10716cd4-7418-44a8-81a7-844104f85901Ingeo Polylactide (PLA) biopolymer productionNatureWorks LLC processproduction mix, at plantPLAProcessesIndustry dataNatureWorksThe LCI data is only representative for Ingeo produced by NatureWorks in Blair Nebraska and not for PLA production in general.
The life cycle inventory data for PLA produced elsewhere will be different due to different raw materials (sugar or starch source) and raw material production practices, different technologies for processing these raw materials, different fermentation and polymerisation technology and different background data for electricity/fuel mixes used.
For these reasons, the specific nomenclature "Ingeo" is used in this data module to clearly delineate wherever NatureWorks polylactide biopolymer is being referenced.
The data source for the NatureWorks LLC specific manufactoring processes is NatureWorks LLC. The information represents the current state of the art at the NatureWorks LLC plant in Blair, Nebraska. All background data are taken from the GaBi data base.94Primary manufacturing information represents the NatureWorks LLC specific manufacturing technology.
Fuels and energy input in the system represent US specific situation.The flow diagram for the manufacture of virgin Ingeo resin is shown below (see Flow diagram for the manufacture of Ingeo polylactide biopolymers)
The cradle-to-factory-gate Ingeo production system is divided into five major steps:
1. Corn production and transport of corn to the corn processing wet mill;
2. Corn processing and the conversion of starch into dextrose;
3. Conversion of dextrose into lactic acid;
4. Conversion of lactic acid into lactide; and
5. Polymerization of lactide into polylactide polymer pellets.
CORN PRODUCTION
The life cycle of Ingeo starts with corn (maize) production. All free energy consumed by the corn plant comes from solar energy captured by the photosynthesis process. The basic stoichiometric equation for photosynthesis is:
light
H2O + CO2 -----> (CH2O) + O2
In this equation, (CH2O) represents carbohydrate, such as sucrose and starch. Therefore all carbon, hydrogen and oxygen found in the starch molecule or the final polylactide molecule originated from water and carbon dioxide.
The data includes all the relevant inputs for corn production such as production of corn seed, fertilizers, lime stone, electricity and fuels (natural gas, diesel, propane and gasoline) used on the farm, the atmospheric carbon dioxide utilization through photosynthesis, the irrigation water applied to the corn field and the production of the herbicides and insecticides used to grow the corn. On the output side, emissions including dinitrogen oxide, nitrogen oxides, nitrates and phosphates are taken into account. Production of the farm equipment (tractors and harvest combines) used was investigated, but their contributions are negligible.
The average life cycle data on corn production was collected from corn producers in the twenty-six counties in Nebraska and Iowa that tend to supply corn to the corn wet mill that processes corn into dextrose syrup. These counties are situated on the borderline of Nebraska and Iowa.
The ultimate #cradle# in the life cycle of corn is seed production. Although attempts to fully account for the impacts of seed corn production could lead to an endless recursive accounting of ever more diminutive impacts, never quite reaching zero, the LCI reasonably accounts for the energy production associated with seed corn production. The average seed consumption is estimated at 0.00193 kg/kg corn. [2]
DEXTROSE PRODUCTION
Data for a modern corn wet mill representative of the Cargill corn wet mill that supplies the dextrose solution was compiled and used for the dextrose production step.
After harvest, the corn grain is transported to a corn wet mill (CWM), where the starch is separated from the other components of the corn kernel (proteins, fats, fibers, ash and water) and hydrolyzed to dextrose using enzymes. The unrefined dextrose solution is transported by pipeline to the fermentation process, which is situated adjacent to the CWM. The other products of the modeled CWM are corn gluten feed, corn gluten meal, heavy steep water and corn germ. The data includes all relevant inputs for dextrose production such as the production and delivery of natural gas, electricity and steam consumed, as well as the production of potable and cooling water, compressed air, chemicals (sulfur dioxide and calcium hydroxide) and enzymes.
