Marco Mancini

Marco Mancini
Technische Universität Clausthal | TUC · Department of Energy Process Engineering and Fuel Technology

Dr.Ing- habil.

About

49
Publications
6,253
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1,232
Citations
Additional affiliations
February 2002 - present
Technische Universität Clausthal
Position
  • Head of the Mathematical modelling Group

Publications

Publications (49)
Article
The subject of this work is the mathematical modelling of a counter-current moving-bed gasifier fuelled by wood-pellets. Two versions of the model have been developed: the one-dimensional (1D) version-solving a set of Ordinary Differential Equations along the gasifier height-and the three-dimensional (3D) version where the balanced equations are so...
Article
Full-text available
Seven biomass fuels were fired to determine the relationship between the ash deposition rate and the probe/ash-particle temperature varied in the 115–1200 °C range. The experiments were carried out at deposition-probe Reynolds number in the 40–60 range and Stokes number in the 0.8–1.9 range. The relationship between the deposition rate and probe/as...
Article
In our previous publications we have presented revised and extended versions of Hottel’s total emissivity charts for water vapor, carbon monoxide, carbon monoxide and their mixtures. In applications, not only emissivity but also absorptivity is required. In 1935, Hottel and Mangelsdorf produced formulae for calculating total absorptivity using tota...
Article
Full-text available
Gaseous flames and pulverized coal flames are considered to examine relationships between lab-scale flames, semi-industrial scale and industrial-scale flames. The experimental data spans the thermal input range from the lowest scale of 30 kW to the largest of 12 MW with several intermediate scales. The primary questions are whether effects observed...
Article
Gray gas emissivities of water vapor, carbon dioxide, and carbon monoxide are needed in many engineering calculations to determine radiative heat fluxes in high-temperature processes. In this work we provide (a) an EXCEL program (see Supplementary Material) that predicts total gas emissivities for H2O-CO2-CO-N2 mixtures and (b) a set of graphs for...
Article
Full-text available
Entrained flow gasification is a promising process for the conversion of low-grade feedstock, e.g. highly viscous slurries and suspensions with a significant content of solid particles, to high quality fuels. A major scientific challenge is the prediction of the physical and chemical phenomena occurring in such high-temperature and high-pressure mu...
Article
CFD (RANS based) simulations of REGA-1 experimental campaign concerning gasification of glycol in an oxygen-nitrogen mixture have been carried out. The reacting flow-field has been computed using a number of turbulence models while turbulence-chemistry interactions have been modeled using either the Eddy Dissipation Concept (EDC) or the presumed PD...
Article
Full-text available
Three coordinated papers are presented concerning entrained flow gasification of a liquid fuel under atmospheric conditions. The work is based on a detailed mapping of process parameters inside the entrained flow gasifier and at the gasifier outlet. In this paper the experimental setup and the experimental data are reported. Mono ethylene glycol (M...
Article
Calculations of total gas emissivities of gas mixtures containing several radiatively active species require corrections for band overlapping. In this paper, we generate such overlap correction charts for H2O−CO2−N2,H2O−CO−N2, and CO2−CO−N2 mixtures. These charts are applicable in the 0.1 to 40 bar total pressure range and in the 500 K to 2500 K te...
Article
A two-dimensional time-dependent model for mathematical description of the oxidation process of a coal-char particle placed in an oxidizer stream has been developed. The model is used to simulate the oxidation process of a 5.2 mm char-particle for which the kinetic parameters for heterogeneous reactions have been measured. The initial morphology ha...
Article
The line-by-line procedure developed in the associated paper (Part A ) has been used to generate the total emissivity chart for pure CO and mixtures at 1 bar total pressure, in the 300 to 3000 K temperature and 0.01 to 3000 bar cm pressure path length range. Methods of scaling the emissivity to pressures different to 1 bar, in the range 0.1 to 40 b...
Article
A line-by-line procedure has been developed for calculating the effective band width (band absorptance) of both the fundamental and the first overtone bands of carbon monoxide. The procedure is based on HITEMP-2010 data base and each absorption line has been truncated to remedy the sub-Lorentzian behavior in the line wings. The truncation criterion...
