Biofiltration of volatile organic compounds – application to air treatment

2000 ◽  
Vol 41 (12) ◽  
pp. 183-190 ◽  
Author(s):  
E. M. Ramirez-Lopez ◽  
A. Montillet ◽  
J. Comiti ◽  
P. Le Cloirec
Keyword(s):  
Pressure Drop ◽  
Residence Time ◽  
Structural Parameters ◽  
Packing Material ◽  
Aerobic Biodegradation ◽  
Operational Conditions ◽  
Hydrodynamic Study ◽  
Wood Bark ◽  
Qualitative Measure ◽  
Empty Bed Residence Time

A hydrodynamic study and an ethanol biodegradation were carried out in an experimental biofilter using wood bark as packing material. The Comiti and Renaud model was used in order to determine, from pressure drop measurements, the tortuosity and the dynamic specific surface area of the packing material, and its structural parameters, considering the wall effect corrections. The pressure drop was used as a qualitative measure of the growth of native wood bark microorganisms. The aerobic biodegradation with a concentration of 1 g of ethanol m–3 was studied. An air superficial velocity of 100 m h–1, an air flow rate of 20 m3 h–1 and an empty bed residence time of 37 seconds with a true residence time of 19.5 s were the operational conditions in the biofilter. The ethanol concentration, pH, temperature and the pressure drop at different heights of the biofilter were measured. Performances of this process were presented.

Biofiltration de l'air pollué par le xylène : observations expérimentales

2002 ◽  
Vol 29 (4) ◽  
pp. 543-553 ◽  
Author(s):  
Hasnaa Jorio ◽  
Guy Viel ◽  
Michèle Heitz
Keyword(s):  
Carbon Dioxide ◽  
Pressure Drop ◽  
Key Words ◽  
Removal Efficiency ◽  
Residence Time ◽  
Elimination Capacity ◽  
Nutritive Solution ◽  
Filter Bed ◽  
Empty Bed Residence Time

A new filtering material has been tested for its biofiltration performance for the treatment of air contaminated with the three isomers of xylene. The biofilter, operated at an empty bed residence time of 68 s and for xylene concentrations up to 6.7 g·m–3, allowed a xylene load and reduction of more than 92% for concentrations up to 2 g·m–3, and more than 65% for concentrations less than 6.7 g·m–3. The maximum xylene elimination capacity is of 236 g·m–3·h–1. In general, the removal efficiency of meta-xylene is the highest whereas the removal efficiency of ortho-xylene is the lowest. At high xylene concentration, the increase of biodegradation intensity leads to the accumulation of a voluminous biofilm around the filtering particles, causing the clogging of the filter bed, the progressive retention of the nutritive solution in the superior parts of the bed, and the drying of the inferior parts of the bed. These observations have showed that a biofilter operating at high elimination capacities requires a meticulous control of the humidity of the filtering bed and a regular draining of the biomass excess. Key words: biofiltration, xylene, ortho, meta, and para isomers, carbon dioxide, biofilm, pressure drop, biomass excess.[Journal translation]

Performance and biofilm characteristics of a gas biofilter for n-hexane removal at various operational conditions

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48954-48960 ◽  
Author(s):  
Yan Cheng ◽  
Huijun He ◽  
Chunping Yang ◽  
Guangming Zeng ◽  
Zhou Yan ◽  
...  
Keyword(s):  
Residence Time ◽  
Nitrate Concentration ◽  
Inlet Concentration ◽  
Operational Parameters ◽  
Operational Conditions ◽  
Empty Bed Residence Time

The effects of operational parameters including nitrate concentration,n-hexane inlet concentration and gas empty bed residence time (EBRT) on long-term removal performance ofn-hexane were discussed.

Wood Bark as Packing Material in a Biofilter used for Air Treatment

2006 ◽  
Vol 27 (12) ◽  
pp. 1297-1301 ◽  
Author(s):  
Y. Andres ◽  
E. Dumont ◽  
P. Le Cloirec ◽  
E. Ramirez-Lopez
Keyword(s):  
Packing Material ◽  
Air Treatment ◽  
Wood Bark

Investigation on Flowfield and Fuel/Air Premixing Uniformities of Low Swirl Injector for Lean Premixed Gas Turbines

