technologyComment of styrene production (RoW): Styrene is mainly produced by the dehydrogenation of ethylbenzene (EBS process) and via ethylbenzene hydroperoxide (POSM process) with propylene oxide as a by-product (James and Castor 2011). This dataset reflects only the dehydrogenation of ethylbenzene (EBS). Close to the entire production of ethylbenzene is produced via the alkylation of ethylene and benzene (Welch et al. 2005). This production route has been used since the mid-nineties (James and Castor 2011). Chemical reaction: C6H6 + C2H4 -> C8H10 C8H10 -> C8H8 + H2 The reaction from ethylbenzene to styrene is reversible. The reaction is endothermic with a heat delta of 600 degrees Celcius and 124.0 kJ/mol (James and Castor 2011). The production of styrene is mostly performed (ca. 75% of production), by running ethylbenzene (the input includes recycled ethylbenzene) through subsequent reactors / reactors beds. Steam is used to dehydrogenate the input product. Steam has been found to ensure a high yield, provide the necessary conditions for the reaction to happen and at the same time cleaning the used catalyst (James and Castor 2011). The use of a catalyst boosts the efficiency of the reaction, otherwise low temperature and low pressure are enough to ensure the reaction but with lower yield. Usual reaction conditions are 620 degrees Celsius combined with very low pressure, this ensures a yield between 88 and 95% (James and Castor 2011). According to James and Castor (2011) one of the most used catalyst for this reaction is composed by 84.3% iron (Fe2O3), 2.4% chromium (Cr2O3), and 13.3% potassium (K2CO3) (James and Castor 2011). The average lifespan of catalysts for this reaction is assumed to be 2 years (James and Castor 2011). The catalyst in not consider significant in terms of emissions for the reaction and it is therefore not included in this dataset and it is assumed to be taken into consideration in the input of chemical factory. The main source of information for the values for water (process and cooling), nitrogen and chemical factory is industry data from Gendorf. The values are a 5-year average of data (2011 - 2015) published by the Gendorf factory (Gendorf, 2016, Umwelterklärung, www.gendorf.de), (Gendorf, 2015, Umwelterklärung, www.gendorf.de), (Gendorf, 2014, Umwelterklärung, www.gendorf.de). The Gendorf factory is based in Germany, it produces a wide range of chemical substances. The factory produced 1657400 tonnes of chemical substances in the year 2015 (Gendorf, 2016, Umwelterklärung, www.gendorf.de) and 740000 tonnes of intermediate products. Reference(s): Hischier, R. (2005) Establishing Life Cycle Inventories of Chemicals Based on Differing Data Availability (9 pp). The International Journal of Life Cycle Assessment, Volume 10, Issue 1, pp 59–67. 10.1065/lca2004.10.181.7 Gendorf (2016) Umwelterklärung 2015, Werk Gendorf Industriepark, www.gendorf.de James, D.H. and Castor, W.M. 2011. Styrene. In Ullmann's Encyclopedia of Industrial Chemistry, Electronic Release, Vol.34, pp.529-544. Wiley-VCH, Weinheim. Welch, V.A. et al. 2005. Ethylbenzene. In Ullmann's Encyclopedia of Industrial Chemistry, Electronic Release, Vol.13, pp.451-464. Wiley-VCH, Weinheim. technologyComment of styrene production (RER): Styrene is mainly produced by the dehydrogenation of ethylbenzene (EBS process) and via ethylbenzene hydroperoxide (POSM process) with propylene oxide as a by-product (James and Castor 2011). This dataset reflects only the dehydrogenation of ethylbenzene (EBS). Close to the entire production of ethylbenzene is produced via the alkylation of ethylene and benzene (Welch et al. 2005). This production route has been used since the mid-nineties (James and Castor 2011). Chemical reaction: C6H6 + C2H4 -> C8H10 C8H10 -> C8H8 + H2 The reaction from ethylbenzene to styrene is reversible. The reaction is endothermic with a heat delta of 600 degrees Celcius and 124.0 kJ/mol (James and Castor 2011). The production of styrene is mostly performed (ca. 75% of production), by running ethylbenzene (the input includes recycled ethylbenzene) through subsequent reactors / reactors beds. Steam is used to dehydrogenate the input product. Steam has been found to ensure a high yield, provide the necessary conditions for the reaction to happen and at the same time cleaning the used catalyst (James and Castor 2011). The use of a catalyst boosts the efficiency of the reaction, otherwise low temperature and low pressure are enough to ensure the reaction but with lower yield. Usual reaction conditions are 620 degrees Celsius combined with very low pressure, this ensures a yield between 88 and 95% (James and Castor 2011). According to James and Castor (2011) one of the most used catalyst for this reaction is composed by 84.3% iron (Fe2O3), 2.4% chromium (Cr2O3), and 13.3% potassium (K2CO3) (James and Castor 2011). The average lifespan of catalysts for this reaction is assumed to be 2 years (James and Castor 2011). The catalyst in not consider significant in terms of emissions for the reaction and it is therefore not included in this dataset and it is assumed to be taken into consideration in the input of chemical factory. The main source of information for the values for water (process and cooling), nitrogen and chemical factory is industry data from Gendorf. The values are a 5-year average of data (2011 - 2015) published by the Gendorf factory (Gendorf, 2016, Umwelterklärung, www.gendorf.de), (Gendorf, 2015, Umwelterklärung, www.gendorf.de), (Gendorf, 2014, Umwelterklärung, www.gendorf.de). The Gendorf factory is based in Germany, it produces a wide range of chemical substances. The factory produced 1657400 tonnes of chemical substances in the year 2015 (Gendorf, 2016, Umwelterklärung, www.gendorf.de) and 740000 tonnes of intermediate products. Reference(s): Hischier, R. (2005) Establishing Life Cycle Inventories of Chemicals Based on Differing Data Availability (9 pp). The International Journal of Life Cycle Assessment, Volume 10, Issue 1, pp 59–67. 10.1065/lca2004.10.181.7 Gendorf (2016) Umwelterklärung 2015, Werk Gendorf Industriepark, www.gendorf.de James, D.H. and Castor, W.M. 2011. Styrene. In Ullmann's Encyclopedia of Industrial Chemistry, Electronic Release, Vol.34, pp.529-544. Wiley-VCH, Weinheim. Welch, V.A. et al. 2005. Ethylbenzene. In Ullmann's Encyclopedia of Industrial Chemistry, Electronic Release, Vol.13, pp.451-464. Wiley-VCH, Weinheim. Certain data points from a company survey by PlasticsEurope (three companies and four production sites).
