Once the shovel hits the ground : Evaluating the management of complex implementation processes of public-private partnership infrastructure projects with qualitative comparative analysis

Much attention is being paid to the planning of public-private partnership (PPP) infrastructure projects. The subsequent implementation phase – when the contract has been signed and the project ‘starts rolling’ – has received less attention. However, sound agreements and good intentions in project planning can easily fail in project implementation. Implementing PPP infrastructure projects is complex, but what does this complexity entail? How are projects managed, and how do public and private partners cooperate in implementation? What are effective management strategies to achieve satisfactory outcomes? This is the fi rst set of questions addressed in this thesis. Importantly, the complexity of PPP infrastructure development imposes requirements on the evaluation methods that can be applied for studying these questions. Evaluation methods that ignore complexity do not create a realistic understanding of PPP implementation processes, with the consequence that evaluations tell us little about what works and what does not, in which contexts, and why. This hampers learning from evaluations. What are the requirements for a complexity-informed evaluation method? And how does qualitative comparative analysis (QCA) meet these requirements? This is the second set of questions addressed in this thesis

Influence of carbon deposits on the cobalt-catalyzed Fischer-Tropsch reaction: evidence of a two-site reaction model

\u3cp\u3eOne of the well-known observations in the Fischer-Tropsch (FT) reaction is that the CH\u3csub\u3e4\u3c/sub\u3e selectivity for cobalt catalysts is always higher than the value expected on the basis of the Anderson-Schulz-Flory (ASF) distribution. Depositing graphitic carbon on a cobalt catalyst strongly suppresses this non-ASF CH\u3csub\u3e4\u3c/sub\u3e, while the formation of higher hydrocarbons is much less affected. Carbon was laid down on the cobalt catalyst via the Boudouard reaction. We provide evidence that the amorphous carbon does not influence the FT reaction, as it can be easily hydrogenated under reaction conditions. Graphitic carbon is rapidly formed and cannot be removed. This unreactive form of carbon is located on terrace sites and mainly decreases the CO conversion by limiting CH\u3csub\u3e4\u3c/sub\u3e formation. Despite nearly unchanged higher hydrocarbon yield, the presence of graphitic carbon enhances the chain-growth probability and strongly suppresses olefin hydrogenation. We demonstrate that graphitic carbon will slowly deposit on the cobalt catalysts during CO hydrogenation, thereby influencing CO conversion and the FT product distribution in a way similar to that for predeposited graphitic carbon. We also demonstrate that the buildup of graphitic carbon by \u3csup\u3e13\u3c/sup\u3eCO increases the rate of C-C coupling during the \u3csup\u3e12\u3c/sup\u3eC\u3csub\u3e3\u3c/sub\u3eH\u3csub\u3e6\u3c/sub\u3e hydrogenation reaction, whose products follow an ASF-type product distribution of the FT reaction. We explain these results by a two-site model on the basis of insights into structure sensitivity of the underlying reaction steps in the FT mechanism: carbon formed on step-edge sites is involved in chain growth or can migrate to terrace sites, where it is rapidly hydrogenated to CH\u3csub\u3e4\u3c/sub\u3e. The primary olefinic FT products are predominantly hydrogenated on terrace sites. Covering the terraces by graphitic carbon increases the residence time of CH\u3csub\u3ex\u3c/sub\u3e intermediates, in line with decreased CH\u3csub\u3e4\u3c/sub\u3e selectivity and increased chain-growth rate.\u3c/p\u3

Synthesis of stable and low-CO2 selective ε-iron carbide Fischer-Tropsch catalysts

The Fe-catalyzed Fischer-Tropsch (FT) reaction constitutes the core of the coal-to-liquids (CTL) process, which converts coal into liquid fuels. Conventional Fe-based catalysts typically convert 30% of the CO feed to CO2 in the FT unit. Decreasing the CO2 release in the FT step will reduce costs and enhance productivity of the overall process. In this context, we synthesize phase-pure ε(′)-Fe2C catalysts exhibiting low CO2 selectivity by carefully controlling the pretreatment and carburization conditions. Kinetic data reveal that liquid fuels can be obtained free from primary CO2. These catalysts displayed stable FT performance at 23 bar and 235°C for at least 150 hours. Notably, in situ characterization emphasizes the high durability of pure ε(′)-Fe2C in an industrial pilot test. These findings contribute to the development of new Fe-based FT catalysts for next-generation CTL processes

ANALYSING THE SUCCESS OF OPEN SPACE PRESERVATION IN THE NETHERLANDS: THE MIDDEN-DELFLAND CASE

Open space preservation is an important aim of spatial planning. In the Netherlands, the recreational, ecological and historic values of open spaces between cities, the buffer zones, are recognised and thus receive ample attention from policy-makers. This paper focuses on Midden-Delfland, an open area in the metropolitan western part of the country. A specific combination of policy instruments and government regulation has made the preservation of open space in this area very successful even compared to other buffer zones. A quantitative analysis of the land-use changes and a more qualitative review of the applied policy instruments are presented here in an attempt to explain this success. The analysis can help planners in finding ways to effectively protect contested open areas. Copyright (c) 2008 by the Royal Dutch Geographical Society KNAG.