scholarly journals Evaluation of Flocculation, Sedimentation, and Filtration for Dewatering of Scenedesmus Algae

2017 ◽  
Vol 60 (4) ◽  
pp. 1359-1367 ◽  
Author(s):  
Nicholas Rhea ◽  
John Groppo ◽  
Czarena Crofcheck
Keyword(s):  
Processing Parameters ◽  
Biofuel Production ◽  
Water Removal ◽  
Sedimentation Rates ◽  
Feed Concentration ◽  
Product Concentration ◽  
Vacuum Filtration ◽  
Cake Formation ◽  
Vacuum Belt ◽  
Solids Content

Abstract. Algae can be used as a feedstock for agricultural fertilizers, livestock and poultry feeds, anaerobic digestion, and biofuel production. For each end product, the requirements for moisture content (or solids content) vary, such that a desirable water removal strategy needs to be adaptable to varying levels of water removal. Flocculation, sedimentation, and filtration were evaluated as possible strategies for thickening and dewatering of algae. The goal of this study was to validate that algae cells treated by such means could be processed by vacuum belt filters and to determine the conditions under which the solids content could be increased to 5 to 25 wt%. The flocculation and sedimentation studies focused on conditions needed to thicken algae from a culture concentration range of 0.4 to 1 g L-1 to an end-product concentration range of 15 to 50 g L-1. Sedimentation rates of were measured with varying flocculant dosages (0 to 25 ppm) for various flocculants. The highest level of compaction was achieved with a synthetic cationic polymeric flocculant with higher molecular weight at a dosage of 15 ppm, which provided 16.3 mL of compacted solids (3.3 wt% solids). Subsequently, solids were successfully separated as a cake via gravity and vacuum filtration. The filtration studies focused on the conditions needed to filter flocculated algae slurry from a concentration range of 15 to 50 g L-1 to a product at a concentration range of 50 to 250 g L-1. Filtration rates of were measured on algae slurry treated with 10 to 15 ppm of a synthetic cationic polymeric flocculant. Processing parameters such as cake formation time, filtration rate, and mass throughput were evaluated against variables such as cake thickness, feed concentration, and processing time. Keywords: Algae, Dewatering, Filtration, Flocculation, Scenedesmus sp., Sedimentation, Thickening.

scholarly journals Estimating limits of wet pressing on paper machines

TAPPI Journal ◽  
2017 ◽  
Vol 16 (02) ◽  
pp. 81-87 ◽  
Author(s):  
J. David McDonald ◽  
Richard Kerekes
Keyword(s):  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Water Removal ◽  
Permeability Model ◽  
Paper Machines ◽  
Wet Pressing ◽  
Commercial Paper ◽  
Impulse Pressure ◽  
Solids Content ◽  
The Impact

Water removal by wet pressing on paper machines depends on many factors such as press impulse, pressure, basis weight, equilibrium moisture, rewet, furnish, and fabric properties. These factors must be considered together to estimate wet pressing limits, such as the possibility of attaining 65% solids content on commercial paper machines. We have made such estimates employing the Decreasing Permeability Model (DPM) of wet pressing. This paper describes the utility of this approach and discusses some findings, such as the large dependence of low basis weight grades on equilibrium moisture content, maximum nip pressure, and rewet. The model also estimates the impact of basis weight, web temperature, double-felting, and incoming web solids on water removed.

PROCESSING–PROPERTY RELATIONSHIPS IN WHEAT PROTEIN–UNVULCANIZED ISOPRENE RUBBER COMPOSITES

2020 ◽  
pp. 000-000
Author(s):  
Barbara L. DeButts ◽  
Justin R. Barone
Keyword(s):  
Shear Rate ◽  
Mechanical Energy ◽  
Protein Aggregates ◽  
Processing Parameters ◽  
Processing Parameter ◽  
Protein Aggregate ◽  
Protein Preparation ◽  
Tan Δ ◽  
Solids Content ◽  
Isoprene Rubber