LACTIC ACID PRODUCTION
Lactic acid is produced by fermentation of dextrose received from the CWM. The process, illustrated below in "NatureWorks LLC lactic acid production process", combines dextrose and other media, adds a microbial inoculum and produces crude lactic acid. Till December 2008 the pH was controlled by the addition of calcium hydroxide. The lactic acid broth was then acidified by adding sulfuric acid, resulting in the formation and precipitation of gypsum. The gypsum was removed by filtration and the lactic acid was concentrated by evaporation. In December 2008 new fermentation technology was introduced significanlty reducing the use of calcium hydroxide and sulfuric acid resulting in significantly lower quantities of gypsum. Also less energy was required to drive the process. Still small quantities of gypsum are being produced which are finally used in land application and so replacing mined gypsum. A credit is given for the avoided gypsum mining, but the impact of that is small compared to the total numbers. After final purification, the lactic acid enters the lactide/Ingeo manufacturing process.
LACTIDE AND POLYMER PRODUCTION
Ingeo is prepared through the polymerization of lactide to make polylactide polymer. The process, illustrated below in "NatureWorks LLC lactide formation and polylactide polymerization process", is a continuous process. In the first step, water is removed in a continuous condensation reaction of aqueous lactic acid to produce low molecular weight prepolymer. Next, the prepolymer is catalytically converted into the cyclic dimer, lactide. The molten lactide mixture is then purified by distillation. Finally, high-molecular-weight Ingeo is produced using a ring-opening lactide polymerization. The process does not use solvents. After the polymerization is complete, any remaining lactide monomer is removed and recycled within the process [4,5,6]. The polymer pellets are the final stage of the Ingeo eco-profiles. Packaging and transportation to the customer are not included.
STEAM PRODUCTION
Steam is being produced in a natural gas fired steam boiler located at the Cargill site.
A part of the steam produced is used in the process, a part is lost by evaporation and a part recycled as condensate to the steam boiler. Make up potalbe water is included in the inventory and well as electricity use by the steam boiler.
WATER CONSUMPTION
The inventory distinguish three types of water: irrigation water used for corn production, process water used as a transportation medium, reaction medium and for steam production and make up water for cooling tower losses.
GYPSUM MINING
See the lactic acid production process.
THERMAL OXIDIZER
The Ingeo production process is equipped with two thermal oxidizers converting organic process emissions into carbon dioxide and water. Also the natural gas consumption of the thermal oxidizers is taken into account.
WASTE WATER TREATMENT
Dextrose and lactic acid manufacturing are water based processes. A part of the water is recycled internally and a part is drained, after processing in a waste water treatment facility, on the surface water (river). Electricity consumption and the process emissions (to air and water) of the on-site facility are included in the inventory.
SOLID WASTE GENERATED
1. Mineral waste: Mineral waste refers to waste earth and rock generated in mining operations. The principal source of mineral waste is in coal production. Frequently, mineral waste is returned to a mine working once the valuable minerals have been removed and so represents a measure of the rock moved rather than the generation of permanent waste. Where the waste is known to be returned to the mine, it is recorded separately as waste returned to mine.
The energy required "to move the rock" is already included in the LCI.
2. Slags & ash: Slags and ash refer to the solid waste produced by industrial boilers and furnaces. This is usually inert and because it contains no organic matter that can decay with time, it is frequently used in civil engineering operations such as road building. When slags and ashes are used in civil engineering projects they are products from the process producing them and so carry with them a proportion of the burdens of the processes.
3. Mixed industrial waste: Mixed industrial waste is a catch-all classification so that if the waste does not fit into any of the other categories it will normally appear here. Usually this consists of wastes such as discarded industrial packaging and general housekeeping waste and is similar to domestic refuse that would usually be handled by municipal authorities.
4. Regulated chemicals waste: Waste from chemical processes has been divided into two categories referred to as inert chemical waste and regulated chemical waste. The terminology is imperfect because there is strictly no such thing as unregulated waste. However, the essential physical distinction between these two categories is that inert chemical waste could, in principle, be sent to landfill sites without further treatment whereas regulated chemical waste represents the category of chemical waste that has to be sent to special storage sites because it is corrosive or toxic. In practice, the distinction is often determined less by the physical characteristics of the waste as by the prevailing local regulations. For example, landfilling chemical waste of any type is forbidden in some countries and locations but allowed in others.
