No abstract

No abstract

in Wiley InterScience (www.interscience.wiley.com). In recent years there has been a growing interest in production on an industrial scale of particles with size in the sub-micron range (40-200 nm). This can be done by controlling particle formation in order to nucleate very small particles and by tailoring the particle surface in order to avoid particle aggregation and produce stable suspensions. In this work we focus on the role of turbulent mixing on particle formation in confined impinging jet reactors. In particular, we show how computational fluid dynamics and simple precipitation models could be used to derive scale-up criteria for the production of nanoparticles.

No abstract

No abstract

This paper is focused on the methods based on the Pressure Rise Test (PRT) used to monitor the primary drying of a lyophilisation process. Details about the model-based algorithms proposed to interpret the PRT, namely the Manometric Temperature Measurement (MTM), the Pressure Rise Analysis (PRA), and the Dynamic Parameters Estimation (DPE) are briefly summarized and various features of the models used by these algorithms, in particular the role of the vial wall and of radiation on the thermal balance of the system, are investigated. The optimal selection of the sampling frequency and of the time interval between two tests is discussed, and the influence of the duration of the test on the results is investigated by means of mathematical simulation: results obtained from the PRT can be significantly improved by optimizing the duration of the test. Moreover, the problem of misleading results obtained at the end of the primary drying is investigated, taking into account the problem of illconditioning of the algorithms. An improved version of the DPE algorithm is proposed to cope with this problem: its effectiveness is demonstrated by means of mathematical simulations and experimental runs.

Monitoring of the primary drying of a lyophilization process in vials / Barresi A. A.; Pisano R.; Fissore D.; Rasetto V.; Velardi S. A.; Vallan A.; Parvis M.; Galan M. AbstractAn innovative and modular system (LyoMonitor) for monitoring the primary drying of a lyophilization process in vials is illustrated: it integrates some commercial devices (pressure gauges, moisture sensor, mass spectrometer), an innovative balance and a Manometric Temperature Measurement system based on an improved algorithm (DPE) to estimate sublimating interface temperature and position, product temperature profile, heat and mass transfer coefficients and parameters required for control purposes and recipe optimisation. A soft-sensor using a multipoint wireless thermometer can also estimate the previous parameters in a large number of vials.The performances of the previous devices for the determination of the end of the primary drying are compared. Finally, all these sensors can be used for control purposes and for the optimisation of the process recipe; the use of DPE in a control loop will be shown as an example. Topical headingProcess systems engineering

No abstract