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 phenol production (RER): This dataset models the Hock process, which is the main process that is used for the production of phenol. In this process, cumene is transformed into phenol in two stages: (i) oxidation of the cumene, and (ii) cleavage into phenol and acetone. The oxidation happens in large reactors at a temperature of about 90-120°C and 0.5-0.7 MPa pressure. The whole reaction is autocatalytic and exothermic, releasing about 800 kJ per kilogram of cumene hydroperoxide to the environment by active cooling systems, mainly water. The second reaction – the cleavage – is an acid-catalyzed reaction, using almost exclusively sulphuric acid as catalyst. Two different ways are used within industry – called homogeneous phase (using 0.1-2% sulphuric acid) rsp. heterogeneous phase (40-45% sulphuric acid at a concentrate-acid ratio of 1:5). Also this second step is strongly exothermic – releasing ca. 1680 kJ per kilogram of cumene hydroperoxide cleaved. After the cleavage, further cleaning steps are used to achieve in the end a phenol purity of >99.9%. This includes neutralization and removing of sulphuric acid, followed by distillation processes. The overall yield of the production of phenol for this case here is assumed to be in the order of 95%. The inventory is based on stoechiometric calculations. The emissions to air (0.2 wt% of raw material input) and water were estimated using mass balance. Treatment of the wastewater in an internal wastewater treatment plant is assumed (elimination efficiency of 90% for C). 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 phenol production, from cumene (RER): This process consists first in the production of cumene from the reaction of benzene and propylene. Cumene then reacts with oxygen to give phenol and acetone. For each kilogram of phenol produced, 0.63 kg of acetone are obtained. For the process 0.6 MJ/kg of electricity and 9.1 MJ/kg of steam are required per kg of phenol and 0.2 MJ/kg of electricity and 9.8 MJ/kg of steam required per kg of acetone (Saygin 2009). Chemical reaction: C9H12 + O2 -> C6H6O + C3H6O 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 Gallardo Hipolito, M. 2011. Life Cycle Assessment of platform chemicals from fossil and lignocellulosic biomass scenarios LCA of phenolic compounds, solvent, soft and hard plastic precursors. Master in Industrial Ecology. Norwegian University of Science and Technology Department of Energy and Process Engineering. Retrieved from: http://daim.idi.ntnu.no/masteroppgaver/006/6362/tittelside.pdf, accessed 6 January 2017 SRI consulting. In: Gallardo Hipolito, M. 2011. Life Cycle Assessment of platform chemicals from fossil and lignocellulosic biomass scenarios LCA of phenolic compounds, solvent, soft and hard plastic precursors. Master in Industrial Ecology. Norwegian University of Science and Technology Department of Energy and Process Engineering. Retrieved from: http://daim.idi.ntnu.no/masteroppgaver/006/6362/tittelside.pdf, accessed 6 January 2017 Gallardo Hipolito, M. 2011. Life Cycle Assessment of platform chemicals from fossil and lignocellulosic biomass scenarios LCA of phenolic compounds, solvent, soft and hard plastic precursors. Master in Industrial Ecology. Norwegian University of Science and Technology Department of Energy and Process Engineering. Retrieved from: http://e-archivo.uc3m.es/bitstream/handle/10016/14718/Life%20Cycle%20Assessment%20of%20platform%20chemicals%20from%20fossil%20and%20lignocelulose%20scenarios.%20Martin%20Gallardo.pdf?sequence=2, accessed 6 January 2017 Saygin, D. 2009. Chemical and Petrochemical Sector Potential of best practice technology and other measures for improving energy efficiency. IEA information paper. IEA/OECD. Retrieved from: https://www.iea.org/publications/freepublications/publication/chemical_petrochemical_sector.pdf, accessed 6 January 2017 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)
technologyComment of carbon black production (GLO): The most important production process used nowadays is the oil-furnace process – other processes like e.g. thermal or acetylene carbon black processes are only of minor interests and therefore not further examined within this study here. The oil-furnace process is, according to Voll and Kleinschmit (2010) and Dannenberg and Paquin (2000) a partial combustion process of liquid aromatic residual hydrocarbons. The principle is to atomize the feedstock into the reactor, where it is decomposed into carbon black and hydrogen due to the fact that the oxygen available is not sufficient for a combustion of all the input. The reactor temperature is in the order of 1200 to 1900 °C, achieved through the combustion of natural gas and of the unreacted feedstock. After the decomposition, a fast quenching has to be done to avoid the loss by reaction of carbon black with carbon dioxide and water. The further processing consists mainly of drying and separation from other substances like tail gases, through a filter system. This dataset describes the production of carbon black with the oil-furnace process, using natural gas as further energy input. The inventory is based on literature information about two different types of carbon black, as well as estimations based on industrial data. The emission amount is estimated while the composition is based on literature. References: Voll, M. and Kleinschmit, P. 2010. Carbon, 6. Carbon Black. Ullmann's Encyclopedia of Industrial Chemistry. Dannenberg E. M. and Paquin L. (2000) Carbon Black. In: Kirk-Othmer Encyclopedia of Chemical Technology, Fourth Edition, Electronic Release, 4 th Electronic Release Edition. Wiley InterScience, New York, Online-Version under: http://www.mrw.interscience.wiley.com/kirk.
