Continuous CO2 Research Articles

CW CO2 laser cutting of multiple-layer blended fabric

Today, almost any material can be cut with a laser. CO2 laser cutting is a promising technology for textiles, offering precision and flexibility. Unlike synthetic textiles, natural fibers such as cotton and wool do not melt when exposed to the heat of the laser beam, which can cause undesirable discoloration during laser treatment. Therefore, the power of the laser source and the speed of the process, as well as accurate matching to the material being processed, are critical to achieving optimal results in laser cutting of such blended fabrics. In this work, a theoretical model based on the energy balance equation is developed to estimate the cutting depth and speed by calculating the effective thermal properties of a fabric composed of two different fibers. By altering the laser parameters, a sequence of trials was performed on Fustian fabric comprising 45 % wool and 55 % polyester. The results indicate that a continuous CO2 laser with an output power of 45 watts at a speed of 30 mm/s can cut 10 layers of fabric while maintaining superior quality. The suggested model is in line with the experimental findings. Moreover, the theoretical framework correctly predicts how varying blend ratios in the material affect the cutting process based on further tests carried out. These results are significant for the future development of laser technology in the apparel industry.

Numerical investigation of CO2-carbonated water-alternating-gas on enhanced oil recovery and geological carbon storage

This study investigates the potential of a novel CO2-carbonated water-alternating-gas (CWAG) injection method for enhanced oil recovery (EOR) and geological carbon storage. The Weyburn fluid data acquired from Canada are used in a compositional reservoir simulation of a CO2-CWAG case study with seven cycles in order to analyze the effects of carbonated water (CW) upon the oil recovery and CO2 storage capacity of a multi-phase CO2/brine/oil system. The study includes an assessment of the CO2 plume propagation and retention via structural, residual, and solubility trapping mechanisms. The numerical results demonstrate that CO2-CWAG yields a 6.7% increase in oil recovery compared to continuous CO2 flooding (from 68.4% to 73.0%) and a 1.4% increase compared to CO2-WAG (from 72.0% to 73.0%). During the CO2-CWAG operation, increasing the molarity of CO2 from 0.0 mol/L to 1.2 mol/L in carbonated water results in a 6.7% increase in the amount of geologically stored CO2 (from 6191 tons to 6608 tons). In brief, CO2-CWAG improves not only oil recovery but also CO2 storage capacity in terms of the three trapping mechanisms, thus making it a promising low-carbon EOR method that could help reduce CO2 emissions in the oil and gas industry.

Study on Enhanced Oil Recovery Mechanism of CO2 Miscible Flooding in Heterogeneous Reservoirs under Different Injection Methods.

The mechanism by which oil recovery can be enhanced by different injection methods of CO2 miscible flooding to alleviate the influence of heterogeneous reservoirs was studied to optimize the injection methods, further improving oil recovery. According to the reservoir heterogeneity characteristics of the TI oil formation group in Lunnan Oilfield, a 1 m double-layer long core was designed and prepared for four CO2 miscible displacement experiments with different injection methods. By analyzing the variation in the injection-production parameters, the displacement effects of different injection methods were compared, and the mechanism of enhanced oil recovery (EOR) was summarized. The results indicate the following. ① The displacement efficiency of the different injection methods lies in the following order. Alternate CO2-water injection, continuous CO2 flooding, cyclic CO2 flooding, and alternate CO2-hydrocarbon gas injection. ② The recovery of crude oil via CO2 miscible flooding in heterogeneous reservoirs relies on both convective diffusion and miscible mass transfer. Convective diffusion depends mainly on control of the displacement pressure differential and the plugging of preferential seepage channels in high-permeability areas, while miscible mass transfer depends mainly on the swept range of the convective diffusion and the degree of miscibility between CO2 and crude oil. ③ To improve the recovery efficiency of CO2 miscible flooding in heterogeneous reservoirs, it is necessary to choose an injection method that optimizes these two aspects.

