CN113996078B - Simple processing method for concentrated natural organic acid by using biomass dry distillation acid as raw material - Google Patents

Abstract

A simple processing method of concentrated natural organic acid by using biomass dry distillation acid as a raw material belongs to the field of new natural product separation and purification processing technology and organic food. The method comprises the steps of using biomass dry distillation acid as a raw material, performing low-temperature vacuum distillation, placing in the sun in a ventilating manner to oxidize volatile phenolic substances into compounds such as hydroquinone, quinophthalone and the like which are not easy to volatilize, adding magnesium sulfate monohydrate to absorb water, performing secondary vacuum medium-temperature distillation, and enabling the purity of concentrated acetic acid to reach more than 99.5% and the content of phenol to be less than or equal to 1mg/L. According to the simple processing method for the concentrated natural organic acid by taking the biomass dry distillation acid as the raw material, the prepared product reaches the standard of an organic food additive; meanwhile, the magnesium sulfate is recycled and the energy is recycled, so that the cost is reduced and the energy is saved.

Description

Simple processing method for concentrated natural organic acid by using biomass dry distillation acid as raw material

Technical Field

The invention belongs to the field of new natural product separation and purification processing technology and organic food, and particularly relates to a simple processing method of concentrated natural organic acid by taking biomass dry distillation acid as a raw material.

Background

However, in the history of pollutant development in China, some environments without artificial intervention or with little artificial intervention exist, such as bamboo forests and forests (non-economic forests), the environments are rarely polluted, and the generated photosynthesis products belong to natural products and meet various harsh conditions of organic products.

The bamboo vinegar liquid contains nearly 200 kinds of natural high molecular organic compounds, mainly organic acids, especially 3-9% acetic acid, and secondly 2.0-12.0% tar mainly phenol, guaiacol and other phenol substances, a small amount of alcohols, ketones, aldehydes, esters and the like, and the rest 80-90% water. Bamboo wood vinegar has many functions, but the marketization application is not wide or even limited, and the main reasons are as follows: 1) Although the content of the bamboo-wood vinegar liquid is in a trace level, the content of various foods, food additives and medicines and skin care products requires a trace level on the content of harmful substances, most of the bamboo-wood vinegar liquid requires a mg/kg or even a microgram/kg or ng/kg level, the content of dissolved tar is 1.20-1.50% of refined bamboo vinegar liquid and 0.08-0.10% of distilled bamboo vinegar liquid according to GB/T31734-2015 bamboo vinegar liquid standard, the content of various phenols accounts for more than 50% of tar, the converted standard phenol content requires 400000-7500000 microgram/kg, even the best bamboo-wood vinegar liquid according to the market is 400000 microgram/kg, and the reference to sanitary Standard for Drinking Water (GB 5749-2006) requires the content of volatile phenol to be not more than 2 microgram/kg and is entirely 200000 times, so that the bamboo-wood vinegar liquid can not reach the edible standard, and obviously can not reach the standard beyond the standard; 2) Bamboo wood vinegar has unpleasant odor, which is easy to cause the dislike of consumers; in a word, the technology for removing harmful substances such as phenols and the like from the bamboo vinegar liquid determines whether the application of the bamboo vinegar liquid can be expanded and the bamboo vinegar liquid can be safely used. Patent ZL201910027997.2 a method for dewatering, concentrating and separating tar of planting vinegar, the drier is directly added in bamboo wood vinegar stock solution in the first step, like this have a large amount of phenolic substances to get into the product, have to use again and plant a large amount of organic solvent that vinegar mass fraction 1-20 times, not only increase cost, because organic solvent uses and has inevitably some organic solvents to get into the final product, influence the product quality, the problem that the distillation process volatile phenol gets into the final product is not considered in its process, and the complicated energy consumption of technology is big, under the goal that carbon reaches peak and carbon neutralizes, difficult effective production, simultaneously because of using organic solvent in a large number, whether the product can still have certain problem as organic product.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to design and provide a technical scheme for a simple processing method of concentrated natural organic acid by using biomass dry distillation acid as a raw material, firstly distilling bamboo wood vinegar liquid, firstly removing more than 99% of phenolic substances in the first step, only a small amount of volatile phenolic substances enter distillate, converting the small amount of residual volatile phenol into other substances without volatility under the condition of natural light oxidation in the second step, and mixing the substances with magnesium sulfate during the second distillation to achieve the aim of removing more than 98% of volatile phenol. The method has the advantages of simple process and energy recycling, the whole production process is carried out in a natural environment, the production only has a physical process and does not have a man-made chemical process, the requirements of organic products on production, processing, identification and management systems are completely met according to the requirements of GB/T19630-2019 organic products, the production cost is low, the processing method is simple and environment-friendly, the high-valued utilization of wastes is realized, and certain contribution is made to carbon peak reaching and carbon neutralization.

