查看更多>>摘要：Green hydrogen is a promising alternative for decarbonization of the economy.Its production is based on electrolysis powered by energy from renewable sources.Modern renewable sources like wind or solar are of an intermittent nature,a fact that poses a challenge to the operation of the electrolyzers.In this work,we present a superstructure-based optimization framework to design hydrogen production processes.The design involves selection of the power sources(wind/sun generators,grid),selection of the type and size of electrolyzer,and selection of energy storage devices(battery,vessels).The case studies include hydrogen production at different scales to allow a discussion on patterns of technology selection strategies and the synergies between them.Overall,our simulations show that solid oxide electrolyzers are a promising option,and that from the currently market available alternatives,alkaline electrolysis is preferred over proton exchange membrane electrolysis.Our results support the idea that complementary of the pattern of the energy sources should be sought,but not the idea of producing hydrogen to take advantage of energy surplus and avoid curtailment.
查看更多>>摘要：Catalytic hydrothermal liquefaction of empty fruit bunch(EFB)with no added H2 effectively produces biomass derived fuel or known as bio-oil.In this study,a bimetallic modified zeolite(BaNi,BaLa and BaCe/CHZSM5)catalyst with a series of dosage ratio(1:1,1:2 and 2:1)was used for the EFB conversion to bio-oil.Ni,La and Ce addition to the Ba/CHZSM5 showed significant changes on the physicochemical properties of catalysts and exhibited enhanced catalytic performance.The activity-structure correlation revealed that EFB conversion and bio-oil yield were favoured on bimetallic modified CHZSM5 and the most effective catalyst was BalLa2/CHZSM5.Brunauer-Emmett-Teller(BET)surface area measurement and temperature programmed desorption of ammonia(TPD-NH3)results confirmed that high surface area and rich acidic sites of BalLa2/CHZSM5 catalyst eventually enhanced the catalytic activity in HTL of EFB.Comparing to other bimetallic modified catalyst,the desirable aromatic and aliphatic hydrocarbon also predominated over BalLa2/CHZSM5 catalysed reaction which demonstrated that this catalyst have a good ability in produce high quality of bio-oil with less oxygenated compounds.
查看更多>>摘要：Electrochemically-driven processes are emerging as competitive solution for environmental remediation.When considering scaling of processes accurate engineering modeling can aid on process engineering design for real application.This work defines step stones on electrochemical reactor engineering understanding and sets guidelines for UV/Electro-Fenton-like process modelling to ease scale-up to pilot plant.The UV/Electro-Fenton-like process considers the use of a flow-by cell with parallel plate electrodes to electrogener-ated in situ active chlorine species.The turbulent convection-diffusion equation was solved for mass transport simulations considering for the first time a simplified kinetic model in recirculation mode of operation to remove a model contaminant.Tertiary current distribution was solved to simulate the electrochemical production of HClO.The theoretical analysis evidences a quasi-uniform current distribution in the working electrode,a continuous consumption of chloride,and sustained production of HClO for effective treatment at larger scale system level.Comparisons between numerical and experimental results evidence high predictability of the designed model that can be effectively translated for other electrochemically-driven processes.
查看更多>>摘要：A fixed bed for adsorption desulfurization(ADS)from a typical diesel fuel is designed via dynamic simulation,taking into account the hindering effects of polyaromatics(PAHs)and nitrogen compounds.Experimental results reveal the order of these compounds in term of adsorption affinity as dibenzothiophene > indole > quinoline > methylnaphthalene > naphthalene.At equimolar concentrations,the inhibitory effect of nitrogen compounds is substantially larger than that of PAHs.The simulations of mul-ticomponent breakthrough curve based on the ideal adsorbed solution theory and the linear driving force model match the experimental data.The mass transfer process is controlled using a combination of liquid film diffusion and pore diffusion.For adsorbate molecules with a critical diameter of approximately 0.7 nm,the mass transfer process possibly occurs from the liquid phase into macro-or mesopores before being adsorbed in micropores.The designed fixed bed for ADS from a typical diesel fuel shows a good negative linear relationship between the liquid hourly space velocity and the ratio of dibenzothiophene to the total adsorption amount(maximum value of 9.82%).
Mohd Hardyianto Vai BahrunAwang BonoNorasikin Othman
22页
查看更多>>摘要：Biogas is considered a future energy,alternative to natural gas due to its high methane content.Different substrate feedstock determines the composition of the produced raw biogases.Upgrading or purifying the raw biogas by removing carbon dioxide and thereby increasing its methane content to produce high purity biomethane is mandatory before delivering for natural gas substitute.At present,the pressure swing adsorption(PSA)plays a vital role in biogas upgrading along with water scrubbing,chemical absorption,and membrane permeation.In PSA,the core system lies in the adsorbent choice,which determine the effectiveness of separation by measuring the adsorbent's adsorptive capacity and selectivity.In fact,the PSA system itself is bound for many configurations that require optimization for better tuning the system.As such,it is imperative to comprehend the parameters affecting the PSA performance,thus optimizing them to achieve the objective functions.The optimization through the design of experiment techniques provides realistic statistical information and is among the simplest PSA optimization strategies.Owing to the attractiveness of PSA in many gas separation applications from historical and practical evidences,it is expected that this technology will become more competitive for biogas upgrading
查看更多>>摘要：This work explored an industrial-scale cocoa liquor pressing process used to obtain two standard fat-reduced cocoa powders with 12% and 16% wt.fat,respectively.A novel methodology was developed to sample and characterize fat content in cocoa cakes as released from the press before the powdering.Cocoa liquors with ~ 53% wt.fat,and with solids containing maximum ~1% wt.of particle below mesh 200 were pressed at 90 ℃,and up to 550 bar following a specific time-pressure profile.Fat content in samples was measured with a pulsed nuclear magnetic resonance spectrometer.Experiments enabled to evaluate the variability of fat content of products from different batches,in different cakes from a batch,and within the cakes,verifying large average deviations(~ 5% wt.).By using a Kernel canonical correlation analysis with a Kriging interpolation approach,it was possible to map the fat content profile within the cakes,enabling to identify suitable sampling areas in the cakes for consistent and more accurate measurements of fat content in the product.Finally,the developed methodology was used to characterize different pressing batches at the industrial facility,and to correlate the required processing time for a specific fat content in the liquor.
