We helped B’ZEOS compare the environmental impact of their seaweed packaging solution by analyzing the cradle to grave impact of their product and compare it with other biobased and fossil fuel based solutions on the market. Project completed October 2024.B'ZEOS wanted to know how their product design performed against their competitors and know more about how the choice of input materials affected the overall environmental impact of their product.
The study constituted a prospective LCA of a packaging solution currently under development by the company, produced from seaweed extracts. This was then compared, on a cradle-to-grave basis, to equivalent products based on other petrochemical and bio-based materials available on the market. The results allowed B’ZEOS to not only benchmark the environmental performance of their product against potential competitors, but also to gain insights as to how to improve this performance regarding aspects such as product design, choice of raw materials and implications in terms of product disposal at the end of its useful life.
Purpose
Ethylene and propylene production is currently included in life cycle assessment (LCA) databases using an attributional life cycle inventory (LCI) modelling approach. This approach entails modelling both products as co-products of the steam cracking process. In this article, we provide what, to the best of our knowledge, constitutes the first attempt to construct a consequential LCI model for ethylene and propylene production, focusing on European conditions and using publicly available data.
Methods
A market analysis for the European market was conducted, showing that steam cracking of naphtha is the marginal production route for ethylene, while for propylene the marginal production route is propane dehydrogenation (PDH). This market analysis also identifies propane as a constrained feedstock and suggests that an increase in demand for propane will induce a shift to gasoline consumption by ‘autogas’ vehicles. Following these findings, we develop a consequential LCI model including PDH, steam cracking, treatment of steam cracking by-products (butadiene extraction, pyrolysis gasoline hydrotreatment, benzene-toluene-xylenes extraction), and marginal production routes for all substituted products, such as hydrogen, butadiene, benzene, toluene, and mixed xylenes, among others. The LCI model was linked to the background ecoinvent database.
Results and discussion
The model was evaluated at the impact assessment level, focusing only on greenhouse-gas (GHG) emissions per kg product, showing that they are larger for ethylene (1.83 kg CO2e) compared to propylene (1.35 kg CO2e). In both cases, the main contribution is the supply of feedstock, namely naphtha and propane, respectively, although total emissions are highly influenced by substitutions associated with by-products. For ethylene, several substituted products occur, especially benzene, hydrogen, and propylene, while for propylene the only relevant substitution is for hydrogen. A sensitivity analysis shows that the results for both propylene and ethylene are highly sensitive to how the propane constraint is addressed. In particular, GHG emissions for propylene drop by 48% and those for ethylene increase by 22% when the marginal propane user shifts to natural gas instead of gasoline.
Conclusions
A consequential approach shows that a demand for ethylene and propylene, respectively, triggers and affects different production processes, thereby yielding distinct cradle-to-gate environmental impacts for each product. This stands in contrast to typical attributional models employing mass allocation (partitioning), which results in identical impacts per kilogram. Future research efforts should be aimed at validating the presented model, as well as expanding it to cover regions other than Europe, where marginal propylene production routes may vary.
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The study compared the life cycle environmental impact of alternative options for a control panel incorporated in a coffee maker, designed with:
In the study, the control panels were tracked from ‘cradle to grave’, including the following life cycle stages: Supply of components and packaging, manufacturing of the control panel, distribution, use and disposal of control panel and packaging.
The Impact Assessment aggregates the information from the Inventory Analysis into a set of 14 indicators addressing the use of natural resources and impacts on human health and ecosystems, for example, health effects from particulate pollution or nature occupation.
The IMSE and IMSE SiP control panels involve a lower life cycle environmental impact than the reference control panel. The reduction in impact varies depending on the indicator. For example, greenhouse gas (GHG) emissions (the carbon footprint) are reduced by 56% and 62% by IMSE and IMSE SiP, respectively, compared to the reference.
In all indicators, the IMSE SiP option leads to a lower life cycle impact than the IMSE option. As an example, GHG emissions are 14% lower in the IMSE SiP option as compared to the IMSE option.
Most of the environmental damage induced by the control panel life cycle is associated with the indicator for respiratory inorganics (emissions of particulate pollution), closely followed by global warming (emissions of GHG).
For all three control panels, the supply of components dominates the life cycle impact, with all other stages representing a relatively low fraction of the total impact. For IMSE and IMSE SiP, the supply of components represents 85% and 84%, respectively, of the life cycle GHG emissions. Among components, the supply chain of electronics (touch film, FPC, PCB, controller, transistor, connector, LED) constitutes the main contribution to life cycle impacts.
More information can be found in the presentation given by Ivan Muñoz in the webinar hosted by TactoTek on 23rd February 2022: “Environmental Performance of IMSE”. A critical review is mentioned in a further insights blog post.
The study has been commissioned by DuPont Transportation & Industrial Business and conducted by 2-0 LCA. An external third-party critical review according to ISO/TS 14071:2014 was conducted by a three-member independent review panel.
Environmental life cycle data on materials, transport and energy from many different sources are available in the Plastics Calculator. The user (typically from the plastic industry) only has to supplement with foreground data from their own production line.
The result from a calculation is a complete overview of the products environmental profile in the form of an environmental product declaration (printable in pdf-format). This can be used for communication purposes as well as for environmental optimisation of the production.
NaOH (sodium hydroxide or caustic soda) is a by-product of the chlorine-alkali process. As this process is determined by the long-term demand for chlorine, changes in demand for NaOH does not affect the output of NaOH from this process.
An analysis of the NaOH market reveals that long-term changes in demand for NaOH will affect the least essential uses of NaOH, i.e. those uses where NaOH can readily displace sodium carbonate (soda ash). A long-term increase in demand for NaOH will thus be met by an increased use of sodium carbonate for those uses where NaOH is not essential, e.g. in pulp and paper, water treatment, and certain chemical sectors where it is used as a neutralising agent. Likewise, a long-term decrease in demand for NaOH will lead to increased displacement of sodium carbonate.
In the current market situation, where there is a global increase in demand for chlorine, the continuously increasing output of NaOH is adequate to cover the applications where NaOH is essential, and a marginal increase in NaOH demand will therefore not lead to a need to produce NaOH from the alternative process route (the caustification process, where NaOH is produced from lime and soda). If there is a further increase in demand for NaOH for essential applications, without a simultaneous increase in demand for chlorine, the caustification process will again be able to play a role as a marginal production route for NaOH, as has been the case previously.
To model the current long-term market reaction to a decreased demand for NaOH in a life cycle assessment, we thus recommend using the derived decrease in sodium carbonate supply. Sodium carbonate is currently produced from NaCl and CaCO3 in the Solvay process (in Europe), and in addition directly from naturally occurring ores (trona) or brines (USA). The displaced sodium carbonate supply may therefore depend on the location and transport costs. The Solvay process is still the dominating process globally, implying that the output from the naturally occurring sources are not globally competitive, and that a decrease in NaOH demand will primarily affect the Solvay process. Sources for environmental data for the Solvay and the trona mining processes are identified.
