scholarly journals A Study of the Uptake of Cu²⁺ by Calcium Silicate by Batch and Continuous Reactors for Potential Commercialisation

2021 ◽  
Author(s):  
◽  
Giancarlo Barassi
Keyword(s):  
Calcium Silicate ◽  
Radial Flow ◽  
Waste Treatment ◽  
Copper Ions ◽  
Scale Up ◽  
Axial Flow ◽  
Mining Waste ◽  
Powder Xrd ◽  
Batch Processes ◽  
Rate Determining Step

<p>This study presents a significant advancement in the understanding of the uptake of Cu2+ by nanostructured calcium silicate (NCaSil) and to develop a strategy of using it in a continuous manner using packed columns. The NCaSil structure consists of micro-sized agglomeration of nanometre-sized platelets of calcium silicate. This arrangement grants the material a large surface area of 400 to 600 m2 g-1. The kinetics and thermodynamics of the adsorption of Cu2+ onto NCaSil in batch were studied at temperatures ranging from 277 to 333 K. The reaction between Cu2+ and NCaSil occurred rapidly, being endothermic and exhibiting an increase in the entropy meaning that the adsorption process became more spontaneous when the temperature was increased. Furthermore, the uptake resulted in the formation of copper sulfate hydroxide minerals in the form of Cu4(OH)6SO4·nH2O, where n is equal to 2 for wroewolfeite, 1 for posnjakite and 0 for brochantite. Using powder X-ray diffraction and scanning electron microscopy it was proven that at temperatures between 293 and 313 K wroewolfeite and posnjakite were intermediates in the formation of brochantite. Specifically at high temperatures of 333 K and Cu2+ concentrations higher than 15.7 mmol L-1 the reaction proceeded directly to the formation of the thermodynamically stable compound brochantite. A kinetic study of the crystal growth was carried out using powder-XRD which showed that the rate determining step towards the formation of brochantite is the nucleation of SO4 2-. Additionally, a value for the activation energy of 42 kJ mol-1 using powder-XRD data was obtained for the formation of the crystallographic plane 420 in the brochantite crystal. A sample of a real mining waste was collected and analysed. Based on this sample an emulated waste was generated. The NCaSil was tested for the uptake of Cu2+ ions from this emulated mining waste, showing that the use of NCaSil is feasible at pH values greater than 3. The production and use of NCaSil may be coupled to existing mining waste treatment processes in order to remove dissolved copper from solution and produce a copper rich solid as the by-product. NCaSil was packed inside a conventional axial flow column and a radial flow column, which was developed as part of this project. The former proved to be impractical due to a large pressure drop through the column, while the latter was impractical due to short operational times before breakthrough. Nonetheless, the radial flow column was operated by immersion in a tank exhibiting similar kinetics of copper ions uptake to those observed in batch processes. Therefore, the scale-up of this process was proposed including the necessary equations keeping the ratio of the tested radial flow column.</p>

scholarly journals A Study of the Uptake of Cu²⁺ by Calcium Silicate by Batch and Continuous Reactors for Potential Commercialisation

2021 ◽  
Author(s):  
◽  
Giancarlo Barassi
Keyword(s):  
Calcium Silicate ◽  
Radial Flow ◽  
Waste Treatment ◽  
Copper Ions ◽  
Scale Up ◽  
Axial Flow ◽  
Mining Waste ◽  
Powder Xrd ◽  
Batch Processes ◽  
Rate Determining Step

<p>This study presents a significant advancement in the understanding of the uptake of Cu2+ by nanostructured calcium silicate (NCaSil) and to develop a strategy of using it in a continuous manner using packed columns. The NCaSil structure consists of micro-sized agglomeration of nanometre-sized platelets of calcium silicate. This arrangement grants the material a large surface area of 400 to 600 m2 g-1. The kinetics and thermodynamics of the adsorption of Cu2+ onto NCaSil in batch were studied at temperatures ranging from 277 to 333 K. The reaction between Cu2+ and NCaSil occurred rapidly, being endothermic and exhibiting an increase in the entropy meaning that the adsorption process became more spontaneous when the temperature was increased. Furthermore, the uptake resulted in the formation of copper sulfate hydroxide minerals in the form of Cu4(OH)6SO4·nH2O, where n is equal to 2 for wroewolfeite, 1 for posnjakite and 0 for brochantite. Using powder X-ray diffraction and scanning electron microscopy it was proven that at temperatures between 293 and 313 K wroewolfeite and posnjakite were intermediates in the formation of brochantite. Specifically at high temperatures of 333 K and Cu2+ concentrations higher than 15.7 mmol L-1 the reaction proceeded directly to the formation of the thermodynamically stable compound brochantite. A kinetic study of the crystal growth was carried out using powder-XRD which showed that the rate determining step towards the formation of brochantite is the nucleation of SO4 2-. Additionally, a value for the activation energy of 42 kJ mol-1 using powder-XRD data was obtained for the formation of the crystallographic plane 420 in the brochantite crystal. A sample of a real mining waste was collected and analysed. Based on this sample an emulated waste was generated. The NCaSil was tested for the uptake of Cu2+ ions from this emulated mining waste, showing that the use of NCaSil is feasible at pH values greater than 3. The production and use of NCaSil may be coupled to existing mining waste treatment processes in order to remove dissolved copper from solution and produce a copper rich solid as the by-product. NCaSil was packed inside a conventional axial flow column and a radial flow column, which was developed as part of this project. The former proved to be impractical due to a large pressure drop through the column, while the latter was impractical due to short operational times before breakthrough. Nonetheless, the radial flow column was operated by immersion in a tank exhibiting similar kinetics of copper ions uptake to those observed in batch processes. Therefore, the scale-up of this process was proposed including the necessary equations keeping the ratio of the tested radial flow column.</p>

