The Co-Optimization of Fuels and Engines (Co-Optima) is a research and development consortia funded by the U.S. Department of Energy, which has engaged partners from national laboratories, universities, and industry to conduct multidisciplinary research at the intersection of biofuels and combustion sciences. Since 2016, the Co-Optima team has examined high-quality bioblendstocks, and their properties, as design variables for increasing efficiency in modern engines while decarbonizing on-road light- and heavy-duty vehicles. The objective of this analysis is to combine and expand upon research into Co-Optima multi-mode bioblendstocks, which blend with petroleum gasoline to form high efficiency fuels for combustion in both spark ignition and advanced compression ignition engines. Consequently, the economic and environmental impacts of deploying 10 different multi-mode bioblendstocks derived from renewable and circular resources are quantified. Each bioblendstock is evaluated across several variables including (1) target blend levels of 10, 20, and 30 vol %, (2) years from 2030 to 2050, (3) crude oil benchmark prices, (4) vehicle lifetime miles, and (5) incremental vehicle costs. A Monte Carlo simulator is developed using a refinery optimization model and life-cycle analysis tool from prior Co-Optima research to sample marginal abatement costs of CO2, or cost of removing an additional unit of CO2, corresponding to each bioblendstock while considering input variable uncertainties. Results show that the combination of efficiency gains from advanced multi-mode fuel-engine technologies and the reoptimization of refinery operations results in several bioblendstocks demonstrating near-zero expected marginal abatement costs. Variable importances are also explored to highlight which aspects of the multi-mode technology are most influential in determining marginal abatement costs. Results suggest that Co-Optima multi-mode technology could provide economically viable decarbonization contributions to electrification-resistant light-duty vehicle sectors or near-term emission reductions, while Co-Optima fuels or alternatives decarbonize further to reach net-zero status.
The world-class Sarbai, Kachar and Sokolovsk iron ore deposits of the Turgai belt, in the Carboniferous Valerianovskoe arc of northwest Kazakhstan, contain an aggregate of more than 3 billion tonnes of mineable massive magnetite. The Valerianovskoe arc is the possible westward extension to the South Tien Shan arc that is host to the giant Almalyk Cu-Au porphyry system in Uzbekistan. The magnetite bodies of the Turgai belt replace limestone and tuffs, and are distal to locally proximal to the contacts of gabbro-diorite-granodiorite intrusive complexes. Three main stages of alteration and mineralisation can be recognised at these deposits, namely: (1) pre-ore; (2) the main magnetite forming; and (3) post ore phases. The pre-ore stage is characterised by high temperature, metamorphic/metasomatic calc- and alumino-silicates. The main magnetite ore phase formed when hot, sulphur poor, acidic, iron-, silica- and aluminium rich fluids were structurally focused to dissolve and replace the dominantly limestone hosts. This was accompanied by a skarn assemblage gangue of epidote, calcic-pyroxenes, calcic-garnet and calcic-amphiboles, minor sulphide minerals and high field strength element (HFSE)-bearing accessory minerals such as titanite and apatite. This magnetite-skarn
mineralisation was followed by a late sulphide phase, when comparatively cooler fluids, which produced distinctive and extensive alteration assemblages of sodium-rich scapolite, albite, chlorite and K feldspar, accompanied by chalcopyrite, pyrite and minor sphelarite and galena. The post-ore phase, is characterised by cross cutting barren veins composed of calcite, lesser albite and K feldspar, and minor quartz, and by widespread alteration comprising scapolite, albite and silica, which surrounds the deposit, and extends for several kilometers into the host rock. Many of the geological and mineralogical features of these deposits closely resemble those of IOCG deposits and provinces around the world.
However, as the copper sulphide mineralisation is sub-economic, they may only be classified as either IOCG-style or IOCG-related deposits. Stable isotope (C, O, S) studies have been carried out on a range of sulphides, carbonates and silicates related to the mineralisation. Preliminary results from sulphides intergrown with magnetite support a magmatic source for the sulphur. Oxygen isotope data from associated silicates and iron oxides also support an igneous, or igneous rock equilibrated source for the mineralising fl uids. Carbon and oxygen isotope data from gangue carbonates suggest
carbonate is derived from the interaction of igneous-derived or igneous-equilibrated fl uids with host limestones.
Abstract New road cuttings have exposed a large part of the Merioneth Series. The rocks are low‐grade thinly layered metasediments which have undergone extensive buckling resulting in tectonic ripples, mullions, and crenulations. It is suggested that the periclinal form of these structures may be the result of buckling layered sequences with longitudinal and transverse zones of constraint (heterogeneities). The process is analogous to ‘quilting’ of thin metal sheets and the heterogeneities are perhaps due to layer thickness variation. There are two foliations; which may form a progressive sequence of cleavage development during the evolution of the fold style.
Understanding opportunities for carbon capture and storage (CCS) across sectors is important for choosing among greenhouse gas mitigation strategies. This study explores the cradle-to-gate life cycle environmental impacts of amine solvent based carbon capture systems on U.S. ammonia production, petroleum refineries, supercritical and subcritical pulverized coal power plants, and natural gas combined cycle plants. We use publicly available data to create comprehensive life cycle inventories for petroleum refining and ammonia production for 2014. We use these processes and additional modeled carbon capture processes to compare carbon capture on ammonia production and petroleum refining to inventories for coal and natural gas fired electricity with carbon capture. This analysis found that particulate matter formation potential, eutrophication potential, and water consumption increase in all sectors as a result of installation and operation of CCS technologies per kg CO2e abated, while the effect on acidification potential and particulate mater formation potential is mixed. The differences in tradeoffs among systems are driven primarily by three factors: the combustion emissions from fuel used to operate the capture unit, the upstream supply chain to obtain that fuel, and the relative impact of the carbon capture unit on baseline flue gas emissions (i.e. possible co-benefits from capture).
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.