technologyComment of ethylene oxide production (RER): Ethylene is directly oxidized with air or oxygen in the presence of a catalyst to ethylene oxide (EO). About 40% of all European EO production is converted into glycols, globally the figure is about 70%. Usually, EO and MEG are produced together at integrated plants. Industrial production started in 1937 with a union Carbide process based on ethylene and air. In 1958 oxygen rather than air was instroduced by Shell Development Company, and today most processes are based on oxygen. Total European production was 3.4 million tons per year in 1997, while the US produced 5.2 million tons per year. Further production capacity of at least 1.2 million tons is reported from Saudi Arabia, Kuwait, Japan and South Korea giving a total of at least 9.8 million tons of ethylene oxide production worldwide. Ethylene oxide is a hydrocarbon compound made from ethylene and oxygen. Major manufacturers include Hoechst Celanese, Shell Chemical, and Union Carbide, among many others. EO is produced by passing a mixture of ethylene and oxygen over a solid silver-containing catalyst. Selectivity is improved by the addition of chlorine compounds such as chloroethane. Reaction conditions are temperatures of about 200 - 300 °C and a pressure of 10 – 30 bar. The main by-products are carbon dioxide and water, formed when ethylene is fully oxidised or some of the EO is further oxidised. Ethylene glycols are formed when the reactor gases are absorbed into chilled water. C2H4 + 1/2 O2 C2H4O (1) C2H4 O + H2O HO-C2H4-OH (2) C2H4 + 3 O2 2 CO2 + 2 H2O (3) (1) production of ethylene oxide (2) production of MEG from EO and water (3) production of carbon dioxide and water from oxidation of ethylene The carbon dioxide is removed from the scrubber by absorption with hot aqueous potassium carbonate, the resulting solution is steam stripped to remove the carbon dioxide, which is vented to air. The potassium carbonate is regenerated. The carbon dioxide can be reused for inerting, or is sold, or is vented to atmosphere. References: IPPC Chemicals, 2002. European Commission, Directorate General, Joint Research Center, “Reference Document on Best Available Techniques in the Large Volume Organic Chemical Industry”, February 2002. Wells, 1999. G. Margaret Wells, “Handbook of Petrochemicals and Processes”, 2nd edition, Ashgate, 1999
technologyComment of Mannheim process (RER): Production of sodium sulfate and HCl by the Mannheim process. This process can be summarized with the following overall stoechiometric reaction: 2 NaCl + H2SO4 → Na2SO4 + 2 HCl technologyComment of allyl chloride production, reaction of propylene and chlorine (RER): based on industry data in the US and Europe technologyComment of benzene chlorination (RER): Clorobenzenes are prepared by reaction of liquid benzene with gaseous chlorine in the presence of a catalyst at moderate temperature and atmospheric pressure. Hydrogen chloride is formed as a by-product. Generally, mixtures of isomers and compounds with varying degrees of chlorination are obtained, because any given chlorobenzene can be further chlorinated up to the stage of hexa-chlorobenzene. Because of the directing influence exerted by chlorine, the unfavoured products 1,3-dichlorobenzene, 1,3,5-trichlorobenzene and 1,2,3,5-tetrachlorobenzene are formed to only a small extent if at all. The velocity of chlorination for an individual chlorine compound depends on the compound's structure and, because of this, both the degree of chlorination and also the isomer ratio change continuously during the course of reaction. Sets of data on the composition of products from different reactions are only comparable if they refer to identical reaction conditions and materials having the same degree of chlorination. By altering the reaction conditions and changing the catalyst, one can vary the ratios of different chlorinated products within certain limits. Lewis acids (FeCl3, AlCl3, SbCl3, MnCl2, MoCl2, SnCl4, TiCl4) are used as principal catalysts. The usual catalyst employed in large scale production is ferric chloride, with or without the addition of sulfur compounds. The ratio of resulting chlorobenzenes to one another is also influenced by the benzene:chlorine ratio. For this reason, the highest selectivity is achieved in batch processes. If the same monochlorobenzene:dichlorobenzene ratio expected from a batch reactor is to result from continuous operation in a single-stage reactor, then a far lower degree of benzene conversion must be accepted as a consequence of the low benzene:chlorine ratio). The reaction is highly exothermic: C6H6 + Cl2 --> C6H5Cl + HCl ; delta H = -131.5 kJ/mol Unwanted heat of reaction can be dissipated either by circulating some of the reactor fluid through an external heat exchanger or by permitting evaporative cooling to occur at the boiling temperature. Circulation cooling has the advantage of enabling the reaction temperature to be varied in accordance with the requirements of a given situation. Evaporative cooling is more economical, however. Fractional distillation separates the products. Iron catalyst is removed with the distillation residue.Unreacted benzene is recycled to the reactor. technologyComment of hydrochloric acid production, from the reaction of hydrogen with chlorine (RER): HCl can be either directly prepared or generated as a by-product from a number of reactions. This dataset represents the production of HCl via the combustion of chlorine with hydrogen gas. The process involves burning hydrogen gas and chlorine in a gas combustion chamber, producing hydrogen chloride gas. The hydrogen chloride gas then passes through a cooler to an absorber where process water is introduced, producing aqueous hydrochloric acid. H2 + Cl2 -> 2 HCl (exothermic reaction) References: Althaus H.