Qualification: 
Ph.D, M.Tech, B-Tech
u_bhaskarreddy@cb.amrita.edu

Dr. Udaya joined as a faculty at Amrita in 2011. He finished his Ph. D. from Florida USA in 2010. Prior to obtaining his doctoral degree, Dr. Udaya worked as a Research Specialist at AKZO NOBEL Coatings, Bangalore, India. He worked on projects funded by Department of Defense (DoD), Department of Energy (DoE) USA. During his doctoral studies, he also worked as a consultant for RENTECH Clean Energy Solutions, Colorado, USA for separating sub-micron catalyst particles from wax-catalyst slurry. Dr. Udaya has expertise in Reaction Engineering (Especially microreactor design and fabrication), Solid-Fluid Separations, Process Modeling, Simulation and Control. He has two Patents on Microchannel Reactors. He also Designed, Modeled and Simulated a DYNAMIC Settler for RENTECH.

AFFILIATIONS

QUALIFICATIONS

YEAR DEGREE/PROGRAM INSTITUTION
2011 Post doctoral Fellow Applied Research Laboratory, Florida Institute of Technology, USA
2010 Ph. D., Chemical Engineering Florida Institute of Technology, USA
2003 M.Tech., Chemical Engineering  Coimbatore Institute of Technology, Coimbatore
2001 B. Tech., Chemical Engineering Bharathiar University, Coimbatore

CERTIFICATES, AWARDS, HONORS, AND SOCIETIES

  • Cognizant Best Faculty Award, 2014
  • Distinguished Alumnus Award, 2013
  • TITAN’s of Innovation Award, 2013
  • Member, Indian Institute of Chemical Engineers, 2003- Present
  • Member Board of Studies, Chemical Engineering, Amrita Vishwa Vidyapeetham, Coimbatore
  • Life Member, Indian Society for Advancement of Materials and Processing (ISAMPE), 2011-Present

RESEARCH

RESEARCH THEMES

  • Distributed Fuel Production
  • Process Intensification

RESEARCH INTERESTS

Primary research focus of the group is to study the kinetics in small reactors, reactor design, process models for chemical reactors and model based control.

Catalysis and Reaction Engineering

Microchannel rectors gained importance in recent years due to high surface-to-volume ratios available for heat transfer. These reactors are of great importance when a high selectivity of products is required such as in Fischer-Tropsch synthesis. An integrated microchannel reactor has been designed and developed at Amrita Vishwa Vidyapeetham having a sensible heat transfer co-efficient of 5000 W/(m2. K), which is 50 times higher when compared to the conventional reactors. Deposition of catalysts onto microchannels is another challenge.
We are preparing catalysts such as cobalt Fischer-Tropsch catalyst, Pt-Sn catalyst for paraffin dehydrogenation, and mixed-oxide catalysts for Biomass and Coal gasification.
We are also studying the kinetics of oxide complexation in multi-phase reactors such as Cement rotary kilns using in situ radioisotope particle tracking.

Process Modeling and Simulation

A process model gives an edge over experiments in terms of cost and information availability but limited to real situations even under similar conditions. From modeling and simulation, we are able to simulate the heat and mass transfer, and reaction rates. The Process Modeling and Simulation group works on modeling and simulation of paraffin dehydrogenation, biomass gasification and pyrolysis, cement rotary kilns, and microchannel reactor stack.
We are developing General Reactor Modeling (GRM) Software to facilitate every reaction engineer to simulate different kind of reactors available in the chemical reactor supermarket.

Flow Dynamics and Control

Process control is very important for chemical engineers where the variables such as temperature, pressure and concentration are controlled using manipulated variables. We are currently working on model-based control of interacting systems for liquid level and temperature control. We are also working on interface tracking for drop-to-drop collisions using imaging techniques.

KEYWORDS

  • Microchannel reactors
  • Biomass gasification
  • Flow imaging
  • Catalysis

INVITED TALKS

  1. Mathematical Modeling of Fluidized Bed Coal-Gasifier, Fluid Dynamics and Its Applications, P.S.G.R.Krishnammal College for Women, December 23, 2014.
  2. Low-CO2 Refining Technologies, Advances in Green Technologies for Pollution Free Energy Sources, J.C.T. College of Engineering, August 24, 2014.
  3. Chemical Reactor Modeling, Faculty Development Workshop on Computer Aided Simulation, M.S. Ramaiah Institute of Technology, August 13, 2013.
  4. Comparison of Various Combined Cooling, Heating and Power (CCHP) Cycles and Working Fluids for the Minimization of Carbon dioxide (CO2) Emissions Using Aspen HYSYS, Chemical Control Strategies and the Contribution of Green Chemistry for Sustainable Environment, Kongu Engineering College, March 16, 2013
  5. Computer Applications of Chemical Engineering, Association of Chemical Engineers Student Chapter, Erode Sengunthar Engineering College, December 31, 2011

Publications

Publication Type: Conference Paper

Year of Publication Title

2019

S. A.K. and Dr. Udaya Bhaskar Reddy Ragula, “Effect of Catalyst Preparation Method on Mixed-paraffin Dehydrogenation”, in International Conference on Applied Materials for Energy and Health, Jafna, 2019.