Chapter
Vorwort Der Flammentag ist das etablierte Forum für den Austausch von Wissenschaft und Praxis über die neuesten Betriebs- und Forschungsergebnisse auf dem Gebiet der Verbrennung und der Feuerungen. Teilnehmer aus Industrie und Hochschule treffen sich im zweijährigen Turnus auf dieser Veranstaltung, um bei Fachvorträgen, Posterpräsentationen und Fac...
Article
Hottel’s water vapor emissivity chart and the pressure correction chart have been re-created using the most recent HITEMP-2010 data base to provide more accurate values. Hottel’s standard emissivity has been redefined in order to produce smooth and accurate graphs and correlations. The new charts allow for calculating the water vapor emissivities a...
Article
This work combines experimental and computational fluid dynamics (CFD) results to derive global kinetics for biomass (pine wood) devolatilization during heating rates on the order of 105Ks-1, bulk flow peak temperatures between 1405 and 1667K, and particle residence times below 0.1s. Experiments were conducted on a laboratory laminar entrained flow...
Article
This work aims to provide an accurate and simple model, predicting the time dependent devolatilization of woody biomass at conditions (Tgas < 2000 K) and particle sizes (<2 mm) relevant to suspension fired boilers. The zero dimensional model is developed from reference calculations with a one-dimensional heat transport model coupled with a drying a...
Chapter
This chapter deals with radiative transfer in combustion systems, where laminar or turbulent reactive flows are present, and radiation is often an important heat transfer mode. The reactive medium emits, absorbs and, if solid particles are present (e.g., pulverized coal, fly ash), scatters radiation. It is referred to as a participating medium, sin...
Article
Measurements of fly ash deposition in a 15 kW pulverized coal jet flame and CFD-based mathematical modeling have been performed. The deposits have been collected at two ports at particle Stokes numbers in the 0.02-0.34 range and particle kinetic energies not larger than 2×10-9 J. Inertial impaction and thermophoresis have been identified as main me...
Article
The Grain-Thermo-Balance (GTB) rig was built for generation of the char, at high heating rates, and for experimental determination of its oxidation rates. A zero-dimensional mathematical model for calculating oxidation rates of millimeter-size char particles was developed to serve as a char particle sub-model in a CFD-based software for predicting...
Article
The objective of the work is validation of HITEMP-2010 at atmospheric pressures and temperatures reaching 1770K. To this end, spectral transmissivities at 1 cm−1 resolution and excellent signal-to-noise-ratio have been measured for 22 mixtures. In this paper we consider the 450 cm−1-7600 cm−1 spectral range. The LbL calculations and their compariso...
Article
The objective of this paper is twofold: to summarise the basic knowledge on kinetics of heterogeneous reactions and to clarify several misconceptions concerning both derivation and usage of expressions for calculating char oxidation rates. This paper is concerned with char reactions only; coal devolatilization is not considered although it may affe...
Article
The pioneering work of Hottel and co-workers produced emissivity charts for carbon dioxide, water vapor and their mixtures. Besides the work of Hottel, Leckner’s analytical expressions for predicting gas emissivities, published in 1972, are widely used. In this work we produce more accurate charts applicable to 1bar pressure and produce graphs up t...
Article
A comparison of different models for predicting band emissivity of CO2 and H2O at temperatures up to 1550 K is presented. The calculations do not contain line-by-line databases only; a narrow-band as well as a wide-band model are also included. The main objective of this work is in comparing the spectral transmissivity and band emissivity values ob...
Article
The objective of this paper is to identify the requirements for accurate predictions of impaction efficiency on tubes using Reynolds Averaged Navier–Stokes (RANSs) approach. Flows which pass a cylinder have been computed using steady-state and time-dependent simulations with emphasis on numerical related errors, boundary layer and turbulence modell...
Article
Biomass and low rank fuel gasification is a very promising process for conversion of fuels to a high quality fuel (Syngas). In the present paper research work on the design of a high pressure entrained flow gasifier for biomass based fuels is shown.Atomization quality of twin fluid nozzles as a function of gas velocity and reactor pressure is analy...
Article
