scholarly journals Development of a New Sensor Module for an Enhanced Fuel Flexible Operation of Biomass Boilers

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 661
Author(s):  
Martin Meiller ◽  
Jürgen Oischinger ◽  
Robert Daschner ◽  
Andreas Hornung
Keyword(s):  
Particle Size ◽  
Bulk Material ◽  
Detection System ◽  
Wood Chips ◽  
Convective Drying ◽  
Characteristic Functions ◽  
Biomass Combustion ◽  
Fuel Flexibility ◽  
Sensor Module ◽  
Over Time

The heterogeneity of biogenic fuels, and especially biogenic residues with regard to water and ash content, particle size and particle size distribution is challenging for biomass combustion, and limits fuel flexibility. Online fuel characterization as a part of process control could help to optimize combustion processes, increase fuel flexibility and reduce emissions. In this research article, a concept for a new sensor module is presented and first tests are displayed to show its feasibility. The concept is based on the principle of hot air convective drying. The idea is to pass warm air with 90 °C through a bulk of fuel like wood chips and measure different characteristics such as moisture, temperatures and pressure drop over the bulk material as a function over time. These functions are the basis to draw conclusions and estimate relevant fuel properties. To achieve this goal, a test rig with a volume of 0.038 m3 was set up in the laboratory and a series of tests was performed with different fuels (wood chips, saw dust, wood pellets, residues from forestry, corn cobs and biochar). Further tests were carried out with conditioned fuels with defined water and fines contents. The experiments show that characteristic functions arise over time. The central task for the future will be to assign these functions to specific fuel characteristics. Based on the data, the concept for a software for an automated, data-based fuel detection system was designed.

Storage Problems of Poplar Chips from Short Rotation Plantations with Special Emphasis on Fungal Development

2012 ◽  
Vol 8 (1) ◽  
pp. 123-132 ◽  
Author(s):  
Zsuzsanna Horváth ◽  
Béla Marosvölgyi ◽  
Christine Idler ◽  
Ralf Pecenka ◽  
Hannes Lenz
Keyword(s):  
Particle Size ◽  
Health Risk ◽  
Dry Matter ◽  
Ph Value ◽  
Wood Chips ◽  
Raw Material ◽  
Special Focus ◽  
Fungal Development ◽  
Short Rotation ◽  
Fungal Particles

Abstract - There are several problems in storing wood chips freshly harvested from short rotation plantations, which result in quality losses as well as in dry matter and energy losses. The factors influencing the degradation of raw material are examined in this paper with special focus on fungal development. An excessive growth of fungi is connected to dry matter losses and also to an increased health risk during raw material handling. The following factors were measured during 6 months storage of poplar wood chips depending on particle size: box temperature, moisture content, pH-value, appearance of fungi in the storage and the concentration of fungal particles in the air. The results show a close connection between particle size, temperature and attack of fungi. During the storage mesophilic and termophilic species of the genera Alternaria, Aspergillus, Cladosporium, Mucor and Penicillium appeared. The concentration of fungal particles is the highest for fine chips and decreases in bigger particles. There was a special focus on the investigation of the properties of coarse chips (G 50), which represent a good compromise between handling, storage losses and health risk due to fungal development.

Modelling Particle Size Distribution of Residual Fly Ash from Pulverized Biomass Combustion

2021 ◽  
Vol 15 (1) ◽  
pp. 75-82
Author(s):  
Mingzi Xu ◽  
Changdong Sheng
Keyword(s):  
Particle Size ◽  
Fly Ash ◽  
Simple Model ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Particle Shape ◽  
Great Influence ◽  
Biomass Combustion ◽  
Ash Formation ◽  
Residual Ash

The present work aims to develop a simple model for describing the particle size distribution (PSD) of residual fly ash from pulverized biomass combustion. The residual ash formation was modelled considering the mechanism of fragmentation and coalescence. The influences of particle shape and stochastic fragmentation on model description of the PSD of the fly ash were investigated. The results showed that biomass particle shape has a great influence on the model prediction, and a larger fragmentation number is required for cylindrical particles than that for spherical particles to get the same PSD of fly ash, and the fragment number of the particles increases with the shape factor increasing. For pulverized biomass with a wide size distribution, the model predicted ash PSD considering the stochastic fragmentation is very similar to that assuming uniform fragmentation. It implies that the simple model assuming uniform fragmentation is applicable for predicting fly ash size distribution in practical processes where biomass particles have a wide range of sizes. For the fuel with a narrower initial PSD, the stochastic fragmentation model generally predicts a coarser PSD of the residual ash than assuming uniform fragmentation. It means the stochastic fragmentation is of great influence to be considered for accurate description of ash formation from the fuel with a narrow PSD.

