrated thickener, alcohol-water base solution, metering pump, pipeline, rotor-stator homogenizing head, and sampling procedure used in Comparative Examples 3-6 were the same as in Example 1. The pre-thickening concentrated thickener contained 6.0% cross-linked polyacrylic acid polymer by mass and had a pH of 7.4-7.6; the alcohol-water base solution contained 55.0% ethylene glycol by mass.

[0103] In the continuous process, the set flow rates of the pre-thickened concentrated thickener and the alcohol-water base liquid are 30 L / h and 450 L / h, respectively, with a volumetric flow rate ratio of 1:15. After the system is started, the material is first discharged into the recovery container for 10 min, followed by continuous collection for 60 min; samples are taken at the start of formal collection, 30 min, and 60 min.

[0104] Comparative Examples 1 and 2 were both prepared on a scale of 1,000 kg of finished product. The raw materials used in Comparative Example 1 were converted according to the actual composition of the finished product per unit mass in Example 1, wherein the amount of cross-linked polyacrylic acid thickening polymer was 3.72 kg, the total amount of ethylene glycol was approximately 538.4 kg, disodium ethylenediaminetetraacetate was 0.28 kg, sodium benzoate was 0.94 kg, C12-C14 fatty alcohol polyoxyethylene (7) ether was 1.41 kg, silicone defoamer was 0.09 kg, and water-soluble green dye was 0.02 kg, and deionized water was added to make up to 1,000 kg; the pH was adjusted to 7.4-7.6 using a 10% sodium hydroxide aqueous solution.

[0105] Comparative Example 2 used 62.1 kg of the 6.0% pre-thickening concentrated thickener and 937.9 kg of the 55.0% ethylene glycol aqueous base liquid described in Example 1 to make the final material composition basically the same as that in Example 1.

[0106] (II) Detection and Statistical Methods 1. The apparent viscosity of all samples was measured at 20.0±0.2℃ using a Brookfield DV2T rotational viscometer or equivalent instrument and an LV-2 rotor; new parallel samples were used at 0.3 r / min, 6 r / min and 30 r / min, and the readings were taken after 180 s of rotation.

[0107] 2. The low-shear / high-shear viscosity ratio is the ratio of apparent viscosity at 0.3 r / min to apparent viscosity at 30 r / min.

[0108] 3. Microgel particles were counted under a 10x stereomicroscope after passing 100 mL of sample through a 150 μm sieve, rinsing with a blank solution of alcohol and water of the same composition without thickening polymer.

[0109] 4. The coefficient of variation of intra-batch viscosity is calculated based on the apparent viscosity at 0.3 r / min from three sampling points at the beginning, middle, and end of the same batch.

[0110] 5. The viscosity retention rate after shearing was determined according to the unified detection method in the example, that is, after the sample was sheared at 10,000 r / min for 60 s and allowed to stand for 30 min, the ratio of the apparent viscosity after shearing to that before shearing at 0.3 r / min was calculated.

[0111] 6. Each comparative example was tested independently in 3 batches. The results in the table are expressed as the mean ± standard deviation of the 3 batches. The methods for determining and calculating freezing point, 90-day storage stability, and energy consumption are the same as in the examples.

[0112] 7. The main production line processing time is calculated from the start of feeding materials for the final finished product or when two materials enter the continuous production line, until the product reaches a state where it can be packaged or when stable collection is completed; the time for pre-preparing the pre-thickened concentrated thickener is not included in the main production line processing time.

[0113] Comparative Example 1: Solid thickening polymer was directly fed into a kettle and stirred at low speed. (1) Preparation of alcohol-water system. Add about 400 kg of deionized water to a preparation vessel with an effective volume of not less than 1,500 L, equipped with a jacket and anchor stirrer, and add 0.28 kg of disodium ethylenediaminetetraacetate, 0.94 kg of sodium benzoate, 1.41 kg of C12-C14 fatty alcohol polyoxyethylene (7) ether, 0.09 kg of organosilicon defoamer and 0.02 kg of water-soluble green dye in sequence, and stir until dissolved or uniformly dispersed; add 538.4 kg of ethylene glycol, and adjust the system with deionized water so that the final total mass after adding thickening polymer and neutralizing agent is 1,000 kg.

