Dilute CO2 Research Articles

Polyethylenimine-incorporated zeolite 13X with mesoporosity for post-combustion CO2 capture

X-type zeolite with mesoporosity (Meso-13X) was prepared by using dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride as a mesopore-generating agent, and then modified with polyethylenimine (PEI) through a physical impregnation method to form a hybrid material (Meso-13X-PEI). Meso-13X with and without PEI was characterized by X-ray powder diffraction (XRD), N2 adsorption–desorption isotherm at 77K, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). Meso-13X-PEI exhibited higher CO2 capture capacity than PEI-modified zeolite 13X owing to its larger pore volume that accommodates more amine species inside the pore structure, and the mesoporosity also can facilitate dispersion of PEI molecules inside the pore channels. Compared to zeolite 13X, Meso-13X-PEI showed much higher CO2 capture selectivity (against N2) as well as higher CO2 capture capacity at relatively high temperature (e.g. 100°C) and dilute CO2 concentration relevant to post-combustion conditions.

TRAJECTORY OF CONTAMINATED PARTICLE IN INTENSIVE CARE UNIT OF HOSPITALS USING NUMERICAL MODELING

Primary objective of air-conditioning is to create an indoor air quality and thermal condition of comfort suitable for persons / patients, with minimum energy cost. In air-conditioning system, ventilation airflow rate is the amount of fresh outdoor air introduced into the room to dilute CO2, contaminants and odours etc. Numerical model solves mass, momentum and energy equations. The contaminated particle (infection) which is simulated with a Lagrangian particle tracking model and the same has been carried out by simulation. This is usually a small part of the supply airflow rate which is introduced and distributed into the room at proper flow rate, velocity, temperature and relative humidity so as to remove the thermal loads and obtain conditions of thermal comfort. This is filtered to remove contaminants, mixed with ventilation air and conditioned by cooling / heating and humidifying / dehumidifying before introduction into the room. The study concerns about the health risk of the airborne diseases (bacteria, fungus, viruses etc.) from the patient to the other people in the ICU of hospital. By observing the movement of contaminated particle, it is advisable to keep the nurse- station and health care staff near the inlet to keep them healthy.

Energy from CO2 using capacitive electrodes – A model for energy extraction cycles

A model is presented for the process of harvesting electrical energy from CO2 emissions using capacitive cells. The principle consists of controlling the mixing process of a concentrated CO2 gas stream with a dilute CO2 gas stream (as, for example, exhaust gas and air), thereby converting part of the released mixing energy into electrical energy. The model describes the transient reactive transport of CO2 gas absorbed in water or in monoethanolamine (MEA) solutions, under the assumption of local chemical equilibrium. The model combines the selective transport of ions through ion-exchange membranes, the accumulation of charge in the porous carbon electrodes and the coupling between the ionic current and the produced electrical current and power. We demonstrate that the model can be used to calculate the energy that can be extracted by mixing concentrated and dilute CO2 containing gas streams. Our calculation results for the process using MEA solutions have various counterintuitive features, including: 1. When dynamic equilibrium is reached in the cyclical process, the electrical charge in the anode is negative both during charging and discharging; 2. Placing an anion-exchange membrane (AEM) in the system is not required, the energy per cycle is just as large with or without an AEM.

Gas Heating and Formation of Single Linear Discharge Channel on Repetitive Branched Streamer Corona

SUMMARYUnder a nonuniform field in an atmospheric short gap, a branched pulse streamer corona changes to a single filamentary discharge (SFD) for a split second just before sparkover occurs. This SFD is a pretransitional phenomenon of sparkover. Therefore, it is very important to study SFD for an understanding of the sparkover mechanism. In this work, the SFD was recreated well by applying a highly repetitive impulse voltage to a needle‐plane gap in synthetic air with dilute CO2. The characteristics of the SFD, including the channel temperature, the propagation of the streamer head, and the formation process, were investigated by means of an intensified charge coupled‐device (ICCD) camera and a spectroscopic measurement system. It was found that the transition to SFD progresses with localized gas heating along the discharge channel. Furthermore, it was revealed that the SFD is a nonbranched positive streamer.

