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To meet a 2 degree Paris target, Carbon Capture and Storage technologies are required.
In ten seconds? To combat climate change, main policy efforts should be directed towards emission reductions, but we also need strategies with negative emission technologies: mineral carbonation, land management, bioenergy & direct air capture with reliable storage in special reservoirs, such as underground formations.
Researchers have reviewed available Carbon Capture & Storage methods and estimated that 35 gigatons (GT) of CO2 can potentially be removed from the atmosphere every year, which is almost equal to the current annual emissions from fuel combustion of 36 GT. The main problem is the price of removal.
In search for a cheap and reliable artificial materials to capture CO2, such as porous organic polymers, researchers have recently invented a very light hexagonal-boron nitride foam that soaks up more than three times its weight in CO2, and this foam is reusable! (read more here)
Researchers also suggest using living organisms to capture CO2. Algae grown in bioreactors sequester CO2 in flue gas. Then this algal biomass can be used as a food protein source bringing positive revenues (read the science here).
In nature, atmospheric CO2 is captured by soil, forests and oceans. Researchers have discovered a tiny transport vehicle for carbon: zooplankton copepods. They eat phytoplankton rich in carbon on the ocean surface and then migrate to deep ocean basins where this carbon is emitted, but remains trapped and does not enter the atmosphere (read more here).
Carbon transportation and storage carry risks such as ground deformation, earthquakes and CO2 leakages. Leakage monitoring is very important. Researchers have recently suggested a low-cost method to detect the CO2 leaks: unlike the fossil derived CO2, atmospheric CO2 always contains some radiocarbon, and this difference can be measured, such as if the atmospheric CO2 had marking.
Abstract: Basalt formations could enable secure long-term carbon storage by trapping injected CO2 as stable carbonates. Here, a predictive modeling framework was designed to evaluate the roles of transport limitations and mineral spatial distributions on mineral dissolution and carbonation reactions in fractured basalts exposed to CO2-acidified fluids. Reactive transport models were developed in CrunchTope based on data from high-temperature, high-pressure flow-through experiments. Models isolating the effect of transport compared nine flow conditions under the same mineralogy. Heterogeneities were incorporated by segmenting an actual reacted basalt sample, and these results were compared to equivalent flow conditions through randomly generated mineral distributions with the same bulk composition. While pure advective flow with shorter retention times promotes rapid initial carbonation, pure diffusion sustains mineral reactions for longer time frames and generates greater net carbonate volumes. For the same transport conditions and bulk composition, exact mineral spatial distributions do not impact the amount of carbonation but could determine the location by controlling local solution saturation with respect to secondary carbonates. In combination, the results indicate that bulk mineralogy will be more significant than small-scale heterogeneities in controlling the rate and extent of CO2 mineralization, which will likely occur in diffusive zones adjacent to flow paths or in dead-end fractures.
Pub.: 13 Jul '17, Pinned: 30 Aug '17
Abstract: To limit global warming to <2 °C we must reduce the net amount of CO2 we release into the atmosphere, either by producing less CO2 (conventional mitigation) or by capturing more CO2 (negative emissions). Here, using state-of-the-art carbon-climate models, we quantify the trade-off between these two options in RCP2.6: an Intergovernmental Panel on Climate Change scenario likely to limit global warming below 2 °C. In our best-case illustrative assumption of conventional mitigation, negative emissions of 0.5-3 Gt C (gigatonnes of carbon) per year and storage capacity of 50-250 Gt C are required. In our worst case, those requirements are 7-11 Gt C per year and 1,000-1,600 Gt C, respectively. Because these figures have not been shown to be feasible, we conclude that development of negative emission technologies should be accelerated, but also that conventional mitigation must remain a substantial part of any climate policy aiming at the 2-°C target.
Pub.: 04 Aug '15, Pinned: 29 Aug '17
Abstract: Estimates of carbon flux to the deep oceans are essential for our understanding of global carbon budgets. Sinking of detrital material ("biological pump") is usually thought to be the main biological component of this flux. Here, we identify an additional biological mechanism, the seasonal "lipid pump," which is highly efficient at sequestering carbon into the deep ocean. It involves the vertical transport and metabolism of carbon rich lipids by overwintering zooplankton. We show that one species, the copepod Calanus finmarchicus overwintering in the North Atlantic, sequesters an amount of carbon equivalent to the sinking flux of detrital material. The efficiency of the lipid pump derives from a near-complete decoupling between nutrient and carbon cycling—a "lipid shunt," and its direct transport of carbon through the mesopelagic zone to below the permanent thermocline with very little attenuation. Inclusion of the lipid pump almost doubles the previous estimates of deep-ocean carbon sequestration by biological processes in the North Atlantic.
