International Journal of Greenhouse Gas Control最新文献

Reducing greenhouse gas emissions in the shipping sector is a challenging task. While renewable fuels stand out as the most promising long-term solution, their near- and mid-term viability is hampered by limited availability and high costs. An alternative approach is onboard carbon capture, which can reduce emissions from new ships as well as retrofitted vessels. This paper examines the techno-economic potential of oxyfuel combustion based carbon capture on ships. The oxyfuel concept uses an oxygen-rich atmosphere in the combustion process, resulting in a mixture of carbon dioxide and water. After the condensation of water, the carbon dioxide rich gas can be directly stored on board. Various onboard oxygen supply concepts are investigated, including different technologies for onboard air separation and liquid oxygen bunkering. Influences on the ship energy system are studied by system simulation of a deep-sea container vessel. Benchmarked against a technologically mature post-combustion carbon capture system, the results show that the oxyfuel concepts have limited competitiveness because of reduced engine efficiencies and high energy demands for onboard oxygen supply. Avoiding onboard oxygen supply by using liquefied oxygen as a byproduct from onshore electrolysis increases energy efficiency and the competitiveness of oxyfuel combustion but requires additional storage space. Sensitivity analyses highlight that the engine combustion concept and engine efficiency are the most critical influences on the techno-economic performance.

There has been an increased interest in the use of solid sorbents for CO₂ capture from flue gases to reduce emissions from fossil energy. This work uses a simple Carnot engine-like model to compare the energy requirements for a CO₂ capture process using a solid adsorbent in a circulating fluidized bed with its minimal thermodynamic needs and with the performance of a conventional liquid solvent process. The energy requirements for CO₂ capture using thermal swing separation sorption are dominated by the standard Gibbs free energy of separation from the sorbent ($\Delta g_{0,sep}$), the sensible heat needed to reach the desorption temperature, and loading optimization to avoid thermodynamic pinching effects. The $\Delta g_{0,sep}$ is an invariant of the system, so only its value at reference conditions is required and it is independent of the desorption temperature or the heat of evaporation of a liquid solvent. A baseline is established using the $\Delta g_{0,sep}$ as well as the equivalent work for a well-established amine process. In all cases the energy requirements are found to be well above the minimum thermodynamic values and those of conventional liquid absorption. Higher-capacity solid sorbents and challenging improvements on heat recovery will be needed to close the gap.

This paper studies the effects of exposure to CO₂-rich brine on sandstones and marls considered potential deep storage reservoir and seal in the Ebro Basin, Spain.

The experiment was conducted in a reactor under conditions of deep saline formations (pressure 8 MPa, temperature 313 K, exposure time 30 days, and CO₂-supersaturated seawater ≈0.80 Mol). Both exposed and non-exposed samples were characterised by means of Optical Microscopy, Scanning Electronic Microscopy, X-ray Diffraction and Digital Image Analysis. Furthermore, powdered samples were analysed chemically trough X-ray Fluorescence, and brine samples were subjected to chemical analysis.

The petrographic study of adjacent sandstone samples before and after the exposure to CO₂-rich brine indicates an increase in porosity (≈3 %). These changes in pore structure are the result of mineral dissolution (e.g., siliceous cement) and intergranular matrix detachment and its partial removal from the rock sample, representing the initial effects induced by the CO₂-rich brine. The chemical analysis of the brine reveals an increase in Ca²⁺ and SiO₂ composition (29 % and 6670 %, respectively). After marl exposure, the brine also exhibited increased Ca²⁺and SiO₂ content (95 % and 11,250 %, respectively), indicating the prevalence of dissolution processes.

These results suggest that in environments where CO₂ enriches the brine the mixture primarily induces localized chemical adjustments in the rocks (evidenced by dissolutions in the brine). The proposed methodology can be adapted for similar experimental batch tests in other storage structures.

The petrochemical industry has a significant demand for high-purity hydrogen. It primarily obtained from the H₂ purification unit by using pressure swing adsorption (PSA) technology to recover H₂ from medium-temperature shifting gas (MTSG). The the coupled wet CO₂ separation-PSA process was introduced in this work, aiming to capture CO₂ from MTSG while simultaneously increasing the H₂ recovery rate. To enhance the desorption pressure of CO₂ separation unit in the coupled process to facilitate the storage or utilization of the captured CO₂, firstly, a rigorous thermodynamic study was carried out to provide a theoretical basis for the development of an improved CO₂ solvent. Subsequently, a pilot-scale test was executed to validate the theoretical findings. Finally, the patented coupled process was implemented at an industrial scale for the first time. The results showed that the capacity of PSA unit for H₂ purification increased from 6800 to 12,000 tons per year and the H₂ recovery rate increased from 84.6 % to 93.6 %; the CO₂ desorption pressure increased from about 0.03 MPa (traditional Benfield process) to 0.15 MPa, which reduced the energy consumption of CO₂ compression, and the total average annual economic benefits increased by US $ 15.55 million.

We evaluate if electromagnetic (EM) geophysical methods for monitoring geologic carbon storage (GCS) efforts at the Wyoming CarbonSAFE project adjacent to the Dry Fork Station power plant near Gillette, Wyoming. This first involved acquiring both electric and magnetic fields at eleven different locations ranging in distance from immediately adjacent to 4 km from the plant. Passive EM measurements were made to provide spectral EM noise measurements generated by electricity production at the plant and to determine if useful magnetotelluric (MT) data can be successfully collected in the region. The processed data indicate that useful MT data can be collected as long as the site is located more than 2km away from the power plant as well as active roads and rail lines. Controlled source EM data were collected using three different source configurations, two of which connected to steel casings used to complete the injection wells. Comparing the EM noise measurements to the CSEM data show measurable electric and magnetic field signals at all sites. Next a series of three-dimensional (3D) numerical models were built that simulate resistivity changes caused by the proposed CO₂ injection at depths ranging from 2.4 to 3.0km. These models were used to simulate various EM measurement configurations. The modeling shows that casing-source CSEM monitoring can provide sensitivity to the injected CO₂ if source electrodes are connected to the bottom of one or both of the injection wells.

