Catalytic technology

By the mid-1930s, catalytic technology entered into petroleum refining. To a greater extent than thermal cracking, catalysis permitted the close control of the rate and direction of reaction. It minimized the formation of unwanted side reactions, such as carbon formation, and overall improved the yield and quality of fuel output. 

An improved design undertaken by Sacony used high-velocity gases to replace the mechanical elevator systems as catalyst carriers. These so-called air-lift units improved upon the Thermofor process both in terms of economies and octane numbers. It was, however, only with the fluid cracking process that catalytic technology realized fully continuous production. 

The plasma-catalyst system utilizes plasma to oxidize NO to NO2 which then reacts with a suitable reductant over a catalyst however, this plasma-assisted catalytic technology still comprises challenging tasks to resolve the formation of toxic by-products and the catalyst deactivation due to the deposition of organic products during the course of the reaction as well as to prepare cost effective and durable on-board plasma devices [47]. 

The three-way catalyst, consisting of Pt and Rh particles supported on a ceramic monolith, represents a remarkably successful piece of catalytic technology. It enables the removal of the three pollutants CO, NO and hydrocarbons by the following overall reactions (Tab. 10.3) ... 

The three-way catalyst and the NOx storage-reduction catalyst represent remarkably successful catalytic technology. The catalysts are unique in that they have to operate under a wide range of conditions, depending on type of use, personal driving style, local climate, etc. This in contrast to the usual situation in industry, where conditions are optimized and kept constant. 

Figure 1. Disciplines of Prime Importance to Catalytic Technologies... 

Thus, in order to fully realize the potential of catalytic technologies not only will this require technical innovation in multi-disciplinary teams but also the appropriate organizational structures which maximize the synergies between academic and industrial research. The countries which recognize this potential and provide the... 

The author is most grateful for the valuable discussions with many of his Shell research colleagues in the field of catalytic technologies. In particular, as relate to this paper, discussions with Dr. G. Boxhoorn, Dr. K. de Jong, Ir. J. Naber and Dr. W. Stork are gratefully acknowledged. 

Catalytic polymerization is surveyed in Heinemann s paper on advances in catalytic technology. 

Another important catalytic technology for removal of NOx from lean-burn engine exhausts involves NOx storage reduction catalysis, or the lean-NOx trap . In the lean-NOx trap, the formation of N02 by NO oxidation is followed by the formation of a nitrate when the N02 is adsorbed onto the catalyst surface. Thus, the N02 is stored on the catalyst surface in the nitrate form and subsequently decomposed to N2. Lean NOx trap catalysts have shown serious deactivation in the presence of SOx because, under oxygen-rich conditions, SO, adsorbs more strongly on N02 adsorption sites than N02, and the adsorbed SOx does not desorb altogether even under fuel-rich conditions. The presence of S03 leads to the formation of sulfuric acid and sulfates that increase the particulates in the exhaust and poison the active sites on the catalyst. Furthermore, catalytic oxidation of NO to N02 can be operated in a limited temperature range. Oxidation of NO to N02 by a conventional Pt-based catalyst has a maximum at about 250°C and loses its efficiency below about 100°C and above about 400°C. 

As an example, when automotive catalytic mufflers and converters were introduced many years ago, the automobile industry required the petrochemical industry to eliminate lead from gasoline since lead degraded and reduced the effectiveness of the catalyst and caused the destruction of the gasoline. One set of industrial compounds that can harm catalysts are halogens, a family of compounds that include chlorine, bromine, iodine, and fluorine. Bromine, while not prevalent in industry, is present in chemical plants. Freons are fluorine compounds. Silicone is another compound that is deleterious to catalysts. It is used as a slip agent, or a lubricant, in many industrial processes. Phosphorous, heavy metals (zinc, lead), sulfur compounds, and any particulate can result in shortening the life of the catalyst. It is necessary to estimate the volume or the amount of each of those contaminants, to assess the viability of catalytic technologies for the application. 

The chapters that follow are based on lectures presented at the Idecat conference on Catalysis for Renewables , Rolduc, The Netherlands, which had been organized to discuss different technology options and related catalytic advances or challenges. Whereas the main focus is on biomass related catalytic technologies, lectures on fossil fuel technology as well as solar and biotechnological conversion paths were also included. 

Renewable Catalytic Technologies - a Perspective Primary energy Secondary energy... 

The present chapter discusses aspects, known by the authors, of (a) biomass as feedstock, (b) the concept of bio-refinery, (c) thermochemical routes from lignocellulosic biomass to fuels, and (d) the contribution of catalytic technology. The main focus will be on the catalytic conversion of fast pyrolysis oil into fuels with regard to problems encountered currently and the challenges for future research and development. 

---