A review on the utilization of fly ash

This chapter introduces the finite element method (FEM) as a tool for solution of classical electromagnetic problems. Although we discuss the main points in the application of the finite element method to electromagnetic design, including formulation and implementation, those who seek deeper understanding of the finite element method should consult some of the works listed in the bibliography section.

Introduction to the Finite Element Method

Modeling chemical and physical processes of wood and biomass pyrolysis

In this review, we summarize the knowledge of the production and properties of charcoal that has been accumulated over the past 38 millenia. The manipulation of pressure, moisture content, and gas flow enables biomass carbonization with fixed-carbon yields that approachor attainthe theoretical limit after reaction times of a few tens of minutes. Much of the heat needed to carbonize the feed is released by vigorous, exothermic secondary reactions that reduce the formation of unwanted tars by augmenting the charcoal yield in a well-designed carbonizer. As a renewable fuel, charcoal has many attractive features:  it contains virtually no sulfur or mercury and is low in nitrogen and ash; it is highly reactive yet easy to store and handle. Carbonized charcoal can be a good adsorbent with a large surface area and a semimetal with an electrical resistivity comparable to that of graphite. Recent advances in knowledge about the production and properties of charcoal presage its expanded use as a renewable fuel, red...

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The Art, Science, and Technology of Charcoal Production†

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A comprehensive review on the applications of coal fly ash

Coal pyrolysis: Experiments, kinetic rates and mechanisms

A review of the kinetics of the nitric oxide-carbon reaction

The thermochemistry of cellulose pyrolysis has been studied by a combination of differential scanning calorimetry and thermogravimetric analysis. Additionally, the vapor pressure and heat of vaporization of levoglucosan have been determined by an effusion method. The cellulose pyrolysis has been carried out under inert gas at heating rates from 0.1 to 60 K/min. The main cellulose thermal degradation pathway is endothermic, in the absence of mass transfer limitations that promote char formation. The endothermicity is estimated to be about 538 J/g of volatiles evolved. It is concluded that this endothermicity mainly reflects a latent heat requirement for vaporizing the primary tar decomposition products. Pyrolysis can be driven in the exothermic direction by char-forming processes that compete with tar-forming processes. The formation of char is estimated to be exothermic to the extent of about 2 kJ/g of char formed. Low heating rates, in concert with mass transfer limitations, serve to drive the pyrolysis ...

Thermal Effects in Cellulose Pyrolysis: Relationship to Char Formation Processes

The kinetics of cellulose pyrolysis have received considerable attention during the past few decades. Despite intensive study, there remains controversy in the literature even on a topic as basic as the global kinetics of pyrolysis. The reported kinetics have been reconsidered in light of new experimental results that suggest a simple resolution to that part of the controversy concerning the activation energy of pyrolysis. It appears that the reported kinetics are sensitive to the heating rate employed in the experiments used to deduce them. Experiments in which the cellulose is rapidly heated to above 600 K give apparently ``low`` activation energies, mainly between about 140 and 155 kJ/mol, in the case of the material studied here. This applies to both ``isothermal`` and high heating rate temperature-ramp experiments. Alternatively, cellulose heated more slowly to temperatures below 600 K appears to lose mass with an activation energy that is about 218 kJ/mol, The mathematical modeling of processes involving pyrolysis of cellulosic materials (e.g., biomass conversion processes, fire phenomena) can be strongly influenced by which kinetics are assumed, since the kinetic constants from one regime will not accurately predict mass loss in the other.

Cellulose Thermal Decomposition Kinetics: Global Mass Loss Kinetics

Previous research at M.I.T. on coal pyrolysis in inert gas and in hydrogen was based on the measurement of coal weight loss, referred to as volatiles yield. The work is now being extended to include volatiles composition measurements and elemental analysis of the char for the same ranges of experimental conditions covered in the previous study. To this end, the previous apparatus has been modified to permit the collection and analysis of volatiles. This paper presents the first set of composition data, for lignite pyrolysis, and some initial interpretations of pyrolysis behavior in the light of the products formed. The pyrolysis of pulverized Montana lignite by time-resolved measurement of the yields and compositions of products formed under controlled temperature-time histories was studied in a captive sample apparatus. The yields of water, carbon monoxide, carbon dioxide, hydrogen, and hydrocarbon gases and light liquids were determined by gas chromatography. The yields of all the volatile products increase monotonically with temperature and approach asymptotic values at the higher temperatures.

Eric M. Suuberg

Papers

Coal pyrolysis: Experiments, kinetic rates and mechanisms

A review of the kinetics of the nitric oxide-carbon reaction

Thermal Effects in Cellulose Pyrolysis: Relationship to Char Formation Processes

Cellulose Thermal Decomposition Kinetics: Global Mass Loss Kinetics

Product Composition and Kinetics of Lignite Pyrolysis