Hexbyte Glen Cove Computing carbon storage: Researchers identifies factors for safe and effective carbon capture and storage

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Left: Subsurface CO2 storage. Right: CO2 migration pattern in a digitized rock sample obtained from pore-scale two-phase flow simulation. The simulation was carried out on the Frontera supercomputer. Credit: Sahar Bakhshian, University of Texas at Austin

The road to a stabilized climate is challenging and contentious. A number of solutions will be needed to enable a fast, equitable transition away from fossil fuels: among them the development of sustainable energy sources, greener materials, and methods to remove CO₂ from the atmosphere.

One of the removal methods scientists are exploring is known as and storage (CCS). In carbon capture and storage, CO₂ is captured from industrial sources and injected into deep geological reservoirs underground, theoretically for thousands of years, in much the way water is stored in aquifers.

Sahar Bakhshian, a researcher at the University of Texas at Austin’s Bureau of Economic Geology, recently used supercomputers at the Texas Advanced Computing Center (TACC) to fundamentally understand how CO₂ storage works at the level of micrometer-wide pores in the rock, and to determine the characteristics and factors that can help optimize how much CO₂ can be stored.

Writing in the International Journal of Greenhouse Gas Control in December 2021, she explored the trapping efficiency of CO₂ through dissolving the gas into the resident brine in saline aquifers.

“We tried different scenarios—using different injection rates and fluid-rock properties—to determine how the properties affect what percentage of injected CO₂ can ideally be trapped by the dissolution mechanism,” she explained.

She found that two factors greatly impacted the amount of CO₂ that could be stored in the spaces within the rocks: wettability (or how well CO₂ molecules stick to the surface of the rock); and injection rate (the speed at which supercritical CO₂ is pushed into the reservoir).

Another effective process that ensures the security of CO₂ storage is capillary trapping, which happens when CO₂ pinches off and becomes immobilized in the pore space by capillary forces. In a study published in Advances in Water Resources in April 2019, Bakhshian presented the results of pore-scale, two-phase flow simulations that used digital versions of real rocks from a CO₂ storage test-site in Cranfield, Mississippi to explore how CO₂ migrated through the rock’s pore structure during the injection stage and how it can be trapped as immobilized blobs in the pore space during post-injection.

Bakhshian’s work is done under the auspices of the Gulf Coast Carbon Center (GCCC), which has been working on understanding the potential, risks, and best methods for geologic carbon storage since 1998.

CO2 flow inside the pore space of a millimeter-sized rock sample, which is initially filled with brine. This high-resolution fluid dynamics simulation demonstrates the migration pathway of CO2 when injected into saline reservoirs. Credit: Sahar Bakhshian, University of Texas at Austin

Supercomputers are one of the key tools that geoscientists have at their disposal to study processes relevant to carbon capture and storage, according to Bakhshian. “Computational fluid dynamics techniques are essential for this field, to better screen suitable target reservoirs for CO₂ storage, and predict the behavior of CO₂ plumes in these reservoirs,” she said.

Understanding the dynamics of storage capacity at the level of the pore through high performance computing simulations provides one lens into how carbon capture and storage could be achieved on a large scale.

“Our research is basically trying to characterize geologic settings suitable for storage and exploring the way we inject CO₂ to make sure it’s safe, effective and poses no threat to people or groundwater resources,” said Bakhshian.

Another aspect of Bakhshian’s research involves using machine learning techniques to develop computationally fast models that can estimate the storage capacity of reservoirs and assist with the environmental monitoring of CO₂.

Writing in Environmental Science and Technology in October 2021, Bakhshian proposed a deep learning framework to detect anomalies in soil gas concentration sensor data. The model was trained on data acquired from sensors being used for environmental characterization at a prospective CO₂ storage site in Queensland, Australia.

Bakhshian’s method, which incorporates processes based on natural soil respiration into a deep learning framework, was able to detect anomalies in the sensor data that, in future applications, could represent either sensor errors or leakages.