2019

Sindhu S. and Dr. Udaya Bhaskar Reddy Ragula, “Catalytic and Non-Catalytic Pyrolysis of Nerium Oleander”, in 2nd Journal of Thermal Analysis and Calorimetry Conference, Budapest, Hungary, 2019.

2019

Dr. Udaya Bhaskar Reddy Ragula and Dr. Sriram Devanathan, “Efficiency Improvement in Solar Co generation using Micro channel Heat Exchangers”, in 2nd Journal of Thermal Analysis and Calorimetry Conference, Budapest, Hungary, 2019.

2018

Dr. Udaya Bhaskar Reddy Ragula, “Dynamic Split-Flow Separation of Micron-sized Slurry Fischer-Tropsch Catalyst”, in AIChE Annual Meeting, Pittsburgh, USA, 2018.[Abstract]


The rising demand for transportation fuels, and the depletion of fossil fuel resources has attracted the production of transportation fuels from renewable energy sources such as biomass. The biomass is first converted to syngas, which is further converted to liquid fuels via Fischer-Tropsch (FT) Synthesis. Iron and cobalt based catalysts are commonly used for Fisher-Tropsch Synthesis. Different technologies were developed for Fischer-Tropsch Synthesis, namely fixed bed, fluidized bed, and slurry reactors. Of the technologies mentioned, the slurry reactors are preferred because of high heat and mass transfer. Generally, the FT reactors are operated at a pressure > 20 bar and temperature > 220oC.
In a typical slurry FT reactor, the feed consists of 16 to 20 wt% catalyst. A fresh catalyst particle size ranges from 20 to 400 microns (James, N. et al., 2005; Sergio, M.,Harold, W., 2014; Basha, O., 2015). In a slurry FT reactor, the syngas will be bubbled through the catalyst slurry. The high rates of heat and mass transfer are due high degree of mixing. Due to high degree of mixing, the catalyst particles will undergo attrition and the exit catalyst particles size were reported in range of 5 to 120 micron depending on the operating conditions of the reactor (James, N. et al., 2005; Oluwaseyi, O., et al., 2006). The exit stream of a slurry reactor consists of liquid fuel and the catalyst. The catalyst particles need to be remove before they are charged into internal combustion engines, they create problems otherwise.

Different methodologies were proposed for the separation of FT catalyst from catalyst-wax slurry. The proposed methods include, batch settling, lamella settling, filtration (using cake filtration and filter press), magnetic field assisted settling (for iron catalyst).

The proposed work addresses a dynamic separation of catalyst particles from a slurry in a continuous split flow process, where the catalyst slurry fed is split in to upward and downward flows. The ratio of upward and downward velocity is a critical parameter. This dynamic split flow. For a proof of concept, the split flow settler is modelled using fundamental mass and momentum conservation equations considering the axial convection and dispersion under steady state conditions. The individual particle velocities were calculated using Richardson-Zaki model (Richardson, J.F., and Zaki, W.N., 1954). The solution of the modelled equations was obtained by using first order difference for the convection term and second order difference for the dispersion. The equations were coded in MATLAB®.

The developed model was validated against a static settler and compared results with the existing experimental results on particle segregation (Asif and Petersen, 1994). Different parameters for the split flow settler was studied namely, the slurry feed rate, particle size variation (5 to 93 microns) in the slurry, catalyst wt% in the slurry, average particle size in the feed, and the ratio of velocities between up and downward flow. It was found that, the ratio of velocities between upward and downward flow is an important parameter. It was found that all the most of the fines were removed from the fuel. The catalyst wt% in the upward flow can be brought down to less than 0.15%.