2021 ◽  
Author(s):  
Fujun Sun ◽  
Jianqin Suo ◽  
Zhenxia Liu
Keyword(s):  
Penetration Depth ◽  
Residence Time ◽  
Gas Turbines ◽  
Structural Parameters ◽  
Combustible Mixture ◽  
Operating Conditions ◽  
Flame Stability ◽  
Nox Emissions ◽  
Auto Ignition ◽  
Lean Premixed

Abstract Based on the development trend of incorporating fuel holes into swirler-vanes and the advantages of wide operating conditions as well as low NOx emissions of LSI, this paper proposes an original lean premixed LSI with a convergent outlet. The influence of key structures on flowfields and fuel/air premixing uniformities of LSI is investigated by the combination of laser diagnostic experiments and numerical simulations. The flowfields of LSI shows that the main recirculation zone is detached from the convergent outlet and its axial dimensions are smaller than that of HSI, which can decrease the residence time of high-temperature gas to reduce NOx emissions. The fuel/air premixing characteristics show that the positions and diameters of fuel holes affect fuel/air premixing by changing the penetration depth of fuel. And when the penetration depth is moderate, it can give full play to the role of swirling air in enhancing premixing of fuel and air. In addition, the increase of the length of the premixing section can improve the uniformity of fuel/ar premixing, but it can also weaken the swirl intensity and increase the residence time of the combustible mixture within the LSI, which can affect flame stability and increase the risk of auto-ignition. Therefore, the design and selection of LSI structural parameters should comprehensively consider the requirements of fuel/air mixing uniformity, flame stability and avoiding the risk of auto-ignition. The results can provide the technical basis for LSI design and application in aero-derivative and land-based gas turbine combustors.

scholarly journals ADSORPTION OF FLUORIDE FROM INDUSTRIAL WASTEWATER IN FIXED BED COLUMN USING JAVA PLUM (SYZYGIUM CUMINI)

2016 ◽  
Vol 9 (9) ◽  
pp. 320 ◽  
Author(s):  
Tej Pratap Singh ◽  
Sanjay Ghosh ◽  
Majumder Cb
Keyword(s):  
Residence Time ◽  
Industrial Wastewater ◽  
Fluoride Concentration ◽  
Fixed Bed ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Thomas Model ◽  
Fixed Bed Column ◽  
Empty Bed Residence Time

ABSTRACTObjective: The quality of drinking water is important for public safety and quality of life. Thus, providing every person on earth safe drinking waterseems to be the biggest challenge in front of mankind. For this purpose, here we have investigated the fluoride removal capacity of java plum.Methods: In this study, removal of fluoride from industrial wastewater using fixed-bed reactor adsorption techniques by java plum seed (Syzygiumcumini) was investigated. Fixed-bed column experiments were carried out for different bed depths, influent fluoride concentrations, and various flowrates. The Thomas model and bed depth service time model were applied to the experimental results. Both model predictions verify the experimentaldata for all the process parameters studied, indicating that the models were suitable for java plum (S. cumini) seeds (Biosorbent) fix-bed columndesign.Results: The empty bed residence time (EBRT) model optimizes the EBRT, and the Thomas model showed that the adsorption capacity is stronglydependent on the flow rate, initial fluoride concentration, and bed depth and is greater under conditions of a lower concentration of fluoride, lowerflow rate, and higher bed depth.Conclusion: The experimental results were encouraging and indicate that java plum (S. cumini) seed is a feasible option to use as a biosorbent toremove fluoride in a fixed bed adsorption process.Keywords: Adsorption, Column experiment, Thomas model, Empty bed residence time, Java plum.

Study on the Treatment of Nitrogen Oxides by Compound Bio-Filter

2012 ◽  
Vol 610-613 ◽  
pp. 1824-1828
Author(s):  
Zhi Fei Liu ◽  
De Hong Pang
Keyword(s):  
Removal Efficiency ◽  
Gas Flow ◽  
Load Capacity ◽  
Packing Material ◽  
Operating Conditions ◽  
Inlet Concentration ◽  
Trickling Filter ◽  
Spray Volume ◽  
Packing Layer ◽  
Empty Bed Residence Time

Activated carbon and wood chips were applied respectively as packing material of bio-trickling filter and bio-filter which composed the compound bio-filter and the effect of different operating parameters on NOx removal efficiency were studied. The results show that the best operating conditions of the compound bio-filter are: NO inlet concentration 604.5 mg/m3, spray volume 1.2 L/h, gas flow 0.6 m3/h(empty bed residence time 103.7 s).In such cases,NOx removal efficiency is over 96% and NOx removal load of the packing material is 29.66 g/(m3•h) . The remove of NOx is mainly completed by the packing layer of 0~50 cm height both in the bio-trickling filter and in the bio-filter, that is to say ,when the total packing layer height of the compound bio-filter is 100 cm, the purification effect is ideal and economical; The system can return to normal in about 7 hr when the dynamic load changes largely and suddenly, showing that it has strong anti shock load capacity.