ABSTRACT An optimized set of processing parameters was determined for trypsin hydrolyzed gliadin protein (THGd, from wheat) and unvulcanized synthetic isoprene rubber (IR) composite compounds. The compounding temperature, time, and shear dependency of the THGd:IR compounds were investigated with rheology, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Individual protein aggregates measuring ∼64 × 280 nm, with a length-to-width aspect ratio of ∼4.3, were agglomerated within the IR matrix, as measured in SEM-EDX micrographs. A higher compounding temperature (T = 150 °C) was favorable for good protein aggregate dispersion and deagglomeration, which resulted in IR reinforcement, as demonstrated by up to a 65% increase in storage modulus (G′). The tan δ was lowered by the addition of the THGd protein to IR, indicating less mechanical energy was lost as heat in the composites. As the compounding speed, that is, shear rate, was increased from 30 to 60 rpm at constant temperature (T = 150 °C), the average agglomerate size and G′ were minimally affected, but the loss tangent (tan δ) was increased, indicating an increase in IR degradation with shear rate. By drying the THGd hydrolysate at a slower rate or to a greater solids content, the composite G′ was increased and tan δ was decreased. In the slow-dried THGd hydrolysate, protein aggregates were less resistant to breakup during processing, indicating that the protein preparation was an important processing parameter.

scholarly journals Comparison of Water-Removal Efficiency of Molecular Sieves Vibrating by Rotary Shaking and Electromagnetic Stirring from Feedstock Oil for Biofuel Production

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 132
Author(s):  
Cherng-Yuan Lin ◽  
Lei Ma
Keyword(s):  
Weight Loss ◽  
Removal Efficiency ◽  
Molecular Sieves ◽  
Operating Time ◽  
Physical Structure ◽  
Biofuel Production ◽  
Electromagnetic Stirring ◽  
Water Removal ◽  
Initial Water ◽  
Rotary Shaker

Adequate water-removal techniques are requisite to remain superior biofuel quality. The effects of vibrating types and operating time on the water-removal efficiency of molecular sieves were experimentally studied. Molecular sieves of 3 Å pore size own excellent hydrophilic characteristics and hardly absorb molecules other than water. Molecular sieves of 3 Å accompanied by two different vibrating types, rotary shaking and electromagnetic stirring, were used to remove initial water from the reactant mixture of feedstock oil in order to prevent excessive growth or breeding of microorganisms in the biofuel product. The physical structure of about 66% molecular sieves was significantly damaged due to shattered collision between the magnetic bar and molecular sieves during electromagnetic stirring for 1 h. The molecular sieves vibrated by the rotary shaker appeared to have relatively higher water-removal efficiency than those by the electromagnetic stirrer and by keeping the reactant mixture motionless by 6 and 5 wt.%, respectively. The structure of the molecular sieves vibrated by an electromagnetic stirrer and thereafter being dehydrated appeared much more irregular and damaged, and the weight loss accounted for as high as 19 wt.%. In contrast, the structure of the molecular sieves vibrated by a rotary shaker almost remained original ball-shaped, and the weight loss was much less after regenerative treatment for those molecular sieves. As a consequence, the water-removal process using molecular sieves vibrated by the rotary shaker is considered a competitive method during the biofuel production reaction to achieve a superior quality of biofuels.

scholarly journals Product Concentration, Yield and Productivity in Anaerobic Digestion to Produce Short Chain Organic Acids: A Critical Analysis of Literature Data

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1538
Author(s):  
Serena Simonetti ◽  
Agus Saptoro ◽  
Claudia Fernández Martín ◽  
Davide Dionisi
Keyword(s):  
Anaerobic Digestion ◽  
Residence Time ◽  
Oxygen Demand ◽  
Short Chain ◽  
Feed Concentration ◽  
Product Concentration ◽  
Hydraulic Residence Time ◽  
Mean Values ◽  
Performance Variables ◽  
The Mean

