CFD modelling and simulation of drill cuttings transport efficiency in annular bends: Effect of particle sphericity

Accurate prediction of the flow behaviour of drill cuttings carried by a non-Newtonian fluid in an annular geometry is important for the successful and efficient design, operation, and optimisation of drilling operations. Although it is widely recognised that practical drilling operations hardly involve perfectly spherical cuttings, the relative ease in mathematical description coupled with speedy computation are the main reasons for the prevalence of this simplifying assumption. The possibilities offered by the modification of the interphase exchange coefficient of the Syamlal-O'Brien model as well as its scarce implementation in literature have motivated the authors to delve into this area of research as far as the transport phenomena of non-spherical drill cuttings is concerned. Another aspect of this work was influenced by the need to understand the flow dynamics around bends (horizontal to inclined and inclined to vertical sections) during deviated drilling operations using two high viscosity muds (0.5% CMC and 0.5% CMC + 4% Bentonite mud). The Eulerian-Eulerian model was adopted for this study while considering particle sphericities of 0.5, 0.75 and 1 and diameters of 0.002 m, 0.003 m, 0.004 m, 0.005 m and 0.008 m respectively. It was discovered that particle deposition intensifies at the inclined-to-vertical bend compared to other locations in the flow domain. We also observe increased dispersion effects and transport velocities of nonsphericalparticles compared to particles of a perfectly spherical geometry. Furthermore, an improvement in the rheological properties of the drilling mud shows a remarkable increase in cuttings transport efficiency especially with the smaller particles. However, increased deposition of larger particles still poses a challenge to the wellbore cleaning process despite this rheological enhancement. The proposed CFD modelling methodology is thus capable of providing critical insight into the dynamics of cuttings transport, and the resulting computationalobservations are consistent with relevant experimental investigations

Dynamic Optimisation of Fed-Batch Bioreactors for mAbs: Sensitivity Analysis of Feed Nutrient Manipulation Profiles

Successful cultivation of mammalian cells must consider careful formulation of culture media consisting of a variety of substrates and amino acids. A widely cited method for quantifying metabolic networks of mammalian cultures is dynamic flux balance modelling. Application of in-silico techniques allows researchers to circumvent time-consuming and costly in-vivo experimentation. Dynamic simulation and optimisation of reliable models allows for the visualization of opportunities to improve throughputs of target protein products, such as monoclonal antibodies (mAbs). This study presents a sensitivity analysis comparing dynamic optimisation results for industrial-scale fed-batch bioreactors, considering a variety of initial conditions. Optimized feeding trajectories are computed via Nonlinear Programming (NLP) model, employing the established IPOPT solver. Glucose, then glutamine, then asparagine, can lead to improved mAb yields and viable cell counts

Design Space Identification and Visualization for Continuous Pharmaceutical Manufacturing

Progress in continuous flow chemistry over the past two decades has facilitated significant developments in the flow synthesis of a wide variety of Active Pharmaceutical Ingredients (APIs), the foundation of Continuous Pharmaceutical Manufacturing (CPM), which has gained interest for its potential to reduce material usage, energy and costs and the ability to access novel processing windows that would be otherwise hazardous if operated via traditional batch techniques. Design space investigation of manufacturing processes is a useful task in elucidating attainable regions of process performance and product quality attributes that can allow insight into process design and optimization prior to costly experimental campaigns and pilot plant studies. This study discusses recent demonstrations from the literature on design space investigation and visualization for continuous API production and highlights attainable regions of recoveries, material efficiencies, flowsheet complexity and cost components for upstream (reaction + separation) via modeling, simulation and nonlinear optimization, providing insight into optimal CPM operation