11 Search Results

Advanced recycling enables the application of post-use plastics (PUP) to produce valuable industrial chemicals and develop markets for recycled feedstocks. Pyrolysis is one of the most common advanced recycling technologies undergoing industrial-scale implementation for converting PUP. This paper presents a life cycle analysis (LCA) to assess greenhouse gas (GHG) emissions, fossil energy, water consumption, and solid waste impacts of converting PUP into new plastics such as high-density and low-density polyethylene (HDPE and LDPE, respectively). Data was collected from eight plastic pyrolysis companies. This study addresses the impacts of pyrolysis plant size and maturity; two substitution rate (SR) cases of pyrolysis oil with fossil-derived feedstocks in steam crackers (5% and a 20% of pyrolysis oil SR); and potentially avoided emissions from traditional end-of-life (EOL) management. Because the conventional feedstock slate of steam crackers in the Unites States is comprised of 94% gases (a mix of ethane, propane, and butane) and 6% naphtha, the 5% SR case looked at polyethylene (PE) derived from 5% pyrolysis oil, 1% naphtha, and 94% gases; while the 20% SR looked at PE derived from 20% pyrolysis oil and 80% gases. Moreover, the results are presented from two perspectives: 1) steam crackers' and 2) plastic recyclers'. In the recyclers' perspective, the results for the 5% SR showed for each kg of PUP used there was a 23% and 18% decrease in GHG emissions for HDPE and LDPE respectively, while the 20% SR showed a 4% and 3% reduction in GHG emissions for HDPE and LDPE respectively compared to virgin plastic. The 20% SR has lower GHG emissions reductions because there is an added step of hydrotreating the pyrolysis oil to remove chlorine concentrations that is not included in the 5% SR scenario. Furthermore, the 5% SR removes most of the naphtha, a more carbon intense feedstock, and replaces it with PUP-based pyrolysis oil, a less carbon intense feedstock. GHG emissions for PUP pyrolysis could be further reduced by 50% and 131% in the United States and European Union respectively if the GHG emissions of current PUP incineration practices were considered as emission reductions credits.

The urgent need for greenhouse gas (GHG) emission reductions to mitigate climate change calls for accelerated biorefinery development and biochemical deployment to the market as structural or functional replacements for chemicals produced from fossil-derived feedstocks. This study evaluated the energy and environmental impacts of 15 biochemicals with clear near-term market potential and their fossil-based counterparts, when applicable, on a cradle-to-gate basis. Three of these chemicals are produced exclusively from biomass; eight are predominantly produced from fossil-derived feedstocks; and four are predominantly produced from biomass. For the 12 cases that can be produced from either feedstock, eight exhibited fossil energy consumption and GHG emission reductions when produced from biomass instead of fossil-derived feedstocks between 41%–85% and 35%–350%, respectively. Water consumption results were mixed because several of the biobased pathways consumed more water. Annually, replacing the predominantly fossil-fuel-based chemicals with biobased alternatives could avoid 120 MMT CO2e emissions and save 1,500 PJ of fossil energy. The potential of these chemicals as coproducts in integrated biorefineries was analyzed in terms of market, economics, and environmental effects with an emphasis on GHG emissions. Adipic acid, succinic acid, acrylic acid, propylene glycol, 1,4-butanediol, 1,3-butadiene, furfural, and fatty alcohol are promising coproduct candidates based on their low life-cycle GHG emissions.

