Other language confidence: 0.6208743063117599
Die Ergebnisse eines vorangegangenen DFG-Projektes lieferten Hinweise darauf, dass die verstärkte Abgabe von Citrat und Protonen unter P-Mangelbedingungen auf einer erhöhten Akkumulation von Citronensäure im Wurzelgewebe beruht. Diese verstärkte Citratakkumulation ist einerseits die Folge einer erhöhten Biosyntheserate, beruht andererseits aber wahrscheinlich auch auf einem durch P-Limitierung der Atmungskette verminderten Citratumsatz im Citratcyklus. Zur Prüfung dieser Hypothese sollen P-Mangel induzierte Veränderungen der am Citratumsatz beteiligten Stoffwechselwege untersucht werden, um so Hinweise auf die an der Regulation beteiligten Schlüsselreaktionen zu erhalten. Im einzelnen sind Messungen der Wurzelatmung, des Pools an Adeninnukleotiden, des Redoxstatus (NADH/NAD-Verhältnis), 14C markierter Intermediärprodukte des Citratstoffwechsels und der an den Umsetzungen beteiligten Enzymaktivitäten, sowie Untersuchungen zur Citratakkumulation nach gezielter Applikation von Respirationshemmstoffen (KCN, SHAM) geplant. Die Wirksamkeit verschiedener Anionenkanalinhibitoren lieferte erste Hinweise, dass die Citratabgabe durch einen Anionenkanal im Plasmalemma erfolgt. Nach Isolierung von Protoplasten aus dem Proteoidwurzelgewebe soll über Patch-Clamp Messungen versucht werden, die Beteiligung eines Anionenkanals direkt nachzuweisen.
Zielsetzung und Anlass des Vorhabens: Motivation Bis 2045 will Deutschland erreichen, dass die Bilanzen der Industrie und damit auch die der Glasindustrie klimaneutral auszuweisen sind. Die Glasindustrie in Deutschland stößt z.Zt. etwa 5,4 Mio. t CO2 bei einer Jahresproduktion von 7,4 Mio. t Glas aus. Der Anteil der eingesetzten Menge an natürlichen und synthetischen Rohstoffen im Massenglasbereich Behälter- und Fensterglas mit einer Jahresproduktion von 6 Mio. t Glas beträgt hier 3,3 Mio. t Rohstoffe ohne Scherben. Von diesen 3,3 Mio. t gelangen ca. 20% als CO2 (0,66 Mio. t) in die Atmosphäre, da ein Teil der Rohstoffe karbonatische Natur besitzen. Im Rahmen dieses Projektes wird versucht, den Ausstoß von klimaschädlichem CO2 aus diesen Rohstoffen (Karbonate) in der Glasindustrie zu verringern. Das soll durch den Einsatz von oxydischen oder hydroxydischen Rohstoffen als Ersatzrohstoff für karbonatische Rohstoffe sowie durch den Einsatz von Fein-Scherben erreicht werden. Im Rahmen dieses Projektes soll die technologische Einsetzbarkeit von alternativen Rohstoffen mittels Engineerings und Laboruntersuchungen bewertet und die Hindernisse für ihren Einsatz in der Glasindustrie beseitigt werden. Ziel des Projektes Die Hauptziele des Projektes in Bezug auf die Behälter- und Flachglasindustrie sind: a) Vermeidung der Anbackung beim Einsatz von oxydischen oder hydroxydischen Rohstoffen als Ersatzrohstoff für karbonatische Rohstoffe. b) Bewertung des Einflusses von Branntkalk / Löschkalk und Natriumhydroxid unter Berücksichtigung unterschiedlicher Scherbengehalte auf das Schmelzverhalten zur Klärung der Intensivierungsmöglichkeiten der Glasherstellung durch diese alternativen Rohstoffe und der damit verbundenen Möglichkeiten zur Reduzierung der Primärschaumproblematik beim Einsatz von Feinscherben.
