CN104345034A - Method for determining chemical oxygen demand of liquid sample and analyzer - Google Patents
Method for determining chemical oxygen demand of liquid sample and analyzer Download PDFInfo
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- CN104345034A CN104345034A CN201410390635.7A CN201410390635A CN104345034A CN 104345034 A CN104345034 A CN 104345034A CN 201410390635 A CN201410390635 A CN 201410390635A CN 104345034 A CN104345034 A CN 104345034A
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/006—Regulation methods for biological treatment
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/18—Water
- G01N33/1806—Water biological or chemical oxygen demand (BOD or COD)
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/001—Upstream control, i.e. monitoring for predictive control
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/005—Processes using a programmable logic controller [PLC]
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/08—Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/11—Turbidity
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/29—Chlorine compounds
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
- G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/333—Ion-selective electrodes or membranes
Abstract
The invention relates to a method for determining the chemical oxygen demand of a liquid sample and an analyzer. The invention describes a method for determining the chemical oxygen demand of a liquid sample by means of an automatic analyzer. The method comprises: -adding a predetermined amount of a reagent to the liquid sample for masking chloride or for the separation of chloride from the liquid sample; -then determining the chemical oxygen demand of the liquid sample; and characterized in that an evaluation and control device of the analyzer determines the predetermined amount of the reagent based on at least one of a chloride content of the liquid sample representing the measured value. The invention also describes an analyzer for carrying out the method.
Description
Technical field
The present invention relates to method and the analyser of the chemical oxygen demand (COD) for automatically determining liquor sample.
Background technology
Chemical oxygen demand (COD), being called for short CSB (English: chemicaloxygendemand, COD) is show as oxygen equivalent
the amount of compound (being generally strong oxidizer), its oxidable composition be comprised in the volume of the determination of liquor sample under the reaction conditions of the method for regulation consumed.At this, potassium dichromate (K
2cr
2o
7) through being commonly used for oxygenant, potassium permanganate (KMnO
4) be also admissible.CSB value is for especially having the running water of organic contaminant and carrying out the important parameter of dustiness classification when wastewater treatment and purification.
For determining in the large multi-method of chemical oxygen demand (COD), liquor sample processes with known excessive use oxygenant method, and the residue that the consumption of oxygenant subsequently is not such as consumed by residual titration is understood fully.The oxidant content consumed is scaled oxygen amount of equal value.
By the method for the known a kind of CSB value for automatically determining liquor sample of prior art.The automatic mode of the CSB value being used for luminosity determination liquor sample is such as described in German patent application DE 103 60 066 A1, wherein, when pressure seal, chemical ware (having by liquor sample and the reaction mixture that formed as the potassium dichromate of strong oxidizer) is heated to above the temperature of the air boiling temperature of reaction mixture within period resolving time (Aufschlusszeit) wherein.Meanwhile, at Period of Decomposition, in chemical ware, determine the absorbance of reaction mixture at least one determination wavelength.Absorbance change is used as the measurement for the oxidant concentration change in reaction mixture.
Chlorion in reaction mixture can disturb the determination of the chemical oxygen demand (COD) of carrying out according to the method.Based on this reason, add mercuric sulfate (II) (Quecksilber (II)-Sulfat) (HgSO to reaction mixture
4), in order to shelter the chlorion in liquor sample.But mercury (II) salt (Quecksilber (II)-Salze) is hypertoxic, the reaction mixture therefore processed by this way must be sent back in water-flow circuit processedly.In other words, it must carry out clearing up and/or preparing with high cost with expending.In addition, because the run duration at automatic analysis system needs higher mercury (II) salt amount, so can there is the harm to operating personnel and environment.
Therefore, German patent application DE 10 2,009 028 165 A1 proposes a kind of method of the CSB value for determining liquor sample by automatic analysis system, wherein, liquor sample first mixed with sulfuric acid, to make the chlorion existed in liquor sample discharge as hydrogen chloride gas before being increased oxygenant.For this reason, guiding carrying gas (such as air) liquor sample by mixing with sulfuric acid, thus hydrogen chloride gas can be realized substantially to discharge completely from liquor sample.In order to determine CSB value, potassium dichromate being joined and removes in muriatic liquor sample, and through the presetting duration, the reaction mixture formed in the above described manner being especially heated to boiling temperature in backflow situation.Be similar to the method that describes in DE 103 60 066 A1 such, by the determination that luminosity determination reaction mixture carries out CSB value for the absorbance of presetting wavelength or absorbance log.