technologyComment of air separation, cryogenic (RER): The main components of air are nitrogen and oxygen, but it also contains smaller amounts of water vapour, argon, carbon dioxide and very small amounts of other gases (e.g. noble gases). The purification and liquefaction of various components of air, in particular oxygen, nitrogen and argon, is an important industrial process, and it is called cryogenic air separation. Cryogenic distillation accounts for approximately 85% of nitrogen and over 95% of oxygen production. It is the preferred supply mode for high volume and high purity requirements (Praxair 2002). Cryogenic air separation is currently the most efficient and cost-effective technology for producing large quantities of oxygen, nitrogen, and argon as gaseous or liquid products (Smith & Klosek 2001). Besides the air needed as a resource the major input for the liquefying process is the electricity to compress the inlet air, which normally comprises 95% of the utility costs of a cryogenic air separation plant. In some plants the amount of processed air (in Nm3) can be up to 5 times larger than the derived liquid products (Cryogenmash 2001). In these plants, the waste gas stream is naturally also much larger (in order to obtain the mass balance). As output of the cryogenic air separation there are three products: liquid oxygen, liquid nitrogen and liquid crude argon. The assumed process includes no gaseous co-products. In reality gaseous products are also processed if there is a demand at the production site. The investigated cryogenic air separation process leads to liquid products in the following quality: - Liquid oxygen: min. 99.6 wt-% - Liquid nitrogen: min. 99.9995 wt-% - Liquid argon, crude: 96-98 wt-% An air pre-treatment section downstream of the air compression (0.7 MPa) and after cooling removes process contaminants, including water, carbon dioxide, and hydrocarbons. The air is then cooled to cryogenic temperatures and distilled into oxygen, nitrogen, and, optionally, argon streams. Alternate compressing and expanding the recycled air can liquefy most of it. Numerous configurations of heat exchange and distillation equipment can separate air into the required product streams. These process alternatives are selected based on the purity and number of product streams, required trade-offs between capital costs and power consumption, and the degree of integration between the air separate unit and other facility units. This process requires very complicated heat integration techniques because the only heat sink for cooling or condensation is another cryogenic stream in the process. Since the boiling point of argon is between that of oxygen and nitrogen, it acts as an impurity in the product streams. If argon were collected and separated from the oxygen product, an oxygen purity of less than 95% by volume would result (Barron & Randall 1985). On the other hand, if argon were collected with the nitrogen product, the purity of nitrogen would not exceed 98.7% by volume. To achieve higher purities of oxygen and nitrogen the elimination of argon is necessary. Commercial argon is the product of cryogenic air separation, where liquefaction and distillation processes are used to produce a low-purity crude argon product. Praxair (2002) Gases > Nitrogen > Production of Nitrogen. Praxair Technology Inc. 2002. Retrieved 16.01.2002 from http://www.praxair.com Smith A. R. and Klosek J. (2001) A Review of Air Separation Technologies and their Integration with Energy Conversion Processes. In: Fuel Processing Technology, 70(2), pp. 115-134. Barron and Randall F. (1985) Cryogenic Systems. 2 Edition. Oxford University Press, New York Cryogenmash (2001) KxAxApx Type Double-Pressure Air Separation Plants. Gen-eral Data. Cryogenic Industries, Moscow, Russia. Retrieved 16.01.2002 from http://www.cryogenmash.ru/production/vru/vru_kgag2_e.htm imageUrlTagReplaceb1f86554-243f-4c79-b3a2-e6a9efa3a7ef