Mohammad Hossein SadeghiHamid Reza MortahebKourosh Tahar Heidar
13页
查看更多>>摘要：Polyvinyl alcohol)(PVA)/polyethersulfone(PES)composite membranes were fabricated using two PVA polymers with molecular weights of 50,000 and 15,000 and different crosslinker agents.The membrane with the top layer consisting PVA 50,000 and formaldehyde as the crosslinker were found to have a better separation factor than the others for pervaporative dehydration of isopropanol.While adding 1.0 wt% graphene oxide could represent a better pervaporation separation factor,248.7% higher than that of the unfilled membrane,treating the graphene oxide nanosheets using cold plasma irradiation under oxygen atmosphere could yield 47.5% higher separation factor compared to the membrane containing untreated nanosheets owing to higher functional groups on the treated nanosheets that enhance the crosslinking density of the membrane.The best plasma treatment conditions in the selected range were found as 60 s irradiation under 0.3 mbar pressure and device power of 25 watts.The superior performance of the optimal membrane fabricated in the present study was confirmed by comparing the values of normalized pervaporation water index with those in previous studies.
查看更多>>摘要：The Selective Non-Catalytic Reduction process was investigated through experiments and modelling in a bench scale cyclone reactor.Outlet and internal profiles of NO and NH3 concentrations were measured at varying operating conditions.Cyclone inlet temperatures between 866 and ~1O_23 ℃ were used,while the inlet NO concentration was kept at ~500 ppm.Gaseous ammonia was injected in the cyclone inlet,with nitrogen carrier gas.60-69% NO reduction was achieved at inlet temperatures of 975-982 ℃,and stoichiometric ratio NH3/NO β ≈ 1.6,with no ammonia slip.The main reaction zone was the inlet and upper cyclone chamber.The experiments was modelled using simple and detailed kinetics combined with simple reactor models and a compartment model suggested in this work.The qualitative trends of NO reduction and ammonia slip were predicted by the models.However,the ammonia slip was significantly over-predicted in most cases.The outlet concentrations were insensitive to choice of reactor model,while sensitive to temperature and kinetics.The compartment model quantitatively reproduced the cyclones NO concentration profiles,through its simplified representation of the cyclone flow and temperature gradients,while the NH3 profiles were only qualitatively predicted.The choice of bypass fractions showed a large influence on the ammonia profiles.
查看更多>>摘要：Decolorizations,degradation and mineralization of wastewater containing dyes utilizing an electrocatalytic membrane reactor(ECMR)is a beneficial development to conventional advanced oxidation processes(AOPs)caused of its robust efficiency and sustainability and environmental appropriateness.We herein developed a stainless-steel mesh(SSM)electrode supported a porous membrane via incorporation of a PVDF casting solution containing CuFeO2 delafossite nanoparticles impregnated in nanoporous carbon(NPG)biomass derived from apple powder as a critical electrocatalytic and chemical confinement active sites.The SSM membrane electrode was applied as the anode in a gravity-driven ECMR with deep-permeation and self-cleaning function and its concept-of-proof were investigated by methyl orange(MO,as typical azo dyes)electrocatalytic oxidation/filtration.As-designed system exhibiting a robust degradation efficiency of over 98.72% toward MO due to the heterointerfacial structure of CuFeO2 and NPC,which provided the fast electron transfer and low recombination rate,the superior generation rate of the hydroxyl radicals,large effective surface area,self-regenerability,and the least fouling and concentration polarization.The TOC and COD analysis validated that the treatment by as-prepared ECM is proficient for effluent-treatment than the industrial physico-chemical treatments.This strategy beacon paves the headlight for the substantial understanding and designing of novel extremely effective and economic ECMs for several potential applications,including environmental remediation.
查看更多>>摘要：Given that the common constant frequency pulse electric field cannot meet the requirements of the optimal demulsification frequency change in the demulsification process,a chaotic pulse group(CPG)electric field with chaotic group frequency,constant field intensity and group pulse number is proposed to excite all droplets in oil to resonate and improve the demulsification efficiency.However,the vibration and deformation characteristics of droplet in emulsion oil under the CPG electric field is unclear.Therefore,the droplet deformation dynamic model under the CPG electric field is established by applying the finite element method.The influences of duty cycle and group pulse number on droplet deformation are analyzed,and the mechanism of droplet relaxation in CPG electric field is investigated.Results show that the optimal duty cycle is _(0.5)and the optimal group pulse number is 3.The droplet tends to be resonant when the frequency of the electric field group is close to its resonant frequency,and its steady vibration mainly depends on the consistency of the state of the droplet after the end of the latter pulse with that of the former pulse.
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