Quantitative calculation method for comprehensive utilization rate of acid in preparation of crude fatty acid process

Abstract

The application discloses a kind of preparation crude fatty acid process in the quantitative calculation method of acid comprehensive utilization rate, belong to the quantitative calculation technical field of acid comprehensive utilization rate, comprising: the acid value of crude fatty acid prepared and the raw material soap stock used in preparation is determined, the amount of substance of acid consumed in acidification reaction is calculated after obtaining corresponding data;Determine the strong acid acidity of total process effluent, the amount of substance of acid remaining in total process effluent is calculated after obtaining corresponding data;According to the amount of substance of acid added and the data calculated above, the amount of substance of acid used to neutralize excess monobasic alkali in saponification reaction is calculated;Finally, the acid comprehensive utilization rate is calculated.The application analyzes acid utilization path by process flow, determines relevant parameters, constructs quantitative method, realizes the quantitative calculation of acid comprehensive utilization rate, is simple and convenient and easy to operate and realizes, can significantly reduce raw material consumption and salt and acidity in wastewater, has important significance to improve product yield and reduce environmental pollution.

Description

TECHNICAL FIELD

[0001] The application relates to a quantitative calculation method for acid comprehensive utilization rate in a crude fatty acid preparation process and belongs to the technical field of quantitative calculation of acid comprehensive utilization rate. BACKGROUND

[0002] Soapstock is a by-product formed in the alkali refining deacidification step of vegetable oil or animal oil refining. Soapstock contains a large amount of fatty acid salts in the form of saponified substances. Direct disposal or low-price treatment is a huge waste of resources. Through acid hydrolysis process (i.e. adding inorganic acids such as sulfuric acid, hydrochloric acid or organic acids), the sodium fatty acid in soapstock can be reconverted into free fatty acid with higher value, becoming an important chemical raw material.

[0003] The existing process for preparing fatty acid from soapstock can be divided into three categories: hydrolysis acidification method, acidification hydrolysis method and saponification acidolysis method. The common ones are acidification hydrolysis method and saponification acidolysis method. In the acidification hydrolysis method, the fractional acidification method (such as patent CN109554230A, the invention name is a method for preparing acidified oil from soapstock) heats the soapstock to 88-92℃, then adds dilute sulfuric acid and circulating acid water, and separates the primary acidified oil. Secondary acidification is carried out, and not less than 90% concentrated sulfuric acid is added to the primary acidified oil for secondary reaction to further degrade phospholipids. The separated acid water is recycled for primary acidification, realizing acid resource recycling. Organic acid (such as oxalic acid) can also be used to replace inorganic acid for acidification of soapstock (such as patent CN117568100A, the invention name is a clean production method for preparing mixed fatty acid from vegetable oil soapstock). The saponification acidolysis method (such as patent CN106753753A, the invention name is an extraction process of mixed fatty acid in vegetable oil foot) first dehydrates and decolorizes the soapstock, then adds sodium hydroxide for saponification (pH is 10-11) to convert neutral oil into saponified substances. Then, sulfuric acid (concentration is 20%) is used for acidification to decompose the saponified substances into free fatty acid. After water washing and reduced pressure distillation purification, the product is obtained.

[0004] The above process shows that in the process of preparing crude fatty acid from soapstock, the addition of acid is the core step of the reaction, which undertakes the key task of "releasing" and "purifying" free fatty acid from soapstock solution.

[0005] The effective components of soapstock itself or its processed soapstock solution are often in the form of fatty acid salts such as potassium soap and sodium soap. Direct addition of inorganic acid (such as sulfuric acid and hydrochloric acid) can provide high concentration of hydrogen ions, which can replace the metal ions (such as K⁺ and Na⁺) in the fatty acid salts, so that the fatty acid salts are converted into crude fatty acid which is insoluble in water.