POWER RATE LAW BASED CHEMICAL KINETICS AND THERMODYNAMIC MODELING OF AFRICAN PEAR SEED OIL CONSECUTIVE IRREVERSIBLE BASE METHANOLYSIS FOR BIODIESEL PRODUCTION

2021 ◽  
Vol 36 (1) ◽  
pp. 53-66
Author(s):  
C. Esonye ◽  
O. D Onukwuli ◽  
S. O. Momoh
Keyword(s):  
Rate Constants ◽  
Seed Oil ◽  
Scale Up ◽  
Cetane Number ◽  
Calorific Value ◽  
Biodiesel Production ◽  
Rate Determining Step ◽  
Increase With Increase ◽  
African Pear ◽  
Kinetics And Thermodynamic

Currently the major challenge of biodiesel application as a replacement to petrodiesel is its industrial production sustainability.Consequently, the successful scale-up of laboratory results in transesterification requires so much information obtained through chemical kinetics.This paper presents the kinetics and thermodynamic study of alkali-homogeneous irreversible methanolysis of seed oil derived from African pear. The transesterification process was carried out from 0-100 minutes at temperature range of 55-65°C. The reaction mixture compositions were ascertained using gas chromatography- flame ionization detector (GC-FID) technique. Rate constants of the triglyceride (Tg), diglycerides (Dg) and monoglycerides(Mg) hydrolysis were in the range of 0.0140- 0.07810 wt%/min and increased with increase in temperature. The rate of reaction was found to increase with increase in temperature. Activation energies were found to be 6.14, 20.01 and 28.5kcal/mol at 55, 60 and 65oC respectively. Tg hydrolysis to Dg was observed asthe rate determining step while the reaction agreed with second order principles. A biodiesel yield of 93.02% was obtained with cloud point of 10°C , flash point of 125°C , pour point of 4°C , calorific value of 34.4MJ/kg, and cetane number of 54.90 which satisfy EN14214 and ASTM D 6751 standards. Results presented in this report would serve as idealized conditions for industrial scale up of biodiesel production from African pear seed oil. Keywords:Kinetics; methanolysis; rate constants; activation energy; African pear seed oil; biodiesel

Blade Loadings for Hovercraft and other Radial Flow Fans

1967 ◽  
Vol 9 (4) ◽  
pp. 265-277 ◽  
Author(s):  
A. D. S. Carter
Keyword(s):  
Radial Flow ◽  
Axial Flow ◽  
Maximum Temperature ◽  
Centrifugal Fan ◽  
Blade Loading ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Flow Compressor ◽  
High Work ◽  
Outside Diameter

The layout of a hovercraft leads naturally to the choice of a radial outward flow fan, but the aerodynamic requirements are more stringent than those normally associated with industrial fans. In this paper a blade loading criterion used extensively in axial flow compressor practice has been adapted to the more general case of radial flow fans. Using this criterion maximum fluid deflections and maximum temperature rise coefficients have been calculated. It is shown that fluid deflections in radial fans should be substantially lower than those in axial flow machines. For high work output the ratio of rotor outside diameter to rotor inside diameter should be as close to unity as is mechanically possible. Inlet guide vanes would be of no benefit to the conventional industrial type centrifugal fan, but for such applications as hovercraft inlet guide vanes could be most beneficial. The paper outlines those areas in which further research is necessary fully to confirm the approach, and hence the quantitative values, given in this paper.

scholarly journals A Radial Flow Contactor for Ambient Air CO2 Capture

2020 ◽  
Vol 10 (3) ◽  
pp. 1080 ◽  
Author(s):  
Qian Yu ◽  
Wim Brilman
Keyword(s):  
Radial Flow ◽  
Flow Reactor ◽  
Operation Mode ◽  
Scale Up ◽  
Fixed Bed ◽  
Ambient Air ◽  
Fixed Bed Reactor ◽  
Batch Mode ◽  
Radial Flow Reactor ◽  
Continuous Application

Direct air capture (DAC) of CO2 can address CO2 emissions from distributed sources and produce CO2 from air virtually anywhere that it is needed. In this paper, the performance of a new radial flow reactor (RFR) for CO2 adsorption from ambient air is reported. The reactor uses a supported amine sorbent and is operated in a batch mode of operation or semi-continuously, respectively without or with sorbent circulation. The radial flow reactor, containing 2 kg of the adsorbent, is successfully scaled up from the experimental results obtained with a fixed bed reactor using only 1 g of the adsorbent. In the batch operation mode, the sorbent in the annular space of the RFR is regenerated in situ. With sorbent circulation, the RFR is loaded and unloaded batchwise and only used as an adsorber. A sorbent batch loaded with CO2 is transported to and regenerated in an external (fluid bed) regenerator. The RFR unit is characterized by a low contacting energy (0.7–1.5 GJ/ton-CO2) and a relatively short adsorption time (24–43 min) compared to other DAC processes using the same types of sorbents. The contactor concept is ready for further scale-up and continuous application.