Ironic Chemicals

Most academic electrochemists and electrochemical engineers have rich and productive careers in research and take great pleasure in teaching. In the increasing statistics-obsessed world of academia, we monitor the impact of our research through publication metrics, while understanding that the interpretation of these measures is not straightforward. Another metric is seeing how our research impacts industrial application. In the high-tech, research intensive, example of copper electrodeposition for ULSI applications, we can observe industrial adaption of ideas for data analysis, paradigms for experimental programs, and through hiring of graduates. Nevertheless, many academic ideas will not be commercialized unless the original inventor or close associate is interested in the pathway from “invention to profit.”There are multiple pathways that can be taken including direct University licensing of intellectual property and the creation of spin-out companies from the University. From an educational perspective, opportunities exist for students to learn about intellectual property, the unique economics of start-ups, and entrepreneurship. Frameworks to help academics start up companies have emerged, as evidenced, for example, in the NSF I-Corps program.1 We briefly discuss our experience with attempts at licensing intellectual property in the area of laser electroplating. We then discuss ongoing efforts to start up a company, which we have named “Ironic Chemicals.” The company employs a chemolithoautotrophic bacterium, which extracts its energy from the oxidation of ferrous ions to ferric ions. The ferric ions are electrochemically reduced, and the iron electrolyte is re-circulated between the bioreactor and the electrochemical reactor. The organism is genetically modified to produce chemicals or liquid fuels from dilute CO2, eliminating agricultural feedstocks.We explain the technology behind Ironic Chemicals from both a scientific and business perspective, thereby illustrating how our instincts on speaking to potential investors were wrong. We discuss our experiences in customer discovery, as we attempt to convert an abstract business idea into a concrete understanding of what it will take to succeed. Furthermore, we share our experiences as we navigate questions such as, is the technology mature enough, how do we avoid conflicts of interest, and when should we talk with investors?1. https://www.nsf.gov/news/special_reports/i-corps/

Electrofuel Production Using Genetically Engineered Acidithiobacillus Ferrooxidans

We have been developing an electrofuels platform for the production of fuels and chemicals from dilute CO2 using electricity. The electricity can come from diverse sources which enables this technology to serve as an alternative means for storing and utilizing renewable energy. The process uses Acidothiobacillus ferrooxidans which are chemolithoautotrophic bacteria that can oxidize iron at low pH. The oxidized iron can be reduced electrochemically and recycled to the bioreactor. We have extensively characterized the growth of the wild type Acidothiobacillus ferrooxidans cells in continuous cultures and we have found that the use of chelators such as citric acid can enable growth at higher pH ranges which can improve growth efficiency, maximum cell yields, and steady state cell densities. We have also developed a platform for genetically modifying the Acidothiobacillus ferrooxidans cells and we have now expressed 4 different exogenous genes in this host organism. This is enabling us to explore new promoters and regulatory sequences to direct carbon flux through new synthetic metabolic pathways. For example, we have introduced a pathway for isobutyric acid production and the results of the characterization of these new cell lines will be presented. We have developed an optimized media formulation for combining the biochemical and electrochemical reactors together, and we have performed extended experiments of the integrated system using wild type cells, allowing us to calculate biomass produced per kWhr of electricity under different operating conditions. We have also build a prototype system with some process control to enable longer term evaluation of the electrofuels platform, and the latest results of this technology will be presented.

Gas Heating and Formation of Single Liner Discharge Channel on Repetitive Branched Streamer Corona

Under non-uniform field in atmospheric short-gap, the branched pulse streamer corona changes to single liner discharge channel (SLDC) for a split second just before sparkover occurs. This SLDC is pre-transitional phenomenon of sparkover. Therefore, it is very important to study SLDC for understanding sparkover process. In this work, the SLDC was recreated well by applying highly repetitive impulse voltage to needle to plane gap in synthetic air with dilute CO2. The characteristics of SLDC including the channel temperature, the propagation of streamer head and the formation process were revealed by means of ICCD cameras and a spectroscopic measurement system.

Mesoporous Alumina-Supported Amines as Potential Steam-Stable Adsorbents for Capturing CO2 from Simulated Flue Gas and Ambient Air

Carbon management by a means of CO2 capture from large stationary sources such as coal-fired power plants or from ambient air is a significant global issue. In the context of steam-stripping as a regeneration process for solid CO2 adsorbents, new adsorbent materials robust enough for direct contact with low temperature steam are needed. Here, mesoporous γ-alumina-supported poly(ethyleneimine) composite materials are prepared and evaluated as effective CO2 adsorbents, using dilute CO2 streams such as simulated flue gas (10% CO2) and ultradilute streams such as simulated ambient air (400 ppm CO2). In comparison to the silica-supported amine adsorbents typically utilized for CO2 capture applications, the alumina-supported amine adsorbents give better performance in terms of both capture capacity and amine efficiency, in particular, at ambient air conditions. In addition, the alumina-supported amines are stable over short multicycle temperature swing tests and, more importantly, appear to be more robust than the silica-based counterparts upon direct contact with steam. Thus, the resulting alumina-supported amines are suggested to be promising new materials for CO2 capture processes equipped with steam-stripping regeneration, especially from ultradilute gas streams.