Pub.: 05 Sep '15, Pinned: 21 Aug '17
Abstract: One of the main ways that continued use of coal is justified, and compensated for, is through fantasies of technology. This paper explores the politics of 'Carbon Capture and Storage' (CCS) technologies in Australia. These technologies involve capturing CO2 emissions, usually to store them 'safely' underground in a process called 'geo-sequestration'. In Australia the idea of 'clean coal' has been heavily promoted, and is a major part of CO2 emissions reduction plans, despite the technological difficulties, the lack of large scale working prototypes, the lack of coal company investment in such research, and the current difficulties in detecting leaks. This paper investigates the ways that the politics of 'clean coal' have functioned as psycho-social defence mechanisms, to prolong coal usage, assuage political discomfort and anxiety, and increase the systemic disturbance produced by coal power.
Pub.: 07 Jun '16, Pinned: 21 Aug '17
Abstract: Publication date: October 2016 Source:International Journal of Greenhouse Gas Control, Volume 53 Author(s): Daiju Narita, Gernot Klepper Carbon dioxide capture and storage (CCS) is considered to be an important option for reducing carbon dioxide (CO2) emissions. However, its economic viability remains a question, especially if the risk of leakage in the storage site is taken into account. We use a real options approach for assessing the impact of uncertainty on the timing and the profitability of CO2 storage projects. We model an investment decision for a storage site under uncertainty about CO2 leaking from the storage site, about the development of carbon prices, and about the cost of investment. The numerical model results show that investment under these uncertainties requires a much larger price for carbon credits for storage than an investment plan ignoring uncertainty would suggest. We also show under reasonable parameter assumptions that the risk for investing in CO2 storage is dominated by the uncertain development of carbon prices, whereas the risk of carbon leakage has little influence on the investment decision.
Pub.: 04 Aug '16, Pinned: 21 Aug '17
Abstract: Carbon dioxide capture and storage (CCS), involving the injection of CO2 into the sub-seabed, is being promoted worldwide as a feasible option for reducing the anthropogenic CO2 emissions into the atmosphere. However, the effects on the marine ecosystems of potential CO2 leakages originating from these storage sites have only recently received scientific attention, and little information is available on the possible impacts of the resulting CO2-enriched seawater plumes on the surrounding benthic ecosystem. In the present study, we conducted a 20-weeks mesocosm experiment exposing coastal sediments to CO2-enriched seawater (at 5000 or 20,000 ppm), to test the effects on the microbial enzymatic activities responsible for the decomposition and turnover of the sedimentary organic matter in surface sediments down to 15 cm depth. Our results indicate that the exposure to high-CO2 concentrations reduced significantly the enzymatic activities in the top 5 cm of sediments, but had no effects on subsurface sediment horizons (from 5 to 15 cm depth). In the surface sediments, both 5000 and 20,000 ppm CO2 treatments determined a progressive decrease over time in the protein degradation (up to 80%). Conversely, the degradation rates of carbohydrates and organic phosphorous remained unaltered in the first 2 weeks, but decreased significantly (up to 50%) in the longer term when exposed at 20,000 ppm of CO2. Such effects were associated with a significant change in the composition of the biopolymeric carbon (due to the accumulation of proteins over time in sediments exposed to high-pCO2 treatments), and a significant decrease (∼20–50% at 5000 and 20,000 ppm respectively) in nitrogen regeneration. We conclude that in areas immediately surrounding an active and long-lasting leak of CO2 from CCS reservoirs, organic matter cycling would be significantly impacted in the surface sediment layers. The evidence of negligible impacts on the deeper sediments should be considered with caution and further investigated simulating the intrusion of CO2 from a subsurface source, as occurring during real CO2 leakages from CCS sites.