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2018

A. H.B., M., M., ,, A.K., S., and Dr. Udaya Bhaskar Reddy Ragula, “Fischer-Tropsch Synthesis over Alumina Supported Cobalt Catalyst in a Fixed-Bed Reactor”, in AIChE Annual Meeting, Pittsburgh, USA, 2018.[Abstract]


Approximately 30% of the energy is consumed in transportation in the form of gasoline, diesel and jet fuels. The ever-rising energy demands especially in the transportation sector and the depletion of fossil fuels has raised the interest in production of transportation fuels from renewable and potentially neutral source. Among the renewable source biomass stand first for the production of liquid fuels.The biomass is converted to liquid fuels in a two-step process. In the first step, the biomass is converted to syngas (a mixture of carbon monoxide and hydrogen) under controlled atmosphere. In the second step, the biomass derived syngas will be converted to liquid fuels via Fischer-Tropsch synthesis over a catalyst.
In this work, Fischer-Tropsch Synthesis was carried out using 12wt% cobalt catalyst supported over γ-Al2O3. The catalyst was synthesized using wetness impregnation technique using cobalt nitrate solution. After the impregnation, the catalyst was reduced using sodium borohydride (in the liquid-phase), whose addition was controlled by a timer-assisted peristaltic pump. After reduction, the catalyst is washed multiple times with ultrapure water to obtain neutral pH. The catalyst was loaded into a fixed-bed stainless steel reactor. The reactor temperature at the desired conditions was maintained by using a 3-zone tubular furnace (Carbolite make) and the reactor pressure was maintained using a backpressure regulator. All the experiments were carried out under isothermal conditions. The temperature was varied from 220-310oC, the pressure was varied from 5-20 atm, the hydrogen to carbon moxide ratio was varied from 0.75 to 3 and the gas hourly space velocity was varied from 5 – 100 1/hr. The products were characterized using Shimadzu GC-MS QP-2010 Plus employing Rt-Alumina Bond / Na2SO4 column and FID detector.

From the concentration of the compounds it was observed that the conversion of carbon monoxide increases with increase in temperature and pressure. But, the selectivity to hydrocarbons decreases with increase in temperature, increases with increase in pressure and also increase with increase in pressure and hydrogen to carbon monoxide ratio. The selectivity to hydrocarbons was calculated using chain growth probability (α) using Anderson-Sluz-Flory (ASF) distribution. The chain growth probability was found to vary from 0.48 to 0.76 depending on the reactor and flow conditions.

Topics:

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2017

D. Adapa, Aruna, C. M., and Dr. Udaya Bhaskar Reddy Ragula, “Modeling of Particle Breakage and Dispersion in a Slurry Fischer-Tropsch Reactor”, in AIChE Annual Meeting, Minneapolis, USA, 2017.[Abstract]


The Fischer – Tropsch synthesis (FTS) involves a catalytic reaction where synthesis gas (A mixture of carbon monoxide and hydrogen) is converted to liquid hydrocarbons of different molecular weights. FTS is a highly exothermic reaction. Among many other types of reactors, the slurry bed reactor is used in common. The heat of the reaction is removed using a heat transfer fluid flowing through the tube bundle within the reactor. The catalyst slurry and the syngas are fed to the reactor. During the course of the reaction in the slurry reactor, the catalyst particles in the slurry undergo several collisions with the other catalyst particles, tubes, and reactor walls. These collisions result in breakage/agglomeration of catalyst particles, which result in the change in shape and size of the particles. This phenomenon will alter the interfacial surface area of the catalyst for the reaction and thus the rate of the reaction will greatly be affected. Further, the change in the size of the particles will affect the settling behavior of the particles and their dispersion in the slurry. Because of this, the designed catalyst residence time in the slurry reactor may vary. This work addresses the change in residence time of the cobalt supported on alumina Fischer-Tropsch catalyst due to breakage/agglomeration. The particle breakage mechanism was coupled with multi-size particle dispersion model for analyzing the changes in the residence time. Weibull distribution was used for calculating the particle breakage probability and the size of the daughter particles was calculated using dynamic fragmentation model developed by Grady (1995). The individual particle velocities were calculated using Richardson-Zaki model. The coupled models of particle breakage with dispersion were coded in MATLAB. The concentration of the different sized catalyst particles as a function of bed height and its influence on the reaction residence time was analyzed.

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2016

A. M., R., S. Nithya, and Dr. Udaya Bhaskar Reddy Ragula, “Modeling of Fischer-Tropsch Synthesis in a Microchannel Reactor with Alumina Supported Cobalt Catalyst”, in AIChE Annual Meeting, San Francisco, 2016.

2016

Dr. Udaya Bhaskar Reddy Ragula, Dr. Sriram Devanathan, and Mohan, R., “Solar based lemon grass essential oil distillation for sustainability and livelihood in tribal community”, in GHTC 2016 - IEEE Global Humanitarian Technology Conference: Technology for the Benefit of Humanity, Conference Proceedings, 2016, pp. 738-744.[Abstract]


