WO2015090593A1 - Method for determining the content of organic carbon compounds in mineral acids - Google Patents
Method for determining the content of organic carbon compounds in mineral acids Download PDFInfo
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- WO2015090593A1 WO2015090593A1 PCT/EP2014/003413 EP2014003413W WO2015090593A1 WO 2015090593 A1 WO2015090593 A1 WO 2015090593A1 EP 2014003413 W EP2014003413 W EP 2014003413W WO 2015090593 A1 WO2015090593 A1 WO 2015090593A1
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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
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/004—CO or CO2
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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
- G01N33/02—Food
- G01N33/12—Meat; Fish
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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
- G01N21/84—Systems specially adapted for particular applications
- G01N2021/8411—Application to online plant, process monitoring
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
- G01N21/272—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration for following a reaction, e.g. for determining photometrically a reaction rate (photometric cinetic analysis)
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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
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
- G01N21/35—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light
- G01N21/3504—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infrared light for analysing gases, e.g. multi-gas analysis
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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
- G01N21/84—Systems specially adapted for particular applications
- G01N21/85—Investigating moving fluids or granular solids
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Definitions
- the invention is in the field of production of inorganic precursors and relates to a continuous process for the determination of the content of organic hydrocarbons in mineral acids.
- Hydrochloric acid is an inorganic acid which is obtained by introducing hydrogen chloride gas into water. It is one of the most important inorganic raw materials, which is used in particular for the processing of ores and rock phosphates. Another major area of application is the stimulation of oil and gas probes in both carbonate and sandstone deposits.
- hydrochloric acid as a by-product in the preparation of DI (ethylene diphenyl diisocyanate) and TDI (toluene-2,4-diisocyanate), precursors of polyurethanes, in large quantities.
- TDI is produced by phosgenation of TDA (2,4-diaminotoluene). This gaseous hydrochloric acid is released.
- chlorine is reacted with carbon monoxide over a catalyst.
- pressure is increasing to convert the hydrochloric acid produced during the production of TDI and MDI back into chlorine.
- There are three methods available on the market for this purpose On the one hand the Decon process and on the other two electrochemical processes.
- aqueous hydrochloric acid is supplied to the anode and cathode chambers, which are separated from each other by a diaphragm.
- the chlorine is produced which can be used for the production of phosgene in the recycling cycle.
- Hydrogen is generated at the cathode.
- a second electrochemical process is the hydrochloric acid electrolysis using HCI-ODC technology.
- the anode chamber is fed aqueous hydrochloric acid and the cathode chamber oxygen, both chambers are separated by an ion-conducting membrane.
- the acid is converted to chlorine and the free protons migrate through the membrane to the cathode, the so-called ODC (Oxygen Depolarised Cathode).
- Hydrochloric acid however, depending on the origin of the starting material and quality sometimes contains such high levels of organic compounds that they are without prior purification for further processing, especially for use in the electrochemical chlorine production
- CONFIRMATION COPY not suitable.
- the object of the present invention has thus been to provide an apparatus and a method available that remedies the problems outlined.
- this method should allow atline, on-line, and preferably continuously different, aqueous mineral acids with both high and low nonaqueous fractions to be screened to see if and how much organic carbon compounds they contain.
- the process should be designed in such a way that even TOC amounts in the range of 0.1 mg / l can be detected.
- the invention relates to a method, preferably in continuous operation, for determining the content of organic carbon compounds in mineral acids, in which
- the combustion gases thus obtained are discharged from the combustion chamber and cooled to such an extent that all co-formulants with a dew point below 20 ° C. separate out as liquids,
- the continuous metering of the mineral acids into the combustion chamber and the continuous flow of the sample to the analyzer allow an equally continuous determination of the TOC content as a function of time.
- Suitable mineral acids are hydrofluoric acid (HF), bromic acid (HBr), iodic acid (Hl), hypochlorous acid (HCIO), chloric acid (HCIO3) and perchloric acid (HCIO4).
- HF hydrofluoric acid
- Hl bromic acid
- Hl hypochlorous acid
- HCIO chloric acid
- HCIO4 perchloric acid
- Aqueous mineral acids can be used up to the maximum concentration.
