阅读说明：本技术 一种蒽醌法制取过氧化氢中工作液碱度的连续在线分析设备及其使用方法 (Continuous on-line analysis equipment for alkalinity of working solution in preparation of hydrogen peroxide by anthraquinone process and use method thereof ) 是由 张晓斌 贺江峰 沈冲 夏红勋 李文涛 于 2021-01-08 设计创作，主要内容包括：本发明公开了一种蒽醌法制取过氧化氢中工作液碱度的连续在线分析设备及其使用方法,连续在线分析设备包括萃取柱(1),萃取柱(1)下部连接有工作液进料流量控制阀(2),萃取柱(1)底部连接有在线pH值分析仪(5)和废液定量排出阀(6)；萃取柱(1)上部纯水流量控制阀(3)和废工作液阀(4)。使用方法是(1)建立萃取液pH值与工作液碱度的对应关系曲线；(2)测出萃取液水相的pH值；(3)查对工作液碱度。本发明所述设备及方法,采用pH计测定工作液萃取水相的pH值,反映工作液的真实碱度,可实现工作液碱度的连续在线分析。结果准确可靠,不受人为因素影响,有效降低人员劳动强度,减少员工与工作液的接触。(The invention discloses continuous on-line analysis equipment for alkalinity of working solution in preparation of hydrogen peroxide by an anthraquinone method and a using method thereof, wherein the continuous on-line analysis equipment comprises an extraction column (1), the lower part of the extraction column (1) is connected with a working solution feeding flow control valve (2), and the bottom of the extraction column (1) is connected with an on-line pH value analyzer (5) and a waste liquid quantitative discharge valve (6); a pure water flow control valve (3) and a waste working solution valve (4) on the upper part of the extraction column (1). The use method comprises (1) establishing a corresponding relation curve of the pH value of the extraction liquid and the alkalinity of the working solution; (2) measuring the pH value of the aqueous phase of the extract liquid; (3) checking the alkalinity of the working solution. The equipment and the method adopt the pH meter to measure the pH value of the extraction water phase of the working solution, reflect the real alkalinity of the working solution and realize the continuous on-line analysis of the alkalinity of the working solution. The result is accurate and reliable, is not influenced by human factors, effectively reduces the labor intensity of personnel, and reduces the contact between the personnel and the working solution.)

1. A continuous on-line analysis device for alkalinity of working solution in hydrogen peroxide preparation by anthraquinone process is characterized by comprising an extraction column (1), wherein the lower part of the extraction column (1) is connected with a working solution feeding flow control valve (2), and the bottom of the extraction column (1) is connected with an on-line pH value analyzer (5) and a waste liquid quantitative discharge valve (6); a pure water flow control valve (3) and a waste working solution valve (4) on the upper part of the extraction column (1).

2. The continuous in-line analyzer apparatus of claim 1, wherein a PLC program control module is connected.

3. A method of using the continuous on-line analyzer apparatus of claim 1 or 2, comprising the steps of:

(1) establishing a corresponding relation curve of the pH value of the extraction liquid and the alkalinity of the working solution by the prior art;

(2) leading the working solution after the white soil bed on the production line for preparing hydrogen peroxide by an anthraquinone method into the lower part of an extraction column through a pipeline and then into the extraction column, simultaneously leading pure water into the extraction column from top to bottom, leading the working solution in the extraction column to float upwards by a continuous water phase, forming dispersed phase liquid drops through a filler layer, gradually reaching the top of the extraction column, and discharging the liquid drops to a waste liquid recovery system from an upper overflow port; the working solution and pure water are subjected to countercurrent mass transfer extraction through a packing layer, water-soluble alkali liquor in the extracted working solution is arranged at the bottom of the extraction column, and the pH value of the water phase of the extraction liquid is measured by a pH value analyzer;

(3) and checking the alkalinity of the working solution according to the measured corresponding relation curve of the pH value and the alkalinity.

4. The use method of claim 3, wherein the ratio of the height to the diameter of the extraction column is 100: 1-10.

5. The use of claim 3, wherein the extraction column is packed with wire mesh θ rings.

6. The use method of claim 3, wherein the volume ratio of the working fluid to the pure water is 1: 0.1-1.

Technical Field

The present invention belongs to the field of anthraquinone process of preparing hydrogen peroxide.

