Modeling a Silicon CVD Spouted Bed Pilot Plant Reactor

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Juliana Piña ◽  
Verónica Bucalá ◽  
Noemí Susana Schbib ◽  
Paul Ege ◽  
Hugo Ignacio de Lasa
Keyword(s):  
Population Balance ◽  
Particle Growth ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Spouted Bed ◽  
Reactor Model ◽  
Plant Reactor ◽  
Short And Long Term ◽  
Pilot Scale Reactor

This study reports a comprehensive multiphase gas-solid dynamic mathematical model that successfully describes the batch growth of silicon particles in a CVD submerged spouted bed reactor. This multiphase reactor model takes into account the hydrodynamics and interphase mass exchange between the different fluidized bed regions (spout or grid zone, bubbles and emulsion phase) and uses applicable kinetic rate models to describe both heterogeneous and homogeneous reactions. The model also incorporates a population balance equation representing particle growth and agglomeration.The CVD submerged spouted bed reactor operation is simulated by means of a sequential modular procedure, which involves the solution of the reactor model and the population balance equation.It is shown that the proposed CVD multiphase reactor model successfully simulates experimental data obtained from batch operation in a pilot scale reactor at REC Silicon Inc. The modeling of experiments obtained for different operating conditions allows correlating the scavenging factor as a function of the silane concentration for short- and long-term operations.

Effect of Surface Properties on Particle Growth Kinetics for Polymer Coating in Spouted Bed

2012 ◽  
Vol 727-728 ◽  
pp. 1616-1621 ◽  
Author(s):  
Boeira Braga Matheus ◽  
Cristina dos Santos Rocha Sandra
Keyword(s):  
Surface Energy ◽  
Surface Properties ◽  
Growth Kinetics ◽  
Particle Growth ◽  
Operating Conditions ◽  
Polymeric Film ◽  
Spouted Bed ◽  
Particle Coating ◽  
Solids Concentration ◽  
Before And After

In this research, glass beads with size range between 1.68 and 2mm were coated with 5 polymeric suspensions. The suspensions formulations differ in relation to their employment and physical properties (solids concentration, surface tension and rheology), generating different characteristics of wettability and adhesion with the nucleus. The aim of this study was to evaluate particle coating in a spouted bed through analysis of particle growth in terms of solid surface energy, wettability, and adhesion before and after the formation of the first layer of polymeric film on the particle. The solid-suspension and film-suspension systems were characterized by contact angle and surface energy. The operating conditions were fixed for all suspensions: 1.5 kg of beads, air velocity of 0.369 m/s, air temperature of 60 °C, suspension flow rate of 4 ml and atomizing pressure of 10 psig. Analyzing particle growth kinetics, different behaviors were observed and related not only to glass-suspension wettability, but also to polymeric film-suspension surface properties.

Long-term operation of a pilot-scale reactor for phosphorus recovery as struvite from source-separated urine

2016 ◽  
Vol 92 (5) ◽  
pp. 1035-1045 ◽  
Author(s):  
Patricia Zamora ◽  
Tanya Georgieva ◽  
Inmaculada Salcedo ◽  
Nico Elzinga ◽  
Philipp Kuntke ◽  
...  
Keyword(s):  
Pilot Scale ◽  
Phosphorus Recovery ◽  
Term Operation ◽  
Pilot Scale Reactor ◽  
Scale Reactor

Investigation of Ammonia Formation During Gasification in an Air Blown Spouted Bed

2002 ◽  
Author(s):  
N. Paterson ◽  
Y. Zhuo ◽  
D. R. Dugwell ◽  
R. Kandiyoti
Keyword(s):  
Temperature Control ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Spouted Bed ◽  
Fuel Gas ◽  
Bed Temperature ◽  
Control Options ◽  
High Concentrations ◽  
Ammonia Formation

High NH3 concentrations were measured in the fuel gas produced by a pilot scale, air blown gasifier that was operated by British Coal. A laboratory scale gasifier has subsequently been developed to investigate the reactions that produce these potentially high concentrations. It has been found that in addition to the NH3 formed through pyrolytic processes, the introduction of steam (or H2 produced by its decomposition) increases the amount formed. The latter reaction produced the higher proportion of the total NH3. The effect of the gasifier operating conditions on the amount of NH3 formed has been studied. The main control options to minimise the NH3 formed are using an alternative method of bed temperature control (i.e. avoid the use of steam), operating with higher bed temperatures and operation at lower pressures.

