Chemical Engineering
Chemical processes are all about separation and mixing using unit operations. Chemical processes have always been a major user of computational fluid dynamics more so than ever. In this context, the oil and gas industry is the largest consumer of CFD services. Novel reactor technologies, advanced separation systems, innovative mixing techniques, complex internals such as baffles, static mixers, blades, impellers, sieve trays and distributors, multiphase systems (gas-solid-liquid), reaction driven flows, flow through porous media, flows with diffusion and advection, complex non-Newtonian flows, fluidization bubble dynamics are some of the processes where Paanduv is an excellent choice.
Keywords: Reactor technologies, Separation systems, Oil and gas, Newtonian and non-Newtonian flows, Compressible and incompressible flows, Bio-chemical reaction.
Wastewater treatment
As per the regulations, industries can not discard the effluent water directly to the water sources. Preliminary water treatment has to be attempted for the effluent to meet the standard to be discarded in water bodies. On a large scale, chlorination is one process that is used for decades and has not found an economical replacement yet.
In the secondary treatment process, organic and inorganic impurities are dealt with. Chlorine consumption, bacterial disinfection, and ammonia removal result in the formation of disinfection by-products and sequential reactions. The occurrence of multiple reactions of different kinetics adds complexity to the system along with multiphase flows and multiphase reactions.
We are efficient in modeling primary, secondary, and tertiary treatment of water using CFD.
Fluidized Bed
Fluidization is a key mechanism in any oil and gas industry as it offers lower pressure drop, superior heat, and mass transfer. This is the regime where a solid behaves like a fluid in a specific size range. Analyses of hydrodynamic behavior in a fluidized bed reactor are crucial to deducing the performance of the reactor and the efficiency of the process. Simulations can also reveal the real-time complexity occurrence in high operating conditions.
Continuous Stirred Tank Reactor (CSTR)
Continuous stirred tank reactors are used widely for large and small-scale operations. For processes where a uniform composition is required at all times, CSTRs are used. Modeling CSTR poses an enormous simulation complexity in form of dynamic meshing due to the rotating impeller. Paanduv’s expertise in dynamic meshing can address such systems. Design and parameter optimization is performed to optimize the mixing and reduction of dead zones in the reactor. These processes can be valid for Newtonian as well as for non-Newtonian flows.
Battery Thermal Management
Electric vehicles are gaining enormous attention due to zero emissions. But the non-uniformity in temperature across battery cells and exothermic reactions leads to the rise in temperature and therefore comprised the performance and lifetime of the battery pack. This can also pose threat to safety due to thermal runaway reactions. Like humans, the battery works well and longer when operated at room temperature.
We have modeled an air-cooled battery pack system of 59 cells. Physics including conjugate heat transfer, compressible flows, pressure velocity coupling, and turbulent flows is well captured. We are capable of handling more complicated cooling mechanisms such as cold plate, liquid-cooled, phase change material cooling thermal management systems. Design and parameter optimization for the optimized arrangement of cells, size, and inlet temperature are analyzed in detail.
Gas and Solid Separator (Cyclone separator)
We have performed a simulation to eliminate dust from the air. This case is the simplified version of the separation of impurities or particulate matter from flue gas (mixture of gases) or air. Cyclone separators are used for decades that use centrifugal force for the separation of two phases (solid and liquid or gas). The tangential velocity with density difference in the two phases increases the difference in relative settling velocities.
This analogy can be implemented to solve the problem of solid slurry catalysts from liquid products.
Diffusion of Gas from Liquid to Gas-phase in a Microfluidic Channel
Oxygen transport in biological culture has been essential to many microfluidic applications, including cell-based assays, bioreactors and tissue engineering.
We have modeled the sole contribution of diffusion in flow of oxygen from liquid phase to gas phase phase. Solubility of oxygen is taken into consideration to deduce the concentration of oxygen through advection and diffusion.
