scholarly journals Dynamic Adsorption of Nitric Oxide (NO) in a Fixed-bed Reactor Using Rubber Seed Shell-derived Biochar

2021 ◽  
Vol 12 (2) ◽  
pp. 1638-1650
Keyword(s):  
Nitric Oxide ◽  
Adsorption Capacity ◽  
Gas Flow ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Alkali Activation ◽  
Feed Concentration ◽  
No Adsorption ◽  
Rubber Seed ◽  
Activated Biochar

Control of nitric oxide emission (NO) as the main constituent of nitrogen oxides (NOx) from combustion sources is a global concern. In this context, this study investigates the adsorption of NO using some biomass-derived adsorbents. Rubber seed shell (RSS) was used as a lignocellulosic residue to develop biochar, modified by metal-doping and alkali activation. The prepared adsorbents, namely, pristine biochar, cerium-loaded biochar and KOH-activated biochar, were used to capture NO in a dynamic fixed-bed adsorption system. The effect of different initial NO feed concentrations (200 and 350 ppm), total gas flow rates (100, 150 and 200 ml/min), and adsorption temperatures (30, 70 and 110 oC) on the adsorption capacity of the adsorbents was investigated. The most suitable operating condition for NO adsorption was found to be the NO feed concentration of 200 ppm, inlet gas flow rate of 100 ml/min and the adsorption temperature of 30 oC at which the high NO adsorption capacity of 81.67, 142.53 and 470.50 mg/g was attained for pristine, Ce-loaded, and KOH-activated biochars, respectively. The adsorbents showed high sustainability in the regeneration process within 5 cycles of NO adsorption-desorption. These results highlight the high potential of RSS-derived biochar for the control of NOx emission from flue gases.

Removal of NOx by Cement Raw Meal and Biochar Admixture

2017 ◽  
Vol 898 ◽  
pp. 1880-1884 ◽  
Author(s):  
Bin Wang ◽  
Hong Xia Guo ◽  
Su Ping Cui ◽  
Ya Li Wang ◽  
Xiao Yu Ma ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Active Carbon ◽  
Gas Flow ◽  
No Reduction ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Rate Study ◽  
Reduction Effect ◽  
Loading Amount

Many studies have indicated that carbon can be reduced to nitric oxide. This paper reports an experimental study of NO reduction by mixed materials of biochar or active carbon with cement raw meal. The proportion of mixed materials was 95 wt.% cement raw meal and 5 wt.% biochar or active carbon. A mixture loading amount and gas flow rate study quantifying the effect of carbon amount and gas residence on the reduction of nitric oxide was carried out. The experiment was performed in a fixed bed reactor at the temperature of 800°C, with O2 concentration of 1%. The inlet NO concentration was 1000 ppm. The characterization of structure and properties of biochar and active carbon was conducted by SEM-EDS, BET. The results show that different carbon materials have different NO reduction effect. The NO conversion rate increases with the increase of the amount of mixture loading. This method of removing NO is practically feasible.

scholarly journals Thermochemical Heat Storage in a Lab-Scale Indirectly Operated CaO/Ca(OH)2 Reactor—Numerical Modeling and Model Validation through Inverse Parameter Estimation

2021 ◽  
Vol 11 (2) ◽  
pp. 682
Author(s):  
Gabriele Seitz ◽  
Farid Mohammadi ◽  
Holger Class
Keyword(s):  
Numerical Model ◽  
Gas Flow ◽  
Reaction Rate ◽  
Heat Storage ◽  
Bulk Material ◽  
Fixed Bed ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Thermochemical Heat Storage ◽  
Speed Up

