Modelling approach of a devolatilization-combustion process in a well stirred reactor

Object of this work is the definition of the optimal operative parameters of an experimental industrial burner working in flameless conditions. To reach this objective the main steps are described in the following. First, a parametrical optimization of the carbon oxy-combustion process in pressurized environment was performed. When carbon is injected in the combustor in slurry form, the particles break due to the combined effect of the shear stress induced by the injected air swirled and of the particle devolatilization process. In this phase, the carbon volatile species evolves and, successively, burns. The optimization was carried out by analyzing the chemical species generated after the devolatilization and their dependency on the main operative parameters, like temperature and pressure, which rule the process. The analysis needs acquisition of chemical and physical knowledge about the phenomenon of devolatilization and was performed with a dedicated scientific software. The kinetic parameters of the devolatilization process were obtained by assuming a single step kinetic model and by using the Arrhenius equation to correlate the data. The simulated composition of the volatile species and the definition of the fundamental parameters of the combustor, necessary to study the feasibility of a plant at the industrial size, allowed to perform a sensitivity analysis for the evaluation of the most efficient kinetic configuration of the combustion. The analysis was carried out with a commercial CFD software appropriately tailored and the results of the simulations were validated against the analysis of solid and gaseous emissions. This work allows the definition of an acceptable configuration of the combustor and provides a new starting point for the development of the mild technology applied to coal combustion

Kinetic Model of the devolatilization Process in an oxy-combustion burner

This work is focused on the study of the coal devolatilization and on its influence on the whole combustion process. The pyrolysis is particularly important since ignition is controlled by the combustion of volatiles that evolve and successively burn. The analysis of the devolatilization process has been performed with a dedicated scientific software FG-DVC (Functional Group-Depolimerization Vaporization Cross-Linking model) and supported by experimental tests with TGA (Thermogravimetry Analysis). Kinetic models of the pyrolysis have been developed and implemented into a CFD code (FLUENTTM) to analyze the burner behaviour

Prevalence of Fabry disease and GLA variants in young patients with acute stroke: The challenge to widen the screening. The Fabry-Stroke Italian Registry

Background: Fabry disease (FD) is a treatable X-linked lysosomal storage disorder caused by GLA gene variants leading to alpha-galactosidase A deficiency. FD is a rare cause of stroke, and it is still controversial whether in stroke patients FD should be searched from the beginning or at the end of the diagnostic workup (in cryptogenic strokes). Methods: Fabry-Stroke Italian Registry is a prospective, multicentric screening involving 33 stroke units. FD was sought by measuring α-galactosidase A activity (males) and by genetic tests (males with reduced enzyme activity and females) in patients aged 18-60 years hospitalized for TIA, ischemic stroke, or intracerebral hemorrhage. We diagnosed FD in patients with 1) already known pathogenic GLA variants; 2) novel GLA variants if additional clinical, laboratory, or family-derived criteria were present. Results: Out of 1906 patients, we found a GLA variant in 15 (0.79%; 95%CI 0.44-1.29) with a certain FD diagnosis in 3 (0.16%; 95%CI 0.03-0.46) patients, none of whom had hemorrhage. We identified 1 novel pathogenic GLA variant. Ischemic stroke etiologies in carriers of GLA variants were: cardioaortic embolism (33%), small artery occlusion (27%), other causes (20%), and undetermined (20%). Mild severity, recurrence, previous TIA, acroparesthesias, hearing loss, and small artery occlusion were predictors of GLA variant. Conclusion: In this large multicenter cohort the frequency of FD and GLA variants was consistent with previous reports. Limiting the screening for GLA variants to patients with cryptogenic stroke may miss up to 80% of diagnoses. Some easily recognizable clinical features could help select patients for FD screening