A pilot-scale photocatalyst-membrane hybrid reactor: performance and characterization

2005 ◽  
Vol 51 (6-7) ◽  
pp. 491-497 ◽  
Author(s):  
J. Ryu ◽  
W. Choi ◽  
K.-H. Choo
Keyword(s):  
Humic Acids ◽  
Membrane Surface ◽  
Initial Period ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Hybrid Reactor ◽  
Suction Pressure ◽  
Reactor Performance ◽  
Uv Illumination ◽  
Pilot Scale Reactor

We developed and tested a pilot-scale photocatalyst-membrane hybrid reactor for water treatment. The performance of the pilot-scale reactor was evaluated by monitoring the degradation efficiency of several organic pollutants and the membrane suction pressure at different operating conditions. The concentration of humic acids rather increased in the initial period of UV illumination and then decreased gradually, which could be ascribed to the photoinduced desorption of humic acids from the TiO2 surface. The decoloring rate of methylene blue was faster than that of rhodamine B, whereas the order of mineralization rates of the dyes was reversed. 4-chlorophenol of 100 ppb was fully degraded under UV irradiation in 2 hours, which suggests that this hybrid reactor would be more suitable in removing micropollutants in water. The reactor was operated with either continuous or intermittent suction mode. In a continuous suction mode, the formation of TiO2 cake layers on the membrane surface occurred and caused a substantial increase in suction pressure. However, no further fouling (or suction pressure build-up) took place with an intermittent suction mode with the 9-min suction and 3-min pause period. The photocatalyst-membrane hybrid reactor system developed in this study could be an attractive option for controlling micropollutants in water.

Tertiary nitrification in aerated pilot biofilters

1994 ◽  
Vol 29 (10-11) ◽  
pp. 53-60 ◽  
Author(s):  
M. Tschui ◽  
M. Boller ◽  
W. Gujer ◽  
J. Eugster ◽  
C. Mäder ◽  
...  
Keyword(s):  
Pilot Scale ◽  
Operating Conditions ◽  
Nitrification Rate ◽  
Measured Temperature ◽  
Exponential Relationship ◽  
Effluent Quality ◽  
Different Types ◽  
Long Term Performance ◽  
Term Performance

Three different types of internally aerated pilot scale biofilters were operated as tertiary nitrification systems. Long-term performance of the three aerated biofilters was tested under various operating conditions. The maximum volumetric nitrification rates under non NH4-limiting conditions for the three aerated biofilter systems were investigated. Based on measured temperature dependencies, an exponential relationship was established enabling the prediction of the nitrification rates at desired temperatures. Based on a temperature of 10°C, the results allow a comparison between the surface and volume specific nitrification rates in the tested biofilters as a function of the NH4 effluent concentration. As shown by experiments, nitrification performance depends on water as well as air velocities in the filter. Higher velocities of both air and water increase the nitrification rate. However, they also increase the head loss and thus decrease the filter run time. Therefore, the optimal operating conditions depend also on the filter media and the required effluent quality. Compared to fully O2-limiting operating conditions, nitrification performance during a period under partially NH4-limiting conditions clearly decreased in all tested biofilters.

Electrochemical pilot scale study for reduction of 2,4-DNT

2003 ◽  
Vol 47 (9) ◽  
pp. 173-178 ◽  
Author(s):  
R. Doppalapudi ◽  
D. Palaniswamy ◽  
G. Sorial ◽  
S. Maloney
Keyword(s):  
Continuous Flow ◽  
Feed Solution ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Batch Mode ◽  
Graphite Cylinder ◽  
Batch Simulation ◽  
Pilot Scale Reactor ◽  
Flow Experiments