[0114] (2) Direct addition of solid powder. The material temperature is controlled at 25±1℃, and the mixture is stirred at 100 r / min. 3.72 kg of cross-linked polyacrylic acid thickening polymer powder is evenly sprinkled onto the liquid surface within 45 min, without increasing the stirring speed during addition. After addition, stirring is continued at 100 r / min for 6 h; then, 10 wt% sodium hydroxide aqueous solution is slowly added to adjust the pH to 7.4-7.6, and stirring is continued for 60 min. This material does not pass through an online mixing device or an online high-speed dispersion device.

[0115] (3) Sampling. After stopping stirring, let stand for 30 minutes, and take samples from the top, middle and bottom of the preparation vessel respectively, and test them according to the common detection method.

[0116] Results: The apparent viscosities of the product at 0.3 r / min, 6 r / min, and 30 r / min were 9,450±700, 2,850±250, and 1,020±90 mPa·s, respectively; the low-shear / high-shear viscosity ratio was 9.26±0.55; the number of microgel particles on a 150 μm sieve was 62±10 / 100 mL; the intra-batch low-shear viscosity coefficient of variation was 10.6±1.5%; the viscosity retention rate after shearing was 86.2±3.0%; the freezing point was -36.7±0.3℃; and the viscosity change rate over 90 days was -13.8±2.1%. The processing time of the main production line from initial feeding to reaching a reproducible state was 455±25 min / t, and the unit energy consumption of the main production line was 28.5±2.4 kWh / t. Numerous swollen agglomerates were observed in the samples, and significant differences in viscosity were observed in samples from the upper, middle, and lower parts of the reactor.

[0117] Comparative Example 2: A pre-thickened concentrated thickener was used, but it was only mixed at a low speed in the preparation vessel. (1) Add 937.9 kg of the alcohol-water base solution described in Example 1 to the preparation vessel with an anchor stirrer and stir at 100 r / min at 25±1℃.

[0118] (2) 62.1 kg of the 6.0% pre-thickened concentrated thickener described in Example 1 was continuously added to the alcohol-water base solution over 30 min. After the addition was completed, stirring was continued at 100 r / min for 150 min. No pipeline online mixing device or online high-speed dispersion equipment was used in the entire process.

[0119] (3) After stopping stirring, let stand for 30 minutes, and take samples from the top, middle and bottom of the preparation vessel for testing.

[0120] Results: The apparent viscosities of the product at 0.3 r / min, 6 r / min, and 30 r / min were 10,850±520, 3,200±180, and 1,090±65 mPa·s, respectively; the low-shear / high-shear viscosity ratio was 9.95±0.43; the number of microgel particles was 14±4 / 100 mL; the intra-batch low-shear viscosity coefficient of variation was 6.2±0.9%; the viscosity retention after shearing was 92.6±2.3%; the freezing point was -36.8±0.3℃; and the viscosity change rate over 90 days was -8.4±1.4%. The main production line processing time was 230±15 min / t, and the unit energy consumption of the main production line was 18.6±1.5 kWh / t. Compared with Comparative Example 1, the number of fish eyes was significantly reduced, but a viscosity gradient still existed at different locations within the reactor, indicating that pre-thickening treatment cannot replace subsequent continuous two-stage mixing.

[0121] Comparative Example 3: Static mixing in the pipeline only, without rotor-stator shear homogenization. (1) Prepare a 6.0% pre-thickened concentrated thickener and a 55.0% ethylene glycol aqueous base solution according to Example 1. Feed the two materials into the same online mixing device as in Example 1 at 30 L / h and 450 L / h, respectively.