According to the method described in DE 103 60 066 A1, in order to realize sheltering chloride quantitatively by mercury (II) salt, excessively mercury salt must be increased compared with the chloride content be present in liquor sample.According to the method described in DE 10 2,009 028 165 A1, in order to make chloride discharge quantitatively as hydrogen chloride gas, also excessively sulfuric acid must be increased.Because the chloride content in liquor sample is usually unknown, and often also fluctuated at the run duration of automatic analysis system, so automatic analysis system is usually designed to, liquid sample add corresponding for separating of or many reagent of scheduled volume of sheltering, namely, mercury (II) salt or sulfuric acid, thus guarantee, reagent many times excessively exists compared with the non-known chloride content of liquor sample.But this is expensive, and especially additionally unfavorable to environment in the method using mercury (II) salt, and the health of operating personnel may be damaged.At full automation in the analyser that works, the reagent of corresponding use must leave in tank in advance, therefore also when regularly excessively dosage reactant shorten the service intervals of analyser.
Summary of the invention
Therefore, task of the present invention is the method and apparatus proposing to avoid above-mentioned shortcoming.Task is solved by method according to claim 1 and analyser according to claim 7.
Method according to the chemical oxygen demand (COD) for determining liquor sample by automatic analyzer of the present invention comprises the steps:
-increase the reagent of scheduled volume to liquor sample, in order to shelter chloride or to be separated from liquor sample by chloride;
-determine the chemical oxygen demand (COD) of liquor sample subsequently;
Wherein, the scheduled volume of reagent understood fully by the assessment of analyser and control device by the measured value that at least one represents the chloride content of liquor sample.
The reagent being added to liquor sample in order to shelter chloride can be such as mercury (II) salt, such as HgSO
4, it preferably exists in solution.Such as acid can be used as the reagent of separating chlorine from liquor sample, this acid is applicable to make chloride discharge liquor sample as hydrogen chloride gas by displacement reaction.For this reason, e.g. particularly concentrated sulfuric acid is suitable.When calculating the reagent of scheduled volume, assessment and control device preferably consider the volume of liquor sample and the concentration of reagent.
For this reason, the assessment of analyser and control device understand fully the reagent of scheduled volume to be increased by the measured value of the actual chloride content of reflection liquor sample, and assessment and control device can make the corresponding coupling demand of amount of reagent to be increased.Therefore not only avoid excessive dosage reagent and it also avoid very few dosage reagent.This causes cost to decline and extends the maintenance period of the analyser automatically worked, this is because only must upgrade reagent stock in less number of times ground.When reagent is mercury (II) salt, the environmental pressure caused by analyser and health hazard reduce to minimum.
According to the determination treating the amount increasing liquid sample, the assessment of analyser and control device also can control reagent the increasing to liquor sample of scheduled volume.For this reason, assessment and control device such as can with the transport of analyser and dosing mechanism collaborate.Collaborate especially can realize as follows, that is, assessment and control device control at least one pump of transport and dosing mechanism, and this pump controls reagent to the transmission in the container including liquor sample.Container can be such as include the reaction vessels of liquor sample or the liquid line of direct fluids sample.
To the chemical oxygen demand (COD) of liquor sample really usual practice as comprised the steps:
-increase oxygenant to liquor sample, in order to forming reactions potpourri;
-described reaction mixture is heated to the boiling temperature of reaction mixture, especially in backflow situation, through the presetting duration (being also referred to as the resolving time);
-detection represents the measuring-signal of the content of the oxygenant in reaction mixture; With
-understand fully the chemical oxygen demand (COD) of liquor sample thus.
Potassium dichromate or potassium permanganate such as can be used as oxygenant.
Such as by photometering sensor or electrochemical sensor, the measuring-signal of the content such as concentration of the oxygenant represented in reaction mixture can be obtained especially by residual titration.Determine to be undertaken by photometering sensor to the luminosity of oxygenate content, photometering sensor comprises at least one light source and optical receiver, and wherein, the illumination of being launched by light source is penetrated through reaction mixture, and receive by optical receiver.Optical receiver exports the electric measurement signal depending on the intensity of received light.By the signal exported by optical receiver, and when with reference to when increasing the known oxidant content of liquid sample, assessment and control device by the consumption of the oxygenant in the calculation criterion determination reaction mixture can implemented by assessment and control device, and can understand fully the chemical oxygen demand (COD) of liquor sample thus.In like fashion, can automatic analyzer be utilized, automatically perform all method steps mentioned by assessment and control device.
The measuring-signal representing the chloride content of liquor sample can be determined by the chloride sensor being especially designed to ion-selective electrode (ISE).The measuring-signal relevant with measured value can be outputted to assessment and control device by this chloride sensor, in order to further process, especially determines the chloride content of liquor sample, and determines to increase the reagent to the scheduled volume of sample.