Calcium oxide/Calcium hydroxide can be utilized as a reaction system for thermochemical heat storage. It features a high storage capacity, is cheap, and does not involve major environmental concerns. Operationally, different fixed-bed reactor concepts can be distinguished; direct reactor are characterized by gas flow through the reactive bulk material, while in indirect reactors, the heat-carrying gas flow is separated from the bulk material. This study puts a focus on the indirectly operated fixed-bed reactor setup. The fluxes of the reaction fluid and the heat-carrying flow are decoupled in order to overcome limitations due to heat conduction in the reactive bulk material. The fixed bed represents a porous medium where Darcy-type flow conditions can be assumed. Here, a numerical model for such a reactor concept is presented, which has been implemented in the software DuMux. An attempt to calibrate and validate it with experimental results from the literature is discussed in detail. This allows for the identification of a deficient insulation of the experimental setup. Accordingly, heat-loss mechanisms are included in the model. However, it can be shown that heat losses alone are not sufficient to explain the experimental results. It is evident that another effect plays a role here. Using Bayesian inference, this effect is identified as the reaction rate decreasing with progressing conversion of reactive material. The calibrated model reveals that more heat is lost over the reactor surface than transported in the heat transfer channel, which causes a considerable speed-up of the discharge reaction. An observed deceleration of the reaction rate at progressed conversion is attributed to the presence of agglomerates of the bulk material in the fixed bed. This retardation is represented phenomenologically by mofifying the reaction kinetics. After the calibration, the model is validated with a second set of experimental results. To speed up the calculations for the calibration, the numerical model is replaced by a surrogate model based on Polynomial Chaos Expansion and Principal Component Analysis.

Removal of VOCs Using Sludge-Based Adsorbents

2012 ◽  
Vol 599 ◽  
pp. 305-308 ◽  
Author(s):  
Ping Fang ◽  
Chao Ping Cen ◽  
Hong Tao Zhang ◽  
Zi Jun Tang ◽  
Ding Sheng Chen ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Physical Adsorption ◽  
Low Cost ◽  
Fixed Bed ◽  
Cost Effective ◽  
Langmuir Adsorption Isotherm ◽  
Fixed Bed Reactor ◽  
Dynamic Adsorption ◽  
Langmuir Adsorption ◽  
Isotherm Equations

Efficient and cost-effective sludge-based adsorbents were developed and the adsorption of VOCs on the sludge-based adsorbents was studied in a fixed bed reactor. The results indicate that the adsorption of VOCs on sludge-based adsorbents is typical physical adsorption, the dynamic adsorption capacity of VOCs on adsorbents sharply increases as the VOCs concentration is increased at first, then increasing gradually, at last retains stable with the change of VOCs concentration. The dynamic adsorption capacity of sludge-based adsorbents for VOCs is O-Xylene > Butylcetate > Toluene > Ethylacetate > Benzene > Propanone > n-Hexane, the maximum dynamic adsorption capacity is 0.247, 0.225, 0.192, 0.186, 0.180, 0.176, 0.133g/g, respectively. Meanwhile the adsorption of VOCs on sludge-based adsorbents corresponds to the Langmuir adsorption isotherm equations. The sludge-based adsorbent is a low-cost alternative to activated carbon for VOCs treatment, and this technology is a promising method for the VOCs removal.

Bio-oil production from fast pyrolysis of maple fruit (acer platanoides samaras): product yields

2017 ◽  
Vol 14 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Ali Bahadir ◽  
Turgay Kar ◽  
Sedat Keles ◽  
Kamil Kaygusuz
Keyword(s):  
Gas Flow ◽  
Fast Pyrolysis ◽  
Fixed Bed ◽  
Pyrolysis Product ◽  
Fixed Bed Reactor ◽  
Energy Sources ◽  
Potential Candidate ◽  
Content Type ◽  
Product Yields ◽  
Bio Oil

Purpose The purpose of this paper is to investigate fast pyrolysis of maple fruit as an energy sources. This could serve as a solution to the energy sources problem. Design/methodology/approach Fast pyrolysis of maple fruit (samara) was achieved in a fixed bed reactor. The pyrolysis experiments have been conducted on the sample of maple seeds to particularly determine the effects of pyrolysis temperature, particle size and sweep gas flow rate on the pyrolysis product yields. Findings The oil of maple fruit from fast pyrolysis has good properties to be a potential candidate as a biofuel or as a source of chemicals. In addition to being environmentally desirable, it can reduce the energy cost, e.g. that Turkey imports a majority of its energy. Originality/value The use of maple fruit for fast pyrolysis and pyrolysis conditions impact on the yields of pyrolysis liquid can be considered as novel aspects of this paper.