The simple processing method for concentrating the natural organic acid by taking the biomass dry distillation acid as the raw material is characterized by comprising the following steps of:

1) Adopting biomass dry distillation acid as a raw material, carrying out primary distillation at the low temperature of 38-45 ℃ and the vacuum degree of-0.090 MPa to-0.097 MPa, and collecting distillate;

2) Placing the distillate in a transparent sealed container with volume 2-3 times of the distillate, standing at normal temperature in the presence of sunlight for 15-30 days, opening the sealing member every day, shaking for 1-1.5 min, and closing the sealing member until the color is not deepened to obtain a standby distillate;

3) Putting magnesium sulfate monohydrate into a distillation container, adding standby distillate under the condition of closed stirring at 25-35 r/min, wherein the mass ratio of each standby distillate to the magnesium sulfate monohydrate is 1.15-1.27;

4) High temperature 48-58 deg.C, vacuum degree of-0.090 MPa to-0.097 MPa, distilling for the second time till it is complete, collecting distillate, i.e. concentrated natural organic acid, and making solid be magnesium sulfate heptahydrate crystal;

5) The magnesium sulfate heptahydrate crystals are converted into magnesium sulfate monohydrate in hot air at 150-210 ℃ through a rotary flash evaporation dryer, the magnesium sulfate monohydrate is recycled in the step 3), and hot steam is recycled in the step 1) and the step 4) as a distillation heat source.

The simple processing method for concentrating natural organic acid by taking biomass dry distillation acid as a raw material is characterized by comprising the following steps of 1): the temperature is 40-42 ℃, and the vacuum degree is-0.093 MPa to-0.095 MPa.

The simple processing method for concentrating the natural organic acid by taking the biomass dry distillation acid as the raw material is characterized in that in the step 2): the distillate of the first distillation is placed until the color is not deepened, namely, the absorbance of the distillate is measured at the wavelength of 560-600nm by using a spectrophotometer with distilled water as a reference and a cuvette with a 10mm optical path, and the absorbance is not increased obviously.

The simple processing method for concentrating the natural organic acid by taking the biomass dry distillation acid as the raw material is characterized in that in the step 3): the mass ratio of each part of the standby distillate to the magnesium sulfate monohydrate is 1.2-1.25 parts.

The simple processing method for concentrating the natural organic acid by taking the biomass dry distillation acid as the raw material is characterized in that in the step 4): the temperature is 50-54 ℃, and the vacuum degree is-0.094 MPa to-0.095 MPa.

The simple processing method for concentrating the natural organic acid by taking the biomass dry distillation acid as the raw material is characterized in that in the step 5): the drying temperature is 170-190 ℃.

The biomass dry distillation acid meets the condition of organic input products, namely that bamboo, wood and crop straws which are used as raw materials for firing the biochar are non-transgenic biomass, and chemical fertilizer and chemical pesticide application management is not applied, namely the biochar raw materials are organic raw materials.

The invention provides a simple processing method for concentrating natural organic acid by taking biomass dry distillation acid as a raw material, which has the following innovation points:

1) The invention can concentrate the biomass dry distillation acid with the organic acid content of 1-10% to the organic acid content of more than 98%;

2) No organic solvent is used, so that the product pollution and the environmental pollution are reduced, and the cost is greatly reduced;

3) The adopted physical process has no chemical reaction process, and is suitable for the requirements of organic products;

4) The first distillation adopts low-temperature distillation, so that the content of volatile phenol and homologues thereof is greatly reduced, and more than 99% of phenol substances in biomass dry distillation acid can be removed in the process;

5) The second step is to stand in the sun for 15-30 days at normal temperature, so that volatile phenols in the distillation process mainly comprise phenol and guaiacol, and are converted into benzoquinone hydroquinone, benzoquinone hydroquinone and other compounds with larger molecular weight and no volatility through illumination oxidation, medium temperature distillation is adopted in the second distillation, the content of phenolic homologues in distillate is further reduced, and more than 98% of volatile phenol substances can be removed in the process.