- the mineral acids have an aqueous content of at least about 63% by weight, more preferably from about 65 to about 80, and most preferably from about 70 to about 90% by weight.
- hydrochloric acid for example, solutions having a concentration of up to 37% by weight (HCl) can be used.
- gaseous mineral acids that are free of impurities that interfere with the measurement of carbon dioxide
- a sample preferably a continuous stream of aqueous or gaseous mineral acids is conveyed into a combustion chamber.
- the throughput of mineral acid is preferably from about 10 to about 100 ml / h, in particular from about 20 to about 80 ml / h and particularly preferably from about 30 to about 50 ml / h.
- the dosing is preferably carried out in the sense of a dripping, i. individual drops of aqueous mineral acids enter the combustion chamber and evaporate either immediately or at the latest when they hit a baffle plate.
- the mineral acids whose TOC content is to be determined, are mixed in the combustion chamber with combustion gases, which are injected via a second inlet into the chamber.
- the combustion gases have been previously purified so that they themselves do not contain carbon oxides; it is oxygen, but especially air, which has preferably already been preheated.
- the fuel gases are used in large excess, wherein the volume flows preferably about 20 to about 30 Nl / h.
- the combustion chamber is in the broadest sense an oven in which the heat is radiated through the walls; a flame is not there.
- the chamber is made of ceramic or other material that is suitable to withstand the high temperatures of 500 to 1500 ° C, typically 650 to 750 ° C and is also sufficiently resistant to corrosion of the acidic media.
- Step III Detection
- the thus dried reaction gases are fed to a detector which is capable of analyzing carbon oxides, in particular carbon dioxide.
- the analysis can be carried out spectroscopically or photometrically. Particularly preferred are IR methods, in particular the NDIR detection (Non Dispersive Infared). Alternatively, laser spectroscopic methods or gas chromatography are also possible.
- the calibration of the system can be done by previously measuring gases with a defined carbon content (calibration gases) or using aqueous mineral acids with a defined TOC.
- Another object of the invention is directed to an apparatus for determining the content of organic carbon compounds in aqueous mineral acids, comprising
- a detector connected to the separator and capable of determining the content of carbon oxides in the remaining gas phase.
- Fig. 1 A corresponding device is shown in Fig. 1:
- the fuel gases are purified by a carbon dioxide and an acid absorber and passed into the combustion chamber of the reactor. In these, the aqueous mineral acid is dripped.
- the combustion gases are then passed through a condenser with attached liquid separator and the dried gases are then fed to the analyzer.
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Abstract
Description
VERFAHREN ZUR BESTIMMUNG DES GEHALTES AN ORGANISCHEN KOHLENSTOFFVERBINDUNGEN IN MINERALSÄUREN PROCESS FOR DETERMINING THE CONTENT OF ORGANIC CARBON COMPOUNDS IN MINERAL ACIDS
[0001] GEBIET DER ERFINDUNG FIELD OF THE INVENTION
[0002] Die Erfindung befindet sich auf dem Gebiet der Herstellung von anorganischen Grundstoffen und betrifft ein kontinuierliches Verfahren zur Bestimmung des Gehaltes an organischen Kohlenwasserstoffen in mineralischen Säuren. The invention is in the field of production of inorganic precursors and relates to a continuous process for the determination of the content of organic hydrocarbons in mineral acids.
[0003] STAND DER TECHNIK STATE OF THE ART
[0004] Salzsäure stellt eine anorganische Säure dar, die durch Einleiten von Chlorwasserstoffgas in Wasser gewonnen wird. Es handelt sich dabei um einen der wichtigsten anorganischen Grundstoffe, der insbesondere für die Aufarbeitung von Erzen und Rohphosphaten eingesetzt wird. Ein weiteres großes Anwendungsgebiet ist die Stimulation von Erdöl- und Erdgas-Sonden sowohl in Carbonat- als auch Sandsteinlagerstätten. Hydrochloric acid is an inorganic acid which is obtained by introducing hydrogen chloride gas into water. It is one of the most important inorganic raw materials, which is used in particular for the processing of ores and rock phosphates. Another major area of application is the stimulation of oil and gas probes in both carbonate and sandstone deposits.
