Sustainable Food and Fuel on Yongxing Island by Conversing the Carbon Captured from Ambient Air

AbstractSynthetic hydrocarbon fuel, derived from renewable energy and captured carbon dioxide from ambient air, can thoroughly close its carbon cycle and is a promising option for CCU and an important approach to sustainable energy. We investigate the Yongxing island in south China sea, which offers steady wind resources to provide continuous energy supply for plant factory and fuel synthesis. The energy consumption of MSAC and TSAC is compared and conversion of the captured CO2 to food and fuel are calculated. Powered by wind energy, 200 ton vegetables and 5.2*103 ton diesel will be produced per year, so self-sufficiency of vegetable and fuel demand can be achieved on Yongxing island. Our methodology could provide a new utilization mode for islands like Yongxing island

Experiments and DFT study on modified CaO-based adsorbents for enhanced CO2_{{2}} capture

CaO-based adsorbents for carbon capture represent a promising technology for reducing carbon emission. In this study, we prepare metal oxide-doped multifarious CaO-based adsorbents using the hydration method. We investigate the effect of various working conditions, such as temperature and carbonation time, on different adsorbents in a fixed-bed reactor under multiple carbonation–calcination cycles. We examine the behavior of different metal oxides-doped synthetic adsorbents using density functional theory calculation based on experiments. The results prove that 5 wt% ZrO2-doped adsorbents show excellent CO2 adsorption efficiency, which reaches up to 38.4% after 20 carbonation–calcination cycles at 700 °C with 15 vol% CO2. The adsorbents doped with other metal oxides are also useful for CO2 capture to varying degrees. The adsorption energy of CO2 molecules on modifiequationed adsorbents is higher than that on pure CaO, especially for Zr, where the adsorption energy reached 2.37 eV. The calculation results are in good agreement with the experimental data

Hydrodynamics and heat transfer of suspended surface in a supercritical cfb furnace

With the scaling-up of CFB boilers, more heating surfaces like suspended surfaces and/or mid-partition walls, are arranged in the furnace to ensure adequate heat absorption. The length of suspended surface reaches almost half height of the furnace in the Baima 600MW supercritical CFB boiler. Since the gas-solids hydrodynamics and heat transfer on those surfaces are different from that on waterwall, further researches are needed to investigate the characteristics of hydrodynamics and heat transfer on the suspended surfaces. Beside the experimental measurements on the suspended surfaces in a scale down test rig, the hydrodynamic characteristics on the suspended surfaces were computed by a CFD simulation combined with EMMS model in a supercritical CFB of annular furnace. The results present an uneven axial solid concentration profile on the suspended surface, and descending particles are found on some locations especially where those surfaces far away from the furnace exits. Based on the gas-solids hydrodynamic results, the modified cluster renewal model was applied in the heat transfer coefficient calculation of the suspended surfaces. The result shows the heat transfer coefficient varies with the height and it has difference between two sides of a surface. In addition, the average heat transfer coefficients of suspended surface at different locations are compared. References Basu P, Nag P K. Heat transfer to walls of a circulating fluidized-bed furnace[J]. Chemical Engineering Science, 1996, 51(1): 1-26. Cen K F, Ni M J, Luo Z Y, et al. Theoretical design and operation of circulating fluidized bed boiler[J]. China Electric Power Press, Beijing, 1998: 647-663. Cheng L M, Wang Q H, Shi Z L, et al. Heat transfer in a large circulating fluidized bed boiler[J]. Journal of Power Engineering, 2006, 26(3): 305-310. Huang C, Cheng L M, Zhou X L, et al. Suspended surface heat transfer in a large circulating fluidized bed boiler furnace[J]. Journal of Zhejiang University. Engineering Science, 2012, 46(11): 2128-2132. Sundaresan R, Kolar A K. Axial heat transfer correlations in a circulating fluidized bed riser[J]. Applied Thermal Engineering, 2012. * “Strategic Priority Research Program” of the Chinese Academy of Sciences, Grant No. XDA0703010

Numerical Study of the Movement of Fine Particle in Sound Wave Field

AbstractInhalable particulate matter, especially PM2.5 is one of the main pollutants in China and it's harmful to both human health and atmosphere. Since the removal efficiency of traditional dust removal devices such as ESP for PM2.5 is very low, pretreatment becomes necessary before the dust gets into the dust remover. Acoustic agglomeration is one of the pretreatment technologies which uses sound wave with high intensity to make fine particles get agglomerate and grow up, and improves the efficiency of traditional dust removal devices for PM2.5. In sound wave field, fine particles are carried by the medium which in this paper is air, and vibrate with different amplitude because of different particle sizes, thus relative movement appears and then particles have more chances to collide and get agglomerate. In this paper, the movement of particles with different sizes in travelling wave sound field and standing wave sound field were calculated, including the velocity, displacement, amplitude and so on. The situation that Re<1 was considered and Viscous force in Stokes region was chose as the main forces here. Studying the movement of fine particle in sound field with different conditions has great meaning in learning the mechanisms of acoustic agglomeration