Characteristics of continuous CO2 hydrate formation process using a NetMIX reactor

A new continuous process to obtain CO2 hydrates, which is scalable, without losing its heat removing capacity is presented. Hydrate formation is highly exothermic, and jacketed stirred tank reactors configurations have limitations in heat removal. Experiments to obtain CO2 hydrates (P = 27 bar, T = 2.7, 3.8 and 4.8 °C, CO2/water mass flow ratios of 0.02, 0.10 and 0.18) were perfomed. Hydrate formation in the NetMIX is very fast (seconds). The outstanding performance is due to the high gas–liquid contact and the capability in removing the heat released at the rate it is formed. The 0.18 CO2/water mass flow ratio formed hydrates at a higher concentration. Results suggest the gas uptake in the hydrate formed in this process is higher than those produced in batch systems. The process presented in this work is a promising alternative for the sequestration of CO2 due to the advantages of this device both in heat removal and enhanced mass transfer.

Carbon-neutral synfuel production via continuous solar H2O and CO2 gasification of oil palm empty fruit bunch

Solar gasification offers a promising carbon-neutral pathway to thermochemically convert waste biomass and solar energy into synfuel. In this study, a thermodynamic analysis of solar gasification of oil palm empty fruit bunch (EFB) with H2O and CO2 gasifying agents was first performed to predict equilibrium product distribution. Subsequently, on-sun continuous solar gasification of EFB was experimentally carried out in a solar particle-fed gasifier to evaluate the influence of gasifying agent types (H2O and CO2), gasifying agent/EFB molar ratios (1.8–3.4), temperatures (1050–1350 °C), and to assess overall process feasibility and reliability. As a result, solar EFB gasification performed efficiently with both H2O and CO2 gasifying agents under continuous on-sun operation. Syngas product composition and gasification reaction rate strongly depended on gasifying agent type. Increasing temperature enhanced syngas yield and quality, and changed the CO/H2 mole ratio, especially in EFB + CO2 gasification. A gasifying agent/EFB molar ratio of 2.6 (slight excess of gasifying agents) and a temperature of 1300 °C were shown to be optimal for continuous solar EFB gasification. The maximum total syngas yield above 76 mmol/gdry_EFB, syngas lower heating value above 22 kJ/gdry_EFB, and energy upgrade factor above 1.37 were achieved from both EFB + H2O and EFB + CO2 gasification, which closely approached their theoretical equilibrium values. The maximum carbon conversion exceeding 93% and solar-to-fuel energy conversion efficiency up to 19.3% were achieved, demonstrating efficient EFB-to-synfuel conversion performance. Continuous solar EFB gasification with both H2O and CO2 was thus established to be a reliable process for EFB waste biomass valorization into high-quality and carbon-neutral synfuel.

Continuous atmospheric in-situ measurements of the CH4/CO ratio at the Mt. Cimone station (Italy, 2165 m a.s.l.) and their possible use for estimating regional CH4 emissions

Methane (CH4) is an important climate forcer, contributing about 17% of the total radiative forcing by long living greenhouse gases. The Po basin is one of the most polluted and densely populated areas in Europe representing an important source region for CH4.The aim of this work was to test an inter-species correlation approach to derive estimates of anthropogenic CH4 emissions for the period 2015–2019 from the Po basin by combining CO bottom-up inventory data and continuous CH4 and CO observations from a mountain site in the northern Italy. The tested methodology suggested lower emissions in respect to EDGAR (−17%) and the Italian National Inventory (−40%) for the Po basin. However, despite the two bottom-up inventories, the emissions derived from the atmospheric observations reported an increasing tendency from 2015 to 2019 for the CH4 emissions. A sensitivity study revealed that using different subsets of the atmospheric observations implied a difference of 26% in the CH4 emission estimates. The highest agreement with two bottom-up CH4 inventories (EDGAR and the Italian national inventory) were obtained when atmospheric data were strictly selected for periods representative of air mass transport from the Po basin.Our study identified various challenges when using this methodology as a benchmark to verify bottom-up CH4 inventories. Issues could be attributed to the annual aggregation of the proxies used to derive the emission amounts, to the CO bottom-up inventory used as input information and to the relatively high sensitivity of the results to the different subsets of the atmospheric observations. However, the use of different bottom-up inventories as input data for CO emissions can potentially provide information that should be carefully considered for the purpose of integrating CH4 bottom-up inventories.