[0005] Weiter fällt Salzsäure als Nebenprodukt bei der Herstellung von DI ( ethylen- diphenyldiisocyanat) und TDI (Toluol-2,4-diisocyanat), Vorstufen von Polyurethanen, in großen Mengen an. TDI entsteht durch Phosgenierung von TDA (2,4-Diaminotoluol). Hierbei wird gasförmige Salzsäure freigesetzt. Bei der Herstellung von Phosgen wird Chlor mit Koh- lenmonoxid an einem Katalysator umgesetzt. In der chemischen Industrie wächst der Druck die bei der Herstellung von TDI und MDI entstehende Salzsäure wieder in Chlor umzusetzen. Hierfür stehen auf dem Markt drei Verfahren zu Verfügung. Zum einen der Decon Prozess und zum anderen zwei elektrochemische Verfahren. Bei dem älteren Verfahren wird wässri- ge Salzsäure der Anoden und Kathodenkammer zugeführt, diese sind durch ein Diaphragma voneinander getrennt. An der Anode entsteht dann das Chlor das für die Herstellung von Phosgen im Recyclingkreislauf verwendet werden kann. An der Kathode entsteht Wasserstoff. Ein zweites elektrochemisches Verfahren ist die Elektrolyse von Salzsäure mittels der HCI-ODC Technologie. Hierbei wird der Anodenkammer wässrige Salzsäure zugeführt und der Kathodenkammer Sauerstoff, beide Kammern werden durch eine ionenleitende Membran getrennt. Die Sahsäure wird zu Chlor umgesetzt und die freien Protonen wandern durch die Membran an die Kathode, die sogenannte ODC (Oxygen Depolarised Cathode). Hier wird der Sauerstoff mit den Protonen zu Wasser umgesetzt, was zu einer deutlichen Energieeinsparung gegenüber dem Verfahren mit Diaphragma führt. Für all diese Verfahren zum Auf- bereiten von Salzsäure zu Chlor ist eine hohe Reinheit des Chlorwasserstoffs gefordert. Insbesondere sind hier die organischen Anteile aus der Phosgenierung unerwünscht und hochgradig schädigend für die Performance und Langlebigkeit einer solchen Anlage und insbesondere einer Anlage mit einer ionenleitenden Membran. Diese muss dann mit hohem Aufwand und Kosten ersetzt werden. Further falls hydrochloric acid as a by-product in the preparation of DI (ethylene diphenyl diisocyanate) and TDI (toluene-2,4-diisocyanate), precursors of polyurethanes, in large quantities. TDI is produced by phosgenation of TDA (2,4-diaminotoluene). This gaseous hydrochloric acid is released. In the production of phosgene, chlorine is reacted with carbon monoxide over a catalyst. In the chemical industry, pressure is increasing to convert the hydrochloric acid produced during the production of TDI and MDI back into chlorine. There are three methods available on the market for this purpose. On the one hand the Decon process and on the other two electrochemical processes. In the older method, aqueous hydrochloric acid is supplied to the anode and cathode chambers, which are separated from each other by a diaphragm. At the anode, the chlorine is produced which can be used for the production of phosgene in the recycling cycle. Hydrogen is generated at the cathode. A second electrochemical process is the hydrochloric acid electrolysis using HCI-ODC technology. Here, the anode chamber is fed aqueous hydrochloric acid and the cathode chamber oxygen, both chambers are separated by an ion-conducting membrane. The acid is converted to chlorine and the free protons migrate through the membrane to the cathode, the so-called ODC (Oxygen Depolarised Cathode). Here, the oxygen is reacted with the protons to water, resulting in a significant energy savings compared to the method with diaphragm. For all these processes for preparing hydrochloric acid to chlorine, a high purity of the hydrogen chloride is required. In particular, here are the organic components of the phosgenation undesirable and highly damaging to the performance and longevity of such a system and in particular a system with an ion-conducting membrane. This must then be replaced with great effort and cost.