Pub.: 26 Oct '16, Pinned: 21 Aug '17
Abstract: Carbon dioxide capture and storage (CCS) is regarded as a powerful technology in mitigating the impacts of climate change and is considered as interim solution until other sustainable energy technologies can be used on a broader scale. Despite the fact that well conducted geological risk analyses exists, a major toxicological risk assessment including all components of the process is missing. Therefore, a literature study was undertaken with its focus on potential toxicological risks. These could appear in all parts of the CCS chain: in the capture process when chemicals are used for scrubbing, during transportation in case of accidents, and during geological storage when a leakage of CO2 or brine occurs. Toxicological hazards of special concern emerge not from CO2, but degradation products of scrubbing chemicals (nitrosamines and nitramines) or H2S-co-transportation. Additionally, contamination of potable aquifers due to mobilisation of hazardous trace elements, such as arsenic, nickel, and lead could become relevant in case of a leakage. Overall, to achieve further safety for the implementation of CCS as a mitigation technology, investigations in acute CO2-toxicity (with derivation of mass-intoxications threshold values), acute emergency management, and contaminants should be prime objectives for future CCS risk assessment research.
Pub.: 18 Nov '16, Pinned: 21 Aug '17
Abstract: Publication date: January 2017 Source:International Journal of Greenhouse Gas Control, Volume 56 Author(s): J.C. Turnbull, E.D. Keller, M.W. Norris, R.M. Wiltshire We outline the methodology for detection of carbon dioxide (CO2) leaks to the atmosphere from carbon capture and storage (CCS) using measurements of radiocarbon in CO2. The radiocarbon method can unambiguously identify recently added fossil-derived CO2 such as CCS leaks due to the very large isotopic difference between radiocarbon-free fossil derived CO2 and natural CO2 sources with ambient radiocarbon levels. The detection threshold of 1ppm of fossil-derived CO2 is comparable to other proposed atmospheric detection methods for CCS leakage. We demonstrate that this method will allow detection of a 1000 ton C yr−1 leak 200–300m from the source during the day and more than 600m away at night. Using time-integrated sampling techniques, long time periods can be covered with few measurements, making the method feasible with existing laboratory-based radiocarbon measurement methods We examine the method using previously published observations and new model simulations for a case study in Taranaki, New Zealand. Plant material faithfully records the radiocarbon content of assimilated CO2 and we show that short-lived grass leaves and cellulose from tree rings provide effective time-integrated collection methods, allowing dense spatial sampling at low cost. A CO2 absorption sampler allows collection at controlled times, including nighttime, and gives similar results.
Pub.: 29 Nov '16, Pinned: 21 Aug '17
Abstract: Direct air capture, the chemical removal of CO2 directly from the atmosphere, may play a role in mitigating future climate risk or form the basis of a sustainable transportation infrastructure. The current discussion is centered on the estimated cost of the technology and its link to "overshoot" trajectories, where atmospheric CO2 levels are actively reduced later in the century. The American Physical Society (APS) published a report, later updated, estimating the cost of a one million tonne CO2 per year air capture facility constructed today that highlights several fundamental concepts of chemical air capture. These fundamentals are viewed through the lens of a chemical process that cycles between removing CO2 from the air and releasing the absorbed CO2 in concentrated form. This work builds on the APS report to investigate the effect of modifications to the air capture system based on suggestions in the report and subsequent publications. The work shows that reduced carbon electricity and plastic packing materials (for the contactor) may have significant effects on the overall price, reducing the APS estimate from $610 to $309/tCO2 avoided. Such a reduction does not challenge postcombustion capture from point sources, estimated at $80/tCO2, but does make air capture a feasible alternative for the transportation sector and a potential negative emissions technology. Furthermore, air capture represents atmospheric reductions rather than simply avoided emissions.
Pub.: 11 Sep '14, Pinned: 21 Aug '17
Abstract: Carbon dioxide is one of the most important greenhouse gas, which concentration increase in the atmosphere is associated to climate change and global warming. Besides CO2 capture in large emission point sources, the capture of this pollutant from atmosphere may be required due to significant contribution of diffuse sources. The technologies that remove CO2 from atmosphere (creating a negative balance of CO2) are called negative emission technologies. Bioenergy with Carbon Capture and Storage may play an important role for CO2 mitigation. It represents the combination of bioenergy production and carbon capture and storage, keeping carbon dioxide in geological reservoirs. Algae have a high potential as the source of biomass, as they present high photosynthetic efficiencies and high biomass yields. Their biomass has a wide range of applications, which can improve the economic viability of the process. Thus, this paper aims to assess the atmospheric CO2 capture by algal cultures.