6) The magnesium sulfate monohydrate is a heat release process when distilled biomass dry distillation acid is added, and secondary distillation is immediately carried out after the magnesium sulfate monohydrate is added, so that heat supply is reduced, and energy is saved; magnesium sulfate heptahydrate is converted into magnesium sulfate monohydrate to provide a heat source, water vapor with the temperature of six water molecules raised to 150 ℃ returns to the heat source for 2 times of distillation for recycling, so that the condition that extra energy is not required for 2 times of distillation is ensured, and energy is greatly saved.

7) Magnesium sulfate heptahydrate is converted into magnesium sulfate monohydrate for recycling, so that the influence of impurities in the magnesium sulfate is reduced, and the production cost is greatly saved;

8) The raw material of the product is organic biomass raw material, the produced final product is a natural product with high value, and the aim of high-value utilization of waste is fulfilled.

Drawings

FIG. 1 is a technical flow chart of the present invention.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying drawings and detailed description, in which it is to be understood that the embodiments described are merely illustrative of some, but not all embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Weighing 100 kg bamboo vinegar, placing in vacuum distillation equipment, distilling at low temperature of 38 deg.C and vacuum degree of-0.097 MPa, placing distillate in 200L transparent plastic bucket in sunlight, opening cover, shaking for 1 min every day, observing color deepening process every day until color deepening is not reached any more (with distilled water as reference, absorbance OD580nm measured by a cuvette with optical path of 10mm at 580nm wavelength is less than 5% by spectrophotometer, OD580nm =0.735 at 16 days, OD580nm =0.745 at 17 days, its change value is (0.745-0.735)/0.735 x 100% =1.4% < 5%), and keeping the liquid for use; weighing 115kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring for 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 48 ℃ and the vacuum degree of-0.097 MPa until the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 150 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

Example 2

Weighing 100 kg of pyroligneous liquor, loading into a vacuum distillation device, carrying out first distillation at a low temperature of 40 ℃ and a vacuum degree of-0.095 MPa, putting distillate into a 200L transparent plastic barrel, placing the barrel in the sunlight, opening a cover every day, shaking for 1 minute, observing the color deepening and changing process every day until the color is not deepened any more in the 20 th day, and keeping the liquid for later use; weighing 120kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring at 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 51 ℃ and the vacuum degree of-0.095 MPa until the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 160 ℃, and recycling the magnesium sulfate monohydrate, wherein hot steam is generated for energy utilization of the 2 times of distillation.

Example 3

Weighing 100 kg of straw vinegar, filling the straw vinegar into a vacuum distillation device, carrying out primary distillation at the low temperature of 45 ℃ and the vacuum degree of-0.090 MPa, putting distillate into a 200L transparent plastic barrel, placing the barrel in the sunlight, opening a cover every day, shaking for 1 minute, observing the color deepening and changing process every day until the color is not deepened any more in 25 days, and keeping the liquid for later use; weighing 127kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring at 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 58 ℃ and the vacuum degree of-0.090 MPa till the standby liquid is completely stirred, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 170 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

Example 4

Weighing 50 kg of bamboo vinegar and 50 kg of wood vinegar, putting into a vacuum distillation device, distilling at low temperature of 42 ℃ and vacuum degree of-0.094 MPa for the first time, putting distillate into a 200L light-transmitting plastic barrel, placing in the sun, opening a cover and shaking for 1 minute every day, observing the color deepening process every day until the color is not deepened any more in the 30 th day, and keeping the liquid for later use; weighing 125kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring at 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 55 ℃ and the vacuum degree of-0.092 MPa till the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 180 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

Example 5

Weighing 60 kg of bamboo vinegar liquid and 40 kg of straw vinegar liquid, filling the bamboo vinegar liquid and the straw vinegar liquid into a vacuum distillation device, carrying out primary distillation at the low temperature of 43 ℃ and the vacuum degree of-0.093 MPa, putting distillate into a 200L transparent plastic barrel, placing the barrel in the sunlight, opening a cover to shake for 1 minute every day, observing the color deepening change process every day until the color is not deepened any more on the 19 th day, and reserving the liquid; weighing 122kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring for 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 53 ℃ and the vacuum degree of-0.096 MPa until the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 190 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