[0006] Salzsäure enthält indes je nach Herkunft des Ausgangsstoffs und Qualität mitunter so hohe Anteile an organischen Verbindungen, dass sie sich ohne vorherige Reinigung für die weitere Verarbeitung, speziell für den Einsatz in der elektrochemischen Chlorherstellung Hydrochloric acid, however, depending on the origin of the starting material and quality sometimes contains such high levels of organic compounds that they are without prior purification for further processing, especially for use in the electrochemical chlorine production
BESTÄTIGUNGSKOPIE nicht eignet. Es fehlt jedoch bislang an einem geeigneten Verfahren, mit dessen Hilfe man schnell und zuverlässig auch organischen Kohlenstoff in Mengen bis zu 0,1 mg/l TOC (total organic carbon) bestimmen kann, um auf diese Weise zu entscheiden, ob eine Charge für die weitere Verwendung geeignet ist oder zunächst gereinigt werden muss. CONFIRMATION COPY not suitable. However, there is still a lack of a suitable method by which one can quickly and reliably determine organic carbon in amounts up to 0.1 mg / l TOC (total organic carbon), in order to decide whether a batch for the further use is suitable or must first be cleaned.
[0007] Gleiche Probleme treten auch im Zusammenhang mit anderen Mineralsäuren auf, die beispielsweise zur Gewinnung von Fluor oder Brom eingesetzt werden. The same problems occur in connection with other mineral acids, which are used for example for the production of fluorine or bromine.
[0008] In diesem Zusammenhang sei auf das chinesische Gebrauchsmuster CN 201555755 U hingewiesen, aus dem die Bestimmung des TOC-Gehaltes in Meerwasser durch Umwandlung des organischen Kohlenstoffs mit Hilfe von UV-Strahlung und Persulfat in Kohlendioxid und nachfolgende Bestimmung des C02-Gehaltes beschrieben wird. Die chemische Oxidation ist jedoch aufwendig und häufig nicht vollständig, insbesondere aber nicht geeignet, um auch noch kleinste Mengen an Verunreinigungen zu erfassen. In this context, reference is made to the Chinese utility model CN 201555755 U, from which the determination of the TOC content in seawater by conversion of the organic carbon using UV radiation and persulfate in carbon dioxide and subsequent determination of C0 2 content described becomes. However, the chemical oxidation is complex and often not complete, but especially not suitable to detect even the smallest amounts of impurities.
[0009] Die Aufgabe der vorliegenden Erfindung hat somit darin bestanden, eine Vorrichtung und ein Verfahren zur Verfügung zu stellen, dass den geschilderten Problemen abhilft. Die- ses Verfahren sollte es insbesondere erlauben atline, online und vorzugsweise in kontinuierlicher Weise unterschiedliche wässrige Mineralsäuren sowohl mit hohen als auch niedrigen nicht-wässrigen Anteilen, daraufhin zu untersuchen, ob und in welchen Mengen sie organische Kohlenstoffverbindungen enthalten. Dabei sollte das Verfahren so ausgestaltet sein, dass auch noch TOC-Mengen im Bereich von 0,1 mg/l detektiert werden können. The object of the present invention has thus been to provide an apparatus and a method available that remedies the problems outlined. In particular, this method should allow atline, on-line, and preferably continuously different, aqueous mineral acids with both high and low nonaqueous fractions to be screened to see if and how much organic carbon compounds they contain. The process should be designed in such a way that even TOC amounts in the range of 0.1 mg / l can be detected.