Preparation of organic-filled compatible nanocomposite membranes for enhanced CO2 permselectivity

Ideally structured nanocomposite membranes may possess the maximum desired separation properties of both filler particles and the host polymer matrix. To approach this goal in this study, some nanocomposite dense membranes were prepared using Pebax 1657 and polyaniline nanofiber (PANI) with closed structural properties in their different concentrations by applying various ethanol/water solvent mixtures and the solution method casting and solvent evaporation phase inversion. The structural characteristics of the membranes were evaluated using SEM, FTIR (ATR), and XRD analysis and then their CO2 and CH4 permeabilities were measured. The structural analysis revealed that the prepared nanocomposite membranes have defect-free structures and the amorphous PANI nanofibers were dispersed uniformly within the nanocomposite membranes leading to their lower crystallinities. As the nanofiber loading increased in the continuous phase, both CO2 permeability and selectivity of the nanocomposite membranes were increased simultaneously and passed over the 1991 Robeson upper bound limit and approached that of 2008. CO2 permeability and ideal CO2/CH4 selectivity of the nanocomposite membrane loaded by 10 wt. % of the PANI nanofibers were increased to 121.2 Barrer and 33, respectively, revealing 64 and 40 % increments.

Continuous CO2 abatement via integrated carbon capture and conversion over Ni-MgO-Al2O3 dual-functional materials

Massive emission of CO2 is one of the main contributors to global warming, and CO2 capture, utilization and storage (CCUS) was proposed as an indispensable option for carbon reduction. Recently, integrated carbon capture and conversion (ICCC) was regarded as a potential approach to lower the cost of CCUS, and development of efficient dual-functional materials (DFMs) is among the top priority in the area. Herein, Ni-MgO-Al2O3 DFMs were prepared by calcination of Ni-impregnated Mg-Al layered double hydroxide (MgAl-LDH), as such, the pre-loaded Ni species was actively involved in the decomposition of MgAl-LDH, therefore the synergy and balance of the adsorption and catalytic functionalities for ICCC can be promoted in the resulted DFMs. The optimized sample (20NiMgAl(500)) showed excellent ICCC performance. At 300 °C, continuous abatement of CO2 from simulated flue gas (15 vol.%CO2/N2) was achieved with an excellent efficiency of 280 L·h−1·kg−1. Composition analysis of the effluent gas demonstrated that over 97 % CO2 in the feed could be captured, and over 95 % of the captured CO2 was converted to CH4 with ∼ 100 % selectivity. Full retention of the adsorption capacity was observed for 10 adsorption-methanation cycles, and the post-reaction characterization of the DFMs indicated little structure change. This work may pave a way to the practical application of the ICCC technology, and also inspire other integration approaches between CO2 capture and the following mitigation technologies.

Chemically bonded BiVO4/Bi19Cl3S27 heterojunction with fast hole extraction dynamics for continuous CO2 photoreduction

Surface charge localization and inferior charge transfer efficiency seriously restrict the supply of reactive hydrogen and the reaction dynamics of CO2 photoreduction performance of photocatalysts. Herein, chemically bonded BiVO4/Bi19Cl3S27 (BVO/BCS) S-scheme heterojunction with a strong internal electric field is designed. Experimental and density function theory calculation results confirm that the elaborated heterojunction accelerates the vectorial migration of photogenerated charges from BiVO4 to Bi19Cl3S27 via the interfacial chemical bonding interactions (i.e., Bi-O and Bi-S bonds) between Bi atoms of BVO and S atoms of BCS or Bi atoms of BCS and O atoms of BVO under light irradiation, breaking the interfacial barrier and surface charge localization of Bi19Cl3S27, and further decreasing the energy of reactive hydrogen generation, CO2 absorption and activation. The separation efficiency of photogenerated carriers is much more efficient than that counterpart individual in BVO/BCS S-scheme heterojunction system. As a result, BVO/BCS heterojunction exhibits a significantly improved continuous photocatalytic performance for CO2 reduction and the 24 ​h CO yield reaches 678.27 ​μmol·g−1. This work provides an atomic-level insight into charge transfer kinetics and CO2 reduction mechanism in S-scheme heterojunction.

