Shale chemical characterization

In this chapter we will describe some of our initial evaluation work on Paraho shale oil. This initial evaluation was not performed in depth rather, this first step consisted of chemical characterizations and high-spot, bench-scale processing of oil shale and several other syncrudes for direct comparisons of chemical feedstocks potential. Conventional analytical and petroleum processing techniques were used in the expectation that these would provide reference data on which to base specifically adapted techniques for evaluations of individual syncrudes. The results represent only our first attempts and except for occasional comparisons, are only for Paraho shale oil. 

Two main approaches have been used toward the chemical characterization of kerogens of Brazilian oil shales ... 

The chemical compositions of oil shales and oil shale kerogen have been studied extensively (20). However, little work has been done to integrate chemical composition data in order to aid in the selection of suitable extracting processes. In this study, five analysis methods were used to chemically characterize the samples. These methods included Rock-Eval analysis, Fischer analysis, Xi C NMR, Ultimate analysis, and X-ray diffraction mineral analysis. 

Relation Between Fuel Properties and Chemical Composition. Chemical Characterization of U.S. Navy Shale-II Fuels... 

The Navy has completed two crude production/refining exercises with shale. The first of these, a 10,000 barrel operation (Shale-I), is described in two reports (1 2). The second, a 73,000 barrel operation (Shale-II), was completed in 1979 at the Toledo refinery of The Standard Oil Company (Ohio) (3). This paper describes the chemical characterization of the JP-5 and DFM from the Shale-II project. 

The U.S. Navy has been involved for some time in the development of Navy fuels from alternative sources (shale oil, tar sands and coal). As a part of this effort, the Naval Research Laboratory and the Naval Air Propulsion Center have been studying the characteristics of these fuels (.1, 2). NKL and NAPC are currently participating in a program to characterize the products from the Shale-II refining process conducted by the Standard Oil Company of Ohio (SOHIO) at their refinery in Toledo, Ohio. This paper is concerned with a part of this program and is a surrmary of the work on the physical and related properties of three military type fuels derived from shale JP-5 and JP-8 jet turbine fuels, and diesel fuel marine (DEM) (3, 5). Another paper of this symposium (6) will discuss the chemical characterization of the fuels. 

Solash, J. Hazlett, R. N. Burnett, J. C. Beal, E. and Hall, J. M. "Relation Between Fuel Properties and Chemical Composition. II. Chemical Characterization of U.S. Navy Shale-II Fuels," in this book. 

As the intermediates and products were not physically or chemically characterized, their precise definitions are omitted to avoid introducing arbitrary terms. The reaction scheme reveals a similarity between intermediate and the bitumen in oil shale (B). Intermediate 2 could be associated with bitumen generated by the thermal treatment of oil shale, which pyrolyses at lower temperatures in the same way as the bitumen originally present in oil shale. This is indicated by the almost identical activation energies obtained by TGA analysis. 

Materials from a solvent-refined coal pilot plant and two simulated in situ oil shale retort facilities have been characterized for trace inorganic and organic compounds. The techniques used allowed the determination of some 30 elements, the chemical and physical forms of arsenic and mercury, and a large number of organic compounds. Satisfactory balances were obtained for most trace elements except mercury in effluents from the solvent-refined coal plant and one of the oil shale retorts. Approximately 60 organic compounds were determined quantitatively in process streams from the solvent-refined coal plant, and 20 organic compounds were determined in the crude shale oil from an oil shale retort pilot plant. 

Over the past few years, established analytical chemical methodology for crude oil and refined petroleum derivatives has been extended to the rapidly expanding field of coal liquefaction products and has assisted in the substantive reappraisal of such potential liquid fuel sources as oil shale, tar sands, and similar bitumenous deposits. While many of the analytical problems of separation, identification, and characterization are common to all of these fields, each area exhibits distinct requirements calling for specific development of appropriate methodology. Indeed, the added chemical complexity of the nonpetroleum-based liquid fuel sources presents many novel challenges to the chemical investigator. 

The chemical behavior of various minor and trace elements is relatively well characterized for particular redox conditions, and there has been significant effort directed at the development of geochemical proxies for paleo-oxygenation in black shale sequences (see reviews in Calvert and Pedersen, 1993 Arthur and Sageman, 1994 Jones and Manning, 1994 Wignall, 1994 Schieber et u/., 1998a,b). Elements... 

Chemical differences are indeed evident between average shale composition. Post-Archaean sediments are characterized by higher levels of incompatible elements, higher K/Na, Th/Sc, Th/La, Th, and U than Archaean sediments (Fig. 4.15). A comparison of rare Earth... 

Petroleum reserves are limited and supplies are becoming expensive and unstable. Extensive efforts are underway in the United States and abroad to find alternative sources for fuel and chemicals by employing coal, oil shale, tar sands, and biomass. But complicated processing of these raw materials is required to deliver environmentally acceptable products at a competitive price. It is, therefore, increasingly important to obtain better characterization of these raw materials and better understanding of their transformation in a process. 

More recently, Kelemen et al. [154] discussed the pros and cons of XPS, XANES, and N NMR for characterizing and identifying the chemical forms of nitrogen in complex carbonaceous systems. They used both XPS and N NMR quantitatively to study kerogen obtained by demineralization of a Green River oil shale and of a peat sample, as well as chars obtained by pyrolysis and isoquinoline- and quinoline-derived chars. The inherent advantage of using a combination of these methods has thus been demonstrated. 

Due to low water contents, high specific surface areas and pore structures (see the previous section), the water-rock interactions within the Tournemire shales must be characterized by strong short range (nanometre-scale) water (or solute) molecules-mineral interactions. Therefore, the physico-chemical characteristics of the water and its solutes will be different from that of free water which is conventionally considered to take part in water-rock interactions (Horseman et al. 1996). The difference arises from factors such as the very low mobility of water in thin films, the high suction potentials developed owing to water-mineral surface electrostatic interactions and the membrane filtration of anions. The 9% porosity given above must be considered as a maximum value since waters bound chemically to mineral surfaces are included in the estimates in reality free waters are of most importance to the present study. 

Further evidence for the ability of chemical processes within the shale to retard important radionuclides, is provided by the distribution of Ce and Ba. These elements are chemical analogues for the radiologically important elements Th and Ra respectively, which are important constituents of many radioactive wastes. The elevated levels of Ce and Ba in the shale matrix, compared to the levels in the calcite veins (Table 2) may be evidence that these elements were relatively immobile during the formation of the calcite veins. An implication is that Th and Ra would also have been relatively immobile under these conditions (undisturbed far-field conditions). Such investigations require, however, better characterization of the mineral sinks for Ba, Ce and other trace elements, and determination of the calcite crystallization mechanisms. 

Laboratory scale experiments performed under well-controlled conditions represent a complementary approach towards the characterization of the chemical containment of radionuclides in the undisturbed and fractured shales. Sorption isotherms of Cs for the shale matrix and for calcite are provided in Fig. 6. Batch experiments were carried out in gloveboxes under N2 atmosphere and with synthetic fracture water which approximate in situ and far-field conditions. The liquid/solid ratio was 5mlg . The results show the weaker retention of Cs by calcite fillings than by the shale matrix. Interstrati-fied I/S have strong affinities for many radionuclides (Milton Brown 1986), whereas calcite is known to have small laboratory values for... 

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