Characterization of coal products from high temperature processing of Usibelli low-rank coals

This research project was conducted in association with Gilbert/Commonwealth Inc. as part of an overall techno-economic assessment of high temperature drying of low-rank coals. This report discusses the characteristics of the dried/pyrolyzed products of two high temperature, evaporative processes and the dried product from a hydrothermal process. The long term goal of this and other coal drying studies conducted at MIRL, was to define drying technologies that have significant and real potential to competitively move Alaska's, low-rank coals (LRCs) into the export, steam coal market of the Pacific Rim. In 1990, Japan imported 33 million metric tons (mt) of steam coal with an additional 39 million mt imported by other Far East nations(2). Australia dominates the export steam coal market to these Pacific Rim countries and exported 48 million mt in 1990 and an additional 61 million mt of metallurgical coal(2). The worldwide steam coal export market has been expanding rapidly, from 20 million mt in 1973 to 150 million mt in 1989, and is expected to double to nearly 300 million mt by the end of the century(3). Could Alaska capture only 3% of the projected new world steam coal market, which is not an unreasonable expectation, the value of the state's coal exports would soar from nominally $28 million per year to over$100 million per year. However, without development of economical methods for drying/stabilizing Alaskan LRCs, the only increase in export of Alaskan coals may be from the few "higher rank" coals within a "reasonable" transport range of the existing Alaska rail system or tidewater. Presently the coal from the Usibelli Coal Mine is the only low-rank coal exported internationally as a steam coal; primarily for its blending properties with other coal to improve combustion. But for Alaskan low-rank coals to truly stand on their own merits, economical drying processes must be developed that produce a physically and chemically stable dried product. The technologies that have the most potential for increasing the use of Alaskan coals are those that can reduce the moisture content of these coals economically, and produce a fuel that is accepted in the international market place. Drying technologies will no doubt differ, depending on the end use of the fuel; be it dried lump coal, briquettes or pellets for pulverized coal or stoker applications, or concentrated coal-water fuels made from hot water dried LRCs. There are a number of developing processes that may work with Alaskan coals. Some drying processes, however, have been plagued by the production of excessive amounts of coal fines, Since the demand for Alaskan coal is currently limited to lump size coal, large quantities of fines are a definite liability. In this study, two high temperature drying/pyrolysis processes and one hydrothermal process were investigated. The high temperature drying/pyrolysis processes were conducted at (1) the Western Research Institute, (WRI) an affiliate of the University of Wyoming Research Corporation, Laramie, WY, and (2) Coal Technology Corporation (CTC) of Brisol, VA. Hydrothermal processing was conducted at MIRL, University of Alaska Fairbanks. A summary of these processes and the products they produced follows.The University of Alaska also provided matching funds for this project, which was a portion of a larger study that leveraged U.S. Department of Energy funds

An Exploratory Modeling of The Decision Process of New Product Selection by Supermarket Buyers

Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

Application to rotary wings of a simplified aerodynamic lifting surface theory for unsteady compressible flow

A general method of predicting airloads is applied to helicopter rotor blades on a full three-dimensional basis using the general theory developed for a rotor blade at the psi = pi/2 position where flutter is most likely to occur. Calculations of aerodynamic coefficients for use in flutter analysis are made for forward and hovering flight with low inflow. The results are compared with values given by two-dimensional strip theory for a rigid rotor hinged at its root. The comparisons indicate the inadequacies of strip theory for airload prediction. One important conclusion drawn from this study is that the curved wake has a substantial effect on the chordwise load distribution

The Strategic Role of Supermarket Buyer Intermediaries in New Product Selection: Implications for Systemwide Efficiency

Agribusiness,

Two Modes of Solid State Nucleation - Ferrites, Martensites and Isothermal Transformation Curves

When a crystalline solid such as iron is cooled across a structural transition, its final microstructure depends sensitively on the cooling rate. For instance, an adiabatic cooling across the transition results in an equilibrium `ferrite', while a rapid cooling gives rise to a metastable twinned `martensite'. There exists no theoretical framework to understand the dynamics and conditions under which both these microstructures obtain. Existing theories of martensite dynamics describe this transformation in terms of elastic strain, without any explanation for the occurence of the ferrite. Here we provide evidence for the crucial role played by non-elastic variables, {\it viz.}, dynamically generated interfacial defects. A molecular dynamics (MD) simulation of a model 2-dimensional (2d) solid-state transformation reveals two distinct modes of nucleation depending on the temperature of quench. At high temperatures, defects generated at the nucleation front relax quickly giving rise to an isotropically growing `ferrite'. At low temperatures, the defects relax extremely slowly, forcing a coordinated motion of atoms along specific directions. This results in a twinned critical nucleus which grows rapidly at speeds comparable to that of sound. Based on our MD results, we propose a solid-state nucleation theory involving the elastic strain and non-elastic defects, which successfully describes the transformation to both a ferrite and a martensite. Our work provides useful insights on how to formulate a general dynamics of solid state transformations.Comment: 3 pages, 4 B/W + 2 color figure

Public Preferences and Values for Rural Land Preservation in Florida

This study develops a method to evaluate the influence of local geography on respondents values for land conservation programs. The study employs a choice experiment to evaluate alternative conservation plans. Results indicate that residents local landscapes do matter to the estimated values for such conservation programs. Our results also provide information about the divergence of political and economic jurisdictions for land conservation programs in Florida.Land Economics/Use,