| 11. |
- Biermann, Maximilian, et al.
(författare)
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Excess heat-driven carbon capture at an integrated steel mill : Considerations for capture cost optimization
- 2019
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Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier. - 1750-5836 .- 1878-0148. ; 91
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Tidskriftsartikel (refereegranskat)abstract
- Primary steelmaking in blast and basic oxygen furnaces is inherently carbon-intensive. Partial capture, i.e., capturing only a share of the CO2, is discussed as an option to reduce the cost of carbon capture and storage (CCS) and to realize a near-term reduction in emissions from the steel industry. This work presents a techno-economic assessment of partial capture based on amine absorption of CO2. The cost of steam from excess heat is assessed in detail. Using this steam to drive the capture process yields costs of 28–50 €/t CO2-captured. Capture of CO2 from the blast furnace gas outperforms end-of-pipe capture from the combined-heat-and-power plant or hot stove flue gases onsite by 3–5 €/t CO2-captured. The study shows that partial capture driven exclusively by excess heat represents a lower cost for a steel mill owner, estimated in the range of 15–30 €/t CO2-captured, as compared to full capture driven by the combustion of extra fuel. In addition, the full-chain CCS cost (capture, transport and storage) for partial capture is discussed in light of future carbon prices. We conclude that implementation of partial capture in the steel industry in the 2020s is possible and economically viable if policymakers ensure long-term regulation of carbon prices in line with agreed emission reduction targets beyond Year 2030.
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| 12. |
- Biermann, Max, 1989, et al.
(författare)
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Partial Carbon Capture by Absorption Cycle for Reduced Specific Capture Cost
- 2018
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 57:45, s. 15411-15422
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Tidskriftsartikel (refereegranskat)abstract
- For a sustainable-energy system, the industrial carbon emission should be zero or close to it. The partial capture of CO2, i.e., capturing only a share of the CO2, is discussed as an option for initiating the transition toward the decarbonization of industry by reducing the CO2 mitigation cost at industrial sites. This work models two approaches to achieving partial capture based on amine absorption: (1) capturing 90% CO2 from a split stream of the flue gas or (2) capturing less CO2 (≪90%) from the total flue-gas flow. A techno-economic analysis is carried out that considers scale, CO2 concentration, and process configurations (absorber intercooling and rich solvent splitting) when comparing the cost of partial capture to full capture, i.e., capturing close to all CO2 from the entire gas. Besides lowering absolute costs, the study shows that partial capture from CO2-rich gases may also lower specific cost (€ per tonne of CO2 captured) compared to full capture, despite the economy of scale, during certain market conditions. Operating expenditures, especially the cost of steam, are found to be dominating cost factors for partial capture, even for capture down to 200 000 tonnes per year.
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| 13. |
- Biermann, Max, 1989, et al.
(författare)
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Scenario for near-term implementation of partial capture from blast furnace gases in Swedish steel industry
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Iron-and-steel making is a carbon-intensive industry and responsible for about 8% of global CO2 emissions. Meeting CO2 reduction targets is challenging, since carbon is inherent in the dominating production route in blast furnaces. Long-term plans to phase out carbon and change production technique are under way, such as iron ore reduction with hydrogen[1][2] won from renewable energies or electro winning[3], however unlikely to be implemented at scale before 2040 [4]. Until a transition to such technologies is completed, carbon leakage will remain to be a threat to steel industry inside EU ETS system. CCS remains an option for steel industry to comply with reduction targets and meet rising allowance (EUA) prices, currently above 20 €/t. Most studies on CCS propose a capture rate of ≥ 90 %[5–7], however, CCS could be considered as a part of a series of measures (e.g. fuel change, energy efficiency measures) that together achieve a significant reduction in CO2 emissions until a carbon-neutral production is in place. This line of thought motivates the concept of partial capture, where only the most cost effective part of the CO2 emissions are separated for storage [8]. In steel industry, high CO2 concentrations at large flows and the availability of excess heat make partial capture attractive. Previous work on the steel mill in Luleå, Sweden, emits around 3.1 Mt CO2 per year, has found that 40-45 % of site emissions can be captured fueled by excess heat alone[9]. Therein, five heat recovery technologies were assessed, ranging from back pressure operation of CHP turbine to dry slag granulation. Promising CO2 sources on site include