阅读说明：本技术 酚氨回收中酚钠含量的测定分析方法 (Method for determining and analyzing sodium phenolate content in phenol ammonia recovery ) 是由 张振亮 夏杰 于 2019-08-07 设计创作，主要内容包括：本发明公开了一种酚氨回收中酚钠含量的测定分析方法,包括以下步骤：取煤气化废水试样20～80mL于分液漏斗中,加入乙醚以萃取煤气化废水试样中的酚,将萃取过酚的煤气化废水试样转入烧杯中,将萃取过酚的煤气化废水试样水浴加热15～20分钟,以除去残余的乙醚；在pH＜1的酸性条件下,煤气化废水试样中的酚钠转化为酚,加入过量的溴,则溴与酚反应生成三溴酚,剩余未反应的溴与碘化钾作用,释放出游离碘,用硫代硫酸钠标准溶液滴定,根据其消耗量,计算出酚钠含量。本发明可为酚氨回收添加氢氧化钠含量除去固定氨与二异丙基醚萃取酚工艺调整指明方向,使酚回收具有更高效率；同时,为煤制天然气工艺废水工艺调整提供了可靠的数据监测。(The invention discloses a method for determining and analyzing the content of sodium phenolate in phenol ammonia recovery, which comprises the following steps: taking 20-80 mL of coal gasification wastewater sample into a separating funnel, adding ether to extract phenol in the coal gasification wastewater sample, transferring the coal gasification wastewater sample with the extracted phenol into a beaker, and heating the coal gasification wastewater sample with the extracted phenol in a water bath for 15-20 minutes to remove residual ether; under the acidic condition that the pH value is less than 1, sodium phenolate in a coal gasification wastewater sample is converted into phenol, excessive bromine is added, the bromine reacts with the phenol to generate tribromophenol, the residual unreacted bromine reacts with potassium iodide to release free iodine, sodium thiosulfate standard solution is used for titration, and the sodium phenolate content is calculated according to the consumption of the sodium phenolate standard solution. The invention can adjust the designated direction for the processes of adding sodium hydroxide content to remove fixed ammonia and extracting phenol by diisopropyl ether for recovering phenol ammonia, so that the phenol recovery has higher efficiency; meanwhile, reliable data monitoring is provided for the process adjustment of the coal-to-natural gas process wastewater.)

1. The method for measuring and analyzing the content of sodium phenolate in the phenol ammonia recovery is characterized by comprising the following steps of:

(1) taking 20-80 mL of coal gasification wastewater sample into a separating funnel, adding ether to extract phenol in the coal gasification wastewater sample, transferring the coal gasification wastewater sample with the extracted phenol into a beaker, and heating the coal gasification wastewater sample with the extracted phenol in a water bath for 15-20 minutes to remove residual ether to form a solution A;

(2) transferring the solution A in the step (1) into a 250mL iodometric flask, adding 8-12 mL (1+1) of sulfuric acid solution, and shaking uniformly to form a solution B;

(3) adding 25mL of bromine standard solution into the solution B obtained in the step (2), sealing the solution B with water, placing the solution B in a dark place for 1 hour, then adding 10mL of potassium iodide solution with the mass fraction of 10%, sealing the solution B with water again, and placing the solution B in the dark place for 10 minutes to form a solution to be detected;

(4) titrating with 0.1mol/L sodium thiosulfate standard titration solution, adding 1mL of 5g/L starch indicator solution when the solution is dripped to be light yellow, continuing to titrate until blue color fades, and recording the volume of the sodium thiosulfate standard titration solution consumed by sample titration;

(5) replacing the coal gasification wastewater sample with distilled water with the same volume as the coal gasification wastewater sample in the step (1) to perform a blank test according to the steps (1) to (4), and recording the volume of the sodium thiosulfate standard titration solution consumed in the blank test;

(6) the content (g/L) of the sodium phenolate in the coal gasification wastewater sample is calculated, and the calculation formula of the content (in terms of the sodium phenolate) of the sodium phenolate in the coal gasification wastewater sample is as follows:

in the formula: c-concentration of sodium thiosulfate standard titration solution, mol/L;

V₀-volume of sodium thiosulfate standard solution consumed for the blank test, mL;

V₁-sample titration consumed volume of sodium thiosulfate standard solution, mL;

v is the volume of the coal gasification wastewater sample, mL;

19.35-sodium phenolate (1/6C)₆H₅Molar mass of ONa), g/mol.