Lemon grass essential oil is used in manufacture of soaps, beauty products, and mosquito repellents. Nearly, 40% of world lemon grass oil is produced in India and Kerala state plays a major role. Valaramkunnu is a village in Wayanad district of Kerala, situated on the top of a hill with 300 inhabitants. The villagers walk for 8 km down the hill for daily wages as there is no other source of income. 25 acres of land is available, where lemongrass is grown naturally. The village had a history of extracting lemon grass oil, has two problems a) Batch operation - oil extraction is limited by equilibrium and b) Fire wood is used as energy source - this results in deforestation and therefore not a sustainable energy source. To address these challenges, a semi-continuous lab scale distillation was set up to overcome the limitation of equilibrium and was tested. The proposed system was initially tested at lab scale. A prototype lemon grass essential oil is setup in Valaramkunnu. For the prototype, a solar steam generation system is chosen. Effects of process parameters such as drying time, steam temperature, distillation time and packing density on oil yield were studied. It was found that 8 times more essential oil can be extracted, when compared to existing commercial methodologies. It is also estimated that, nearly 55 litres of oil per acre per annum may be produced in Valaramkunnu. Based on the current price of lemon grass oil, the villagers are estimated to earn INR 800,000 per annum. The report will describe the socioeconomic disadvantages faced by the study population, limitations of their attempts to address these disadvantages, and the analysis to rationalize projected benefits from the proposed technological and social interventions. © 2016 IEEE.

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2014

Dr. Udaya Bhaskar Reddy Ragula, S.R., S., and Rangarajan, M., “Modeling and Simulation of Mixed-Light Paraffin Dehydrogenation in a Multi-tubular Packed bed Reactors”, in International Conference on Recent Advances in Chemical, Environmental and Energy Engineering (RACEEE2014), Chennai, 2014.[Abstract]


Fluidized Catalytic Cracking (FCC) units convert high molecular compounds (from atmospheric distillation and vacuum distillation units) to light gases. The major compounds in the light gases are methane, ethane, propane and butane. These light gases are then converted to highly reactive propylene (raw material for polypropylene) and butylene (raw material for butadiene and polybutadiene) via dehydrogenation. Propane and butane are always available as mixture along with traces of methane and ethane. In any commercial dehydrogenation process, the propane and butane are separated first and then dehydrogenated separately. This certainly leads to high fixed and operating costs. In this study, mixed-feed dehydrogenation of propane and butane is proposed. An isothermal model for a multi-tubular fixed bed reactor using Pt-Sn/Al 2 O 3 as a catalyst for the dehydrogenation of mixed-paraffin feed is developed considering the axial and radial variation of concentration (2D model). The 2D model is solved using central difference scheme. The simulations were carried out using MATLAB and the developed model is tested for the effect of space velocity, reactor temperature, reactor pressure, and propane to butane ratio in the feed on total paraffin conversion and olefin yield.

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2014

Dr. Udaya Bhaskar Reddy Ragula, Shrinidhi, S. R., and Dr. Murali Rangarajan, “Mixed-Paraffin Dehydrogenation in Fixed-bed Reactors: Modeling and Simulation,”, in Institute of Chemical Engineers (AIChE) Annual Meeting, , Atlanta, 2014.

2014

N. Rasana, Rangarajan, M., and Dr. Udaya Bhaskar Reddy Ragula, “Design and Implementation of Model Predictive Control in a Three Tank Interacting System”, in International Conference on Recent Advances in Chemical, Environmental and Energy Engineering (RACEEE2014), S.S.N College of Engineering, Chennai, 2014.[Abstract]


An advanced control method, Model Predictive Control (MPC) has been widely used and well received in a wide variety of applications in process control. MPC utilizes an explicit process model to predict the future response of a process and solve a control problem with a finite horizon at each sampling instant. Model predictive control has proven to be a very effective controller design strategy over the last twenty years and has been widely used in process industry, such as oil refining, chemical engineering and metallurgy. A greater challenge for the controllers is to control an unstable system. In this work, a three tank interacting system has been used to implement Model Predictive Control for controlling the level of water in all the three tanks placed at the corners of an equilateral triangle with input, interaction and drain from each tank thus making the system a Multi-Input Multi-Output (MIMO). The appropriate model equations in the non-linear form have been formulated for the proposed system. The non-linear equations are linearized and a state space model was developed and implemented using MPC tool box of MATLAB. MPC simulation environment has been used to design the controller for the three tank interacting system and compared 
the results under various operating conditions including the constraints. The MPC behavior has been analyzed for set point control of the level of water in three tanks by tuning the extent of interaction between the tanks through the openings of solenoid valves connecting the tanks.</p>