The establishment of the circular economy (CE) for plastics aims to reduce material losses and dependence on virgin materials; however, this practice does not necessarily imply reduction of life-cycle impacts. In this study, a CE sustainability analysis framework combining life-cycle assessment (LCA) and material flow analysis (MFA) was developed to simultaneously evaluate the life-cycle impacts and circularity metrics of implementing different CE strategies of production of plastic packaging, using poly(ethylene terephthalate) (PET) bottles as an example. The strategies included increasing the recycling rate of PET bottles and integrating two chemical recycling technologies in industrial development: enzymatic hydrolysis and methanolysis. The energy use of enzymatic hydrolysis and methanolysis was estimated to be 57 and 38 MJ/kg PET, respectively, while the two technologies accounted for greenhouse gas (GHG) emissions of 3.0 and 2.0 kg CO₂ e/kg PET, respectively. The analysis at the system level demonstrated that compared to the current practice, relying on 97% virgin PET resin, the joint implementation of these strategies generated similar GHG emissions (3.2 kg CO₂ e/kg bottle) but reduced virgin material use and solid waste generation by 56 and 64%, respectively. Based on present technology development, increasing the share of mechanically recycled resin in bottle manufacturing and using a decarbonized electricity grid resulted in 14 and 9% lower GHG emissions, respectively, than the current supply chain.

In this report, we present an updated LCA of the PTF pathway developed at Argonne. Benavides et al. (2017) analyzed the environmental impact of producing ultra-low sulfur (ULS) diesel fuel from PUP via pyrolysis (the most common PTF technology). We used the Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET®) model and collected data from eight PTF companies to assess the potential energy and environmental benefits associated with this technology (Argonne, 2020). We conducted a survey and aggregated the dataset based on the different responses, which included plant capacity, process yields, feedstock composition, material and energy inputs, and outputs, and other parameters. We calculated the energy, greenhouse gas (GHG) emissions, and water consumption of its intermediate product pyrolysis oil and final product PUP-derived ULS diesel and compared the results to those metrics for their conventional counterparts (crude naphtha and petroleum ULS diesel fuel).

The Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET®) model was developed by Argonne National Laboratory (Argonne) with the support of the U.S. Department of Energy (DOE) and other federal agencies. R&D GREET is a life cycle analysis (LCA) model, structured to systematically examine the energy and environmental effects of a wide variety of transportation fuels and vehicle technologies in major transportation sectors (i.e., road, air, marine, and rail), other end-use sectors, and energy systems. Argonne has expanded and updated the model in various areas in R&D GREET 2023. This report provides a summary of the expansions and updates.

Polyethylene furanoate (PEF) is a bioplastic that can potentially replace its fossil-fuel counterpart, polyethylene terephthalate (PET), to reduce greenhouse gas (GHG) emissions. A life-cycle GHG, water, and fossil-fuel consumption analysis is conducted for a potential bioplastic alternative for a fossil-based PET resin, or PEF on a kg-resin basis. PEF is assumed to be produced from a lignocellulosic feedstock (i.e., wheat straw) via furanics conversion reactions through three different pathways. The system boundary includes cradle-to-gate processes including feedstock farming, pretreatment, hydrolysis, conversion into furanics, recovery, polymerization into PEF, and on-site combined heat and power (CHP) generation. While electricity export from the CHP plant is assumed to displace the U. S. grid electricity, other coproducts of PEF are assumed to distribute the emissions and energy burdens on a mass basis. The results showed that all three PEF routes achieved significant GHG reduction relative to its fossil-based counterpart (i.e., PET): 134, 139, and 163% reduction for routes 1, 2, and 3, respectively. While fossil-fuel consumptions for all three pathways were also significantly reduced (i.e., 79, 57, and 53% reduction for routes 1, 2, and 3), water consumptions for routes 1 and 2 were increased by 168 and 79%, respectively, while route 3 only achieved reduction (by 77%) relative to fossil-PET. Different sensitivity analyses were conducted, and the results showed that coproduct allocation methods and wheat straw management assumption were the most important. A preliminary analysis on the farmland area and cost required to reduce unit mass of GHGs using PEF to replace PET is also conducted, showing a promising result for both metrics: (i) 3 metric tons of GHGs reduced/ha for all three PEF pathways and (ii) affordable cost of GHG abatement for routes 1 and 2, while route 3 even generated profits.