[0006] The soapstock itself is usually a stable colloid, emulsion system due to its surfactant properties, and oil and water are not easy to separate. The addition of acid solution can effectively neutralize the alkalinity of the system, destroy the Zeta potential (Zeta potential, a physical quantity representing the stability of the colloidal dispersion system, refers to the potential difference between the shear surface and the bulk liquid) and double-layer structure of the colloidal particles, and at the same time, the emulsion film wrapped around the oil is broken. This makes the bound tiny oil droplets coalesce to form larger oil droplets, which quickly float and aggregate due to their density difference, forming a clear fatty acid layer (oil phase), thereby achieving efficient separation from the lower aqueous phase (containing glycerol, salt, acid, water-soluble impurities, etc.). This process greatly improves the yield of fatty acids and the efficiency of subsequent operations. In addition, the acidic environment can effectively inhibit the growth of microorganisms and prevent the deterioration of materials during the process. At the same time, the lower pH value can avoid certain side reactions that easily occur under alkaline conditions, such as resaponification or oxidation of fatty acids, ensuring the quality and stability of the final product.

[0007] The addition of acid not only completes the chemical conversion from saponified material to free fatty acid, but also realizes the effective separation of oil and water phases through physical and chemical actions such as demulsification and coalescence, laying a foundation for subsequent purification steps such as water washing, distillation, and refining.

[0008] However, the existing technology does not disclose a quantitative calculation method for acid comprehensive utilization rate, and the acid comprehensive utilization rate is not clear, which not only affects the input cost, but also has a certain impact on the environment. Quantifying the acid comprehensive utilization rate in the preparation of crude fatty acids can significantly reduce raw material consumption and salt and acidity in wastewater, which has important economic and environmental significance in improving product yield, controlling production cost, and reducing environmental pollution. SUMMARY

[0009] The purpose of the present application is to provide a quantitative calculation method for acid comprehensive utilization rate in the preparation of crude fatty acids to reduce raw material consumption and salt and acidity in wastewater.

[0010] To achieve the above purpose, the present application is implemented by using the following technical solutions:

[0011] The present application provides a quantitative calculation method for acid comprehensive utilization rate in the preparation of crude fatty acids, comprising:

[0012] Analyzing the acid path in the preparation of crude fatty acids, including the amount of substance of acid consumed in acidification reaction, the amount of substance of residual acid in total process water, and the amount of substance of acid used to neutralize excess monobasic alkali in saponification reaction;

[0013] The acid value of the prepared crude fatty acid and the raw material soapstock used in the preparation are determined by the cold solvent indicator method, and after obtaining the first determination data, the amount of substance of acid consumed in acidification reaction is calculated;

[0014] The strong acid acidity of the total process effluent is determined by titration to obtain the second determination data, and the amount of substance of the residual acid in the total process effluent is calculated; wherein the total process effluent includes all non-oil phase liquids separated in the process of preparing crude fatty acid;

[0015] After the amount of substance of the acid added in the process of preparing crude fatty acid is obtained, the amount of substance of the acid used to neutralize the excess monobasic alkali in the saponification reaction is calculated in combination with the amount of substance of the acid consumed in the acidification reaction and the amount of substance of the residual acid in the total process effluent;

[0016] The acid comprehensive utilization rate is calculated according to the amount of substance of the acid consumed in the acidification reaction, the amount of substance of the acid used to neutralize the excess monobasic alkali in the saponification reaction and the amount of substance of the acid added in the process of preparing crude fatty acid.

[0017] Further, the first determination data includes the volume of monobasic alkali consumed in determining the acid value of soapstock, the volume of monobasic alkali consumed in determining the acid value of crude fatty acid, the molar concentration of monobasic alkali consumed in determining the acid value of crude fatty acid, the mass of prepared crude fatty acid, the mass of the sample of crude fatty acid weighed in determining the acid value of crude fatty acid, the total mass of soapstock added in preparing crude fatty acid and the mass of the sample of soapstock weighed in determining the acid value of soapstock.

[0018] Further, the second determination data includes the volume of monobasic alkali consumed in determining the strong acid acidity of the total process effluent, the molar concentration of monobasic alkali consumed in determining the strong acid acidity of the total process effluent, the volume of the total process effluent and the volume of the effluent taken in determining the strong acid acidity of the total process effluent.

[0019] Further, the non-oil phase liquid includes: separated acid liquid, washing effluent and centrifugal effluent;

[0020] The separated acid liquid is obtained by the following method: after the acidification is completed, the product is allowed to stand and separate into layers to obtain the lower layer of separated acid liquid, denoted as ;

[0021] The washing effluent is obtained by the following method: the upper layer of crude fatty acid oil phase obtained after the standing and separation is washed with deionized water for multiple times until the pH of the lower layer of effluent is 6-7 to obtain the washing effluent, denoted as ;

[0022] The centrifugal effluent is obtained by the following method: the crude fatty acid oil phase after washing is centrifuged, and the obtained water is the centrifugal effluent, denoted as .

