High Temperature Carbon Dioxide Research Articles

Lithium-Containing Sorbents Based on Rice Waste for High-Temperature Carbon Dioxide Capture

This article studies the influence of the nature of the carrier from rice wastes on the sorption properties of lithium-containing sorbents, and also considers the impact of the modifying additive (K2CO3) and adsorption temperature on their characteristics. It has been shown that the sorption capacity of 11LiK/SiO2 at 500 °C reached 36%, which is associated with the formation of lithium orthosilicate in the sorbent composition, as well as with an increase in the specific surface area of the sorbent. After 12 cycles of sorption–desorption, it was found that the sorption capacity of 11LiK/SiO2 for CO2 decreased by only 8%. Rice waste-based sorbents have a high sorption capacity for CO2 at high temperatures, which allows them to be used for carbon dioxide capture. The results of this study indicate the prospects of using agricultural residues to create effective adsorbents that contribute to reducing environmental pollution and combating global warming.

Revealing the corrosion mechanism of an Al0.1CoCrFeNi high entropy alloy in high temperature carbon dioxide environment

The corrosion behavior of an Al0.1CoCrFeNi HEA in high temperature CO2 at 850 °C for different exposure periods was investigated using different characterization methods. Weight gain increased with extended exposure periods, yet it remained lower than most conventional alloys. A double-layer oxide film consisting of Cr2O3 and Al2O3 formed after 100 and 500 h of exposure, while a single layer of Cr2O3 developed after 1000 h of exposure. CoCrFeNi particles with an FCC structure were embedded in the oxide films irrespective of the exposure periods. Moreover, a transition zone containing numerous striped-like Al2O3 oxides along the grain boundaries was developed underneath the oxide films.

Investigation of Thermohydraulic Processes in Cooling Channels of a Blade for a High-Temperature Carbon Dioxide Turbine

Investigation of Thermohydraulic Processes in Cooling Channels of a Blade for a High-Temperature Carbon Dioxide Turbine

Thermodynamic Analysis of Semi-Closed Cycles with Oxy-Fuel Combustion and Carbon Dioxide-Steam Working Fluid

Reducing emissions of harmful substances during the production of electricity at thermal power plants is possible by the transition to semi-closed gas turbine cycles with oxy-fuel combustion and carbon dioxide-steam working fluid. Their main advantages compared with closed Rankine cycles with water vapor and open Brayton cycles with combustion products of the air-fuel mixture are the absence of the toxic substances formation danger and the effective separation of working fluid components based on the thermodynamic principle, which allows to subsequently dispose of high-purity carbon dioxide. This paper presents the results of the energy performance thermodynamic analysis of the most known oxy-fuel combustion power cycles with a carbon dioxide-steam working fluid. A technique for modeling thermal schemes of promising power units is described in detail, taking into account losses for cooling high-temperature carbon dioxide turbines, energy costs for the production and compression of oxygen, as well as compression of carbon dioxide before disposal. Based on the results of mathematical modeling, it was found that the net electrical efficiency for the semi-closed combined cycle with oxy-fuel combustion can reach 44.5% at a gas turbine inlet temperature of 1400°C, and 43.2% for the Allam cycle at 1100°C.

Diverse Carbonates in Exoplanet Oceans Promote the Carbon Cycle

Carbonate precipitation in oceans is essential for the carbonate-silicate cycle (inorganic carbon cycle) to maintain temperate climates. By considering the thermodynamics of carbonate chemistry, we demonstrate that the ocean pH decreases by approximately 0.5 for a factor of 10 increase in the atmospheric carbon dioxide content. The upper and lower limits of ocean pH are within 1–4 of each other, where the upper limit is buffered by carbonate precipitation and defines the ocean pH when the carbon cycle operates. If the carbonate compensation depth (CCD) resides above the ocean floor, then carbonate precipitation and the carbon cycle cease to operate. The CCD is deep (>40 km) for high ocean temperature and high atmospheric carbon dioxide content. Key divalent carbonates of magnesium, calcium and iron produce an increasingly wider parameter space of deep CCDs, suggesting that chemical diversity promotes the carbon cycle. The search for life from exoplanets will benefit by including chemically more diverse targets than Earth twins.

