1,721,552 research outputs found
Sponges from African inland waters: The genus Eunapius (Haplosclerida, Spongillina, Spongillidae)
No full text
Experimental investigation and numerical simulation of CO to CO2 conversion and hydrogen production from water gas shift reaction,
No full textWater gas shift reaction (WGSR) is an important chemical process for enhancing the conversion of the syngas carbon monoxide contents into hydrogen by means of steam, in coal gasification power plants integrated with Carbon Capture and Storage (CCS) technologies.
This paper concerns an experimental investigation and numerical simulation on carbon monoxide conversion and hydrogen generation from WGSR using a small scale experimental apparatus.
The laboratory test rig is based on two packed-bed catalytic reactors in series to be operated at different temperatures. It has been designed for testing WGSR processes using different catalysts, at varying syngas temperatures (from 350 to 500 °C for the high temperature reactor and from 180 to 250 °C for the low temperature reactor) and initial syngas compositions (up to 100% of dry CO fraction). The system has been instrumented for temperature, flow rate and gas composition measurements, and can operate both in a two-stage or in a single-stage mode.
This paper investigates the performance of the WGSR affected by various and important parameters, like catalyst type (Fe/Cr or Pt/Al for high temperature and Cu/Zn or Pt/Al for low temperature), residence time of reactants in the catalyst bed, reaction temperature and H2O/CO ratio. The experimental results are supported by numerical analyses, based on equilibrium and kinetic models for the WGSR simulations
Recent advances of non-lamellar lyotropic liquid crystalline nanoparticles in nanomedicine
Full text linkNon-lamellar lyotropic liquid crystalline nanocarriers such as hexosomes and cubosomes are relatively unexplored lipid-based nanoparticles in nanomedicine that can be specifically formulated to match specific medical applications, thus exploiting the majority of the possible routes of administrations. A growing number of papers demonstrate intriguing features that make them good candidates as nanocarriers for therapeutically active molecules or imaging probes. Yet, important aspects, including pharmacokinetics, hemocompatibility, toxicity, and delivery properties, are not completely clarified, so that their full potential as nanomedicines remains to be assessed. This article reviews recent advances in the field and suggests possible new routes forward
Studio sperimentale e simulazione numerica del processo WGSR di conversione del CO in CO2 per l’arricchimento in H2 di syngas da gassificazione del carbone e reforming di combustibili fossili
No full textThe water gas shift reaction (WGSR) is an important chemical process for enhancing the conversion of syngas carbon
monoxide content into hydrogen by means of steam in coal gasification power plants integrated with Carbon Capture and
Storage (CCS) technologies.
This paper concerns an experimental investigation and numerical simulation on carbon monoxide conversion and hydrogen
generation from WGSR using a small scale experimental apparatus designed and built at the Department of Mechanical
Engineering, University of Cagliari.
The laboratory test rig is based on two packed-bed catalytic reactors in series to be operated at different temperatures. It is
designed for testing WGSR processes using different catalysts at varying syngas temperatures (from 300 to 500°C for the high
temperature reactor and from 180 to 250°C for the low temperature reactor) and initial syngas compositions (up to 100% of dry
CO fraction).The system is instrumented for temperature, flow rate and gas composition measurements, and can operate both
in a two-stage or single-stage mode.
This paper investigates the performance of the WGSR affected by various and important parameters, such as catalyst type
(Fe/Cr or Pt/Al for high temperature and Cu/Zn or Pt/Al for low temperature), operating mixture composition, residence time
of reactants in the catalyst bed, reaction temperature and H2O/CO ratio. The experimental results are supported by numerical
analyses based on equilibrium and kinetic models for WGSR simulations
Comprehensive CFD Model of Air-Blown Coal-Fired Updraft Gasifier”
No full textA comprehensive CFD model has been developed to simulate the gasification process within an air-blown
updraft coal gasifier. Updraft fixed bed gasification processes are characterized by complex behavior,
since they involve different space- and time-dependent sub-processes where coal preheating, drying,
de-volatilization and char reactions take place. Simplified models, such as non-dimensional ones, useful
for preliminary gross mass and energy balance, are unable to correctly simulate the overall gasification
phenomena and more sophisticated approaches are required.