2. The method for determining and analyzing the content of sodium phenolate in the recovered phenol ammonia according to claim 1, characterized in that: in step (2), the pH of the solution B is less than 1.

3. The method for determining and analyzing the content of sodium phenolate in the recovered phenol ammonia according to claim 1, characterized in that: in the step (2), the (1+1) sulfuric acid is a sulfuric acid solution diluted by one volume of concentrated sulfuric acid and one volume of pure water.

4. The method for determining and analyzing the content of sodium phenolate in the recovered phenol ammonia according to claim 1, characterized in that: in the step (3), the concentration of the bromine standard solution is c (KBr-KBrO)₃)＝0.1000mol/L。

5. The method for determining and analyzing the content of sodium phenolate in the recovered phenol ammonia according to claim 1, characterized in that: in step (4), the starch indicator should be added near the end point to prevent adsorption of iodine by starch.

6. The method for determining and analyzing the content of sodium phenolate in the recovered phenol ammonia according to claim 1, characterized in that: in the step (4), when the titration is carried out by using 0.1mol/L sodium thiosulfate standard titration solution, fast titration and slow shaking are required to prevent I₂And (4) loss.

Technical Field

The invention belongs to the technical field of phenol ammonia recovery, and particularly relates to a method for determining and analyzing the content of sodium phenolate in phenol ammonia recovery.

Background

In the natural gas prepared from lignite, the key of the phenol-ammonia recovery technology lies in the extraction of phenolic substances in the coal gasification wastewater, no literature can be found at present for measuring the content of sodium phenolate in the coal gasification wastewater, and the sodium phenolate content in the coal gasification wastewater can be measured, so that the process adjustment of adding the content of sodium hydroxide for removing fixed ammonia and extracting phenol with diisopropyl ether can be pointed out, and the phenol recovery has higher efficiency.

Disclosure of Invention

In view of this, the present invention aims to provide a method for determining and analyzing sodium phenolate content in phenol ammonia recovery, which can add sodium hydroxide content to remove fixed ammonia for phenol ammonia recovery and adjust the designated direction of the phenol extraction process with diisopropyl ether, so that phenol recovery has higher efficiency; meanwhile, reliable data monitoring is provided for the process adjustment of the coal-to-natural gas process wastewater.

In order to achieve the purpose of the invention, the technical scheme is as follows:

the method for measuring and analyzing the content of sodium phenolate in the phenol ammonia recovery comprises the following steps:

(1) taking 20-80 mL of coal gasification wastewater sample into a separating funnel, adding ether to extract phenol in the coal gasification wastewater sample, transferring the coal gasification wastewater sample with the extracted phenol into a beaker, and heating the coal gasification wastewater sample with the extracted phenol in a water bath for 15-20 minutes to remove residual ether to form a solution A;

(2) transferring the solution A in the step (1) into a 250mL iodine measuring flask, adding 9-11 mL sulfuric acid solution, and shaking up to form a solution B;

(3) adding 25mL of bromine standard solution into the solution B obtained in the step (2), sealing the solution B with water, placing the solution B in a dark place for 1 hour, then adding 10mL of potassium iodide solution with the mass fraction of 10%, sealing the solution B with water again, and placing the solution B in the dark place for 10 minutes to form a solution to be detected;

(4) titrating with 0.1mol/L sodium thiosulfate standard titration solution, adding 1mL of 5g/L starch indicator solution when the solution is dripped to be light yellow, continuing to titrate until blue color fades, and recording the volume of the sodium thiosulfate standard titration solution consumed by sample titration;