Chlorophyll fluorescence parameter as a predictor of tomato growth and yield under CO2 enrichment in protective cultivation

Greenhouse crops production has been improved by CO2 enrichment commercially. The impact of a threshold level of elevated CO2 (e[CO2]) on the effective quantum yield of photosystem II (ФPSII, chlorophyll fluorescence parameter), which is linked to crop yield, crop growth and fruit quality, is still uncertain. Many previous studies cultivated C3 crops under 550–700 µmol·mol-1, not beyond this range. Hence, tomato plants were grown under ambient CO2 (a[CO2], 500 µmol·mol-1) and e[CO2] (700, 850, and 1000 µmol·mol-1): named as EC700, EC850, and EC1000, respectively, under uniform environmental conditions for two growing seasons to investigate the response of ФPSII along with four photosynthetically active radiation intensities and plant growth to continuous CO2 concentration [CO2]. Under four constant PAR intensities during autumn-winter 2020 and spring-summer 2021, the order of mean ФPSII values under e[CO2] were explored as EC700 > EC1000 > EC850 > a[CO2] and EC700 > EC850 > EC1000 > a[CO2], respectively. The optimum total fruit yield was stimulated under EC700 by 74.04% and 55.86% during autumn-winter 2020 and spring-summer 2021, respectively, as compared to a[CO2]. The results showed that water use efficiency related to yield (WUEy) were enhanced by reducing the stomatal conductance under e[CO2] as compared to a[CO2]. Optimum WUEy was enhanced by 55.91–210.87% under EC700 compared to a[CO2]. The principal component analysis showed strong correlation of ФPSII with plant height, yield and water use efficiency in autumn-winter 2020 and spring-summer 2021, LAI in spring-summer 2021, weak correlation with stem diamter in autumn-winter 2020 and spring-summer 2021, indicated the strong effect of ФPSII on plant growth and yield under e[CO2]. The EC1000 in autumn-winter 2020 and EC700 in spring-summer 2021 were found more influential by the analytic hierarchy process to get optimum crop production, no significant difference between the ranking scores of EC1000 and EC700 during autumn-winter 2020 was found. Thus, the overall optimum impact of e[CO2] on tomato growth was explored under EC700. The findings of this study are beneficial to greenhouses crops production commercially and could be used as references for validating the climate change impact modelling.

Seasonal Environmental Controls on Soil CO2 Dynamics at a High CO2 Flux Sites (Piton de la Fournaise and Mayotte Volcanoes)

AbstractEnvironmental parameters drive seasonal soil CO2 efflux toward the atmosphere. However, their influence is not fully understood in contexts of high CO2 fluxes where CO2 accumulates in the subsurface. A prime example are volcanoes subject to continuous CO2 diffuse degassing rising from deep magmatic reservoirs, through the subsurface and up to the atmosphere. For many of these volcanoes where soil CO2 is monitored, a seasonal influence of the atmosphere and water table is observed but not characterized. Here, we compare variations of air temperature, atmospheric pressure, rainfall and water table level with near‐surface soil CO2 concentration by performing a time‐lagged detrended cross‐correlation analysis on years‐long time series from the volcanoes of Piton de la Fournaise and Mayotte. At Piton de la Fournaise, soil CO2 variations correlate best with air temperature variations (0.81) and water table variations (0.74). In Mayotte, soil CO2 variations correlate best with atmospheric pressure variations (−0.95). We propose that at Piton de la Fournaise, the thick vadose zone and high permeability favor CO2 transfer by thermal convection. Additionally, energy transfer is decoupled from mass transfer. Slow heat transfer from the atmosphere down to the accumulated CO2 layers in the subsurface results in a delayed influence of air temperature and of the water table level on the thermal gradient between the subsurface and the atmosphere, and consequently on the efficiency of the CO2 transfer. In Mayotte, we propose that the thin vadose zone and the presence of a network of large fractures favor CO2 transfer by barometric pumping.

