| 1. |
- Linderholm, Carl Johan, 1976, et al.
(författare)
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Chemical-looping combustion of solid fuel in a 100 kW unit using sintered manganese ore as oxygen carrier
- 2017
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 65, s. 170-181
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Tidskriftsartikel (refereegranskat)abstract
- Carbon capture and storage (CCS) offers the opportunity to avoid CO2 emissions from for example power plants and cement factories. Chemical-looping combustion (CLC) is one of the most promising capture technologies with potentially very low cost of CO2 capture. In this study we present findings from a solid-fuel 100 kW chemical-looping combustor. A new oxygen carrier - a sintered manganese ore called Sinaus - has been studied in the Chalmers 100 kW unit. The material has been investigated for an operational time of 51.5 h using five fuels: two bituminous coals, two types of wood char, and petcoke. The operational results clearly demonstrate the viability of the CLC process. In comparison to previously used iron-based oxygen carriers, the Sinaus material showed higher gas conversion - up to 88% - and lower loss of char to the air reactor, with carbon capture reaching as high as 100%. Furthermore, the solid-fuel conversion was higher, which is mainly an effect of the choice of fuel size. It was found that the choice of fuel has a crucial impact on performance. Previous experience has shown that the use of large fuel particles gives low carbon capture, whereas pulverized fuel leads to low solid-fuel conversion. By choosing the appropriate - intermediate - size of fuel, it is possible to combine high carbon capture with high solid-fuel conversion. Previous studies indicate that the drawback of many manganese ores is the mechanical stability. Hence, a lot of emphasis was put on an in-depth study of the lifetime of the Sinaus material. Analyzing the production rate of fines, it was found the expected lifetime of the Sinaus particles was 100-400 h. This is lower than what has been found for iron-based material, but most likely sufficient for operation in full-scale chemical-looping applications. Whilst the production of fines was highest during operation with fuel, a lot of fines were produced also during operation without fuel. Seven experiments without fuel, i.e when the observed mechanical degradation was only due to high-velocity impacts and not chemical stress caused by phase transformations, gave a lifetime in the interval 220-1230 h. In conclusion, this first-of-its-kind investigation shows that the lifetime of the oxygen carrier is related to both the change in oxygen-carrier conversion and high-velocity impacts.
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| 2. |
- Moldenhauer, Patrick, 1983, et al.
(författare)
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CO2 Capture from Combustion of Biomass Volatiles with a Chemical-Looping Combustion Process
- 2017
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Ingår i: EUBCE 2017 - 25th European Biomass Conference and Exhibition, Stockholm, Sweden, June 12-15, 2017.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Chemical-looping combustion (CLC) is a low-cost CO2 capture technology that uses oxygen carriers – metal oxides – for oxygen transfer from air to fuel. This enables fuel oxidation without mixing fuel and combustion air. After condensation of steam, a stream of pure CO2 is obtained without the need for an active gas separation. The capture and storage of CO2 from biomass-based fuels sources make it possible to obtain so-called negative emissions – the atmosphere is cleansed from carbon dioxide. This concept of storing biomass-based CO2 could prove to be highly instrumental for a country such as Sweden, which has substantial point emissions of biomass-based CO2.
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| 3. |
- Moldenhauer, Patrick, 1983, et al.
(författare)
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Oxygen carrier development of calcium manganite-based materials with perovskite structure for chemical looping combustion of methane
- 2017
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Ingår i: Proceedings of the 42nd International Technical Conference on Clean Energy, Clearwater, FL, USA, June 11-15, 2017. ; , s. 12-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Chemical-looping combustion (CLC) of gaseous fuels could be of interest in industrial processes for heat, power or hydrogen production with carbon capture. For instance, production of steam or hydrogen from refinery gas are possible applications. A series of collaborate European projects has been carried out since 2002, which focused on oxygen-carrier development and upscaling of both theCLC process and oxygen-carrier production with methane or natural gas as fuel. Most recently, in the FP7 SUCCESS project (2013-2017), Ca-Mn-based materials with perovskite structure, CaMnO3, were produced at a larger scale and with cheap and commercial raw materials. The main advantage with this type of oxygen carrier is the ability to release oxygen to the gas phase, hence promoting reactivity in the fuel reactor. In the project, a significant number of such materials were produced and tested. It was found that a perovskite structure can be obtained relatively easy with widely different raw materials for Ca, Mn, Ti and Mg. The produced materials generally had high reactivities and high attrition resistances, but were prone to sulfur poisoning.In this paper, selected results are presented from the different stages of material development and upscaling, i.e., from bench-scale reactors with batch and continuous operation, respectively, as well as from a laboratory-scale unit with continuous operation and a nominal fuel input of 10 kWth. In the 10 kW unit, the gas velocities in the riser and in the grid jet zone of the gas distributor come close to gas velocities of industrial-scale units and, therefore, this unit is used to assess particle lifetime. Results from the 10 kW unit show that very high degrees of fuel conversion can be reached while achieving very high lifetimes.
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| 4. |
- Skagestad, Ragnhild, 1978, et al.
(författare)
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GCCSI Webinar: Cutting Cost of CO2 Capture in Process Industry (CO2stCap) Project overview & first results for partial CO2 capture at integrated steelworks
- 2017
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- GCCSI Webinar: Cutting Cost of CO2 Capture in Process Industry (CO2stCap) Project overview & first results for partial CO2 capture at integrated steelworks This publication has the format of a webinar: The CO2StCap project is a four year initiative carried out by industry and academic partners with the aim of reducing capture costs from CO2 intensive industries (more information here). The project, led by Tel-Tek, is based on the idea that cost reduction is possible by capturing only a share of the CO2 emissions from a given facility, instead of striving for maximized capture rates. This can be done in multiple ways, for instance by capturing only from the largest CO2 sources at individual multi-stack sites utilising cheap waste heat or adapting the capture volumes to seasonal changes in operations. The main focus of this research is to perform techno-economic analyses for multiple partial CO2 capture concepts in order to identify economic optimums between cost and volumes captured. In total for four different case studies are developed for cement, iron & steel, pulp & paper and ferroalloys industries. The first part of the webinar gave an overview of the project with insights into the cost estimation method used. The second part presented the iron & steel industry case study based on the Lulea site in Sweden, for which waste-heat mapping methodology has been used to assess the potential for partial capture via MEA-absorption. Capture costs for different CO2 sources were discussed, demonstrating the viability of partial capture in an integrated steelworks.
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