Example 6

Weighing 35 kg of wood vinegar and 65 kg of straw vinegar, loading into a vacuum distillation device, distilling at a low temperature of 44 ℃ and a vacuum degree of-0.094 MPa for the first time, putting distillate into a 200L transparent plastic barrel, placing in the sun, opening a cover every day, shaking for 1 minute, observing the color deepening change process every day until the color is not deepened any more on day 21, and keeping the liquid for later use; weighing 116kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring for 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 54 ℃ and the vacuum degree of-0.093 MPa until the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 200 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

Example 7

Weighing 30 kg of bamboo vinegar, 45 kg of wood vinegar and 25kg of straw vinegar, filling the bamboo vinegar, the wood vinegar and the straw vinegar into a vacuum distillation device, carrying out primary distillation at the low temperature of 41 ℃ and the vacuum degree of-0.095 MPa, putting distillate into a 200L transparent plastic barrel, placing the barrel in the sun, opening a cover to shake for 1 minute every day, observing the color deepening change process every day until the color is not deepened any more on day 21, and keeping the liquid for later use; weighing 118 kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring for 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 49 ℃ and the vacuum degree of-0.096 MPa until the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 210 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

Example 8

Weighing 10 kg of bamboo vinegar, 70 kg of wood vinegar and 20kg of straw vinegar, filling the bamboo vinegar, the wood vinegar and the straw vinegar into a vacuum distillation device, carrying out primary distillation at the low temperature of 38 ℃ and the vacuum degree of-0.097 MPa, putting distillate into a 200L transparent plastic barrel, placing the barrel in the sun, opening a cover to shake for 1 minute every day, observing the color deepening change process every day until the color is not deepened any more in 30 days, and keeping the liquid for later use; weighing 127kg of magnesium sulfate monohydrate, putting the magnesium sulfate monohydrate into a distillation container, slowly adding the standby liquid under the condition of closed stirring for 30 r/min, uniformly stirring, carrying out secondary distillation at the high temperature of 58 ℃ and the vacuum degree of-0.090 MPa until the magnesium sulfate monohydrate is completely distilled, collecting distillate, namely a final product, converting solid magnesium sulfate heptahydrate into magnesium sulfate monohydrate through a rotary flash evaporation dryer at the temperature of 210 ℃ for recycling, and generating hot steam for energy utilization of the 2 times of distillation.

The content change of the effective components and the harmful components of the calcium acetate and the acetic acid is illustrated by the following experiments, and the experiments refer to a plurality of national standards, and the specific design is as follows: all assays were repeated 3 times for analysis of variance.

1. Method for measuring total organic acid (calculated by acetic acid) content of stock solution and first distillate

According to GB 2719-2018 national food safety standard vinegar and GB/T5009.41-2003 vinegar sanitary standard analysis method, vinegar mainly comprises acetic acid and a small amount of other organic acids, the vinegar is titrated by a sodium hydroxide standard solution, a PH8.2 final point is measured by an acidimeter, and the result is expressed by acetic acid.

10.0mL of sample is taken and placed in a 100mL volumetric flask, water is added to the scale, and the mixture is mixed uniformly. Sucking 20.0mL of the solution, placing the solution in a 200 mL beaker, adding 60 mL of water, and operating according to GB/T5009.39-2003 from 4.2.1.4, starting a magnetic stirrer, 8230, 8230and operating according to the law. And simultaneously, carrying out a reagent blank test. The total acid content (in acetic acid) in the sample was calculated as follows. X = (V1-V2) × c × 0.060/(V × 10/100) × 100, in which: x is the total acid content (in acetic acid) of the sample, wherein the position of 21336is gram per hundred milliliters (g/100 mL), V1 is the volume of the sodium hydroxide standard titration consumed by the sample diluent and the unit is milliliter (mL); v2 reagent blank sodium hydroxide consumption Standard titration solution volume in milliliters (mL); c, the concentration of a sodium hydroxide standard titration solution, wherein the unit is mol per liter (mol/L); 0.060-the mass of acetic acid in grams (g) corresponding to 1.OO mL of sodium hydroxide standard solution [ c (NaOH) = 1.000 mol/L ]; v is sample volume in milliliters (mL).

2. Method for measuring content of total organic acid (calculated by acetic acid) in concentrated solution

With reference to the method of GB1886.10-2015 national standard food additive glacial acetic acid (also known as glacial acetic acid) for food safety, the method is briefly described as follows: weighing 1g of sample, accurately measuring the sample to 0.002g, placing the sample in a 250mL conical bottle with a plug, filling 80mL of newly boiled and cooled water in the conical bottle in advance, adding 2 drops of phenolphthalein indicator solution, titrating the solution by using a sodium hydroxide standard titration solution (NaOH) = 0.5 mol/L) until the solution is in a light pink color, and keeping the end point of the solution unchanged for 30 s.