CO2‐Enhanced Production and Synthesis of 2,5‐ Furandicarboxylic Acid under CO2 Flow through Henkel Reaction

AbstractThe present study investigated the preparation of 2,5‐furandicarboxylic acid (FDCA) via the Henkel reaction between furoic acid alkali metal salts and zinc chloride under a continuous CO2 flow at atmospheric pressure. The results obtained were compared with those of previous studies that used high‐pressure conditions or toxic cadmium catalysts. The pathways and rate‐determining steps of the reaction are revealed for the first time. Furthermore, the enhanced formation of FDCA through the promotion of carboxyl exchange and rearrangement during the reaction under a CO2 flow was examined. The CO2‐rich environment afforded a high FDCA yield of 86.30 %, which is the highest yield obtained to date using the Henkel reaction. The findings of this study offer economically improved conditions for large‐scale FDCA production.

Reservoir heterogeneity controls of CO2-EOR and storage potentials in residual oil zones: Insights from numerical simulations

Residual oil zones (ROZs) have large potential for CO2 enhanced oil recovery (EOR) and geologic storage. During CO2 injection, the migration of CO2 in ROZs controls the performance of both EOR and storage. However, it has not been clearly visualized and understood that how geological heterogeneity factors control the transport of CO2 in ROZs. In this study, the oil recovery performance and geologic storage potential during continuous CO2 injection in a representative ROZ are studied based on geostatistical modelling and high-fidelity three-phase flow simulation. We examined the influence of autocorrelation length of permeability, global heterogeneity (Dykstra–Parsons coefficient), and permeability anisotropy on cumulative oil recovery and CO2 retention fraction. Simulation results indicate that, as the permeability autocorrelation length increases, the cumulative oil recovery and CO2 storage efficiency decrease. This results from the accelerated migration of CO2 along high permeability zones (i.e., gas channeling). The increase in global heterogeneity and permeability anisotropies can lead to low oil recovery and poor CO2 sequestration performance, depending on the degree of CO2 channeling. The net utilization ratio of CO2 (CO2 retained/oil produced) unfavorably increases with both autocorrelation length and Dykstra–Parsons coefficient, but decreases with the increase in kv/kh. Such a decrease is attributed to enlarged swept volume induced by gravity override. The study provides important implications for field-scale CO2 EOR and storage applications in ROZs.

Methane and carbon dioxide fluxes at high spatiotemporal resolution from a small temperate lake

Lakes are hotspots for CH4 and CO2 effluxes, but their magnitude and underlying drivers are still uncertain due to high spatiotemporal variation within and between lakes. We measured CH4 and CO2 fluxes at high temporal (hourly) and spatial resolution (approx. 13 m) using 24 automatic floating chambers equipped with continuously recording sensors that enabled the determination of diffusive and ebullitive gas fluxes. Additionally, we measured potential drivers such as weather patterns, water temperature, and O2 above the sediment. During five days in autumn 2021, we conducted measurements at 88 sites in a small, shallow eutrophic Danish Lake. CH4 ebullition was intense (mean 54.8 μmol m−2 h−1) and showed pronounced spatiotemporal variation. Ebullition rates were highest in deeper, hypoxic water (5–7 m). Diffusive CH4 fluxes were 4-fold lower (mean 15.0 μmol m−2 h−1) and spatially less variable than ebullitive fluxes, and significantly lower above hard sediments and submerged macrophyte stands. CO2 concentration in surface waters was permanently supersaturated at the mid-lake station, and diffusive fluxes (mean 919 μmol m−2 h−1) tended to be higher from deeper waters and increased with wind speed. To obtain mean whole-lake fluxes within an uncertainty of 20 %, we estimated that 72 sites for CH4 ebullition, 39 sites for diffusive CH4 fluxes and 27 sites for diffusive CO2 fluxes would be required. Thus, accurate whole-lake quantification of the dominant ebullitive CH4 flux requires simultaneous operation of many automated floating chambers. High spatiotemporal variability challenges the identification of essential drivers and current methods for upscaling lake CH4 and CO2 fluxes. We successfully overcame this challenge by using automatic floating chambers, which offer continuous CH4 and CO2 flux measurements at high temporal resolution and, thus, are an improvement over existing approaches.