-J., Chudacoff M., Hischier R., Jungbluth N., Osses M. and Primas A. (2007) Life Cycle Inventories of Chemicals. ecoinvent report No. 8, v2.0. EMPA Dübendorf, Swiss Centre for Life Cycle Inventories, Dübendorf, CH. technologyComment of tetrafluoroethylene production (RER): The production of fluorochemicals and PTFE monomers can be summarized with the following chemical reactions (Cedergren et al. 2001): CaF2 + H2SO4 -> CaSO4 + 2HF (1) CH4 + 3Cl2 -> CHCl3 + 3HCl (2) CHCl3 + 2HF -> CHClF2 + 2HCl (3) 2 CHClF2 + heat -> CF2=CF2 + 2 HCl (4) This dataset represents the last reaction step (4). Parts of the production are carried out at high pressure and high temperature, 590 ºC – 900 ºC. The first reaction (1) takes place in the presence of heat and HSO3 - and steam. The inventory for the production of hydrogen fluoride can be found in the report (Jungbluth 2003a). Reaction (2) is used to produce trichloromethane. Reaction 3 for the production of chlorodifluoromethane takes place in the presence of a catalyst. The production of PTFE (4) takes place under high temperature pyrolysis conditions. Large amounts of hydrochloric acid (HCl) are generated as a couple product during the process and are sold as a 30% aqueous solution. A large number of other by-products and emissions is formed in the processes (benzene, dichloromethane, ethylene oxide, formaldehyde, R134a, and vinyl chloride) and small amounts of the highly toxic perfluoroisobutylene CF2=C(CF3)2. The by-products in the production of monomers can harm the processes of polymerisation. Because of this, the refinement of the production of monomers has to be very narrow. This makes the process complex and it contributes to a high cost for the PTFE-laminates. (Cedergren et al. 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.
technologyComment of hydroformylation of propylene (RER, RoW): In the oxo reaction (hydroformylation), carbon monoxide and hydrogen are added to a carbon – carbon double bond in the liquid phase in the presence of catalyst (hydrocarbonyls or substituted hydrocarbonyls of Co, Rh, or Ru). In the first reaction step aldehydes are formed with one more C-atom than the original olefins. For olefins with more than two C-atoms, isomeric aldehyde mixtures are normally obtained. In the case of propylene these consist of 1-butanal and 2-methylpropanal. imageUrlTagReplace600920a3-5103-4466-9c05-fd1d8ed0d89c There are several variations of the hydroformylation process, the differences being in the reaction conditions (pressure, temperature) as well as the catalyst system used. The classic high-pressure process exclusively used until the beginning of the 1970s operates at pressures of 20 – 30 MPa (200 – 300 bar) CO/H2 and temperatures of 100 – 180 °C. The catalyst is Co. It leads to about 75 % 1-butanol and about 25 % 2-methyl-1-propanol. The new process developments of the past few years have led to a clear shift in the range of products. The processes operating at relatively low pressures (1 – 5 MPa , 10 – 50 bar) use modified Rh-catalysts. The isomeric ratios achieved are about 92 : 8 or 95 : 5 1-butanol to 2-methyl-1-propanol. However, by the use of unmodified Rh the percentage of 2-methyl-1-propanol can be increased to about 50 %. Catalytic hydrogenation of the aldehydes leads to the formation of the corresponding alcohols. As only primary alcohols can be obtained via the oxo synthesis, it is not possible to produce 2-butanol and 2-methyl-2-propanol by this process. Reference: Hahn, H., Dämkes, G., Ruppric, N.: Butanols. In: Ullmann's Encyclopedia of In-dustrial 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: http://www.mrw.interscience.wiley.com/ueic/articles/ technologyComment of synthetic fuel production, from coal, high temperature Fisher-Tropsch operations (ZA): SECUNDA SYNFUEL OPERATIONS: Secunda Synfuels Operations operates the world’s only commercial coal-based synthetic fuels manufacturing facility of its kind, producing synthesis gas (syngas) through coal gasification and natural gas reforming. They make use of their proprietary technology to convert syngas into synthetic fuel components, pipeline gas and chemical feedstock for the downstream production of solvents, polymers, comonomers and other chemicals. Primary internal customers are Sasol Chemicals Operations, Sasol Exploration and Production International and other chemical companies. Carbon is produced for the recarburiser, aluminium, electrode and cathodic production markets. Secunda Synfuels Operations receives coal from five mines in Mpumalanga (see figure attached). After being crushed, the coal is blended to obtain an even quality distribution. Electricity is generated by both steam and gas and used to gasify the coal at a temperature of 1300°C. This produces syngas from which two types of reactor - circulating fluidised bed and Sasol Advanced SynthoTM reactors – produce components for making synthetic fuels as well as a number of downstream chemicals. Gas water and tar oil streams emanating from the gasification process are refined to produce ammonia and various grades of coke respectively. imageUrlTagReplacea79dc0c2-0dda-47ec-94e0-6f076bc8cdb6 SECUNDA CHEMICAL OPERATIONS: The Secunda Chemicals Operations hub forms part of the Southern African Operations and is the consolidation of all the chemical operating facilities in Secunda, along with Site Services activities. The Secunda Chemicals hub produces a diverse range of products that include industrial explosives, fertilisers; polypropylene, ethylene and propylene; solvents (acetone, methyl ethyl ketone (MEK), ethanol, n-Propanol, iso-propanol, SABUTOL-TM, PROPYLOL-TM, mixed C3 and C4 alcohols, mixed C5 and C6 alcohols, High Purity Ethanol, and Ethyl Acetate) as well as the co-monomers, 1-hexene, 1-pentene and 1-octene and detergent alcohol (SafolTM).