[0023] Further, after the amount of substance of the acid added in the process of preparing crude fatty acid is obtained, the amount of substance of the acid used to neutralize the excess monobasic alkali in the saponification reaction is calculated in combination with the amount of substance of the acid consumed in the acidification reaction and the amount of substance of the residual acid in the total process effluent, which is carried out by the following formula:

[0024] ;

[0025] wherein, represents the amount of substance of the acid used to neutralize the excess monobasic base in the saponification reaction, represents the amount of substance of the acid added in the preparation of the crude fatty acid, represents the amount of substance of the acid consumed in the acidification reaction, represents the amount of substance of the acid remained in the total effluent of the process.

[0026] Further, the acid comprehensive utilization rate is calculated according to the amount of substance of the acid consumed in the acidification reaction, the amount of substance of the acid used to neutralize the excess monobasic base in the saponification reaction and the amount of substance of the acid added in the preparation of the crude fatty acid, by the following formula:

[0027] ;

[0028] wherein, represents the acid comprehensive utilization rate, represents the amount of substance of the acid used to neutralize the excess monobasic base in the saponification reaction, represents the amount of substance of the acid added in the preparation of the crude fatty acid, represents the amount of substance of the acid consumed in the acidification reaction.

[0029] Further, the amount of substance of the acid consumed in the acidification reaction is calculated by the following formula:

[0030] ;

[0031] wherein, represents the amount of substance of the acid consumed in the acidification reaction, represents the amount of substance of the monobasic base required to consume the acid in the titration unit, represents the volume of the monobasic base consumed in the determination of the acid value of the crude fatty acid, represents the molar concentration of the monobasic base consumed in the determination of the acid value of the crude fatty acid, represents the mass of the crude fatty acid prepared, represents the mass of the sample of the crude fatty acid weighed in the determination of the acid value of the crude fatty acid, represents the volume of the monobasic base consumed in the determination of the acid value of the soapstock, represents the total mass of the soapstock added in the preparation of the crude fatty acid, represents the mass of the sample of the soapstock weighed in the determination of the acid value of the soapstock.

[0032] Further, the amount of substance of the acid remained in the total effluent of the process is calculated by the following formula:

[0033] ;

[0034] wherein, represents the amount of substance of monobasic alkali consumed by the amount of substance of acid in titration units, represents the amount of substance of acid remaining in the total process effluent, represents the volume of monobasic alkali consumed in determining the strong acid acidity of the total process effluent, represents the molar concentration of monobasic alkali consumed in determining the strong acid acidity of the total process effluent, represents the volume of the total process effluent, represents the volume of effluent fractionated in determining the strong acid acidity of the total process effluent.

[0035] Further, the process for preparing crude fatty acid comprises:

[0036] The soapstock is taken for drying;

[0037] The soapstock is added into a reactor, deionized water is added, and stirring is performed;

[0038] The reactor is connected to a reflux condenser device, the reactor is connected to a stirrer, and the reactor is subjected to water bath;

[0039] Monobasic alkali is added for saponification;

[0040] Acid is added for acidification to obtain an intermediate product;

[0041] The intermediate product is allowed to stand for layer separation to obtain crude fatty acid oil phase in the upper layer and separated acid liquid in the lower layer;

[0042] The crude fatty acid oil phase is washed multiple times until the pH of the effluent in the lower layer is 6-7 to obtain washing effluent;

[0043] The crude fatty acid oil phase is filtered and centrifuged to obtain crude fatty acid in the upper layer and centrifugal effluent in the lower layer.

[0044] Further, after the amount of substance of acid remaining in the total process effluent and the amount of substance of acid added in the process for preparing crude fatty acid are obtained, the acid remaining rate in the total process effluent is calculated by the following formula:

[0045] ;

[0046] wherein, represents the acid remaining rate in the total process effluent, represents the amount of substance of acid remaining in the total process effluent, represents the amount of substance of acid added in the process for preparing crude fatty acid.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] The application provides a quantitative calculation method for acid comprehensive utilization rate in a crude fatty acid preparation process. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 is a flowchart of the quantitative calculation method for acid comprehensive utilization rate in the crude fatty acid preparation process provided by the embodiment of the application.