scholarly journals Optimization of vane demister based on neural network and genetic algorithm

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983510 ◽  
Author(s):  
San He ◽  
Hang Liu ◽  
Yongli Zou ◽  
Qinqin Zhang
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Pressure Drop ◽  
Chemical Engineering ◽  
Separation Efficiency ◽  
Orthogonal Experiment ◽  
Structural Parameters ◽  
Experiment Design ◽  
Orthogonal Experiment Design ◽  
Operation Parameters

A vane demister is widely used for separating tiny droplets from gas streams in the petroleum industry, chemical engineering, and other industries. To obtain optimal structure and operation parameters, a method based on orthogonal experiment design is often adopted. However, in most cases, results from an orthogonal experiment design are suboptimal solutions when there are fewer experiments to optimize the vane demister performance. In this study, to obtain the maximum separation efficiency and minimum pressure drop, Fluent software was used to simulate the two-phase flow of gas and liquid in vane demister with different structural parameters and operation parameters, generating 473 solutions as the sample database. Based on this database, a back propagation neural network was used to establish the prediction model for the separation efficiency and pressure drop, and a genetic algorithm was used for multi-target optimization of this model. The optimization results were compared to Fluent simulation results and the orthogonal experiment design results. The results show that a genetic algorithm generates better results. The optimal separation efficiency of both methods is 100%. However, the optimal pressure drop of the genetic algorithm is 25.77% lower than that of the orthogonal experiment design.

Aerobic Biodegradation of Petroleum-Contaminated Soil: Simulations from Soil Microcosms

1996 ◽  
Vol 1546 (1) ◽  
pp. 121-130 ◽  
Author(s):  
David W. Ostendorf ◽  
Sharon C. Long ◽  
Theodore H. Schoenberg ◽  
Samuel J. Pollock
Keyword(s):  
Residence Time ◽  
Aerobic Biodegradation ◽  
Maximum Reaction Rate ◽  
Soil Microcosms ◽  
Maximum Reaction ◽  
Average Maximum ◽  
Petroleum Contaminated Soil ◽  
Spill Site ◽  
Aerobic Soil ◽  
Vapor Treatment

The capacity of natural bacteria to aerobically degrade hydrocarbon vapors was measured and modeled to assess the potential of bioventing to reduce exhaust vapor treatment requirements at a petroleum spill site. Five sets of aerobic soil microcosms from the vadose zone of a Massachusetts Highway Department contaminated right-of-way were dosed with different initial petroleum vapor standard concentrations, then monitored by gas chromatographic analysis over a 55-day period. The five sets yielded an average maximum reaction rate of 20 μg/m3 (soil gas)-sec, which compared favorably with studies of light hydrocarbon vapor degradation in sandy soils from other sites. The calibrated rate was incorporated into a steady-state bioventing model that simulated the evaporation of 34 000 L of petroleum over a 170-year natural release period and an 8-year accelerated release period for 10-day residence time. Aerobic degradation for a 10-day residence time reduced exhaust vapor concentrations by over 100 percent for natural release rates, with a 13 percent reduction under accelerated conditions.

Flow Simulations in Packed Beds by a Coupled DEM and CFD Approach

2012 ◽  
Author(s):  
Xiang Zhao ◽  
Trent Montgomery ◽  
Ping Lu ◽  
Sijun Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Structural Parameters ◽  
Packed Beds ◽  
Local Behavior ◽  
Cfd Simulations ◽  
Flow Simulations ◽  
Packing Structure ◽  
Computational Fluid Dynamics Cfd

This paper presents flow simulations in packed beds by a coupled discrete element method (DEM) and computational fluid dynamics (CFD) approach. The realistic packing structure in packed beds is generated by DEM. Then the packing structure is imported into the CFD preprocessor to generate a mesh for flow simulations in packed beds. The subsequent CFD simulations are carried out. The predicted results reveal that not only the local behavior but also macroscopic quantities like the pressure drop depend remarkably on the local packing structural parameters, which is unable to be taken into account when using correlations with averaged values.

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