Optimising the nanoporous architecture of solid acid and base catalysts for biodiesel synthesis

Dwindling oil reserves and growing concerns over CO2 emissions and associated climate change are driving the utilisation of renewable feedstocks as alternative, sustainable fuel sources. While rising oil prices are improving the commercial feasibility of biodiesel production, many current processes still employ homogeneous acid and/or base catalysts to transform plant or algae oil into the fatty acid methyl ester (FAME) components of biodiesel. Fuel purification requires energy intensive aqueous quench and neutralization steps, thus the rational design of new high activity catalysts is required to deliver biodiesel as a major player in the 21st century sustainable energy portfolio. Advances in the development of heterogeneous catalysts for biodiesel synthesis require catalysts with pore architectures designed to improve the accessibility of bulky viscous reactants typical of plant oils. Here we discuss how improvements to active site accessibility and catalyst activity in transesterification or esterification reactions can be achieved either by designing hierarchical pore networks or by pore expansion and use of interconnected pore architectures.

Message passing for distributed optimisation of power allocation with renewable resources

The increase in renewable energy generators introduced into the electricity grid is putting pressure on its stability and management as predictions of renewable energy sources cannot be accurate or fully controlled. This, with the additional pressure of fluctuations in demand, presents a problem more complex than the current methods of controlling electricity distribution were designed for. A global approximate and distributed optimisation method for power allocation that accommodates uncertainties and volatility is suggested and analysed. It is based on a probabilistic method known as message passing [1], which has deep links to statistical physics methodology. This principled method of optimisation is based on local calculations and inherently accommodates uncertainties; it is of modest computational complexity and provides good approximate solutions.We consider uncertainty and fluctuations drawn from a Gaussian distribution and incorporate them into the message-passing algorithm. We see the effect that increasing uncertainty has on the transmission cost and how the placement of volatile nodes within a grid, such as renewable generators or consumers, effects it.

The discretionary role of the line manager in inspiring work engagement and innovative behaviour:a study of social exchange and job resources in the public sector

This thesis is about the discretionary role of the line manager in inspiring the work engagement of staff and their resulting innovative behaviour examined through the lens of Social Exchange Theory (Blau, 1964) and the Job Demands-Resources theory (Bakker, Demerouti, Nachreiner & Schaufeli, 2001). The study is focused on a large British Public Sector organisation undergoing a major organisational shift in the way in which they operate as part of the public sector. It is often claimed that people do not leave organisations; they leave line managers (Kozlowski & Doherty, 1989). Regardless of the knowledge in the literature concerning the importance of the line manager in organisations (Purcell, 2003), the engagement literature in particular is lacking in the consideration of such a fundamental figure in organisational life. Further, the understanding of the black box of managerial discretion and its relationship to employee and organisation related outcomes would benefit from greater exploration (Purcell, 2003; Gerhart, 2005; Scott, et al, 2009). The purpose of this research is to address these gaps with relation to the innovative behaviour of employees in the public sector – an area that is not typically associated with the public sector (Bhatta, 2003; McGuire, Stoner & Mylona, 2008; Hughes, Moore & Kataria, 2011). The study is a CASE Award PhD thesis, requiring academic and practical elements to the research. The study is of one case organisation, focusing on one service characterised by a high level of adoption of Strategic Human Resource Management activities and operating in a rather unique manner for the public sector, having private sector competition for work. The study involved a mixed methods approach to data collection. Preliminary focus groups with 45 participants were conducted, followed by an ethnographic period of five months embedded into the service conducting interviews and observations. This culminated in a quantitative survey delivered within the wider directorate to approximately 500 staff members. The study used aspects of the Grounded Theory (Glaser & Strauss, 1967) approach to analyse the data and developed results that highlight the importance of the line manager in an area characterised by SHRM and organisational change for engaging employees and encouraging innovative behaviour. This survey was completed on behalf of the organisation and the findings of this are presented in appendix 1, in order to keep the focus of the PhD on theory development. Implications for theory and practice are discussed alongside the core finding. Line managers’ discretion surrounding the provision of job resources (in particular trust, autonomy and implementation and interpretation of combined bundles of SHRM policies and procedures) influenced the exchange process by which employees responded with work engagement and innovative behaviour. Limitations to the research are the limitations commonly attributed to cross-sectional data collection methods and those surrounding generalisability of the qualitative findings outside of the contextual factors characterising the service area. Suggestions for future research involve addressing these limitations and further exploration of the discretionary role with regards to extending our understanding of line manager discretion.