Chloride sensor such as (such as in pond, pipeline or groove) can detect the measured value representing the chloride content of liquor sample in sampled point, from sampled point, gather liquid to be studied, from this liquid, extract liquor sample in order to determine CSB value.Can use sample extraction equipment to extract liquid to be studied from sampled point, it especially comprises pump, and liquid transporting is gone out sampled point by pump, and is transferred to and attaches troops to a unit in the sample sample (Probenvorlage) of analyser.
Sample sample can be arranged in the outside of analyser, or integrated ground is arranged in analyser.The transport that automatic analyzer can have been mentioned by it and dosing mechanism extract liquor sample from sample sample.Replace directly measuring chloride content in sampled point, chloride sensor also can detect the measured value representing the chloride content of liquor sample in the external sample sample being arranged in analyser outside.
In order to detect the measuring-signal (chloride sensor detects the chloride content of the liquid be present in sampled point) at the chloride sensor of analyser disposed outside in sampled point, assessment can be connected with chloride sensor with control device, in order to the standard interface transmission of signal by process measurement technology, standard interface such as goes for the measuring-signal that test format is 4..20mA signal.Such as also can realize by fieldbus and/or by process dominates computing machine (Prozessleitrechner) at chloride sensor and the connection between assessment and control device.
As an alternative also possible that, chloride sensor comprises in the vessel of liquor sample at analyser, in inner sample sample, liquid line or reaction vessel, especially detect the measured value representing the chloride content of liquor sample.Analyser such as can have reaction vessel, and in a first step, the liquor sample extracted from sample sample is transferred in this reaction vessel, and increases in the second step for sheltering or the reagent of separating chlorine compound.In the flexible program of method described herein, chloride sensor can detect the chloride content of the liquor sample be included in reaction vessel.
In the first method flexible program, assessment and control device can use the measured value of chloride content that detected before increasing reagent by chloride sensor, that represent liquor sample, thus understand fully the amount of reagent for sheltering completely or needed for separating chlorine compound, and the dosage of control analysis instrument and conveying arrangement, increase understood fully amount of reagent once as follows.
In the method flexible program of alternative, assessment and control device can detect multiple measured value representing the chloride content of liquor sample during increasing reagent, and by detected measured value, especially control increasing of reagent by measurement variation.This flexible program can advantageously be applied in the case where there, namely, chloride by increase sulfuric acid and if desired carried gas blowout and discharge from liquor sample, and chloride sensor is during increasing reagent, the such as chloride content of tracer liquid sample in reaction vessels, in this reaction vessels, liquid mixes with reagent.
In the Advantageous variants scheme of method, wherein, chloride by increase sulfuric acid and if desired carried gas blowout and discharge from liquor sample, assessment and control device detect multiple measured value representing the chloride content of liquor sample successively, and increasing by the corresponding adjustment sulfuric acid of detected measured value.
Assessment and control device can be designed for and automatically perform previously described method step and method flexible program, especially with transport and dosing mechanism, for determining especially photometering sensor and the chloride sensor collaborate of the consumption of oxygenant.For this reason, assessment and control device can have the calculation element and one or more storer that especially comprise one or more processor, calculation element addressable memory, and store the computer program can implemented by calculation element in memory, computer program is for performing relevant method step.Computer program such as can comprise measured value for providing by the especially photometering sensor by the consumption for determining oxygenant to calculate CSB value, and for the algorithm of the reagent of determining the scheduled volume being added to liquor sample.In addition, control or regulate the computer program of transport and dosing mechanism to may be used for performing previously described method step.
The present invention also comprises chemical oxygen demand (COD) for automatically determining liquor sample, in particular for performing the analyser of the method flexible program of previously described method and/or description.This analyser comprises:
-transport and dosing mechanism, its be designed for transport and dosing liquids sample, and for increase to liquor sample scheduled volume for the reagent sheltering chloride or be separated from liquor sample by chloride; With
-assessment and control device, it is designed for and controls transport and dosing mechanism, and determines the chemical oxygen demand (COD) of liquor sample, and described transport and dosing mechanism are used for transport and dosing liquids sample, and for increasing the reagent of scheduled volume to liquor sample,
Wherein, assessment and control device are designed for the scheduled volume that reagent understood fully by the measured value representing the chloride content of liquor sample by least one.