Pub.: 14 Mar '16, Pinned: 21 Aug '17
Abstract: Although CO2 geological storage has been recognized as an effective strategy to lower carbon emissions directly, there are no suitable guidelines for safety risk assessment of CO2 geological storage projects in deep saline aquifers in China and elsewhere. When CO2 is injected into deep saline aquifers, stratigraphic and structural trapping is the major basic mechanism controlling CO2 storage capacity and migration in reservoirs. Therefore, a safety risk assessment method is proposed in this paper using perspectives from hydrogeological and environmental geology. The uncertainties and risks consist of CO2 leakage, ground deformation, and induced earthquakes. Identifying and assessing potential risks are the first and most important step in the process of risk assessment. Based on the identification of risks of CO2 geological storage projects, we built an elementary risk evaluation index system in an analytic hierarchy process framework. Meanwhile, the possibility of occurrence and damage to the environment and public caused by CO2 leakage, ground deformation, and induced earthquakes was analyzed in detail, and current risk criteria were also summarized. Furthermore, using the Shenhua CO2 Capture and Storage Demonstration Project as a case study, we performed a risk identification and evaluation by using qualitative or semi-quantitative methods in sequence, as well as developing the related preliminary risk management measures. This method and case study for short-term safety risk assessment could provide a guideline for site selection, injection design, and monitoring of CO2 geological storage projects in deep saline aquifers.
Pub.: 21 Dec '14, Pinned: 21 Aug '17
Abstract: Carbon dioxide (CO2) capture and storage (CCS) is considered widely as one of promising options for CO2 emissions reduction, especially for those countries with coal-dominant energy mix like China. Injecting and storing a huge volume of CO2 in deep formations are likely to cause a series of geomechanical issues, including ground surface uplift, damage of caprock integrity, and fault reactivation. The Shenhua CCS demonstration project in Ordos Basin, China, is the first and the largest full-chain saline aquifer storage project of CO2 in Asia. The injection started in 2010 and ended in 2015, during which totally 0.3 million tonnes (Mt) CO2 was injected. The project is unique in which CO2 was injected into 18 sandstone formations simultaneously and the overlying coal seams will be mined after the injection stopped in 2015. Hence, intense geomechanical studies and monitoring works have been conducted in recent years, including possible damage resulting from the temperature difference between injected CO2 and formations, injection induced stress and deformation change, potential failure mode and safety factor, interaction between coal mining and CO2 geological storage, determination of injection pressure limit, and surface monitoring by the interferometric synthetic aperture radar (InSAR) technology. In this paper, we first described the background and its geological conditions of the Shenhua CCS demonstration project. Then, we gave an introduction to the coupled thermo-hydro-mechano-chemical (THMC) processes in CO2 geological storage, and mapped the key geomechanical issues into the THMC processes accordingly. Next, we proposed a generalized geomechanical research flowchart for CO2 geological storage projects. After that, we addressed and discussed some typical geomechanical issues, including design of injection pressure limit, CO2 injection induced near-field damage, and interaction between CO2 geological storage and coal mining, in the Shenhua CCS demonstration project. Finally, we concluded some insights to this CCS project.
Pub.: 13 Sep '16, Pinned: 21 Aug '17
Abstract: Carbon dioxide (CO2) blowout from a wellbore is regarded as a potential environment risk of a CO2 capture and storage (CCS) project. In this paper, an assumed blowout of a wellbore was examined for China's Shenhua CCS demonstration project. The significant factors that influenced the diffusion of CO2 were identified by using a response surface method with the Box-Behnken experiment design. The numerical simulations showed that the mass emission rate of CO2 from the source and the ambient wind speed have significant influence on the area of interest (the area of high CO2 concentration above 30,000 ppm). There is a strong positive correlation between the mass emission rate and the area of interest, but there is a strong negative correlation between the ambient wind speed and the area of interest. Several other variables have very little influence on the area of interest, e.g., the temperature of CO2, ambient temperature, relative humidity, and stability class values. Due to the weather conditions at the Shenhua CCS demonstration site at the time of the modeled CO2 blowout, the largest diffusion distance of CO2 in the downwind direction did not exceed 200 m along the centerline. When the ambient wind speed is in the range of 0.1-2.0 m/s and the mass emission rate is in the range of 60-120 kg/s, the range of the diffusion of CO2 is at the most dangerous level (i.e., almost all Grade Four marks in the risk matrix). Therefore, if the injection of CO2 takes place in a region that has relatively low perennial wind speed, special attention should be paid to the formulation of pre-planned, emergency measures in case there is a leakage accident. The proposed risk matrix that classifies and grades blowout risks can be used as a reference for the development of appropriate regulations. This work may offer some indicators in developing risk profiles and emergency responses for CO2 blowouts.