[0010] BESCHREIBUNG DER ERFINDUNG DESCRIPTION OF THE INVENTION
[0011] Gegenstand der Erfindung ist ein Verfahren, vorzugsweise in kontinuierlicher Fahrweise, zur Bestimmung des Gehaltes an organischen Kohlenstoffverbindungen in Mineralsäuren, bei dem man The invention relates to a method, preferably in continuous operation, for determining the content of organic carbon compounds in mineral acids, in which
(a) die wässrige oder gasförmige Mineralsäuren in eine Brennkammer eindosiert und bei Temperaturen im Bereich von 500 bis 1500 °C mit einem Strom gereinigter Brennluft vermischt, (A) the aqueous or gaseous mineral acids are metered into a combustion chamber and mixed at temperatures in the range of 500 to 1500 ° C with a stream of purified combustion air,
die so erhaltenen Verbrennungsgase aus der Brennkammer ausgeschleust und so weit abgekühlt, dass sich alle Beistoffe mit einem Taupunkt unter 20 °C als Flüssigkeiten abscheiden, the combustion gases thus obtained are discharged from the combustion chamber and cooled to such an extent that all co-formulants with a dew point below 20 ° C. separate out as liquids,
die flüssige von der gasförmigen Phase abtrennt, und separating the liquid from the gaseous phase, and
die Gasphase einem Prozessanalysator zuleitet, in dem der Gehalt an Kohlenoxiden ermittelt wird. the gas phase fed to a process analyzer, in which the content of carbon oxides is determined.
[0012] Das erfindungsgemäße Verfahren bietet gegenüber dem Stand der Technik eine Rei- he von Vorteilen: The method according to the invention offers a number of advantages over the prior art:
[0013] Im Gegensatz zu einer diskontinuierlichen Messung mit sequenzieller Probenaufgabe und Analyse, erlauben die kontinuierliche Eindosierung der Mineralsäuren in die Brennkammer und der kontinuierliche Fluss der Probe zum Analysator eine ebenso kontinuierliche Bestimmung des TOC-Gehaltes als Funktion der Zeit. In contrast to a discontinuous measurement with sequential sample application and analysis, the continuous metering of the mineral acids into the combustion chamber and the continuous flow of the sample to the analyzer allow an equally continuous determination of the TOC content as a function of time.
[0014] Durch die direkte thermische Umsetzung der Kohlenwasserstoffe zu Kohlendioxid ist der Einfluss der Natur der Mineralsäure auf das Analysenergebnis vernachlässigbar gering. Dabei hat es sich überraschend herausgestellt, dass die Anwesenheit von Katalysatoren zur Unterstützung der Oxidation nicht erforderlich ist. Due to the direct thermal reaction of the hydrocarbons to carbon dioxide, the influence of the nature of the mineral acid on the analysis result is negligible. It has surprisingly been found that the presence of catalysts to support the oxidation is not required.
[0015] Da die Umsetzung thermisch durchgeführt wird, werden keine zusätzlichen Chemikalien, insbesondere keine Persulfate benötigt. Die Umsetzung mit dem in den Brenngasen enthaltenen Sauerstoff wird durch die stark saure Matrix auch nicht beeinflusst. Die Probe wird vollständig verdampft und reagiert in der Gasphase. Ein späteres Ausstrippen des Kohlendioxids und die damit verbundenen Messfehler durch ein nicht vollständiges Strippen werden zuverlässig vermieden. Durch die direkte Verdampfung der Probe bleibt diese sauer. Dadurch ist der Anteil des Kohlendioxids in der flüssigen Phase des Probenkühlers klein, da die Löslichkeit von Kohlendioxid in stark sauren Medien sehr gering ist. Auch hierdurch werden Messfehler vermieden. Since the reaction is carried out thermally, no additional chemicals, in particular no persulfates are needed. The reaction with the oxygen contained in the combustion gases is also not affected by the strongly acidic matrix. The sample is completely evaporated and reacts in the gas phase. A later stripping of the carbon dioxide and the associated measurement errors by incomplete stripping are reliably avoided. The direct evaporation of the sample remains acidic. As a result, the proportion of carbon dioxide in the liquid phase of the sample cooler is small, since the solubility of carbon dioxide in strongly acidic media is very low. This also avoids measurement errors.
[0016] Mineralsäuren Mineral acids
[0017] Hinsichtlich der Mineralsäuren, deren TOC-Gehalt es zu bestimmen gilt, gibt es kaum Einschränkungen. Es empfiehlt es sich indes, solche einzusetzen, die keine signifikanten IR- Absorptions-Banden im Bereich von Kohlendioxid aufweisen, da andernfalls die Messwerte verfälscht werden könnten. With respect to the mineral acids whose TOC content it is to determine, there are hardly any restrictions. However, it is advisable to use those that have no significant IR absorption bands in the range of carbon dioxide, as otherwise the measured values could be falsified.