technologyComment of cyclohexane production (RER, RoW): Over 90 % of all cyclohexane is produced commercially by hydrogenation of benzene. A small amount is produced by superfractionation of the naphtha fraction from crude oil. Naturally occurring cyclohexane can be supplemented by fractionating methylcyclopentane from naphtha and isomerizing it to cyclohexane. Hydrogenation of benzene: Benzene can be hydrogenated catalytically to cyclohexane in either the liquid or the vapor phase in the presence of hydrogen. Several cyclohexane processes, which use nickel, platinum, or palladium as the catalyst, have been developed. Usually, the catalyst is supported, e.g., on alumina, but at least one commercial process utilizes Raney nickel. Hydrogenation proceeds readily and is highly exothermic (Δ H500K = – 216.37 kJ/mol). From an equilibrium standpoint, the reaction temperature should not exceed 300 °C. Above this, the equilibrium begins to shift in favor of benzene so that high-purity cyclohexane cannot be produced. As a result of these thermodynamic considerations, temperature control of the reaction is critical to obtaining essentially complete conversion of benzene to cyclohexane. Temperature control requires economic and efficient heat removal. This has been addressed in a number of ways by commercial processes. The earlier vapor-phase processes used multistage reactors with recycle of cyclohexane as a diluent to provide a heat sink, staged injection of benzene feed between reactors, and interstage steam generators to absorb the exothermic heat of hydrogenation. In the 1970s processes have been developed that use only one reactor or a combination of a liquid-and a vaporphase reactor. The objectives of the later processes were to reduce capital cost and improve energy utilization. However, all of the commercial processes have comparably low capital cost and good energy efficiency. In the vapor-phase process with multistage reactors in series, the benzene feed is divided and fed to each of the first two reactors. Recycled cyclohexane is introduced to the first reactor along with hydrogen. The recycled cyclohexane enables higher conversion in the reactors by absorbing part of the heat of hydrogenation. Steam generators between the reactors remove the heat of hydrogenation. The outlet temperature of the last reactor is controlled to achieve essentially 100 % conversion of benzene to cyclohexane. The effluent from the last reactor is cooled, and the vapor and liquid are separated. Part of the hydrogen-rich vapor is recycled to the first reactor, and the rest is purged to fuel gas or hydrogen recovery facilities. The liquid from the separator goes to a stabilizer where the overhead gas is sent to fuel gas; the remaining material is cyclohexane product, part of which is recycled to the first reactor. In the process with liquid- and vapor-phase reactors, benzene and hydrogen are fed to the liquid-phase reactor, which contains a slurry of finely divided Raney nickel. Temperature is maintained at 180 – 190 °C by pumping the slurry through a steam generator and by vaporization in the reactor. Roughly 95 % of the benzene is converted in this reactor. The vapor is fed to a fixed-bed reactor where the conversion of benzene is completed. The effluent from the fixed-bed reactor is processed as described previously for the vapor-phase process. Benzene hydrogenation is done typically at 20 – 30 MPa. The maximum reactor temperature is limited to ca. 300 °C so that a typical specification of < 500 mg/kg benzene and < 200 mg/kg methylcyclopentane in the product can be achieved. This is necessary because of the thermodynamic equilibrium between cyclohexane – benzene and cyclohexane – methylcyclopentane. Actually, equilibrium strongly favors methylcyclopentane, but the isomerization reaction is slow enough with the catalysts employed to avoid a problem if the temperature is controlled. The hydrogen content of the makeup hydrogen has no effect on product purity but it does determine the makeup, recycle, and purge gas rates. Streams with as low as 65 vol % hydrogen can be used. Carbon monoxide and sulfur compounds are catalyst deactivators. Both can be present in the hydrogen from catalytic naphtha reformers or ethylene units, which are typical sources of makeup hydrogen. Therefore, the hydrogen-containing stream is usually passed through a methanator to convert carbon monoxide to methane and water. Prior to methanation, hydrogen-containing gas can be scrubbed with caustic to remove sulfur compounds. Commercial benzene contains less than 1 mg/kg sulfur. In some cases, the recycle gas is also scrubbed with caustic to prevent buildup of hydrogen sulfide from the small amount of sulfur in the benzene. With properly treated hydrogen and specification benzene, a catalyst life in excess of three years can be achieved easily in fixed-bed reactors that use noble-metal catalysts supported on a base. The catalyst in the process that uses Raney nickel in suspension is reported to have a typical life of about six months before it must be replaced. Reference: Campbell, M. L. 2011. Cyclohexane. Ullmann's Encyclopedia of Industrial Chemistry.