Background

The anthraquinone process of preparing hydrogen peroxide uses anthraquinone compound as carrier of working liquid and makes hydrogen and oxygen react under certain condition to produce hydrogen peroxide. The main production processes comprise a hydrogenation process, an oxidation process, an extraction process and a post-treatment process. In order to reduce the content of hydrogen peroxide in the working solution entering the hydrogenation system and ensure the regeneration effect of anthraquinone degradation products in the working solution, the working solution treated by the post-treatment process needs to reach a certain alkalescence.

The alkalinity of a working solution in the traditional anthraquinone method for preparing hydrogen peroxide is analyzed by an acid-base titration method, the analysis frequency is once per hour, and the analysis is carried out by sampling on site manually, wherein the specific method comprises the following steps: taking a certain amount of the working solution behind the clay bed on a manual site, sending the working solution to an analysis laboratory, taking 100ml of the working solution by using a measuring cylinder, injecting the working solution into a separating funnel, adding 20ml of neutral distilled water for extraction, standing for layering, putting the lower-layer aqueous solution into a triangular flask, repeatedly extracting for 5 times in such a way, adding 2-3 drops of a mixed indicator into all the extraction liquid, titrating by using hydrochloric acid with a certain concentration to change the solution from green to wine red as an end point, and calculating the alkalinity of the working solution according to the consumption of the hydrochloric acid, wherein the unit is mg/L.

The method not only needs manual field sampling every hour, and is long in time consumption, but also has a large influence on an analysis result by human factors (extraction times, titration endpoint identification and the like). If the working condition of the device is unstable, the lag of the analysis result cannot meet the process adjustment requirement due to long time consumed for sampling and analyzing.

Some methods adopt a pH value on-line analyzer to measure the pH value of the working solution so as to reflect the pH value of the working solution. In the actual operation process, due to the complex components of the working solution, the pH value measured by the method cannot well reflect the real pH value of the working solution, the discreteness is very large, and the method has no guiding significance on production.

Disclosure of Invention

The invention aims to solve the first technical problem of continuous on-line analysis equipment for alkalinity of working solution in hydrogen peroxide preparation by an anthraquinone process.

The second technical problem to be solved by the invention is a using method of the continuous on-line analysis equipment. The method has the advantages of good safety, high automation degree and strong timeliness, can be used for timely and continuously obtaining the analysis value of the alkalinity of the working solution on line, is free from the influence of human factors on the analysis result, has small system error, effectively reduces the labor intensity of an analyst, and reduces the contact of the analyst and the working solution.

In order to solve the first technical problem, the technical scheme of the invention is as follows: a continuous on-line analysis device for the alkalinity of a working solution in the preparation of hydrogen peroxide by an anthraquinone process comprises an extraction column 1, wherein the lower part of the extraction column 1 is connected with a working solution feeding flow control valve 2, and the bottom of the extraction column 1 is connected with an on-line pH value analyzer 5 and a waste liquid quantitative discharge valve 6; a pure water flow control valve 3 and a waste working solution valve 4 on the upper part of the extraction column 1. The on-line analysis equipment is connected to a production line for preparing hydrogen peroxide by an anthraquinone method, and can be used for continuously monitoring the alkalinity of the working solution.

The continuous on-line analysis equipment is connected with the PLC program control module to realize automatic control.

In order to solve the second technical problem, the invention provides a using method of continuous on-line analysis equipment for alkalinity of a working solution in hydrogen peroxide preparation by an anthraquinone method, which comprises the following steps:

(1) establishing a corresponding relation curve of the pH value of the extraction liquid and the alkalinity of the working solution by the prior art;

(2) leading the working solution after the white soil bed on the production line for preparing hydrogen peroxide by an anthraquinone method into the lower part of an extraction column through a pipeline and then into the extraction column, simultaneously leading pure water into the extraction column from top to bottom, leading the working solution in the extraction column to float upwards by a continuous water phase, forming dispersed phase liquid drops through a filler layer, gradually reaching the top of the extraction column, and discharging the liquid drops to a waste liquid recovery system from an upper overflow port; the working solution and pure water are subjected to countercurrent mass transfer extraction through a packing layer, water-soluble alkali liquor in the extracted working solution is arranged at the bottom of the extraction column, and the pH value of the water phase of the extraction liquid is measured by a pH value analyzer.

(3) And checking the alkalinity of the working solution according to the measured corresponding relation curve of the pH value and the alkalinity.