Analyser can also comprise:
-reaction vessel, it has for making oxygenant enter liquor sample so that the liquid gatherer of forming reactions potpourri, wherein, assessment and control device are designed for and control transport and dosing mechanism, and transport and dosing mechanism are used for increasing the oxygenant of scheduled volume so that forming reactions potpourri to liquor sample;
-temperature equipment, in order to heating and/or reaction mixture;
-sensor, especially photometering sensor, it is designed for the measuring-signal producing and represent the oxygenate content of reaction mixture;
Wherein, the measuring-signal that assessment and control device are designed for by especially photometering sensor understands fully chemical oxygen demand (COD).
Being designed for and producing the sensor representing the measuring-signal of the oxygenate content of reaction mixture can be such as photometering sensor, its have at least one along measuring route irradiate through reaction mixture light source and at least one is for detecting the optical receiver of the intensity of the light through measuring route launched by light source.As an alternative, sensor also can be electrochemical sensor, and it is for determining the oxygenate content in reaction mixture by residual titration method.By the content of the oxygenant in reaction mixture, after the presetting resolving time, amount according to increasing the oxygenant of liquid sample in order to forming reactions potpourri can determine oxidant consumption, and can determine the chemical oxygen demand (COD) of liquor sample by oxidant consumption.
For the gatherer of liquor sample with enter into reaction vessel respectively for the gatherer of the reagent increased to liquor sample.In this design proposal, reagent is added to the liquor sample be pre-stored in reaction vessel.For situation sulfuric acid being used as reagent, reaction vessel can have at least one respectively for carrying the gatherer of gas and at least one is for carrying the let-off gear(stand) of gas, they are arranged in such a way, namely, carrying gas is made to flow through the liquor sample be included in reaction vessel, to discharge the hydrogen chloride gas formed owing to increasing sulfuric acid to liquor sample.
Temperature equipment can comprise heater element and be arranged in reaction vessel with the cooling device in the isolated region of heater element, to add thermal reaction mixture under can be implemented in boiling temperature in backflow situation.
In addition, analyser can comprise the chloride sensor being especially designed to ion-selective electrode, and chloride sensor is for detecting the measured value of the chloride content representing liquor sample.Chloride sensor can be connected with assessment and control device, to transmit data, chloride sensor especially can be designed for and the measuring-signal relevant with measured value is passed to assessment and control device, to be further processed.
In order to detect the measured value of the chloride content representing liquor sample, chloride sensor such as can be arranged in sample point, such as, in pond, pipeline or groove, gathers liquid to be studied from sampled point, liquor sample is extracted, in order to determine CSB value from this liquid.
Analyser can be designed for the extracting liq sample from external sample sample by dosage and conveying arrangement.In this design proposal, chloride sensor can be arranged in this sample sample, is included in the measured value of the chloride content of the liquid in sample sample in order to detect representative.
As an alternative, chloride sensor also can be arranged in analyser inside, what be such as arranged in analyser comprises in the vessel of liquor sample, especially in inner sample sample, liquid line or reaction vessel, to detect the measured value representing the chloride content of liquid.
Chloride sensor can be connected with the assessment of analyser and control device, in order to exchange, provide the measuring-signal relevant with measured value with control device to assessment.
In the design proposal of alternative, analyser also can be connected with the chloride sensor not belonging to analyser itself, and chloride sensor such as can be arranged in sampled point, in order to detect the chloride content of the liquid be present in sampled point.In this case, assessment can have can being connected with chloride sensor thus the standard interface of transmission of signal of process measurement technology with control device, the measuring-signal of standard interface can be such as the form being applicable to chlorine detection compound sensor be 4..20mA signal.Also can realize by fieldbus and/or by process dominates computing machine at chloride sensor and the connection between assessment and control device.
Accompanying drawing explanation
Below, the present invention is elaborated by the embodiment illustrated in the drawings.Wherein:
Fig. 1 schematically shows for utilizing chloride sensor to determine the first example of the automatic analyzer of the chemical oxygen demand (COD) of liquor sample, and chloride sensor is for detecting the measured value of the chloride content representing liquor sample;
Fig. 2 schematically shows for utilizing chloride sensor to determine the second example of the automatic analyzer of the chemical oxygen demand (COD) of liquor sample, and chloride sensor is for detecting the measured value of the chloride content representing liquor sample.
Embodiment
Fig. 1 schematically shows the first example of the automatic analyzer 1 for determining chemical oxygen demand (COD).Analyser 1 has reaction vessels 3 and transports and dosing mechanism 5, and transport and dosing mechanism are used for liquor sample and other different matter transportation and are metered in reaction vessels 3.In addition, analyser has multiple tank 7,9,11, comprises liquid to be studied and be added to the reagent of liquid in these tanks.With the sample extraction equipment 13 of analyser 1 collaborate for extracting liquid 15 to be studied from sampled point 17 (such as groove, pond or pipeline).Analyser 1 comprises assessment and control device 19, in order to automatically to perform the determination of the chemical oxygen demand (COD) of the sample extracted from sampled point 17 to liquid 15.