Die H.C. Starck Tungsten GmbH produziert aus Recyclingmaterialien und Erzen hochleistungsfähige Wolfram-Pulver und Wolfram-Verbindungen für den Maschinen- und Werkzeugbau, die Automobil- und Energieindustrie, die Luftfahrt sowie die Chemische Industrie. Das Unternehmen beschäftigt weltweit 550 Mitarbeiter. Ein wichtiges Produkt der Wolframchemie ist Ammoniummetawolframat (AMW), welches u.a. als Vorstoff für Industriekatalysatoren verwendet wird. Bisher wurde dieser Stoff über ein energieintensives mehrstufiges Aufbereitungsverfahren produziert. Dabei wurden mehrere Verdampfer zum Wasserentzug bzw. zur Aufkonzentrierung der AMW-Lösung verwendet. Darüber hinaus musste die AMW-Lösung mehrmals im Kreis gefahren werden, um die gewünschte Konzentration zu erreichen. Die Umkehrosmosetechnologie wurde nach dem bisherigen Stand der Technik vorrangig im Bereich der Trinkwasseraufbereitung, der Behandlung von nitrathaltigen Abwässern in der chemischen Industrie sowie zur Meerwasserentsalzung eingesetzt. Ziel des Projektes war die energieeffiziente Herstellung von Ammoniummetawolframat (AMW) aus wolframhaltigen Schrotten durch den erstmaligen Einsatz der Hochdruckumkehrosmose zur Aufkonzentrierung von AMW. Dabei sollte der Verdampfungsprozess durch eine energieeffiziente Umkehrosmoseanlage mit Arbeitsdrücken von über 100 bar substituiert werden. Die Hauptinnovation des Projektes besteht darin, dass die Hochdruckumkehrosmose erstmalig nicht nur auf einfache anorganische Salze in wässriger Lösung angewendet wird, sondern auf Isopolyionen bildende Metallate, bei denen zum Teil sehr komplizierte Gleichgewichte zwischen verschiedenen Spezies bestehen, die durch möglicherweise auftretende selektive Ionenpermeabilitäten der Membran nicht gestört werden dürfen. Kern der Anlage sind zwei parallel geschaltete Druckrohre, von denen jedes mit maximal drei Membranwickelmodulen bestückt werden kann. Diese werden über eine Kreislaufpumpe von ihrer Stirnseite her mit mehreren Kubikmetern pro Stunde auf der Konzentratseite durchströmt. Diesem Kreislauf wird über eine vorgeschaltete Vordruckpumpe und eine Hochdruckpumpe Feedlösung geringerer Konzentration zugeführt. Die Membranen haben sich auch im Langzeitbetrieb als stabil erwiesen, was die wirtschaftliche Nutzung dieser Technologie erst ermöglicht. Im Vergleich zum herkömmlichen Verdampfungsverfahren konnte durch die Hochdruckumkehrosmose eine Energieeinsparung von über 97 Prozent erzielt werden. Bei einer jährlichen Produktionsmenge von 1.000 Tonnen AMW entspricht das einer Einsparung von 5600 Megawattstunden Energie und damit ca. 1.021 Tonnen CO 2 -Äquivalente bzw. ca. 1.023 Kilogramm CO 2 -Äquivalente pro Tonne AMW. Da die H.C. Starck Tungsten GmbH ausschließlich Strom aus erneuerbaren Quellen bezieht, beträgt die CO 2 -Einsparung 100 Prozent. Zusätzlich zur Energieeinsparung wurde auch der Verbrauch an Natronlauge (50-prozentige NaOH) um ca. 39 Tonnen pro Jahr gesenkt. Die Emissionen an Neutralsalz (Na 2 SO 4 ) über das behandelte Abwasser konnten so um etwa 35 Tonnen pro Jahr reduziert werden. Das Vorhaben hat einen sehr guten Modellcharakter und ist prinzipiell auch auf andere Anwendungen zur Aufkonzentrierung von Metallaten oder auf andere komplizierte chemische Systeme übertragbar. Branche: Chemische und pharmazeutische Erzeugnisse, Gummi- und Kunststoffwaren Umweltbereich: Klimaschutz Fördernehmer: H.C. Starck Tungsten GmbH Bundesland: Niedersachsen Laufzeit: 2018 - 2020 Status: Abgeschlossen
