The Experts below are selected from a list of 6108 Experts worldwide ranked by ideXlab platform
Rohit Ramachandran - One of the best experts on this subject based on the ideXlab platform.
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a dem model based study to quantitatively compare the effect of wet and Dry Binder addition in high shear wet granulation processes
Chemical Engineering Research & Design, 2019Co-Authors: Ashutosh Tamrakar, Sheng Wen Chen, Rohit RamachandranAbstract:Abstract Wet granulation is widely used in many particulate industries for its capability to improve flowability and handling of powder substances. A mathematical model using discrete element methodology (DEM) was developed to study two kinds of Binder addition approaches commonly used during wet granulation in a batch high-shear granulator: wet Binder addition (WBA) and Dry Binder addition (DBA). To define the complex interactions in the systems, a novel integrated DEM algorithm that incorporates powder wetting behavior, capillary and viscous liquid bridge formation as well as Binder dissolution was developed. DEM simulation results show a significant difference between the viscous regions in the particle bed for the two systems: the WBA approach quickly wets the majority of the particle bed with a low viscosity fluid, while in the DBA approach fewer particles with higher viscous surface liquid are generated that are responsible for a delayed but faster granule growth rate. The difference in the viscosity of the surface liquid in the two systems lead to varying strengths and numbers of the liquid bridge formed between particles as well as particle velocities. In general, the high viscous areas are dependent on the Binder and liquid dispersion which are affected by the mechanical agitation.
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model development and validation of fluid bed wet granulation with Dry Binder addition using a population balance model methodology
Processes, 2018Co-Authors: Shashank Venkat Muddu, Ashutosh Tamrakar, Preetanshu Pandey, Rohit RamachandranAbstract:An experimental study in industry was previously carried out on a batch fluid bed granulation system by varying the inlet fluidizing air temperature, Binder liquid spray atomization pressure, the Binder liquid spray rate and the disintegrant composition in the formulation. A population balance model framework integrated with heat transfer and moisture balance due to liquid addition and evaporation was developed to simulate the fluid bed granulation system. The model predictions were compared with the industry data, namely, the particle size distributions (PSDs) and geometric mean diameters (GMDs) at various time-points in the granulation process. The model also predicted the trends for Binder particle dissolution in the wetting liquid and the temperatures of the bed particles in the fluid bed granulator. Lastly, various process parameters were varied and extended beyond the region studied in the aforementioned experimental study to identify optimal regimes for granulation.
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compartment based population balance model development of a high shear wet granulation process via Dry and wet Binder addition
Chemical Engineering Research & Design, 2017Co-Authors: Anik Chaturbedi, Chandra Kanth Bandi, Dheeraj Reddy, Preetanshu Pandey, Ajit S Narang, Dilbir S Bindra, Li Tao, Junshu Zhao, Munir A Hussain, Rohit RamachandranAbstract:Population balance models (PBM) have been used traditionally to model high shear wet granulation (HSWG) with wet Binder addition where the Binder is pre-dissolved in a liquid and added to the granulator. However, wet granulation with Dry Binder addition can not accurately be modeled with the models developed for wet Binder addition since it involves the additional step of dissolution of the Dry Binder present in the granulator in the pure liquid added during liquid addition stage. In this work, a reduced order multi-compartment population balance model integrated with Binder dissolution model was developed to address the differences in average diameter of particles obtained from Dry and wet Binder addition. Experimental data were generated on a 10-L PMA granulator using wet and Dry Binder addition modes. The experimental data were used to estimate the model tuning parameters to validate the model which was further used as predictive tool. This model showed good agreement with experimental data in capturing the trends in average particle diameter for two different Binders, hydroxypropyl cellulose (HPC) and polyvinylpyrrolidone (PVP). The model was also able to accurately predict the average diameter for both the wet Binder and Dry Binder addition cases.
Ali Allahverdi - One of the best experts on this subject based on the ideXlab platform.