Effect of Fractal Dimension of Powder Activated Carbon on SO2 Adsorption

2014 ◽  
Vol 955-959 ◽  
pp. 2169-2172 ◽  
Author(s):  
Bing Li ◽  
Jian Ming Xue ◽  
Yue Yang Xu ◽  
Hong Liang Wang ◽  
Chun Yuan Ma ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Activated Carbon ◽  
Adsorption Capacity ◽  
Activated Carbons ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Removal Capacity ◽  
Powder Activated Carbon

Five kinds of powder activatedcarbons were studied to investigate the removal of SO2 from flue gasin a fixed bed reactor. The fractal dimension of activated carbon was determined by N2 adsorption isothermat 77Kand SO2 adsorptioncapacity was correlated with thefractal dimension. The results show thatthe activated carbons prepared from different precursors by differentactivation methods have different fractal dimension. Big differences in SO2 adsorption capacity are found between fivekinds of activated carbons. SO2 adsorption capacity increases with the fractaldimension increasing. The results indicate that the fractal dimension could be used as a indicator of SO2removal capacity on powder activated carbon.

Zinc(II) desorption by Sargassum filipendula biomass in batch and in fixed-bed column for multiple sorption-regeneration cycles

2009 ◽  
Vol 60 (2) ◽  
pp. 357-362 ◽  
Author(s):  
Araceli A. Seolatto ◽  
Maurício M. Câmara ◽  
Eneida S. Cossich ◽  
Célia R. G. Tavares ◽  
Edson A. Silva
Keyword(s):  
Adsorption Capacity ◽  
Flow Rate ◽  
Batch Reactor ◽  
Fixed Bed ◽  
Feed Concentration ◽  
Fixed Bed Column ◽  
Batch System ◽  
High Efficient ◽  
Sargassum Filipendula

The reusability of the alga Sargassum filipendula was studied in batch reactor and in fixed-bed column in order to investigate Zn(II)-laden biomass regeneration. Four types of desorbing solutions at two different concentrations were tested and the results obtained to the desorption efficiencies were higher than 90% for three of the agents. Ten consecutive sorption-regeneration cycles at a flow rate of 8 mL/min were carried in fixed bed column with the feed concentration of 50 mg/L and using two eluent solutions: H2SO4 (0.1 M) and MgSO4 (3.5% at pH 3), which showed the best ability to elution tests in batch system. The column was used for a period of 30 days. The adsorption capacity decreased the passing of cycles, but the total amount of zinc removed after 10 cycles was approximately 8 times greater than if the biomass had been used for only one time, for both agents tested. Therefore, the regeneration in the Sargassum filipendula column through the two desorbing agents tested showing high efficient use of biomass and facilitating the process of treatment of wastewater containing metals that has successive exchanges of biomass.

scholarly journals Modelling of NO adsorption in fixed bed on activated carbon

2011 ◽  
Vol 32 (4) ◽  
pp. 367-377 ◽  
Author(s):  
Lenka Kuboňová ◽  
Lucie Obalová ◽  
Oldřich Vlach ◽  
Ivana Troppová ◽  
Jaroslav Kalousek
Keyword(s):  
Nitric Oxide ◽  
Mass Transfer ◽  
Activated Carbon ◽  
Fixed Bed ◽  
Breakthrough Curves ◽  
Force Model ◽  
Transfer Coefficients ◽  
No Adsorption ◽  
Response Curves ◽  
Mass Transfer Mechanism

Modelling of NO adsorption in fixed bed on activated carbon Adsorption experiments of nitric oxide in nitrogen carrier gas were held on activated carbon in a fixed bed flow system. Breakthrough curves describing the dependence of exit concentrations of nitric oxide on time were matched with theoretical response curves calculated from the linear driving force model (LDF). The model assumes Langmuir adsorption isotherm for the description of non-linear equilibrium and overall mass transfer coefficient for mass transfer mechanism. Overall mass transfer coefficients were obtained by the method of least squares for fitting numerically modelled breakthrough curves with experimental breakthrough curves. It was found that LDF model fits all the breakthrough curves and it is a useful tool for modelling purposes.