The mass fraction w1 of the acetic acid content is calculated according to the formula: w1= (V × c × M)/M × 100%, where: v is the volume of the sodium hydroxide standard titration solution in milliliters (mL); c, the concentration of a sodium hydroxide standard titration solution, wherein the unit is mol per liter (mol/L); m is the molar mass of acetic acid in grams per mole (g/mol), [ M (CH 3 COOH) =0.06005; m is the mass of the sample in grams (g).

3. The method for measuring the content of the total phenols comprises the following steps:

according to GB/T7490-1987 determination of water quality volatile phenol and HJ 503-2009 determination of water quality volatile phenol 4-aminoantipyrine spectrophotometry, samples with mass concentration higher than the upper limit of standard determination of 0.04mg/L are diluted appropriately and then determined. The solid was dissolved in distilled water and then measured. The pH of the liquid sample is adjusted by sodium carbonate, the liquid is distilled along with water vapor and can react with 4-aminoantipyrine to generate volatile phenolic compounds of colored compounds, and the result is calculated by phenol. Distilling to remove volatile phenolic compounds, and separating with interfering substances and fixing agent. Since the volatilization rate of the phenolic compound varies depending on the volume of the distillate, the volume of the distillate must be equal to the volume of the sample. Reacting the distilled phenolic compound with 4-aminoantipyrine in a pH (10.0 +/-0.2) medium in the presence of potassium iron amide to generate orange-red antipyrine dye, extracting with chloroform, and measuring the absorbance at 460 nm.

The specific analysis steps are as follows: 1) Pre-distillation: and (3) transferring 250ml of sample into a 500 ml full glass distiller, adding 25ml of water, adding a plurality of glass beads to prevent bumping, adding a plurality of drops of methyl orange indicating liquid, and continuously adding phosphoric acid solution if the sample does not show orange red. Connecting with a condenser, heating and distilling, and collecting 250ml of stuffing liquid into a volumetric flask. During the distillation, if the methyl orange red color is faded, the solution should be cooled after the distillation is finished, and then 1 drop of methyl orange indicator solution is added. If the residual liquid after distillation is not acidic, a sample is sampled again, and the adding amount of the phosphoric acid solution is increased for distillation. Transferring 250ml of stuffing liquid into a separating funnel, adding 2.0 ml of buffer solution, mixing uniformly, adjusting pH value to 10.0 +/-0.2, adding 1.5ml of 4-aminoantipyrine solution, mixing uniformly, adding 1.5ml of iron-dense potassium solution, mixing uniformly, sealing, and standing for 10 min.

2) And (3) extraction: accurately adding 10.0ml of trichloromethane into the color separation funnel, sealing, violently shaking for 2 min, inverting for degassing, and standing for layering. Wiping the inner wall of the neck pipe of the separating funnel with dry absorbent cotton or filter paper, plugging a small group of dry absorbent cotton or filter paper in the neck pipe, leading the chloroform layer to pass through the dry absorbent cotton group or filter paper, discarding a plurality of drops of initially filtered extract liquor, and directly putting the rest chloroform into a cuvette with the optical path of 30 mm.

3) And (3) measuring absorbance: and measuring the absorbance value of the trichloromethane layer at the wavelength of 460 nm by taking trichloromethane as a reference.

4) Blank test: the sample was replaced with water and the absorbance was measured. The blank should be measured simultaneously with the sample.

Subtracting the absorbance value of a zero concentration tube from the absorbance value measured by the calibration series, drawing a curve of the absorbance value to the phenol content, and enabling the correlation coefficient of a regression equation of the calibration curve to reach more than 0.999;

mass concentration of volatile phenol in the sample (in terms of phenol) according to the formulapCalculation of = (As-Ab-a)/(bV) × 1000: in the formula: p-mass concentration of volatile phenol in the sample, mg/L; as: the absorbance value of the sample; ab: absorbance values for the blank test; a: calibrating the intercept value of the curve; b-the slope of the calibration curve; v-volume of sample, mL.