[0018] Typische Beispiele für geeignete Mineralsäuren sind Flusssäure (HF), Bromsäure (HBr), Jodsäure (Hl), Hypochlorige Säure (HCIO), Chlorsäure (HCIO3) und Perchlorsäure (HCIO4). Die größte Bedeutung hat indes natürlich Salzsäure (HCl) als Einsatzstoff. Typical examples of suitable mineral acids are hydrofluoric acid (HF), bromic acid (HBr), iodic acid (Hl), hypochlorous acid (HCIO), chloric acid (HCIO3) and perchloric acid (HCIO4). Of course, the greatest importance is hydrochloric acid (HCl) as a feedstock.
[0019] Wässrige Mineralsäuren können bis zur maximalen Konzentration eingesetzt werden. Vorzugsweise weisen die Mineralsäuren einen wässrigen Anteil von mindestens etwa 63 Gew.-%, insbesondere etwa 65 bis etwa 80 und besonders bevorzugt von etwa 70 bis etwa 90 Gew.-% auf. Im Fall der Salzsäure können beispielsweise Lösungen mit einer Konzentrati- on von bis zu 37 Gew.-% (HCl) eingesetzt werden. Ebenfalls geeignet sind gasförmige Mineralsäuren, die frei von Verunreinigungen sind, welche die Messung von Kohlendioxid stören Aqueous mineral acids can be used up to the maximum concentration. Preferably, the mineral acids have an aqueous content of at least about 63% by weight, more preferably from about 65 to about 80, and most preferably from about 70 to about 90% by weight. In the case of hydrochloric acid, for example, solutions having a concentration of up to 37% by weight (HCl) can be used. Also suitable are gaseous mineral acids that are free of impurities that interfere with the measurement of carbon dioxide
[0020] Schritt I: Verbrennung Step I: combustion
[0021] Im ersten Schritt des erfindungsgemäßen Verfahrens wird eine Probe, vorzugsweise ein kontinuierlicher Strom der wässrigen oder gasförmigen Mineralsäuren in eine Brennkammer gefördert. Der Durchsatz an Mineralsäure liegt vorzugsweise bei etwa 10 bis etwa 100 ml/h, insbesondere etwa 20 bis etwa 80 ml/h und besonders bevorzugt bei etwa 30 bis etwa 50 ml/h. Das Eindosieren erfolgt dabei vorzugsweise im Sinne einer Vertropfung, d.h. einzelne Tropfen der wässrigen Mineralsäuren treten in die Brennkammer ein und Verdamp- fen entweder sofort oder spätestens beim Aufschlagen auf eine Prallplatte. In the first step of the method according to the invention, a sample, preferably a continuous stream of aqueous or gaseous mineral acids is conveyed into a combustion chamber. The throughput of mineral acid is preferably from about 10 to about 100 ml / h, in particular from about 20 to about 80 ml / h and particularly preferably from about 30 to about 50 ml / h. The dosing is preferably carried out in the sense of a dripping, i. individual drops of aqueous mineral acids enter the combustion chamber and evaporate either immediately or at the latest when they hit a baffle plate.
