The sedimentology of the Lower Fars Formation (Miocene) of Northern Iraq

PhD ThesisThis thesis incorporates a study of the petrology and sedimentology of rocks of the Gachsaran Formation (formerly lower Fars) (Miocene) in northern Iraq. Field sttdy led to the recognition of three basic lithofacies: mudrock, limestone and gypsum-anhydrite, which are arranged into cycles. The lithofacies are interpreted as the deposits of subtidal, intertidal and supratidal environments by comparison with Recent sediments, particularly those developing along the Trucial Coast, Arabian Gulf. Petrological studies show that the gypsum is secondary after anhydrite. Several types of sulphate textures are distinguished, each of which is described and its origin interpreted. The dominant nodular nature of the sulphates and their occurrence in repeated mudrock, limestone, sulphate cycles are consistent with a supratidal (sabkha) origin. Geochemical data were also used to aid in the interpretation of the depositional environment and diagenesis of the sulphates. Detailed petrographic examination of the limestones has led to the distinction of twelve carbonate-lithofacies. The most common types are peloidal and bioclastic limestones as well as oolitic and oncolitic varieties. Stromatolites and cryptalgal laminites are also present and their significance is discussed. In general the limestones are interpreted as deposited in shallow suibtidal to intertidal situations. Diagenetic events in the limestones include early and late cementation, dissolution and some dolomitization. Early diagenetic cementation appears to have been widespread. Two types of dolomite are recognised: an early non-rhombohedral variety resembling micrite, and a much coarser, later diagenetic dolomite. Geochemical data indicate diagenesis in both open and closed systems. The limestones possess average Fe and Mn contents, but Mg is relatively low compared with published limestone analyses. The very high content of Sr in some of the carbonate rocks is taken to indicate that aragonite has been an important early mineral in these rocks. The Na content, a reflection of salinity, indicates hypersalinity, especially for the dolostones. With regard to the mudrocks, illite is the dominant clay mineral with montmorillonite, mixed-layer clays and kaolinite less common. On the basis of colour, mineralogy and type of Foraminifera present, two types of mudrock are recognised: a green variety with benthic Foraminifera, other fossils and higher kaolinite, interpreted as deposited in hypersaline lagoons, and a red variety with planktonic Foraminifera, and a lower kaolinite content, interpreted as of relatively deep water origin. Cycles of mudrock - limestone- gypsum, limestone - gypsum and mudrock - gypsum are interpreted as sabkha cycles produced through the progradation of sabkhas over intertidal and aubtidal sediments. A consideration of the tectonic context of the Mesopotamian Basin suggests that vertical tectonic movements may well have been an important factor in Gachsaran deposition and the development of the cyclicity, as well as eustatic sea-level changes through variations in the extent of polar glaciation and plate tectonic movements

An experimental feasibility study on fast pyrolysis of MSW-derived trommel fines for energy recovery and waste management

Trommel fines are solid wastes with particle sizes of 30 wt.%) and along with the volatile matter and higher heating values (HHV), varied in relation to particle sizes. By careful pre-treatment process design, the size fraction 0.5 mm – 2 mm, which was suitable for fast pyrolysis, had an experimental energy content of 13.8 MJ kg -1. The energy contents of the AW and AWS feedstocks increased with a reduction in ash contents after the respective washing procedures. A 300 g h-1 bubbling fluidised bed fast pyrolysis rig was used to investigate the effect of temperature and moisture content on product yields and process conversion efficiency of dry physically pre-treated trommel fines (PT) to determine their optimum processing conditions. Investigations were also undertaken to study the effect of feedstock pre-treatment method; dry (PT) and wet (AW and AWS) on both the pyrolysis products and process conversion efficiency. Using PT feedstock, the highest organic liquid yield and highest conversion efficiency was obtained between 500 °C and 550 ºC with <3 wt% feedstock moisture content. The organic liquid yield and the process conversion efficiencies increased with AW and AWS feedstocks, with AW feedstock giving the best results. The HHV of primary condensate from all feedstocks was greater than 30 MJ kg-1 and the washing procedure was found to reduce the nitrogen contents of the liquid products especially in the secondary condensate liquids.The fast pyrolysis results were used to determine the economic feasibility of the fast pyrolysis technology at PT optimum processing conditions for energy recovery and management of trommel fines at different processing capacities. The PT fast pyrolysis was found to be economically feasible from 2000 kg h-1 processing capacity, with a capital investment payback period of 8.6 years at 20% interest rate. The net present value (NPV) increased with the AW and AWS feedstocks and further analysis showed that processing these feedstocks could still be economically feasible at capacities of approximately 1000 kg h-1. 3 Overall, the results of this study suggest that the laboratory-scale fast pyrolysis rig used in this study and the developed economic model can form the basis for future research and process development for treatment of MSW

Proceedings of the Conference on Coal Use for California

The papers, statements, and panel session transcriptions that resulted from the conference are presented. The conference brought together approximately 400 specialists, students, interest groups and general public for the examination of technological, institutional, and social issues surrounding coal use for California and the identification of attendant constraints, impediments, advantages, and target opportunities. The expertise of the participants cover a wide range of subject matter that includes systems examination of coal opportunities, energy demand forecasting, environmental aspects of coal use, coal supply and transport, viewpoint of neighboring states, air pollution control, direct firing, coal gasification and liquefaction technologies, economics of coal use, and the regulatory system