Integration of carbon sequestration into curing process of precast concrete

The feasibility of integrating carbon sequestration into the curing of precast concrete products was investigated. Research assessed the CO2 uptake capacities of carbonation-cured concrete masonry units (CMU), concrete pavers, fibreglass-mesh reinforced cement board, cellulose-fibre board, and ladle slag fines. Three curing systems were used: (i) an open-inlet system using pressurized recovered CO2; (ii) a closed system using pressurized flue gas with 14% CO2; and (iii) a closed system using dilute CO2 under atmospheric pressure. The amount of carbon dioxide that could be sequestered in the annual North American output of the various precast concrete products was estimated. The net efficiency was calculated accounting for CO2 emissions penalty resulting from the capture, compression, and potential transport of the curing gases. Carbonation curing of the considered products could result in a net annual CO2 sequestration in US and Canada of approximately 1.8 million tonnes if recovered CO2 is used and one million tonnes if flue gas is used.

Adsorbent Materials for Carbon Dioxide Capture from Large Anthropogenic Point Sources

Since the time of the industrial revolution, the atmospheric CO(2) concentration has risen by nearly 35 % to its current level of 383 ppm. The increased carbon dioxide concentration in the atmosphere has been suggested to be a leading contributor to global climate change. To slow the increase, reductions in anthropogenic CO(2) emissions are necessary. Large emission point sources, such as fossil-fuel-based power generation facilities, are the first targets for these reductions. A benchmark, mature technology for the separation of dilute CO(2) from gas streams is via absorption with aqueous amines. However, the use of solid adsorbents is now being widely considered as an alternative, potentially less-energy-intensive separation technology. This Review describes the CO(2) adsorption behavior of several different classes of solid carbon dioxide adsorbents, including zeolites, activated carbons, calcium oxides, hydrotalcites, organic-inorganic hybrids, and metal-organic frameworks. These adsorbents are evaluated in terms of their equilibrium CO(2) capacities as well as other important parameters such as adsorption-desorption kinetics, operating windows, stability, and regenerability. The scope of currently available CO(2) adsorbents and their critical properties that will ultimately affect their incorporation into large-scale separation processes is presented.

Nuclear powered CO2 capture from the atmosphere

AbstractA process for capturing CO2 from the atmosphere was recently proposed. This process uses a closed cycle of sodium and calcium hydroxide, carbonate, and oxide transformations to capture dilute CO2 from the atmosphere and to generate a concentrated stream of CO2 that is amenable to sequestration or subsequent chemical transformations. In one of the process steps, a fossil‐fueled lime kiln is needed, which reduces the net CO2 capture of the process. It is proposed to replace the fossil‐fueled lime kiln with a modified kiln heated by a high‐temperature nuclear reactor. This will have the effect of eliminating the use of fossil fuels for the process and increasing the net CO2 capture. Although the process is suitable to support sequestration, the use of a nuclear power source for the process provides additional capabilities, and the captured CO2 may be combined with nuclear‐produced hydrogen to manufacture liquid fuels via Fischer‐Tropsch synthesis or other technologies. Conceivably, such plants would be carbon‐neutral and could be placed virtually anywhere without being tied to fossil fuel sources or geological sequestration sites. © 2009 American Institute of Chemical Engineers Environ Prog, 2009

Catalytic gasification of algae in supercritical water for biofuel production and carbon capture

There has been growing concern about the way cultivating biomass for the production of agro-biofuels competes with food production. To avoid this competition biomass production for biofuels will, in the long term, have to be completely decoupled from food production. This is where microalgae have enormous potential. Here we propose a novel process based on microalgae cultivation using dilute fossil CO2 emissions and the conversion of the algal biomass through a catalytic hydrothermal process. The resulting products are methane as a clean fuel and concentrated CO2 for sequestration. The proposed gasification process mineralizes nutrient-bearing organics completely. Here we show that complete gasification of microalgae (Spirulina platensis) to a methane-rich gas is now possible in supercritical water using ruthenium catalysts. 60–70% of the heating value contained in the algal biomass would be recovered as methane. Such an efficient algae-to-methane process opens up an elegant way to tackle both climate change and dependence on fossil natural gas without competing with food production.