In den USA wurde eine neue Methode entwickelt, welche Nägel und Messer nicht nur schärfer, robuster und widerstandsfähiger macht, sondern sich auch als umweltfreundlicher und kostengünstiger in der Herstellung erweist. Die Forscher*innen konnten mit einem einfachem Verfahren Holz bis zu 23-mal härter machen als zuvor, indem sie zwei Prozessschritte verfolgen: zu anfangs wird mit einer chemischen Behandlung ein Teil des Lignins und Hemicellulose entfernt, was dazu führt, dass das Holz weich und leicht schwammig wird. Die Holzblöcke werden hierfür in eine wässrige Lösung mit Natriumhydroxid (NaOH; 5% Gewichtsanteil)) und Natriumsulfit (Na2SO3; 2,5%) gelegt, bis sich die Poren vollgesogen haben. Im darauffolgenden Schritt wird das Wasser im Holz entfernt durch das Einwirken von Druck und Hitze. Hierfür wird die Lösung bei 100 Grad für mehrere Stunden zum Kochen gebracht. Anschließend wird das Holz abgespült und getrocknet um Anschluss mit Mineralölen versiegelt damit es hydrophob wird. Das Verfahren hat am Beispiel mit Lindenholz bewiesen, dass die Schärfe und Härte eines Messers erreicht werden konnte.
technologyComment of chlor-alkali electrolysis, diaphragm cell (RER, RoW): In the diaphragm process, all reactions take place in only one cell. A diaphragm is used to separate the feed brine (anolyte) and the chlorine formed at the anode from the sodium hydroxide containing solution (catholyte) and the hydrogen formed at the cathode. Without the diaphragm being present during electrolysis, chlorine and hydrogen would form an explosive mixture and sodium hydroxide and chlorine would react to form sodium hypochlorite (NaOCl). Diaphragms used to be made from asbestos but up-todate technology allows for asbestos-free polymer-based diaphragms. Purified brine is fed to the anode compartment and percolates through the diaphragm into the cathode compartment. The percolation rate is controlled by a difference in liquid level between both compartments. At the anodes (metal oxide coated titanium), chlorine gas is formed which is collected and directed to further processing. Cathodes, where water decomposition takes place, are made of activated carbon steel. Catholyte leaving the cell, also called cell liquor, is a mixture of 10-12 wt.-% sodium hydroxide and 15-17 wt.-% sodium chloride in water. This solution is usually evaporated to 50 wt.-% NaOH. In this process, simultaneously most of the salt is removed by precipitation to a final residual of 1 wt.-%. The resulting salt is typically recirculated to brine preparation. The advantage of diaphragm cells is that the quality requirements for the brine and the electrical energy consumption are low. Disadvantageous are the high amount of thermal energy necessary for sodium hydroxide concentration and the comparably low quality of the produced sodium hydroxide and chlorine. References: Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). technologyComment of chlor-alkali electrolysis, membrane cell (CA-QC, RER, RoW): In the membrane cell process, the anode and cathode compartments are separated by a perfluoropolymer cation-exchange membrane that selectively transmits sodium ions but suppresses the migration of hydroxyl ions (OH-) from the catholyte into the anolyte. Saturated brine flows through the anode compartment, where chlorine gas is produced at the anode. The electric field in the electrolysis cell causes hydrated sodium ions to migrate through the membrane into the cathode compartment. The cathode compartment is fed with diluted sodium hydroxide solution. Water is electrolysed at the cathode releasing gaseous hydrogen and hydroxyl ions, which combine with the sodium ions and thus increase the concentration of sodium hydroxide in the catholyte. Typically, the outlet concentration of sodium hydroxide is around 32 wt.-%. A part of the product stream is diluted with demineralised water to about 30 wt.-% and used as catholyte inlet. In some units, a more diluted 23 wt.-% NaOH solution is produced. In these cases, the inlet concentration is adjusted to 20-21 wt.-%. Usually the NaOH solution is evaporated to the marketable concentration of 50 wt.