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2009

Dr. Udaya Bhaskar Reddy Ragula, Dutta, S., Whitlow, J., and Elrod, H. Wright and, “Production of Liquid fuels using Microreactor technology”, in AIChE National Conference, Nasheville, Tennesse, USA., 2009.[Abstract]


tilization of a micro-channel reactor for production of liquid fuels from synthesis gas has been shown to lead to substantial improvement in liquid productivity compared to conventional technology. The exceptional heat transfer characteristics of the catalytic micro-channel reactor allows for significantly higher operating temperatures without excess formation of methane. Experimental results are presented showing the effect of H2/CO ratio, temperature, pressure, and space velocity on the conversion and selectivity to liquid fuels on a cobalt catalyst using Fischer-Tropsch Synthesis. A statistical analysis of these results is given indicating the primary and interaction effects for each of these variables. Also discussed are the catalyst deposition techniques employed and issues pertaining to the scale up of the micro-channel system. More »»

2004

Dr. Udaya Bhaskar Reddy Ragula, E., R., and S., G., “Modeling and Analysis of Reaction in Turbulent Flows”, in CRSYS-2004, IIT, Kharagpur, 2004.

Publication Type: Journal Article

Year of Publication Title

2019

S. Subramanian and Dr. Udaya Bhaskar Reddy Ragula, “Effect of particle size and heating rate on pyrolysis kinetics of Nerium oleander”, Chemical Engineering Communications, pp. 1-14, 2019.[Abstract]


AbstractNerium oleander is a lignocellulosic biomass which is not consumed by cattle due to its poisonous nature. The effect of two important parameters namely particle size and heating rate on thermal degradation profiles of leaves and stems of N. oleander under pyrolytic conditions were studied using thermogravimetric analysis (TGA). Experiments were conducted using heating rates from 5 to 20 °C min−1 in the pyrolysis temperature range of 0–1200 °C under 100 sccm nitrogen flow. Three different particle sizes 125, 500, and 1000 µ were considered for this study. Three degradation stages (each for hemicellulose, cellulose, and lignin) excluding the moisture loss were found for the chosen biomasses irrespective of particle size and heating rate. The kinetic rate parameters for hemicellulose, cellulose, and lignin were found using mass loss data obtained from TGA assuming first order kinetics using Coats–Redfern model. The assumed first order kinetics was proved correct for all the biomasses chosen based on the R2 value for the experimental data. Lower range of activation energy for hemicellulose and cellulose was observed for all particle sizes at lower heating rate when compared with lignin for both leaves and stems of N. oleander.

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2019

R. Kaashyap Balaji, Rajan, K. Prasad, and Dr. Udaya Bhaskar Reddy Ragula, “Modeling & optimization of renewable hydrogen production from biomass via anaerobic digestion & dry reformation”, International Journal of Hydrogen Energy, 2019.[Abstract]


There is a growing interest in the usage of hydrogen as an environmentally cleaner form of energy for end users. However, hydrogen does not occur naturally and needs to be produced through energy intensive processes, such as steam reformation. In order to be truly renewable, hydrogen must be produced through processes that do not lead to direct or indirect carbon dioxide emissions. Dry reformation of methane is a route that consumes carbon dioxide to produce hydrogen. This work describes the production of hydrogen from biomass via anaerobic digestion of waste biomass and dry reformation of biogas. This process consumes carbon dioxide instead of releasing it and uses only renewable feed materials for hydrogen production. An end-to-end simulation of this process is developed primarily using Aspen HYSYS® and consists of steady state models for anaerobic digestion of biomass, dry reformation of biogas in a fixed-bed catalytic reactor containing Ni–Co/Al2O3 catalyst, and a custom-model for hydrogen separation using a hollow fibre membrane separator. A mixture-process variable design is used to simultaneously optimize feed composition and process conditions for the process. It is identified that if biogas containing 52 mol% methane, 38 mol% carbon dioxide, and 10 mol% water (or steam) is used for hydrogen production by dry reformation at a temperature of 837.5 °C and a pressure of 101.3 kPa; optimal values of 89.9% methane conversion, 99.99% carbon dioxide conversion and hydrogen selectivity 1.21 can be obtained.

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2019

S. Suresh and Dr. Udaya Bhaskar Reddy Ragula, “A Regenerative Adsorption Technique for Removal of Uremic Toxins: An Alternative to Conventional Haeomodilayis”, Materials Today Proceeding (Accepted), 2019.

2018

S. Subramanian and Dr. Udaya Bhaskar Reddy Ragula, “Pyrolysis kinetics of Hibiscus rosa sinensis and Nerium oleander”, Biofuels, pp. 1-15, 2018.[Abstract]


Pyrolysis is a thermal method in which volatile matter present in a biomass will be degraded to lower molecular substances. This study aims at evaluation of kinetics of lignocellulosic biomass of leaves and stems of Hibiscus rosa sinensis and Nerium oleander under pyrolytic conditions, their proximate and ultimate analyses and their calorific values. Pyrolysis experiments were carried out using a thermogravimetric balance, which combines heat flux type differential thermal analysis (DTA) with thermogravimetric analysis (TGA) at different heating rates under a nitrogen atmosphere. The results were analyzed using weight loss vs. temperature and derivative weight vs. temperature profiles obtained from DTA and TGA curves. Three kinetic stages apart from moisture evaporation were observed based on the type of biomass. Kinetic parameters such as the pre-exponential factor and activation energy for each degradation step were calculated using first-order kinetics. The assumption of first-order kinetics was also proved from the experimental data. The results showed that Nerium oleander leaves are more suitable for fuel production through pyrolysis due to their higher percentage of volatile matter, low sulfur content, lower ash content, higher calorific value and lower activation energy required to decompose constituents of biomass, namely hemicellulose, cellulose and lignin.

