A systematic investigation of the performance of copper-, cobalt-, iron-, manganese-, and nickel-based oxygen carriers for chemical looping combustion technology through simulation studies

The Integrated Gasification Combined Cycle coupled with chemical looping combustion (IGCC-CLC) is one of the most promising technologies that allow generation of cleaner energy from coal by capturing carbon dioxide (CO2). It is essential to compare and evaluate the performances of various oxygen carriers (OC), used in the CLC system; these are crucial for the success of IGCC-CLC technology. Research on OCs has hitherto been restricted to small laboratory and pilot scale experiments. It is therefore necessary to examine the performance of OCs in large-scale systems with more extensive analysis. This study compares the performance of five different OCs – copper, cobalt, iron, manganese and nickel oxides – for large-scale (350–400 MW) IGCC-CLC processes through simulation studies. Further, the effect of three different process configurations: (i) water-cooling, (ii) air-cooling and (iii) air-cooling along with air separation unit (ASU) integration of the CLC air reactor, on the power output of IGCC-CLC processes – are also investigated. The simulation results suggest that iron-based OCs, with 34.3% net electrical efficiency and ~100% CO2 capture rate lead to the most efficient process among all the five studied OCs. A net electrical efficiency penalty of 7.1–8.1% points leads to the IGCC-CLC process being more efficient than amine based post-combustion capture technology and equally efficient to the solvent based pre-combustion capture technology. The net electrical efficiency of the IGCC-CLC process increased by 0.6–2.1% with the use of air-cooling and ASU integration, compared with the water- and air-cooling cases. This work successfully demonstrates a correlation between the reaction enthalpies of different OCs and power output, which suggests that the OCs with higher values of reaction enthalpy for oxidation (ΔHr, oxidation) with air-cooling are more valuable for the IGCC-CLC

Streamlining Digital Modeling and Building Information Modelling (BIM) Uses for the Oil and Gas Projects

The oil and gas industry is a technology-driven industry. Over the last two decades, it has heavily made use of digital modeling and associated technologies (DMAT) to enhance its commercial capability. Meanwhile, the Building Information Modelling (BIM) has grown at an exponential rate in the built environment sector. It is not only a digital representation of physical and functional characteristics of a facility, but it has also made an impact on the management processes of building project lifecycle. It is apparent that there are many similarities between BIM and DMAT usability in the aspect of physical modeling and functionality. The aim of this study is to streamline the usage of both DMAT and BIM whilst discovering valuable practices for performance improvement in the oil and gas projects. To achieve this, 28 BIM guidelines, 83 DMAT academic publications and 101 DMAT vendor case studies were selected for review. The findings uncover (a) 38 BIM uses; (b) 32 DMAT uses and; (c) 36 both DMAT and BIM uses. The synergy between DMAT and BIM uses would render insightful references into managing efficient oil and gas’s projects. It also helps project stakeholders to recognise future investment or potential development areas of BIM and DMAT uses in their projects

Impacts of geological store uncertainties on the design and operation of flexible CCS offshore pipeline infrastructure

Planning for Carbon Capture and Storage (CCS) infrastructure needs to address the impact of store uncertainties and store flow variability on infrastructure costs and availability. Key geological storage properties (pressure, temperature, depth and permeability) can affect injectivity and lead to variations in CO2 flow, which feed back into the pipeline transportation system. In previous storage models, the interface between the reservoir performance and the transportation infrastructure is unclear and the models are unable to provide details for flow and pressure management within a transportation network in response to changes in the operation of storage sites. Variation in storage demand due to daily and seasonal variations of fossil fuels uses and by extension CO2 flow is also likely to influence transportation infrastructure availability and the capacity to deliver. This work examines, at the level of infrastructure planning, the impact of store properties on CCS transportation and injection infrastructure in the context of flow variability. Different off-shore transportation scenarios, relevant to CCS in the UK, are evaluated using rigorous process modelling tools. Considering flow variations of ±50% of a given baseline flow, the results of the analysis indicate that enabling store flexibility is simpler in reservoirs with an initial pressure above 20 MPa. Wellhead conditions are influenced significantly by subsurface conditions. The operational envelope of the storage site is limited by the proximity of wellhead conditions to the CO2 phase equilibrium line and the maximum fluid velocities inside the well. Given reductions in reservoir permeability, the requirements for pressure delivery are strongly dependent on the reservoir temperature. This work provides detailed insight on the expected impacts of store properties on transportation infrastructure design and operation

The impact on patient trust of legalising physician aid in dying

Objective: Little empirical evidence exists to support either side of the ongoing debate over whether legalising physician aid in dying would undermine patient trust. Design: A random national sample of 1117 US adults were asked about their level of agreement with a statement that they would trust their doctor less if "euthanasia were legal [and] doctors were allowed to help patients die". Results: There was disagreement by 58% of the participants, and agreement by only 20% that legalising euthanasia would cause them to trust their personal physician less. The remainder were neutral. These attitudes were the same in men and women, but older people and black people had more agreement that euthanasia would lower trust. However, overall, only 27% of elderly people (age 65+) and 32% of black people thought that physician aid in dying would lower trust. These views differed with physical and mental health, and also with education and income, with those having more of these attributes tending to view physician aid in dying somewhat more favourably. Again, however, overall views in most of these subgroups were positive. Views about the effect of physician aid in dying on trust were significantly correlated with participants' underlying trust in their physicians and their satisfaction with care. In a multivariate regression model, trust, satisfaction, age, and white/black race remained independently significant. Conclusion: Despite the widespread concern that legalising physician aid in dying would seriously threaten or undermine trust in physicians, the weight of the evidence in the USA is to the contrary, although views vary significantly