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high strength geopolymer Binder based on waste glass powder
Advanced Powder Technology, 2017Co-Authors: Mostafa Vafaei, Ali AllahverdiAbstract:Abstract This paper presents a study on the synthesis of geopolymers based on alkaline activation of waste-glass powder using aqueous solutions of sodium hydroxide and sodium silicate with different Na2O contents as alkali activators. Three types of calcium aluminate cements were also incorporated into the Dry Binder at levels up to 24% by weight in order to modify the chemical composition of the geopolymer source materials. The prepared mortars were tested for workability, setting time, compressive strength, free-alkali content and tendency towards efflorescence formation. FTIR and SEM analyses were also performed to characterize the morphology and structure of the produced geopolymer. The optimized geopolymer mortar exhibited a remarkable maximum compressive strength of 87 MPa. The results showed that inclusion of calcium aluminate cements in the silica-rich waste-glass powder leads to release high amounts of reactive alumina into aluminosilicate gels, improving the geopolymerization reactions and resulting in the formation of a more cross-linked network that exhibits higher compressive strength. High alumina cement Secar 71 showed the greatest effect in strength enhancement due to the higher amount of reactive alumina releasing into the reaction medium. The findings demonstrate a new potential of value-added reuse application for waste-glass powder by adding a suitable amount of materials that are rich in reactive alumina.
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efflorescence control in geopolymer Binders based on natural pozzolan
Cement & Concrete Composites, 2012Co-Authors: Ebrahim Najafi Kani, Ali Allahverdi, John L ProvisAbstract:Abstract This paper addresses methods to reduce efflorescence in a geopolymer Binder based on a pumice-type natural pozzolanic material from Taftan, Iran. Geopolymer pastes samples are analyzed for compressive strength and efflorescence formation after curing at 95% humidity for 28 days. To reduce the extent of efflorescence, Al-rich mineral admixtures such as metakaolin, ground granulated blast-furnace slag, and three types of calcium aluminate cements are incorporated into the Dry Binder at a range of concentrations. Hydrothermal curing at elevated temperatures also shows a positive effect in efflorescence reduction. Calcium aluminate cements show the greatest effect in efflorescence reduction, which is attributed to their dissolution in alkaline media releasing high amounts of alumina into the aluminosilicate geopolymer gel. These results confirm that it is possible to develop a more reliable geopolymer Binder with improved properties either by adding a suitable amount of active alumina to precursors such as natural pozzolan, or by manipulating the curing conditions to enhance alumina release from less-reactive precursor phases.
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effects of blast furnace slag on natural pozzolan based geopolymer cement
Ceramics-silikaty, 2011Co-Authors: Mahshad Yazdanipour, Ebrahim Najafi Kani, Ali AllahverdiAbstract:A number of geopolymer cement mixes were designed and produced by alkali-activation of a pumice-type natural pozzolan. Effects of blast-furnace slag on basic engineering properties of the mixes were studied. Different engineering properties of the mixes such as setting times and 28-day compressive strength were studied at different amounts of blast-furnace slag, sodium oxide content, and water-to-cement ratio. The mix comprising of 5 wt.% blast-furnace slag and 8 wt.% Na2O with a water-to-Dry Binder ratio of 0.30 exhibits the highest 28-day compressive strength, i.e. 36 MPa. Mixes containing 5 wt.% of ground granulated blast furnace slag showed the least efflorescence or best soundness. Laboratory techniques of X-ray diffractometry (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were utilized for characterizing a number of mixes and studying their molecular and micro-structure. Investigations done by scanning electron microscopy confirm that smaller blast-furnace slag particles react totally while the larger ones react partially with alkaline activators and contribute to the formation of a composite microstructure.
Anik Chaturbedi - One of the best experts on this subject based on the ideXlab platform.
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compartment based population balance model development of a high shear wet granulation process via Dry and wet Binder addition
Chemical Engineering Research & Design, 2017Co-Authors: Anik Chaturbedi, Chandra Kanth Bandi, Dheeraj Reddy, Preetanshu Pandey, Ajit S Narang, Dilbir S Bindra, Li Tao, Junshu Zhao, Munir A Hussain, Rohit RamachandranAbstract:Population balance models (PBM) have been used traditionally to model high shear wet granulation (HSWG) with wet Binder addition where the Binder is pre-dissolved in a liquid and added to the granulator. However, wet granulation with Dry Binder addition can not accurately be modeled with the models developed for wet Binder addition since it involves the additional step of dissolution of the Dry Binder present in the granulator in the pure liquid added during liquid addition stage. In this work, a reduced order multi-compartment population balance model integrated with Binder dissolution model was developed to address the differences in average diameter of particles obtained from Dry and wet Binder addition. Experimental data were generated on a 10-L PMA granulator using wet and Dry Binder addition modes. The experimental data were used to estimate the model tuning parameters to validate the model which was further used as predictive tool. This model showed good agreement with experimental data in capturing the trends in average particle diameter for two different Binders, hydroxypropyl cellulose (HPC) and polyvinylpyrrolidone (PVP). The model was also able to accurately predict the average diameter for both the wet Binder and Dry Binder addition cases.