The Effect of Different Flow Patterns on Anode Fluid Behaviors of Micro Direct Methanol Fuel Cells

Based on the visualization technology, we investigated experimentally the effect of different flow patterns on anode fluid behaviors of the μDMFC (Micro Direct Methanol Fuel Cell) with a transparent material under the same condition. Stainless steel mesh was utilized as the current collector which was distinct from the carbon cloth or carbon paper. Four dissimilar flow patterns were developed and tested. The observation of the effect of different flow patterns revealed that movements of dilute methanol solutions and CO2 gas bubbles in the dot and parallel flow fields represented more difficult, which could result in a decline of the μDMFC performance. The study also showed that a channel blocking in the single-serpentine flow field would be extremely terrible which could lead to a fuels leaking of the μDMFC, meanwhile the liquid-gas flow was more fluent and stable in a double-serpentine flow field. Therefore, due to its advantages, a double-serpentine flow pattern is more suitable for the μDMFC application compared with the other flow patterns.

Predicting instantaneous exhaust flowrates in a constant volume sampling system

The constant volume sampling (CVS) method has been used to support vehicle emissions testing for over 25 years and the ‘bag’ measurement of emissions is the key method that is used for legislative purposes. Bag measurements provide a single figure for CO, CO2, and NOx emissions species for the complete drive cycle, but provide no information on the profile throughout the test. Instantaneous emissions measurements undertaken on a second-by-second basis are carried out to assess catalyst and engine system performance. The key measurement for this approach is the determination of the instantaneous exhaust mass flowrate, which allows the instantaneous gravimetric emissions to be calculated. Being able to accurately measure instantaneous emissions carries its own challenges, but the mixing effects in the CVS system when using the CO2 tracer technique have been shown to compromise significantly the capability to determine exhaust volume flowrates accurately. The predicted time responses of dilute CO2 concentration, and the resulting over-underestimate of tailpipe volume flow, display adequate agreement with experimental results. The magnitude of these errors was determined by measurement to be in the region of a 1500 per cent overestimate during tip-outs.

Carbon recycling for zero-emission carbon-neutral transportation

AbstractConverting current internal combustion engines to operate in closed-cycle, lean-burn mode with pure oxygen could generate an exhaust stream of >99% carbon dioxide. The ease of capture of this carbon, relative to the dilute CO2 in current exhaust gases, points the way to a feasible route to zero-emission transportation. Prospects for implementing such an approach, which would include re-synthesis of fuel from the captured CO2 and water using renewable power, are considered.

ABSORPTION OF CO2 INTO AQUEOUS SOLUTIONS OF STERICALLY HINDERED METHYL AMINOETHANOL USING A HYDROPHOBIC MICROPOROUS HOLLOW FIBER CONTAINED CONTACTOR

ABSTRACT The absorption of dilute CO2 into aqueous solutions of sterically hindered 2-methyl aminoethanol (MAE) and the desorption of CO2 from CO2-loaded MAE solutions into N2 stream were investigated separately for the various combinations of operational variables, using a hydrophobic microporous hollow fiber (polytetrafluoroethylene, PTFE) contained gas-liquid contactor with aqueous solutions of MAE as liquid media in the shell side at 30°C. The absorption of CO2 in this contactor is governed by resistance in the liquid and hollow fiber phases. The resistance to diffusion in the hollow fiber phase amounts to 76–80% of the total resistance. Nevertheless, the absorption rates of CO2 into aqueous MAE solutions in this contactor are higher than those into aqueous solutions of sterically hindered 2-amino-2-methyl-1-propanol (AMP) in the stirred tank with a plane unbroken gas-liquid interface. The process of desorption of CO2 from CO2-loaded MAE solutions can be regarded as being controlled by diffusion and chemical reaction in both the stagnant film of the liquid phase and the liquid-filled pore of the hollow fiber phase under the slow or intermediate reaction regime. Both absorption and desorption rates under the simultaneous absorption-desorption operation in a single unit tend to approach the respective constant values as process time elapses. The total absorption rate here seems to be almost balanced with the total desorpion rate at the constant mass transfer rate periods.