Pub.: 27 Nov '16, Pinned: 21 Aug '17
Abstract: The abandonment process is a highly important part of project management for CO2 capture and storage (CCS) projects. For the first full procedure of a CO2 geological storage demonstration project in a deep saline aquifer in China, this paper describes the abandonment process of a CO2 operating well. The key idea that we advance is that wellbore integrity tests should be conducted before the abandonment, and consideration must be given to the CO2 corrosion resistance materials, the design method of sealing the plugs, monitoring tests (such as pressure tests), and the use of a long-term monitoring system (such as the original pressure test and a packer isolation test every year). According to Chinese regulations and related experience in the oil and gas industry, the factors chosen are the pressure factor, cap rock, potable water layer, unexploited resource layer, suspected leak path, perforated zone, productive hydrocarbon zone without perforation, and water-injection and waste-water treatment layers. We intuitively evaluate and quantify the plugged zones using the modified analytical hierarchy process (M-AHP) method to determine the positions of the plugs. Next, referring to the Chinese regulations on Well abandonment and inactive well practices, the last plug located in the Quaternary strata is compulsorily ensured, and the length of all plugs is also determined. Finally, the paper summarizes the methodology and presents suggestions for the abandonment process of the Shenhua CCS project. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.
Pub.: 28 Apr '17, Pinned: 21 Aug '17
Abstract: Recent proposals to produce and import hydrogen from Australia to Japan for electricity generation raise questions about how to compare the costs and feasibilities of different hydrogen import pathways. This paper establishes a framework for the comparison of technological, economic, and social costs and feasibility. The framework is then applied to 3 potential production and import case studies. First, a benchmark case study is considered which uses Australian brown coal from the Latrobe Valley combined with carbon capture and sequestration (CCS) technology. The second and third comparative case studies use renewable energy and electrolysis near port facilities in Karratha, Western Australia, using solar power exclusively as the renewable energy source, and Gladstone, Queensland, using a combination of onshore wind and solar-based generation. The study finds that comparative pilot project generation costs for the brown coal pathway are between approximately 5.9 and 15.4 yen/kWh cheaper than for solar and/or wind-based pathways. However, limitations of scaling up CCS, a limited brown coal supply, long-term reducing costs of renewables, and the prospect to develop complementary renewable infrastructure make a strong counterargument for investment in solar and wind pathways as an alternative to brown coal and CCS.
Pub.: 10 Jul '17, Pinned: 21 Aug '17
Abstract: Coastal vegetative habitats are known to be highly productive environments with a high ability to capture and store carbon. During disturbance this important function could be compromised as plant photosynthetic capacity, biomass, and/or growth are reduced. To evaluate effects of disturbance on CO2 capture in plants we performed a five-month manipulative experiment in a tropical seagrass (Thalassia hemprichii) meadow exposed to two intensity levels of shading and simulated grazing. We assessed CO2 capture potential (as net CO2 fixation) using areal productivity calculated from continuous measurements of diel photosynthetic rates, and estimates of plant morphology, biomass and productivity/respiration (P/R) ratios (from the literature). To better understand the plant capacity to coping with level of disturbance we also measured plant growth and resource allocation. We observed substantial reductions in seagrass areal productivity, biomass, and leaf area that together resulted in a negative daily carbon balance in the two shading treatments as well as in the high-intensity simulated grazing treatment. Additionally, based on the concentrations of soluble carbohydrates and starch in the rhizomes, we found that the main reserve sources for plant growth were reduced in all treatments except for the low-intensity simulated grazing treatment. If permanent, these combined adverse effects will reduce the plants' resilience and capacity to recover after disturbance. This might in turn have long-lasting and devastating effects on important ecosystem functions, including the carbon sequestration capacity of the seagrass system.