Scale-up of “myxalin” purification by a pseudoaffinity method using a radial flow column

1989 ◽  
Vol 28 (3-4) ◽  
pp. 157-160 ◽  
Author(s):  
A. Akoum ◽  
M. A. Vijayalakshmi ◽  
M. Sigot
Keyword(s):  
Radial Flow ◽  
Scale Up

Case Study of High Specific Speed Radial Impeller

2002 ◽  
Author(s):  
Takuji Tsugawa
Keyword(s):  
Radial Flow ◽  
Velocity Ratio ◽  
Axial Flow ◽  
Optimum Shape ◽  
Design Parameters ◽  
Shape Factors ◽  
Flow Angle ◽  
Diffusion Factor ◽  
Cavitation Performance ◽  
Specific Speed

The optimum shape of high specific speed impeller is usually axial flow impeller. The radial impeller is often used without axial flow guidevane. Usually, the radial impeller is the high pressure and low specific speed impeller. The design parameters of radial high specific speed impeller have not been obtained yet. In the previous papers, the optimum meridian shape of axial flow impeller with axial flow guidevane is obtained for various specific speed. The optimum meridian shapes calculated by diffusion factor agree with meridian shapes of conventional impellers. In this paper, the design parameters of radial high specific speed impellers without guidevane are calculated by diffusion factor. And the optimum meridian shapes of radial high specific speed impellers are proposed. In case of the radial impeller, the hub diameter is equal to the tip diameter in impeller outlet. So, in radial impellers, the outlet hub-tip ratio is 1.0. The optimum meridian shapes of radial impellers for various specific speed are also obtained in this paper. The relative efficiency and cavitation performance of impellers in various shape factors were calculated. The calculation of radial meridian shape needs four kinds of shape factors as the previous papers. The four shape factors are inlet relative flow angle β1, turning angle Δβ, axial velocity ratio (meridian velocity ratio) kc = Cm2/Cm1 and impeller diameter ratio kd = D1c/D2c inmid span streamsurface. In initial step of impeller design, the result of the efficiency and cavitation performance of impeller calculated in optimum principal design parameters is important. The principal design parameters are hub-tip ratio, inlet-outlet diameter ratio, axial velocity ratio, solidity, inlet flow angle, turning angle and blade number. The author proposed the optimum meridian profile design method by diffusion factor for various condition of design parameters. There is a good correlation between the optimum hub-tip ratio and the specific speed considering cavitation performance. The optimum solidity is obtained for the specific speed considering efficiency and cavitation performance. It was found that the optimum meridian profile of high specific speed impeller with appropriate efficiency and cavitation performance has large inclination on hub and tip stream lines. The calculated data base is four dimensional using four various shape parameter β1, Δβ, kc and kd. Using the four shape factor, the optimum meridian shape of radial flow impeller is able to be obtained. The best 1000 optimum design parameters are selected using four dimensional calculated data. The aspect of optimization is recognized with 1000 plotted data on 6 planes. The result of radial flow impeller optimization is different from that of axial flow impeller. In case of axial flow impellers, the shape factors are optimized for each specific speed. But, in radial flow impellers, if both the specific speed and the total head coefficient are given, the optimum shape factors are optimized. The calculation results between profiles and specifications were very useful for the development of new type high specific speed radial impellers.

scholarly journals Flow characteristics analysis of a two-phase suspension between rotating porous cylinders with radial and axial flows

2018 ◽  
Vol 22 (4) ◽  
pp. 1857-1864
Author(s):  
Yu-Chuan Zhu ◽  
Qing-He Xiao ◽  
Ming-Xin Gao ◽  
Qian Liu ◽  
Zhanhong Wan
Keyword(s):  
Reynolds Number ◽  
Stability Analysis ◽  
Radial Flow ◽  
Outer Cylinder ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Taylor Number ◽  
Two Phase ◽  
Characteristics Analysis ◽  
Correlation Parameters

The flow characteristics problem of the two-phase suspension in the design of filters is presented, and the hydrodynamic stability is carried out to study the flow characteristics of a two-phase suspension between a rotating porous inner cylinder and a concentric, stationary, porous outer cylinder when radial flow and axial flow are present. Linear stability analysis results in an eigenvalue problem that is solved numerically by Wan?s method. The results reveal that the critical Taylor number for the onset of instability is altered by other parameters. For given correlation parameters, increasing the axial Reynolds number increases the critical Taylor number for transition very slightly, the critical Taylor number decreases as the axial Reynolds number becomes negative.

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