CN210037594U

CN210037594U - Quick detection device of PTA and polyurethane waste water solubility COD of petrochemical industry

Info

Publication number: CN210037594U
Application number: CN201920185515.1U
Authority: CN
Inventors: 王栋; 黄宝华; 季民; 孙力平; 王少坡; 于静洁
Original assignee: Tianjin Chengjian University
Current assignee: Tianjin Chengjian University
Priority date: 2019-02-01
Filing date: 2019-02-01
Publication date: 2020-02-07
Anticipated expiration: 2029-02-01

Abstract

The utility model discloses a petrochemical industry PTA and polyurethane waste water solubility COD short-term test device. The device comprises a PTA wastewater pretreatment assembly connected with an ultraviolet spectrophotometer, wherein the PTA wastewater pretreatment assembly mainly comprises a PTA wastewater sample injector, a dilution tank and a membrane assembly; PTA waste water injector is from getting into after the fixed volume sample of PTA waste water pipeline automatic sampling through six-way valve and batcher intercepting dilution pond, dilute the bottom of the pool and filter the back through 0.45 mu m membrane module, get into online ultraviolet-visible spectrophotometer sample cell, through ultraviolet spectrophotometer examines the utility model discloses the realization is compared conventional COD detection method to the quick test of PTA waste water solubility COD, and COD detection time cost that can significantly reduce practices thrift COD test reagent cost greatly, can eliminate COD simultaneously and detect and cause environmental pollution, has high economy and environmental benefit.

Description

Quick detection device of PTA and polyurethane waste water solubility COD of petrochemical industry

Technical Field

The utility model belongs to the technical field of sewage detection, concretely relates to petrochemical industry PTA and polyurethane waste water solubility COD short-term test device.

Background

At present, the COD detection of PTA production wastewater in the petrochemical industry generally uses a rapid digestion spectrophotometry (HJ/T399-2007) for analysis, and is used for guiding the debugging and operation management of petrochemical sewage treatment facilities. Although the current conventional COD detection method is accurate in the COD analysis result of the PTA wastewater, the time consumption is long, and generally more than 2 hours are needed. Meanwhile, the COD test agents are mainly potassium dichromate, concentrated sulfuric acid, silver sulfate, mercury sulfate and the like, and the agents are expensive and cause serious pollution to the environment. Therefore, on the premise of ensuring the accuracy of the COD test, how to shorten the COD test time and avoid adding precious metals or heavy metal medicaments is a technical problem to be solved by the COD test at present.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that to current COD detection technology not enough, provide and be applicable to petrochemical industry PTA waste water solubility COD short-term test method. The utility model discloses an analysis PTA waste water ultraviolet spectrum fingerprint characteristic combines statistical analysis to find out PTA characteristic spectrum to establish linear relation with solubility COD. The soluble COD value of the PTA wastewater can be directly obtained by detecting the characteristic spectrum absorbance of the PTA wastewater. The utility model discloses the realization is compared the conventional COD detection method to the short-term test of PTA waste water solubility COD, the COD check-out time cost that can significantly reduce. Meanwhile, the cost of the COD detection reagent can be greatly saved, and the environmental pollution caused by COD detection can be eliminated, so that the method has high application value and economic and environmental benefits.

In order to achieve the above purpose, the utility model adopts the following technical scheme: a rapid detection device for water solubility COD of PTA and polyurethane wastewater in petrochemical industry comprises a PTA wastewater pretreatment component connected with an ultraviolet spectrophotometer, wherein the PTA wastewater pretreatment component mainly comprises a PTA wastewater sample injector, a dilution tank and a membrane component; the PTA wastewater sample injector automatically samples from a PTA wastewater pipeline, a fixed volume sample is intercepted through a six-way valve and a quantitative device and then enters the dilution tank, the bottom of the dilution tank is filtered through a 0.45-micrometer membrane assembly and then enters an online ultraviolet-visible spectrophotometer sample tank, and the sample is detected through the ultraviolet spectrophotometer.

The pH value of the dilution pool is automatically adjusted to be within the range of 6-8 by a pH controller, and the constant volume is fixed to a fixed dilution multiple.

The membrane module adopts PES material.

And the detection result of the ultraviolet spectrophotometer is output by a computer.

The pH controller inputs 0.1M NaOH or HCl solution for pH regulation and control through a NaOH solution metering pump or a HCL solution metering pump.