[0122] (2) Twelve spiral static mixing elements are installed in the pipeline online mixing device. The outlet of the static mixer is directly connected to the clean collection container and completely bypasses the online high-speed dispersion equipment. After the system discharge stabilizes for 10 minutes, continuous collection is carried out for 60 minutes, and samples are taken at the beginning, middle and end of the time.

[0123] Results: The static mixer outlet temperature was 24.8±0.5℃. The apparent viscosities of the product at 0.3 r / min, 6 r / min, and 30 r / min were 10,100±450, 3,100±160, and 1,080±55 mPa·s, respectively, with a viscosity ratio of 9.35±0.40; the number of microgel particles was 23±6 / 100 mL; the intra-batch low-shear viscosity coefficient of variation was 6.8±1.1%; the viscosity retention after shearing was 93.4±2.0%; the freezing point was -36.8±0.3℃; and the 90-day viscosity change rate was -9.7±1.5%. The main production line processing time was 120±2 min / t, and the unit energy consumption was 4.2±0.3 kWh / t. While the energy consumption was low, identifiable soft gel clumps were still present in the samples, indicating that the shear strength provided by static mixing was insufficient for single-pass fine homogenization.

[0124] Comparative Example 4: Static initial mixing in the pipeline is eliminated, and the two material streams merge directly at the inlet of the high-speed dispersion equipment. (1) Prepare two streams of material according to Example 1, and set the flow rates to 30 L / h and 450 L / h respectively. Remove the online mixing device in the pipeline and connect the two feed pipes through a T-joint; the straight pipe length between the outlet of the T-joint and the inlet of the rotor-stator homogenizing working head is 100 mm.

[0125] (2) The two materials are directly merged at the T-joint and immediately fed into the online high-speed dispersion device for single-pass shearing homogenization at 15,000 r / min. After the system discharge stabilizes for 10 min, continuous collection is carried out for 60 min and samples are taken.

[0126] (3) In addition to the common test items, continuously record the inlet pressure of the high-speed dispersion equipment and the instantaneous flow rate of the two materials.

[0127] Results: The outlet temperature of the high-speed dispersion equipment was 29.1±1.0℃; the relative fluctuation range of the inlet pressure was ±8.5%, significantly higher than ±2.6% in Example 1. The apparent viscosities of the product at 0.3 r / min, 6 r / min, and 30 r / min were 10,700±430, 3,200±140, and 1,100±50 mPa·s, respectively, with a viscosity ratio of 9.73±0.36; the number of microgel particles was 7±3 / 100 mL; the intra-batch low-shear viscosity variation coefficient was 4.9±0.8%; the viscosity retention rate after shearing was 94.9±1.6%; the freezing point was -36.8±0.3℃; and the viscosity change rate over 90 days was -6.8±1.2%. The main production line processing time was 120±2 min / t, and the unit energy consumption was 12.1±0.6 kWh / t. The viscosity of the samples in the front, middle and rear sections fluctuated periodically, indicating that when the high-viscosity concentrate enters the working head without static initial mixing, the instantaneous ratio fluctuation at the inlet cannot be completely eliminated by a single high-speed shearing.

[0128] Comparative Example 5: The rotor speed of the online high-speed dispersion equipment is lower than the specified range. (1) Two streams of material were prepared according to Example 1 and fed into an online mixing device with 12 spiral static mixing elements at 30 L / h and 450 L / h respectively.

[0129] (2) The preliminary mixture was continuously fed into the same online high-speed dispersion equipment as in Example 1, but the rotor speed was set to 3,000 r / min. The remaining working head structure, connecting pipe length, system stabilization time, collection time and sampling method were the same as in Example 1.

[0130] Results: The outlet temperature was 25.2±0.6℃. The apparent viscosities of the product at 0.3 r / min, 6 r / min, and 30 r / min were 10,200±480, 3,150±150, and 1,060±55 mPa·s, respectively, with a viscosity ratio of 9.62±0.42; the number of microgel particles was 18±5 / 100 mL; the intra-batch low-shear viscosity variation coefficient was 5.5±0.9%; the viscosity retention after shearing was 98.5±0.8%; the freezing point was -36.8±0.3℃; and the 90-day viscosity change rate was -7.2±1.3%. The main production line processing time was 120±2 min / t, and the unit energy consumption was 8.0±0.4 kWh / t. This group showed relatively low polymer network disruption, but the rotation speed was insufficient to fully eliminate soft gels and local concentration differences in a single pass.

