Population dynamics in an aerobic submerged fixed bed reactor (ASFBR) process

2002 ◽  
Vol 46 (1-2) ◽  
pp. 257-260 ◽  
Author(s):  
I. Lorda-de-los-Ríos ◽  
E. Bécares-Mantecón ◽  
I. Tejero-Monzón
Keyword(s):  
Population Dynamics ◽  
Oxygen Concentration ◽  
Fixed Bed ◽  
High Load ◽  
Fixed Bed Reactor ◽  
Synthetic Wastewater ◽  
Organic Load ◽  
Experimental Conditions ◽  
Low Load ◽  
Aeration Conditions

In this study, an aerobic submerged fixed bed reactor's (ASFBR) population dynamics has been studied in order to know its behavior in different conditions of organic load and oxygen concentration. The reactor was fed with synthetic wastewater. Tested variables and applied values were: 1) Variations in organic load (OL): 16–65 g COD/m2/d. 2) Variations in influent's COD concentration: 40–400 g COD/m3. 3) Variations in specific air flow (SAF): 15–127 m3air/kgCOD. Biofilm samples were taken at the top of the reactor. This study showed important variations in the composition and abundance of the microfauna depending on the experimental conditions. Variations in influent concentration had no significant effect on the abundance of the studied groups. However, differences depending on organic load and aeration conditions were observed. Organic load influenced every group studied but with different results. Sessile cilliates, metazoa and flagellates were abundant in low load, while crawling ones were in high load. Aeration intensity influenced most of the groups except Peranema and Vorticella spp. Despite obtaining good yields, not many protozoa, typical of biofilms under conventional processes, were found. Thus, a great variety of microorganisms, such as many classes of sessile and crawling cilliates, were not found. Important nitrifying activity was obtained at 20 cm depth in a bed. From this point, the heterotrophic and nitrifying populations exist but are inactive.

scholarly journals The Effect of Pyrolysis Temperature on Copyrolysis of Lignite and Pistachio Seed in a Fixed-bed Reactor

2021 ◽  
Vol 15 ◽  
pp. 49-52
Author(s):  
Özlem Onay
Keyword(s):  
Elemental Analysis ◽  
Pyrolysis Temperature ◽  
Fixed Bed ◽  
Product Distribution ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Oil Yield ◽  
Pyrolysis Oil ◽  
Nitrogen Gas ◽  
Experimental Conditions

Co-pyrolysis of lignite and pistachio seed (CPLPS) under nitrogen gas was performed in a Heinze retort. The effect of pyrolysis temperature on product distribution of CPLPS investigated under heating rate of 10°Cmin-1 and blending ratio of 50(wt)%. Biomass is higher yield to be pyrolyzed than lignite and addition of biomass promotes the pyrolysis of lignite. In the range of the experimental conditions investigated the yield of the product is proportional to pyrolysis temperature. On the other hand, considerable synergetic effects were observed during the co-pyrolysis in a fixed bed reactor leading to increase in oil yield. Maximum pyrolysis oil yield of 27.2% was obtained at pyrolysis temperature of 550°C. The obtained oils are characterized by GC, and elemental analysis.

Bioreactor performance and methanogenic population dynamics in a low-temperature (5–18°C) anaerobic fixed-bed reactor

2012 ◽  
Vol 104 ◽  
pp. 136-143 ◽  
Author(s):  
Dongdong Zhang ◽  
Wanbin Zhu ◽  
Can Tang ◽  
Yali Suo ◽  
Lijuan Gao ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Low Temperature ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bioreactor Performance

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 Determination of intraparticle diffusivity and fluid-to-solid mass transfer coefficient from single concentration history curve in circulated-type fixed-bed reactor

2017 ◽  
Vol 36 (1-2) ◽  
pp. 571-585 ◽  
Author(s):  
Noriyoshi Sonetaka ◽  
Yoshimi Seida ◽  
Takuto Nakano ◽  
Eiji Furuya
Keyword(s):  
Analytical Method ◽  
Decay Curve ◽  
Batch Reactor ◽  
Fixed Bed ◽  
Adsorption Kinetic ◽  
Test Method ◽  
Fixed Bed Reactor ◽  
Experimental Conditions ◽  
Reactor Test ◽  
Mixed Batch

