Liquefaction experimental studies

Experimental Studies of the Dependence of Liquefaction Behavior of U.S. Coals on Coal Characteristics... 

Two types of biomass-derived oils have been studied at PNL. The first type of oil is produced by high pressure liquefaction at relatively long residence times. Oils identified as TR7 and TR12 in Table I were produced by this type of process at the Albany, Oregon Biomass Liquefaction Experimental Facility. These highly viscous oils consist primarily of substituted phenols and naphthols (1-2). The other type of oil is produced by low-pressure, flash pyrolysis at somewhat higher temperature and very short residence times. 

This article presents results from an experimental study of pre- and post-liquefaction characteristics of non-plastic sand-silt mixes at silt contents from 0% to 100% by weight, and three natural non-plastic silts. Undrained cyclic triaxial tests followed by dissipation of cyclic-induced pore pressures were carried out in order... 

A comprehensive laboratory experimental study on pore pressure generation, post-liquefaction... 

Dettleff,G., Thompson,P.A., Meier,E.A. and Speckmann,H. An experimental study of liquefaction shock wave, J.Fluid.Mech. Vol.95 (1979), 279-304... 

The experimental study of liquefaction shocks in large-heat capacity fluids has revealed the shock front instability (P.A.Thompson, G.C. Carofano, Y.G. Kim, 1986). With growth of the Mach number the following types of irregular shock front behaviour were observed appearance of disturbances in the vicinity of the shock tube symmetry axis, regular waves at the shock front, chaotic behaviour and fracture of the shock front. 

The liquefaction of coals was studied in a 500 ml magnetically-stirred stainless steel antoclave. Two different reaction conditions were used in this study, hut the experimental procedures were almost the same in both conditions. 

The analytical data for coal samples used by other researchers and their experimental results are shown in Tables 6 and 7. A rough comparison of the liquefaction conditions used in this study to explore the parameter representing coal characteristics is shown in Table 8. 

The strategies used in studies of high temperature reactions of metals have been brought to bear on some of the problems associated with the direct liquefaction of coaL Many coals contain sulfur, combined in both organic and inorganic forms, in excess of amounts allowable under current combustion standards. In some coals much of the sulfur is in the form of pyrite, Fe 2> which may, paradoxically, serve as a catalyst or the precursor of a catalyst for the liquefaction process. The information available for the Fe-S-O-H system has been assembled in an attempt to provide a framework for interpreting experimental results, and to facilitate the planning of further experim ents. 

In recent years, it has been realized that mineral matter plays an important role in coal liquefaction (9-11), similar to the role of the added catalyst in the Bergius process. Several experimental techniques have been used to study the effects of minerals on coal liquefaction and to identify the specific catalytic phase (12). Most studies (12-14) strongly imply that the iron sulfides are the roost active species, and the other minerals appear to have little effect on enhancement of liquid yield or quality. 

Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy has been proven to be an excellent means of characterizing coals and related materials. This report is devoted to the evaluation of the technique as a method for situ monitoring of the chemical structural changes wrought in reactions of coal with fluid phases. This technique does not require a supporting medium (matrix) which can contain chemical artifacts which inherently serve as a barrier for access to the solid coal. The rapid response of the Fourier transform infrared technique is further beneficial for kinetic studies related to combustion, liquefaction, gasification, pyrolyses, etc. Experimental equipment and techniques are described for studies over wide ranges of pressure (10 5 Pa to ca 1.5 x 10 kPa) and temperature (298 K to 800 K). 

Inherent coal minerals are readily available and inexpensive catalysts for liquefaction, hydrogenation/hydrocracking and heteroatom removal reactions. In recent years, experimental work has been carried out to determine (a) liquefaction behavior of various coals with different mineral matter contents, (b) liquefaction behavior by adding various mineral matter in or to a particular coal or by reducing the mineral matter contents of a coal by some physical means and (c) liquefaction behavior in the presence of a variety of externally added catalysts. Some of these studies are briefly described below. 

The primary purpose of this paper is to describe the kinetics of coal liquefaction derived from a pilot-scale unit. The specific coal studied was Big Horn subbituminous coal. The experimental data were obtained in a pilot-scale Gulf patented (13) reactor. The data illustrate the effects of reactor space time and temperature on the product distribution. Since the reactor behaves as a bubble column, the intrinsic kinetics of the liquefaction process can be extracted by means of a kinematic model of the reactor. The experimental data were found to be... 

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