A phase-field study of stainless-steel oxidation from high-temperature carbon dioxide exposure

An electrochemical phase-field model has been developed to investigate the oxidation mechanisms of the 21-2N valve stainless steel alloy exposed to carbon dioxide at 973 K. Three oxide phases observed in oxidation experiments are included in the model: Mn3O4, Cr2O3, and MnCr2O4. Local charge neutrality and the conserved current condition are assumed to include the impact of the electric potential on oxidation, though it is found to be negligible when the system is electrically isolated. The sensitivity of the oxidation processes to the values of the diffusion mobilities is examined, and the oxidation rate is calibrated against experimental data by modifying the sensitive mobilities. We find that both inward oxygen and outward metal diffusion are important for oxidation. By investigating the impact of the order of the initial oxide layers, we find that Cr2O3 serves as a barrier to outward Mn diffusion. Moreover, controlling the initial oxide layer order can be used to limit oxidation.

Influence of Kinematic Parameters of Carbon Dioxide Turbine on Its Coefficient of Efficiency and Dimensions

To reduce carbon dioxide emissions into the environment, the energy sector develops oxygen-fuel energy cycles. One of the most promising cycles is the Allam cycle that features the highest efficiency of electricity generation among all others. One of the main elements of an oxy-fuel energy cycle is a high-temperature carbon dioxide turbine. The turbine’s working fluid and coolant consist predominantly of carbon dioxide at a supercritical pressure. Currently, there are no recommendations in the literature for the design of carbon dioxide turbines for an oxy-fuel energy system (OFES) operating according to the Allam cycle; therefore, there is a need to study the influence of parameters of the flow path of carbon dioxide turbines on its efficiency and overall performance. In this paper, we have presented the results of one-dimensional calculations of a flow path of the carbon dioxide turbine for the Allam cycle with a capacity of 300 MW, with an initial temperature and pressure of 1100 °C and 30 MPa, and an outlet pressure of 3 MPa. The study was carried out by varying the rotor speed, the reactivity level and the average diameter. Based on the results of one-dimensional calculations, we have found that the highest efficiency of the turbine flow path is achieved at a speed of 471 rad/s, a reactivity of 0.5, and an average diameter of 1.1 m for the first stage.

Grain boundary oxidation behavior of Ni15Cr alloy in high temperature carbon dioxide

The grain boundary (GB) corrosion behavior of Ni15Cr alloy in 650℃/1bar CO2 gas was investigated. The oxidation behavior of coherent twin boundary is similar to that of grain matrix due to the immobility of Cr. However, the incoherent twin boundary is prone to preferential intergranular oxidation due to the limited Cr diffusivity and the ingress of oxygen. Likewise, low angle GB is also susceptible to intergranular oxidation because Cr diffusion is not fast enough although it can induce GB migration and result in a protective scale at oxide tip. In contrast, random high angle GB is immune to intergranular oxidation because Cr can diffuse quickly to form a protective scale above GB with the formation of a large GB migration zone. Therefore, the oxidation behavior of GB is closely related to the diffusivity of Cr along GB which is determined by the GB structure.

Corrosion behavior and deuterium permeability of aluminide coating in high-temperature carbon dioxide atmosphere

In the thermionic space nuclear power, the hydrogen released by the moderator ZrH2 penetrates into the core and affects the power generation performance. Therefore, it is necessary to prepare hydrogen permeation barrier materials such as aluminide coatings on the surface of structural components. In this study, the aluminide coating was prepared by a composite low-temperature aluminizing process. Since the working environment was a mixture of helium (He) and carbon dioxide (CO2), the corrosion behavior of aluminide coatings in this atmosphere at 600 °C for 1000 h was studied. The results showed that an oxide layer of about 1–2.3 μm was formed on the surface, which was mainly composed of alumina, mixed with a small amount of chromia. There was a carbon-containing layer in the outer part of the oxide layer. The aluminide coating surface morphology was significantly improved, and CO2 gas had a repairing effect on the coating surface. In addition, the effect of CO2 gas on the hydrogen permeation resistance of aluminide coatings was comparatively investigated in pure D2 and D2 + CO2 atmospheres. The permeation reduction factors (PRF) under pure D2 and D2 + CO2 were 7.76 and 77.4, respectively, indicating that CO2 gas improved the PRF of the aluminide coatings by an order of magnitude.

