| 1. |
- Ahlström, Johan, et al.
(författare)
-
Sustainable aviation fuels – Options for negative emissions and high carbon efficiency
- 2023
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier Ltd. - 1750-5836 .- 1878-0148. ; 125
-
Tidskriftsartikel (refereegranskat)abstract
- Mitigating the climate impact from aviation remains one of the tougher challenges in adapting society to fulfill stated climate targets. Long-range aviation cannot be electrified for the foreseeable future and the effects of combusting fuel at high altitude increase the climate impact compared to emissions of green-house gasses only, which further limits the range of sustainable fuel alternatives. We investigate seven different pathways for producing aviation biofuels coupled with either bio-energy carbon capture and storage (BECCS), or bio-energy carbon capture and utilization (BECCU). Both options allow for increased efficiency regarding utilization of feedstock carbon. Our analysis uses process-level carbon- and energy balances, with carbon efficiency, climate impact and levelized cost of production (LCOP) as primary performance indicators. The results show that CCS can achieve a negative carbon footprint for four out of the seven pathways, at a lower cost of GHG reduction than the base process option. Conversely, as a consequence of the electricity-intensive CO2 upgrading process, the CCU option shows less encouraging results with higher production costs, carbon footprints and costs of GHG reduction. Overall, pathways with large amounts of vented CO2, e.g., gasification of black liquor or bark, as well as fermentation of forest residues, reach a low GHG reduction cost for the CCS option. These are also pathways with a larger feedstock and corresponding production potential. Our results enable a differentiated comparison of the suitability of various alternatives for BECCS or BECCU in combination with aviation biofuel production. By quantifying the relative strengths and weaknesses of BECCS and BECCU and by highlighting cost, climate and carbon-efficient pathways, these results can be a source of support for both policymakers and the industry. © 2023 The Author(s)
|
|
| 2. |
- Basirat, Farzad, et al.
(författare)
-
Characterization of CO2 self-release during Heletz Residual Trapping Experiment I (RTE I) using a coupled wellbore-reservoir simulator
- 2020
-
Ingår i: International Journal of Greenhouse Gas Control. - : ELSEVIER SCI LTD. - 1750-5836 .- 1878-0148. ; 102
-
Tidskriftsartikel (refereegranskat)abstract
- In order to quantify CO2 residual trapping in situ, two dedicated single-well push-pull experiments have been carried out at the Heletz, Israel pilot CO2 injection site. Field data from some parts of these experiments suggests the important effect of the hydrodynamic behavior in the injection-withdrawal well. In the present work a model capturing the CO2 transport and trapping behavior during Heletz Residual Trapping Experiment I is developed, with a special focus on coupled wellbore-reservoir flow. The simulation is carried out with the numerical simulator T2Well/ECO2N (Pan et al. 2011) which considers the wellbore-reservoir coupling. Of particular interest is to accurately model the period when the well is open to the atmosphere and self-producing CO2 and water in a geyser-like manner. It is also of interest to identify what conditions are causing the oscillating pressure-temperature behavior and the associated periodic gas-liquid releases, as well as to determine the amount of gas lost from the reservoir during this period. The results suggest that the behavior is due to cyclical CO2 exsolution from the aqueous phase along with a reduction of mobility of both CO2 and brine in the near wellbore-reservoir area, the latter being due to a zone of dispersed CO2 bubbles near the wellbore. This behavior could be successfully captured with a new set of relative permeability functions developed earlier for CO2 exsolution in laboratory experiments (Zuo et al., 2013).
|
|
| 3. |
- Dong, Beibei, et al.