Assessment and control device 19 are data processing equipments, and it such as comprises the calculation element and one or more data and/or program storage with one or more processor, and processor may have access to data and/or program storage.In data and/or program storage, store the computer program can implemented by calculation element, computer program is used for control analysis instrument 1, thus performs the method for the chemical oxygen demand (COD) for determining liquor sample.Assessment and control device 19 comprise and can realize by the display device of operating personnel's Operations Analyst instrument 1 and input equipment.
Sample extraction equipment 13 comprises the pump 21 being such as designed to peristaltic pump or peristaltic pump, and it is by the first tank 7 of being inserted into liquid line 23 in sampled point 17 and being transferred to by liquid 15 to be studied as the inside sample sample of analyser 1.Pump 21 can be connected with the assessment for transmitting data and order and control device 19, thus assessment and control device 19 can control or regulate from the fluid transport sampled point 17 to the first tank 7.In the embodiment of alternative, sample extraction equipment 13 also can have oneself, with assessment and the control part that separates of control device 19.
First tank 7 is connected with the liquid line 25 of transport and dosing mechanism 5, and liquid line 25 enters into reaction vessels 3.The pump 27 being such as designed to syringe pump or peristaltic pump of transport and dosing mechanism 5 is for being transferred to liquid reaction vessels 3 from the first tank 7 by liquid line 25.Assessment is connected with pump 27 with control device 19, to control the amount of liquid determined to be metered in reaction vessels 3 as liquor sample.
Second tank 9 comprises for sheltering the chloride be included in liquor sample, or is added to the reagent of liquor sample for the chloride be included in liquor sample is cleared out of liquor sample.At this, relate to concentrated sulfuric acid in this example.In the design proposal of alternative, reagent also can be mercury (II) salt, such as HgSO
4, it is present in the solution of the second tank 9.Second tank 9 is connected with the liquid line 29 of transport and dosing mechanism 5, and liquid line 29 enters into reaction vessels 3.Such as be designed to the pump 31 of syringe pump or peristaltic pump for being transferred to reaction vessels 3 from the second tank 9 by reagent by liquid line 29.Assessment is connected with pump 31 with control device 19, to control the dosage of carrying out the amount of reagent be transferred in reaction vessels 3.
3rd tank 11 comprises oxygenant, in this example, relates at this potassium dichromate existed in solution.Tank 11 is connected with reaction vessels 3 with another liquid line 39 of dosing mechanism 5 by transport.Such as be designed to the pump 41 of syringe pump or peristaltic pump for transmitting oxygenant by liquid line 39.Pump 41 is connected with assessment and control device 19, and it is for controlling the dosage of carrying out the oxygenant be transferred in reaction vessel 3.
Reaction vessels 3 is designed to be the glassware of cylinder shape substantially in this example, and it has the liquids and gases interface 32 be connected with T-valve 33 in lower zone.By T-valve 33, reaction vessels can optionally with for being connected carrying the gas interface 35 that gas imports in reaction vessels 3, or to be connected with other containers 43 being used as waste container.In the 3rd position of T-valve, reaction vessel can cut out relative to gas interface 35 and container 43 simultaneously.In addition, gas discharge outlet 37 enters into the upper area of reaction vessels 3.
Firing equipment 45 is arranged in the lower zone of reaction vessels 3, and when equipment runs, liquor sample or the reaction mixture formed by liquor sample and oxygenant are present in this lower zone.Cooling device 47 is arranged in the upper area of reaction vessels 3, is especially arranged in following region, even if that is, this region is also arranged in when equipment runs above the liquid level of reaction vessels 3, and is arranged in the region of gas discharge outlet 37.Cooling and firing equipment 47 such as can comprise Peltier's element.But heating and/or cooling effect also by air or liquid register or can realize by heat pipe.
Analyser 1 also comprises photometering sensor 49, and it has light source 51 and optical receiver 53.Light source 51 such as can comprise one or more LED.Optical receiver 53 comprises at least one photodiode.The photo-irradiation reaction vessel 3 launched by light source 51 and the liquid be included in reaction vessels, and be mapped on optical receiver 53.The measuring-signal (especially comprise and measure electric current or measuring voltage) produced according to the light intensity be mapped on optical receiver by optical receiver is strengthened by the metering circuit (not having shown in Figure 1) of photometering sensor 49 in this example if desired, and converts the digital signal flowing to assessment and control device 19 to.