Influence of high-temperature, high-pressure, and acidic conditions on the structure and properties of high-performance organic fibers

Abstract Aramid and poly(p-phenylene benzobisoxazole) (PBO) fibers are two of the most represented organic fibers possessing high strength, high modulus, excellent thermal stability, and chemical resistance, with great potential in oil and gas applications. The reliability of organic fibers for oil and gas applications were systematically evaluated by studying the corrosion behavior and mechanisms in high-temperature and high-pressure (HTHP) hydrogen sulfide (H2S) and carbon dioxide (CO2) corrosive environments. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), elemental analysis, density measurements, and single fiber tensile testing were conducted to study the surface morphology, chemical structure, crystal structure, thermal, and mechanical properties of aramid and PBO fibers, before and after corrosion. After corrosion, the crystallinities of aramid and PBO fibers decreased by 19.4 and 4.4%, respectively, whereas their tensile fracture strengths decreased by 50.34 and 28.18%, respectively. Hence, the corrosion resistance of PBO fiber is better than aramid fiber. The decrease in tensile properties of aramid and PBO fibers can be attributed to the higher internal porosity, more number of surface defects, and lower crystallinity after HTHP H2S/CO2 corrosion. This work provides some fundamental information regarding the selection of high-performance organic fibers for oil and gas applications.

Corrosion Behaviors of Heat-Resisting Alloys in High Temperature Carbon Dioxide.

The supercritical carbon dioxide Brayton cycle is a promising power conversion option for green energies, such as solar power and nuclear reactors. The material challenge is a tremendous obstacle for the reliable operation of such a cycle system. A large body of research indicates that high-temperature corrosion of heat-resisting alloys by CO2 results in severe oxidation and, in many cases, concurrent internal carburization. This paper mainly reviews the oxidation behavior, carburization behavior and stress corrosion behavior of heat-resisting alloys in high temperature CO2. Specifically, the main factors affecting the oxidation behavior of heat-resistant alloys, such as environmental parameters, surface condition and gaseous impurity, are discussed. Then, carburization is explored, especially the driving force of carburization and the consequences of carburization. Subsequently, the effects of the environmental parameters, alloy type and different oxide layers on the carburizing behavior are comprehensively reviewed. Finally, the effects of corrosion on the mechanical behavior and stress corrosion cracking behavior of heat-resisting alloys are also summarized. The corrosion performances of heat-resisting alloys in high temperature CO2 are systematically analyzed, and new scopes are proposed for future material research. The information provided in this work is valuable for the development of structural material for the supercritical carbon dioxide Brayton cycle.

Grain Boundary Oxidation Behavior of Ni15Cr Alloy in High Temperature Carbon Dioxide

Grain Boundary Oxidation Behavior of Ni15Cr Alloy in High Temperature Carbon Dioxide

Layered-perovskite oxides with in situ exsolved Co–Fe alloy nanoparticles as highly efficient electrodes for high-temperature carbon dioxide electrolysis

Ruddlesden–Popper phase oxide with exsolved Co–Fe alloy nanoparticles uniformly distributed on the surface (Co–Fe–STCF) exhibited outstanding activity towards CO2 electrolysis at elevated temperature.

Hierarchical ZnO/CuO nanostructures for room temperature detection of carbon dioxide

Hierarchical ZnO/CuO nanorods were grown on RF sputtered ZnO seed layer via the hydrothermal method and their characteristics are analyzed by high resolution scanning electron microscope (HRSEM) and X-ray diffraction (XRD) techniques to confirm the elemental composition, crystal structure, and morphology of the sensing material. The sensing performance of the carbon dioxide sensor was evaluated at room temperature under the various concentration of carbon dioxide gas from 150 ppm to 1000 ppm. The result obtained shows that the sensor yields a high response of 9.7 % for 1000 ppm of carbon dioxide gas with fast response and recovery time varied in the range of 1–4 min. The above results indicate the accomplishment of room temperature sensing with good reversibility and repeatability compared to conventional previously reported high temperature carbon dioxide sensors.