(författare)
-
Selecting the approach for dynamic modelling of CO2 capture in biomass/waste fired CHP plants
- 2023
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier Ltd. - 1750-5836 .- 1878-0148. ; 130
-
Tidskriftsartikel (refereegranskat)abstract
- Integrating CO2 capture with biomass/waste fired combined heat and power (CHP) plants is a promising method to achieve negative emissions. However, the use of versatile biomass/waste and the dynamic operation of CHP plants result in bigger fluctuations in the properties of flue gas (FG), e.g. CO2 concentration (CO2vol%) and flowrates, and the heat that can be used for CO2 capture, when comparing with coal fired power plants. To address such a challenge, dynamic modelling is essential to accurately estimate the amount of captured CO2 and optimize the operation of CO2 capture. This paper compares three dynamic approaches commonly used in literature, namely using the ideal static model (IST) and using dynamic models without control (Dw/oC) and with control (DwC), for MEA based chemical absorption CO2 capture. The performance of approaches is assessed under the variations of key factors, including the flowrate and CO2vol% of FG, and the available heat for CO2 capture. Simulation results show clear differences. For example, when the CO2vol% drops from 15.7 % to 9.7 % (about 38 %) within 4 hours, DwC gives the highest amount of captured CO2, which is 7.3 % and 22.3 % higher than IST and Dw/oC, respectively. It is also found that the time step size has a clear impact on the CO2 capture amount, especially for DwC. Based on the results, suggestions are also provided regarding the selection of dynamic modelling approaches for different purposes of simulations.
|
|
| 4. |
- Gustafsson, Kåre, et al.
(författare)
-
BECCS with combined heat and power : Assessing the energy penalty
- 2021
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 108
-
Tidskriftsartikel (refereegranskat)abstract
- Bio-energy with carbon capture and storage (BECCS) is widely recognised as an important carbon dioxide removal technology. Nevertheless, BECCS has mostly failed to move beyond small-scale demonstration units. One main factor is the energy penalty incurred on power plants. In previous studies, this penalty has been determined to be 37.2 %?48.6 % for the amine capture technology. The aim of this study is to quantify the energy penalty for adding the hot potassium carbonate (HPC) capture technology to a biomass-fired combined heat and power (CHP) plant, connected to a district heating system. In this context, the energy driving the capture process is partly recovered as useful district heating. Therefore, a modified energy penalty is proposed, with the inclusion of recovered heat. This inclusion is especially meaningful if the heat has a substantial monetary value. The BECCS system is examined using thermodynamic analysis, coupled with modelling of the capture process in Aspen PlusTM. Model validation is performed with data from a BECCS test facility. The results of this study show that the modified energy penalty is in the range of 2%?4%. These findings could potentially increase the attractiveness of BECCS as a climate abatement option in a district heating CHP setting.
|
|
| 5. |
- Joodaki, Saba, et al.
(författare)
-
Model analysis of CO2 residual trapping from single-well push pull test based on hydraulic withdrawal tests : Heletz, residual trapping experiment I
- 2020
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 97
-
Tidskriftsartikel (refereegranskat)abstract
- Residual or capillary trapping is one of the key trapping mechanisms for geological storage of CO2. Yet, very few studies so far have attempted to estimate the residual trapping and the related characteristic parameter, residual saturation, in situ. At Heletz, a pilot CO2 injection site in Israel a single-well push-pull experiment to estimate residual gas saturation in situ was carried out during autumn 2016. The main characterization method was hydraulic withdrawal tests. The residually trapped zone was also created by means of fluid withdrawal, by first injecting CO2 and then withdrawing fluids leaving behind the immobile residual CO2. This paper presents the first model interpretation of the experimental results. Numerical modeling with TOUGH2/ECO2N was carried out to model the entire test sequence, the focus being in matching the collected pressure, temperature and flow data as well as observations of gas content in the borehole. The experimental results could be well fitted with the model that also is in agreement with previously collected petro-physical data. The results indicate a somewhat lower residual gas saturation than that measured in the laboratory, the estimated maximum residual saturation from the field experiment being 10% and the corresponding value from the core 20%. The results also indicate that most of the CO2 entered the upper reservoir layer, thus actually giving an estimate of the effective residual trapping in that layer. Overall, pressure response gave a clear signal and was an effective method in getting an estimate of the effective residual trapping in the interval tested.
|
|
| 6. |
- Joodaki, Saba, et al.
