2,068 research outputs found

    Carbon neutral manufacturing via on-site CO2 recycling.

    Get PDF
    The chemical industry needs to significantly decrease carbon dioxide (CO2) emissions in order to meet the 2050 carbon neutrality goal. Utilization of CO2 as a chemical feedstock for bulk products is a promising way to mitigate industrial emissions; however, CO2-based manufacturing is currently not competitive with the established petrochemical methods and its deployment requires creation of a new value chain. Here, we show that an alternative approach, using CO2 conversion as an add-on to existing manufactures, can disrupt the global carbon cycle while minimally perturbing the operation of chemical plants. Proposed closed-loop on-site CO2 recycling processes are economically viable in the current market and have the potential for rapid introduction in the industries. Retrofit-based CO2 recycling can reduce annually between 4 and 10 Gt CO2 by 2050 and contribute to achieving up to 50% of the industrial carbon neutrality goal

    Stochastic-optimization of equipment productivity in multi-seam formations

    Get PDF
    Short and long range planning and execution for multi-seam coal formations (MSFs) are challenging with complex extraction mechanisms. Stripping equipment selection and scheduling are functions of the physical dynamics of the mine and the operational mechanisms of its components, thus its productivity is dependent on these parameters. Previous research studies did not incorporate quantitative relationships between equipment productivities and extraction dynamics in MSFs. The intrinsic variability of excavation and spoiling dynamics must also form part of existing models. This research formulates quantitative relationships of equipment productivities using Branch-and-Bound algorithms and Lagrange Parameterization approaches. The stochastic processes are resolved via Monte Carlo/Latin Hypercube simulation techniques within @RISK framework. The model was presented with a bituminous coal mining case in the Appalachian field. The simulated results showed a 3.51% improvement in mining cost and 0.19% increment in net present value. A 76.95ydÂł drop in productivity per unit change in cycle time was recorded for sub-optimal equipment schedules. The geologic variability and equipment operational parameters restricted any possible change in the cost function. A 50.3% chance of the mining cost increasing above its current value was driven by the volume of material re-handled with 0.52 regression coefficient. The study advances the optimization process in mine planning and scheduling algorithms, to efficiently capture future uncertainties surrounding multivariate random functions. The main novelty includes the application of stochastic-optimization procedures to improve equipment productivity in MSFs --Abstract, page iii

    Improving Confidence in Evolutionary Mine Scheduling via Uncertainty Discounting

    Full text link
    Mine planning is a complex task that involves many uncertainties. During early stage feasibility, available mineral resources can only be estimated based on limited sampling of ore grades from sparse drilling, leading to large uncertainty in under-sampled parts of the deposit. Planning the extraction schedule of ore over the life of a mine is crucial for its economic viability. We introduce a new approach for determining an "optimal schedule under uncertainty" that provides probabilistic bounds on the profits obtained in each period. This treatment of uncertainty within an economic framework reduces previously difficult-to-use models of variability into actionable insights. The new method discounts profits based on uncertainty within an evolutionary algorithm, sacrificing economic optimality of a single geological model for improving the downside risk over an ensemble of equally likely models. We provide experimental studies using Maptek's mine planning software Evolution. Our results show that our new approach is successful for effectively making use of uncertainty information in the mine planning process

    GHG Accounting for Low-emissions Branded Steel and Aluminum Products

    Get PDF
    Iron, steel, and aluminum products are major sources of GHG emissions, and these emissions have traditionally been hard to abate. As of 2020, the iron and steel and the aluminum industries accounted for 7% and 3% of global GHG emissions respectively. In recent years, demand has increased substantially for “green” iron, steel, and aluminum products which can allow purchasing companies to reduce their reported upstream scope 3 GHG emissions. In response to increased demand, companies in these industries have made an expanding array of green products available to customers. “GHG Accounting for Low-emissions Branded Steel and Aluminum Products,” draws from an original analysis of over a dozen steel and aluminum low carbon brands and argues that while green-branded products can play a role in incentivizing and supporting the expansion of green procurement, they exist in a market that lacks the transparent, harmonized system for emissions accounting necessary to drive broad-based emissions reductions in the materials sector. This paper provides concrete steps to achieving a transparent and cohesive green market for low-emissions branded steel and aluminum products