Accurate evaluation of the Birch effect requires continuous CO2 measurements and relevant controls

The influence of dry-wet cycles (DWC) on soil organic carbon (SOC) decomposition is still debated given the somehow controversial results observed in the literature. The objective of this study was to evaluate the effects of DWC on SOC mineralization relative to various moisture controls in 7 treatments from two long-term French field experiments presenting contrasted SOC concentrations. A laboratory incubation was conducted for 97 days to quantify CO2 emissions upon four soil moisture scenarios: continuously wet scenario at pF 1.5 (WET), continuously moderate wet scenario at pF 2.5 (MWET), continuously dry scenario at pF 4.2 (DRY) and dry-wet cycles (DWC) between pF 1.5 and 4.2. Each cycle contained two phases, 10 days of drying phase, followed by 7 days of moist phase after rewetting. The drying phase consisted of adding silica gel to the incubation jars to absorb water in the soil and then gradually drying the soil. We also calculated the SOC mineralization that would correspond to the average water content in DWC (mean_DWC). Our results showed that across all treatments the daily carbon mineralization rate increased with soil moisture (WET > MWET > DRY). In DWC scenario, mineralization rates fluctuated with the changes in soil moisture. As soils dried, daily mineralization rates decreased and the subsequent soil rewetting, to pF 1.5, caused a rapid mineralization flush or “Birch effect”. However, these flushes did not compensate for the low mineralization rates in the drying phase as the cumulative mineralization was not higher in the DWC scenario compared to the mean_DWC which was the scenario with equivalent water content as the DWC. We also observed that not accounting the CO2 emissions in the drying phase, could lead to an overestimation of the effect of DWC. We recommend to measure continuously the soil respiration during dry-wet experiments and to compare the CO2 emitted in DWC with a control that has a water content equivalent to the average water content in DWC. In addition, we questioned the importance of the effect of DWC on overall soil respiration.

Liquified Petroleum Gas-Fuelled Vehicle CO2 Emission Modelling Based on Portable Emission Measurement System, On-Board Diagnostics Data, and Gradient-Boosting Machine Learning

One method to reduce CO2 emissions from vehicle exhaust is the use of liquified petroleum gas (LPG) fuel. The global use of this fuel is high in European countries such as Poland, Romania, and Italy. There are a small number of computational models for the purpose of estimating the emissions of LPG vehicles. This work is one of the first to present a methodology for developing microscale CO2 emission models for LPG vehicles. The developed model is based on data from road tests using the portable emission measurement system (PEMS) and on-board diagnostic (OBDII) interface. This model was created from a previous exploratory data analysis while using gradient-boosting machine learning methods. Vehicle velocity and engine RPM were chosen as the explanatory variables for CO2 prediction. The validation of the model indicates its good precision, while its use is possible for the analysis of continuous CO2 emissions and the creation of emission maps for environmental analyses in urban areas. The validation coefficients for the selected gradient-boosting method of modelling CO2 emissions for an LPG vehicle are the R2 test of 0.61 and the MSE test of 0.77.

Effect of laser irradiation on RF-sputtered antimony sulfide thin films

One of the drawbacks of Sb2S3 thin films is the lack of crystallinity if no thermal treatment is applied. The interest for the development of crystallinity is to improve their properties. Thus, laser irradiation could provide sufficient energy to improve the crystallinity in the above-indicated material. In this work, Radio Frequency (RF)-sputtered Sb2S3 thin films were irradiated with a continuous CO2 laser. Laser treated samples showed crystallization corresponding to the stibnite phase (Sb2S3). Furthermore, the morphology of the sample changed from a cracked surface (before irradiation) to a more dense/homogeneous film (after irradiation). The structural and morphological changes induced by laser irradiation tend to improve the optical and electrical properties aside the crystalline one. When the sample was treated with laser, an increase in optical and photoconductivity properties were detected. The results presented here demonstrate the possibility of improving the quality of Sb2S3 films when a far-infrared laser is applied.

