Ian Ernest Maxwell
Royal Dutch Shell
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Studies in Surface Science and Catalysis | 2001
Ian Ernest Maxwell; W.H.J. Stork
Abstract This chapter on hydrocarbon processing with zeolites covers both existing and new catalytic applications of zeolites in oil refining and gas conversion. By way of introduction some structural aspects related to these industries are discussed to provide some background in which to relate the current and future developments. Further, the unique opportunities and limitations of zeolites are discussed in order to put the applications in hydrocarbon processing into perspective. Some more evolutionary type developments are covered where the introduction and continued improvement of zeolite catalysts have had a significant impact on existing process technologies. Examples of such technologies in this category include catalytic cracking, hydrocracking, paraffin isomerization and olefin oligomerization. Newer process technologies in which the application of zeolitic catalysts has led to new process concepts are also included. The unique shape selective properties of zeolites are shown to play a dominant role in this developing field of applications. Examples include catalytic iso-dewaxing, LPG to aromatics (CYCLAR), selective oxidation, methanol-toolefins (MTO), deep catalytic cracking (DCC) and selective catalytic NOx removal (SCR). Finally, some general trends are discussed in terms of zeolite catalysis and how these might be expected to have a further impact on hydrocarbon process technology in the future. Significant opportunities are believed to exist for further developments related to both existing and emerging processes. The discovery and application of new synthetic molecular sieves, leading to new or rejuvenated processes, also holds promise for the future. In addition, advances in understanding are being achieved by the recent emphasis on theoretical studies, while the emerging combinatorial synthesis and high-speed screening technologies represent a great increase in experimental power over the time-consuming and empirical approaches employed hitherto.
Journal of Inclusion Phenomena and Macrocyclic Chemistry | 1986
Ian Ernest Maxwell
The use of zeolites in shape-selective catalysis is a field which has experienced rapid growth in recent years both as regards the development of new concepts and the applications in petrochemical process technology. This review article is intended to introduce the catalytic concepts and process technology involved, with ample use of examples, rather than to provide a comprehensive coverage of the field.An introduction to the subject matter is given by discussing zeolite composition and structure, active sites for catalysis and diffusion phenomena. The various types of shape selective catalysis are discussed, i.e., reactant, restricted transition state and product selectivity. The process technology discussion covers topics such as catalytic dewaxing, methanol conversion and aromatics synthesis. Finally, future trends are discussed which indicate that there is scope for further exciting developments in shape-selective catalytic chemistry and applications in process technology.
Nature | 1998
Ian Ernest Maxwell
The pharmaceutical industry has for several years successfully used a combinatorial approach in drug development. The technique involves the micro-scale synthesis and screening of organic molecules for activity, and is now being applied in other areas. One such is the development of better systems for heterogeneous catalysis, and new work provides proof of principle that the combinatorial route may prove highly productive here also.
Studies in Surface Science and Catalysis | 1996
Ian Ernest Maxwell
Publisher Summary Catalytic environmental technologies such as automobile exhaust catalysts and the selective catalytic reduction (SCR) DeNOx systems in power plants have significantly contributed to the reduction of environmentally harmful emissions into the lower atmosphere. Some studies have identified catalysis as not only being pervasive but also offering significant scope for the innovative development of new and improved technologies for environmentally acceptable processes and products in the future. The spectrum of process industries that are directly impacted by catalysis include, for example, oil refining, natural gas conversion, petrochemicals, fine chemicals, and pharmaceuticals. Environmental catalytic technologies also play an important role in emission control systems for power generation, fossil fuel driven transportation, oil refining, and chemical industries. Catalytic technologies typically embrace a wide range of disciplines, such as heterogeneous and homogeneous catalysis, materials science, process technology, reactor engineering, separation technology, surface science, computational chemistry, and analytic chemistry. Innovation in this field is, therefore, often achieved by lateral thinking across these different disciplines. This chapter attempts to develop this theme by means of examples from recent commercial successes and from this platform provides some guidelines for multi-disciplinary approaches at the academic and industrial interface to enhanced innovation in catalytic technologies in the future.