Ashutosh Tamrakar - One of the best experts on this subject based on the ideXlab platform.
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a dem model based study to quantitatively compare the effect of wet and Dry Binder addition in high shear wet granulation processes
Chemical Engineering Research & Design, 2019Co-Authors: Ashutosh Tamrakar, Sheng Wen Chen, Rohit RamachandranAbstract:Abstract Wet granulation is widely used in many particulate industries for its capability to improve flowability and handling of powder substances. A mathematical model using discrete element methodology (DEM) was developed to study two kinds of Binder addition approaches commonly used during wet granulation in a batch high-shear granulator: wet Binder addition (WBA) and Dry Binder addition (DBA). To define the complex interactions in the systems, a novel integrated DEM algorithm that incorporates powder wetting behavior, capillary and viscous liquid bridge formation as well as Binder dissolution was developed. DEM simulation results show a significant difference between the viscous regions in the particle bed for the two systems: the WBA approach quickly wets the majority of the particle bed with a low viscosity fluid, while in the DBA approach fewer particles with higher viscous surface liquid are generated that are responsible for a delayed but faster granule growth rate. The difference in the viscosity of the surface liquid in the two systems lead to varying strengths and numbers of the liquid bridge formed between particles as well as particle velocities. In general, the high viscous areas are dependent on the Binder and liquid dispersion which are affected by the mechanical agitation.
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model development and validation of fluid bed wet granulation with Dry Binder addition using a population balance model methodology
Processes, 2018Co-Authors: Shashank Venkat Muddu, Ashutosh Tamrakar, Preetanshu Pandey, Rohit RamachandranAbstract:An experimental study in industry was previously carried out on a batch fluid bed granulation system by varying the inlet fluidizing air temperature, Binder liquid spray atomization pressure, the Binder liquid spray rate and the disintegrant composition in the formulation. A population balance model framework integrated with heat transfer and moisture balance due to liquid addition and evaporation was developed to simulate the fluid bed granulation system. The model predictions were compared with the industry data, namely, the particle size distributions (PSDs) and geometric mean diameters (GMDs) at various time-points in the granulation process. The model also predicted the trends for Binder particle dissolution in the wetting liquid and the temperatures of the bed particles in the fluid bed granulator. Lastly, various process parameters were varied and extended beyond the region studied in the aforementioned experimental study to identify optimal regimes for granulation.
John L Provis - One of the best experts on this subject based on the ideXlab platform.
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efflorescence control in geopolymer Binders based on natural pozzolan
Cement & Concrete Composites, 2012Co-Authors: Ebrahim Najafi Kani, Ali Allahverdi, John L ProvisAbstract:Abstract This paper addresses methods to reduce efflorescence in a geopolymer Binder based on a pumice-type natural pozzolanic material from Taftan, Iran. Geopolymer pastes samples are analyzed for compressive strength and efflorescence formation after curing at 95% humidity for 28 days. To reduce the extent of efflorescence, Al-rich mineral admixtures such as metakaolin, ground granulated blast-furnace slag, and three types of calcium aluminate cements are incorporated into the Dry Binder at a range of concentrations. Hydrothermal curing at elevated temperatures also shows a positive effect in efflorescence reduction. Calcium aluminate cements show the greatest effect in efflorescence reduction, which is attributed to their dissolution in alkaline media releasing high amounts of alumina into the aluminosilicate geopolymer gel. These results confirm that it is possible to develop a more reliable geopolymer Binder with improved properties either by adding a suitable amount of active alumina to precursors such as natural pozzolan, or by manipulating the curing conditions to enhance alumina release from less-reactive precursor phases.