The dilution times of the water sample after the PTA wastewater is filtered are determined according to the absorbance of the water sample, and the absorbance value of the water sample after dilution is ensured to be between 0.5 and 2.5.

And the zero setting of the ultraviolet spectrophotometer adopts deionized water to set zero.

Principle of utility model

The PTA wastewater mainly contains aromatic acid such as terephthalic acid, p-toluic acid, benzoic acid and the like and acetic acid, and the aromatic acid has obvious absorption in ultraviolet visible spectrum UV220-250 nm. And (3) finding out the wavelength of linear relation between the ultraviolet absorbance of the PTA wastewater and the COD through multiple sampling statistics, and determining the value of the COD by detecting the absorbance value of the PTA wastewater under the ultraviolet wavelength.

Calculating the formula:

COD_Cr(mg/L)＝(a×UV+b)×n

wherein: a. b is the slope and intercept of the curve relating UV characteristic wavelength and COD, and the numerical value is obtained by statistical linear fitting;

UV is the absorbance of the UV wavelength with the highest correlation degree with the COD of the PTA wastewater;

and n is the dilution multiple.

Advantageous effects

The utility model discloses an analysis PTA waste water ultraviolet spectrum fingerprint characteristic combines statistical analysis to find out PTA characteristic spectrum to establish linear relation with solubility COD. The utility model discloses the realization is compared the conventional COD detection method to the short-term test of PTA waste water solubility COD, the COD check-out time cost that can significantly reduce. Meanwhile, the cost of the COD test reagent can be greatly saved, the environmental pollution caused by COD detection can be eliminated, and the method has extremely high economic and environmental benefits.

The utility model discloses it is quick to detect speed, is applicable to very much development PTA waste water COD on-line measuring.

Drawings

FIG. 1 is a structural diagram of an apparatus for on-line detection of soluble COD in PTA wastewater.

FIG. 2 is a linear relationship of COD to UV 230.

Reference numerals: the device comprises a 1-ultraviolet spectrophotometer, a 2-PTA wastewater sample injector, a 3-HCL solution metering pump, a 4-membrane assembly, a 5-PTA wastewater pipeline, a 6-six-way valve, a 7-batcher, an 8-dilution tank, a 9-pH controller, a 10-NaOH solution metering pump, a 11-computer, a 12-blow-down pipe, a 13-peristaltic pump, a 14-deionized water tank and a 15-liquid level controller.

Detailed Description

The present invention will be further described with reference to the following detailed description. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and these equivalents also fall within the scope of the appended claims.

A rapid detection device for water solubility COD of PTA and polyurethane wastewater in petrochemical industry comprises a PTA wastewater pretreatment component connected with an ultraviolet spectrophotometer 1, wherein the PTA wastewater pretreatment component mainly comprises a PTA wastewater sample injector 2, a dilution tank 8 and a membrane component 4; the PTA waste water injector 2 is from getting a sample in PTA waste water pipeline 5 automatically, gets into after intercepting fixed volume sample through six-way valve 6 and quantitative 7 dilution pond 8, the liquid level of dilution pond 8 is controlled through controller 15, dilution pond 8 pumps the deionized water in the deionized water pond 14 through peristaltic pump 13 and dilutes, dilution pond 8 bottom is provided with blow-down pipe 12, empties to in the PTA

waste water pipeline

5, 8 bottoms of dilution pond are filtered through 0.45 mu m membrane module 4 after, get into online ultraviolet-visible spectrophotometer sample cell, pass through ultraviolet spectrophotometer 1 detects, ultraviolet spectrophotometer 1 zeroing adopts the deionized water zeroing, ultraviolet spectrophotometer 1 testing result is exported through computer 11.

PES material is adopted by the 0.45-micron membrane assembly 4. The pH value of the diluting pool 8 is automatically adjusted to be within the range of 6-8 through a pH controller 9, and the constant volume is fixed to a fixed diluting multiple. The pH of the pH controller 9 is adjusted by using 0.1M NaOH or HCl solution, and the solution is input into the dilution tank 8 through a NaOH solution metering pump 10 and a HCL solution metering pump 3. The dilution times of the water sample after the PTA wastewater is filtered are determined according to the absorbance of the water sample, and the absorbance value of the water sample after dilution is ensured to be between 0.5 and 2.5.