A legal perspective of integrated surface mining, solid waste landfill reclamation and land conservation

In the area of international environmental law this thesis proposes the formulation of one-step planning and permitting regulation for the integrated utilisation of new surface mines as depositories for municipal solid waste. Additionally, the utilisation of abandoned and currently operated surface mines is proposed as solid waste landfills as an integral step in their reclamation. Existing laws, litigation and issues in the United Kingdom, the U.S. and Canada are discussed because of their common legal system, language and heritage. The critical shortage of approved space for disposal of solid waste has caused an urgent and growing problem for both the waste disposal industry and society. Surface mining can serve three important environmental and societal functions inuring to the health and welfare of the public: (1) providing basic minerals for goods and construction; (20 sequentially, to provide critically needed, safe burial sites for society's wastes, and (3) to conserve land by dual purpose use and to restore derelict land to beneficial surface use. Currently, the first two functions are treated environmentally, and in regulation, as two different siting problems, yet they both are earth-disturbing and excavating industries requiring surface restoration. The processes are largely duplicative and should be combined for better efficiency, less earth disturbance, conservation of land, and for fuller and better reclamation of completed surface mines returning the surfaces to greater utility than present mined land reclamation procedures. While both industries are viewed by a developed society and its communities as "bad neighbours", they remain essential and critical for mankind's existence and welfare. The study offers successful examples of the integrated process in each country. The study argues that most non-fuel surface mine openings, if not already safe, can economically, through present containment technology, be made environmentally safe for use as solid waste landfills. Simultaneously, the procedure safeguards and monitors protection of ground and surface waters from landfill contamination.

Nanoporous solid acid and base catalysts for sustainable biofuels production

Dwindling fossil fuel reserves, and growing concerns over CO2 emissions and associated climate change, are driving the quest for renewable feedstocks to provide alternative, sustainable fuel sources. Catalysis has a rich history of facilitating energy efficient, selective molecular transformations, and in a post-petroleum era will play a pivotal role in overcoming the scientific and engineering barriers to economically viable, and sustainable, biofuels derived from renewable resources. The production of second generation biofuels, derived from biomass sourced from inedible crop components, e.g. agricultural or forestry waste, or alternative non-food crops such as Switchgrass or Jatropha Curcas that require minimal cultivation, necessitate new heterogeneous catalysts and processes to transform these polar and viscous feedstocks [1]. Here we show how advances in the rational design of nanoporous solid acids and bases, and their utilisation in novel continuous reactors, can deliver superior performance in the energy-efficient esterification and transesterification of bio-oil components into biodiesel [2-4]. Notes: [1] K. Wilson, A.F. Lee, Cat. Sci. Tech. 2012 ,2, 884. [2] J. Dhainaut, J.-P. Dacquin, A. F. Lee, K. Wilson, Green Chem. 2010 , 12, 296. [3] C. Pirez, J.-M. Caderon, J.-P. Dacquin, A.F. Lee, K. Wilson, ACS Catal. 2012 , 2, 1607. [4] J.J. Woodford, J.-P. Dacquin, K. Wilson, A.F. Lee, Energy Environ. Sci. 2012 , 5, 6145.

Drying kinetic analysis of municipal solid waste using modified page model and pattern search method

This work studied the drying kinetics of the organic fractions of municipal solid waste (MSW) samples with different initial moisture contents and presented a new method for determination of drying kinetic parameters. A series of drying experiments at different temperatures were performed by using a thermogravimetric technique. Based on the modified Page drying model and the general pattern search method, a new drying kinetic method was developed using multiple isothermal drying curves simultaneously. The new method fitted the experimental data more accurately than the traditional method. Drying kinetic behaviors under extrapolated conditions were also predicted and validated. The new method indicated that the drying activation energies for the samples with initial moisture contents of 31.1 and 17.2 % on wet basis were 25.97 and 24.73 kJ mol−1. These results are useful for drying process simulation and industrial dryer design. This new method can be also applied to determine the drying parameters of other materials with high reliability.