Boiling and Condensation
Separation processes, boilers, thermal power plants use boiling process for large scale operations. Distillation is a process where boiling is used to efficiently separate the two constituents based on their relative volatility. In thermal power plants, boiling is used to generate steam which is used to generate electricity.
We have modeled nucleate boiling of water. The hot plate in the chamber is heated and the nucleation, bubble formation, bubble rise, bubble coalescence is analysed.
Flow through a Porous media
Porous catalyst beds, membranes, and adsorbent beds are integral components that offer higher contact time between reactants. Porous media is governed by Darcy Forchheimer's law. Processes such as the flow of gases by adsorption, porous bed, and membranes are modeled.
Design of Reactor and Process Internals
Chemical industries are hugely dependent on reactor and process internals. These internal parts such as baffles, sieve trays, static mixers, nozzles, and distributors modify the flows, improve mixing patterns, minimize the dead zones, improve atomizations, reduce maldistribution, and maintain homogeneity and reduce pressure drop. Depending upon the interest of fluids and their thermophysical properties, operating conditions, and velocities the flow regime, and bubble dynamics change. CFD is an appropriate tool to find solutions to these problems.
We have solutions to design internals and optimize the parameters for process equipment internals.
Fuel Cell
Fuel cells enable the direct conversion of chemical energy into electrical energy. The reactants are constantly reacting to produce electricity and water as the by-product. Thermal and water management in these systems poses challenges to the smooth operations of fuel cells. Minimizing the pressure drop in the bipolar plate channels is yet another area of research that seems to be never-ending. The polarization curve considering all the important aspects in fuel cells to optimize the current density is also widely explored. These problems are addressed by computational fluid dynamics (CFD) and we are working to capture all the physics involved in these cutting-edge research areas. Multiphase flows and reactions, electrochemical reactions, flow through porous media, conjugate heat transfer, and pressure velocity coupling have to be coupled to obtain the complete solution for the fuel cell.
Reaction-driven Flows (Water splitting)
Water splitting is a widely explored reaction for clean energy. Splitting of water is a multiphase reaction where H2O in liquid form generates H2 and O2 in gaseous form in presence of a photocatalyst and light. We have successfully validated the water-splitting reaction kinetics obtained by the solver with the analytical solution.
We have attempted reaction-driven flows with large complexities successfully.
Oil, Water, and Air Mechanical Separator
A key aspect of chemical engineering is separation. Major industrial efforts and energy in chemical industries go into separating the products from the impurities or catalysts, or other products based on density, boiling point (volatility), electrostatic charges, size exclusion, and freezing point. The driving force for such processes is sedimentation, boiling, potential difference, pressure difference, and cryogenic temperature difference.
We have modeled the separation of three phases oil-water-air (truly multiphase) from crude oil using mechanical separators. These are the preliminary separation methods that are used to separate the impurities from the crude oil to process it in the refinery.
Static Mixer
Static mixer is used as an static internal component for thorough mixing of the reactants before entering the reactor, so that a premixed feed enters the reactor and reduces the overall energy consumption. Sometimes depending upon the feed type-Newtonian, non-Newtonian fluids the static mixer is changed. It is used widely in oil and gas industry. We have modeled a standard Kenics mixer and validated with experimental results.
The performance of the Kenics mixer is numerically evaluated and validated with verified experimental literature. The pressure drop ratio (Z-factor) and coefficient of variation (CoV) features have been used to evaluate the mixing performance in Kenics static mixer.
Combustion
Combustion is a highly exothermic chemical reaction between the fuel and oxidizer. It has wide applicability in chemical processes starting from automotive, gasification, thermal power production, material synthesis, and explosion to aircraft engines. The details to be captured in these processes are fuel injection and mixing and flow velocity information, to measurements of combustion species and soot concentration. The detailed reaction and chemical kinetics are available in the literature. The CFD solvers are well suited for combustion problems.