(5) replacing the coal gasification wastewater sample with distilled water with the same volume as the coal gasification wastewater sample in the step (1) to perform a blank test according to the steps (1) to (4), and recording the volume of the sodium thiosulfate standard titration solution consumed in the blank test;

(6) the content (g/L) of the sodium phenolate in the coal gasification wastewater sample is calculated, and the calculation formula of the content (in terms of the sodium phenolate) of the sodium phenolate in the coal gasification wastewater sample is as follows:

in the formula: c-concentration of sodium thiosulfate standard titration solution, mol/L;

V₀-volume of sodium thiosulfate standard solution consumed for the blank test, mL;

V₁-sample titration consumed volume of sodium thiosulfate standard solution, mL;

v is the volume of the coal gasification wastewater sample, mL;

19.35-sodium phenolate (1/6C)₆H₅Molar mass of ONa), g/mol.

Preferably, in step (2), the pH of the solution B is < 1.

Preferably, in the step (2), the (1+1) sulfuric acid is a sulfuric acid solution diluted by one volume of original concentrated sulfuric acid and one volume of pure water.

Preferably, in step (3), the bromine standard solution has a concentration of c (KBr-KBrO)₃)＝0.1000mol/L。

Preferably, in step (4), the starch indicator should be added near the end point to prevent adsorption of iodine by starch.

Preferably, in step (4), when the titration is carried out by using 0.1mol/L sodium thiosulfate standard titration solution, the titration should be carried out quickly and slowly to prevent I₂And (4) loss.

The determination principle of the invention is as follows: extracting total phenol in the coal gasification wastewater by using ether, adjusting the coal gasification wastewater after the total phenol is extracted to be a strong acid solution with the pH value less than 1 by using sulfuric acid for the residual sodium phenolate, converting the sodium phenolate in a coal gasification wastewater sample into phenol under the acidic condition of the pH value less than 1, then adding an excessive bromine standard solution, reacting bromine and phenol to generate tribromophenol, reacting the residual unreacted bromine and potassium iodide to release free iodine, titrating by using a sodium thiosulfate standard solution, and calculating the content of the sodium phenolate according to the consumption. The main reaction is as follows:

C₆H₅ONa+H⁺＝C₆H₅OH+Na⁺

Br₂+2I^-→I₂+2Br^-

I₂+2Na₂S₂O₃→Na₂S₄O₆+2NaI

the method for determining and analyzing the content of sodium phenolate in the phenol ammonia recovery is verified, and comprises three verification processes of a phenol extraction process, a sodium phenolate conversion process and a phenol and sodium phenolate separation process.

And (3) verifying the phenol extraction process:

preparing a plurality of phenol solutions with known concentrations, extracting with diethyl ether, measuring the content of phenol in the water layer by a bromine amount method, and calculating the separation degree according to the content of phenol in the water layer.

And (3) verifying the conversion rate of sodium phenolate:

preparing a plurality of sodium phenolate solutions with known concentrations, adding sulfuric acid into the prepared solutions, titrating by using a bromine method, and verifying whether the measured value is consistent with the known content.

And (3) verifying the separation process of the phenol-sodium phenolate solution:

preparing a phenol-sodium phenolate aqueous solution with a known concentration, extracting with diethyl ether, determining, and comparing the measurement result with the known content.

The method for determining and analyzing the content of the sodium phenolate in the phenol ammonia recovery is proved to have reliability by phenol extraction verification, sodium phenolate conversion rate verification and phenol-sodium phenolate solution separation process verification. The invention can adjust the designated direction for the processes of adding sodium hydroxide content to remove fixed ammonia and extracting phenol by diisopropyl ether for phenol ammonia recovery, so that the phenol recovery has higher efficiency; meanwhile, reliable data monitoring is provided for the process adjustment of the coal-to-natural gas process wastewater.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a titration correction curve for phenol.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. 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 application.