Pub.: 14 Jul '17, Pinned: 21 Aug '17
Abstract: Reducing meat consumption by humans and shifting to more efficient plant and animal protein sources could potentially free up large areas of pasture and feedcrop agricultural land for restoration or conversion to low-input high-diversity (LIHD) grasslands. LIHD grasslands improve biodiversity, carbon sequestration, erosion control, water storage, while also providing opportunities to produce biofuels. We examined the potential of converting pastures globally, and animal feedstock agricultural lands in the USA and Brazil, to LIHD biomass sources and the capacity of these systems to meet national energy demands via (1) cellulosic ethanol and (2) integrated gasification and combined cycle technology with Fischer-Tropsch hydrocarbon synthesis (IGCC-FT) processing. Our analyses, which we argue are conservative, indicate that large amounts of energy, far in excess of many country's current demands, can potentially be produced from IGCC-FT processing of grassland biomass grown on converted pastures, especially in tropical developing countries. Over 40 countries could meet ≥100% of their domestic demands for electricity, gasoline, and diesel. If energy products were shared between countries, the 95 countries with positive energy production yields could meet 46%, 28%, and 39% of their combined electricity, gasoline, and diesel demands, respectively. While it is clearly unrealistic to propose a 100% conversion of pasture lands to biofuel production, these analyses highlight the potential gains in ecosystem services and energy production that could theoretically be achieved on already-managed lands.
Pub.: 26 Jul '17, Pinned: 21 Aug '17
Abstract: Publication date: July 2017 Source:Algal Research, Volume 25 Author(s): David Pavlik, Yingkui Zhong, Carly Daiek, Wei Liao, Robert Morgan, William Clary, Yan Liu Pilot-scale algae photobioreactors (APBs) were used to culture microalga Chlorella vulgaris 395 on flue gas from the T.B. Simon Power Plant at Michigan State University. The flue gas was pumped directly into the APBs to provide a carbon source for the culture. Various photosynthetic photon flux densities (PPFD) (31, 104, 177, 531μmolm−2 s−1) and harvest ratios (20% and 30 %v/v) were applied on the photobioreactor to study their effects on algal growth. The results suggested that increasing PPFD significantly enhanced biomass production in terms of productivity, biomass concentration, and total dry weight at both harvest ratios. The highest biomass productivity of 0.40gL−1 d−1, along with corresponding biomass concentration of 1.30gL−1 and biomass dry weight of 40.0gd−1 APB−1, were achieved at the PPFD of 531μmolm−2 s−1 with the 30% harvest ratio. A photovoltaic (PV) powered APB was then simulated to carry out a techno-economic analysis. The mass balance analysis concluded that a one-metric-ton unit with 224m2 PV panels can generate 0.4kg of dry algae biomass with 51% protein content and sequester about 0.8kg of CO2 per day. The economic analysis indicated that a net positive revenue of $55,353 per year could be achieved for a system with an effective reactor volume of 100m3 and the corresponding PV panels of 22,400m2.
Pub.: 20 Jun '17, Pinned: 21 Aug '17
Abstract: Abstract: Significant reductions in CO2 emissions are required to limit the global temperature rise to 2°C. Carbon capture and storage (CCS) is a key enabling technology that can be applied to power generation and industrial processes to lower their carbon intensity. There are, however, several challenges that such a method of decarbonization poses when used in the context of natural gas (gas-CCS), especially for solvent-based (predominantly amines) post-combustion capture. These are related to: (i) the low CO2 partial pressure of the exhaust gases from gas-fired power plants (∼3-4%vol. CO2), which substantially limits the driving force for the capture process; (ii) their high O2 concentration (∼12-13%vol. O2), which can degrade the capture media via oxidative solvent degradation; and (iii) their high volumetric flow rates, which means large capture plants are needed. Such post-combustion gas-CCS features unavoidably lead to increased CO2 capture costs. This perspective aims to summarize the key technologies used to overcome these as a priority, including supplementary firing, humidified systems, exhaust gas recirculation and selective exhaust gas recirculation. These focus on the maximum CO2 levels achievable for each, as well as the electrical efficiencies attainable when the capture penalty is taken into account. Oxy-turbine cycles are also discussed as an alternative to post-combustion gas-CCS, indicating the main advantages and limitations of these systems together with the expected electrical efficiencies. Furthermore, we consider the challenges for scaling-up and deployment of these technologies at a commercial level to enable gas-CCS to play a crucial role in a low-carbon future. © 2017 The Authors. Greenhouse Gases: Science and Technology published by Society of Chemical Industry and John Wiley & Sons, Ltd.