Direct Solid Oxide Electrolysis of Carbon Dioxide: Analysis of Performance and Processes

Chemical industries rely heavily on fossil resources for the production of carbon-based chemicals. A possible transformation towards sustainability is the usage of carbon dioxide as a source of carbon. Carbon dioxide is activated for follow-up reactions by its conversion to carbon monoxide. This can be accomplished by electrochemical reduction in solid oxide cells. In this work, we investigate the process performance of the direct high-temperature CO2 electrolysis by current-voltage characteristics (iV) and Electrochemical Impedance Spectroscopy (EIS) experiments. Variations of the operation parameters temperature, load, fuel utilization, feed gas ratio and flow rate show the versatility of the procedure with maintaining high current densities of 0.75 up to 1.5 A·cm−2, therefore resulting in high conversion rates. The potential of the high-temperature carbon dioxide electrolysis as a suitable enabler for the activation of CO2 as a chemical feedstock is therefore appointed and shown.

In-Situ Exsolution of Metal Nanoparticles in Solid Oxide Cells for Efficient Syngas Generation from Steam and Carbon Dioxide

The global sustainability targets require technologies to provide clean chemical and fuel feedstock molecules on a large scale often by employing renewable electricity as the energy input. Nowadays, syngas (carbon monoxide and hydrogen), the key intermediate for synthetic fuels through Fischer-Tropsch, is primarily generated from fossil fuels, which are responsible for gigantic energy consumption and green-house gases emissions. The co-electrolysis of carbon dioxide and steam in solid oxide electrolysis cells (SOECs) constitutes an emerging route for syngas feedstock production and thus, for storing the intermittent renewable electricity in the form of chemical bonds1.In SOECs, the Ni-based cermets are the most commonly employed materials as fuel electrodes due to their high electro-catalytic activity. Ni-based cermets, however, exhibit significant drawbacks, such as Ni coarsening under redox conditions and coking in the electrochemical active zone during CO2 electrolysis3. Perovskite oxides (ABO3) are the most promising alternatives due to their exceptional redox stability, extensive range of functionalities and the concept of exsolution. During exsolution, metallic nanoparticles of reducible species (usually from the B-site) grow at the surface of the perovskite oxide scaffold at reducing atmospheres, i.e. hydrogen-rich gas phase3 or imposition of high cathodic overpotentials4. Hence, perovskite oxide electrodes can be decorated with uniformly dispersed, anchored, coke and oxidation-resistant metal nanoparticles that can dramatically enhance the electrocatalytic performance and stability of the cell4.Compared to the slower exsolution via thermochemical reduction by hydrogen, the exsolution driven by electrochemical poling require only some minutes under high applied bias (~2.0 V) to form considerably higher population densities of metal nanoparticles on the oxide surface. Therefore, this method does not only offer, new pathways to electrode nanostructuring but also simplifies remarkably their preparation procedure4.Along these lines, here, we employ A-site deficient perovskites capable of exsolution, ((La,Ca)(Ti,M)O3 (LCT-M, M = Ni, Fe, Rh), as fuel electrodes (cathode) in ZrO2-based electrolyte supported cells for the high temperature steam and/or carbon dioxide electrolysis process. To achieve nucleation of the metal nanoparticles, reduction by both hydrogen and bias is investigated. Additionally, the effect of the imposed overpotential and gas atmosphere on the population, nature and shape of the particles is explored and it is correlated to the apparent cell performance during electrolysis.

High pressure-high temperature carbon dioxide adsorption to shale rocks using a volumetric method

With the current increase in hydrocarbon production from shale reservoirs, several methods have been applied to improve recovery from these unconventional oil and gas sources. Carbon dioxide (CO2) injection is one of the methods that can be used to increase oil recovery and store the CO2 in the reservoir via adsorption. This research investigates the CO2 storage applicability in the North East Oklahoma shale, which is part of the southern section of the Kansas Basin for CO2 storage, as well as the factors impacting the storage capacity. The shale mineralogy was initially identified using X-Ray Diffraction (XRD) analysis. CO2 adsorption on shale was measured using a volumetric-based adsorption apparatus. The effect of varying the CO2 phase, injection pressure, temperature, shale particle size, and shale volume in the sample cell was studied. Increasing the pressure resulted in an increase in adsorption, whereas increasing the temperature showed an opposite trend. No trend can be observed when decreasing the shale volume, since decreasing the volume using the volumetric adsorption apparatus will result in erroneous results. This research investigates and highlights the main factors that will impact CO2 adsorption to North East Oklahoma shale during CO2 injection in order to assess the applicability of CO2 injection storage purposes.