flue gases from hot stoves and the combined-heat and power plant, and the process gas originating from the blast furnace – blast furnace gas (BFG). BFG is a pressurized, low value fuel used for heating on site. CO2 separation from BFG requires less reboiler heat for MEA regeneration, and the enhanced heating value of the CO2 lean BFG increases energy efficiency of the steel mill [9]. This work discusses the near-term (the 2020s) implementation of partial capture at a Swedish steel mill and the economic viability of such implementation dependent on the energy price, carbon price, and required reductions in CO2 emissions. Based on previous work [9][10,11] on partial capture in steel industry a cost estimation of a capture system for the BFG is conducted including CAPEX and OPEX of the MEA capture unit, gas piping, and recovering heat from the steel mill. The costs are summarized as equivalent annualized capture cost (EAC) and set into relation to transport and storage costs as well as carbon emission costs to form the net abatement cost (NAC) according to Eq. (1) ???=???+ ?????????&??????? ???? −?????? ????? [€/???2] (1) Figure 1 shows how EAC for BFG varies with the capture rate and the cost of steam for different heat recovery technologies represented by the steps in the curve ( see explanation in [9]). Note that partial capture from BFG is more economical than the full capture benchmark. The most cost-efficient case of 28 €/t CO2 captured is achieved for BFG capture fueled by steam from back-pressure operation (at the expense of electricity production), flue gas heat recovery and flare gas combustion. The transport and storage cost applied in Eq (1) represent ship transport from the Bothnian Bay to a storage site in the Baltic Sea , according to Kjärstad et el.[12]. Transport and storage cost range within 17 – 27 €/t CO2 depending on scale. These installation and operation cost for capture, transport and storage are set into relation with various scenarios on future carbon and energy (electricity) prices in Europe and Sweden. For example, Figure 2 illustrates a scenario in line with IEA’s sustainable development scenario to restrict global warming to 2°C. The carbon prices are adapted from WEO 2018 [13] and increase from 20 € to 120 € per tonne CO2 by 2040 and the electricity prices of 42-52 €/MWh (increasing with time) are based on latest results from the NEPP project [14]. In this scenario, partial capture from BFG could become economic viable in 2029, construction in 2020 with operation from 2022/23 onwards is likely to pay off within a lifetime of 20 years only. This work demonstrates the viability of partial capture as cost-efficient mitigation measure for the steel industry and illustrates conditions for an early implementation in the 2020s. This work is part of the CO2stCap project (Cutting Cost of CO2 Capture in Process Industry) and funded by Gassnova (CLIMIT programme), the Swedish Energy Agency, and industry partners.
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| 14. |
- Cintas Sanchez, Olivia, 1982, et al.
(författare)
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Geospatial supply-demand modeling of biomass residues for co-firing in European coal power plants
- 2018
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Ingår i: GCB Bioenergy. - : Wiley. - 1757-1707 .- 1757-1693. ; 10:11, s. 786-803
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Tidskriftsartikel (refereegranskat)abstract
- Biomass co‐firing with coal is a near‐term option to displace fossil fuels and can facilitate development of biomass conversion and the build‐out of biomass supply infrastructure. A GIS‐based modeling framework (EU‐28, Norway, and Switzerland) is used to quantify and localize biomass demand for co‐firing in coal power plants and agricultural and forest residue supply potentials; supply and demand are then matched based on minimizing the total biomass transport costs (field‐to‐gate). Key datasets (e.g., land cover, land use, wood production) are available at 1,000 m or higher resolution, while some data (e.g., simulated yields) and assumptions (e.g., crop harvest index) have lower resolution and were re‐sampled to allow modeling at 1,000 m resolution. Biomass demand for co‐firing is estimated at 184 PJ in 2020, corresponding to an emissions reduction of 18 Mt CO2. In all countries except Italy and Spain, the sum of the forest and agricultural residues available at less than 300 km from a co‐firing plant exceeds the assessed biomass demand. The total cost of transporting residues to these plants is reduced if agricultural residues can be used, since transport distances are shorter. The total volume of forest residues less than 300 km from a co‐firing plant corresponds to about half of the assessed biomass demand. Almost 70% of the total biomass demand for co‐firing is found in Germany and Poland. The volumes of domestic forest residues in Germany (Poland) available within the cost range 2‐5 (1.5‐3.5) €/GJ biomass correspond to about 30% (70%) of the biomass demand. The volumes of domestic forest and agricultural residues in Germany (Poland) within the cost range 2‐4 (below 2) €/GJ biomass exceed the biomass demand for co‐firing. Half of the biomass demand is located within 50 km from ports, indicating that long‐distance biomass transport by sea is in many instances an option.