In order to make anaerobic digestion-based processes for short chain organic acid (SCOA) production attractive, the key performance variables, i.e., concentration, yield, and productivity of the produced SCOAs need to be maximised. This study analysed recent literature, looking for the effect of process operating parameters (feed concentration, pH, temperature, and residence time) on the performance variables. Data from 551 experiments were analysed. Mean values of the SCOA concentration, yield, and productivity were 10 g l−1, 32% (chemical oxygen demand (COD) COD−1), and 1.9 g l−1 day−1, respectively. Feed concentration and residence time had the most important effect. Higher feed concentration corresponded to higher product concentration and productivity, but to lower yield. The mean feed concentration was 109 gCOD l−1 and 19 gCOD l−1 in the experiments with the highest product concentrations and in the experiments with the highest yields, respectively. Shorter residence times corresponded to higher productivity. The mean HRT (hydraulic residence time) in the experiments with the highest productivities was 2.5 days. Sequencing batch reactors gave higher values of the performance variables (mean values 29 g l−1, 41% COD COD−1, and 12 g l−1 day−1 for product concentration, yield, and productivity, respectively) than processes without phase separation.

scholarly journals Control of a Benchmark CSTR Using Feedback Linearization

2019 ◽  
Vol 2 (1) ◽  
pp. 67-75
Author(s):  
Malek Hajaya
Keyword(s):  
Feedback Linearization ◽  
Control Method ◽  
Output Regulation ◽  
Linear Control ◽  
Feed Concentration ◽  
Product Concentration ◽  
Linearization Technique ◽  
Operational Temperature ◽  
Simulation Results ◽  
Cooling Jacket

Output regulation control for a CSTR benchmark problem is considered using a feedback linearization technique, where a linear control method is applied to the system for the purpose of maximizing the yield of a desired product at a specific operational temperature. Simulation results showed that the proposed feedback linearization-based controller strategy was successful in maintaining the desired product concentration at its set points, while maintaining the cooling jacket temperate fixed at all times, and the manipulated variables were maintained within their respective operational limits. The proposed feedback linearization-based controller provided very promising results, where it guaranteed a precise operation of the reactor with good performance in terms of a stable transition with no overshoot, and exhibited robustness by rejecting the tested disturbance in the form of a sinusoidal time variation in the reactant feed concentration.

Preparation of alumina ceramics from aqueous suspensions employing the hydrolysis of aluminum nitride

2002 ◽  
Vol 17 (2) ◽  
pp. 445-450 ◽  
Author(s):  
S. Novak ◽  
T. Kosmac
Keyword(s):  
Solidification Rate ◽  
High Strength ◽  
Processing Parameters ◽  
Solidification Temperature ◽  
Transmission Electron Microscopy Analysis ◽  
Aqueous Suspensions ◽  
Transmission Electron ◽  
Electron Microscopy Analysis ◽  
Microscopy Analysis ◽  
Solids Content

This paper summarizes the effects of selected processing parameters on the behavior of aqueous alumina suspensions during hydrolysis-assisted solidification and on the properties of the green and sintered parts prepared by this technique. Measurements of the changes in viscosity, the pH, and the impedance of aqueous suspensions with time were performed to evaluate the process. Using impedance spectroscopy, the effects of the addition of AlN, the solids content in the ceramic suspension, and the effect of the solidification temperature on the progress of solidification were followed. It was demonstrated that the solidification temperature significantly affects not only the solidification rate but also the properties of the green and sintered parts. A transmission electron microscopy analysis of dry green parts revealed that the host ceramic particles are bound by a predominantly amorphous AlOOH phase, which results in a high strength for the green parts.

Characterization of ultrafiltration of undiluted and diluted stored urine

2016 ◽  
Vol 74 (9) ◽  
pp. 2105-2114 ◽  
Author(s):  
J. Ouma ◽  
S. Septien ◽  
K. Velkushanova ◽  
J. Pocock ◽  
C. Buckley
Keyword(s):  
Suspended Solids ◽  
Ionic Species ◽  
First Case ◽  
Cake Formation ◽  
Pre Treatment ◽  
Specific Cake Resistance ◽  
Solids Content ◽  
Filtration Experiment ◽  
Low Pressures