In this study, a simple analytical procedure for determining the adsorption kinetic parameters Ds and kF from a single concentration history (decay curve) in circulate-type fixed-bed reactor test method was investigated. A simple and reliable method to obtain the parameters Ds and kF from the decay curve of circulate-type fixed-bed reactor was developed based on an advanced analytical method for the completely mixed batch reactor test method. The experimental conditions in the circulate-type fixed-bed reactor method that meet the application criteria of the advanced analytical method for the completely mixed batch reactor test method were investigated based on the theoretical decay curves of the test methods. Experimental conditions, such as large liquid–solid ratio Zϕ, short contact time z/u, and small bed height Z, which make the decay behaviors in the circulate-type fixed-bed reactor close to those of the completely mixed batch reactor, were evaluated quantitatively on theoretical basis. Furthermore, the reliability of the adsorption kinetic parameters obtained in this study was verified by comparing the kF values with those from a reported empirical correlation equation for kF.

Denitrification Activities of Mg-Mo-V-Ti Catalysts Prepared by Dipping Method at Low Temperature

2018 ◽  
Vol 913 ◽  
pp. 893-899
Author(s):  
Dong Zhu Ma ◽  
Jian Li ◽  
Ling Zhang ◽  
Peng Guo ◽  
Zi Qiang Wen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Selective Catalytic Reduction ◽  
Oxygen Content ◽  
Oxygen Concentration ◽  
Flue Gas ◽  
Catalytic Reduction ◽  
Fixed Bed ◽  
Space Velocity ◽  
Fixed Bed Reactor ◽  
Sulfur Resistance

Mg-Mo-V-Ti catalysts of low temperature denitrification were prepared by dipping method. In order to study the activity of selective catalytic reduction, the catalyst was placed in a fixed bed reactor. Industrial flue gas was simulated with cylinder gas. Results indicate that the 0.1wt% content of MgO catalyst has good performance on denitration activity and sulfur resistance. The effects of oxygen content, space velocity and reaction temperature on the activity of the 0.1MgO-6MoO3-3V2O5-TiO2 wt% catalyst were investigated. With the increase of oxygen concentration, the denitrification efficiency increases when the oxygen concentration is less than 8%. When the oxygen content is greater than 8%, the denitrification efficiency is almost the same. The denitrification efficiency decreases with the increase of space velocity. The removal efficiency of NO 0.1MgO-6MoO3-3V2O5-TiO2 wt% catalyst over increases first and then becomes stable with the increase of temperature, and the conversion efficiency of SO2 is less than or equal to 2.2% at 120~240 °C.

scholarly journals Recycling techniques of polyolefins from plastic wastes

2013 ◽  
Vol 10 (1) ◽  
pp. 114-122 ◽  
Keyword(s):  
Liquid Fraction ◽  
Fixed Bed ◽  
Raw Material ◽  
Fixed Bed Reactor ◽  
Major Type ◽  
Mechanical Recycling ◽  
Experimental Conditions ◽  
Waste Products ◽  
Plastic Wastes ◽  
Recycling Techniques