In addition, analyser 1 comprises chloride sensor 55, and it is designed to ion-selective electrode (ISE) in this example.Chloride sensor 55 is for determining the measured value of the chloride content representing current liquid sample.For this object, chloride sensor is inserted in the liquid 15 being present in sampled point 17 place.Chloride sensor 55 comprises measurement converter, and it comprises ion-selective membrane in this case, and this ion-selective membrane is configured with the electromotive force of the chloride content depending on the liquid 15 contacted with ion-selective membrane.That is chloride sensor design is for generation of depending on the electric measurement signal with the chloride content of the liquid 15 of chloride sensor contacts.This electric measurement signal is strengthened and digitizing by the metering circuit of attaching troops to a unit in chloride sensor if desired.Digital signal flows to assessment and control device 19, assessment and control device can process this digital signal further, especially determine sheltering or the amount of reagent needed for chloride in separating liquid sample, liquor sample is extracted from the container 7 being used as sample sample by analyser 1.
Below, describe for for by the automatic analyzer shown in Fig. 1 to determine the example of the method flow of the CSB value of liquor sample:
First, by assessment and control device 19 presetting, the liquid volume come from as the first tank 7 of sample sample is transferred in reaction vessel by liquid line 25 by pump 27 as liquor sample.By the measuring-signal that at least one is provided by chloride sensor 55, at the volume of reference fluids sample with when being included in the concentration of the reagent solution in the second tank 9, assessment and control device 19 understand fully reagent solution for complete from the volume the liquor sample being pre-stored in reaction vessel 3 needed for separating chlorine compound.In this example, reagent solution is concentrated sulfuric acid.The volume of the reagent solution calculated is transported to reaction vessels 3 from the second tank 9 by liquid line 29 by pump 31 by assessment and control device 19.By concentrated sulfuric acid being added to the liquor sample of chloride, because displacement reaction forms hydrogen chloride, it leaves liquor sample as gas.In order to remove hydrogen chloride gas completely, liquor sample is passed through in guiding carrying gas (such as air).For this reason, reaction vessels 3 is connected with gas leading-in device 35 by T-valve 33, and carrying gas (being air in this example) is incorporated in reaction vessels by this gas leading-in device.The carrying gas mixed with hydrogen chloride is derived again by gas discharge outlet 37 from reaction vessels 3.At this, in order to avoid the volatile organic compound matter of liquor sample being discharged from reaction vessels, carrying gas can cool by cooling device 47 in the region of gas discharge outlet 37.
By liquid gatherer 39, the potassium bichromate solution being used as oxygenant is imported the muriatic liquor sample mixed with sulfuric acid of the removal be vented in the above described manner from the 3rd tank 11 by pump 41 in the next step.Preferably by making potassium bichromate solution in sulfuric acid 3g to 120g potassium dichromate being dissolved into one liter of 10% to 30% concentration.Potassium bichromate solution can comprise silver sulfate extraly.By firing equipment 45, the reaction mixture formed in the above described manner is heated to boiling temperature (in atmospheric pressure namely about 150 DEG C), and for the presetting resolving time (Aufschlusszeit), hot plate in backflow situation by cooling device 47.Resolving time is 15 to 120 minutes according to specimen types.
After the presetting resolving time terminates, following measured value is understood fully, the content that the representative of this measured value retains potassium dichromate in the reactive mixture and/or the amount of potassium dichromate consumed when being contained in liquor sample oxidable especially organic substance in oxidation package by photometering sensor 49.The amount of the chromium (III) formed when can understand fully the amount of reservation chromium in the reactive mixture (VI) for this object or understand fully the oxidizable species be contained in oxidation package in liquor sample.Chromium (VI) has maximum absorption when about 430nm.For determining that the suitable wavelength of chromium (VI) content in reaction mixture should be 390nm to 490nm mutually.Chromium (III) has maximum absorption when about 610nm.Corresponding suitable wavelength for chromium (III) content determining reaction mixture is corresponding between 560nm to 660nm.The wavelength that corresponding selection launched by light source is carried out according to the chromium (VI) whether can determined in reaction mixture or chromium (III).
The intensity being emitted through the beam of reaction mixture of the light source 51 detected by optical receiver 53, assessment and control device 19 are determined to consume corresponding to the chromium (VI) showing as oxygen equivalent of the CSB value of liquor sample according to the known method based on Lamber-Beer's Law in the prior art.
After determining CSB value, reaction vessels 3 is by emptying by liquid outlet 32 and the connection of waste container 43 by T-valve 33.