    Supply Chains and Porous Boundaries: The Disaggregation of Legal Services

    Get PDF
    The economic downturn has had significant effects on law firms, and is causing many of them to rethink some basic assumptions about how they operate. In important respects, however, the downturn has simply intensified the effects of some deeper trends that preceded it, which are likely to continue after any recovery that may occur. This paper explores one of these trends, which is corporate client insistence that law firms “disaggregate” their services into discrete tasks that can be delegated to the least costly providers who can perform them. With advances in communications technology, there is increasing likelihood that some of these persons may be located outside the formal boundaries of the firm. This means that law firms may need increasingly to confront the make or buy decision that their corporate clients have regularly confronted for some time. The potential for vertical disintegration is a relatively recent development for legal services, but is well-established in other sectors of the global economy. Empirical work in several disciplines has identified a number of issues that arise for organizations as the make or buy decision becomes a potentially more salient feature of their operations. Much of this work has focused in particular on the implications of relying on outsourcing as an integral part of the production process. This paper discusses research on: (1) the challenges of ensuring that work performed outside the firm is fully integrated into the production process; (2) coordinating projects for which networks of organizations are responsible; (3) managing the transfer of knowledge inside and outside of firms that are participants in a supply chain; and (4) addressing the impact of using contingent workers on an organization’s workforce, structure, and culture. A review of this research suggests considerations that law firms will need to assess if they begin significantly to extend the process of providing services beyond their formal boundaries. Discussing the research also is intended to introduce concepts that may become increasingly relevant to law firms, but which currently are not commonly used to analyze their operations. Considering how these concepts are applicable to law firms may prompt us to rethink how to conceptualize these firms and what they do. This paper therefore is a preliminary attempt to explore: (1) the extent to which law firms may come to resemble the vertically disintegrated organizations that populate many other economic sectors and (2) the potential implications of this trend for the provision of legal services,the trajectory of legal careers, and lawyers’ sense of themselves as members of a distinct profession

    Multi-Sector General Permit

    Get PDF
    In compliance with the provisions of the Clean Water Act (CWA), as amended (33 U.S.C. 1251 et seq.), operators of stormwater discharges associated with industrial activity located in an area identified in Appendix C where EPA is the permitting authority are authorized to discharge to waters of the United States in accordance with the eligibility and Notice of Intent (NOI) requirements, effluent limitations, inspection requirements, and other conditions set forth in this permit

    An integrated process for biomass pyrolysis oil upgrading: A synergistic approach

    Get PDF
    Biomass pyrolysis is a promising path toward renewable liquid fuels. However, the calorific value of the pyrolysis oil (PO), also known as bio-oil, is low due to the high content of organic oxygenates and water. The oxygen content of PO can be reduced by hydrodeoxygenation, in which hydrogen is used to remove oxygen. An economic disadvantage of hydrodeoxygenation pathway is its dependence on hydrogen as an expensive feedstock. An alternative technology is to upgrade PO in hot, high pressure water, known as hydrothermal processing. The present paper studies upgrading pyrolysis oil derived from Norwegian spruce by (1) hydrodeoxygenation in a liquid hydrocarbon solvent using nanodispersed sulphide catalysts and (2) hydrothermal treatment in near-supercritical water. Experimental results and simulation studies suggested that if water soluble products are reformed for hydrogen production, the hydrodeoxygenation pathway would be a net consumer of hydrogen, whilst the hydrothermal pathway could produce a significant hydrogen excess. By comparison, the fuel yield from hydrodeoxygenation was significantly higher than hydrothermally treated fuel. Therefore, in the present study, an integrated model was proposed which demonstrates that the synergistic integration of hydrothermal and hydrodeoxygenation upgrading technologies can yield an optimal configuration which maximises fuel production, whilst obviating the need to purchase hydrogen. In this optimal configuration, 32% of raw pyrolysis-oil is hydrothermally treated and the rest is sent for hydrodeoxygenation. The results of a techno-economic analysis suggests that if the proposed integrated approach is used, it is possible to produce biofuel (43% gasoline, and 57% diesel) at a very competitive minimum selling price of 428 m−3(1.62 m−3 (1.62 /gallon)

    Plant-Wide Energy Efficiency Assessment at the Arizona Portland Cement Plant in Rillito, Arizona

    Full text link

    Analysis of Energy-Efficiency Opportunities for the Cement Industry in Shandong Province, China

    Full text link

    Energy efficiency and pollution prevention assessment protocol in the polymer processing industries. Final report

    Full text link
    • 

    corecore