Encapsulation of Phase-Changing Eutectic Salts in Magnesium Oxide Fibers for High-Temperature Carbon Dioxide Capture: Beyond the Capacity-Stability Tradeoff.

Eutectic mixture (EM)-promoted MgO sorbents exhibit high CO2 sorption capacities but experience a significant decrease in uptake after multiple sorption-regeneration cycles due to EM movement and redistribution at high temperatures. Encapsulation of a pseudoliquid, phase-changing EM promoter with MgO may thus prevent the loss of active interface by confining the EM within a fixed area inside a MgO shell. In this work, we successfully embedded an EM composed of KNO3 and LiNO3 in a MgO fiber matrix via core-shell electrospinning. The synthesized sorbent achieved relatively high and steady sorption capacities, maintaining a stable uptake of ∼20 wt % after 25 sorption-regeneration cycles. The sorbent was also characterized using various techniques including in situ transmission electron microscopy (TEM) to describe its morphology, from which it was confirmed that the eutectic salt existed in distributed hollow pockets within the MgO fiber matrix and stayed confined within these fixed areas, favorably limiting its movement and redistribution when exposed to high temperatures where it exists in the liquid form. The EM may also be described as a glue that holds the fiber together, while MgO acts as a protective shell that prevents structural changes and rearrangement caused by EM movement, allowing the sorbent to retain its cyclic stability after multiple cycles and demonstrating its potential for industrial use after further improvement. Thus, the microencapsulation of a phase-changing EM material with pure MgO metal oxide was successfully achieved and might be explored for various material applications.

Study of CO2 and H2O direct co-electrolysis in an electrolyte-supported solid oxide electrolysis cell by aqueous tape casting technique

High temperature co-electrolysis based on Solid Oxide Electrolysis Cell (SOEC) is a very promising method to produce sustainable fuels and reduce greenhouse emissions. In this paper, the electrolyte-supported LSCM-GDC/SSZ/LSCF-GDC (LSCM: La0.75Sr0.25Cr0.5Mn0.5O3+δ) single cells are prepared and evaluated for high temperature steam and carbon dioxide direct co-electrolysis. And the fabrication of electrolyte layer is used with aqueous tape casting technique, which contributes to form a flat electrolyte layer with lower ohmic resistance in an eco-friendly way. LSCM fuel electrode exhibits good properties of redox stability and catalytic performance. During the experiment, different temperatures and volume ratios of H2O/CO2 are introduced into the cell to evaluate the electrochemical performance. In order to further verify the long-term performance of the cell, durability constant current SOEC test is carried out and the cell showed a stable voltage of 1.5 V for more than 100 h and throughout the duration of co-electrolysis. The results show that the electrolyte-supported SOEC using aqueous tape casting technique has good electrochemical performance and stability.

Thermodynamic and economic analysis of different cogeneration and trigeneration systems based on carbon dioxide vapor compression refrigeration systems

Carbon dioxide vapor compression refrigeration cycles operating at low evaporator temperatures represent a substantial waste energy recovery potential to generate useful products using the high-temperature carbon dioxide leaving the compressor. Despite this remarkable potential, there are limited investigations about waste energy recovery from these cycles for different applications. Using this as a motivation, in this work, different novel integrated cogeneration and trigeneration configurations are proposed based on a carbon dioxide parallel compression economization-vapor compression refrigeration cycle with a 1000 kW capacity and evaporator temperatures of −35 °C to −45 °C. The major originality of this work is the proposal and detailed techno-economic evaluation of several feasible cogeneration and trigeneration configurations for different practical applications. Different cycles and components are integrated into the carbon dioxide cycle including single and double stages water-lithium bromide absorption chillers, a single stage ammonia-water absorption refrigeration, a carbon dioxide-water heat exchanger and an organic Rankine cycle. The thermo-economic findings demonstrate that recovering the available thermal energy of carbon dioxide exiting the compressor would be very attractive both thermodynamically and economically to produce several useful outputs. More than 478 kW and 147 kW cooling (air conditioning) and refrigeration effects can be generated using the cogeneration configurations. Also, between 59.52 kW and 185.8 kW power can be generated depending on the configurations and organic fluid used, improving the coefficient of performance up to 18.0%. Moreover, 7763–9360 m3/year of domestic hot water can be generated by the trigeneration configurations, reducing the levelized cost of cooling up to 13%.