Numerical Modeling of a Biomass Pellet Domestic Boiler

Abstract:In this work, fouling and bottom ash were collected from a low-power boiler after wood pellet combustion and studied using several analytical techniques to characterize and compare samples from different areas and determine the suitability of the analysis techniques employed. TGA results indicated that the fouling contained a high amount of organic matter (70%). The XRF and SEM-EDS measurements revealed that Ca and K are the main inorganic elements and exhibit clear tendency in the content of Cl that is negligible in the bottom ash and increased as it penetrated into the innermost layers of the fouling. Calcite, magnesia and silica appeared as the major crystalline phases in all the samples. However, the bottom ash was primarily comprised of calcium silicates. The KCl behaved identically to the Cl, preferably appeared in the adhered fouling samples. This salt, which has a low melting point, condenses upon contact with the low temperature tube and played a crucial role in the early stages of fouling formation. XRD was the most useful technique applied, which provided a semi-quantitative determination of the crystalline phases. FTIR was proven to be inadequate for this type of sample. The XRF and SEM-EDS, techniques yield similar results despite being entirely different.

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“…Due to this, the burnout distance or time is minimal. In fact, sometimes the flame quenches within the water tubes [37].…”

Section: Fuel Facility and Samplesmentioning

confidence: 99%

A Comparative Study of Fouling and Bottom Ash from Woody Biomass Combustion in a Fixed-Bed Small-Scale Boiler and Evaluation of the Analytical Techniques Used

et al. 2015

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“…In the second plant, a boiler, coupled with an absorption machine, provides both heating and cooling, using local wood-based biomass (Figure 3b). When compared to fossil fuels, biomass presents a number of advantages: low sulfur and nitrogen content, generating much lower emissions of NO x and SO 2 than that of conventional fossil fuels; the ash content is very low (<1% in most wood samples); they are a cheap energy source [34][35][36][37][38]. Nowadays, biomass is one of the major energy sources, providing approximately 14% of the world energy requirements, varying from 9% to 14% of the total energy supply in industrialized countries and up to 35%-40% in developing countries [34].…”

Section: The Pilot Heating/cooling System Ideasmentioning

confidence: 99%

Development of Innovative Heating and Cooling Systems Using Renewable Energy Sources for Non-Residential Buildings

et al. 2013

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Industrial and commercial areas are synonymous with high energy consumption, both for heating/cooling and electric power requirements, which are in general associated to a massive use of fossil fuels producing consequent greenhouse gas emissions. Two pilot systems, co-funded by the Italian Ministry for the Environment, have been created to upgrade the heating/cooling systems of two existing buildings on the largest industrial estate in Umbria, Italy. The upgrade was specifically designed to improve the system efficiency and to cover the overall energy which needs with renewable energy resources. In both cases a solar photovoltaic plant provides the required electric power. The first system features a geothermal heat pump with an innovative layout: a heat-storage water tank, buried just below ground level, allows a significant reduction of the geothermal unit size, hence requiring fewer and/or shorter boreholes (up to 60%-70%). In the other system a biomass boiler is coupled with an absorption chiller machine, controlling the indoor air temperature in both summer and winter. In this case, lower electricity consumption, if compared to an electric compression chiller, is obtained. The first results of the monitoring of summer cooling are presented and an evaluation of the performance of the two pilot systems is given.

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“…As in similar works [11,12], the steady-state governing equations were solved using the SIMPLE algorithm; the spatial discretization was solved using the second-order upwind method for the momentum, energy and radiation; and the pressure was determined using PRESTO. The continuity, momentum and energy of the gas phase were modeled according to the standard CFD procedures, which are well documented [13] and will not be discussed in this paper.…”

Section: Gas Phasementioning

confidence: 99%

“…Previous works [11,12] were based on the assumption that radiation from the combustion chamber has a strong influence on the biomass decomposition. These works model a zero-dimensional bed in which the radiation of the flame was considered as an input variable used in performing mass and energy balances and generating the variables necessary to simulate combustion in the framework.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Effect of Water Temperature on Domestic Biomass Boiler Performance

et al. 2012

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This paper presents a methodology to simulate the combustion of fixed beds of biomass particles using computational fluid dynamics (CFD) techniques. The models presented were used in the simulation of a domestic pellet boiler working under operating conditions and the model predictions were compared with measurements of heat transfer, temperature and species concentration. The same procedure was then used to simulate the same domestic boiler working with different values of water temperature and the influence of water temperature variations on the main variables was analyzed.Keywords: simulation; CFD; combustion; biomass; boiler Mass fraction of species generated in the bed [-] Void fraction [-] CO to CO 2 ratio [-] Air excess ratio [-] Dynamic viscosity [kg mStoichiometric coefficient of the pellet consumption [-] Mass fraction in volatile gas [-] Sphericity [-] ′′′

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Numerical Modeling of a Biomass Pellet Domestic Boiler

Cited by 102 publications

References 34 publications

A Comparative Study of Fouling and Bottom Ash from Woody Biomass Combustion in a Fixed-Bed Small-Scale Boiler and Evaluation of the Analytical Techniques Used

A Comparative Study of Fouling and Bottom Ash from Woody Biomass Combustion in a Fixed-Bed Small-Scale Boiler and Evaluation of the Analytical Techniques Used

Development of Innovative Heating and Cooling Systems Using Renewable Energy Sources for Non-Residential Buildings

Simulation of the Effect of Water Temperature on Domestic Biomass Boiler Performance

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