scholarly journals Release of arsenic during the carbonisation of CCA-treated wood on a laboratory and pilot scale

2006 ◽  
Vol 10 (3) ◽  
pp. 27-38 ◽  
Author(s):  
Janis Zandersons ◽  
Aivars Zhurinsh ◽  
Galina Dobele ◽  
Baiba Spince ◽  
Ausma Tardenaka ◽  
...  
Keyword(s):  
Heating Rate ◽  
Sulphuric Acid ◽  
Fixed Bed ◽  
Treated Wood ◽  
Pilot Scale ◽  
Ultrasound Treatment ◽  
Wood Moisture ◽  
Cu Content ◽  
Copper Arsenate ◽  
Concentration Levels

The release of arsenic during pyrolysis of CCA(chromated copper arsenate)-treated wood starts at a temperature below 327 ?C, but up to 600 ?C only 30-40% of the arsenic initially present in the wood is volatilised. The changes of heating rate, wood moisture, degree of the comminution and methods of pyrolysis (fixed bed or mechanically pushed and loosened bulk of chips) do not substantially change the situation. The release of arsenic can be eliminated or strongly reduced by use of carbonisation catalysts. The ways and means of metals regeneration or practical use of this contaminated charcoal are still to be elucidated. A substantial decrease of the As, Cr, and Cu content in charcoal from 2800-5550 ppm, 3700-14300 ppm, and 3500-8800 ppm, to 61 ppm, 1014 ppm, and 282 ppm, respectively, was achieved by carbonisation of the previously leached wood specimens. The leachability of CCA-salts from the wood treated with diluted sulphuric acid is good, and the amount of the leached-out metals exceeds 90-95%. Ultrasound treatment improves the leachability, although the effect is not high enough to achieve the full elimination of metals, especially chromium, to meet the concentration levels in charcoal set by legislation.

Parametric Study on Behavior of Stress-Laminated Southern Pine Bridge Decks

2000 ◽  
Vol 1740 (1) ◽  
pp. 85-95 ◽  
Author(s):  
Nur Yazdani ◽  
Joy O. Kadnar ◽  
James A. Kainz ◽  
Mike Ritter
Keyword(s):  
Bridge Decks ◽  
Treated Wood ◽  
The United States ◽  
Southern Pine ◽  
Short Term ◽  
Wood Moisture ◽  
Good Resource ◽  
Copper Arsenate ◽  
Oil Type

Stress-laminated timber bridge decks have gained popularity in the United States in recent years. As with all wood exposed to the environment, wood for these decks must be treated with preservatives. There has been reluctance to build chromated copper arsenate (CCA)-treated wood bridges because of concerns about dimensional stability. Because no research has been undertaken to investigate the use of CCA-treated southern pine stress-laminated bridge decks, a good resource for economical rural bridges has remained untapped. The objective of the present study was to evaluate the performance of various wood preservatives on stress-laminated southern pine bridge decks. A total of nine decks with seven different preservatives were built and exposed to the environment for more than 2 years. Force levels in prestressing rods and wood moisture contents from each deck were continuously monitored. It was found that the short-term variations in the rod stress levels are less for decks with oil-type preservatives than for decks with CCA preservatives. The long-term performances of decks with both preservative types were found to be similar. The anchorage effect on deck performance was found to be negligible.

Application of Biofilm Kinetics to Anaerobic Fixed Bed Reactors

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1319-1326 ◽  
Author(s):  
I. E. Gönenç ◽  
D. Orhon ◽  
B. Beler Baykal
Keyword(s):  
Removal Rate ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Pilot Scale ◽  
Cod Removal ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Removal Mechanism ◽  
Term Operation ◽  
Fixed Bed Reactors

Two basic phenomena, reactor hydraulics and mass transport through biofilm coupled with kinetic expressions for substrate transformations were accounted for in order to describe the soluble COD removal mechanism in anaerobic fixed bed reactors. To provide necessary verification, experimental results from the long term operation of the pilot scale anaerobic reactor treating molasses wastewater were used. Theoretical evaluations verified by these experimental studies showed that a bulk zero-order removal rate expression modified by diffusional resistance leading to bulk half-order and first-order rates together with the particular hydraulic conditions could adequately define the overall soluble COD removal mechanism in an anaerobic fixed bed reactor. The experimental results were also used to determine the kinetic constants for practical application. In view of the complexity of the phenomena involved it is found remarkable that a simple simulation model based on biofilm kinetics is a powerful tool for design and operation of anaerobic fixed bed reactors.

scholarly journals Evaluation of Fixed-Bed Cultures with Immobilized Lactococcus Lactis ssp. Lactis on Different Scales