scholarly journals RESEARCH OF THE EJECTING PROPERTIES OF A POLYFRACTION BULK MATERIAL FLOW

2018 ◽  
Vol 3 (3) ◽  
pp. 46-51
Author(s):  
Евгений Попов ◽  
Evgeniy Popov
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Material Flow ◽  
Bulk Material ◽  
Aerodynamic Resistance ◽  
Average Diameter ◽  
Resistance Coefficient ◽  
Free Falling ◽  
The Given

This work is aimed at confirming the adequacy of the probabilistic and statistical approach to determining the aerodynamic resistance coefficient of particles in a flow of the free falling polyfractional material, suggested by the author. The aerodynamic resistance coefficient of particles in a flow of falling material is defined by calculating the probability of finding particles out of air shadows of the neighboring particles. The laboratory experiment was performed on the offered experimental samples of bulk materials having different particle size distribution, but the identical average diameter of particles. The design of a laboratory experimental installation which allows determining the consumption of air, ejected by a polyfractional material flow, was described. The amount of the air, ejected with experimental samples, depends on their particle size distribution that confirms the insufficiency of describing the properties of bulk material only with the average diameter value. The given comparison of results of the analytical calculations with experimental data shows the reliability and adequacy of the calculated values.

DC and AC Measurements of Magnetite Nanoparticulates and Implications for Nonlinear Response

2008 ◽  
Vol 1138 ◽  
Author(s):  
Silvia Liong ◽  
Ricky Lamar Moore
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Polymer Composites ◽  
Magnetic Measurements ◽  
Bulk Material ◽  
Low Frequency ◽  
Anisotropy Field ◽  
Coaxial Line ◽  
Magnetic Data ◽  
Order Of Magnitude

AbstractThis paper discusses preparation, characterization and measurement of linear DC and AC magnetic properties of magnetite (Fe3O4) nanoparticles (size ranges of 7-50 nm and 5 microns) and polymer composites of those particulates. Selected data and analysis are taken from the PhD thesis of Liong [1]. The goal of this research is to obtain magnetic data, specifically magnetization, anisotropy and coercivity as functions of particle size. These will be used as inputs to non linear magnetic simulations and in planning for future nonlinear magnetic measurements. Magnetite nanoparticles were synthesized by chemical coprecipitation, a method that allowed for the production of samples in gram quantities. Vibrating sample magnetometry was used to measure the room-temperature DC magnetization and coercivity of the particulates. Coaxial line impedance measurements were used to measure low frequency and dispersive AC permeability of Fe3O4–polymer composites from 1 Megahertz to 10 Gigahertz. AC data are applied to infer particulate magnetic susceptibility and anisotropy field change with particle size. Particle size was calculated from XTD data and supported by TEM images.Measured DC saturation magnetization and coercivity decreased with particle dimension while anisotropy was calculated to increase. Magnetization data are consistent with models that calculate nanoparticle magnetization as a volumetric average of a spherical bulk material core and a passive outer shell. The shell thickness was calculated at 0.84 nm, very near one lattice constant of bulk Fe3O4, 0.8394 nm. Composites containing particulate volume fractions less than 20% were fabricated. Effective media theory was applied to measured AC composite permeability to extract particle magnetic properties and thereby anisotropy field, which increased by an order of magnitude from the bulk. Permeability decreased with particulate size.

THE INFLUENCE OF THE DRYING MEDIUM ON HIGH TEMPERATURE CONVECTIVE DRYING OF SINGLE WOOD CHIPS

1997 ◽  
Vol 15 (6-8) ◽  
pp. 1801-1813 ◽  
Author(s):  
Anders Johansson ◽  
Anders Rasmuson
Keyword(s):  
High Temperature ◽  
Wood Chips ◽  
Convective Drying

scholarly journals A Protocol to Quantify the Reactivity of Carbonate Lime for Horticultural Substrates

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1124E-1125
Author(s):  
Jinsheng Huang ◽  
Paul R. Fisher ◽  
William R. Argo
Keyword(s):  
Particle Size ◽  
Reaction Rates ◽  
Rapid Screening ◽  
Reactivity Index ◽  
Analytical Test ◽  
Horticultural Practice ◽  
Ph Level ◽  
Time Required ◽  
Lime Reactivity ◽  
Over Time