(författare)
-
Model analysis of CO2 residual trapping from single-well push pull test - Heletz, Residual Trapping Experiment II
- 2020
-
Ingår i: International Journal of Greenhouse Gas Control. - : ELSEVIER SCI LTD. - 1750-5836 .- 1878-0148. ; 101
-
Tidskriftsartikel (refereegranskat)abstract
- Residual or capillary trapping is one of the key trapping mechanisms for CO2 geological storage. At the Heletz, Israel, pilot injection site, two dedicated field experiments have been carried out to characterize it in-situ. This paper presents the model analyses of the second of these tests, the Residual Trapping Experiment II (RTE II). In the experiment hydraulic, tracer and thermal tests before and after the generation of the residually trapped zone are used to quantify residual saturation. The creation of the residually trapped zone is based on injection of CO2-saturated-water following injection of free-phase supercritical CO2. For the modeling, both a radial-symmetric model with homogeneous layer properties and 3D model with stochastically heterogeneous properties were used. Extensive parameter sensitivity studies were carried out and various well-geometry related fluid injection/withdrawal scenarios were considered. In terms of the best estimate for the maximum residual saturation, this experiment, like the previous RTE I experiment, gave the best agreement with a residual gas saturation of 0.1, this value being somewhat lower than the core-measured value of 0.2. Overall, the pressure response provided a very robust signal enabling to distinguish different values of residual saturation as well as the extent of sections where gas blocking for water flow could have occurred. Analysis of the tracer data indicated the presence of phenomena such as gas-blocking water flow, the importance of multi-layer and channelized flow and transport, and the importance of taking into account the processes in the actual injection/production well also.
|
|
| 7. |
- Lefvert, Adrian, et al.
(författare)
-
Smarter ways to capture carbon dioxide-exploring alternatives for small to medium-scale carbon capture in Kraft pulp mills
- 2023
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836 .- 1878-0148. ; 127
-
Tidskriftsartikel (refereegranskat)abstract
- Carbon capture from the calcination process in Kraft pulp mills, also known as sulphate pulp mills, has potential as a part of carbon capture and storage (CCS) infrastructure deployment. Growing concern of climate change is increasing the interest for so-called negative emission technologies (NETs), and large emission points have great potential. However, among other factors, lack of financial incentives, trade-off with investments in existing products, and the necessity of large infrastructure that stretch across country borders, constrain deployment. This study investigates two concepts for carbon capture in combination with lime kilns in Kraft pulp mills: oxyfuel combustion and electric arc plasma calcination. The results from the modelling of six configurations show that carbon capture from the calcination process with these technologies can be made with comparatively low additional energy demand. Sulphate pulp production from Kraft pulp mills, which use lime kilns, is increasing in Europe and in the world. Therefore, there is large potential for capture of CO2 from these alternative calcination technologies, both as a first step towards and as a part of a large-scale deployment of CCS and bioenergy with CCS (BECCS).
|
|
| 8. |
- Martinez-Landa, Lurdes, et al.
(författare)
-
A methodology for the interpretation of aquifer tests : Application to CO2 residual trapping experiments at the Heletz site
- 2021
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier. - 1750-5836 .- 1878-0148. ; 112
-
Tidskriftsartikel (refereegranskat)abstract
- Estimation of trapped CO2 is essential for assessing the potential of a site for geological carbon storage. In situ residual trapping can be obtained through Residual Trapping Experiments (RTE). RTE experiments consist in performing characterization tests e.g. hydraulic, thermal and tracer tests before and after creating the residually trapped zone of CO2 and estimating residual saturation from the differences between the two tests. We introduce a methodology for interpreting residual drawdowns from hydraulic tests, and specifically those performed before and after the creation of the residually trapped zone. Martinez-Landa et al. (2013) demonstrated that the reduction of hydraulic conductivity and the increase in storativity within the trapped CO2 zone can produce early time differences that are significant. However, our interpretation is hindered by the fact that accurate measurement of early time (a few minutes) response is difficult because the large inertia of the system prevents us from rapidly establishing a controlled constant flow-rate. This is particularly true for the RTE test at Heletz, where water withdrawal during the hydraulic tests had to be performed by air-lift. To resolve this difficulty, we use the proposed methodology which avoids instabilities derived from changes in flow rates. Our approach consists of four steps: (1) filtering of natural trends in heads to ensure good definition of drawdowns; (2) transformation of residual drawdowns into constant pumping test drawdowns, by using the Agarwal or other methods, while accounting for flow rate variations during the pumping phase; (3) computation of smooth log-derivatives to prepare diagnostic plots to aid in conceptual model identification; and (4) quantitative interpretation. The application of our approach to the Heletz RTE experiment gave rise to diagnostic plots consistent with theoretical expectations and a residual CO2 saturation of about 10%.