[0050] Figure 2 is a schematic diagram of the acid direction path in the crude fatty acid preparation process provided by the embodiment of the application. DETAILED DESCRIPTION

[0051] The application will be further described below in combination with the drawings, and the following embodiments are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0052] Embodiment 1, as shown in the embodiment, provides a quantitative calculation method for acid comprehensive utilization rate in a crude fatty acid preparation process, comprising: Figure 1 analyzing the acid direction path in the crude fatty acid preparation process, including the amount of substance of the acid consumed in the acidification reaction, the amount of substance of the residual acid in the total process effluent and the amount of substance of the acid used for neutralizing the excess monobasic alkali in the saponification reaction;

[0053] determining the acid value of the prepared crude fatty acid and the raw material soap stock used for preparation by the cold solvent indicator method, and then calculating the amount of substance of the acid consumed in the acidification reaction after obtaining the first determination data;

[0054] determining the strong acid acidity of the total process effluent by the titration method, and then calculating the amount of substance of the residual acid in the total process effluent after obtaining the second determination data; wherein the total process effluent includes all non-oil phase liquids separated in the crude fatty acid preparation process;

[0055] obtaining the amount of substance of the acid added in the crude fatty acid preparation process, and then calculating the amount of substance of the acid used for neutralizing the excess monobasic alkali in the saponification reaction in combination with the amount of substance of the acid consumed in the acidification reaction and the amount of substance of the residual acid in the total process effluent;

[0056] calculating the acid comprehensive utilization rate according to the amount of substance of the acid consumed in the acidification reaction, the amount of substance of the acid used for neutralizing the excess monobasic alkali in the saponification reaction and the amount of substance of the acid added in the crude fatty acid preparation process.

[0057] The application provides a quantitative calculation method for acid comprehensive utilization rate in a crude fatty acid preparation process.

[0058] The embodiment realizes quantitative calculation of acid comprehensive utilization rate by analyzing the acid direction path in the preparation of crude fatty acid process, combining the determination of crude fatty acid and soapstock acid value, and combining the determination of strong acid acidity of total process effluent, which can significantly reduce raw material consumption and salt and acidity in wastewater, and has important significance for improving product yield, controlling production cost and reducing environmental pollution.

[0059] Embodiment 2, based on the same technical concept as embodiment 1, the embodiment provides a quantitative calculation method of acid comprehensive utilization rate in the preparation of crude fatty acid process, which is different from embodiment 1, and the embodiment further specifically limits the following contents:

[0060] The first determination data includes the volume of monovalent alkali consumed in the determination of soapstock acid value, the volume of monovalent alkali consumed in the determination of acid value of crude fatty acid, the molar concentration of monovalent alkali consumed in the determination of acid value of crude fatty acid, the mass of prepared crude fatty acid, the sample mass of crude fatty acid weighed in the determination of acid value of crude fatty acid, the total mass of soapstock added in the preparation of crude fatty acid, and the sample mass of soapstock weighed in the determination of acid value of crude fatty acid.

[0061] The second determination data includes the volume of monovalent alkali consumed in the determination of strong acid acidity of total process effluent, the molar concentration of monovalent alkali consumed in the determination of strong acid acidity of total process effluent, the volume of total process effluent, and the volume of effluent taken in the determination of strong acid acidity of total process effluent.

[0062] The monovalent alkali used in the preparation of crude fatty acid is sodium hydroxide, the acid used is sulfuric acid, and the sodium hydroxide used for saponification needs to be excessive, and the sulfuric acid used for acidification needs to be excessive.

[0063] The water content of the raw material soapstock used in the preparation of crude fatty acid is less than 2%.

[0064] The non-oil phase liquid includes: separation acid liquid, washing effluent and centrifugal effluent;

[0065] The separation acid liquid is obtained by the following method: after the acidification is completed, the product is allowed to stand and separate into layers to obtain the lower layer separation acid liquid, which is denoted as ;

[0066] The washing effluent is obtained by the following method: the upper layer crude fatty acid oil phase obtained after the standing and separation is washed with deionized water for 2-3 times until the pH of the lower layer effluent is 6-7, and the washing effluent is obtained, which is denoted as ;

[0067] The centrifugal effluent is obtained by the following method: the washed crude fatty acid oil phase is centrifuged, and the obtained water is the centrifugal effluent, which is denoted as .