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| 15. |
- Cutz, Luis, 1986, et al.
(författare)
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A techno-economic assessment of biomass co-firing in Czech Republic, France, Germany and Poland
- 2019
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Ingår i: Biofuels, Bioproducts and Biorefining. - : Wiley. - 1932-1031 .- 1932-104X. ; 13:5, s. 1289-1305
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Tidskriftsartikel (refereegranskat)abstract
- Biomass co-firing with coal can help to reduce greenhouse gas emissions and can act as a low-cost stepping-stone for developing biomass supply infrastructures. This paper presents a techno-economic assessment of the biomass co-firing potential in coal-fired boilers in Czech Republic, France, Germany and Poland. The current coal power plant infrastructure is characterized by means of geographic location of the coal power plants, installed boiler capacity, type of boiler technology and year of commissioning, as extracted from the Chalmers Power Plant Database. The assessment considers type of boiler technology, type of biomass, co-firing fraction, implementation costs, breakeven prices for co-firing and an alkali index to determine the risk of high-temperature corrosion. The main factors affecting the co-firing potential are the biomass price, carbon price and alkali index. Results indicate that the total co-firing potential in the four countries is around 16 TWh year−1, with the largest potential from a conversion perspective in Germany, followed by Poland. Biomass co-firing with coal is estimated to be competitive at biomass prices below 13 € MWhinput−1 when the carbon price is 20 € t−1 CO2. On average, 1 TWh of electricity from biomass co-firing substitutes 0.9 Mt of fossil CO2 emissions. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.
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| 16. |
- Cutz, Luis, 1986, et al.
(författare)
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Assessment of biomass energy sources and technologies: The case of Central America
- 2016
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 58, s. 1411-1431
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Forskningsöversikt (refereegranskat)abstract
- This paper reviews and assesses conditions for increased and efficient use of biomass in Central America (CA), providing an overview of conditions for biomass supply in each country. Then, a Fuzzy Multi-Actor Multi-Criteria Decision-Making (MCDM) method is applied to identify a portfolio of biomass conversion technologies appropriate for CA, considering technical, economic, environmental and socio-political aspects. The work is motivated by the relatively large availability of biomass in CA at the same time as current conversion of biomass is carried out in inefficient processes. The assessment of technologies includes thermochemical processes (pyrolysis, combustion and gasification) for production of different energy carriers, including improved cooking stoves (ICSs). The most promising biomass feedstocks in the region are residue based; animal (manure), forest and agricultural origin. We show that around 250 PJ/year could be available for the energy sector, which is equivalent to 34% of primary energy supply for CA. It is concluded that in the short term promoting and implementing ICSs will give the largest improvement in the efficiency of biomass use, whereas on the long term small combustion plants seem to be the best choice for transforming CA's biomass into a clean and sustainable energy carriers, boosting economy and industrial development. Results show that the introduction of ICSs will result in an annual saving in the range of 4-8 Mt of fuelwood (59-113 PJ). Moreover, even when the investment cost of the cooking stoves is considered, ICSs yield economic savings to fuelwood consumers compared to traditional stoves. The total savings during the first year of implementation would be in the range of 19-152 US$/stove. (C) 2016 Elsevier Ltd. All rights reserved.
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| 17. |
- Djerf, Tove, 1989, et al.
(författare)
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Bottom-bed fluid dynamics – Influence on solids entrainment
- 2018
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820. ; 173, s. 112-118
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Tidskriftsartikel (refereegranskat)abstract
- In CFB boilers, the solids concentration along the riser and the external solids circulation are important design parameters. This work provides an experimental investigation on how the solids entrainment from the bottom region of a CFB riser is influenced by the fluidization conditions, in particular if there is a bottom bed or not. Measurements are carried out in a CFB riser with a height of 3 m and 0.45 m 2 in cross section. The solids inventory consists of glass spheres with a mean size of 112 μm, employing fluidization velocities up to 1.4 m/s and riser pressure drops in the range 0.15–1.5 kPa. The vertical distribution of solids concentration is determined through pressure drop measurements along the riser height. The external solids circulation is measured with a valve system in the return leg. The results show that the bottom region conditions govern how operational parameters influence the characteristics of the solids entrainment from the bottom. The vertical extension of the splash zone above the dense bed depends strongly on the dense bed height. In the absence of a dense bed, a bottom region with strong solids back-mixing is established which has similarities with the splash region.
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| 18. |
- Djerf, Tove, 1989, et al.