“Having a trustworthy real-time anomaly detection framework that is trained using the streaming sensor data and guided by a process-based methodology could help facilitate environmental monitoring in future projects,” Bakhshian said.

According to the Global CCS Institute, the U.S. is one of the nations with the greatest potential for geologic CO₂ . Though some environmentalists argue that CCS is simply a way for energy companies to continue to extract , others, including the International Panel on Climate Change, include CCS as one of the ways the global community can achieve net-zero emissions by mid-century.

“It’s safe and effective,” said Bakhshian. “And computing will help us find economical ways to achieve this goal.”

More information:
Sahar Bakhshian, Dynamics of dissolution trapping in geological carbon storage, International Journal of Greenhouse Gas Control (2021). DOI: 10.1016/j.ijggc.2021.103520

Computing carbon storage: Researchers identifies factors for safe and effective carbon capture and storage (2022, February 10)
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Hexbyte Glen Cove Plastic recycling results in rare metals being found in children's toys and food packaging thumbnail

Hexbyte Glen Cove Plastic recycling results in rare metals being found in children’s toys and food packaging

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Dr Andrew Turner. Credit: University of Plymouth

Some of the planet’s rarest metals—used in the manufacture of smartphones and other electrical equipment—are increasingly being found in everyday consumer plastics, according to new research.

Scientists from the University of Plymouth and University of Illinois at Urbana-Champaign tested a range of new and used products including children’s toys, office equipment and cosmetic containers.

Through a number of detailed assessments, they examined levels of rare earth elements (REEs) but also quantities of bromine and antimony, used as flame retardants in electrical equipment and a sign of the presence of recycled electronic .

The results showed one or more REEs were found in 24 of the 31 products tested, including items where unregulated recycling is prohibited such as single-use food packaging.

They were most commonly observed in samples containing bromine and antimony at levels insufficient to effect flame retardancy, but also found in plastics where those chemicals weren’t present.

Having also been found in beached marine plastics, the study’s authors have suggested there is evidence that REEs are ubiquitous and pervasive contaminants of both contemporary and historical consumer and environmental plastics.

The study, published in Science of the Total Environment, is the first to systematically investigate the full suite of REEs in a broad range of consumer plastics.

While they have previously been found in a variety of environments—including , soils and the atmosphere—the study demonstrates the wide REE contamination of the “plastisphere” that does not appear to be related to a single source or activity.

Dr. Andrew Turner, Associate Professor (Reader) in Environmental Sciences at the University of Plymouth and the study’s lead author, said: “Rare earth elements have a variety of critical applications in modern electronic equipment because of their magnetic, phosphorescent and electrochemical properties. However, they are not deliberately added to plastic to serve any function. So their presence is more likely the result of incidental contamination during the mechanical separation and processing of recoverable components.

“The health impacts arising from chronic exposure to small quantities of these metals are unknown. But they have been found in greater levels in food and tap water and certain medicines, meaning plastics are unlikely to represent a significant vector of exposure to the general population. However, they could signify the presence of other more widely known and better-studied chemical additives and residues that are a cause for concern.”

The research is the latest work by Dr. Turner examining the presence of toxic substances within everyday consumer products, marine litter and the wider environment.

In May 2018, he showed that hazardous chemicals such as bromine, antimony and lead are finding their way into food-contact items and other everyday products because manufacturers are using recycled electrical equipment as a source of black plastic.

His work was part of a successful application by the University to earn the Queen’s Anniversary Prize for Higher and Further Education for its pioneering research on microplastics pollution.

It also builds on previous work at the University, which saw scientists blend a smartphone to demonstrate quantities of rare or so-called ‘conflict’ elements in each product.

More information:
Andrew Turner et al, Rare earth elements in plastics, Science of The Total Environment (2021). DOI: 10.1016/j.scitotenv.2021.145405

Plastic recycling results in rare metals being found in children’s toys and food packaging (2021, February 17)
retrieved 18 February 2021
from https://phys.org/news/2021-02-plastic-recycling-results-rare-metals.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private

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