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Abstract The combination of biomass gasification with fuel cells, especially high temperature Solid Oxide Fuel Cells (SOFCs) promises sustainable and highly efficient (decentralized and modular) energy conversion systems. This review encompasses the components of biomass integrated gasification–SOFC technology including biomass characteristics, the thermochemical conversion in gasifiers and the factors affecting the gasification process, the cleaning technologies for raw producer gas and its conditioning and finally the integration of gasifier with SOFCs. The influence of impurities present in biomass producer gas such as particulates, tar, H 2 S, HCl and alkali compounds based on recent experimental studies and their tolerance limits towards SOFCs are presented. Even though analysis based on the probable tolerance limits of impurities towards SOFCs and a comprehensive overview of the cleaning technologies for producer gas impurities indicate that producer gas cleaning at various temperatures using current technologies to meet SOFC requirements is possible, more experimental studies are still needed to acquire the detailed information on the tolerance limits of impurities for SOFCs. The recent theoretical modeling and experimental studies of biomass integrated gasification–SOFC systems are also presented.

The Sulphurdale Geothermal Field is located in Beaver County Utah, within the boundaries of the Cove Fort--Sulphurdale Known Geothermal Resource Area (KGRA). During the past year, three wells drilled in Section 7, T-26-S, R-6-W, have produced dry steam from a fractured volcanic formation located at a depth of about 1100 feet. Two of these three wells are currently prepared to supply steam to a power plant, and one well has been plugged and abandoned. ThermaSource, Inc. was retained by Mother Earth Industries, the operator of the field, to conduct well tests and render an opinion as to the nature of the geothermal reserves and assess the commercial potential of these reserves. Because of the limited area that has been explored to date, there can be no assurance that the reserves estimate will prove accurate. Project economics are based on parameters believed to be accurate, but there is no assurance that such cash flow projections will be realized.

Summary Monitoring of microbial corrosion is always difficult because of the sessile nature of bacteria and the lack of meaningful correlation between routine bacteria counts and bacterial activity. This problem is further aggravated in a large oilfield water system because of size and sampling difficulties. This paper discusses some monitoring techniques currently used in the oil industry, their limitations, and possible areas for improvement. These improved techniques are in use or will be implemented in the Aramco systems. Introduction Microbial corrosion has caused some failures in seawater injection systems. Whether or not microbial corrosion represents a major corrosion mechanism in the oilfield water system is a controversial question. However, it has certainly become a major concern in recent years. There are two approaches in dealing with microbial corrosion problems in a large oilfield water system. One approach is to start treating the system with bactericide in conjunction with regular scraping when the system is commissioned. The other is to treat the system only when an impending microbial-related problem is clearly defined. in either case, monitoring of microbial corrosion is essential. The first approach is more or less a precautionary measure. The treatment and selection of bactericides is usually based on past experience and laboratory evaluation tests. While the treatment is being implemented, a reliable monitoring program could assess the effectiveness of the current program of microbial corrosion control. In the second case, monitoring of microbial corrosion is even more important. it would provide timely information toward implementation of a treatment program before the system could get out of control. The industry's awareness of microbial corrosion has been indicated by the number of papers published in recent years on this subject. These articles cover a wide spectrum of interest from fundamental corrosion mechanisms to case studies, detection methods, control measures, etc. Although it is not clear to what extent microorganisms are responsible for the observed field corrosion failures, the general consensus still favors early establishment of a routine microbial corrosion monitoring program. The best approach seems to he the establishment of solid baseline data for the system after which any significant future deviation can be interpreted as a sign of a potential problem. The following sections describe the current methods used for routine monitoring, specifically for Aramco's large oilfield water systems. The limitations of these methods, the difficulties encountered, and some suggested studies for modification and improvement are discussed also. Current Monitoring Methods The methods currently used by Aramco can be categorized as (l) cell counts in water, (2) metal surface examination, (3) scraping solids analysis, (4) water quality analysis, and (5) evaluation of current bactericide treatment. Cell Counts in Water. These are used to detect bacterial organisms and their concentrations. it is recognized that confirmation of free-flowing bacteria in the water does not automatically mean trouble. However, if bacteria counts demonstrate a definite increase across the system, or over a period of time, the odds are that bacteria are active and working on the metal somewhere in the system. Cell counts routinely monitored include sulfate-reducing bacteria (SRB), general aerobic bacteria (OAB), iron bacteria, and others. SRB are widely recognized to he primarily responsible for bacteria-induced corrosion in an anaerobic environment. Depending on the nature of the sample to be tested and the types of problems encountered (or expected) in the field, one or several different enumeration techniques are employed. For field work, the method generally used by Aramco is culturing of samples in liquid growth media specifically designed for detecting a certain group of organisms. These laboratory media are prepared using the appropriate field water as a base, with addition of general growth nutrients for the organisms. The use of field water to prepare the media provides a water composition similar to that in which the bacteria originated. The media are supplemented with other ingredients to create an environment conducive to growth of certain bacteria (e.g., certain reducing agents have to he added into the SRB media). The media then are dispensed into serum vials at exactly 9 mL [9 cm3] each and sealed with rubber stoppers and aluminum seals. JPT P. 1171

The cover of a disposal cell is an important element in the long-term stability of a reclaimed uranium tailings site. The cover is generally comprised of a radon barrier, filter, and surface erosion barrier. A study is conducted to investigate the drainage and erosion potential between the filter and radon barrier layer in response to surface water flows over a layer of riprap. A cover system is physically modeled in a hydraulics laboratory. The experimental program evaluated the interstitial velocity potential through four filters, the erosion and sediment transport potential from the radon barrier, and the filter drainage rate after passage of the surface runoff hydrograph. The results indicated that the use of traditional filter criteria to bed riprap is extremely conservative and restricts drainage. The grain size of the filter materials should be increased to enhance drainage when placed on flat (\IS\N ≤\N 5%) slopes. A relationship is presented for estimating the drainage velocity potential through a filter layer as a function of slope and gradation. A new filter criteria should be developed for overtopping flow conditions.