|
|
| 9. |
- Mei, Daofeng, 1986, et al.
(författare)
-
Investigation of LD-slag as oxygen carrier for CLC in a 10 kW unit using high-volatile biomasses
- 2023
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier Ltd. - 1750-5836 .- 1878-0148. ; 127
-
Tidskriftsartikel (refereegranskat)abstract
- A steel slag from the Linz-Donawitz process, called LD-slag, having significant calcium and iron-fractions, was investigated as an oxygen carrier in a recently developed 10 kWth chemical-looping combustor with three high-volatile biomass fuels. In order to improve operability, the LD-slag was found to require heat-treatment at high temperatures before being used in the unit. In total, operation with the biomasses was conducted for more than 26 h at temperatures of 870–980 °C. The fuel thermal power was in the range of 3.4–10 kWth. The operation involved chemical looping combustion (CLC), chemical looping gasification (CLG) and oxygen carrier aided combustion (OCAC). Around 12 h was in CLC operation, 13.3 h was conducted in CLG-conditions, while the remaining 0.7 h was OCAC. Here, the results obtained during the CLC part of the campaign is reported. Increased temperature in the fuel reactor and higher airflows to the air reactor both lead to better combustion performance. Steam concentration in the fuel reactor has little effect on the performance. The LD-slag showed higher oxygen demand (31.0%) than that with ilmenite (21.5%) and a manganese ore (19.5%) with the same fuel and normal solids circulation. However, with the LD-slag, there is possibility to achieve a lower oxygen demand (15.2%) with high solids circulation. © 2023 The Author(s)
|
|
| 10. |
- Moghadasi, Ramin, et al.
(författare)
-
Role of critical gas saturation in the interpretation of a field scale CO2 injection experiment
- 2022
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier. - 1750-5836 .- 1878-0148. ; 115
-
Tidskriftsartikel (refereegranskat)abstract
- Residual trapping of CO2, typically quantified by residual gas saturation (Sgr), is one of the main trapping mechanisms in geological CO2 storage (GCS). An important additional characteristic parameter is critical gas saturation (Sgc). Sgc determines at what saturation the trapped gas remobilizes again if gas saturation increases due to exsolution from the aqueous phase, rather than from further gas injection. In the present study, a pilot-scale CO2 injection experiment carried out at Heletz, Israel, in 2017, is interpreted by taking critical saturation into account. With regards to this experiment, the delayed second arrival peak of the partitioning tracer could not be captured by means of physical models. In this work, the hysteretic relative permeability functions were modified to account for Sgc. The results showed that accounting for the effect of Sgc during the secondary drainage indeed captured the observed delayed peak. The difference between the values of Sgr and Sgc, influenced both the time and peak height of the tracer arrival. To our knowledge this is first time that critical gas saturation has been considered in field scale analyses related to GCS. Accounting for Sgc is relevant where gas saturation during secondary drainage increases due to gas phase expansion or exsolution from the aqueous phase. This will happen in situations where pressure depletion occurs, e.g. due to gas leakage from fracture zones or wells or possibly because of pressure management activities. The findings also have implications for other applications such as underground gas storage as well as for geothermal reservoir management.
|
|
