A review: Interlayer joining of nickel base alloys

This article provides a comprehensive review of the improvements and results in interlayer bonding of nickel and its alloys to other metal alloys. The development of the interlayer bonding process in joining nickel-based alloys is of high interest to the aerospace and power generation industries, with the idea of on-site repair of turbine components of focus. History of the diffusion bonding process has been summarized, and bonding parameters and methods for various alloy combinations have been outlined. The relationship between hardness and strength, to the intermetallic compounds and porosity present in the bond region has been illustrated. The literature shows the methods for manipulating the volume of these compounds, and subsequent strength. The paper also shows the microstructural changes that occur during interlayer bonding and how these may be manipulated by changing bonding parameters and interlayer composition. Recent and influential papers have been summarized, with the key findings outlined, the type of interlayer and alloy/s being joined have been headlined for ease of navigation, when available, bond strengths and mechanical property values have been highlighted to illustrate bond soundness. This review does not concern traditional fusion welding methods

Thermoelectric generator (TEG) technologies and applications

2021 The Author(s). Nowadays humans are facing difficult issues, such as increasing power costs, environmental pollution and global warming. In order to reduce their consequences, scientists are concentrating on improving power generators focused on energy harvesting. Thermoelectric generators (TEGs) have demonstrated their capacity to transform thermal energy directly into electric power through the Seebeck effect. Due to the unique advantages they present, thermoelectric systems have emerged during the last decade as a promising alternative among other technologies for green power production. In this regard, thermoelectric device output prediction is important both for determining the future use of this new technology and for specifying the key design parameters of thermoelectric generators and systems. Moreover, TEGs are environmentally safe, work quietly as they do not include mechanical mechanisms or rotating elements and can be manufactured on a broad variety of substrates such as silicon, polymers and ceramics. In addition, TEGs are position-independent, have a long working life and are ideal for bulk and compact applications. Furthermore, Thermoelectric generators have been found as a viable solution for direct generation of electricity from waste heat in industrial processes. This paper presents in-depth analysis of TEGs, beginning with a comprehensive overview of their working principles such as the Seebeck effect, the Peltier effect, the Thomson effect and Joule heating with their applications, materials used, Figure of Merit, improvement techniques including different thermoelectric material arrangements and technologies used and substrate types. Moreover, performance simulation examples such as COMSOL Multiphysics and ANSYS-Computational Fluid Dynamics are investigated

Chemical Flooding in Naturally Fractured Reservoirs: Fundamental Aspects and Field-Scale Practices

Appropriate methods should be employed to enhance the oil recovery from the Naturally Fractured Reservoirs (NFRs). One of the candidates for enhancing the oil recovery from these reservoirs is the surfactant-based chemical flooding. This paper highlights the technical achievements and challenges of the chemical flooding in the NFRs. The classification, production characteristics, recovery mechanisms of the NFRs and significant findings of the chemical flooding in these reservoirs are reviewed and analyzed. It is expected that this paper will serve as a helpful reference tool for the engineers interested in chemical flooding in the NFRs

Chemical Flooding in Naturally Fractured Reservoirs: Fundamental Aspects and Field-Scale Practices

Appropriate methods should be employed to enhance the oil recovery from the Naturally Fractured Reservoirs (NFRs). One of the candidates for enhancing the oil recovery from these reservoirs is the surfactant-based chemical flooding. This paper highlights the technical achievements and challenges of the chemical flooding in the NFRs. The classification, production characteristics, recovery mechanisms of the NFRs and significant findings of the chemical flooding in these reservoirs are reviewed and analyzed. It is expected that this paper will serve as a helpful reference tool for the engineers interested in chemical flooding in the NFRs. Des méthodes appropriées devraient être utilisées pour augmenter la récupération d’huile des réservoirs naturellement fracturés (RNFs). Un des candidats pour augmenter cette récupération d’huile de ces réservoirs est l’injection d’eau contenant des agents chimiques. Cet article met en lumière les résultats techniques et les défis de cette technique. La classification, les caractéristiques de production, les mécanismes de rétablissement du RNFs et les résultats significatifs de l’injection d’eau contenant des agents chimiques dans ces réservoirs sont passés en revue et analysés. Ce papier vise à être un outil de référence utile aux ingénieurs intéressés par l’injection d’eau contenant des agents chimiques dans les RNFs

Enhanced Cyclic Solvent Process (ECSP) for Thin Heavy Oil Reservoirs

Vapour extraction (VAPEX) process has a low production rate and is not suitable for thin reservoirs due to lack of efficient gravity drainage. Cyclic solvent process (CSP) has been proposed to improve the production rate of solvent processes. A major problem of CSP is that during production, the reservoir pressure has to be greatly reduced in order for the solvent gas drive to occur during which oil regains its high viscosity because a significant amount of solvent gas evolves out of oil. Also, at low-to-intermediate pressures, the methane solubility in the oil is not high. Additionally, continuous free gas saturation during early production results in high gas mobility and the pressure, and thus, the drive energy can be quickly depleted by gas production. To overcome the problems of VAPEX and CSP, a new process for in-situ heavy-oil recovery- Enhanced CSP (ECSP) is developed in this study. ECSP effectively utilizes the viscosity reduction and solvent gas drive mechanisms during the production. ECSP experiments are performed to analyze the mechanisms and develop the optimal combination of two solvent slugs and injection/production strategy to optimize the injection process for improving the CSP in thin heavy-oil reservoirs. It is also shown that other ways of improving CSP is either to repressurize the system using water injection, i.e., conducting cyclic gas-alternating-water injection, or to conduct surfactant-enhanced CSP. Various aspects of ECSP are investigated under different injection sequences of two gas slugs. The impact of foamy solution gas drive mechanism on ECSP is also investigated. Then, phase behavior simulation is carried out for different heavy oil-solvent systems to predict the phase behavior of gas/gas mixtures with heavy-oil. Using a validated simulation model, the impacts of various parameters on ECSP are examined to analyze the mechanisms and illustrate the possible optimum ECSP designs. This study has produced experimental results for CSP, ECSP, cyclic gas-alternating-water injection, surfactant-enhanced CSP, extended waterflood, PVT data and phase behavior simulation, detailed cyclic solvent injection technique, PVT and simulation models for evaluation and optimization of ECSP, history-match and parametric study of ECSP, and guideline of ECSP for thin heavy-oil reservoirs

The Performance Evaluation of Viscous-Modified Surfactant Waterflooding in Heavy Oil Reservoirs at Varying Salinity of Injected Polymer-Contained Surfactant Solution

ABSTRACT: This study examines the effects of change in the concentrations of monovalent and divalent ions in the polymer-contained surfactant solution on the macroscopic behavior of viscous-modified surfactant waterflooding in heavy oil reservoirs. Salts that are used in this set of floods were sodium chloride, magnesium chloride, and calcium chloride. The results indicate that four different ranges of salinity (in terms of CaCl 2 concentration) exist. Each of these ranges renders a unique behavior regarding the ultimate oil recovery trends. There exists a range of salinity in which the ultimate oil recovery does not change with the salinity increase. The second salinity range is beyond the salt tolerance (i.e., first salinity range) of the polymer-contained surfactant solution, which results in a decrease in the ultimate oil recovery. In the third range of salinity, ultimate oil recovery is enhanced due to the plugging of high-permeable pores. In the fourth salinity range, precipitation increases as the salinity increases and more pore throats (even some pores with intermediate permeability) are plugged and, thus, the ultimate oil recovery decreases