Studies in Surface Science and Catalysis | 1989
A.A. Esener; Ian Ernest Maxwell
Abstract A stacked bed hydrocracker reactor configuration composed of conventional hydrotreating and zeolite–based catalysts is shown to offer marked improvements in performance compared to single bed systems. Significant gains in overall hydrocracking activity are achieved, together with good catalyst stability, which is characteristic of zeolitic catalysts. The overall hydrocracking and hydrodenitrogenation kinetics can be described using Langmuir–Hinshelwood type kinetics. Inter–catalyst organic nitrogen levels are shown to play an important role due to their strong inhibiting effect on the activity of the zeolite catalyst. A newly developed zeolitic catalyst (S703) is shown to exhibit a marked improvement in middle distillate selectivity compared to previous, more conventional zeolite–based systems (S753). The product qualities obtained are shown to be quite acceptable, particularly at high conversion levels.
Current Opinion in Solid State & Materials Science | 1996
Ian Ernest Maxwell; Peter William Lednor
Abstract Materials science plays an important role in the field of applied catalysis. Recent developments have been made in research related to catalytic materials as applied to catalytic processes for oil refining, chemicals synthesis, natural gas conversion and environmental technology. Future development of catalytic materials will be required to enhance the performance of catalyst systems for application in catalytic combustion, synthesis gas manufacturing, lean burn auto emission control and paraffin alkylation and at the interface between homogeneous and heterogeneous catalysis.
Chemical Engineering Science | 1990
H. van der Eijk; G. J. den Otter; P.M.M. Blauwhoff; Ian Ernest Maxwell
Abstract The complexity of oil refining increases with the current tendency to convert heavy feedstocks into lighter products and to enhance product quality. This calls for an improved understanding not only of the basics of the individual processes but also of their interrelationships and hence of the synergistic effects to be expected from multiprocess integration. Another trend is towards investigating even the most complex oil processes at the molecular level. This includes the characterization of both feedstocks and products in terms of individual or grouped molecular components. This approach has been shown to facilitate process integration and to result in the development of process models which are more soundly based on physical/chemical principles and are thus more powerful than the conventional models. The validity of this approach is substantiated by process integration studies, the use of catalyst modules, product quality/performance correlations and model validations both in the laboratory and in the refinery. It is perceived that process models will play an increasingly important role in the transfer of technology between the laboratory and the design office. A major challenge in the future will be to develop models which can also contribute to the innovative phase in the research laboratory.
Studies in Surface Science and Catalysis | 1989
J. Biswas; Ian Ernest Maxwell
Fluid catalytic cracking (FCC) is a fundamental upgrading process in present crude oil refining. With the advent of gasoline lead legislation, emphasis has been placed on the development of techniques to enhance gasoline octane numbers, especially the motor octane number (MON). With a view to investigating the fundamental chemistry/process interactions a number of variables have been studied: –the use of low unit cell size, ultra-stable Y FCC catalysts –the use of high reactor temperatures –addition of ZSM-5 to induce shape-selective cracking of low-octane components to gas –operation at high conversion levels. Catalyst developments suggest that it might be useful to apply controlled carbonium ion activity and hydrogen transfer to enhance olefin cyclization to aromatics as well as isomerization to isoparaffins. Operation at high temperatures and operation at high conversions (high catalyst/oil ratios) are seen to favour aromatics formation from cyclization reactions. Application of FCC additives for the shape-selective cracking of paraffinic gasoline components to gas increases the aromatics concentration, thus improving the octane levels.
Studies in Surface Science and Catalysis | 1986
Ian Ernest Maxwell; J.A. van de Griend
As a part of a study aimed at providing a more basic understanding of hydrodenitrogenation (HDN) catalysts, a kinetic study has been carried out using quinoline as a model feedstock and a bifunctional catalyst containing zeolite Y. The results show that the overall kinetics of quinoline HDN can be well described by means of a Langmuir-Hinshelwood type of relationship. This implies that there is relatively strong adsorption of N-containing intermediate and/or product molecules on the catalyst surface, which further plays a dominant role in determining the overall rate of HDN. The relatively simple model developed can be used, for example, to calculate the overall steady-state coverage of the catalyst surface with N-components under various reaction conditions. This type of approach could be used to develop a better insight into the relationship between catalyst physical/chemical properties and HDN kinetic parameters.
Nature | 1998
Ian Ernest Maxwell
The pharmaceutical industry has for several years successfully used a combinatorial approach in drug development. The technique involves the micro-scale synthesis and screening of organic molecules for activity, and is now being applied in other areas. One such is the development of better systems for heterogeneous catalysis, and new work provides proof of principle that the combinatorial route may prove highly productive here also.