technologyComment of ammonia production, steam reforming, liquid (RER w/o RU): This datasets corresponds to the technology used in European ammonia plants with natural gas based fuel and feedstock. The most efficient way of ammonia synthesis gas production is natural gas reforming with steam and air. The ammonia production process consists of several steps: desulphurization, primary production, secondary reforming, shift conversion, CO2 removal, methanation, synthesis gas compression and ammonia synthesis. technologyComment of ammonia production, steam reforming, liquid (RU): This datasets corresponds to the technology used in Russian ammonia plants with natural gas based fuel and feedstock. The most efficient way of ammonia synthesis gas production is natural gas reforming with steam and air. The ammonia production process consists of several steps: desulphurization, primary production, secondary reforming, shift conversion, CO2 removal, methanation, synthesis gas compression and ammonia synthesis. technologyComment of cocamide diethanolamine production (RER): Cocamide diethanolamine can be produced from different reaction of diethanolamine with methyl cocoate, coconut oil, whole coconut acids, stripped coconut fatty acids. Cocamide diethanolamine is modelled here as the 1:1 reaction of coconut oil and diethanolamine. The reaction occurs at a maximum temperature of 170 degrees Celcius with the aid of an alkaline catalyst. The catalyst in not consider significant in terms of emissions for the reaction and it is therefore not included in this dataset and it is assumed to be taken into consideration in the input of chemical factory. The production process can also be a 1:2 fatty acids reaction. This results in a lower quality product with output of free diethanolamine and ethylene glycol (Elbers 2013). Coconut oil composition varies, here it assumed an average composition CH3(CH2)12CONH2. This inventory representing production of a particular chemical compound is at least partially based on a generic model on the production of chemicals. The data generated by this model have been improved by compound-specific data when available. The model on production of chemicals is using specific industry or literature data wherever possible and more generic data on chemical production processes to fill compound-specific data gaps when necessary. The basic principles of the model have been published in literature (Hischier 2005, Establishing Life Cycle Inventories of Chemicals Based on Differing Data Availability). The model has been updated and extended with newly available data from the chemical industry. In the model, unreacted fractions are treated in a waste treatment process, and emissions reported are after a waste treatment process that is included in the scope of this dataset. For volatile reactants, a small level of evaporation is assumed. Solvents and catalysts are mostly recycled in closed-loop systems within the scope of the dataset and reported flows are for losses from this system. The main source of information for the values for heat, electricity, water (process and cooling), nitrogen, chemical factory is industry data from Gendorf. The values are a 5-year average of data (2011 - 2015) published by the Gendorf factory (Gendorf, 2016, Umwelterklärung, www.gendorf.de), (Gendorf, 2015, Umwelterklärung, www.gendorf.de), (Gendorf, 2014, Umwelterklärung, www.gendorf.de). The Gendorf factory is based in Germany, it produces a wide range of chemical substances. The factory produced 1657400 tonnes of chemical substances in the year 2015 (Gendorf, 2016, Umwelterklärung, www.gendorf.de) and 740000 tonnes of intermediate products. Reference(s): Hischier, R. (2005) Establishing Life Cycle Inventories of Chemicals Based on Differing Data Availability (9 pp). The International Journal of Life Cycle Assessment, Volume 10, Issue 1, pp 59–67. 10.1065/lca2004.10.181.7 Gendorf (2016) Umwelterklärung 2015, Werk Gendorf Industriepark, www.gendorf.de Elbers, E. 2013. Some Chemicals Present in Industrial and Consumer Products, Food and Drinking-water. In IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC RISKS TO HUMANS, Vol.101, pp.141-148 WHO Press, Geneva. For more information on the model please refer to the dedicate ecoinvent report, access it in the Report section of ecoQuery (http://www.ecoinvent.org/login-databases.html)
EDC is produced industrially by the chlorination of ethylene, either directly with chlorine or by using hydrogen chloride (HCl). In practice, both routes are carried out together, the HCl stems from the cracking of EDC to vinyl chloride. HCl from other processes can also be used. The major outlet is for the production of vinyl chloride monomer (VCM). There are both integrated EDC / VCM plants as well as stand-alone EDC plants. In 1997, European production of EDC was 9.4 million tons, according to (IPPC Chemicals, 2002). This makes it Europe’s most produced halogenated product. Global demand is expected to grow at roughly 6% per year in the short run, while future growth depends on the global demand for PVC. Major plants with capacities greater than 600’000 tons per year are located in Belgium, France, the Netherlands, Italy, Norway, the US, Canada, Brazil, Saudi Arabia, Japan and Taiwan. Available