2017 ◽  
Vol 11 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Rebecca Faschian ◽  
Ilyas Eren ◽  
Steven Minden ◽  
Ralf Pörtner
Keyword(s):  
Dilution Rate ◽  
Lactococcus Lactis ◽  
Scale Up ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Fixed Bed Reactor ◽  
Batch Mode ◽  
Promising Alternative ◽  
Fixed Beds ◽  
Pilot Scale Reactor

Fixed-bed processes, where cells are immobilized within macroporous carriers, are a promising alternative to processes with suspended cells. A scale-up concept is presented in order to evaluate the performance as part of process design of fixed-bed processes. Therefore,Lactococcus lactiscultivation in chemostat and batch mode was compared to fixed bed cultures on three different scales, the smallest being the downscaledMultifermwith 10 mL fixed bed units, the second a 100 mL fixed-bed reactor and the third a pilot scale reactor with 1 L fixed bed volume. As expected, the volume specific lactate productivity of all cultivations was dependent on dilution rate. In suspension chemostat culture a maximum of 2.3 g·L-1·h-1was reached. Due to cell retention in the fixed-beds, productivity increased up to 8.29 g·L-1·h-1at a dilution rate of D = 1.16 h-1(corresponding to 2.4·µmax) on pilot scale. For all fixed bed cultures a common spline was obtained indicating a good scale-up performance.

Utilisation of poultry industry wastes for liquid biofuel production via thermal and catalytic fast pyrolysis

2018 ◽  
Vol 37 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Ismail Cem Kantarli ◽  
Stylianos D Stefanidis ◽  
Konstantinos G Kalogiannis ◽  
Angelos A Lappas
Keyword(s):  
Lignocellulosic Biomass ◽  
Poultry Litter ◽  
Fast Pyrolysis ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Biofuel Production ◽  
Fluidised Bed ◽  
Nitrogenous Compounds ◽  
Catalytic Fast Pyrolysis ◽  
Bio Oil

The objective of this study was to examine the potential of poultry wastes to be used as feedstock in non-catalytic and catalytic fast pyrolysis processes, which is a continuation of our previous research on their conversion into biofuel via slow pyrolysis and hydrothermal conversion. Both poultry meal and poultry litter were examined, initially in a fixed bed bench-scale reactor using ZSM-5 and MgO as catalysts. Pyrolysis of poultry meal yielded high amounts of bio-oil, while pyrolysis of poultry litter yielded high amounts of solid residue owing to its high ash content. MgO was found to be more effective for the deoxygenation of bio-oil and reduction of undesirable compounds, by converting mainly the acids in the pyrolysis vapours of poultry meal into aliphatic hydrocarbons. ZSM-5 favoured the formation of both aromatic compounds and undesirable nitrogenous compounds. Overall, all bio-oil samples from the pyrolysis of poultry wastes contained relatively high amounts of nitrogen compared with bio-oils from lignocellulosic biomass, ca. 9 wt.% in the case of poultry meal and ca. 5–8 wt.% in the case of poultry litter. This was attributed to the high nitrogen content of the poultry wastes, unlike that of lignocellulosic biomass. Poultry meal yielded the highest amount of bio-oil and was selected as optimum feedstock to be scaled-up in a semi-pilot scale fluidised bed biomass pyrolysis unit with the ZSM-5 catalyst. Pyrolysis in the fluidised bed reactor was more efficient for deoxygenation of the bio-oil vapours, as evidenced from the lower oxygen content of the bio-oil.

scholarly journals High-Temperature, Dry Scrubbing of Syngas with Use of Mineral Sorbents and Ceramic Rigid Filters

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1528
Author(s):  
Mateusz Szul ◽  
Tomasz Iluk ◽  
Aleksander Sobolewski
Keyword(s):  
High Temperature ◽  
Fixed Bed ◽  
Pilot Scale ◽  
Industrial Applications ◽  
Filtration Process ◽  
Ceramic Filters ◽  
Gas Cleaning ◽  
The Stability

In this research, the idea of multicomponent, one-vessel cleaning of syngas through simultaneous dedusting and adsorption is described. Data presented were obtained with the use of a pilot-scale 60 kWth fixed-bed GazEla reactor, coupled with a dry gas cleaning unit where mineral sorbents are injected into raw syngas at 500–650 °C, before dedusting at ceramic filters. The research primarily presents results of the application of four calcined sorbents, i.e., chalk (CaO), dolomite (MgO–CaO), halloysite (AlO–MgO–FeO), and kaolinite (AlO–MgO) for high-temperature (HT) adsorption of impurities contained in syngas from gasification of biomass. An emphasis on data regarding the stability of the filtration process is provided since the addition of coating and co-filtering materials is often necessary for keeping the filtration of syngas stable, in industrial applications.

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