technologyComment of acetylene production (RER): Partial oxidation of natural gas. The flue gas is assumed to be cleaned with electrofilters. References: Pässler, P., Hefner, W., Buckl, K., Meinass, H., Meiswinkel, A., Wernicke, H.-J., Ebersberg, G., Müller, R., Bässler, J., Behringer, H. and Mayer, D. 2011. Acetylene. Ullmann's Encyclopedia of Industrial Chemistry. 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 natural gas liquids fractionation (GLO): The recovered NGL stream is processed through a fractionation train consisting of up to five distillation towers in series: a demethanizer, a deethanizer, a depropanizer, a debutanizer and a butane splitter. The overhead product from the deethanizer is ethane and the bottom product is fed to the depropanizer. The overhead product from the depropanizer is propane and the bottom is fed to the debutanizer. The overhead product from the debutanizer is a mixture of normal and iso-butane, and the bottom is a C5+ gasoline mixture (pentane in this inventory). A slightly simplyfied fractioning process can be seen in the sketch below. imageUrlTagReplace937d93d2-cfed-4ec9-9363-614415661a5c Source: Thompson S. M., Robertson G. (2011): Liquefied Petroleum Gas, in Ullmanns Encyclopedia of Industrial Chemistry, 7th Edition. technologyComment of natural gas production (CA-AB): Canadian data completed with german data. The uncertainty has been adjusted accordingly. Data used in original data contains no information on technology. technologyComment of natural gas production (RoW): The data describes an average onshore technology for natural gas to 13% out of combined oil gas production. Natural gas is assumed to 20% sour. Leakage in exploitation is estimated at 0.38% and production 0.12%. It is further assumed that about 30% of the produced water is discharged in surface water. Water emissions are differentiated between combined oil and gas production and gas production.
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 natural gas liquids fractionation (GLO): The recovered NGL stream is processed through a fractionation train consisting of up to five distillation towers in series: a demethanizer, a deethanizer, a depropanizer, a debutanizer and a butane splitter. The overhead product from the deethanizer is ethane and the bottom product is fed to the depropanizer. The overhead product from the depropanizer is propane and the bottom is fed to the debutanizer. The overhead product from the debutanizer is a mixture of normal and iso-butane, and the bottom is a C5+ gasoline mixture (pentane in this inventory). A slightly simplyfied fractioning process can be seen in the sketch below. imageUrlTagReplace937d93d2-cfed-4ec9-9363-614415661a5c Source: Thompson S. M., Robertson G. (2011): Liquefied Petroleum Gas, in Ullmanns Encyclopedia of Industrial Chemistry, 7th Edition. technologyComment of natural gas production (CA-AB): Canadian data completed with german data. The uncertainty has been adjusted accordingly. Data used in original data contains no information on technology. technologyComment of natural gas production (RoW): The data describes an average onshore technology for natural gas to 13% out of combined oil gas production. Natural gas is assumed to 20% sour. Leakage in exploitation is estimated at 0.38% and production 0.12%. It is further assumed that about 30% of the produced water is discharged in surface water. Water emissions are differentiated between combined oil and gas production and gas production.