data from production sites often refer to the entire EDC/VCM chain and do not differentiate between the production lines. There is some information on stand-alone sites, however, and this data forms the basis for part of the inventory developed in this report. EDC can be produced by two routes, both involving the chlorination of ethylene. One route involves direct chlorination, the other is carried out with hydrochloric acid (HCl) and oxygen. In practice, both routes are carried out together. This study includes an average of the available literature data from both routes. EDC by direct chlorination of ethylene: C2H4 + Cl2 C2H4Cl2 Yield on ethylene 96-98% / on chlorine 98% Liquid chlorine and pure ethylene are reacted in the presence of a catalyst (ferric chloride). The chlorination reaction can be carried out at low or high temperature. In the low-temperature process takes place at 20 ºC – 70 ºC. The reaction is exothermic and heat exchangers are needed. The advantage of this process is that there are few by-products. The high-temperature process takes place at 100 ºC – 150 ºC. The heat generated is used to distill the EDC, which conserves energy. the reaction product consists of more than 99% EDC, the rest being chlorinated hydrocarbons that are removed with the light ends and then combusted or sold. EDC by direct chlorination of ethylene: C2H4 + Cl2 C2H4Cl2 Yield on ethylene 96-98% / on chlorine 98% Liquid chlorine and pure ethylene are reacted in the presence of a catalyst (ferric chloride). The chlorination reaction can be carried out at low or high temperature. In the low-temperature process takes place at 20 ºC – 70 ºC. The reaction is exothermic and heat exchangers are needed. The advantage of this process is that there are few by-products. The high-temperature process takes place at 100 ºC – 150 ºC. The heat generated is used to distill the EDC, which conserves energy. Tthe reaction product consists of more than 99% EDC, the rest being chlorinated hydrocarbons that are removed with the light ends and then combusted or sold. EDC by chlorination and oxychlorination: C2H4 + Cl2 C2H4Cl2 (1) C2H4 + 1/2 O2 + 2HCl C2H4Cl2 + H2O (2) Yield on ethylene 93-97% / on HCl 96-99% Pure ethylene and hydrogen chloride are heated and mixed with oxygen. The reaction occurs at 200 ºC – 300 ºC at 4-6 bar in the presence of a catalyst (cupric chloride). After reaction the gases are quenched with water. The acid and water are removed, the gases are cooled and the organic layer is washed and dried. If air is used instead of oxygen, the reaction is easier to control. However, oxygen-based processes operate at lower temperatures, reducing vent gas volume. By-products are ethyl chloride, 1,1,2-trichloromethane and chloral (trichloroacetaldehyde). Thermal cracking of EDC: Thermal cracking of dry, pure EDC produces VCM and HCl. Often all the HCl generated in the cracking section is reused in producing EDC by oxychlorination. Plants that exhibit this characteristic and also do not export EDC are called “balanced”. The balanced process is the common process used as a Best Available Technology benchmark. C2H4 + Cl2 C2H4Cl2 (Chlorination of ethylene to EDC) C2H4Cl CH2CHCl + HCl (Cracking of EDC to form VCM) C2H4 + 1/2 O2 + 2HCl C2H4Cl2 + H2O (Oxychlorination route to EDC) Reference: IPPC Chemicals, 2002 European Commission, Directorate General, Joint Research Center, “Reference Document on Best Available Techniques in the Large Volume Organic Chemical Industry”, February 2002 Wells, 1999 G. Margaret Wells, “Handbook of Petrochemicals and Processes”, 2nd edition, Ashgate, 1999
Drug therapy for diabetes mellitus has increased significantly in recent years. 1,1-Dimethylbiguanide hydrochloride (metformin) is the most common drug used for the treatment of diabetes. Metformin is not metabolized in the human body and enters the water cycle via sewage. A new gas chromatography-mass spectrometry (GC-MS) method has been developed which enables the quantification of metformin in surface water samples even at low concentrations in the ng L-1 range. A solid phase extraction (SPE) method for the preconcentration of metformin and the internal standard 1-butylbiguanide (buformin) was established, and the method parameters such as the composition and volume of the eluent were optimized. Derivatization of metformin and buformin was obtained by using n-methyl-bis (trifluoroacetamide) (MBTFA). The reaction conditions of the derivatization, such as the reaction temperature and volume of the derivatization agent, were evaluated. The limit of detection (LOD) and limit of quantification (LOQ) were determined to be 3.9 ng L-1 and 12 ng L-1 in surface water samples. Linearity was shown over a concentration range of 10-50 ng L-1. The good performance of the method was demonstrated by comparison with a liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The results indicate that the GC-MS method is a reliable and sensitive alternative for the quantification of metformin in surface water. Quelle: http://pubs.rsc.org