Urine ultrafiltration (UF) was studied in terms of flux, permeability, resistance and fouling. Two types of samples were used: stored urine representing the feedstock obtained from urine diversion dry toilets; and diluted stored urine representing the feedstock obtained from urinals. Three different filtration experiment sets were adopted in this study. For the first case, pressure was set in an ascending order, i.e. from 10 to 60 kPa during filtration of stored urine. For the second case, pressure was set in a descending order, i.e. from 60 to 10 kPa for the same feed stream. The third case involved filtration of diluted urine with pressure in ascending order, i.e. from 10 to 60 kPa. The results indicated that diluted urine had higher flux than undiluted urine with maximum values of 43 and 26 L·m−2·h−1 respectively. Cake formation was the dominating fouling mechanism during urine filtration with a contribution of about 90% to the total hydraulic resistance. The contribution of chemically irreversible fouling was low (−2%), unless operating from high to low pressures. Indeed, irreversible fouling appeared to be greater during the experiments starting at higher pressure. Although undiluted urine had a higher fouling potential compared to diluted urine, the specific cake resistance was higher for diluted urine, probably due to a denser cake caused by lower particle sizes in that sample. The permeate obtained after urine filtration had much lower suspended solids content compared to the feedstock, with rejections up to 99%. The concentration of the ionic species remained unchanged, and 75% of the organic compounds and dissolved solids remained in the permeate. Urine UF could then be used as pre-treatment to remove suspended solids.

TiO2 used as photocatalyst for rhodamine B degradation under solar radiation

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744095 ◽  
Author(s):  
Dessy Ariyanti ◽  
Mathilde Maillot ◽  
Wei Gao
Keyword(s):  
Wastewater Treatment ◽  
Rhodamine B ◽  
Industrial Wastewater ◽  
Advanced Oxidation Process ◽  
Processing Parameters ◽  
Degradation Pathway ◽  
Catalyst Loading ◽  
Feed Concentration ◽  
Kinetic Rate ◽  
Low Catalyst Loading

Transition metal oxide photocatalysis is a relatively new method representing advanced oxidation process to be applied in industrial wastewater treatment especially for degradation of organic pollutants. We investigate TiO2 as a photocatalyst for the photocatalytic degradation of Rhodamine B (RhB) under simulated sunlight. Various parameters and their effectiveness have been studied. The effects of processing parameters including catalyst loading and feed concentration were investigated; and the degradation pathway was proposed based on the UHPLC-MS analysis. The result showed that a higher kinetic rate can be obtained by employing low catalyst loading and feed concentration, i.e., 0.5 g/L of TiO2 loading and 5 ppm of RhB concentration, respectively. For this particular system, the optimum degradation rate ([Formula: see text]) can achieve 0.297/min. The effectiveness of solar light-TiO2 system for RhB degradation shows this method can be used for wastewater treatment.

Influence of Processing Parameters on Dehydration Effect of Positive-Pressure Horizontal Filtration

2012 ◽  
Vol 524-527 ◽  
pp. 997-1006
Author(s):  
Yan Feng Li ◽  
Wen Feng Huang ◽  
Rong Tao Zhu ◽  
Wen Da Zhao
Keyword(s):  
Filter Cake ◽  
Processing Parameters ◽  
Positive Pressure ◽  
Feed Concentration ◽  
Filtration Time ◽  
Filtration Pressure ◽  
Cake Moisture ◽  
Proportional Relationship ◽  
The Mathematical Model ◽  
Dehydration Effect

The structure of filter cake obtained by the positive horizon pressure filtration process has more advances. The paper investigated some main influencing factors about feed concentration, filtration pressure, feed grain composition on dehydration effect. And paper designs the testing program and analyses the testing results. Then paper establish the mathematical model about the filter cake moisture, filtrate concentration, the capacity of handling dry slime and the experiment influence variables. The results show that the filter mass moisture decreases as the increase of feed concentration, filtration pressure and feed size. At the same time, the filtration time, filtration pressure and feed concentration have a little influence on filtration concentration, and handling capacity of dry slime has a proportion with feed concentration and filtration pressure and has a inversely-proportional relationship with filtration time.

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