Research on the Differential Oil Producing in the Various Scale Pores under Different CO2 Flooding Modes with a Fluid Distribution Pore Classification Method

CO2 injection is an effective way to improve oil recovery for tight sandstone reservoirs. In this study, the tight sandstone cores collected from Chang 6 Member of Yanchang Formation in Ordos Basin underwent continuous CO2 flooding, and CO2 huff and puff oil displacement measurements were collected under five various CO2 injection pressures, 4, 8, 12, 16, and 20 MPa respectively; combined with the classification of pores in the tight sandstone cores, the differences in oil producing degree in varying scale of pores were discussed in detail. Under continuous CO2 flooding, the oil producing degree reaches up to 73.29%, while the CO2 huff and puff features a higher oil producing degree, and it reaches almost 82.03%. The oil producing degree for these two modes shows a triple-stage with increasing CO2 injection pressures. There are five types of pores in tight sandstone pores, including I-1, I-2, I-3, I-4, and II, and the I-3 and I-4 pores feature not only a significantly high oil producing degree but also the smallest differences in oil producing degree under the two different CO2 flooding modes. The pore size effect is more significant in the tight sandstone cores with the increase in CO2 injection pressures; in comparison with the continuous CO2 flooding, the difference of oil producing degree in the pores with smaller apertures is significantly higher for the CO2 huff and puff, while it is not obvious in the pores with larger pore apertures, especially when the CO2 injection pressure exceeds the minimum miscible pressure (MMP). In addition, the CO2 injection pressure decreases to obtain the optimal oil producing degree in pores with larger pore aperture. This study can help in selecting appropriate CO2 injection modes to achieve the oil enhanced recovery for various types of tight sandstone reservoirs.

The study of the Resultant of Attenuation in laser Radiance by Humidity Effecting on using two Types of water

This research sheds the light on the effects of one weather factors the humidity which are got from vaporing two rinds of water Tigress water and distilled water so they affect laser beams transmittance and change of humidity ranges. The laser of continuous CO2 with wave length 10.6 µm with power reads 0.8 mw and the laser of He-Ne laser with wave length of 632 nm with power reads 2.04 mw The beams of laser in the cell attenuation and measuring laser by using power sensor 's then using the effect factors after going on 2m. Then transmittance decrease with high humidity . The relation between transmittance ranges for beams of laser and humidity depend on spectrum of water vapor absorption, wave light of lasers, powers of. Therefore the effect of humidity that is got by vaporing water that this process becomes more effective on, the transmittance of laser than using other kinds of water. The reason is that, rivers water contains many melted elements which may vapor through increasing temperature to boiling and eventually it affects transmittance.

Anodic Reaction in Syngas-Fueled Proton-Conducting Solid Oxide Fuel Cells

Anode-supported proton-conducting solid oxide fuel cells (PC-SOFCs) fabricated with two representative proton-conducting oxides, BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb) and BaZr0.8Y0.2O3-δ (BZY), were compared to obtain the insight into the electrochemical performances when fueled with syngas at 700°C and the correlation between the anode thickness (0.4, 0.8, and 1.6 mm) and operational stability. We have demonstrated that, in stability tests, the BCZYYb cells exhibited significantly higher maximum power density (MPD) than the BZY cells when operating on H2, 1.22 and 0.48 W/cm2 for the BCZYYb and BZY cells, but the BCZYYb cells degraded more rapidly than the BZY cells when operating on syngas. In addition, decreasing the anode thickness significantly enhanced the stability of BCZYYb cells operating on syngas, a reduction of 81, 76, and 71% in MPD for 1.6, 0.8, and 0.4 mm anode after 30 min. The electrochemical impedance spectra and X-ray diffraction patterns indicated that the rapid degradation of cerate-based cells with syngas could be mainly attributed to the considerable increase in polarization resistance due to the phase decomposition of the electrolyte powder in the anode. Heterogeneous catalysis was performed to study the catalytic reaction of the H2–CO mixture over anode powders prepared with the two proton-conducting oxides (Ni-BCZYYb and Ni-BZY) in a fixed bed reactor, and the CO conversion and selectivity to CO2 and CH4 were determined. For all anode powders, continuous CO2 production was initially observed with CH4 formation, and no significant difference in catalytic activity trends was observed between both anode powders. An increased residence time substantially decreased the normalized CO2 yield, which was associated with the potential secondary reaction of CO2 with H2, CH4, or perovskite oxide. Based on the results of heterogeneous catalysis with both anode powders, the observed cell degradation on both cells during operation with syngas may be primarily attributed to carbon coking due to CO disproportionation; however, more than 4 times rapid degradation of the cerate-based cell when operating with syngas was clearly demonstrated to be attributed to the decomposition of the electrolyte powder in anode by the resulting CO2 from the catalytic reaction of the H2–CO mixture.