-% using steam. Depleted brine leaving the anode compartment is saturated with chlorine and is therefore sent to a dechlorination unit to recover the dissolved chlorine before it is resaturated with salt for recirculation. The advantages of the membrane cell technique are the very high purity of the sodium hydroxide solution produced and the comparably low energy demand. Disadvantages comprise the high requirements on brine purity, the need for sodium hydroxide evaporation to increase concentration, and the comparably high oxygen content in the produced chlorine. In general, multiple cell elements are combined into a single unit, called electrolyser, of whom the design can be either monopolar or bipolar. In a monopolar electrolyser, the anodes and cathodes of the cells are connected electrically in parallel, whereas in the bipolar design, they are connected in series. Therefore, monopolar electrolysers require high current and low voltage, whereas bipolar electrolysers require low current and high voltage. Since bipolar systems allow higher current densities inside the cells, investment and operating costs are usually lower than for monopolar systems. References: Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). technologyComment of chlor-alkali electrolysis, mercury cell (RER, RoW): The mercury cell process comprises an electrolysis cell and a decomposer. Purified and saturated brine (25-28 wt.-% NaCl in water) is fed to the electrolysis cell on top of a film of mercury (Hg) flowing down the inclined base of the cell. The base of the cell is connected to the negative pole of a direct current supply forming the cathode of the cell. Anodes consisting of titanium coated with oxides of ruthenium and titanium are placed in the brine without touching the mercury film. At the anodes, chlorine gas is formed which is collected and directed to further processing. Due to a high overpotential of hydrogen at the mercury electrode, no gaseous hydrogen is formed; instead, sodium is produced and dissolved in the mercury as an amalgam (mercury alloy). The liquid amalgam is removed from the electrolytic cell and fed to a decomposer, where it reacts with demineralised water in the presence of a graphite-based catalyst to form sodium hydroxide solution and hydrogen. The sodium-free mercury is recirculated back into the cell. Cooling of hydrogen is essential to remove any water and mercury. The sodium hydroxide solution is very pure, almost free from chloride contamination and has usually a concentration of 50 %. Further treatment comprises cooling and removal of catalyst and mercury traces by centrifuges or filters. Advantages of the mercury cell process are the high quality of chlorine and the high concentration and purity of sodium hydroxide solution produced. The consumption of electric energy for electrolysis is, however, higher than for the other techniques and a high purity of the feed brine is required. Inherently, the use of mercury gives rise to environmental releases of mercury. References: Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process).
technologyComment of cryolite production (RER, RoW): Production by the hydrofluoric acid technique. In a first step, alumina trihydrate is leached by hydrofluoric acid - in the second step cryolite is precipitated by adding sodium hydroxide. The overall process yield is of 98%. Inventory bases on stoechiometric calculations. The emissions to air (0.2 wt.% of HF input) and water were estimated using mass balance. technologyComment of cryolite production, from fluosilicic acid (GLO): The main production of cryolite involves hydrofluoric acid or fluosilicic acid. In both cases, the reactants can be combined with a variety of materials, such as Al2O3 · 3 H2O, Al2O3 · x NaOH, NaOH, NaCl, and Na2SO4. During the present reaction, fluosilicic acid is neutralised with sodium hydroxide. Then it reacts with Al2O3 to produce cryolite and silica. The reaction process is shown below: Al2O3 + 2H2SiF6 + 6 NaOH --> 2 Na3AlF6 + 2 SiO2 + 5 H2O It is difficult to predict how much of the cryolite is produced with the present reaction, since many production routes exist. The present inventory serves as an illustration of the cryolite production from fluosilicic acid. The alternative production route with HF is still considered to be the main production route (source: Ullmann encyclopedia, Cryolite, 2005).