Experiments and DFT study on modified CaO-based adsorbents for enhanced CO2_{{2}} capture

CaO-based adsorbents for carbon capture represent a promising technology for reducing carbon emission. In this study, we prepare metal oxide-doped multifarious CaO-based adsorbents using the hydration method. We investigate the effect of various working conditions, such as temperature and carbonation time, on different adsorbents in a fixed-bed reactor under multiple carbonation–calcination cycles. We examine the behavior of different metal oxides-doped synthetic adsorbents using density functional theory calculation based on experiments. The results prove that 5 wt% ZrO2-doped adsorbents show excellent CO2 adsorption efficiency, which reaches up to 38.4% after 20 carbonation–calcination cycles at 700 °C with 15 vol% CO2. The adsorbents doped with other metal oxides are also useful for CO2 capture to varying degrees. The adsorption energy of CO2 molecules on modifiequationed adsorbents is higher than that on pure CaO, especially for Zr, where the adsorption energy reached 2.37 eV. The calculation results are in good agreement with the experimental data

Life-cycle assessment of emerging CO2 mineral carbonation-cured concrete blocks: Comparative analysis of CO2 reduction potential and optimization of environmental impacts

CO2 mineral carbonation (MC) curing technology provides a promising solution for large-scale CO2 utilization and construction sectors towards low-carbon and environmentally friendly production of concrete, but studies on the total environmental impacts of this technology are scarce. Accordingly, this paper evaluated the life cycle environmental impacts of seven promising concrete blocks from CO2 MC curing manufacturing pathways (Ordinary-Portland cement block, MgO-Portland cement block, wollastonite-Portland cement block, limestone-Portland cement block, calcium silicate cement block, slag-Portland cement block and Waste Concrete Aggregate block), offering detailed results of cradle-to-gate life cycle assessment and inventory. Identification of the contributions of subdivided raw materials and manufacturing processes, as well as the energy consumption, transportation, and upstream processes for raw materials was performed. It was shown that 292–454 kg CO2-eq global warming potential (GWP) of 1 m3 CO2-cured non-hollow concrete blocks were obtained. By contrast, results indicated the 419 kg CO2-eq GWP from a base case of conventional (steam-cured, non MC) Ordinary-Portland cement block. Up to 30% of CO2 emission avoidance could be achieved when replacing steam curing by MC curing and adjusting the binder types. From the point of view of materials and manufacturing, the reduced use of Portland cement is a key step for environmental optimization, while reducing the energy consumption for maintaining high-pressure carbonation helps to cut down the cumulative energy demand. Increasing the blending ratio in binary binders and the lightweight redesign also proved to be beneficial solutions for mitigating environmental impacts of CO2-cured concrete blocks. Wollastonite-Portland cement block and slag-Portland cement block using natural wollastonite and blast furnace slag in binary binders obtained the most favorably scores in all impact assessment indicators, and thus, are arguably considered as the most sustainable types of concrete blocks

Dual Supramolecular Nanoparticle Vectors Enable CRISPR/Cas9-Mediated Knockin of Retinoschisin 1 Gene-A Potential Nonviral Therapeutic Solution for X-Linked Juvenile Retinoschisis.

The homology-independent targeted integration (HITI) strategy enables effective CRISPR/Cas9-mediated knockin of therapeutic genes in nondividing cells in vivo, promising general therapeutic solutions for treating genetic diseases like X-linked juvenile retinoschisis. Herein, supramolecular nanoparticle (SMNP) vectors are used for codelivery of two DNA plasmids-CRISPR-Cas9 genome-editing system and a therapeutic gene, Retinoschisin 1 (RS1)-enabling clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR/Cas9) knockin of the RS1 gene with HITI. Through small-scale combinatorial screenings, two SMNP vectors, with Cas9 and single guide RNA (sgRNA)-plasmid in one and Donor-RS1 and green fluorescent protein (GFP)-plasmid in the other, with optimal delivery performances are identified. These SMNP vectors are then employed for CRISPR/Cas9 knockin of RS1/GFP genes into the mouse Rosa26 safe-harbor site in vitro and in vivo. The in vivo study involves intravitreally injecting the two SMNP vectors into the mouse eyes, followed by repeated ocular imaging by fundus camera and optical coherence tomography, and pathological and molecular analyses of the harvested retina tissues. Mice ocular organs retain their anatomical integrity, a single-copy 3.0-kb RS1/GFP gene is precisely integrated into the Rosa26 site in the retinas, and the integrated RS1/GFP gene is expressed in the retinas, demonstrating CRISPR/Cas9 knockin of RS1/GFP gene

