Description: 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
Types:
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Comment: This is a market activity. Each market represents the consumption mix of a product in a given geography, connecting suppliers with consumers of the same product in the same geographical area. Markets group the producers and also the imports of the product (if relevant) within the same geographical area. They also account for transport to the consumer and for the losses during that process, when relevant. This dataset represents the supply of 1 kg of chlorine, gaseous from activities that produce it within the geography RER. A regional market for Europe [RER] is motivated by the low share (in the range of 0.3%-2.9% of total trade quantities between 2010-2016) of import quantities to EU28 from outside (excluding Norway and Switzerland) the Union. Source: Eurostat database, EU trade since 1988 by HS6 (DS-016893), HS6-code: 280110 - CHLORINE, Assessed on: 2018-01-22. This product is generally considered to be used at the production site. Therefore, the market does not contain any transport. This market is supplied by the following activities with the given share: sodium chloride electrolysis, RER: 0.00404965612484565 chlor-alkali electrolysis, diaphragm cell, RER: 0.137484765319105 chlor-alkali electrolysis, membrane cell, RER: 0.647990211734413 chlor-alkali electrolysis, mercury cell, RER: 0.201431167793108 potassium hydroxide production, RER: 0.00904419902852849 generalComment of chlor-alkali electrolysis, diaphragm cell (RER): This dataset represents the production of chlorine and sodium hydroxide (NaOH) by means of chlor-alkali electrolysis using a diaphragm cell. The chlor-alkali process is the main technology for the production of chlorine and sodium hydroxide. In this process, chlorine and sodium hydroxide are produced by electrolysis of a salt solution using either a mercury cell, diaphragm cell or membrane cell. Chlorine is largely used in the synthesis of chlorinated organic compounds. PVC and isocyanates are the main drivers of chlor-alkali production in the EU-27 and EFTA countries (Euro Chlor 2013). These products are used in a wide range of applications, such as construction materials, plastics, clothing and pesticides. Sodium hydroxide is a white odorless pellet or solid that is very soluble. Sodium hydroxide is used for the synthesis of other chemicals, and is used in the metal industry, the pulp and paper sector, the textile industry and in other various sectors. This dataset is mainly based on a document concerning the best available techniques in the chlor-alkali manufacturing industry (European Commission 2001). References: Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. Final report ecoinvent data v2.0 No. 8. Swiss Centre for Life Cycle Inventories, Dübendorf, CH. European Commission (2001) Integrated Pollution Prevention and Control (IPPC) - Reference Document on Best Available Techniques in the Chlor-Alkali Manufacturing Industry. Institute for Prospective Technological Studies, Sevilla. Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). generalComment of chlor-alkali electrolysis, membrane cell (RER): This dataset represents the production of chlorine and sodium hydroxide (NaOH) by means of chlor-alkali electrolysis using a membrane cell. The chlor-alkali process is the main technology for the production of chlorine and sodium hydroxide. In this process, chlorine and sodium hydroxide are produced by electrolysis of a salt solution using either a mercury cell, diaphragm cell or membrane cell. Chlorine is largely used in the synthesis of chlorinated organic compounds. PVC and isocyanates are the main drivers of chlor-alkali production in the EU-27 and EFTA countries (Euro Chlor 2013). These products are used in a wide range of applications, such as construction materials, plastics, clothing and pesticides. Sodium hydroxide is a white odorless pellet or solid that is very soluble. Sodium hydroxide is used for the synthesis of other chemicals, and is used in the metal industry, the pulp and paper sector, the textile industry and in other various sectors. This dataset is mainly based on a document concerning the best available techniques in the chlor-alkali manufacturing industry (European Commission 2001). References: Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. Final report ecoinvent data v2.0 No. 8. Swiss Centre for Life Cycle Inventories, Dübendorf, CH. European Commission (2001) Integrated Pollution Prevention and Control (IPPC) - Reference Document on Best Available Techniques in the Chlor-Alkali Manufacturing Industry. Institute for Prospective Technological Studies, Sevilla. Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). generalComment of chlor-alkali electrolysis, mercury cell (RER): This dataset represents the production of chlorine and sodium hydroxide (NaOH) by means of chlor-alkali electrolysis using a mercury cell. The chlor-alkali process is the main technology for the production of chlorine and sodium hydroxide. In this process, chlorine and sodium hydroxide are produced by electrolysis of a salt solution using either a mercury cell, diaphragm cell or membrane cell. Chlorine is largely used in the synthesis of chlorinated organic compounds. PVC and isocyanates are the main drivers of chlor-alkali production in the EU-27 and EFTA countries (Euro Chlor 2013). These products are used in a wide range of applications, such as construction materials, plastics, clothing and pesticides. Sodium hydroxide is a white odorless pellet or solid that is very soluble. Sodium hydroxide is used for the synthesis of other chemicals, and is used in the metal industry, the pulp and paper sector, the textile industry and in other various sectors. This dataset is mainly based on a document concerning the best available techniques in the chlor-alkali manufacturing industry (European Commission 2001). References: Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. Final report ecoinvent data v2.0 No. 8. Swiss Centre for Life Cycle Inventories, Dübendorf, CH. European Commission (2001) Integrated Pollution Prevention and Control (IPPC) - Reference Document on Best Available Techniques in the Chlor-Alkali Manufacturing Industry. Institute for Prospective Technological Studies, Sevilla. Euro Chlor (2013) An Eco-profile and Environmental Product Declaration of the European Chlor-Alkali Industry, Chlorine (The chlor-alkali process). generalComment of potassium hydroxide production (RER): This dataset represents the production of 1 kg of pure potassium hydroxide (KOH), which is commercialized in the form of a 85.6% aqueous solution. Potassium hydroxide forms solid flakes at room temperature and is used primarily for the production of potassium phosphates, as well as potassium soaps and detergents. It is manufactured by the electrolysis of potassium chloride brine in electrolytical cells. This dataset is based on industrial as well as literature data. The original data is published in the ecoinvent report No. 17 (pg 702), that describes the production of 1 kg of 85.6% (~90%) pure KOH. The data in this report was scaled up to represent the product of interest. References: 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. generalComment of sodium chloride electrolysis (RER): Sodium is the best-known alkali metal. Sodium crystallizes from the melt with a body- centered cubic crystal lattice. It has typical metallic properties, including high thermal and electrical conductivity, the electrical conductivity of sodium at 20 °C being about one-third that of copper. It is liquid over a wide temperature range from 97.8 to 881.4 °C and has a fairly low vapor pressure, which is an important requirement for production in an electrolytic cell. Sodium can be obtained from many of its compounds by high-temperature reduction. In the older thermochemical methods, sodium carbonate or sodium hydroxide was reacted with charcoal or coal, sulfur, or iron. Other compounds of sodium, such as the chloride, sulfide, sulfate, and cyanide were also used. A serious disadvantage of thermochemical methods was that reverse and secondary reactions occurred. Despite these problems, patents were applied for, covering many variations of the thermochemical methods of production. In a Du Pont patent, sodium carbonate or sodium hydroxide was reduced with coal. The gases formed in the reaction were passed through molten tin, which absorbed the sodium vapor. Sodium was then recovered from the tin in an additional process step. According to a patent of Pechiney S. A., NaCl vapor is passed over calcium carbide at 800 – 1000 °C, and the sodium formed is collected in oil. In a Dow Chemical Co. process, sodium carbonate is reduced with coal at > 1200 °C. The sodium vapor formed is condensed in liquid sodium. Sodium is produced by an electrolysis of sodium chloride. Frischknecht R., Jungbluth N., Althaus H.-J., Doka G., Dones R., Heck T., Hellweg S., Hischier R., Nemecek T., Rebitzer G. and Spielmann M. (2007) Overview and Methodology. Final report ecoinvent v2.0 No. 1. Swiss Centre for Life Cycle Inventories, Dübendorf, CH, retrieved from: www.ecoinvent.org. Gendorf (2000) Umwelterklärung 2000, Werk Gendorf. Werk Gendorf, Burgkirchen as pdf-File under: http://www.gendorf.de/pdf/umwelterklaerung2000.pdf Alfred Klemm, Gabriele Hartmann, Ludwig Lange: Sodium and Sodium Alloys. Published online: 2003. In: Ullmann's Encyclopedia of Industrial Chemistry, Seventh Edition, 2004 Electronic Release (ed. Fiedler E., Grossmann G., Kersebohm D., Weiss G. and Witte C.). 7 th Electronic Release Edition. Wiley InterScience, New York, Online-Version under: DOI: 10.1002/14356007.a24_277
Origin: /Bund/UBA/ProBas
Tags: Kaliumchlorid ? Quecksilbergehalt ? Natriumchlorid ? Natriumhypochlorit ? Kalisalz ? Chloralkaliindustrie ? Aktivkohle ? Chlor ? Natriumhydroxid ? Ruthenium ? Titan ? Umweltproduktdeklaration ? Metalloxid ? Schweiz ? Katalysator ? Kühlwasser ? Quecksilber ? Chloralkali-Elektrolyse ? Stromversorgung ? Wasserdampf ? Wasserstoff ? Salz ? Flusswasser ? Bioenergie ? Verdunstung ? Futtermittel ? Wärme ? Wasserkühlung ? Elektrolyse ? Membranverfahren ? Dechlorierung ? Asbest ? Filter ? Ionen ? Sauerstoffgehalt ? Amalgam ? Gewässergrund ? Konsum ? Wasser ? Stahl ? Perkolation ? Energiebedarf ? Explosivstoff ? Niederschlag ? Rückstand ? Versickerung ? Investition ? Legierung ? Hang ? Manufacturing ? Manufacture of chemicals and chemical products ? Manufacture of basic chemicals, fertilizers and nitrogen compounds, plastics and synthetic rubber in primary forms ? Manufacture of basic chemicals ?
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