[0131] Comparative Example 6: The rotor speed of the online high-speed dispersion equipment exceeds the specified range. (1) Two streams of material were prepared according to Example 1 and statically mixed in the pipeline at 30 L / h and 450 L / h.

[0132] (2) The rotor speed of the online high-speed dispersion device was set to 35,000 r / min. The other equipment structure, connection method, system stabilization time and collection time were the same as in Example 1. The cooling conditions of Example 1 were not actively changed, and the outlet temperature was continuously recorded. The test was stopped immediately when the outlet temperature reached 50°C.

[0133] Results: The outlet temperature was 44.3±1.8℃, and none of the three batches reached the 50℃ shutdown limit. The apparent viscosities of the product at 0.3 r / min, 6 r / min, and 30 r / min were 8,050±360, 2,450±120, and 1,010±45 mPa·s, respectively, with a viscosity ratio of 7.97±0.33; the number of microgel particles was 0.3±0.6 / 100 mL; the intra-batch low-shear viscosity variation coefficient was 1.7±0.4%; the viscosity retention rate after shearing was 72.4±2.8%; the freezing point was -36.8±0.3℃; and the viscosity change rate over 90 days was -10.9±1.8%. The main production line processing time was 120±2 min / t, and the unit energy consumption was 20.5±1.1 kWh / t. Although the microgels were largely eliminated and the batch uniformity was good, the low-shear viscosity and post-shear retention rate decreased significantly, indicating that the temperature rise and excessive shear caused by the high rotation speed damaged the polymer network.