4. Naturalness detection

According to the following: ASTM D6866-2016, the sample is fully combusted in pure oxygen to carbon dioxide, purified to remove nitrogen oxides and sulfur oxides, converted to sodium carbonate aqueous solution, after purging the instrument with pure nitrogen, 40-50% phosphoric acid is added, the generated carbon dioxide is absorbed to the prepared solution by freezing to remove water: in a quantitative mixture of ethylenediamine and scintillation fluid, carbon dioxide and ethylenediamine generate a stable cyclic compound; and weighing to calculate the net weight of the carbon dioxide. The carbon 14 atoms in the sample completely enter carbon dioxide, when the test bottle enters an ultralow background liquid scintillation meter, the carbon 14 atoms decay once, the emitted BETA rays activate the scintillator to emit light once, and the meter records the number of light emission times in unit time. The unit of measure is DPM/g.c (average: 1 minute per gram of carbon, how many times decayed); coal is taken as 0, fresh plants (the current standard value of 13.6DPM/g.C according to ASTM D6866-2016) are taken as 100%, and 95-105% are qualified (12.92-14.28 DPM/g.C). TABLE 1 contents of effective components, harmful substances, etc. and naturalness of natural acetic acids prepared in examples 1 to 8 of example 1

As can be seen from Table 1, the total organic acid (calculated by acetic acid) content in the final product liquid of examples 1-8 is concentrated from 3.6-6.4g/100mL (equivalent to 3.5-6.3%) of the stock solution to 98.5-99.9% and 95.5-99.5% of natural degree, and the total organic acid content meets the requirements of national standard GB1886.10-2015 of 99.5% purity and 95% of natural degree and also meets the international ASTM D6866-2016 standard. The content of the phenols in the liquid after the second distillation is 0.7-1.0mg/L, which is less than or equal to 1mg/L.

The embodiments described in this specification are merely illustrative of implementations of the inventive concepts, which are intended for purposes of illustration only. The scope of the present invention should not be construed as being limited to the particular forms set forth in the embodiments, but is to be accorded the widest scope consistent with the principles and equivalents thereof as contemplated by those skilled in the art.

Claims (5)

1. A simple processing method for concentrating natural organic acid by taking biomass dry distillation acid as a raw material is characterized by comprising the following steps:

1) Adopting biomass dry distillation acid as a raw material, carrying out primary distillation at the low temperature of 38-43 ℃ and the vacuum degree of-0.090 MPa to-0.097 MPa, and collecting distillate;

2) Placing the distillate into a transparent sealed container with 2-3 times volume capacity, standing in the presence of sunlight at normal temperature for 15-30 days, opening the sealing member every day, shaking for 1-1.5 minutes, and closing the sealing member until the color is no longer deepened to obtain a standby distillate; the distillate is placed until the color is not deepened, namely, the absorbance of the distillate is measured by a spectrophotometer by taking distilled water as a reference and a cuvette with the optical path of 10mm at the wavelength of 560-600nm, and the absorbance is not increased obviously any more;

3) Putting magnesium sulfate monohydrate into a distillation container, adding standby distillate under the condition of closed stirring at 25-35 r/min, wherein the mass ratio of each standby distillate is 1.15-1.27 parts of magnesium sulfate monohydrate;

4) High temperature 49-58 deg.C, vacuum degree-0.090 MPa to-0.097 MPa, distilling for the second time till completion, collecting distillate, i.e. concentrated natural organic acid, and making solid be magnesium sulfate heptahydrate crystal;

5) Magnesium sulfate heptahydrate crystals are converted into magnesium sulfate monohydrate through a rotary flash evaporation dryer in hot air at 150-210 ℃, the magnesium sulfate monohydrate is returned to the step 3) for recycling, and hot steam is returned to the step 1) and the step 4) as a distillation heat source for recycling.

2. The method for simply processing concentrated natural organic acid using biomass dry distillation acid as raw material according to claim 1, wherein the step 1) comprises: the temperature is 40-42 ℃, and the vacuum degree is-0.093 MPa to-0.095 MPa.

3. The simple processing method of concentrated natural organic acid using biomass dry distillation acid as raw material according to claim 1, wherein in step 3): the mass proportion of each part of the standby distillate corresponds to 1.2 to 1.25 parts of magnesium sulfate monohydrate.

4. The method for processing concentrated natural organic acid using biomass dry distillation acid as raw material according to claim 1, wherein the step 4) comprises: the temperature is 50-54 ℃, and the vacuum degree is-0.094 MPa to-0.095 MPa.

5. The method for processing concentrated natural organic acid using biomass dry distillation acid as raw material according to claim 1, wherein the step 5) comprises: the drying temperature is 170-190 ℃.

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