19 research outputs found
Large-scale production and transport of hydrogen from Norway to Europe and Japan: Value chain analysis and comparison of liquid hydrogen and ammonia as energy carriers
Get PDFLow-carbon hydrogen is considered as one of the key measures to decarbonise continental Europe and Japan. Northern Norway has abundant renewable energy and natural gas resources which can be converted to low-carbon hydrogen. However, Norway is located relatively far away from these markets and finding efficient ways to transport this hydrogen to the end-user is critical. In this study, liquefied hydrogen (LH2) and ammonia (NH3), as H2-based energy carriers, are analysed and compared with respect to energy efficiency, CO2 footprint and cost. It is shown that the LH2 chain is more energy efficient and has a smaller CO2 footprint (20 and 23 kg-CO2/MWhth for Europe and Japan, respectively) than the NH3 chain (76 and 122 kg-CO2/MWhth). Furthermore, the study finds the levelized cost of hydrogen delivered to Rotterdam to be lower for LH2 (5.0 EUR/kg-H2) compared to NH3 (5.9 EUR/kg-H2), while the hydrogen costs of the two chains for transport to Japan are in a similar range (about 7 EUR/kg-H2). It is also shown that under optimistic assumptions, the costs associated with the LH2 chain (3.2 EUR/kg-H2) are close to meeting the 2030 hydrogen cost target of Japan (2.5 EUR/kg-H2). Keywords Techno-economic analysisLiquid hydrogenAmmoniaLong distance transportacceptedVersio
Comparison of technologies for CO2 capture from cement production—Part 1: Technical evaluation
Get PDFA technical evaluation of CO 2 capture technologies when retrofitted to a cement plant is performed. The investigated technologies are the oxyfuel process, the chilled ammonia process, membrane-assisted CO 2 liquefaction, and the calcium looping process with tail-end and integrated configurations. For comparison, absorption with monoethanolamine (MEA) is used as reference technology. The focus of the evaluation is on emission abatement, energy performance, and retrofitability. All the investigated technologies perform better than the reference both in terms of emission abatement and energy consumption. The equivalent CO 2 avoided are 73–90%, while it is 64% for MEA, considering the average EU-28 electricity mix. The specific primary energy consumption for CO 2 avoided is 1.63–4.07 MJ/kg CO 2 , compared to 7.08 MJ/kg CO 2 for MEA. The calcium looping technologies have the highest emission abatement potential, while the oxyfuel process has the best energy performance. When it comes to retrofitability, the post-combustion technologies show significant advantages compared to the oxyfuel and to the integrated calcium looping technologies. Furthermore, the performance of the individual technologies shows strong dependencies on site-specific and plant-specific factors. Therefore, rather than identifying one single best technology, it is emphasized that CO 2 capture in the cement industry should be performed with a portfolio of capture technologies, where the preferred choice for each specific plant depends on local factors
Modeling of post-combustion carbon capture in power plants and process industries - partial capture and load following conditions
No full textCarbon capture and storage (CCS) is recognized as a potent technology for the mitigation of global warming, since it can significantly reduce CO2 emission from large point source emitters. Post-combustion CO2 capture using chemical absorption is a versatile end-of-pipe technology that can be implemented at all point sources of CO2, such as a power production facility or industrial plant. The increasing capacities of intermittent renewable sources in the energy system, such as wind and solar power, mean that fossil-fueled power generation faces a two-fold challenge: to supply regulating power and other ancillary services with increased flexibility while operating with near-zero emissions of CO2. Industrial plants generally operate under more stable conditions, and the main challenge for energy-intensive industries is to meet their long-term CO2 emission reduction targets, given that the possibilities for fuel substitution and further process optimization are limited in many cases and thus CCS will be required to meet this challenge.
The overall aim of this work was to evaluate operational strategies for efficient application of post-combustion CO2 capture to reduce emissions of CO2 from fossil fuel combustion, while meeting the demands of an energy system with large shares of renewable energy. This involved a steady-state investigation of CO2 capture (with the focus on partial capture of CO2) in three separate industrial applications: a pulp mill; an aluminum mill; and an oil refinery. Furthermore, CO2 capture in load-following power generation under transient conditions was investigated.
It is shown that the concentration of CO2 in the flue gas has a strong effect on capture process performance and that the design of the absorber temperature profile becomes increasingly important at high concentrations of CO2during absorption based on monoethanolamine (MEA), which, compared to ammonia, has high reactivity and a high heat of reaction. This is further illustrated by the three industrial case studies performed in this work, in which the flow conditions and exhaust composition differed significantly between the industrial plants. The results suggest that it may be unfeasible to aim for a high overall capture rate at plant sites because they usually consist of several CO2 sources, some of which may not be suitable for CO2 capture. Opportunities for waste heat utilization also vary considerably across the industrial plants, which further emphasizes the importance of case-specific studies.
The evaluation of the impacts of transient power plant operation on the capture unit included two load-change scenarios: the transitions to part-load and peak-load operations, respectively, from design conditions of full load. Simulations of the load-variation scenarios reveal that the implementation of active control strategies improves capture system performance with respect to transition rate, capture efficiency, and the heat requirement, for both part-load and peak-load operations. Integration of the capture process results in decreases in electric efficiency of around 9 percentage points at full load and in the range of 5–12 percentage points for off-design conditions, i.e., under part-load and peak-load conditions, respectively
Potential impact of the Preem CCS project
Get PDFThe ongoing Preem CCS project investigates opportunities for CO2 capture from the Preem refineries in Lysekil and Gothenburg, Sweden, with focus on the Lysekil refinery. The consortium members of this Norwegian-Swedish collaboration are Preem AB, Chalmers University of Technology, SINTEF Energy Research, Equinor Energy and Aker Carbon Capture. In this paper, we present the alternative carbon capture and storage (CCS) value chains that are being studied, together with the potential amounts of direct CO2 emissions from production that can be captured in each case. We also discuss potential cost reduction factors for CO2 capture at the Preem refineries, such as heat integration within the refinery and economies of scale, which may also be of relevance for reduction of capture costs for other Northern Lights partners. The implementation of CO2 capture in the Preem refineries will be an important step not only for Preem but also for Sweden to reach their climate neutrality goals
Liquid hydrogen as prospective energy carrier: A brief review and discussion of underlying assumptions applied in value chain analysis
Get PDFIn the literature, different energy carriers are proposed in future long-distance hydrogen value chains. Hydrogen can be stored and transported in different forms, e.g. as compressed dense-phase hydrogen, liquefied hydrogen and in chemically bound forms as different chemical hydrides. Recently, different high-level value chain studies have made extrapolative investigations and compared such options with respect to energy efficiency and cost. Three recent journal papers overlap as the liquid hydrogen option has been considered in all three studies. The studies are not fully aligned in terms of underlying assumptions and battery limits. A comparison reveals partly vast differences in results for chain energy efficiency for long-distance liquid hydrogen transport, which are attributable to distinct differences in the set of assumptions. Our comparison pinpoints the boiloff ratio, i.e. evaporation losses due to heat ingress, in liquid hydrogen storage tanks as the main cause of the differences, and this assumption is further discussed. A review of spherical tank size and attributed boiloff ratios is presented, for existing tanks of different vintage as well as for recently proposed designs. Furthermore, the prospect for further extension of tanks size and reduction of boiloff ratio is discussed, with a complementary discussion about the use of economic assumptions in extrapolative and predictive studies. Finally, we discuss the impact of battery limits in hydrogen value chain studies and pinpoint knowledge needs and the need for a detailed bottom-up approach as a prerequisite for improving the understanding for pros and cons of the different hydrogen energy carriers
