A modelling study of post-combustion capture plant process conditions to facilitate 95–99% CO2 capture levels from gas turbine flue gases

The principal purpose of this study is to examine the changes in process conditions that might be needed to achieve up to 99% capture levels in amine post-combustion capture (PCC) plants for combined cycle gas turbine (CCGT) flue gases. This information is of interest since, while 95% capture is adequate for current market and regulatory conditions, net zero fossil emissions (99% capture for a CCGT plant) will be required to deliver global climate mitigation targets and is increasingly a target for national climate policies. The conventionally-configured plant in the study is based on FEED studies carried out by Bechtel Corporation and uses MEA at 35% w/w. Performance modelling is undertaken using the Aspen Plus CCSI MEA Steady State Model. The results show that efficient operation at higher capture levels appears to be feasible with minimal adjustments to the plant configuration, provided that the absorber has a sufficient packing height and the stripper is capable of operation at pressures above 2 bar. The study primarily focuses on operation at low lean loadings (0.09–0.15 molCO2/molMEA) and correspondingly low L/G ratios (<1 by mass), the combination of which, in principle, can give a higher rich loading for a given capture level and packing height and consequently reduce energy consumption. However, for a given capture level, there is a minimum absorber packing height below which a near-optimal rich loading cannot be achieved for any lean loading and L/G ratio. For example, at a lean loading of 0.12 molCO2/molMEA, an absorber packing height of approximately 24 m is required for 99% capture with a minimal increase in specific energy requirements (3.77 GJ/tCO2 at 99% capture vs. 3.50 GJ/tCO2 at 95% capture). A stripper pressure of 2.4 bar is also found to be necessary to achieve this lean loading level without excessive energy requirements. The effect of varying lean loading at three constant rich loading levels is reported in detail, as are the effect of rich loading at constant lean loading and the effect of pressure on stripper performance and energy requirements. The study also examines the effects of cooling and intercooling at elevated capture levels. A simple analysis of break-even operating costs suggests that capture levels higher than the 95% envisaged in current United Kingdom guidance, to further reduce CO2 emissions costs for CCGT + PCC, might be attractive if carbon dioxide removal from air is the alternative

Availability analysis of post-combustion carbon capture systems: minimum work input

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Peer Assisted Learning to Support Student Role Transition in Occupational Therapy Education.

PAL may be defined as learning support enabling students to work co-operatively under the guidance of more experienced students. Second and third year students (PAL leaders) facilitate study sessions for groups of first or second years. PAL aims to support students to adjust to university life, to develop independent learning skills, and to acquire a clear view of course direction and subject matter through collaborative group discussion (Bournemouth University 2017). Transitioning into student roles can be complex and involves gaining a sense of relationships to others and of expected behaviours (Kielhofner 2008). Students are expected to dedicate their time to work activities to ensure academic success which may have a negative impact on occupational balance. Wilson and Wilcock (2005) suggest that first year occupational therapy students find it difficult to attain occupational balance due to environmental and personal factors and PAL sessions can assist with this transition. PAL has a positive impact not only for the student recipients but also for the PAL leaders in terms of confidence building, developing transferable skills and enhancing employability (Capstick et al 2004). From an educational perspective the PAL approach enhances deeper levels of engagement with the curriculum, supports stronger cohort identity and increases employability through the development of transferable skills. This poster will explore and reflect on the value of PAL in occupational therapy education for the students, PAL leaders and the educational organisation

Unique genetic and histological signatures of mouse pericardial adipose tissue

Obesity is a major risk factor for a plethora of metabolic disturbances including diabetes and cardiovascular disease. Accumulating evidence is showing that there is an adipose tissue depot-dependent relationship with obesity-induced metabolic dysfunction. While some adipose depots, such as subcutaneous fat, are generally metabolically innocuous, others such as visceral fat, are directly deleterious. A lesser known visceral adipose depot is the pericardial adipose tissue depot. We therefore set out to examine its transcriptional and morphological signature under chow and high-fat fed conditions, in comparison with other adipose depots, using a mouse model. Our results revealed that under chow conditions pericardial adipose tissue has uncoupling-protein 1 gene expression levels which are significantly higher than classical subcutaneous and visceral adipose depots. We also observed that under high-fat diet conditions, the pericardial adipose depot exhibits greatly upregulated transcript levels of inflammatory cytokines. Our results collectively indicate, for the first time, that the pericardial adipose tissue possesses a unique transcriptional and histological signature which has features of both a beige (brown fat-like) but also pro-inflammatory depot, such as visceral fat. This unique profile may be involved in metabolic dysfunction associated with obesity

Variability in stream discharge and temperature: a preliminary assessment of the implications for juvenile and spawning Atlantic salmon

This study focuses on understanding the temporal variability in hydrological and thermal conditions in a small mountain stream and its potential implication for two life stages of Atlantic salmon (<I>Salmo salar</I>) &ndash; stream resident juveniles and returning adult spawners. Stream discharge and temperature in the Girnock Burn, NE Scotland, were characterised over ten hydrological years (1994/1995&ndash;2003/2004). Attention was focussed on assessing variations during particular ecologically 'sensitive' time periods when selected life-stages of salmon behaviour may be especially influenced by hydrological and thermal conditions. <P style='line-height: 20px;'> Empirical discharge data were used to derive hydraulic parameters to predict the Critical Displacement Velocity (CDV) of juvenile salmon. This is the velocity above which fish may no longer be able to hold station in the water column and thus can be used as an index of time periods where feeding behaviour might be constrained. In the Girnock Burn, strong inter- and intra-annual variability in hydrological and thermal conditions may have important implications for feeding opportunities for juvenile fish; both during important growth periods in late winter and early spring, and the emergence of fry in the late spring. Time periods when foraging behaviour of juvenile salmon may be constrained by hydraulic conditions were assessed as the percentage time when CDV for 0+ and 1+ fish were exceeded by mean daily stream velocities. Clear seasonal patterns of CDV were apparent, with higher summer values driven by higher stream temperatures and fish length. Inter-annual variability in the time when mean stream velocity exceeded CDV for 0+ fish ranged between 29.3% (1997/1998) and 44.7% (2000/2001). For 1+ fish mean stream velocity exceeded CDV between 14.5% (1997/1998) and 30.7% (2000/2001) of the time. <P style='line-height: 20px;'> The movement of adult spawners into the Girnock Burn in preparation for autumn spawning (late October to mid-November) exhibited a complex relationship with hydrological variability with marked inter-annual contrasts. In years when discharge in the period prior to spawning was low, fish movement was increasingly triggered by suboptimal flow increases as spawning time approached. In contrast, wet years with numerous events allowed a much more even distribution of fish entry. Elucidating links between discharge/temperature variability and foraging opportunities and upriver migration of adult Atlantic salmon have the potential to contribute to the improvement of conservation strategies in both regulated and unregulated rivers

OxyCAP UK: Oxyfuel Combustion - academic Programme for the UK

The OxyCAP-UK (Oxyfuel Combustion - Academic Programme for the UK) programme was a £2 M collaboration involving researchers from seven UK universities, supported by E.On and the Engineering and Physical Sciences Research Council. The programme, which ran from November 2009 to July 2014, has successfully completed a broad range of activities related to development of oxyfuel power plants. This paper provides an overview of key findings arising from the programme. It covers development of UK research pilot test facilities for oxyfuel applications; 2-D and 3-D flame imaging systems for monitoring, analysis and diagnostics; fuel characterisation of biomass and coal for oxyfuel combustion applications; ash transformation/deposition in oxyfuel combustion systems; materials and corrosion in oxyfuel combustion systems; and development of advanced simulation based on CFD modelling