Schematically show the second example of analyser 100 in fig. 2.Analyser 100 builds substantially identically with the analyser 1 described by Fig. 1.The same design of analyser 1 and analyser 100 be provided with identical Reference numeral with in its functionally identical part.
Be different from analyser 1 ground, although analyser 100 comprises chloride sensor 57 equally, chloride sensor is not inserted in the liquid 15 be included in sampled point 17, but is arranged in the chamber wall of the container 7 of the sample sample as analyser 100.Therefore, there, the chloride concentration of chloride sensor 57 tracer liquid, analyser extracts liquid to be studied from this liquid.The advantage of this layout is: chloride sensor 57 provides the measured value that liquor sample concentration is accurately described, on the contrary, the chloride sensor 55 of the analyser 1 shown in Fig. 1 detects the current chloride concentration be present in sampled point.The chloride content of the liquid 15 especially in sampled point fluctuates, the chloride concentration be present in sampled point is not necessarily consistent with the chloride content of the liquid in the sample sample being present in analyser.Therefore, although the measured value detected by chloride sensor 55 represents the chloride content of the liquor sample extracted from sample sample by analyser substantially, but the layout of the chloride sensor 57 of the analyser 100 shown in Fig. 2 can realize the chloride content determining liquor sample more accurately, and therefore more accurately dosage be added to the reagent of liquor sample for removing or shelter chloride.
By the analyser 100 shown in Fig. 2 carry out for determining that the method for liquor sample CSB value is almost identical in before by the description of the analyser 1 shown in Fig. 1.
As beginning has clearly demonstrated, other flexible program of the present invention has also been feasible.Such as, as an alternative, chloride sensor also can be arranged in the inside of reaction vessels 3 and detect the chloride content being included in liquor sample in reaction vessels.At this, during reagent is added to liquor sample, assessment and control device can detect multiple measured value representing the chloride content of liquor sample, and by detected measured value, especially control by measurement variation increasing reagent or regulate.
Claims (11)
1., for determining the method for the chemical oxygen demand (COD) of liquor sample by automatic analyzer (1,100), described method comprises:
-increase the reagent of scheduled volume to liquor sample, in order to shelter chloride or to be separated from liquor sample by chloride;
-determine the chemical oxygen demand (COD) of liquor sample subsequently;
It is characterized in that, the assessment of described analyser and control device (19) understand fully the scheduled volume of reagent by the measured value that at least one represents the chloride content of liquor sample.
2. method according to claim 1,
Wherein, the assessment of described analyser and reagent the increasing to liquor sample of control device (19) control scheduled volume.
3. method according to claim 1 and 2,
Wherein, the determination of the chemical oxygen demand (COD) of liquor sample is comprised:
-increase oxygenant to liquor sample, in order to forming reactions potpourri;
-described reaction mixture is heated to the boiling temperature of reaction mixture, especially in backflow situation, through the presetting time period;
-detection represents the content of the oxygenant in reaction mixture, the especially measuring-signal of the concentration of oxygenant; With
-understand fully the chemical oxygen demand (COD) of liquor sample thus.
4. according to the method in any one of claims 1 to 3,
Wherein, the measuring-signal representing the chloride content of liquor sample, by chloride sensor (55,57), is especially determined by the chloride electrode being designed to ion-selective electrode (ISE).
5. method according to claim 4,
Wherein, described chloride sensor (55) therefrom extracts in the sampled point (17) of liquor sample at described automatic analyzer (1), such as in pond, pipeline or groove, or in the external sample sample of described analyser, detect the measured value representing the chloride content of liquor sample.
6. method according to claim 4,
Wherein, described chloride sensor (57), in the vessel (7) comprising liquor sample of described analyser (100), especially detects the measured value representing the chloride content of liquor sample in inner sample sample, liquid line or reaction vessel.
7., for automatically determining the analyser (1,100) of the chemical oxygen demand (COD) of liquor sample, described analyser comprises:
-transport and dosing mechanism (5), described transport and dosing mechanism be designed for transport and dosing liquids sample, and for increase to liquor sample scheduled volume for the reagent sheltering chloride or be separated from liquor sample by chloride; With
-assessment and control device (19), described assessment and control device are designed for and control described transport and dosing mechanism (5) to transport with dosing liquids sample and to increase the reagent of scheduled volume to liquor sample, and described assessment and control device are designed for the chemical oxygen demand (COD) determining liquor sample
Wherein, described assessment and control device (19) are designed for the scheduled volume that reagent understood fully by the measured value representing the chloride content of liquor sample by least one.