Abstract A new formulation for the evaporation, flashing, condensation processes taking place in the effects of thermal desalination systems which simulates the operation of both forward and parallel/cross configurations is coupled with an exergo-economic model based on the SPECO method. The thermo-economic model uses accurate properties for the seawater, brine, pure water and vapour and is solved with an equation solver which does not require the development of a specific solution algorithm as in most previous studies. This flexible model is used to analyze the influence of the number of effects N and the temperature difference ΔT e between effects on the technical and economic performance of multi-effect desalination systems with ejector vapour compression. In particular, it is shown that the performance calculated by an earlier black-box approach is not attainable by technically and economically realistic systems. It is also shown that for each feed configuration and a given number of effects there exists an optimum value of ΔT e which minimizes the cost of the produced potable water. This last result forms the basis of a procedure that combines black-box results with the optimum value of ΔT e and can be used to select the appropriate system for any specific application.

Biofuels have been identified as a mid-term GHG emission abatement solution for decarbonising the transport sector. This study examines the techno-economic analysis of biofuel production via biomass fast pyrolysis and subsequent bio-oil upgrading via zeolite cracking. The aim of this study is to compare the techno-economic feasibility of two conceptual catalyst regeneration configurations for the zeolite cracking process: (i) a two-stage regenerator operating sequentially in partial and complete combustion modes (P-2RG) and (ii) a single stage regenerator operating in complete combustion mode coupled with a catalyst cooler (P-1RGC). The designs were implemented in Aspen Plus® based on a hypothetical 72 t/day pine wood fast pyrolysis and zeolite cracking plant and compared in terms of energy efficiency and profitability. The energy efficiencies of P-2RG and P-1RGC were estimated at 54% and 52%, respectively with corresponding minimum fuel selling prices (MFSPs) of £7.48/GGE and £7.20/GGE. Sensitivity analysis revealed that the MFSPs of both designs are mainly sensitive to variations in fuel yield, operating cost and income tax. Furthermore, uncertainty analysis indicated that the likely range of the MFSPs of P-1RGC (£5.81/GGE  £11.63/GGE) at 95% probability was more economically favourable compared with P-2RG, along with a penalty of 2% reduction in energy efficiency. The results provide evidence to support the economic viability of biofuel production via zeolite cracking of pyrolysis-derived bio-oil.

Sustainability of agro-food supply chains has recently become the subject of greater interest from consumers, firms, governmental organizations and academia as the environment continues to deteriorate. One of the most critical factors influencing the sustainability of an agro-food supply chain is its network design. A particularly challenging aspect in this context is the broad range of influencing indicators associated with the Triple Bottom Line (TBL) of sustainability that need to be considered. However, many of these indicators could not be fully integrated or measured by single-step optimization problems. This paper presents a critical literature review of operational research methods for the design of sustainable supply chains. A novel two-stage hybrid solution methodology is proposed. In the first stage, a partner selection is performed using a hybrid multi criteria decision making based on Analytic Hierarchy Process (AHP) method and the Ordered Weighted Averaging (OWA) aggregation method. The result obtained in the first stage is used in the second stage to develop a multi-objective mathematical model to optimize the design of the supply chain network. This approach allows the simultaneous consideration of all three dimensions of sustainability including carbon footprint, water footprint, number of jobs created and the total cost of the supply chain design. The proposed approach generates a Pareto frontier to aid users in making decisions. Numerical experiments are completed utilizing data from an agro-food company to demonstrate the efficiency and effectiveness of the proposed solution methodology. The analyzes of the numerical results provide important organizational, practical and policy insights on (1) the impact of financial and environmental sustainability on supply chain network design (2) the tradeoff analysis between environmental emission, water footprint, societal implications and associated cost for making informed decision on supply chain investment.

The Houston-Dallas (I-45) corridor is the busiest route among 18 traffic corridors in Texas, USA. The expected population growth and the surge in passenger mobility may result in a significant impact on the regional environment. This study uses a life cycle framework to predict and evaluate the net changes of environmental impact associated with the potential development of a high-speed rail (HSR) System along the I-45 corridor through its life cycle. The environmental impact is estimated in terms of CO2 and greenhouse gas (GHG) emissions per vehicle/passenger-kilometers traveled (V/PKT) using life cycle assessment. The analyses are performed referring to the Ecoinvent 3.4 inventory database through the phases: material extraction and processing, infrastructure construction, vehicle manufacturing, system operation, and end of life. The environmental benefit is evaluated by comparing the potential development of the HSR system with those of the existing transportation systems. The vehicle component, especially operation and maintenance of vehicles, is the primary contributor to the total global warming potential with about 93% of the life cycle GHG emissions. For the infrastructure component, 56.76% of GHG emissions result from the material extraction and processing phase (23.75 kgCO2eq/VKT). Various life cycle emissions of HSR except PM are significantly lower than for passenger cars.