The height-diameter ratio of the extraction column is generally 100: 1-10, and high-efficiency fillers such as wire mesh theta rings and the like are filled in the extraction column.

The volume ratio of the working liquid to the pure water is generally 1: 0.1-1.

The equipment and the method adopt the pH meter to measure the pH value of the extraction water phase of the working solution, reflect the real alkalinity of the working solution and realize the continuous on-line analysis of the alkalinity of the working solution. The result is accurate and reliable, is not influenced by human factors (extraction times, titration end point identification and the like), effectively reduces the labor intensity of personnel, and reduces the contact between the personnel and the working solution.

Drawings

FIG. 1 is a schematic view of a continuous on-line analytical apparatus according to the present invention.

Wherein: 1. an extraction column; 2.1 as liquid feed flow control valve; 3. a pure water flow control valve;

4. a waste liquid discharge valve; 5. an on-line pH analyzer; 6. and a waste liquid quantitative discharge valve.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

As shown in figure 1, the continuous on-line analysis equipment for the alkalinity of the working solution in the preparation of hydrogen peroxide by the anthraquinone process comprises an extraction column 1, wherein the lower part of the extraction column 1 is connected with a working solution feeding flow control valve 2, and the bottom of the extraction column 1 is connected with an on-line pH value analyzer 5 and a waste liquid quantitative discharge valve 6; a pure water flow control valve 3 and a waste liquid valve 4 on the upper part of the extraction column 1. The continuous on-line analysis equipment is accessed to the PLC program control module.

Potassium carbonate solutions with different concentrations are adopted, the pH value of the potassium carbonate solution is measured, and the alkalinity of the potassium carbonate solution is measured by an off-line method. Because the alkalinity and the pH value are in logarithmic relation, the alkalinity and the pH value are logarithmized to obtain a linear fitting curve, and the unit of the linear fitting curve is 10 along the abscissa Ln (alkalinity)⁶mg/L, ordinate Ln (pH). Ln (alkalinity) is linear with Ln (pH) in this range, and a linear fit curve equation is used: ln (ph) ═ 0.108Ln (alkalinity) +1.914, and linear correlation coefficient R ═ 0.994. The linear fitting curve is used for the continuous monitoring system of the alkalinity of the circulating working solution in the hydrogen peroxide solution process.

Example 1

A hydrogen peroxide model test device is provided with the continuous on-line analysis equipment for the alkalinity of the working solution, the flow of the working solution is controlled to be 100L/h, the working solution enters an extraction column (the height-diameter ratio is 100: 1, and a wire mesh theta ring is efficient filler) from the lower part of the extraction column, and the flow of pure water is controlled to be 10L/h, so that the water-soluble alkali solution in the working solution is extracted.

Sampling is carried out on site by operators every 1 hour, the alkalinity of a sample is measured in a laboratory by an off-line method, the pH value of the sample is measured by an on-site alkalinity on-line analyzer, and the alkalinity of the sample is calculated by a linear fitting curve. The results of the experiment are shown in table 1.

As shown in Table 1, the error between the alkalinity values of the off-line test and the alkalinity calculation values of the linear fitting curves is +/-0.01 mg/L, and the test requirement that the error is less than 0.03mg/L is met.

TABLE 1 comparison of the alkalinity values of the offline test and the linear fit curve

Example 2

A hydrogen peroxide device with the concentration of 10 ten thousand tons per year (27.5%) is provided with the continuous on-line analysis equipment for the alkalinity of the working solution, the flow of the working solution is controlled to be 100L/h, the working solution enters an extraction column (the height-diameter ratio is 10: 1, and a wire mesh theta ring is efficient filler) from the lower part of the extraction column, and the flow of pure water is controlled to be 100L/h, so that water-soluble alkali liquor in the working solution is extracted.

The operator samples the sample on site every 2 hours, the sample is off-line in the laboratory to measure the alkalinity, and simultaneously, the on-site alkalinity on-line analyzer is adopted to measure the pH value, and the linear fitting curve is utilized to calculate the alkalinity. The results of the experiment are shown in table 2.

TABLE 2 comparison of the alkalinity values from off-line testing and linear fit curves

As shown in Table 2, the error between the alkalinity values of the off-line test and the alkalinity calculation values of the linear fitting curves is +/-0.02 mg/L, and the test requirement that the error is less than 0.03mg/L is met.