Lime sources vary in their reactivity depending on particle size, surface area and crystalline structure, and chemical composition. Current horticultural practice for testing lime reactivity and the appropriate lime rate is through batch trials where lime is incorporated into growing media. Our objective was to test a laboratory approach that would provide a rapid analytical test on reactivity of lime sources, and could eventually be applied to measuring unreacted (residual) lime in container media. Four moles HCl was added to a lime sample, and the volume of CO2 released over time was measured in a burette. Three lime types were tested, including reagent grade CaCO3, and two pulverized dolomitic limestones used in horticultural media. 100% of CaCO3 reacted in less than a minute after acid addition, whereas only 79.8% and 49.5% of the two commercial lime samples had reacted after 10 minutes. The time required for 50% of the two commercial lime samples to react was 5 and 10 minutes, respectively, whereas it took 20 and 60 minutes, respectively, for 95% neutralization. Reaction rates in the laboratory test correlated with the time required to achieve a stable pH level when limes were incorporated into a peat substrate. The reagent-grade CaCO3 raised pH more rapidly (within 7 days) and to a higher level (maximum pH 7.5 at 9 g of lime per liter of peat) compared with the dolomitic lime sources. It may be possible to establish a lime reactivity index, for example, based on CO2 release after 10 minutes, and thereby provide a rapid screening of limes. Further gasometric analysis of lime types used in horticultural substrates is therefore needed.

scholarly journals InterSpot: Interactive Spammer Detection in Social Media

2019 ◽  
Author(s):  
Kaize Ding ◽  
Jundong Li ◽  
Shivam Dhar ◽  
Shreyash Devan ◽  
Huan Liu
Keyword(s):  
Social Media ◽  
Learning Process ◽  
Interactive Learning ◽  
Detection System ◽  
Feedback Information ◽  
Detection Model ◽  
Empirical Success ◽  
Detection Strategy ◽  
Current Detection ◽  
Over Time

Spammer detection in social media has recently received increasing attention due to the rocketing growth of user-generated data. Despite the empirical success of existing systems, spammers may continuously evolve over time to impersonate normal users while new types of spammers may also emerge to combat with the current detection system, leading to the fact that a built system will gradually lose its efficacy in spotting spammers. To address this issue, grounded on the contextual bandit model, we present a novel system for conducting interactive spammer detection. We demonstrate our system by showcasing the interactive learning process, which allows the detection model to keep optimizing its detection strategy through incorporating the feedback information from human experts.

Physical properties of Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 211-217 ◽  
Author(s):  
Jeffrey N. Cuzzi
Keyword(s):  
Particle Size ◽  
Radio Occultation ◽  
Particle Density ◽  
Bulk Material ◽  
Small Particles ◽  
Water Ice ◽  
Saturn’S Rings ◽  
Saturn's Rings ◽  
Classical Ring ◽  
Sharp Cutoff

A review is given of important features of the rings, touching only lightly on aspects covered by other speakers (Spokes, E ring). This extended abstract will only convey the high points of the talk.Most of the material in Saturn's rings is concentrated in the B ring, with a lesser amount in the A ring and only small amounts in the C ring and Cassini Division. There is a very different character to these classical ring regions; the C and Cassini particles are darker and more neutral in color; (Smith et al. 1981, 1982). The A and B regions contain nearly all of the “small” particles, from microns to millimeters. Overall, however, the particles are fairly well characterized by Voyager radio occultation results as roughly following an r-3powerlaw between about 1 cm and a few meters (Tyler et al. 1982, Marouf et al. 1982). A fairly sharp cutoff in the size distribution is seen at radii varying with location from about 1 to about 5 meters. The material of the ring particles is probably mostly water ice (see e.g., Pollack 1975) but the redness of the rings requires the presence of minor constitutents. Combinations of ground-based radar and radio emission observations (Pollack 1975, Cuzzi and Pollack 1978; Pettengill, this issue) strongly indicate that the non-icy component comprises a small fraction of the total bulk material. In fact, mass densities derived from density waves (e.g. Holberg et al. 1982) and CRAND measurements (Cooper et al. 1982) combined with Voyager particle size measurements indicate a particle density more like that of snow or frost than that of pure ice.

THE RELEASE OF MONOTERPENES DURING CONVECTIVE DRYING OF WOOD CHIPS

1998 ◽  
Vol 16 (7) ◽  
pp. 1395-1428 ◽  
Author(s):  
ANDERS JOHANSSON ◽  
ANDERS RASMUSON
Keyword(s):  
Wood Chips ◽  
Convective Drying
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