[0134] III. Summary of Results from Example 1 and Comparative Examples Table 1 Rheological properties, uniformity and stability Group Viscosity at 0.3 r / min (mPa·s) Viscosity at 6 r / min (mPa·s) Viscosity at 30 r / min (mPa·s) viscosity ratio Microgels / (each per 100 mL) Intra-batch CV / % Shear retention rate / % 90-day change rate / % Example 1 12,200±300 3,450±110 1,140±45 10.70±0.32 1.0±0.6 1.4±0.3 96.8±1.0 -2.6±0.7 Comparative Example 1 9,450±700 2,850±250 1,020±90 9.26±0.55 62±10 10.6±1.5 86.2±3.0 -13.8±2.1 Comparative Example 2 10,850±520 3,200±180 1,090±65 9.95±0.43 14±4 6.2±0.9 92.6±2.3 -8.4±1.4 Comparative Example 3 10,100±450 3,100±160 1,080±55 9.35±0.40 23±6 6.8±1.1 93.4±2.0 -9.7±1.5 Comparative Example 4 10,700±430 3,200±140 1,100±50 9.73±0.36 7±3 4.9±0.8 94.9±1.6 -6.8±1.2 Comparative Example 5 10,200±480 3,150±150 1,060±55 9.62±0.42 18±5 5.5±0.9 98.5±0.8 -7.2±1.3 Comparative Example 6 8,050±360 2,450±120 1,010±45 7.97±0.33 0.3±0.6 1.7±0.4 72.4±2.8 -10.9±1.8 Table 2 Process conditions, freezing point and process efficiency Group The only condition to change Outlet temperature / °C Freezing point / °C Mainline processing time (min / t) Mainline energy consumption (kWh / t) Main phenomena Example 1 Static initial mixing + online homogenization at 15,000 r / min 29.6±0.8 -36.8±0.3 120±2 12.4±0.6 Evenly distributed, network remains well maintained Comparative Example 1 Direct feeding of solid powder + low-speed mixing in a kettle 25.0±0.6 -36.7±0.3 455±25 28.5±2.4 There are many fish eyes, and the positions inside the pot are significantly different. Comparative Example 2 Pre-thickened concentrate + slow-speed stirring in a kettle 25.1±0.5 -36.8±0.3 230±15 18.6±1.5 Fisheye reduction, but intra-batch gradient remains significant. Comparative Example 3 Static mixing only 24.8±0.5 -36.8±0.3 120±2 4.2±0.3 Gel residue and insufficient uniformity Comparative Example 4 Cancel static initial mixing, directly merge at the inlet. 29.1±1.0 -36.8±0.3 120±2 12.1±0.6 Inlet pressure fluctuations, viscosity fluctuations in the early, middle and late stages Comparative Example 5 Rotor speed 3,000 r / min 25.2±0.6 -36.8±0.3 120±2 8.0±0.4 Insufficient shearing, the soft gel was not fully eliminated. Comparative Example 6 Rotor speed 35,000 r / min 44.3±1.8 -36.8±0.3 120±2 20.5±1.1 As temperature rises, the polymer network undergoes excessive shearing. The various embodiments of this invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for manufacturing a de-icing and anti-icing fluid for a Type IV aircraft, characterized in that, The steps include: (1) adding the thickening polymer to an alcohol-water mixture, pre-swelling it at 10–40°C for 2–12 hours, and then further swelling it at 50–200°C. The thickening polymer is dispersed by stirring at a speed of rpm, and then deionized water is added to make the mass percentage of the thickening polymer 2% to 15% to obtain a pre-thickening concentrated thickener that can be transported by a metering pump; wherein, the volume ratio of alcohol to water in the alcohol-water mixture is 1:0.5 to 1:2; (2) The freezing point lowering agent is mixed with deionized water to obtain an alcohol-water base liquid; (3) The pre-thickening concentrated thickener and the alcohol-water base liquid are transported separately by independent metering pumps, and the two are continuously fed into the pipeline online mixing device at a volume flow ratio of 1:5 to 1:50, and are initially mixed in the pipeline flow state to obtain a preliminary mixture; (4) The preliminary mixture is continuously transported in the pipeline flow state to an online high-speed dispersion device with a rotor-stator homogenizing working head, and is sheared and homogenized at a rotor speed of 5,000 to 30,000 rpm to obtain the Type IV aircraft de-icing and anti-icing fluid.

2. The manufacturing method according to claim 1, characterized in that, The thickening polymer is selected from at least one of polyacrylic acid, cross-linked polyacrylic acid copolymer, xanthan gum, guar gum, carboxymethyl cellulose and hydroxyethyl cellulose.

3. The manufacturing method according to claim 1, characterized in that, The thickening polymer is a cross-linked polyacrylic acid polymer; the mass percentage of the thickening polymer in the pre-thickening concentrated thickener is 3% to 8%; the volume ratio of alcohol to water in the alcohol-water mixture is 1:

1.

4. The manufacturing method according to claim 1, characterized in that, The freezing point lowering agent and the alcohol in the alcohol-water mixture are each independently selected from at least one of ethylene glycol, propylene glycol, and diethylene glycol; the mass percentage of alcohols in the alcohol-water base solution is 30% to 70%.

5. The manufacturing method according to claim 1, characterized in that, The volume flow ratio of the pre-thickened concentrated thickener to the alcohol-water base liquid in step (3) is 1:10 to 1:

20.

6. The manufacturing method according to claim 1, characterized in that, The pipeline online mixing device is equipped with at least one of a static mixing element and a spiral mixing unit.

7. The manufacturing method according to claim 1, characterized in that, After step (4), the apparent viscosity and freezing point of the obtained Type IV aircraft de-icing and anti-icing fluid are detected online, and the Type IV aircraft de-icing and anti-icing fluid with a freezing point not higher than -30℃ is dispensed.

8. A Type IV aircraft de-icing and anti-icing fluid, characterized in that, Prepared according to the preparation method according to any one of claims 1 to 7.

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