8. analyser according to claim 7 (1,100), it also comprises:
-reaction vessel (3), described reaction vessel has for making oxygenant enter liquor sample so that the liquid gatherer of forming reactions potpourri, wherein, described assessment and control device (19) are designed for and control described transport and dosing mechanism (5), to increase the oxygenant of scheduled volume to liquor sample so that forming reactions potpourri;
-temperature equipment (45,47), in order to heat and/or to cool described reaction mixture;
-sensor (49), especially photometering sensor, described sensor design is for generation of the measuring-signal of oxygenate content representing described reaction mixture;
Wherein, described assessment and control device (19) are designed for and understand fully chemical oxygen demand (COD) by sensor (49), the especially measuring-signal of photometering sensor.
9. analyser according to claim 8 (1,100),
Wherein, for the gatherer (25) of liquor sample with enter into described reaction vessel (3) respectively for the gatherer (29) of the reagent added to liquor sample.
10. analyser (1) according to claim 8 or claim 9,
Described analyser also comprises the chloride sensor (55) being especially designed to ion-selective electrode, described chloride sensor is in order to detect the measured value of the chloride content representing liquor sample and be arranged in described automatic analyzer and therefrom extract in the sampled point (17) of liquor sample, such as in pond, pipeline or groove, or be arranged in the external sample sample of described analyser (1), and described chloride sensor design is used for measuring-signal to output to described assessment and control device (19).
11. analysers (100) according to claim 8 or claim 9,
Described analyser also comprises the chloride sensor (57) being especially designed to ion-selective electrode, described chloride sensor is arranged in the vessel (7) comprising liquor sample of described analyser (100), especially in inner sample sample, liquid line or reaction vessel, and described chloride sensor design is used for measuring-signal to output to described assessment and control device (19).
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| Application Number | Priority Date | Filing Date | Title |
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| DE102013108556.3A DE102013108556A1 (en) | 2013-08-08 | 2013-08-08 | Method and analyzer for determining the chemical oxygen demand of a fluid sample |
| DE102013108556.3 | 2013-08-08 |
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| CN104345034A true CN104345034A (en) | 2015-02-11 |
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| CN104614486A (en) * | 2013-11-05 | 2015-05-13 | 东亚Dkk株式会社 | Automatic apparatus for measuring chemical oxygen demand (cod) |
| CN105445413A (en) * | 2015-12-04 | 2016-03-30 | 江阴秋毫检测有限公司 | Determination method for chemical oxygen demand in water and wastewater |
| CN106198851A (en) * | 2015-04-30 | 2016-12-07 | 张林森 | Full-automatic titration type chemical examination machine and full-automatic titration method thereof |
| CN107782673A (en) * | 2017-11-21 | 2018-03-09 | 苏州市苏测检测技术有限公司 | Food quality detection sample quantifies fast inspection equipment |
| CN109061041A (en) * | 2018-06-15 | 2018-12-21 | 深圳市深投环保科技有限公司 | The measuring method of the COD of waste water |
| CN110967383A (en) * | 2019-12-12 | 2020-04-07 | 北京沅瀚环境科技有限公司 | Electrochemical method for measuring surface water COD |
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| CN109975225B (en) * | 2019-04-17 | 2024-01-02 | 水利部交通运输部国家能源局南京水利科学研究院 | Water quality total phosphorus online analyzer and detection method thereof |
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| CN104614486A (en) * | 2013-11-05 | 2015-05-13 | 东亚Dkk株式会社 | Automatic apparatus for measuring chemical oxygen demand (cod) |
| CN106198851A (en) * | 2015-04-30 | 2016-12-07 | 张林森 | Full-automatic titration type chemical examination machine and full-automatic titration method thereof |
| CN105445413A (en) * | 2015-12-04 | 2016-03-30 | 江阴秋毫检测有限公司 | Determination method for chemical oxygen demand in water and wastewater |
| CN107782673A (en) * | 2017-11-21 | 2018-03-09 | 苏州市苏测检测技术有限公司 | Food quality detection sample quantifies fast inspection equipment |
| CN109061041A (en) * | 2018-06-15 | 2018-12-21 | 深圳市深投环保科技有限公司 | The measuring method of the COD of waste water |
| CN112394031A (en) * | 2019-08-19 | 2021-02-23 | 恩德莱斯和豪瑟尔分析仪表两合公司 | Measuring device for measuring total nitrogen binding in a measurement liquid |
| CN110967383A (en) * | 2019-12-12 | 2020-04-07 | 北京沅瀚环境科技有限公司 | Electrochemical method for measuring surface water COD |
| CN110967383B (en) * | 2019-12-12 | 2022-10-04 | 北京沅瀚环境科技有限公司 | Electrochemical method for measuring surface water COD |
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| DE102013108556A1 (en) | 2015-02-12 |
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