technologyComment of cryolite production, from fluosilicic acid (GLO): The main production of cryolite involves hydrofluoric acid or fluosilicic acid. In both cases, the reactants can be combined with a variety of materials, such as Al2O3 · 3 H2O, Al2O3 · x NaOH, NaOH, NaCl, and Na2SO4. During the present reaction, fluosilicic acid is neutralised with sodium hydroxide. Then it reacts with Al2O3 to produce cryolite and silica. The reaction process is shown below: Al2O3 + 2H2SiF6 + 6 NaOH --> 2 Na3AlF6 + 2 SiO2 + 5 H2O It is difficult to predict how much of the cryolite is produced with the present reaction, since many production routes exist. The present inventory serves as an illustration of the cryolite production from fluosilicic acid. The alternative production route with HF is still considered to be the main production route (source: Ullmann encyclopedia, Cryolite, 2005). technologyComment of silica sand production (DE, RoW): Generally there are no differences in the quarrying process of silica sand compared to the “normal” sand process. An important difference is that silica sand is dried. It is assumed that the content of moisture before drying is about 5% and afterwards around 1%. Another difference is based on the high content of SiO2, which makes the raw material rarer. Losses in the conveyor belt transportation are taken into account.
technologyComment of chlor-alkali electrolysis, diaphragm cell (RER): In the diaphragm process, all reactions take place in only one cell. A diaphragm is used to separate the feed brine (anolyte) and the chlorine formed at the anode from the sodium hydroxide containing solution (catholyte) and the hydrogen formed at the cathode. Without the diaphragm being present during electrolysis, chlorine and hydrogen would form an explosive mixture and sodium hydroxide and chlorine would react to form sodium hypochlorite (NaOCl). Diaphragms used to be made from asbestos but up-todate technology allows for asbestos-free polymer-based diaphragms. Purified brine is fed to the anode compartment and percolates through the diaphragm into the cathode compartment. The percolation rate is controlled by a difference in liquid level between both compartments. At the anodes (metal oxide coated titanium), chlorine gas is formed which is collected and directed to further processing. Cathodes, where water decomposition takes place, are made of activated carbon steel. Catholyte leaving the cell, also called cell liquor, is a mixture of 10-12 wt.-% sodium hydroxide and 15-17 wt.-% sodium chloride in water. This solution is usually evaporated to 50 wt.-% NaOH. In this process, simultaneously most of the salt is removed by precipitation to a final residual of 1 wt.-%. The resulting salt is typically recirculated to brine preparation. The advantage of diaphragm cells is that the quality requirements for the brine and the electrical energy consumption are low. Disadvantageous are the high amount of thermal energy necessary for sodium hydroxide concentration and the comparably low quality of the produced sodium hydroxide and chlorine. References: Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). technologyComment of chlor-alkali electrolysis, membrane cell (RER): In the membrane cell process, the anode and cathode compartments are separated by a perfluoropolymer cation-exchange membrane that selectively transmits sodium ions but suppresses the migration of hydroxyl ions (OH-) from the catholyte into the anolyte. Saturated brine flows through the anode compartment, where chlorine gas is produced at the anode. The electric field in the electrolysis cell causes hydrated sodium ions to migrate through the membrane into the cathode compartment. The cathode compartment is fed with diluted sodium hydroxide solution. Water is electrolysed at the cathode releasing gaseous hydrogen and hydroxyl ions, which combine with the sodium ions and thus increase the concentration of sodium hydroxide in the catholyte. Typically, the outlet concentration of sodium hydroxide is around 32 wt.-%. A part of the product stream is diluted with demineralised water to about 30 wt.-% and used as catholyte inlet. In some units, a more diluted 23 wt.-% NaOH solution is produced. In these cases, the inlet concentration is adjusted to 20-21 wt.-%. Usually the NaOH solution is evaporated to the marketable concentration of 50 wt.