[0022] Die Mineralsäuren, deren TOC-Gehalt es zu bestimmen gilt, werden in der Brennkammer mit Verbrennungsgasen vermischt, die über einen zweiten Einlass in die Kammer eingedüst werden. Die Verbrennungsgase sind zuvor gereinigt worden, so dass sie selbst keine Kohlenstoffoxide enthalten; es handelt sich dabei um Sauerstoff, insbesondere aber Luft, die vorzugsweise schon vorgeheizt worden ist. Die Brenngase werden in großem Über- schuss eingesetzt, wobei die Volumenströme vorzugsweise etwa 20 bis etwa 30 Nl/h beträgt. [0023] Die Brennkammer ist im weitesten Sinne ein Ofen, bei dem die Wärme über die Wandungen abgestrahlt wird; eine Flamme ist also nicht vorhanden. In der Regel besteht die Kammer aus Keramik oder einem anderen Werkstoff, der geeignet ist die hohen Temperaturen von 500 bis 1500 °C, typisch 650 bis 750 °C auszuhalten und auch gegenüber den sauren Medien hinreichend korrosionsbeständig ist. The mineral acids, whose TOC content is to be determined, are mixed in the combustion chamber with combustion gases, which are injected via a second inlet into the chamber. The combustion gases have been previously purified so that they themselves do not contain carbon oxides; it is oxygen, but especially air, which has preferably already been preheated. The fuel gases are used in large excess, wherein the volume flows preferably about 20 to about 30 Nl / h. The combustion chamber is in the broadest sense an oven in which the heat is radiated through the walls; a flame is not there. In general, the chamber is made of ceramic or other material that is suitable to withstand the high temperatures of 500 to 1500 ° C, typically 650 to 750 ° C and is also sufficiently resistant to corrosion of the acidic media.
Schritt II: Abkühlung Step II: Cool down
[0024] Mit dem Eindosieren in die Brennkammer werden Mineralsäuren, die wässrig vorliegen verdampft und die organischen Anteile in Kohlendioxid überführt. Gasförmige Mineral- säuren können direkt eingeleitet werden. Die Reaktionsgase werden nach Verlasen der Brennkammer in einen Separator geleitet, in dem sie so stark abgekühlt werden, dass alle Bestandteile, die bei Umgebungstemperatur flüssig vorliegen, abgeschieden werden. Dies trifft insbesondere für den Wasseranteil zu. Üblicherweise erfolgt die Abkühlung auf etwa 5 bis etwa 15 °C. With the dosing into the combustion chamber, mineral acids which are present in aqueous form are vaporized and the organic components are converted into carbon dioxide. Gaseous mineral acids can be introduced directly. The reaction gases are passed after leaving the combustion chamber in a separator in which they are cooled so strongly that all components that are liquid at ambient temperature, are deposited. This is especially true for the water content. Usually, the cooling is carried out at about 5 to about 15 ° C.
[0025] Schritt III: Detektion Step III: Detection
[0026] Nachdem die flüssigen Bestandteile über ihren Taupunkt hinweg abgekühlt und durch Phasentrennung entfernt worden sind, werden die so getrockneten Reaktionsgase einem Detektor zugeführt, der in der Lage ist, Kohlenoxide, insbesondere Kohlendioxid zu analysieren. Die Analyse kann dabei spektroskopisch oder photometrisch erfolgen. Besonders bevorzugt sind IR-Verfahren, wie insbesondere die NDIR-Detektion (Non Dispersive Inf- rared). Alternativ kommen auch laserspektroskopische Verfahren oder eine Gaschromatographie in Betracht. After the liquid components have been cooled beyond their dew point and removed by phase separation, the thus dried reaction gases are fed to a detector which is capable of analyzing carbon oxides, in particular carbon dioxide. The analysis can be carried out spectroscopically or photometrically. Particularly preferred are IR methods, in particular the NDIR detection (Non Dispersive Infared). Alternatively, laser spectroscopic methods or gas chromatography are also possible.
[0027] Die Kalibrierung des Systems kann erfolgen, indem man zuvor Gase mit definiertem Kohlenstoffgehalt (Kalibriergase) vermisst oder wässrige Mineralsäuren mit definiertem TOC einsetzt. The calibration of the system can be done by previously measuring gases with a defined carbon content (calibration gases) or using aqueous mineral acids with a defined TOC.