The development of a solid waste management strategy

This research is concerned with the application of operational research techniques in the development of a long- term waste management policy by an English waste disposal authority. The main aspects which have been considered are the estimation of future waste production and the assessment of the effects of proposed systems. Only household and commercial wastes have been dealt with in detail, though suggestions are made for the extension of the effect assessment to cover industrial and other wastes. Similarly, the only effects considered in detail have been costs, but possible extensions are discussed. An important feature of the study is that it was conducted in close collaboration with a waste disposal authority, and so pays more attention to the actual needs of the authority than is usual in such research. A critical examination of previous waste forecasting work leads to the use of simple trend extrapolation methods, with some consideration of seasonal effects. The possibility of relating waste production to other social and economic indicators is discussed. It is concluded that, at present, large uncertainties in predictions are inevitable; waste management systems must therefore be designed to cope with this uncertainty. Linear programming is used to assess the overall costs of proposals. Two alternative linear programming formulations of this problem are used and discussed. The first is a straightforward approach, which has been .implemented as an interactive computer program. The second is more sophisticated and represents the behaviour of incineration plants more realistically. Careful attention is paid to the choice of appropriate data and the interpretation of the results. Recommendations are made on methods for immediate use, on the choice of data to be collected for future plans, and on the most useful lines for further research and development.

Evaluation of options for energy recovery from municipal solid waste in India using the hierarchical analytical network process

In this paper a Hierarchical Analytical Network Process (HANP) model is demonstrated for evaluating alternative technologies for generating electricity from MSW in India. The technological alternatives and evaluation criteria for the HANP study are characterised by reviewing the literature and consulting experts in the field of waste management. Technologies reviewed in the context of India include landfill, anaerobic digestion, incineration, pelletisation and gasification. To investigate the sensitivity of the result, we examine variations in expert opinions and carry out an Analytical Hierarchy Process (AHP) analysis for comparison. We find that anaerobic digestion is the preferred technology for generating electricity from MSW in India. Gasification is indicated as the preferred technology in an AHP model due to the exclusion of criteria dependencies and in an HANP analysis when placing a high priority on net output and retention time. We conclude that HANP successfully provides a structured framework for recommending which technologies to pursue in India, and the adoption of such tools is critical at a time when key investments in infrastructure are being made. Therefore the presented methodology is thought to have a wider potential for investors, policy makers, researchers and plant developers in India and elsewhere. © 2013 Elsevier Ltd. All rights reserved.

Energy conversion assessment of vacuum, slow and fast pyrolysis processes for low and high ash paper waste sludge

The performance of vacuum, slow and fast pyrolysis processes to transfer energy from the paper waste sludge (PWS) to liquid and solid products was compared. Paper waste sludges with low and high ash content (8.5 and 46.7 wt.%) were converted under optimised conditions for temperature and pellet size to maximise both product yields and energy content. Comparison of the gross energy conversions, as a combination of the bio-oil/tarry phase and char (ECsum), revealed that the fast pyrolysis performance was between 18.5% and 20.1% higher for the low ash PWS, and 18.4% and 36.5% higher for high ash PWS, when compared to the slow and vacuum pyrolysis processes respectively. For both PWSs, this finding was mainly attributed to higher production of condensable organic compounds and lower water yields during FP. The low ash PWS chars, fast pyrolysis bio-oils and vacuum pyrolysis tarry phase products had high calorific values (∼18-23 MJ kg-1) making them promising for energy applications. Considering the low calorific values of the chars from alternative pyrolysis processes (∼4-7 MJ kg-1), the high ash PWS should rather be converted to fast pyrolysis bio-oil to maximise the recovery of usable energy products.