[0068] The amount of substance of the acid neutralizing the excess monovalent alkali in the saponification reaction , calculated by the following equation:

[0069] ;

[0070] wherein, represents the amount of substance of acid used to neutralize the excess monobasic base in the saponification reaction, represents the amount of substance of acid added in the preparation of crude fatty acid, represents the amount of substance of acid consumed in the acidification reaction, represents the amount of substance of acid remaining in the total process effluent.

[0071] The acid comprehensive utilization rate is calculated by the following equation:

[0072] ;

[0073] wherein, represents the acid comprehensive utilization rate, represents the amount of substance of acid used to neutralize the excess monobasic base in the saponification reaction, represents the amount of substance of acid added in the preparation of crude fatty acid, represents the amount of substance of acid consumed in the acidification reaction.

[0074] The amount of substance of acid consumed in the acidification reaction of fatty acid sodium is calculated by the following equation:

[0075] ;

[0076] wherein, represents the amount of substance of acid consumed in the acidification reaction, represents the amount of monobasic base consumed by the acid in the titration unit amount, represents the volume of monobasic base consumed in the determination of the acid value of crude fatty acid, represents the molar concentration of monobasic base consumed in the determination of the acid value of crude fatty acid, represents the mass of crude fatty acid prepared, represents the mass of sample of crude fatty acid weighed in the determination of the acid value of crude fatty acid, represents the volume of monobasic base consumed in the determination of the acid value of soapstock, represents the total mass of soapstock added in the preparation of crude fatty acid, represents the mass of sample of soapstock weighed in the determination of the acid value of soapstock.

[0077] The amount of substance of acid remaining in the total process effluent is calculated by the following equation:

[0078] ;

[0079] Wherein, represents the amount of substance of monobasic base consumed by the acid of titration unit, represents the amount of substance of acid remaining in the total process effluent, represents the volume of monobasic base consumed by the strong acid acidity of the total process effluent, represents the molar concentration of monobasic base consumed by the strong acid acidity of the total process effluent, represents the volume of the total process effluent, represents the volume of effluent taken for the determination of the strong acid acidity of the total process effluent.

[0080] The acid residual rate in the total process effluent is calculated by the following formula:

[0081] ;

[0082] Wherein, represents the acid residual rate in the total process effluent, represents the amount of substance of acid remaining in the total process effluent, represents the amount of substance of acid added in the preparation of crude fatty acid process.

[0083] Example 3, based on the same technical concept as Example 1, this embodiment provides a quantitative calculation method for acid comprehensive utilization rate in the preparation of crude fatty acid process.

[0084] Before calculating the acid comprehensive utilization rate, the crude fatty acid is prepared by the following steps S1 and S2.

[0085] S1, construct a preparation device, assemble a three-necked flask, a condensing device, a water bath and a stirrer.

[0086] After adding the reaction material in the three-necked flask, connect the reflux condensing device and fix it in the water bath, and continuously stir the reaction material at a certain temperature and speed.

[0087] S2, specific preparation process.

[0088] S21, raw material dehydration pretreatment: before feeding, take a certain mass of raw material soapstock (Z0) for preparation, and vacuum dry it to a moisture content of less than 2%.

[0089] S22, add the soapstock (Z0) in the three-necked flask, add deionized water in a certain proportion, and stir to promote the mutual solubility of the raw material and water. Figure 2

[0090] Accurately record the total mass (Z0) of the soapstock (Z0) in the three-necked flask and the volume of deionized water, calculated on a dry basis. The soapstock and water are promoted to dissolve by stirring for 3-5 min. Figure 2 ​​​

[0091] S23, the water bath is heated to a certain temperature, the three-necked flask with the above-mentioned Z0 and water is fixed in the water bath, the reflux condenser is connected, the stirrer is started to stir the material, a sodium hydroxide solution with a certain mass concentration (in this embodiment, 35%, which can also be 25-45%) is added, and saponification is carried out for a period of time (in this embodiment, 60 min, which can also be more than 60 min, but not less than 60 min), and the saponification temperature is stabilized at 80-90°C. Figure 2

[0092] S24, after saponification, a certain mass concentration (in this embodiment, 50%, which can also be 20-80%) of sulfuric acid (which can also be replaced by hydrochloric acid, and in this embodiment, sulfuric acid is used as an example) is added to the reaction container for acidification, the acidification temperature is stabilized at 80-90°C, and the acidification is carried out for a period of time (in this embodiment, 40 min, which can also be more than 40 min, but not less than 40 min).