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2017

M. Shobana, R. Prasad, K., Dr. Udaya Bhaskar Reddy Ragula, and Kumaresan, D., “Kinetics and characterization of transesterification of cottonseed oil to biodiesel using calcined clam shells as catalyst”, Biofuels, pp. 1-9, 2017.[Abstract]


ABSTRACTThe synthesis of biodiesel from cottonseed oil using heterogeneous calcined clam shells by transesterification was studied. The effects of the amount of catalyst and the oil-to-methanol ratio on the yield of the biodiesel produced were determined. A maximum yield of 84% biodiesel was obtained. Various characterization tests such as Fourier transform infrared spectroscopy (FT-IR), Gas Chromatography - Mass Spectrometry and Nuclear Magnetic Resonance Spectroscopy were carried out to ascertain the functional groups and compounds available in the product biodiesel obtained. The properties of the biodiesel using the calcined clamshell catalyst, such as density, viscosity, saponification value, iodine value and ester value, were estimated and compared with the American Society for Testing Materials standard values to determine the quality of the biodiesel produced. The yield of the biodiesel produced was modelled using response surface methodology, and contour regions were obtained. The surface morphology of the catalyst was studied using a scanning electron microscope. From the kinetics results obtained, the forward rate constant of the adsorption of methanol onto the catalyst surface was found to be very low (1.467 × 10−4), confirming that the kinetics of biodiesel production is limited by adsorption of methanol onto the active sites of the catalyst.

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2015

Dr. Udaya Bhaskar Reddy Ragula, Dutta, S., and Jennings, P., “Direct synthesis of hydrogen peroxide in a microchannel reactor/heat exchanger”, 2015.

2015

Dr. Udaya Bhaskar Reddy Ragula, Dutta, S., and Jennings, P., “Ignition time delay in hypergolic gel bipropellant combustion”, 2015.

2015

Dr. Udaya Bhaskar Reddy Ragula and R., K. Prasad, “Simulation and Optimization of Ethanolamine production, Manuscript under preparation”, 2015.

2015

N. Rajeev, Dr. Krishna Prasad R., and Dr. Udaya Bhaskar Reddy Ragula, “Process Simulation and Modeling of Fluidized Catalytic Cracker Performance in Crude Refinery”, Petroleum Science and Technology, vol. 33, no. 1, pp. 110–117, 2015.[Abstract]


The simulation of fluidized catalytic cracking (FCC) process was performed using Aspen HYSYS. The effect of crude flow rate on naphtha flow, coke yield, and catalyst to oil ratio in FCC were simulated. The interaction effects of riser height, inlet crude flow rate and operating temperature on naphtha mass flow, catalyst to oil ratio, and coke yield were studied by Box-Behnken design. The maximum yield of naphtha (100000 kg/h) was obtained for FCC operating temperature within 520–600°C and riser height greater than 30 m. The catalyst to oil ratio of above 12 was obtained for operating temperature beyond 590°C for the entire riser height variation of 10 to 60 m in FCC. The increase in riser height resulted in increase production of naphtha, but beyond 60 m of riser height secondary cracking occurs resulting in reduction in yield of naphtha.

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2014

A. R. Rajamani, Dr. Udaya Bhaskar Reddy Ragula, Kothurkar, N., and Rangarajan, M., “Nano- and micro-hexagons of bismuth on polycrystalline copper: Electrodeposition and heavy metal sensing”, CrystEngComm, vol. 16, pp. 2032-2038, 2014.[Abstract]