(författare)
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Bottom-bed fluid dynamics - Influence on solids entrainment
- 2017
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Ingår i: 12th International Conference on Fluidized Bed Technology, CFB 2017. ; 2017, s. 183-190
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Konferensbidrag (refereegranskat)abstract
- In CFB boilers, the solids concentration along the riser and the external solids circulation are important design parameters, mainly in terms of the heat balance but also influencing the risk of wear on heat transfer surfaces. This work investigates experimentally how the amount of solids entrained from the bottom region of a CFB riser is influenced by the fluidization conditions, including the presence or absence of a dense bottom bed. The paper presents first measurements in a new cold lab-scale unit (3 m tall, 0.45 m2in cross section), which is a scale model of a large utility boiler. The solids inventory consists of glass spheres with a mean size of 112 µm. The operational range covers fluidization velocities between 0.1 and 1.4 m/s and riser pressure drops between 0.2 and 1.5 kPa. The vertical distribution of solids concentration is determined through pressure drop measurements between densely spaced pressure taps (15 in total) along the riser height. The external solids circulation is measured with an automatic valve system in the return leg. The results show that the presence or absence of a dense bed govern how operational parameters influence the characteristics of the solids entrainment from the bottom region. The vertical extension of the splash zone above the dense bed depends strongly on the dense bed height. In the absence of a dense bed, a bottom region with strong solids back-mixing is established which has similarities with the splash region.
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| 19. |
- Djerf, Tove, 1989, et al.
(författare)
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Solids circulation in circulating fluidized beds with low riser aspect ratio and varying total solids inventory
- 2016
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Ingår i: Fluidization XV (2016), Quebec, Canada.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents an experimental study with the aim tounderstand the relation between the flow conditions - the riser pressure drop and fluidization velocity - in a CFB riser and the net (external)solids flux (Gs [kg/m2s]), applying a riser geometry and overall flow conditions similar to CFB boilers.The experiments are carried out in a CFB unit operated under ambient conditions. The riser has a cross section of 0.7 m x 0.12 m and a height of 8.5 m, yielding a riser height-to-width aspect ratio of 10.6 (in the wide dimension), similar to that of CFB boilers. The unit is equipped with densely spaced pressure taps providing a fine resolution of the measured vertical pressure profile along the riser and an automatic system to accurately measure Gs. The experiments cover fluidization velocities of 0.3-7 m/s, riser pressure drops of 1.7-10.5 kPa and loopseal fluidization velocities of 0.12-0.54 m/s (secondary air flows are not considered). These ranges correspond to conditions both with and without a dense bottom region.The results show that Gs is determined by the solids concentration at the riser top, which depends riser pressure drop and fluidization velocity, and the backflow effect, which depends on the configuration and flow conditions of the loop seal and the exit region. For operating conditions with a dense bottom bed present, Gs is independent of riser pressure drop, whereas when operating without a dense bed an increase in riser pressure drop yields an increase in Gs.
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| 20. |
- Djerf, Tove, 1989, et al.
(författare)
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Solids circulation in circulating fluidized beds with low riser aspect ratio and varying total solids inventory
- 2017
-
Ingår i: Powder Technology. - : Elsevier BV. - 1873-328X .- 0032-5910. ; 316, s. 670-676
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an experimental study with the aim to understand the relation between the flow conditions - the riser pressure drop and fluidization velocity - in a CFB riser and the net (external) solids flux (Gs [kg/m(2) s]), applying a riser geometry and overall flow conditions similar to CFB boilers. The experiments are carried out in a CFB unit operated under ambient conditions. The riser has a cross section of 0.7 m x 0.12 m and a height of 8.5 m, yielding a riser height-to-width aspect ratio of 10.6 (in the wide dimension), similar to that of CFB boilers. The unit is equipped with densely spaced pressure taps providing a fine resolution of the measured vertical pressure profile along the riser and an automatic system to accurately measure G5. The experiments cover fluidization velocities of 03-7 m/s, riser pressure drops of 1.7-10.5 kPa and loop-seal fluidization velocities of 0.12-0.54 m/s (secondary air flow is not included). These ranges correspond to conditions both with and without a dense bottom region. The results show that G(s) is determined by the solids concentration at the riser top, which in turn depends on riser pressure drop and fluidization velocity, and the backflow effect, which depends on the configuration and flow conditions of the loop seal and the exit region. For operating conditions with a dense bottom bed present, G(s) is independent of riser pressure drop at any fluidization velocity, whereas when operating without a dense bed an increase in riser pressure drop increases G(s).
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