Solubility of dilute SO2 and CO2 in dimethyl sulfoxide

The solubility of SO2 and CO2 in dimethyl sulfoxide has been determined in the temperature range from 293.15 to 313.15 K and partial pressure of SO2 from 0.15 to 2.62 kPa, and the partial pressure of CO2 from 5 to 18 kPa. A solubility model is proposed and the solubilities calculated by the model show good agreement with the experimental data.

Ventilation Control Strategy Using the Supply CO2 Concentration Setpoint

This paper proposes a new ventilation control strategy applied to multiple spaces subject to variable occupancy. The strategy specified for real-time, online ventilation control takes advantage of uninitiated air from some overventilated spaces to be used as fresh outdoor air in order to reduce system energy use while maintaining the indoor air quality (IAQ) in each space. This proposed strategy maintains a supply CO2 concentration setpoint low enough to dilute CO2 generated by full occupancy in critical zones. The supply CO2 concentration setpoint could be determined online using the monitored zone airflow rates. It is tested and evaluated by making comparisons with other known control strategies. An existing VAV system installed at the École de technologie supérieure is used to evaluate this new strategy. The outdoor air fraction and associated energy use of investigated ventilation control strategies are calculated using the VAV system component models that are developed and validated against the monitored data.

Ore-forming fluids associated with granite-hosted gold mineralization at the Sanshandao deposit, Jiaodong gold province, China

The Sanshandao gold deposit, with total resources of more than 60 t of gold, is located in the Jiaodong gold province, the most important gold province of China. The deposit is a typical highly fractured and altered, disseminated gold system, with high-grade, quartz-sulphide vein/veinlet stockworks that cut Mesozoic granodiorite. There are four stages of veins that developed in the following sequence: (1) quartz-K-feldspar-sericite; (2) quartz-pyrite±arsenopyrite; (3) quartz-base metal sulfide; and (4) quartz-carbonate. Fluid inclusions in quartz and calcite in vein/veinlet stockworks contain C-O-H fluids of three main types. The first type consists of dilute CO2–H2O fluids coeval with the early vein stage. Molar volumes of these CO2–H2O fluid inclusions, ranging from 50–60 cm3/mol, yield estimated minimum trapping pressures of ≥3 kbar. Homogenization temperatures, obtained mainly from CO2–H2O inclusions with lower CO2 concentration, range from 267–375 °C. The second inclusion type, with a CO2–H2O±CH4 composition, was trapped during the main mineralizing stages. These fluids may reflect the CO2–H2O fluids that were modified by fluid/rock reactions with altered wallrocks. Isochores for CO2-H2O±CH4 inclusions, with homogenization temperatures ranging from 204–325 °C and molar volumes from 55 to 70 cm3/mol, provide an estimated minimum trapping pressure of 1.2 kbar. The third inclusion type, aqueous inclusions, trapped in cross-cutting microfractures in quartz and randomly in calcite, are post-mineralization, and have homogenization temperatures between 143–228 °C and salinities from 0.71–7.86 wt% NaCl equiv. Stable isotope data show that the metamorphic fluid contribution is minimal and that ore fluids are of magmatic origin, most likely sourced from 120–126 Ma mafic to intermediate dikes. This is consistent with the carbonic nature of the fluid, and the cross-cutting nature of those deposits relative to the host Mesozoic granitoid.

Dow to close pet plant in Pisticci, Italy

This paper evaluates the opportunities and associated costs for post-combustion capture at a world-scale complex refinery. It is concluded that it is technically feasible to apply post-combustion capture at such a refinery. The costs for capture and sequestration from a gasifier are calculated to be lowest at about 30 Euro per ton; this process currently already produces a concentrated CO2 stream. Next, the CO2 source most suited for capture appears to be a combined stack, but there are a number of other sources that may be targeted at comparable costs. In total these sources may form about 40% of the overall refinery emissions. Our evaluations show the costs of capture from such sources based on available amine technology will be in the range of 90–120 Euro per ton, which is about 3–4 times higher than the current carbon trading values. The capture of CO2 from a large amount of smaller CO2 sources will bring along even much higher costs. A high-level study of the CO2 emissions profile of a number of Shell refineries shows that, typically, up to 50% of the emitted CO2 may be captured at similar costs. About 10–20% of concentrated CO2 associated with hydrogen manufacturing may be captured at lower costs. The remainder of emitted dilute CO2 will bring along significantly higher costs. Based on this study, it is concluded for the justification of the implementation of post-combustion capture at refineries, either a significant increase in carbon trading values, mandatory regulations, or a major technological break-through is required.