Performance and composition of bacterial communiies in anaerobic fluidized bed reactors for hydrogen production: Effects of organic loading rate and alkalinity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Phenol degradation in an anaerobic fluidized bed reactor packed with low density support materials

The objective of this research was to study phenol degradation in anaerobic fluidized bed reactors (AFBR) packed with polymeric particulate supports (polystyrene - PS, polyethylene terephthalate - PET, and polyvinyl chloride - PVC). The reactors were operated with a hydraulic retention time (HRT) of 24 h. The influent phenol concentration in the AFBR varied from 100 to 400 mg L-1, resulting in phenol removal efficiencies of similar to 100%. The formation of extracellular polymeric substances yielded better results with the PVC particles; however, deformations in these particles proved detrimental to reactor operation. PS was found to be the best support for biomass attachment in an AFBR for phenol removal. The AFBR loaded with PS was operated to analyze the performance and stability for phenol removal at feed concentrations ranging from 50 to 500 mg L-1. The phenol removal efficiency ranged from 90-100%.

Effect of Substrate Concentration on Dark Fermentation Hydrogen Production Using an Anaerobic Fluidized Bed Reactor

The effect of substrate (glucose) concentration on the stability and yield of a continuous fermentative process that produces hydrogen was studied. Four anaerobic fluidized bed reactors (AFBRs) were operated with a hydraulic retention time (HRT) from 1 to 8 h and an influent glucose concentration from 2 to 25 gL(-1). The reactors were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 degrees C with an influent pH around 5.5 and an effluent pH of about 3.5. The AFBRs with a HRT of 2 h and a feed strength of 2, 4, and 10 gL(-1) showed satisfactory H-2 production performance, but the reactor fed with 25 gL(-1) of glucose did not. The highest hydrogen yield value was obtained in the reactor with a glucose concentration of 2 gL(-1) when it was operated at a HRT of 2 h. The maximum hydrogen production rate value was achieved in the reactor with a HRT of 1 h and a feed strength of 10 gL(-1). The AFBRs operated with glucose concentrations of 2 and 4 gL(-1) produced greater amounts of acetic and butyric acids, while AFBRs with higher glucose concentrations produced a greater amount of solvents.

Performance and composition of bacterial communities in anaerobic fluidized bed reactors for hydrogen production: Effects of organic loading rate and alkalinity

This study evaluated the effects of the organic loading rate (OLR) and pH buffer addition on hydrogen production in two anaerobic fluidized bed reactors (AFBRs) operated simultaneously. The AFBRs were fed with glucose, and expanded clay was used as support material. The reactors were operated at a temperature of 30 degrees C, without the addition of a buffer (AFBR1) and with the addition of a pH buffer (AFBR2, sodium bicarbonate) for OLRs ranging from 19.0 to 140.6 kg COD m(-3) d(-1) (COD: chemical oxygen demand). The maximum hydrogen yields for AFBR1 and AFBR2 were 2.45 and 1.90 mol H-2 mol(-1) glucose (OLR of 84.3 kg COD m(-3) d(-1)), respectively. The highest hydrogen production rates were 0.95 and 0.76 L h(-1) L-1 for AFBR1 and AFBR2 (OLR of 140.6 kg COD m(-3) d(-1)), respectively. The operating conditions in AFBR1 favored the presence of such bacteria as Clostridium, while the bacteria in AFBR2 included Clostridium, Enterobacter, Klebsiella, Veillonellaceae, Chryseobacterium, Sporolactobacillus, and Burkholderiaceae. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

Biomass Gasification in a Fluidized Bed Reactor: Effect of Temperature, Stoichiometric Ratio and Biomass Type

This paper investigates the gasification of two biomass types (pine wood and olive stones) in a laboratory scale bubbling fluidized bed reactor, in order to evaluate comparatively their potential in the production of syngas.

Fluidized-Bed Characteristics in the Coating of Nuclear Fuel Particles [electronic resource]

Mode of access: Internet.

The effect of porous walls on the power output of liquid fluidized bed reactors.

Mode of access: Internet.

Pressurized Fluidized-Bed Combustion Technology Exchange Workshop : June 5 & 6, 1979, Meadowlands Hilton Hotel, Secaucus, New Jersey /

"CONF-7906157."

Technical and economic review : B.F. Goodrich Henry Plant circulating fluidized bed demonstration : recommendation for funding.

Cover title.

Test and evaluation period of 120,000 pph atmospheric fluidized bed combustion boiler with 3,500 kw cogenerated electric power /

"ILENR/CD-87/02."

Evaluation of sulfate-bearing waste material from fluidized bed combustion of coals for soil stabilization /

Mode of access: Internet.

Modeling dimensional shrinkage of shaped foods in fluidized bed drying

Three particular geometrical shapes of parallelepiped, cylinder and sphere were selected from cut beans (length : diameter = 1: 1, 2:1, 3: 1), potatoes (aspect ratio = 1:1, 2:1, 3:1) and peas, respectively. The dimensional shrinkage behavior was studied in a batch fluidized bed at three drying temperatures of 30, 40 and 50C. Relative humidity of hot air was kept at 15%. Dimensional shrinkage was plotted using a nondimensional moisture ratio and the shrinkage behavior of the selected foods was modeled with simple mathematical models.

Solids mixing and segregation in a gas spout-fluid bed-effect of the distributor design

This work is concerned with the assessment of a newer version of the spout-fluid bed where the gas is supplied from a common plenum and the distributor controls the operational phenomenon. Thus the main body of the work deals with the effect of the distributor design on the mixing and segregation of solids in a spout-filled bed. The effect of distributor design in the conventional fluidised bed and of variation of the gas inlet diameter in a spouted bed were also briefly investigated for purpose of comparison. Large particles were selected for study because they are becoming increasingly important in industrial fluidised beds but have not been thoroughly investigated. The mean particle diameters of the fraction ranged from 550 to 2400 mm, and their specific gravity from 0.97 to 2.45. Only work carried out with binary systems is reported here. The effect of air velocity, particle properties, bed height, the relative amount of jetsam and flotsam and initial conditions on the steady-state concentration profiles were assessed with selected distributors. The work is divided into three sections. Sections I and II deal with the fluidised bed and spouted bed systems. Section III covers the development of the spout-filled bed and its behaviour with reference to distributor design and it is shown how benefits of both spouting and fluidising phenomena can be exploited. In the fluidisation zone, better mixing is achieved by distributors which produce a large initial bubble diameter. Some common features exist between the behaviour of unidensity jetsam-rich systems and different density flotsam-rich systems. The shape factor does not seem to have an affect as long as it is only restricted to the minor component. However, in the case of the major component, particle shape significantly affects the final results. Studies of aspect ratio showed that there is a maximum (1.5) above which slugging occurs and the effect of the distributor design is nullified. A mixing number was developed for unidensity spherical rich systems, which proved to be extremely useful in quantifying the variation in mixing and segregation with changes in distributor design.