Disposing of plastic wastes to landfill is becoming undesirable due to legislation pressures, rising costs and the poor biodegradability of commonly used polymers. In addition, incineration meets with strong societal opposition. Therefore, recycling either mechanical or chemical, seems to be the only route of plastic wastes management towards sustainability. Polyolefins, mainly polyethylene (LDPE or HDPE) and polypropylene (PP) are a major type of thermoplastic used throughout the world in a wide variety of applications. In Western Europe alone approximately 22 million tones of these polymers are consumed each year, representing an amount of 56% of the total thermoplastics. In the present investigation the recycling of LDPE, HDPE and PP was examined using two different methods: the dissolution/reprecipitation and pyrolysis. The first belongs to the mechanical recycling techniques while the second to the chemical/feedstock recycling. During the first technique the polymer can be separated and recycled using a solvent/non-solvent system. For this purpose different solvents/non-solvents were examined at different weight percent amounts and temperatures using either model polymers as raw material or commercial waste products (packaging film, bags, pipes and food retail products). At all different experimental conditions and for all samples examined the polymer recovery was always greater than 90%. The quality of the recycled polymer was examined using FTIR and DSC. Furthermore, pyrolysis of LDPE, HDPE and PP was investigated with or without the use of an acid FCC catalyst. Experiments were carried out in a laboratory fixed bed reactor. The gaseous product was analyzed using GC, while the liquid with GC-MS. A small gaseous and a large liquid fraction were obtained from all polymers. Analysis of the derived gases and oils showed that pyrolysis products were hydrocarbons consisting of a series of alkanes and alkenes, with a great potential to be recycled back into the petrochemical industry as a feedstock for the production of new plastics or refined fuels.

An Experimental Study of Steam Gasification of Biomass over Precalcined Copper Slag Catalysts

2013 ◽  
Vol 634-638 ◽  
pp. 479-489 ◽  
Author(s):  
Shuang Hui Deng ◽  
Jian Hang Hu ◽  
Hua Wang ◽  
Juan Qin Li ◽  
Wei Hu
Keyword(s):  
Fixed Bed ◽  
Copper Slag ◽  
Biomass Gasification ◽  
Steam Gasification ◽  
Fixed Bed Reactor ◽  
Hydrogen Yield ◽  
Mass Ratio ◽  
Experimental Conditions ◽  
Gasification Efficiency ◽  
Gasification Temperature

Biomass gasification was separated from catalytic pyrolysis in a two-stage fixed bed reactor with precalcined copper slag catalysts placed in a secondary reactor. The effects of gasification temperature (720-950°C), steam to biomass (S/B) mass ratio (0-2g/g), precalcined copper slag to biomass (C/B) mass ratio (0-2g/g) and copper slag precalcined at different temperatures (800-1000°C) on characteristics of biomass gasification were investigated. The experimental results show that the increase of gasification temperature, S/B mass ratio, C/B mass ratio and precalcination temperature are all favorable for raising gasification efficiency and enhancing the H2 production. With copper slag precalcined at 1000°C for 5 hours as catalyst under the experimental conditions examined, the H2 content, the hydrogen yield, the gas yield and the gasification efficiency reach the maximum of 59.16%, 0.72 Nm3/kg, 1.22 Nm3/kg and 77.56%,respectively.

scholarly journals Hydrogen production from cassava processing wastewater in an anaerobic fixed bed reactor with bamboo as a support material

2015 ◽  
Vol 35 (3) ◽  
pp. 578-587 ◽  
Author(s):  
Cristiane L. Andreani ◽  
Douglas G. B. Torres ◽  
Leonardo Schultz ◽  
Karina Q. de Carvalho ◽  
Simone D. Gomes
Keyword(s):  
Hydrogen Production ◽  
Waste Treatment ◽  
Sugar Content ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Organic Load ◽  
Organic Loading Rate ◽  
Total Sugar Content ◽  
Working Volume ◽  
Production Of Hydrogen

Attempting to associate waste treatment to the production of clean and renewable energy, this research sought to evaluate the biological production of hydrogen using wastewater from the cassava starch treatment industry, generated during the processes of extraction and purification of starch. This experiment was carried out in a continuous anaerobic reactor with a working volume of 3L, with bamboo stems as the support medium. The system was operated at a temperature of 36°C, an initial pH of 6.0 and under variations of organic load. The highest rate of hydrogen production, of 1.1 L.d-1.L-1, was obtained with application of an organic loading rate of 35 g.L-1.d-1, in terms of total sugar content and hydraulic retention time of 3h, with a prevalence of butyric and acetic acids as final products of the fermentation process. Low C/N ratios contributed to the excessive growth of the biomass, causing a reduction of up to 35% in hydrogen production, low percentages of H2 and high concentrations of CO2in the biogas.

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