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Summary: The Fischer‐Tropsch synthesis is considered to be an alternative process to produce liquid hydrocarbons in an environmentally sustainable way by using synthesis gas obtained from renewable resources. The combination of acid catalysts, such as zeolites, with Fischer‐Tropsch catalysts could lead to an increase in the selectivity to an specific range of hydrocarbons, such as synthetic paraffinic kerosene. Therefore, the conversion of synthesis gas in hydrocarbons within kerosene range using catalytic dual beds formed by a potassium‐cobalt‐promoted iron and zeolites H‐ZSM‐5 and H‐ZSM‐12 has been studied. The reactions have been carried out at 250°C, 20 bar in a stacked fixed dual bed using synthesis gas with a H2:CO molar ratio of 2 during 60 hours. The selectivity towards C9‐C16 hydrocarbons was increased from 25% using the FT catalyst without zeolite, and up to 30% by using zeolites H‐ZSM‐5 or H‐ZSM‐12 with a Si/Al of 30 and 60, respectively. The results allowed the development of a reaction scheme suitable to design a tunable process for the synthesis gas conversion. [ABSTRACT FROM AUTHOR]

Calcium sulfoaluminate‐based cements (CSA) are proposed as a cement alternative with a low carbon footprint. The nature of CSA makes the manufacturing process to require lower temperature, less fuel, and less calcite. However, it requires aluminum oxide, Al2O3, which would be originated from bauxite and bauxite‐derived wastes, and sulfur, coming from calcium sulfate or elemental sulfur. An eco‐efficiency assessment of CSA cements, benchmarked against the conventional Portland cement, has been performed following the principles of ISO 14045 on eco‐efficiency for a total of 240 CSA clinker production scenarios. The eco‐efficiency indicator relates an environmental indicator with a product system value indicator, and it is calculated for each of the studied parameters: bauxite geographical origin, the fuel used for clinkering, the source of sulfur, and the composition of the clinker. Eco‐efficiency results show a strong dependence on the origin of bauxite, while other parameters, as the fuel used, its content in sulfur, or the supply of other raw materials, are of less importance. The most eco‐efficient solutions are those with certain closeness to bauxite sources. To achieve global solutions, that is, cement‐making based on CSA independently of the origin of the raw materials, the amount of bauxite needs to be minimized and CSA composition restricted. [ABSTRACT FROM AUTHOR]

In this article we address the environmental assessment of the coprocessing of biomass‐based feedstock in crude oil refineries. In particular, we consider the coprocessing of bio‐oil (from the pyrolysis of lignocellulosic biomass) in fluid catalytic cracking and hydrocracking units, and the cogasification of pyrolysis char (coproduced with bio‐oil) with coke. In addition to a conventional fossil‐based refinery used as the base case, we simulate three alternative case studies including different biofeedstock coprocessing layouts based on original models validated against experimental data. We use process simulation as a primary source of data for the life‐cycle assessment (LCA) of each case study. The LCA results show that the system's carbon footprint per energy output is improved when including biofeedstock coprocessing, favoring the study with the highest biofeedstock use. However, the results for other life‐cycle indicators such as the abiotic depletion of elements and eutrophication lead to unfavorable results for biofeedstock coprocessing, which is mainly due to the increased use of catalysts and the need for fertilizers. Hence, the suitability of a specific coprocessing layout will be ultimately conditioned by the performance indicators prioritized by the actors involved in the decision‐making process. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]

The subnational level embodied by regions and cities presents unique challenges for energy policy. Large metropolitan areas tend to be consumers rather than producers of energy, with two of the most critical sectors being transport and residential. The Madrid region in Spain – one of Europe's most significant urban areas – represents such a phenomenon. The Long-Range Energy Alternatives Planning System (LEAP) modelling approach has been applied to Madrid for long-term sustainable energy planning. This paper presents the model, a business-as-usual projection and two alternate scenarios to 2050. The results show that by applying measures to decarbonize the transport and residential sectors, significant reductions in energy demand are possible. [ABSTRACT FROM AUTHOR]

CO2 capture and storage involves technologies that separate, capture, and store CO2 from large facilities, such as fossil fuel power plants. Although it is a promising measure to meet environmental standards on carbon pollution, proposed technologies in power plants are energy demanding and decrease the energy generated per unit of input fuel when compared to business-as-usual scenarios. In this paper, we evaluate the environmental performance of two similarly structured combined-cycle power plants with pre-combustion capture. The first power plant performs methane steam reforming in an autothermal reformer, while the second plant uses a reactor that includes a hydrogen-separating membrane. The two plants are compared both to one another and to a business-as-usual scenario using six environmental impact potentials (abiotic depletion, global warming, ozone layer depletion, photochemical oxidant formation, acidification, and eutrophication). The goal is to pinpoint environmental weaknesses and strengths of the two capture technologies. We find that the two plants result in similar impacts, decreasing the contribution to global warming of conventional operation but, at the same time, increasing other impacts, such as ozone layer depletion and photochemical oxidant formation. Additionally, the two capture plants result in higher cumulative non-renewable and total energy demands, as well as in lower life-cycle energy balances and efficiencies. The most direct measure to decrease the environmental impacts of the examined techniques would be to increase their efficiency, by decreasing the requirements of the processes in natural and energy resources.© 2014 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]