Hexagon-shaped bismuth nano- and micro-architectures have been electrodeposited onto polycrystalline copper electrodes from a nitrate bath at both constant current and constant potential conditions. Hexagonal geometries of varying sizes are obtained by tuning the deposition rate vis-à-vis that of a competing reaction, nitrate reduction. Nano-hexagons (100 nm to 1 μm) are obtained at 10 mA cm-2 when the HNO3 concentration is 0.2 M or less, and with 0.4 M HNO3, hexagons of sizes up to 20 μm are deposited. The obtained hexagons are polycrystalline. Further increase in nitric acid concentration results in fused sheet-like morphologies. Increasing bismuth concentration or reducing current density results in large crystallites. The ability of the obtained bismuth morphologies to detect ultratrace levels of lead has been studied. Only the nanohexagons and crystallites are able to detect lead at 1 ppb. The nanohexagons show good sensitivity to the detection of lead (LoD: 0.05 ppb or 0.24 nM; sensitivity:  0.75 μA ppb-1) using Square-Wave Anodic Stripping Voltammetry (SWASV), and clearly distinct peaks for Pb2+, Zn2+, and Cd2+, indicating the potential for this morphology as an electrocatalytic material. More »»

2014

Dr. Udaya Bhaskar Reddy Ragula, Rangarajan, M., and S.R, S., “MODELING AND SIMULATION OF MIXED-LIGHT PARAFFIN DEHYDROGENATION IN MULTI-TUBULAR FIXED BED REACTOR”, 2014.[Abstract]


Fluidized Catalytic Cracking (FCC) units convert high molecular compounds (from atmospheric distillation and vacuum distillation units) to light gases. The major compounds in the light gases are methane, ethane, propane and butane. These light gases are then converted to highly reactive propylene (raw material for polypropylene) and butylene (raw material for butadiene and polybutadiene) via dehydrogenation. Propane and butane are always available as mixture along with traces of methane and ethane. In any commercial dehydrogenation process, the propane and butane are separated first and then dehydrogenated separately. This certainly leads to high fixed and operating costs. In this study, mixed-feed dehydrogenation of propane and butane is proposed. An isothermal model for a multi-tubular fixed bed reactor using PtSn/Al2O3 as a catalyst for the dehydrogenation of mixed-paraffin feed is developed considering the axial and radial variation of concentration (2D model). The 2D model is solved using central difference scheme. The simulations were carried out using MATLAB and the developed model is tested for the effect of space velocity, reactor temperature, reactor pressure, and propane to butane ratio in the feed on total paraffin conversion and olefin yield.

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Publication Type: Book Chapter

Year of Publication Title

2019

Dr. Udaya Bhaskar Reddy Ragula, Devanathan, S., and Subramanian, S., “Modeling and Optimization of Product Profiles in Biomass Pyrolysis”, in Pyrolysis [Working Title], 2019.[Abstract]


Biomass feed comes in many varieties, but have common chief constituents of hemicellulose, cellulose, and lignin. As the relative proportions of these constituents may vary, customization of the pyrolysis process conditions is required to produce a desired product profile. By recognizing the sources of variation, the reactor settings may be intelligently controlled, to achieve optimal operation. These considerations include biomass classification, feed rate, moisture content, particle size, and interparticle thermal gradients (which arise during pyrolysis based on heating rate and temperature distribution). This chapter addresses the optimization of product profiles during biomass pyrolysis from a modeling perspective. Fundamental models for packed bed and fluidized bed pyrolyzers are developed, using kinetics from existing literature. The proposed optimization approach (inclusive of the kinetic and process models) can guide practical achievement of desired product profiles of the biomass pyrolysis process

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Publication Type: Conference Proceedings

Year of Publication Title

2015

C. Karthik, Rameshwar, V., Swati, A., Murali, R., and Dr. Udaya Bhaskar Reddy Ragula, “Modeling of Drying Stage in a Bubbling Fluidized Bed Coal Gasifier”, AIChE Annual Meeting. Salt Lake City, UT, 2015.[Abstract]


Coal is one of the world's main sources of power, providing a quarter of primary energy and more than 40% of electricity. Clean coal technology using gasification is a promising alternative to meet the global energy demand. In gasification, coal is converted to synthesis gas, a mixture of carbon monoxide and hydrogen, which is further converted to liquid fuels via Fischer-Tropsch synthesis. A typical Fischer-Tropsch synthesis accepts the synthesis gas at definite hydrogen to carbon monoxide ratio. Coal gasifiers consist of two stages namely, drying zone and gasification / reaction zone. Coal enters reaction zone after getting dried in the drying zone. Moisture level varies from 2-8% for medium and high-grade coals, and is the key for a) Temperature of the reaction zone b) Efficiency of the gasifier c) Hydrogen to carbon monoxide ratio of synthesis gas. Drying stage of a bubbling fluidized bed gasifier using hot air is modeled and simulated for 2 kg/hr of coal feed for various parameters including, initial moisture content, particle diameter, air superficial velocity, relative humidity and feed air temperature. The effect of above parameters on entry temperature of reaction zone and final moisture content in air are investigated.