The heterogeneous hydrolysis of N2O5 on the surface of deliquescent aerosol leads to HNO3 formation and acts as a major sink of NOx in the atmosphere during night-time. The reaction constant of this heterogeneous hydrolysis is determined by temperature (T), relative humidity (RH), aerosol particle composition, and the surface area concentration (S). However, these parameters were not comprehensively considered in the parameterization of the heterogeneous hydrolysis of N2O5 in previous mass-based 3-D aerosol modelling studies. In this investigation, we propose a sophisticated parameterization (NewN2O5) of N2O5 heterogeneous hydrolysis with respect to T, RH, aerosol particle compositions, and S based on laboratory experiments. We evaluated closure between NewN2O5 and a state-of-the-art parameterization based on a sectional aerosol treatment. The comparison showed a good linear relationship (R?=??0.91) between these two parameterizations. NewN2O5 was incorporated into a 3-D fully online coupled model, COSMOŃMUSCAT, with the mass-based aerosol treatment. As a case study, we used the data from the HOPE Melpitz campaign (10Ń25 September 2013) to validate model performance. Here, we investigated the improvement of nitrate prediction over western and central Europe. The modelled particulate nitrate mass concentrations ([NO3-]) were validated by filter measurements over Germany (Neuglobsow, Schmücke, Zingst, and Melpitz). The modelled [NO3-] was significantly overestimated for this period by a factor of 5Ń19, with the corrected NH3 emissions (reduced by 50?%) and the original parameterization of N2O5 heterogeneous hydrolysis. The NewN2O5 significantly reduces the overestimation of [NO3-] by ?~??35?%. Particularly, the overestimation factor was reduced to approximately 1.4 in our case study (12, 17Ń18 and 25 September 2013) when [NO3-] was dominated by local chemical formations. In our case, the suppression of organic coating was negligible over western and central Europe, with an influence on [NO3-] of less than 2?% on average and 20?% at the most significant moment. To obtain a significant impact of the organic coating effect, N2O5, SOA, and NH3 need to be present when RH is high and T is low. However, those conditions were rarely fulfilled simultaneously over western and central Europe. Hence, the organic coating effect on the reaction probability of N2O5 may not be as significant as expected over western and central Europe. Quelle: https://www.atmos-chem-phys.net/
Landesanstalt für Umweltschutz Baden-Württemberg Freisetzung von Phosphorwasserstoff bei der Oberflächenreinigung von Aluminiumteilen Dipl.-Chem. Hubert Faller Dipl.-Ing. (FH) Gerhard Ott OChR Ulrich Wurster* *Korrespondenzadresse: Landesanstalt für Umweltschutz Baden-Württemberg Referat Arbeitsschutz/Chemikalien Postfach 210752 76157 Karlsruhe Landesanstalt für Umweltschutz Baden-Württemberg Referat Arbeitsschutz/Chemikalien Postfach 210752 76157 Karlsruhe 2 Freisetzung von Phosphorwasserstoff bei der Oberflächenreinigung von Aluminiumteilen Zusammenfassung Die Entstehung von Phosphorwasserstoff (Phosphin , PH3) in relevanten Konzentrationen aus phosphathaltiger alka- lischer Reinigungslösung bei der Reinigung von Alumini- umteilen in einer handelsüblichen Industriespülmaschine unter üblichen Betriebsbedingungen konnte nachgewie- sen werden. Im stark alkalischen Milieu wird offenbar Phosphat des Reinigers im Kontakt mit Aluminium reduziert. Die für Phosphorwasserstoff existierende Maximale Ar- beitsplatz Konzentration (MAK-Wert) von 0,15 mg/m³ (0,1 ppm) kann hierbei zeitweise überschritten werden – ent- sprechende Arbeitsschutzmaßnahmen sind deshalb zu beachten. 1 Einleitung Beim Entladen einer Spülmaschine, die zur Reinigung von Aluminiumblechen eingesetzt wurde, klagte der Maschi- nenbediener über starkes Unwohlsein mit Schwindelgefühl und Atembeschwerden. Es wurde eine intensivmedizini- sche Behandlung nötig und ein ”Reizgasinhalationstrau- ma” diagnostiziert. Mitarbeiter hatten schon vor diesem Unfallereignis mehr- fach über einen carbidähnlichen Geruch (nach Knoblauch) beim Betrieb der Spülmaschine berichtet - ein Zusammen- hang mit einer möglichen Entwicklung von Phosphorwas- serstoff während des Reinigungsvorganges wurde jedoch zunächst nicht in Betracht gezogen. Aufgrund des auch bei dem Arbeitsunfall deutlich wahr- nehmbaren Geruches sollte auf Anforderung des zu- ständigen Staatlichen Gewerbeaufsichtsamtes durch Untersuchungen der Landesanstalt für Umweltschutz Ba- den-Württemberg (LfU) geklärt werden, ob bei dem ange- wendeten Oberflächenreinigungsprozess unter den übli- chen Betriebsbedingungen (Aluminiumbleche, alkalischer Phosphatreiniger, Temperatur ca. 60 °C) möglicherweise eine Freisetzung von PH3 (oder anderer Gefahrstoffe) statt- gefunden haben könnte. 