The Influences of Acoustic and Pulsed Corona Discharge Coupling Field on Agglomeration of Monodisperse Fine Particles

In view of the low efficiency of traditional electrostatic precipitators in removing fine particles, acoustic and pulsed corona discharge coupling fields were proposed to increase particle size. In this paper, monodisperse particles with three different sizes (0.5 &mu;m, 2 &mu;m, and 4 &mu;m) were generated to investigate the agglomeration effect under different parameters in external fields. A larger reduction ratio of particle number concentration resulted in a higher agglomeration efficiency. Results indicated that, in the range from 800 to 2400 Hz, the acoustic agglomeration effect on 4-&mu;m particles was better than that on 0.5-&mu;m and 2-&mu;m particles. In the pulsed corona discharge field, agglomeration efficiencies of the three particle sizes were lower than those in the acoustic field. However, application of the coupling field highly improved agglomeration efficiency compared with the single field. When a pulse input voltage of 50 kV with acoustic sound pressure level (SPL) of 143 dB and frequency of 1600 Hz was selected, the corresponding number reduction ratio of 0.5-&mu;m, 2-&mu;m, and 4-&mu;m particles increased to 0.464, 0.526, and 0.918 from 0.254, 0.438, and 0.814 in the acoustic wave field and 0.226, 0.385, and 0.794 in the pulsed corona discharge field

Effect of sarcosinate on the absorption kinetics of CO₂ into aqueous ammonia solution

Promoted aqueous ammonia is a potential solvent for CO₂ separation processes. In this work, we investigated the effect of temperature, sarcosinate concentration, and CO₂ loading on the mass transfer coefficients of CO₂ absorption in a sarcosinate-promoted aqueous ammonia solution on a wetted-wall column. We further investigated the kinetics of the reaction between CO₂ and a blended NH₃/sarcosinate absorbent using stopped-flow spectrophotometric techniques, following the pH changes via coupling to pH indicators. Our study revealed that the mass transfer coefficient for CO₂ absorption in a 3 M ammonia + 1.5 M sarcosinate blended solution at 288 K is close to that in 5 M monoethanolamine absorbent at 313 K. We did not observe any synergistic or catalytic effects between NH₃ and sarcosinate in the blended solution; the mechanism of the reaction of CO₂ with the NH3/sarcosinate mixture is the simple combination of the individual reactions of NH₃ and sarcosinate with CO₂

Numerical Simulation Study on the Gas–Solid Flow Characteristics of a Large-Scale Dual Fluidized Bed Reactor: Verification and Extension

Dual fluidized bed (DFB) reactor systems are widely used in gas–solid two-phase flow applications, whose gas–solid flow characteristics have a significant effect on the performance of many kinds of technologies. A numerical simulation model was established on the basis of a large-scale DFB reactor with a maximum height of 21.6 m, and numerical simulations focused on gas–solid flow characteristics were carried out. The effects of the superficial gas velocity of both beds and the static bed height and particle size on the distribution of the pressure and solid suspension density and the solid circulation rate were studied. The simulation results were in good agreement with the experimental data. With the strong support of the experimental data, the gas–solid flow characteristics of large-scale DFB reactors were innovatively evaluated in this numerical simulation study, which effectively makes up for the shortcomings of the current research. The results showed that the superficial gas velocity of both beds and the static bed height have different degrees of influence on the gas–solid flow characteristics. Specifically, for 282 μm particles, when the superficial gas velocity of both beds and the static bed height were 4.5 m/s, 2.5 m/s, and 0.65 m, respectively, under typical working conditions, the bottom pressure of the two furnaces was 3412.42 Pa and 2812.86 Pa, respectively, and the solid suspension density was 409.44 kg/m3 and 427.89 kg/m3, respectively. Based on the simulation results, the empirical formulas of the solid circulation rate were fitted according to different particle sizes. Under similar conditions, the solid circulation rates of particles with a particle size of 100 μm, 282 μm, 641 μm, and 1000 μm were 2.84–13.28, 0.73–4.91, 0.024–0.216, and 0.0026–0.0095 kg/(m2s), respectively. It can be found that the influence of the particle size on the solid circulation rate is the most significant among all parameters