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2014

Dr. Udaya Bhaskar Reddy Ragula, S.R., S., and Rangarajan, M., “Mixed-Light Paraffin Dehydrogenation in a Catalytic Multi-Tubular Reactor: Modeling and Simulation”, American Institute of Chemical Engineers (AIChE) Annual Meeting. 2014.[Abstract]


Petrochemicals such as polypropylene and polybutadiene are priced much higher than the petroleum refinery produts. Petroleum refinery units try to maximize their profits by bottom of the barrel upgradation using fluidized catalytic cracking (FCC), which converts the heavier hydrocarbons into lighter ones namely liquified petroleum gas (LPG), which predominantly contains propane and butane. The light gases (propane and butane) are feedstock for petrochemical production. These light gases are converted (dehydrogenated) to highly reactive propylene and butylene (the chief raw materials for the above mentioned petrochemicals). Propane and butane are always available as mixture along with trace quantities of methane and ethane. In any commercial process, the propane and butane are separated first and then dehydrogenated in separate reactors. This may probably lead to high fixed and operating costs. Current study proposes a process intensification method via mixed-feed dehydrogenation in a multi-tubular fixed bed catalytic reactor with Pt-Sn suppoted on γ-Al2O3. The dehydrogenation takes place at 500- 800°C and is highly endothermic. The fixed bed dehydrogenation reactor was modeled for the mixed feed of propane and butane. The reactor is simualted for various parameters under isothermal as well as adiabatic operating conditions, and the results between the two processes were compared.

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Publication Type: Patent

Year of Publication Title

2013

Dr. Udaya Bhaskar Reddy Ragula, “A Protable Microchannel Reactors for the Conversion of Biomass Derived Syngas to Liquid Fuels”, 2013.

2010

Dr. Udaya Bhaskar Reddy Ragula, Whitlow, J., Dutta, S., Wright, H., and Elrod, E., “CVD technique for the preparation/deposition of cobalt Fischer-Tropsch catalyst”, 2010.

2008

S. Dutta, Dr. Udaya Bhaskar Reddy Ragula, Whitlow, J., and Wright, H., “A New Microchannel Reactor design for efficient production of jet fuels”, 2008.

Publication Type: Report

Year of Publication Title

2008

P. Jennings, Dr. Udaya Bhaskar Reddy Ragula, and Dutta, S., “Selective Fischer-Tropsch Catalyst for Producing C9-C16 Hydrocarbons”, 2008.[Abstract]


A conceptual Fischer-Tropsch (FT) based process is proposed for converting synthesis gas to C9 C16 hydrocarbons suitable for Navy use as synthetic JP5 fuel. We shall develop an advanced FT catalyst selective for C5-C8 olefins that will be subsequently dimerized to C10-C16; optionally, the process will include product upgrading, e.g., partial reduction. Phase I will investigate in parallel two crucial issues: (1) Development of a suitable FT catalyst based on zeolite supported ruthenium (at Eltron), and (2) Design of a novel FT multi-channel reactor (MCR) with ultra-efficient heat removal capability for near-isothermal operation at relatively low temperature and high pressure (at Florida Institute of Technology). The developed catalyst will first be tested for its potential in the proposed performance using a packed-bed mini-reactor with highly efficient heat removal; initial MCR testing will follow. Phase II will investigate full operation of the MCR, the dimerization reaction, and product separation, recycle and upgrading; more catalyst development will include aging and regeneration studies in addition to optimization, full characterization, and scale-up. Successful Phase I and II will lead to Phase III -- building and operating a fully-integrated prototype JP5 FT mini-plant based on syngas from natural gas reforming.

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COURSES

CODE SUBJECT
CHE 211 Fluid Mechanics for Chemical Engineers
CHE 212 Chemical Engineering Thermodynamics
CHE 311 Chemical Reaction Engineering
CHE 393 Chemical Reaction Engineering Laboratory
CHE 397 Computational Methods in Chemical Engineering
CHE 461 Chemical Process Modeling and Simulation
CHE 462 Computational Methods in Fluid Dynamics
CHE 491 Computer Aided-Design of Chemical Processes
CL 601 Mathematical Methods in Chemical Engineering
CL 603 Chemical Reactor Design and Analysis
CL 717 Process Intensification

Summary

My professional interests circle around multiphase and compact integrated microchannel reactors. We are trying to address the issues with design of compact microchannel heat exchanger starting from feed mal-distribution, short-circuting, efficient gasket design, catalyst design and deposition onto microchannels and catalyst regeneration. We have designed and fabricated a microchannel reactor which has 500 times more heat transfer capability when compared to commercially available multi-phase reactors. We are in the process of addressing the mixing phenomenon in rotary kilns using radiotracer techniques. We are also designing a two-stage biomass gasifier for efficient conversion of Biomass/Plastic waste to syngas. We are also currently involved in developing General Reactor Modeling Software, which is a single step solution for all types of Chemical Reactor Simulations.