Brazilian Journal of Chemical Engineering This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

Catalytic hydrogen generation from NaBH 4 /H 2 O system: effects of catalyst and promoters
Abstract A hydrogen generation system based on NaBH4 hydrolysis is affected by the nature of the catalyst and catalyst promoter. Various catalyst promoters such as Al2O3 nanoparticles, Al2O3 particles, ZrO2 sand, SiO2, MMT clay, CNT and zeolite are compared with respect to hydrogen generation (HG) and hydrogen generation rate (HGR). The highest HG and HGR are observed with alumina nanoparticles as compared to other promoters. Cobalt chloride is found to be most efficient catalyst among the other cobalt based salts (CoCl2.6H2O, CoSO4.7H2O, (CH3COO)2Co.4H2O, Co(NO3)2.H2O), cadmium based salt (CdSO4) and copper based salt (Cu...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Influence of reaction time on the structure of polyaniline synthesized on a pre-pilot scale
Abstract The aim of this work is to follow the structural variations of polyaniline (PAni) obtained by chemical oxidation on a pre-pilot scale, with different reaction times. Synthesis of PAni is well known, but when it is carried out on a pre-pilot scale, several factors can lead to structural changes and understanding these changes is important to improve controls on the synthesis process. The polymers formed were characterized by spectroscopic techniques (Raman spectroscopy, Fourier Transform Infrared - FTIR and UV-Visible). Degree of oxidation and yield were calculated for each reaction time. The analysis by FTIR, the ...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Leaching kinetics of ulexite ore in aqueous medium at different CO 2 partial pressures
Abstract This manuscript presents a study regarding the leaching kinetics of ulexite (Na2O.2CaO.5B2O3.16H2O) under different CO2 partial pressures in aqueous media. The effects of the reaction temperature, particle size, CO2 partial pressure, solid-liquid ratio, and agitation speed were investigated in the boron extraction from the ore. As a result of the experimental studies, it was found that the leaching rate increased with the rise in the reaction temperature and CO2 partial pressure, and decreased with the increase in the particle size and solid-liquid ratio. The reaction temperature was found to be a significant para...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Experimental study of the diffusion-controlled corrosion of copper in the bottom of a jet stirred reactor
Abstract Jet stirred tank reactors are usually preferred to mechanically stirred tank reactors in the case of high pressure stirred tank reactors in order to avoid the mechanical problems inherent with mechanically agitated reactors. Owing to the impact force exercised by the fluid jet on the tank bottom, the tank bottom is subjected to severe corrosion. The aim of the present work is to address this problem using an accelerated system which simulates natural diffusion-controlled corrosion of metals. Diffusion-controlled corrosion of a fixed copper disc, at the bottom of a cylindrical tank, under a single phase forced jet ...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Application of submerged membrane bioreactor technology for the treatment of high strength dairy wastewater
In this study, an aerobic submerged membrane bioreactor (sMBR) was used for the treatment of dairy wastewater at 15 h of hydraulic retention time (HRT) and 40 d of sludge retention time (SRT) with constant permeate flux (9.5 L.m-3.d-1(LMH)). The COD, ammonia-nitrogen (NH3-N) and orthophosphate (PO4-P) removal efficiencies were 98.2%, 95.4% and 88.9%, respectively. The results demonstrated that sMBR was a suitable and effective treatment for removal of organic matter and nutrients for treating dairy wastewater. The properties of the activated sludge, such as extracellular polymeric substances (EPS) and soluble microbial pro...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Development of eco-efficiency comparison index through eco-indicators for industrial applications
Abstract In the last decades companies aligned with the concepts and principles of sustainable development have been seeking to minimize the environmental and social impacts caused by their operations. Typically, the primary environmental concerns in the industry were related to water consumption, wastewater production, waste generation, energy consumption and mainly CO2 emission - which is one of the causes of the greenhouse effect. However, the environmental eco-efficiency is not clearly seen when the evaluations of these eco-indicators are individually used and, therefore, it becomes necessary to implement a methodology...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Electroremediation of deactivated catalysts from fluidised catalytic cracking for vanadium removal - the effect of a dual cathode chamber reactor
Abstract The aim of this study was to evaluate the quantity of vanadium removed through electrokinetic remediation applied to catalyst waste used in a fluid catalytic cracking process. In excess, vanadium affects process efficiency by reducing the catalyst ’ s activity, causing deactivation and reducing its useful life in petroleum cracking during refining. The electrochemical reactor used was composed of an extra cathode chamber coupled with an ion-selective cation exchange membrane, Nafion ®. The function of the cathode chamber was to increase the overpotential for a hydrogen reduction reaction (HRR) and the electric ...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Wastewater treatment in a pilot-scale submerged membrane bioreactor: study of hydrodynamics under constant operating pressure
Abstract A pilot-scale Submerged Membrane Bioreactor provided with PEI hollow fiber membranes was operated under constant pressure mode in order to evaluate the effects of hydrodynamic conditions on the process performance, such as air flow rate, module packing density and aeration configuration. For the three different air flow rates studied (2, 5 and 8 L/min), results showed a limit value for this parameter, in which above this value a better performance will not be obtained and can even be worse. The air flow rate of 5 L/min presented the best performance, followed by 8 and 2 L/min. The module packing density was studie...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Lead hazard evaluation for cathode ray tube monitors in Brazil
Abstract Cathode ray tube (CRT) monitors are electronic equipment mainly made of glass, polymers and metals. These devices became obsolete because of emerging technologies such as LCD, LED and plasma; thus generating a huge stockpile of e-waste worldwide. In this CRT study, a natural leaching simulation (NBR10005) was performed to determine the toxicity of this e-waste. The standard NBR 10005 procedure was performed for 7 different monitors. The results show all samples are hazardous according to local environmental law (NBR 10004) due to lead leaching. The CRT panel is lead free, while the CRT funnel and neck have about 2...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Feasibility of biohydrogen production by co-digestion of vinasse (sugarcane stillage) and molasses in an AnSBBR
Abstract This work studied the feasibility of biohydrogen production by co-digestion of vinasse/molasses in an AnSBBR operated with mechanical stirring (30 °C and 200 rpm). Hydrogen production by co-digestion of vinasse/sucrose was also studied to verify the performance of the process with a known co-substrate with easy degradation. The effects of influent composition (vinasse/sucrose and vinasse/molasses), influent concentration (3000 and 4000 mgCOD. L-1) and cycle time (3 and 4 h) on performance indicators were evaluated using stability, organic matter removal efficiency, molar hydrogen yield, productivity and biogas co...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Heterotrophic cultivation of Euglena gracilis on chemically pretreated media
Abstract In this research, the impact of chemical agents on the growth of Euglena gracilis and contaminants (S. cerevisiae and B. subtilis) in different cultivation media was studied. E. gracilis was cultivated on modified Hutner and complex medium in Erlenmeyer flasks and a stirred tank bioreactor. H2O2 and antimycin were used as suppressors of contaminant growth activities during algae cultivation. The use of antimycin as a chemical suppressor of contaminants is not recommendable because of its significant impact on the E. gracilis growth. At a H2O2 concentration of 5 mg L-1 contaminant growth activities were almost comp...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Ethanol production from Dekkera bruxellensis in synthetic media with pentose
This study aimed to evaluate the ability of a yeast strain of Dekkera bruxellensis in producing ethanol from synthetic media, containing xylose or arabinose, xylose and glucose as the sole carbon sources. The results indicated that D. bruxellensis was capable of producing ethanol from xylose and arabinose, with ethanol concentration similar for both carbon sources, 1.9 g L-1. For the fermentations performed with xylose and glucose, there was an increase in the concentration of ethanol to 5.9 g L-1, lower than the standard yeast Pichia stipitis (9.3 g L-1), but with similar maximum yield in ethanol (0.9 g g TOC-1). This pro...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Acetic acid production by the newly isolated Pseudomonas sp. CSJ-3
ABSTRACT A fermentative acetic acid producing strain, named CSJ-3, was isolated from sludge and identified as Pseudomonas sp. on the basis of 16S rRNA gene analysis. The effects of cultivation conditions on the production of acetic acid by Pseudomonas sp. CSJ-3 were investigated in batch fermentation, and the maximum yield of acetic acid reached up to 0.49 % during 30 h cultivation under the optimum growth condition, including fermentation temperature of 37.0 ºC, fermentation pH of 4.50, ethanol concentration of 8 %, carbon source (glucose) amount of 10 g/L, and rotation speed of 120 r/min. When ultraviolet (UV) irradiati...
Source: Brazilian Journal of Chemical Engineering - April 23, 2018 Category: Chemistry Source Type: research

