Fluid catalysts commercial performance

The PFR is efficient for screening solid catalyst in a single fluid phase. It can also be used in later research stages to assess commercial criteria. Consider the evaluation of the ultimate commercial performance of a newly developed fixed-bed catalyst. The theory of similarity teaches that for the laboratory and the industrial reactor, the Damkohler number (NDa), the Sherwood number (Nsh), and the Thiele modulus (<)>) need to be kept constant (Figure 2). As a result, the laboratory reactor must have the same length as the envisioned commercial reactor (7). In this case, scale up is done by increasing the diameter of the reactor. This example further illustrates that laboratory reactors are not necessarily small in size. 

Figure 2.2.1 shows the simplified sketch of the reactor used for the microactivity test. As can be seen, a fluid-bed catalyst is tested in a fixed bed reactor in the laboratory to predict its performance in a commercial fluid bed reactor. This can be done only because enormous empirical experience exists that has accumulated throughout several decades in several hundreds of reactors both in production and in laboratories. The standard states ... 

The two catalysts reporetd here, both commercial VOC oxidation catalysts, are a cerium-promoted Hopcalite (Catalyst A), and a chromia/alumina (Catalyst B). catalyst B was designed primarialy for fluid-bed operation, but has been studied here in both fixed-and fluid-bed application. Catalyst A has been studied only in fixed-bed studies Further data on these materials, as well on the performance of a Pt/Ni/alumina catalyst, are given in [2]. 

The chapters in Characterization and Catalyst Development An Interactive Approach, assembled from both academic and industrial contributors, give a unique perspective on catalyst development Some chapters thoroughly characterize the catalyst prior to plant evaluation, whereas others utilize characterization to explain performance variances. Some new types of catalysts incorporated into this volume include the preparation of novel catalyst supports based on alumina and hydrous titanates. Attrition-resistant catalysts and ultrafine ceramics were prepared by modified spray-drying methods. New catalyst compositions based on vanadium-containing anionic clays were proposed for oxidation. A recently commercialized catalyst based on magnesium spinel was proposed for use in the abatement of sulfur oxide pollutants in fluid... 

Vanadium, while not the only contributor to fluid cracking catalyst (FCC) deactivation, frequently dictates the amount of fresh catalyst added to the FCC unit to mmntain activity. Improvements have been made to both zeolites and matrices to minimize the effect of vanadium [1]. Another method of protecting the catalyst from vanadium deactivation is to use traps that prevent the vanadium from contacting the catalyst in the first place. Vanadium traps have frequently shown more promise in laboratory testing than has been realized commercially[2,3]. Sulfur, present in commercial operations, has been known to interfere with previous traps ability to capture vanadium. Recently it has been shown vanadium traps can be designed to perform successfully under commercial conditions. 

For every commercial catalyst an optimal combination of unit operation sequence exists for the manufacture of that specific catalyst and there will for each unit operation exist preferential process equipment, i.e. fluid bed calciner for calcination. The sequence of unit operations with the special selection of process equipment and all process parameters forms the know-how for manufacturing a catalyst product of large commercial value. But know-how does not mean that you always know why the desired properties are obtained due to the insufficient scientific characterisation of the catalyst material as described above under 2.1. Even small adjustments of the process can change strength, pore size distribution, bulk density, crystallite size etc. of the product and, thus, harm the performance in the industrial reactor. It has normally been costly and time-consuming to reach the final recipe and, therefore, all catalyst companies want to keep it secret. If a single unit operation is changed it will often influence the optimisation of most of the other unit operations, and much of the development will have to be redone. 

In the early years, the petroleum industry acted as a catalyst for the development of this physical method. However, over the past twenty-five years, organic mass spectrometry has been the subject of a series of major developments. Some of them, such as the advent of commercially available interfaces for gas-liquid, high performance liquid, and supercritical fluid chromatographs, as well as novel ionisation techniques particularly well suited for high molecular weight, non-volatile macromolecules were welcome and well-accepted by the food analysts. Others, such as the introduction of relatively inexpensive quadrupole mass filters that proved to be reliable and... 

Metallocene LLDPEs are relatively difficult to process because of narrow molecular weight distribution (MWD) when compared to conventional Ziegler LLDPEs. Metallocene catalyst based octene-1 LLDPE copolymers made by the Dow Chemical Company are known to process better as a result of their long-chain branched (LCB) structure, referred to as Dow Rheology Index (DRI) numbers.The LCB is also responsible for improved melt strength in mLLDPEs.Exxon has also addressed the processibility issue with advanced performance terpolymers.LCB bimodal mLLDPE resins are commercially available from BP Chemicals.Such mLLDPEs are produced by BP s proprietary gas phase fluid bed technology called Innovene technology. 

A series of experiments varying temperature, micro-sphere size and time on stream have been performed in a fixed fluidised bed microactivity reactor to study the role of intraparticle diffusion in commercial fluid catalytic cracking (FCC) catalysts, particularly on gasoline yield and catalyst deactivation by coke deposition, for the cracking of a vacuum gas oil. Additionally, a mechanistic model that describes interface and intrapartide mass transfer interactions with the cracking reactions, has been used to study the combined influence of pore size and intraparticle mass diffusion on the deactivation of FCC catalysts and the gasoline yield. 

Industrial production is based on 50% solutions of D-glucose (dextrose). The yield of s. depends strictly on the purity of the sugar. Hydrogenation is performed continuously under high pressure on fixed-bed Cu-oxide or Ni-oxide catalysts. After refining, the reaction fluid is evaporated to 70% d.s. (main commercial product). S. powder may be prepared by (spray)crystallization of highest-purity s. 

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