Pub.: 10 Jul '17, Pinned: 21 Aug '17
Abstract: One of the most pressing environmental concerns of our age is the escalating level of atmospheric CO2 . Intensive efforts have been made to investigate advanced porous materials, especially porous organic polymers (POPs), as one type of the most promising candidates for carbon capture due to their extremely high porosity, structural diversity, and physicochemical stability. This review provides a critical and in-depth analysis of recent POP research as it pertains to carbon capture. The definitions and terminologies commonly used to evaluate the performance of POPs for carbon capture, including CO2 capacity, enthalpy, selectivity, and regeneration strategies, are summarized. A detailed correlation study between the structural and chemical features of POPs and their adsorption capacities is discussed, mainly focusing on the physical interactions and chemical reactions. Finally, a concise outlook for utilizing POPs for carbon capture is discussed, noting areas in which further work is needed to develop the next-generation POPs for practical applications.
Pub.: 26 Jul '17, Pinned: 21 Aug '17
Abstract: The current global dependence on fossil fuels to meet energy needs continues to increase. If a 2°C warming by 2100 is to be prevented, it will become important to adopt strategies that not only avoid CO2 emissions but also allow for the direct removal of CO2 from the atmosphere, enabling the intervention of climate change. The primary direct removal methods discussed in this review include land management and mineral carbonation in addition to bioenergy and direct air capture with carbon capture and reliable storage. These methods are discussed in detail, and their potential for CO2 removal is assessed. The global upper bound for annual CO2 removal was estimated to be 12, 10, 6, and 5 GtCO2/year for bioenergy with carbon capture and reliable storage (BECCS), direct air capture with reliable storage (DACS), land management, and mineral carbonation, respectively—giving a cumulative value of ~35 GtCO2/year. However, in the case of DACS, global data on the overlap of low-emission energy sources and reliable CO2 storage opportunities—set as a qualification for DAC viability—were unavailable, and the potential upper bound estimate is thus considered conservative. The upper bounds on the costs associated with the direct CO2 removal methods varied from approximately $100/tCO2 (land management, BECCS, and mineral carbonation) to $1000/tCO2 for DACS (again, these are the upper bounds for costs). In this review, these direct CO2 removal technologies are found to be technically viable and are potentially important options in preventing 2°C warming by 2100.For further resources related to this article, please visit the WIREs website.
Pub.: 28 Jul '17, Pinned: 21 Aug '17
Abstract: Publication date: Available online 8 June 2017 Source:Arabian Journal of Chemistry Author(s): Nezar H. Khdary, Mamdouh E. Abdelsalam Reducing carbon dioxide (CO2) is an area of great interest in current international efforts geared towards lowering emissions and combating global warming. In this work, amino-silica composite membranes were prepared and used to capture carbon dioxide. The surface of silica particles was chemically modified with amine to efficiently capture carbon dioxide. The phase separation technique was used to prepare the membranes from a composite containing polyvinylidene-fluoride-hexafluoropropylene (PVDF-HFP), amino-silica particles, acetone and water. SEM images revealed that the membranes composed of multi layers of porous polymer uniformly impregnated with silica particles. Both XRD and FTIR results have validated the perfect integration of silica particles within the polymeric network. The mechanical properties of the membrane is improved by the presence of silica particles as proved by the high tensile strength value (1.5 N/cm2) obtained for the PVDF-HFP/SiO2 membrane compared to (0.9 N/cm2) obtained for bare PVDF-HFP membrane. Also, we succeeded in recording SEM images to show that the plastic deformation of the film associated with the formation of macro-holes. To the best of our knowledge this is the first time for such results to be monitored with SEM to observe the macroscopic evolution of the structure. Additionally, the surface area was significantly increased from (3.8 m2/g) for bare PVDF-HFP membrane to (116.4 m2/g) for PVDF-HFP impregnated with silica particles. Moreover, the CO2 separation efficiency depends on both surface area and the quantity of amino-SiO2 added to the membrane. The addition of amino-silica particles leads to a significant uptake of carbon dioxide compared to non-modified polymer membrane. The results obtained indicated that combing the phase separation with amino silica particles provided a cost effective route to scaling up the synthesis of membranes that were mechanically stable and highly efficient at CO2 capture. Graphical abstract
Pub.: 10 Jun '17, Pinned: 21 Aug '17