[0028] Ein weiterer Gegenstand der Erfindung ist auf eine Vorrichtung zur Bestimmung des Gehaltes an organischen Kohlenstoffverbindungen in wässrigen Mineralsäuren gerichtet, umfassend Another object of the invention is directed to an apparatus for determining the content of organic carbon compounds in aqueous mineral acids, comprising
(i) eine Brennkammer mit Zuführungen für die Mineralsäuren und die Brenngase sowie eine Abführung der Verbrennungsgase, (I) a combustion chamber with feeds for the mineral acids and the combustion gases and a discharge of the combustion gases,
(ii) einen mit der Brennkammer verbundenen Separator, in dem die Verbrennungsgase so weit abgekühlt werden, dass sich eine flüssige Phase niederschlägt, sowie (ii) a separator connected to the combustion chamber, in which the combustion gases are cooled so far that precipitates a liquid phase, and
(iii) einen mit dem Separator verbundenen Detektor mit der Eignung zur Bestimmung des Gehaltes an Kohlenoxiden in der verbliebenen Gasphase. (iii) a detector connected to the separator and capable of determining the content of carbon oxides in the remaining gas phase.
[0029] Eine entsprechende Vorrichtung ist in Fig. 1 wiedergegeben: Die Brenngase werden über einen Kohlendioxid- und einen Säureabsorber gereinigt und in die Brennkammer des Reaktors geleitet. In diesen wird die wässrige Mineralsäure vertropft. Die Verbrennungsgase werden dann über einen Kühler mit angeschlossenem Flüssigkeitsabscheider geleitet und die getrockneten Gase dann dem Analysator zugeführt. A corresponding device is shown in Fig. 1: The fuel gases are purified by a carbon dioxide and an acid absorber and passed into the combustion chamber of the reactor. In these, the aqueous mineral acid is dripped. The combustion gases are then passed through a condenser with attached liquid separator and the dried gases are then fed to the analyzer.
Claims
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| DE102013021751.2 | 2013-12-20 | ||
| DE102013021751.2A DE102013021751B4 (en) | 2013-12-20 | 2013-12-20 | Method for determining the content of organic carbon compounds in mineral acids |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3904364A (en) * | 1972-02-18 | 1975-09-09 | Nat Res Dev | Methods of and apparatus for determining trace impurities |
| DE4418619A1 (en) * | 1994-05-27 | 1995-11-30 | Fraunhofer Ges Forschung | Appts. for determn. of carbon content of conc. mineral acids |
| EP1225447A2 (en) * | 2001-01-05 | 2002-07-24 | Dimatec Analysentechnik GmbH | Method for TC and TNb measurement in water samples and catalyser |
| CN201555755U (en) | 2009-10-18 | 2010-08-18 | 中国海洋大学 | A device for automatic monitoring of total organic carbon in seawater |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3296435A (en) * | 1964-07-06 | 1967-01-03 | Dow Chemical Co | Method and apparatus for determining the total carbon content of aqueous systems |
| US3530292A (en) * | 1967-04-26 | 1970-09-22 | Union Carbide Corp | Apparatus and method for determination and measurement of carbon in aqueous solutions |
| DE2811135C2 (en) * | 1978-03-15 | 1986-04-24 | Hoechst Ag, 6230 Frankfurt | Method for the quantitative determination of carbon organic compounds in water |
| DE19836215A1 (en) * | 1997-08-12 | 1999-02-18 | Elementar Analysensysteme Gmbh | Reactor for an elemental analysis system |
-
2013
- 2013-12-20 DE DE102013021751.2A patent/DE102013021751B4/en not_active Expired - Fee Related
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2014
- 2014-12-17 WO PCT/EP2014/003413 patent/WO2015090593A1/en not_active Ceased
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3904364A (en) * | 1972-02-18 | 1975-09-09 | Nat Res Dev | Methods of and apparatus for determining trace impurities |
| DE4418619A1 (en) * | 1994-05-27 | 1995-11-30 | Fraunhofer Ges Forschung | Appts. for determn. of carbon content of conc. mineral acids |
| EP1225447A2 (en) * | 2001-01-05 | 2002-07-24 | Dimatec Analysentechnik GmbH | Method for TC and TNb measurement in water samples and catalyser |
| CN201555755U (en) | 2009-10-18 | 2010-08-18 | 中国海洋大学 | A device for automatic monitoring of total organic carbon in seawater |
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| DE102013021751A1 (en) | 2015-06-25 |
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