Parametric study of sweetening process of sour gas by Molybdenum oxide nanoparticles
Abstract The purpose of this work is to study the application of nano-molybdenum oxide adsorbent in gas sweetening process. Experiments were made to evaluate the operating and geometrical parameters in the adsorption process. The process performance of H2S removal from methane gas on molybdenum oxide nanoparticles was defined as the ratio of final concentration of H2S on the initial concentration of H2S. The effects of operating conditions such as operating temperature, pressure, the size of nanoparticles, the amount of H2S concentration in feed stream, feed superficial velocity, and the bed length were studied in this pap...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research

CFD simulation of the mixing and dispersing of floating particles in a viscous system
Abstract Based on the Gidaspow model, the distributions of velocity, turbulence intensity, and solid concentration in stirred vessels equipped with a down-pumping propeller (TXL),a six flat-blade disc turbine (Rushton), or a down-pumping six 45 ° pitched-blade turbine (PBTD-6) in a viscous system were simulated. The power curve of the TXL propeller and the dimensionless solid concentrations of one sampling point in the vessel at different agitation speeds were obtained by simulation and experiment, which were in good agreement with each o ther. The results showed that: (1) both the tangential velocity and turbulence inten...
Source: Brazilian Journal of Chemical Engineering - February 15, 2018 Category: Chemistry Source Type: research