[0093] The amount of sulfuric acid used is accurately recorded, and the mass concentration is recorded.

[0094] S25, after acidification, the product is moved from the three-necked flask to a separatory vessel, and is allowed to stand and separate into layers to obtain the upper crude fatty acid oil phase and the lower acid liquid, the lower acid liquid is discharged, and the acid liquid is collected and labeled as , the above-mentioned acid liquid is used as the separated acid liquid, and the volume of the separated acid liquid is recorded as .

[0095] S26, the upper crude fatty acid oil phase obtained after standing and separating in step S25 is washed with deionized water for 3 times (in this embodiment, 3 times, which can also be 2-4 times), until the pH of the lower water washing effluent is 6-7, to obtain the water washing effluent, which is labeled as ; the volume of the water washing effluent is accurately recorded as .

[0096] S27, the crude fatty acid oil phase washed in step S26 is filtered using a 200-mesh nylon screen (in this embodiment, 200 mesh, which can also be 200-300 mesh), the impurities in the crude fatty acid oil phase are removed, and the crude fatty acid oil phase is centrifuged at 4000 r / min (which can also be 4000-5000 r / min) for 25 min (in this embodiment, the centrifugation time is 25 min, which can also be 20-30 min), the water and oil are separated again, the mass of the upper crude fatty acid (Z1 in Figure 2 ) is weighed and labeled as m1, and the lower water is the centrifugal effluent , the volume of the centrifugal effluent (Z2 in ) is measured and labeled as .

[0097] S28, the separated acid liquid in steps S25, S26, and S27 is​ Washing water output Centrifugal water output Mixing yields the total effluent from the process. Measure the total effluent from the process. volume .

[0098] .

[0099] After the above preparation process, the comprehensive utilization rate of acid is quantitatively calculated, and the acid destination path is analyzed to obtain the following results: Figure 2 The diagram shows the path of acid.

[0100] like Figure 2 As shown, the sulfuric acid has three possible paths:

[0101] Path 1: Amount of sulfuric acid consumed in the acidification reaction ( Moore); The value was calculated from the sodium hydroxide consumed in the determination of the acid value of crude fatty acids;

[0102] Path 2: Total process effluent The amount of residual acid in the substance ( Moore); From the total effluent of the process The sodium hydroxide consumed in the determination of strong acidity was calculated.

[0103] Path 3: The amount of acid used to neutralize excess sodium hydroxide in the saponification reaction ( Moore); The total amount of sulfuric acid added ( )minus and get( ).

[0104] according to Figure 2 and Figure 1 The following measurements and calculations were performed:

[0105] The acid values ​​of the prepared crude fatty acids and the soapstock used in the preparation were determined according to the cold solvent indicator method in GB 5009.229-2016 "National Food Safety Standard - Determination of Acid Value in Food". The volume of monobasic alkali consumed in determining the acid value of the soapstock was obtained. The volume of monobasic base consumed in determining the acid value of crude fatty acids. The molar concentration of the monobasic base consumed in determining the acid value of crude fatty acids. The quality of the crude fatty acids obtained Determining the acid value of crude fatty acids: Weigh the sample of crude fatty acids. The total mass of soapstock added during the preparation of crude fatty acids The mass of soapstock sample weighed for determining the acid value of soapstock. Then, calculate the amount of acid consumed in the sodium fatty acid acidification reaction. The monobasic base is sodium hydroxide.

[0106] The sodium hydroxide titration solution consumed in determining the acid value of crude fatty acids was prepared according to the requirements of GB / T 601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents", and its concentration was standardized with potassium hydrogen phthalate, denoted as . .

[0107] Calculate the amount of acid consumed in the acidification reaction. It can be done using the following formula:

[0108] ;

[0109] in, This indicates the amount of monobasic base required to titrate one unit amount of acid. In this example, since the acid is sulfuric acid, therefore... The value of is 2.