-% using steam. Depleted brine leaving the anode compartment is saturated with chlorine and is therefore sent to a dechlorination unit to recover the dissolved chlorine before it is resaturated with salt for recirculation. The advantages of the membrane cell technique are the very high purity of the sodium hydroxide solution produced and the comparably low energy demand. Disadvantages comprise the high requirements on brine purity, the need for sodium hydroxide evaporation to increase concentration, and the comparably high oxygen content in the produced chlorine. In general, multiple cell elements are combined into a single unit, called electrolyser, of whom the design can be either monopolar or bipolar. In a monopolar electrolyser, the anodes and cathodes of the cells are connected electrically in parallel, whereas in the bipolar design, they are connected in series. Therefore, monopolar electrolysers require high current and low voltage, whereas bipolar electrolysers require low current and high voltage. Since bipolar systems allow higher current densities inside the cells, investment and operating costs are usually lower than for monopolar systems. References: Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). technologyComment of chlor-alkali electrolysis, mercury cell (RER): The mercury cell process comprises an electrolysis cell and a decomposer. Purified and saturated brine (25-28 wt.-% NaCl in water) is fed to the electrolysis cell on top of a film of mercury (Hg) flowing down the inclined base of the cell. The base of the cell is connected to the negative pole of a direct current supply forming the cathode of the cell. Anodes consisting of titanium coated with oxides of ruthenium and titanium are placed in the brine without touching the mercury film. At the anodes, chlorine gas is formed which is collected and directed to further processing. Due to a high overpotential of hydrogen at the mercury electrode, no gaseous hydrogen is formed; instead, sodium is produced and dissolved in the mercury as an amalgam (mercury alloy). The liquid amalgam is removed from the electrolytic cell and fed to a decomposer, where it reacts with demineralised water in the presence of a graphite-based catalyst to form sodium hydroxide solution and hydrogen. The sodium-free mercury is recirculated back into the cell. Cooling of hydrogen is essential to remove any water and mercury. The sodium hydroxide solution is very pure, almost free from chloride contamination and has usually a concentration of 50 %. Further treatment comprises cooling and removal of catalyst and mercury traces by centrifuges or filters. Advantages of the mercury cell process are the high quality of chlorine and the high concentration and purity of sodium hydroxide solution produced. The consumption of electric energy for electrolysis is, however, higher than for the other techniques and a high purity of the feed brine is required. Inherently, the use of mercury gives rise to environmental releases of mercury. References: Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). technologyComment of potassium hydroxide production (RER): Potassium hydroxide is manufactured by the electrolysis of potassium chloride brine in electrolytical cells. Hydrogen and chlorine are withdrawn from the cell. The rest of the reaction mixture contains KOH, water, and unreacted potassium chloride. This reaction mixture is then concentrated in an evaporator. Most of the potassium chloride crystallizes by evaporation, and is recycled. After evaporation, the potassium hydroxide is precipitated. Potassium hydroxide, chlorine and hydrogen are obtained from potassium chloride brine according to the following reaction: 2 KCl + 2 H2O -> 2 KOH + Cl2 + H2 Reference: Jungbluth, N., Chudacoff, M., Dauriat, A., Dinkel, F., Doka, G., Faist Emmenegger, M., Gnansounou, E., Kljun, N., Schleiss, K., Spielmann, M., Stettler, C., Sutter, J. 2007: Life Cycle Inventories of Bioenergy. ecoinvent report No. 17, Swiss Centre for Life Cycle Inventories, Dübendorf, CH. technologyComment of sodium chloride electrolysis (RER): Sodium chloride electrolysis
| Organisation | Count |
|---|---|
| Bund | 130 |
| Europa | 1 |
| Kommune | 2 |
| Land | 3 |
| Weitere | 6 |
| Wissenschaft | 16 |
| Zivilgesellschaft | 6 |
| Type | Count |
|---|---|
| Chemische Verbindung | 35 |
| Förderprogramm | 43 |
| Gesetzestext | 27 |
| Text | 58 |
| Umweltprüfung | 1 |
| License | Count |
|---|---|
| Geschlossen | 39 |
| Offen | 45 |
| Unbekannt | 53 |
| Language | Count |
|---|---|
| Deutsch | 135 |
| Englisch | 5 |
| Resource type | Count |
|---|---|
| Archiv | 52 |
| Datei | 51 |
| Dokument | 54 |
| Keine | 73 |
| Webseite | 10 |
| Topic | Count |
|---|---|
| Boden | 84 |
| Lebewesen und Lebensräume | 86 |
| Luft | 52 |
| Mensch und Umwelt | 137 |
| Wasser | 72 |
| Weitere | 110 |