Steam cracking is an energy-intensive process used to convert natural gas liquids, naphtha, and gas oil into ethylene and propylene, as well as other chemicals. It is the primary source of ethylene, one of the most important building blocks for the chemical and plastics industry. Steam cracking also co-produces hydrogen which is typically combusted with the tail gas onsite for process heat, but alternatively could be separated and sold as a by-product. This study provides a detailed life cycle inventory for the United States steam cracking industry based on publicly-available, facility-specific information; provides industry average results; and assesses variability across facilities, feedstocks, and technologies. This life cycle inventory provides the baseline needed for comparison of plastic alternatives designed to improve recyclability and reduce the environmental effects of plastics. Likewise, the environmental profile of by-product hydrogen from steam crackers is important for assessing its potential benefit in decarbonizing transportation and/or industry, considering the energy use for separation and compression, as well as the make-up fuel requirements. We present the cradle-to-gate results for all steam cracking products and find the life cycle GHG emissions for average U.S. ethylene and propylene are 1.13 kg CO₂e per kilogram using a mass allocation, 1.05 kg CO₂e for facilities that combust their hydrogen, and 1.30 kg CO₂e for facilities that separate by-product hydrogen for use. With natural gas production and ethylene demand continuing at high levels in the United States, decarbonizing steam cracking would be an important step toward mitigating emissions from the chemical industry. Similarly, the benefit of using by-product hydrogen to decarbonize other processes is dependent on the relative benefit of the hydrogen application compared with the alternative energy source used for steam cracking process heat. Results are also reported for criteria air pollutant emissions, energy use, water use, and a series of life cycle impact potentials.

Today, polyurethanes are effectively not recycled and are made principally from nonrenewable, fossil-fuel-derived resources. This study provides the first high-resolution material flow analysis of polyurethane flows through the U.S. economy, tracking back to fossil fuels and covering polyurethane-relevant raw materials, trade, production, manufacturing, uses, historical stocks, and waste management. According to our analysis, in 2016, 2900 thousand tonnes (kt) of polyurethane were produced in the United States and 920 kt were imported for consumption, 2000 kt entered the postconsumer waste streams, and 390 kt were recycled and returned to the market in the form of carpet underlayment. The domestic production of polyurethane consumed 1100 kt of crude oil and 1100 kt of natural gas. With the developed polyurethane flow map, we point out the limitation of the existing mechanical recycling methods and identify that glycolysis, a chemical recycling method, can be used to recycle the main components of postconsumer polyurethane waste. We also explore how targeting biobased pathways could influence the supply chain and downstream markets of polyurethane and reduce the consumption of fossil fuels and the exposure to toxic precursors in polyurethane production.

The GREET^® (Greenhouse gases, Regulated Emissions, and Energy use in Technologies) model has been developed by Argonne National Laboratory (Argonne) with the support of the U.S. Department of Energy (DOE) and other federal agencies. GREET is a life cycle analysis (LCA) tool, structured to systematically examine the energy and environmental effects of a wide variety of transportation fuels and vehicle technologies in major transportation sectors (i.e., road, air, marine, and rail) and other end-use sectors, and energy systems. Argonne has expanded and updated the model in various sectors in GREET 2022, and this report provides a summary of the release.

The GREET® (Greenhouse gases, Regulated Emissions, and Energy use in Technologies) model has been developed by Argonne National Laboratory (Argonne) with the support of the U.S. Department of Energy (DOE). GREET is a life-cycle analysis (LCA) tool, structured to systematically examine the energy and environmental effects of a wide variety of transportation fuels and vehicle technologies in major transportation sectors (i.e., road, air, marine, and rail) and other end-use sectors, and energy systems. Within the transportation sector, GREET covers road, air, water, and rail transportation sub-sectors. Recently, GREET was expanded to cover the building sector. Historically, GREET includes LCA of various materials such as steel, aluminum, cement, and different plastic types. Argonne has expanded and updated the model in various sectors in GREET 2021, and this report provides a summary of the release.