technologyComment of methanol production (GLO): For normal methanol synthesis, reforming is performed in one step in a tubular reactor at 850 – 900 °C in order to leave as little methane as possible in the synthesis gas. For large methanol synthesis plants, Lurgi has introduced a two-step combination (combined reforming process) that gives better results. In the primary tubular reformer, lower temperature (ca. 800 °C) but higher pressure (2.5-4.0 MPa instead of 1.5-2.5 MPa) are applied. More recently, Lurgi developed another two-step gas production scheme. It is based on catalytic autothermal reforming with an adiabatic performer and has economical advantages for very large methanol plants. At locations where no carbon dioxide is available most of the methanol plants are based on the following gas production technologies, depending on their capacities: steam reforming for capacities up to 2000 t d-1 or combined reforming from 1800 to 2500 t d-1 (Ullmann 2001). For the energy and resource flows in this inventory a modern steam reforming process was taken as average technology. To estimate best and worst case values, also values from combined reforming and autothermal reforming were investigated. Methanol produced using a low pressure steam reforming process (ICI LPM) accounts for approximately 60% of the world capacity (Synetix 2000a). Besides steam reforming, combined reforming has gained importance due to the production of methanol in large plants at remote locations. The reaction of the steam-reforming route can be formulated for methane, the major constituent of natural gas, as follows: Synthesis gas preparation: CH4 + H2O → CO + 3 H2; ΔH = 206 kJ mol-1 CO + H2O → CO2 + H2; ΔH = - 41 kJ mol-1 Methanol synthesis: CO + 2 H2 → CH3OH; ΔH = -98 kJ mol-1 CO2 + 3 H2 → CH3OH + H2O; ΔH = -58 kJ mol-1 For an average plant the total carbon efficiency is around 75%, 81% for the synthesis gas preparation and 93% for the methanol synthesis (Le Blanc et al. 1994, p. 114). For steam reformers usually a steam to carbon ratio of 3:1 to 3.5:1 is used. As methanol production is a highly integrated process with a complicated steam system, heat recovery and often also internal electricity production (out of excess steam), there were only data of the efficiency and energy consumption of the total process available. Therefore the process was not divided into a reforming process, a synthesis process and a purification process for estimating the energy and resource flows. Also the energy and resource flows in the methanol production plants are site specific (dependent on the local availability of resources such as CO2, O2, or electricity). In this inventory typical values for a methanol plant using steam-reforming technology were used. The main resource for methanol production is natural gas, which acts as feedstock and fuel. A natural gas based methanol plant consumes typically 29-37 MJ (LHV) of natural gas per kg of methanol. This gas is needed as feedstock for the produced methanol (20 MJ kg-1 LHV) and also used as fuel for the utilities of the plant. From the converted feed, 1 kg methanol and 0.06 kg hydrogen is yielded. It was assumed that the purged hydrogen was also burned in the furnace. The only emission to air considered from burning hydrogen is NOX. The energy amount generated is not considered, because the process of the furnace is specified for natural gas as fuel. The NOX emissions of the hydrogen burning were therefore calculated separately. 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 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 dimethyl carbonate production (RER): Dimethyl carbonate has been historically produced through the reaction of phosgene and methanol. Because of the toxicity of phosgene, a greener route of production has been developed (Tundo and Selva 2002). Today it is mostly produced through the reaction of ethylene or propylene carbonate with methanol. This activity models the production of dimethyl carbonate as the result of the reaction of ethylene carbonate and methanol. Chemical reaction: C3H4O3 + CH3OH -> C3H6O3 + CH2O 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 Tundo, P. and Selva, M. 2002. The Chemistry of Dimethyl Carbonate. Acc. Chem. Res. Vol.9, 35, pp. 706–716 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) technologyComment of oxidation of methanol (RER): Represents a current cross-section of actual plants in Europe. The inventory is based on 100% formaldehyde production. The inputs and outputs are an average of the Silver and Formox processes. Silver process: Initially, methanol is dehydrogenated and subsequently there is combustion of hydrogen overall resulting in the production of formaldehyde and water. The raction takes place with air over a crystalline silver catalyst. Formox process: Methanol is directly oxidized by air over a metal oxide catalyst at a temperature of 470 °C. excess heat is removed with an oil-transfer medium. The product gases are cooled, absorbed in water, and an aqueous 37% formaldehyde solution is obtained. (Wells, 1999) References: G. Margaret Wells, “Handbook of Petrochemicals and Processes”, 2nd edition, Ashgate, 1999 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.