The utility model discloses be applied to certain petrochemical industry sewage treatment plant PTA waste water COD short-term test of Tianjin, including following step:

first, establishment of standard curve

(1) Sampling a PTA wastewater sampling point of a petrochemical sewage plant for multiple times, and analyzing the COD of the PTA wastewater by using a rapid digestion spectrophotometry (HJ/T399-2007);

(2) adjusting pH of a PTA wastewater sample to 6-8, removing suspended matters by using a 0.45-micron filter membrane, diluting by 50 times through deionized water, and fixing volume to ensure that UV absorbance is between 0.5 and 2.5. Carrying out ultraviolet and visible light full scanning on the diluted water sample;

(3) through statistical analysis, the correlation between UV230 absorbance and COD is better, and linear fitting is shown in figure 2;

secondly, rapid COD detection of PTA wastewater

(1) The PTA wastewater sampler automatically samples from a PTA wastewater pipeline, and a 1mL sample in volume is intercepted through a six-way valve and a quantifier and then enters a dilution tank;

(2) after the PTA wastewater enters a dilution tank, automatically adjusting the pH value to be within the range of 6-8 by a pH controller, and fixing the volume to a fixed dilution multiple (50 times);

(3) the diluted water sample is filtered by a 0.45 mu m membrane module (PES material, common commercial membrane module) and then enters an online ultraviolet-visible spectrophotometer sample cell, the absorbance value of the diluted sample of PTA wastewater is measured at the ultraviolet characteristic spectrum wavelength of the PTA wastewater, the absorbance value is substituted into a relation curve of absorbance and COD, the relation curve is the COD concentration of the PTA wastewater, and the result is output by a computer (Table 1).

TABLE 1 COD value and quick digestion spectrophotometry COD value of the utility model

TABLE 2 COD value and rapid digestion spectrophotometry COD value of the utility model

COD(mg/L)	Sample No. 6	Sample 7	Sample 8	Sample 9	Sample 10
						The utility model discloses	2370	1850	550	1910	3310
Spectrophotometric method	2480	1790	610	1820	3450
						Relative error (%)	-4.43548	3.351955	-9.83607	4.945055	-4.05797

As can be seen from the above tables 1 and 2, the determination results of the method of the utility model and the national standard rapid digestion spectrophotometry are still relatively consistent, and for PTA wastewater in the petrochemical industry, the relative error of COD is in the range of-10.13% -7.14%. The analysis precision meets the requirements of operation and self-checking of PTA wastewater and sewage treatment facilities in the petrochemical industry.

Although the preferred embodiments of the present invention have been described, the present invention is not limited to the above-mentioned embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many changes and modifications without departing from the spirit and the scope of the present invention, which is defined by the appended claims.

Claims

1. The rapid detection device for the water solubility COD of PTA and polyurethane wastewater in petrochemical industry comprises a PTA wastewater pretreatment component connected with an ultraviolet spectrophotometer, and is characterized in that the PTA wastewater pretreatment component mainly comprises a PTA wastewater sample injector, a dilution tank and a membrane component; the PTA wastewater sample injector automatically samples from a PTA wastewater pipeline, a fixed volume sample is intercepted through a six-way valve and a quantitative device and then enters the dilution tank, the bottom of the dilution tank is filtered through a 0.45-micrometer membrane assembly and then enters an online ultraviolet-visible spectrophotometer sample tank, and the sample is detected through the ultraviolet spectrophotometer.

2. The device for rapidly detecting PTA and COD in waste water solubility of the polyurethane as claimed in claim 1, wherein the pH of the diluting pool is automatically adjusted to 6-8 by a pH controller, and the constant volume is fixed to a fixed dilution ratio.

3. The device for rapidly detecting PTA and polyurethane wastewater solubility COD in accordance with claim 1, wherein the membrane module is made of PES material.

4. The device for rapidly detecting the water solubility COD in the PTA and polyurethane wastewater as in claim 1, wherein the detection result of the ultraviolet spectrophotometer is outputted by a computer.

5. The device for rapidly detecting the water solubility COD in the PTA and polyurethane wastewater in the petrochemical industry according to claim 2, wherein the pH controller is a NaOH solution metering pump or an HCl solution metering pump, and the concentration of the NaOH or HCl solution is 0.1M.

6. The device for rapidly detecting the PTA and COD in the wastewater of the petrochemical industry as claimed in claim 2, wherein the zero setting of the UV spectrophotometer is performed by using deionized water.