Over 20 million tons of CO₂‌ have been injected into the sandy Utsira formation of the Sleipner field in the North Sea basin. The thin layering of sands, CO₂-saturated sands, and intra-formation thin shales cause interference effects in the seismic response of the monitor surveys. Initial analysis of the amplitude change suggests over 60 % change in the relative acoustic impedance of the reservoir between the 1996 and 2010 surveys. This study follows a multi-stage inversion scheme applied to time-lapse seismic monitoring of the Sleipner field. At each stage, the errors and uncertainties caused by noise and tuning are deeply analyzed. Time-shift estimation from seismic data shows spurious features caused by tuning, specifically using the window-based methods. The time-strain inversion builds a low-frequency initial model for the subsequent model-based inversion but is contaminated by remnants of noise and interference. The synthetic wedge modelling and analysis provides the origins and severity of the tuning error in time-shift and time-strain estimations at the Sleipner field. The model-based inversion removes noise and injects high-frequency components into the results, improving the outcome of time-strain inversion. However, it fails to fully eliminate the tuning imprints and leaves strong traces of error on the results. Afterward, the time-lapse Bayesian seismic inversion slightly adjusts the outcome and shows how deep the influence of interference effect on the time-lapse inversion is. In addition, the complementary discussion on rock physical models in estimating the saturation changes highlights how the tuning error can lead to flawed quantitative interpretation.

Future projections of oil and gas demand suggest that some production will remain necessary. Although attention often focuses on CO₂ emissions from the combustion of their products, oil and gas production is also a relevant global emission source of both CO₂ and CH₄. Hence, understanding the carbon performance of upstream activities in producing nations is vital for distinguishing producers in a climate-pressured global market. This work explores climate strategies for the oil and gas upstream sector, using Brazil as a case study. The sector´s emissions profile is evaluated under distinct national climate scenarios. The analysis employs BLUES, a national Integrated Assessment Model (IAM), to access production volumes, mitigation measures applicable to the sector, and carbon dioxide removal potentials within the country to eventually offset the sector's remaining emissions. Results indicate sustained oil and gas production over the evaluated horizon (2020–2050) without compromising national climate goals, yet the sector's future emissions trajectory does not align with decarbonization targets pursued by more ambitious oil-producing nations and industry players. Despite sectoral mitigation measures indicated by the model, considerable emissions remain until 2050. Conversely, the country offers ample offsetting opportunities with potential synergies for the sector, especially through BECCS. Furthermore, the acceptability of offsets is discussed.

Limiting global warming to a 2 °C rise may require large-scale deployment of carbon capture and storage (CCS). Due to the key role CCS plays in integrated assessment models of climate change mitigation, it is important that fundamental physical constraints are accounted for. We produce a global estimate of CO₂ storage resource that accounts for pressure-limits within basin-scale reservoir systems. We use a dynamic physics model of reservoir pressurisation that is sufficiently simple to be incorporated into energy systems models. Our estimates address regionally inconsistent methodologies and the general lack of consideration for pressure limitations in global storage resource estimates. We estimate a maximum pressure-limited resource base and explore scenarios with different injection patterns, and scenarios where the extent of CCS deployment is limited by the history of regional hydrocarbon exploration and the readiness of countries for deployment. The maximum pressure-limited global storage achievable after thirty years of injection is 3640GtCO₂ (121GtCO₂yr^-1), increasing to 5630GtCO₂ (70 GtCO₂yr^-1) at the end of the century. These represent an update to volumetric-based estimates that suggest in excess of 10,000Gt of storage resource available. When CCS deployment is limited to the top ten countries ranked by the GCCSI Storage Readiness Index, our maximum storage estimate decreases to 780GtCO₂ (26GtCO₂yr^-1) at the mid-century and 1177GtCO₂ (15GtCO₂yr^-1) at the end of the century. These latter results fall within the range of projected deployment by the IPCC and IEA and suggest that reservoir pressurisation will limit CCS deployment if development does not rapidly expand beyond the current implementation.

Carbon capture and storage will be necessary for some industries to reach carbon neutrality. One of the main associated challenges is the design of the network linking the CO₂ sources to the storage sites. Establishing a CO₂ network can be impacted by many uncertainties such as CO₂ amounts, pipeline routes and the locations of emitters and carbon sinks. We present a framework to investigate different scenarios of a future CO₂ network in Germany. The analyses compare the routes and associated costs of different scenarios. The developed model uses several geospatial datasets and an optimization scheme to yield realistic and cost-efficient outcomes. Parameters such as population density and existing infrastructure are integrated to calculate potential routes, which are then used as an input for the developed heuristic model to determine the optimum network. The derived framework is flexible and can be used for investigating other scenarios, regions and settings. The results show that the different scenarios have a profound impact on the optimal layout and costs. The investment costs of the investigated scenarios range between 1.3 and 3 billion EUR. The outcomes are important for academia, industry and policymaking for the ongoing discussions regarding the development of carbon infrastructure.