2 Toxikologie von Phosphorwasserstoff Phosphorwasserstoff ist in die Kategorie I der lokal rei- zenden Stoffe eingeteilt, so dass der MAK-Wert von 0,1 ppm zu keinem Zeitpunkt überschritten werden soll (Über- schreitungsfaktor =1=) [1]. Phosphorwasserstoff ist ein hochgiftiges Gas mit Wir- kung auf wichtige Zellenzyme („Stoffwechselgift“), das bei akuter Vergiftung unter den Anzeichen der inneren Ersti- ckung zum Tode führen kann. Nach Inhalation ist ein to- xisches Lungenödem möglich. Dabei treten bei mittle- ren Konzentrationen (10 bis 100 ppm; Expositionszeit 0,5 bis 1 h) meist erst nach Stunden Vergiftungserschei- nungen auf. Bei Expositionszeiten von sechs Stunden sind schon 7 ppm wirksam. LfU Eine chronische Vergiftung ist nicht möglich, da im Orga- nismus üblicherweise eine Entgiftung kleiner Konzentrati- onen bis 2,5 ppm erfolgt [2]. Die Geruchsschwelle für die Phosphorwasserstoffwahr- nehmung liegt mit ca. 0,02 ppm [4] unter dem derzeit gülti- gen MAK-Wert von 0,1 ppm. 3 Beschreibung des Reinigungsverfahren Die Reinigung von Aluminiumblechen erfolgt im vorlie- genden Fall in einer handelsüblichen Industriespülma- schine. Die Reinigungslösung wird aus einem Spültank bei einer Solltemperatur von 55 bis 60 °C über 18 Düsen von unten auf die zu reinigendem Teile sprüht. Das Reini- gungsprogramm dauert fünf Minuten, wobei in der letzten Minute das Spülgut mit demineralisiertem Wasser nach- gespült wird. Ein Nachdosieren des Reinigerkonzentrates ist nach jedem Spülprozess erforderlich, da ein Teil des Spültankinhaltes während der Nachspülphase durch das demineralisierte Wasser ersetzt wird. Eine Dosiereinrich- tung soll gewährleisten, dass die empfohlene Konzentra- tion des Reinigerkonzentrates von ca. 4 g/l bei allen Spül- vorgängen in der Reinigungslösung konstant bleibt. Damit wird ein mittlerer pH-Wert von 10,8 erreicht (Mittelwert der Messwerte aus neun Spülvorgängen). Die Zusammensetzung des unverdünnten Reinigerkon- zentrats laut Sicherheitsdatenblatt ist in Tabelle 1 wieder- gegeben. Tabelle 1: Zusammensetzung eines Reinigerkonzentrats Stoff Anteil in Gew.-% Kaliumhydroxid1–5 Phosphate15 – 30 Alkalisilikate> 10 Amphotere Tenside<5 pH-Wert14 Die zu reinigenden Aluminiumbleche bestehen aus den Legierungen AlMg1 und AlMg3 eingesetzt, die sich im we- sentlichen durch ihren Anteil von ca. 1 bzw. 3 Gew.-% Ma- gnesium unterscheiden. Der Summenanteil anderer Ele- mente (somit auch der Gehalt an Phosphor) ist mit < 0,05 Gew.-% spezifiziert. 4 Phosphorwasserstoff- Entstehung 4.1 Phosphorquelle Für eine potenzielle Phosphorwasserstoff-Freisetzung in der Industriespülmaschine war zunächst die Herkunft des Phosphors zu klären. Bei einer typischen Beladung der Spülmaschine mit 30 Aluminiumblechen (Masse ca. 230 g; Oberfläche ca. 80 cm²) ergibt sich eine Gesamtmasse von LfU Freisetzung von Phosphorwasserstoff bei der Oberflächenreinigung von Aluminiumteilen ca. 6,9 kg. Darin können entsprechend der Spezifikation max. 3,5 g Phosphor enthalten sein, die jedoch nur zu ei- nem kleinen Teil (an der Blechoberfläche) für eine Reakti- on zur Verfügung stehen können. Bei einer gemessenen Aluminiumkonzentration von max. 10 mg/l in der Reinigungslösung (ca. 80 l) dürf- ten insgesamt nur ca. 0,4 mg Phosphor aus den Aluminiumblechen gelöst worden sein. Bei einer Reinigerkonzentration von ca. 4 g/l in der Rei- nigungslösung ergibt sich aus dem Gehalt an Phospha- ten eine Sollkonzentration von ca. 0,2 g/l Phosphor in der Reinigungslösung. In einer Maschinenfüllung dieser Rei- nigungslösung liegt somit eine Phosphormenge von 16 g vor. Dieser Phosphor steht für Reaktionen zur Verfügung und wird ständig nachdosiert – die dominierende Phos- phorquelle während des Spülprozesses ist demnach das Phosphat aus dem Reiniger. 4.2 Redoxreaktion Als starkes Reduktionsmittel für die Reduktion von Phos- phat zu Phosphorwasserstoff kommt Wasserstoff (”in sta- tu nascendi”) in Frage, der aus der Reaktion von Alumini- um mit der Reinigungslösung bei hohem pH-Wert stammt. Da bei kleinen wie bei hohen pH-Werten die Oxidschutz- schicht des Aluminiums nicht beständig ist, wird Alumini- um bei alkalischen Bedingungen unter Wasserstoffent- wicklung als Aluminat gelöst [1; 4; 5]. Nur im Bereich von 3 4,5 < pH < 8,5 ist die schützende Schutzschicht weitge- hend unlöslich (sieheBild 1). Wesentliche Faktoren für die Reaktion dürften aber, neben Reaktionszeit, pH-Wert und Konzentration von Fremdio- nen [6], die Reaktionstemperatur sein, da Phosphorwas- serstoff in einer endothermen Reaktion gebildet wird [4]. Bei pH-Werten im alkalischen Bereich kann durch Zusatz von Inhibitoren (z.B.: Alkalisilikate) der Angriff gehemmt werden [7]. In Bild 1 ist für die üblichen Betriebsbedingungen (pH ? 11; Temperatur ca. 60 °C; Aluminiumkonzentration in der Reinigungslösung von ca. 3,5 mg/l) die überschlägig er- mittelte flächenbezogene Massenverlustrate des Reini- gungsprozesses aufgetragen. Der Punkt liegt oberhalb des eingezeichneten Kurvenastes, da bei erhöhter Tem- peratur gearbeitet wird. 4.3 MAK-Wert-Überschreitung: Zum Erreichen des für Phosphorwasserstoff festgeleg- ten MAK-Wertes von 0,1 ppm im nur ca. 0,4 m³ großen Spülraum der Maschine sind nur 0,06 mg PH3 erforder- lich. Ein Vergleich mit der tatsächlichen in der Reinigungs- lösung vorhandenen Phosphormasse zeigt, dass ein mehr als 105-facher Überschuss an verfügbarem Phosphor bei Solldosierung des Reinigerkonzentrates vorhanden ist. Ein nur geringfügiges Ausmaß der o.g. Redoxreaktion dürfte demnach ausreichen, um relevante PH3-Konzentrationen im Bereich des MAK-Wertes im Spülraum zu erreichen. flächenbezogene Massenverlustrate [g°m-2°h-1] 1,0 0,8 0,6 0,4 0,2 0,0 0 2 4 6 8 10 12 pH-Wert Abbildung 1: Einfluss des pH-Wertes auf die flächenbezogene Massenverlustrate für die Aluminiumoxidschutzschicht (Daten aus [5]). Der eingetra- gene Punkt zeigt die überschlägig ermittelte Massenverlustrate im Reinigungsprozess bei den üblichen Betriebsbedingungen.
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