Synthesis of NaY Zeolite and their CO2 Adsorption Properties

2014 ◽  
Vol 1033-1034 ◽  
pp. 399-403
Author(s):  
Ren Juan Ma ◽  
Yong Quan Xu ◽  
Yu Min Liu ◽  
Rui Hong Zhao ◽  
Xiang Jing Zhang ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Gas Flow ◽  
Separation Efficiency ◽  
Sol Gel ◽  
Fixed Bed ◽  
Nay Zeolite ◽  
Sol Gel Process ◽  
Curve Method ◽  
Ft Ir ◽  
Adsorption Desorption

NaY zeolite was prepared by a simple sol-gel process. The prepared NaY was characterized by XRD,FT-IR,N2adsorption/desorption isotherms, and scanning electron microscope (SEM). The CO2dynamic adsorption/desorption performance of NaY was tested under atmospheric pressure using adsorption curve method in the fixed bed. The results demonstrate that NaY offeres high separation efficiency for CO2against N2. To further identify the most adsorption conditions, different adsorption temperatures and gas flow rates were investigated respectively. It is shown that NaY zeolite has the largest adsorption capacity of 88 mg/g adsorbent at 60°C,50ml/min, and the sample maintains still strong adsorption capacity and stable structure during 6 consecutive test cycles, which exhibits its stable adsorption/desorption behavior.

scholarly journals Gas-phase elemental mercury removal by nano-ceramic material

2020 ◽  
Vol 10 ◽  
pp. 184798041989975
Author(s):  
Tao Zhu ◽  
Weidong Jing ◽  
Xing Zhang ◽  
Wenjing Bian ◽  
Yiwei Han ◽  
...  
Keyword(s):  
Gas Phase ◽  
Gas Flow ◽  
Removal Rate ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Mercury Removal ◽  
Bet Surface Area ◽  
Mercury Adsorption ◽  
Experimental Conditions ◽  
Physical And Chemical

The nano-ceramic which is mesoporous silica material was applied to test the removal efficiency of gas-phase Hg0 using a fixed-bed reactor. The physical and chemical properties of nano-ceramic were investigated by various techniques such as BET surface area (BET), X-ray diffraction, fourier transform infrared spectrometer (FTIR), and scanning electron microscope (SEM); then, the sample was tested for mercury adsorption under different conditions. The mercury adsorption tests shown that different Hg0 concentration, adsorption temperature, gas flow rate, and different gas components have significant effects on the mercury removal performance of nano-ceramic, and the adsorption removal rate of nano-ceramic can be 75.58% under the optimal experimental conditions. After fitting the experimental data to the adsorption model, it was found that the theoretical maximum mercury adsorption amount q max of nano-ceramic is 1.61 mg g−1 and there were physical and chemical adsorption at the same time. The adsorption kinetics fitting results shown that the adsorption process of nano-ceramic exhibits multi-segment characteristics of “transmembrane–diffusion–adsorption.”

scholarly journals Catalytic combustion of isopropanol over Co–ZSM-5 zeolite membrane catalysts in structured fixed-bed reactor

2018 ◽  
Vol 5 (8) ◽  
pp. 180587 ◽  
Author(s):  
Xiaotong Zhang ◽  
Ying Yan
Keyword(s):  
Catalytic Combustion ◽  
Secondary Growth ◽  
Fixed Bed ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Zeolite Membrane ◽  
Fixed Bed Reactor ◽  
Impregnation Method ◽  
Feed Concentration ◽  
Growth Method

Catalytic combustion of isopropanol in the structured fixed-bed reactor was investigated over Co–ZSM-5 zeolite membrane catalysts. Firstly, ZSM-5 zeolite membrane catalysts with different Si/Al ratios were coated onto the surface of stainless steel fibres via secondary growth method and wet lay-up paper-making method. Then, cobalt oxides were loaded onto the zeolite membranes by impregnation method. The performance of catalytic combustion of isopropanol was conducted over the prepared zeolite membrane catalysts, and the experimental results showed that the catalyst with infinite Si/Al ratio has the highest catalytic activity for the combustion with the lowest T 90 of isopropanol (285°C). Finally, the effects of bed structure, feed concentration, gas hourly space velocity and reaction temperature on the catalytic performance were investigated to analyse the kinetics of isopropanol over the catalyst with infinite Si/Al ratio in the structured fixed-bed reactor. The results showed that the longer residence time could cause higher reaction contact efficiency of isopropanol combustion. T 90 of isopropanol can be dramatically decreased by 105°C in the fixed-bed reactor packed with Co–ZSM-5 zeolite membrane catalysts, compared to the fixed-bed reactor packed with granular catalyst.

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