5 Unregulated chemicals waste. Description is given at 4.
6. Waste returned to mine. Description is given at 1.
7. Tailings waste: A further category of mine waste is mine tailings. This represents the residue left after mineral processing and may be inert or contain processing chemicals. In remote mines, tailings will usually be disposed of locally.
The background system is addressed as follows: The electricity used is modelled according to the individual country-specific situation. The country-specific modelling is achieved on multiple levels. Firstly the individual power plants in service are modelled according to the current national grid. This includes net losses and imported electricity. Second, the national emission and efficiency standards of the power plants are modelled. Third, the country-specific fuel supply (share of resources used, by import and / or domestic supply) including the country-specific properties (e.g. element and energy contents) are accounted for. Fourth, the import, transport, mining and exploration processes for the energy carrier supply chain are modelled according to the specific situation of each power-producing country. The different mining and exploration techniques (emissions and efficiencies) in the different exploration countries are accounted for according to current engineering knowledge and information. Furthermore all relevant and known pipeline and / or tanker transport of gases and oil imports are included. Energy carriers: Coal, crude oil, natural gas and uranium are modelled according to the specific import situation (see electricity). Refinery products: Diesel, gasoline, technical gases, fuel oils, basic oils and residues such as bitumen are modelled via a country-specific, refinery parameterized model. The refinery model represents the current national standard in refinery techniques (e.g. emission level, internal energy consumption,...) as well as the individual country-specific product output spectrum, which can be quite different from country to country. Hence the refinery products used show the individual country-specific use of resources. The supply of crude oil is modelled, again, according to the country-specific crude oil situation with the respective properties of the resources.Natural gas mixDiesel mix at refineryThermal energy from natural gas (eGrid)Gasoline mix (regular) at refineryElectricity grid mix (East)Ingeo polymer can be used to substitute a crude oil based polymer.NatureWorks LLC Flow diagram for the manufacture of Ingeo polylactide biopolymers.jpgNatureWorks LLC lactic acid production process.jpgNatureWorks LLC lactide formation and polylactide polymerization process.jpgLCI resultAttributionalNoneAllocation - market valueAllocation - net calorific valueAllocation - exergetic contentAllocation - massFor details please see "GaBi Database modelling principles".Transportation is modelled using average transportation processes.NoneCut-off rules:
Coverage at least 95% of mass and energy (input as well as output flows) and 98% of their environmental relevance.
For more detail, please see "GaBi modelling principles".NoneFor more detail, please see "GaBi modelling principles".NoneFor more detail, please see "GaBi modelling principles".NoneGaBi databases100.0The LCI data is only representative for Ingeo produced by NatureWorks in Blair Nebraska and not for PLA production in general.
It should be used only to represent NatureWorks Ingeo.All relevant flows quantifiedThe LCI method applied is in compliance with ISO 14040 and 14044. The documentation includes all relevant information in view of the data quality and scope of the application of the respective LCI result / data set. The dataset represents the state-of-the-art in view of the referenced functional unit.PE INTERNATIONALLBP-GaBiIBP-GaBiNatureWorks LLCThe LCI data is only representative for Ingeo produced by NatureWorks in Blair Nebraska and not for PLA production in general.
It should be used only to represent NatureWorks Ingeo.PE INTERNATIONALNatureWorks LLC2014-12-01T00:00:00+01:00ILCD format 1.1PE INTERNATIONAL2014-12-01T00:00:00+01:0009.00.000Data set finalised; entirely publishedGaBi databasesNatureWorks LLCtrueOtherGaBi (source code, database including extension modules and single data sets, documentation) remains property of PE INTERNATIONAL AG. PE INTERNATIONAL AG delivers GaBi licenses comprising data storage medium and manual as ordered by the customer. The license guarantees the right of use for one installation of GaBi. Further installations using the same license are not permitted. Additional licenses are only valid if the licensee holds at least one main license. Licenses are not transferable and must only be used within the licensee's organisation. Data sets may be copied for internal use. The number of copies is restricted to the number of licenses of the software system GaBi the licensee owns. The right of use is exclusively valid for the licensee. All rights reserved.Ingeo Polylactide (PLA) biopolymer (by NatureWorks LLC)Output110.000Mixed primary / secondaryMeasured