The objective of this paper is to examine several approaches for predicting the ash behaviour using Computational Fluid Dynamics (CFD). The emphasis is placed on details of the sub-models used. In models that aim at predicting the temperature–time history of fuel particles, from the injection position to the deposit surface, the information about t...
Article
Technical and ecological aspects of implementation of High Temperature Air Combustion to power station boilers fired with pulverized coal have been considered. Several boiler concepts have been examined in the context of the following three key points: existence of an intensive in-furnace recirculation, homogeneity of both the temperature and the c...
Article
MILD (flameless) combustion is a new rapidly developing technology. The IFRF trials have demonstrated high potential of this technology also for N-containing fuels. In this work the IFRF experiments are analyzed using the CFD-based mathematical model. Both the Chemical Percolation Devolatilization (CPD) model and the char combustion intrinsic react...
Article
Blends of a South African bituminous “Middleburg” coal and alternative fuels (sewage sludge, saw-dust and refuse derived fuel) have been fired in the slagging reactor to examine the effect of the added fuel on slagging propensity of the mixtures. Two ceramic deposition probes have been used to investigate the initial stages of slagging at 1300 °C a...
Article
A small amount of pulverised coal is injected into an isothermal chamber filled up with stagnant air at ambient temperature. As the time elapses the particles disperse into the chamber volume. The objective is to simulate this dispersion using a time-dependent particle tracking procedure. The results of the simulations are validated using a video s...
Article
A further analysis of the IFRF semi-industrial-scale experiments on flameless (mild) combustion of natural gas is carried out. The experimental burner features a strong oxidizer jet and two weak natural gas jets. Numerous publications have shown the inability of various RANS-based mathematical models to predict the structure of the weak jet. We hav...
Article
Blends of a South African bituminous "Middleburg" coal and alternative fuels (sewage sludge, saw dust and refuse derived fuel) have been fired in the slagging reactor to examine the effect of the added fuel on slagging propensity of the mixtures. Two ceramic deposition probes have been used to investigate the initial stages of slagging at 1300°C an...
Article
Applications of HTAC technology to supercritical power station boilers fired with pulverized coal have been considered. Several particular boiler designs have been analysed in the context of the three key points: intensive in-furnace recirculation, uniformity of both the temperature and chemical species fields, and heat fluxes uniformity. The CFD-b...
Article
This paper deals with the technology of burning natural gas with combustion air preheated to 1300 degreesC. The objective of this work is to assess the potential of several combustion models and NOx postprocessors for their abilities to predict NOx emissions. The steady-state computational results have been compared both with in-furnace measurement...
Article
Full-text available
Combustion of fuels with high-temperature air and large quantities of flue gas is perhaps the most rapidly developing combustion technology of the last decade. The technology, when applied together with an efficient heat recovery system, offers substantial energy savings and drastic reductions in CO 2 , CO and NOx emissions. The objective of our wo...
Article
Full-text available
The authors propose a concept of HTAC technology application to the power boilers fired with pulverized coal. So far, HTAC technology was implemented mainly in industrial furnaces fired with gaseous fuels or light oils. In order to investigate the HTAC boiler, several series of numerical simulations have been performed using FLUENT code. A speciall...

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Projects

Projects (5)
Project
In this project, the overall process of a compressed air storage power plant has to be developed and analyzed. Hydrogen is supposed to be used as a fuel on the one hand to allow a more efficient operation with reduction of greenhouse gas emissions and on the other hand to enable a more economically advantageous operation. The analysis includes three simulation levels of different depth starting from the thermodynamic simulation of the entire plant, through a CFD analysis of the stability of the flame until the analysis of the marketing of the clean generated electricity.
Archived project
Understanding of solid fuel combustion, gasification and pyrolysis. Main Goal is the implementation of models into CFD software.