In particular, CFD models could be used to describe in a detailed way the complex time- and spacedependent
phenomena involved in the gasification process. Considering the high volume fraction of
the solid phase, close to the packing condition, the Euler–Euler approach is required to model this multiphase
flow. The solid phase is considered as a continua according to the kinetic and plastic theory of
granular flows.
The operation of a Wellman–Galusha gasifier is investigated, considering a non-continuous loading of
coal and extraction of the ash, with the aim of characterizing the space- and time-dependent behavior of the process
Two-dimensional CFD model of air-blown coal-fired updraft gasifier
No full textA CFD two-dimensional model has been developed for simulating the gasification process
within an air-blown updraft coal gasifier. Fixed-bed gasification processes are characterized by a
complex behaviour since they involve different space- and time-dependent sub-processes where
coal preheating and drying, devolatilization and char reactions take place. Simplified models,
such as non-dimensional ones, useful for preliminary gross mass and energy balance, are unable
to correctly simulate in detail the overall gasification phenomena and more sophisticated CFD
models are required for their understanding. The complexity of the physical processes in the
updraft gasifier is compounded by the multiphase nature of the flow and by the interphase processes.
Considering the high volume fraction of the solid phase, close to the packing condition,
the Euler-Euler approach is required to model the interpenetrating phases. The solid phase is
considered as a continuum according to the kinetic theory of granular flows. The aim of this
work is to characterize the spatial and time-dependent behaviour of updraft gasifiers in terms of
gas velocity, temperature and species concentration. In particular, the dynamic behaviour of the
process is fundamental to understanding the time required for complete coal conversion
Experimental investigation and numerical simulation of CO to CO2 conversion for hydrogen enrichment of syngas from an air-blown fixed bed up-draft coal gasifier
No full textThe water gas shift reaction (WGSR) is an important chemical process for enhancing the conversion of the syngas carbon monoxide contents into hydrogen by means of steam, in coal gasification power plants integrated with Carbon Capture and Storage (CCS) technologies.
The carbon monoxide conversion and hydrogen generation may be based on multi-step reactors operating at decreasing temperatures, using highly efficient catalysts and integrated with membranes for hydrogen separation.
This paper concerns an experimental investigation and numerical simulation on carbon monoxide conversion and hydrogen generation from water gas shift reaction using a small scale experimental apparatus based on a two-stage catalytic water-gas reactor.
The main aim of the experimental apparatus is to support the design, optimization and operation of a pilot-scale plant for high sulphur (Sulcis) coal gasification, gas cleaning and treatment, CO2 separation, hydrogen and electricity production, recently installed at the Sotacarbo Research Centre.
The laboratory test rig is based on two packed-bed reactors in series to be operated at different temperatures. It has been instrumented for temperature, flow rate and gas composition measurements, and can operate both in a two-stage or in a single-stage mode.
The system has been designed for testing WGSR processes using different catalysts and at varying syngas temperatures (from 300 to 500 °C for the high temperature reactor and from 180 to 250 °C for the low temperature reactor) and initial syngas compositions (up to 100% of dry CO fraction).
This paper investigates the characteristics of carbon monoxide conversion and hydrogen generation from the WGSR. The dry fuel gas mixture composition taken as the baseline composition for the laboratory test-rig, is similar to the expected fuel gas composition at the Sotacarbo gasifier outlet, produced by gasification of a mix of high sulphur (Sulcis-type) and low sulphur (South African-type) coal. This mixture is composed simply of H2, CO, CO2 and N2. The experimental investigation evaluates the performance of WGSR affected by various and important parameters, like catalyst type (Fe/Cr or Pt/Al for high temperature and Cu/Zn or Pt/Al for low temperature), residence time of reactants in the catalyst bed, reaction temperature and CO/steam ratio. The experimental results are supported by numerical analyses, based on equilibrium and kinetic models for the WGSR simulations
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