An electrochemical pilot scale reactor was used to treat simulated munitions wastewater containing 100 mg/L of 2,4-dinitrotoluene (DNT). Experiments were conducted by using a glassy carbon (zero porosity) coated graphite cylinder as the cathode and a platinum wire as the anode. All experiments were conducted under dissolved oxygen concentration of less than 1.5 mg/L. Initially, experiments simulating batch conditions were conducted to obtain the optimum operating conditions for the reactor. During this batch-mode study, the effects of various parameters such as applied current, electrolyte concentration, and type of electrolyte on the reduction of DNT were evaluated. Results obtained showed that the rates of reduction of DNT increased with an increase in current or concentration of electrolyte. Based on the results obtained from the batch simulation experiments, continuous flow experiments were conducted at three different currents. The ionic strength of the feed solution was maintained at 0.027 M. A current of 200 mA was found to provide a stable reduction of DNT at the 80% level for a period of 14 days after which reactor cleaning is necessary for removal of solids that were formed within the reactor. End products determined for the continuous flow experiments showed 100% molar balance conversion.

scholarly journals Process characterization and energy balance of air wood residues gasification using continuous operated pilot scale reactor

2020 ◽  
Vol 180 ◽  
pp. 02018
Author(s):  
Cora Gheorghe-Bulmau ◽  
Raluca Nicoleta Tirtea ◽  
Gabriela Ionescu ◽  
Cosmin Marculescu
Keyword(s):  
Energy Balance ◽  
Rotary Kiln ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Major Influence ◽  
Fuel Gas ◽  
Gasification Process ◽  
Process Characterization ◽  
Pilot Scale Reactor

This work aimed to study the effect of gasification process operating conditions on syngas composition and properties, and process efficiency. A rotary kiln gasifier lab-scale pilot plant with capacity ≅ 30 kg/h and a power of 30 kWe was used for gasification tests applied to cherry wood at different loads, for a temperature of about 600°C, while the air was used as gasification agent for all tests. The syngas composition was measured and analyzed. The results have shown that conversion of wood cherry through gasification lead to a lean fuel gas of 3.5 MJ/Nm3 and installation characteristics have a major influence both on process and syngas properties. This is happened because the rotary kiln gasifier allows some air infiltrations, and consequently a high N2 content in the syngas composition. The energy balance of the cherry biomass gasification processes was calculated. It was found also that gas density varies slightly from 1.26 to 1.43 kg/m3, while the specific heat of the gas varies from 1.04 to 1.34 kJ/kgK.

Short- and Long-Term Results of Total vs Subtotal Thyroid- ectomies in the Surgical Treatment of Graves' Disease

Swiss Surgery ◽  
2001 ◽  
Vol 7 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Robert ◽  
Mariéthoz ◽  
Pache ◽  
Bertin ◽  
Caulfield ◽  
...  
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Nerve Palsy ◽  
Recurrent Laryngeal Nerve Palsy ◽  
Laryngeal Nerve ◽  
Long Term Results ◽  
Graves Disease ◽  
Laryngeal Nerve Palsy ◽  
Short And Long Term

Objective: Approximately one out of five patients with Graves' disease (GD) undergoes a thyroidectomy after a mean period of 18 months of medical treatment. This retrospective and non-randomized study from a teaching hospital compares short- and long-term results of total (TT) and subtotal thyroidectomies (ST) for this disease. Methods: From 1987 to 1997, 94 patients were operated for GD. Thirty-three patients underwent a TT (mostly since 1993) and 61 a ST (keeping 4 to 8 grams of thyroid tissue - mean 6 g). All patients had received propylthiouracil and/or neo-mercazole and were in a euthyroid state at the time of surgery; they also took potassium iodide (lugol) for ten days before surgery. Results: There were no deaths. Transient hypocalcemia (< 3 months) occurred in 32 patients (15 TT and 17 ST) and persistent hypocalcemia in 8 having had TT. Two patients developed transient recurrent laryngeal nerve palsy after ST (< 3 months). After a median follow-up period of seven years (1-15) with five patients lost to follow-up, 41 patients having had a ST are in a hypothyroid state (73%), thirteen are euthyroid (23%), and two suffered recurrent hyperthyroidism, requiring completion of thyroidectomy. All 33 patients having had TT - with follow-ups averaging two years (0.5-8) - are receiving thyroxin substitution. Conclusions: There were no instances of persistent recurrent laryngeal nerve palsy in either group, but persistent hypoparathyroidism occurred more frequently after TT. Long after ST, hypothyroidism developed in nearly three of four cases, whereas euthyroidy was maintained in only one-fourth; recurrent hyperthyroidy was rare.

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