[0110] The total effluent from the process was measured using two testing standards: "Chemical Reagents: General Methods for Determination of Acidity and Alkalinity (GB / T 9736-2008)" and "Methods for Monitoring and Analysis of Water and Wastewater, Fourth Edition". The volume of monobasic alkali consumed to determine the strong acidity of the total effluent from the process is obtained by measuring the strong acidity. The molar concentration of monobasic alkali consumed to determine the strong acidity of the total effluent from the process is determined. Total effluent volume of the process The volume of effluent separated from the total effluent from the process was determined by measuring the strong acidity. Then, calculate the amount of residual acid in the total effluent from the process. The monobasic base is sodium hydroxide.

[0111] The sodium hydroxide titration solution consumed for determining the strong acidity of the total effluent from the process was prepared according to the requirements of GB / T 601-2016 "Preparation of Standard Titration Solutions for Chemical Reagents", and its concentration was standardized with potassium hydrogen phthalate, denoted as . .

[0112] Calculate the amount of residual acid in the total effluent from the process. It can be done using the following formula:

[0113] .

[0114] according to , and The amount of substance of the acid used to neutralize the excess monobasic alkali in the saponification reaction , by the following formula:

[0115] .

[0116] According to , and , the acid comprehensive utilization rate is calculated by the following formula:

[0117] ;

[0118] wherein, represents the acid comprehensive utilization rate.

[0119] The acid residual rate in the total process effluent is also calculated by the following formula:

[0120] ;

[0121] wherein, represents the acid residual rate in the total process effluent.

[0122] In this embodiment, the above method is repeated twice, which are referred to as Experiment 1 and Experiment 2, respectively. The data required to be recorded during the experiment and the determination results are shown in Table 1:

[0123] Table 1-Experimental data table

[0124]

[0125] According to the data in Table 1, the amount of substance of sulfuric acid consumed in the acidification reaction is calculated to be 0.0066 mol (Experiment 1) and 0.0054 mol (Experiment 2), respectively.

[0126] According to the data in Table 1, the amount of substance of the acid remaining in the total process effluent is calculated to be 0.0023 mol (Experiment 1) and 0.0015 mol (Experiment 2), respectively.

[0127] According to the above data, the comprehensive utilization rate of sulfuric acid is calculated to be 95.4% (Experiment 1) and 96.9% (Experiment 2), respectively; and the residual rate of sulfuric acid is calculated to be 4.6% (Experiment 1) and 3.1% (Experiment 2), respectively.

[0128] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should also be considered as the protection scope of the present application.​​

Claims

1. A method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids, characterized in that, include: The analysis included the fate of acids during the preparation of crude fatty acids, including the amount of acid consumed in the acidification reaction, the amount of acid remaining in the total effluent from the process, and the amount of acid used to neutralize excess monobasic base in the saponification reaction. The acid values ​​of the prepared crude fatty acids and the raw soapstock used in the preparation were determined by the cold solvent indicator method. After obtaining the first set of measurement data, the amount of acid consumed in the acidification reaction was calculated. The acidity of the strong acid in the total effluent of the process was determined by titration. After obtaining the second measurement data, the amount of residual acid in the total effluent of the process was calculated. The total effluent of the process includes all non-oil phase liquids separated during the preparation of crude fatty acids. After obtaining the amount of acid added during the preparation of crude fatty acids, the amount of acid used to neutralize the excess monobasic base in the saponification reaction is calculated by combining the amount of acid consumed in the acidification reaction and the amount of acid remaining in the total effluent of the process. The comprehensive utilization rate of acid is calculated based on the amount of acid consumed in the acidification reaction, the amount of acid used to neutralize excess monobasic base in the saponification reaction, and the amount of acid added during the preparation of crude fatty acids. The first set of measurement data includes the volume of monobasic base consumed in determining the acid value of soapstock, the volume of monobasic base consumed in determining the acid value of crude fatty acid, the molar concentration of monobasic base consumed in determining the acid value of crude fatty acid, the mass of crude fatty acid obtained, the mass of crude fatty acid sample weighed for determining the acid value of crude fatty acid, the total mass of soapstock added in preparing crude fatty acid, and the mass of soapstock sample weighed for determining the acid value of soapstock. The amount of acid consumed in the acidification reaction is calculated using the following formula: ； in, This indicates the amount of acid consumed in the acidification reaction. This indicates the amount of monobasic base required to titrate one unit amount of acid. This indicates the volume of monobasic base consumed in determining the acid value of crude fatty acids. This indicates the molar concentration of the monobasic base consumed in determining the acid value of crude fatty acids. This indicates the mass of the crude fatty acid obtained. This indicates the mass of the crude fatty acid sample weighed for determining the acid value of crude fatty acids. This indicates the volume of monobasic base consumed in determining the acid value of soapstock. This indicates the total mass of soapstock added in the preparation of crude fatty acids. This indicates the mass of the soapstock sample weighed for determining the acid value of the soapstock. The non-oil phase liquid includes: separation acid, washing effluent, and centrifugation effluent.

2. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 1, characterized in that, The second set of measurement data includes the volume of monobasic alkali consumed to determine the strong acidity of the total effluent from the process, the molar concentration of the monobasic alkali consumed to determine the strong acidity of the total effluent from the process, the volume of the total effluent from the process, and the volume of effluent separated to determine the strong acidity of the total effluent from the process.

3. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 2, characterized in that, The separated acid solution is obtained by the following method: after acidification, the product is allowed to stand and separate into layers to obtain the lower layer of separated acid solution, denoted as... ; The washing effluent is obtained by the following method: The upper crude fatty acid oil phase obtained after the settling and stratification process is washed repeatedly with deionized water until the pH of the lower effluent reaches 6-7, thus obtaining the washing effluent, denoted as […]. ; The centrifuged effluent is obtained by the following method: the washed crude fatty acid oil phase is centrifuged, and the resulting water is the centrifuged effluent, denoted as _____. .

4. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 1, characterized in that, After obtaining the amount of acid added during the preparation of crude fatty acids, the amount of acid used to neutralize the excess monobasic base in the saponification reaction is calculated by combining the amount of acid consumed in the acidification reaction and the amount of acid remaining in the total effluent of the process, using the following formula: ； in, This indicates the amount of acid used to neutralize excess monobasic base in the saponification reaction. This indicates the amount of acid added during the preparation of crude fatty acids. This indicates the amount of acid consumed in the acidification reaction. This indicates the amount of acidic substances remaining in the total effluent from the process.

5. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 1, characterized in that, The comprehensive acid utilization rate is calculated based on the amount of acid consumed in the acidification reaction, the amount of acid used to neutralize excess monobasic base in the saponification reaction, and the amount of acid added during the preparation of crude fatty acids, using the following formula: ； in, Indicates the comprehensive utilization rate of acid. This indicates the amount of acid used to neutralize excess monobasic base in the saponification reaction. This indicates the amount of acid added during the preparation of crude fatty acids. This indicates the amount of acid consumed in the acidification reaction.

6. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 1, characterized in that, The amount of residual acid in the total effluent from the process is calculated using the following formula: ； in, This indicates the amount of monobasic base required to titrate one unit amount of acid. This indicates the amount of acidic substances remaining in the total effluent from the process. This indicates the volume of monobasic alkali consumed to determine the strong acidity of the total effluent from the process. This indicates the molar concentration of the monobasic alkali consumed to determine the strong acidity of the total effluent from the process. This indicates the total volume of water discharged from the process. This indicates the volume of effluent taken to measure the strong acidity of the total effluent from the process.

7. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 1, characterized in that, The process for preparing crude fatty acids includes: Dry the soap feet; Add soap residue to the reactor, add deionized water, and stir; Connect the reactor to the reflux condenser, connect the reactor to the stirrer, and subject the reactor to a water bath. Saponification is carried out by adding a monobasic alkali; Acid is added for acidification to obtain an intermediate product; The intermediate product was allowed to stand and separate into layers to obtain an upper crude fatty acid oil phase and a lower separated acid solution. The crude fatty acid oil phase is washed multiple times until the pH of the lower effluent is 6-7, thus obtaining the washing effluent. The crude fatty acid oil phase is filtered and centrifuged to obtain the upper layer of crude fatty acids and the lower layer of centrifuged effluent.

8. The method for quantitatively calculating the comprehensive utilization rate of acid in the preparation of crude fatty acids according to claim 1, characterized in that, After obtaining the amount of residual acid in the total process effluent and the amount of acid added during the preparation of crude fatty acids, the acid residue rate in the total process effluent is calculated using the following formula: ； in, This indicates the acid residue rate in the total effluent from the process. This indicates the amount of acidic substances remaining in the total effluent from the process. This indicates the amount of acid added during the preparation of crude fatty acids.

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