Catalyst development time

For a long time practical catalysis remained an empirical art rather than a scientific discipline, mainly because the complexity of the catalytic systems obscured the molecular insights needed for their control in a predictive manner. The modern spectroscopic techniques available to the analytical laboratory enable detailed catalyst analysis and in-situ studies. Advanced inorganic and organometallic chemistry and catalyst synthesis (e.g. zeolite synthesis) are also significant. This has changed catalytic practice and has resulted in a considerable reduction of catalyst development times. Nonetheless, in catalysis, accidental discovery and high risk exploratory research are still important factors in innovation. 

Oxychlorination of methane can yield significant amounts of methylene chloride. A number of patents were obtained by Lummus in the mid-1970s on a high temperature, molten salt oxychlorination process (22,23). Catalyst development work has continued and generally consists of mixtures of Cu, Ni, Cr, or Fe promoted with an alkah metal (24—27). There are no industrial examples of this process at the present time. 

Catalytic Pyrolysis. This should not be confused with fluid catalytic cracking, which is used in petroleum refining (see Catalysts, regeneration). Catalytic pyrolysis is aimed at producing primarily ethylene. There are many patents and research articles covering the last 20 years (84—89). Catalytic research until 1988 has been summarized (86). Almost all catalysts produce higher amounts of CO and CO2 than normally obtained with conventional pyrolysis. This indicates that the water gas reaction is also very active with these catalysts, and usually this leads to some deterioration of the olefin yield. Significant amounts of coke have been found in these catalysts, and thus there is a further reduction in olefin yield with on-stream time. Most of these catalysts are based on low surface area alumina catalysts (86). A notable exception is the catalyst developed in the former USSR (89). This catalyst primarily contains vanadium as the active material on pumice (89), and is claimed to produce low levels of carbon oxides. 

A major step in catalyst development was the introduction of crystalline zeolitic, or molecular sieve catalysts. Their activity is very high, some of the active sites being estimated at 10,000 times the effectiveness of amorphous silica-... 

Serious research in catalytic reduction of automotive exhaust was begun in 1949 by Eugene Houdry, who developed mufflers for fork lift trucks used in confined spaces such as mines and warehouses (18). One of the supports used was the monolith—porcelain rods covered with films of alumina, on which platinum was deposited. California enacted laws in 1959 and 1960 on air quality and motor vehicle emission standards, which would be operative when at least two devices were developed that could meet the requirements. This gave the impetus for a greater effort in automotive catalysis research (19). Catalyst developments and fleet tests involved the partnership of catalyst manufacturers and muffler manufacturers. Three of these teams were certified by the California Motor Vehicle Pollution Control Board in 1964-65 American Cyanamid and Walker, W. R. Grace and Norris-Thermador, and Universal Oil Products and Arvin. At the same time, Detroit announced that engine modifications by lean carburation and secondary air injection enabled them to meet the California standard without the use of catalysts. This then delayed the use of catalysts in automobiles. 

Of particular concern was the finding of a suitable catalyst Owing to the scouting nature, virtually no know-how base was available that time. The investigation gave highly valuable hints for later catalyst development. Actually, they motivated a search for catalysts of higher porosity and better defined composition. As a result, anodically oxidized alumina supports for catalysts were developed (see Sections 3.1 and 3.4.2). 

Reports have shown solid catalysts for esterification of FFA have one or more problems such as high cost, severe reaction conditions, slow kinetics, low or incomplete conversions, and limited lifetime. We will present research describing our newly developed polymeric catalyst technology which enables the production of biodiesel from feedstock containing high levels (> 1 wt %) of FFAs. The novel catalyst, named AmberlysH BD20, overcomes the traditional drawbacks such as limited catalyst life time, slow reaction rates, and low conversions. 

Improved Filtration Rate Filterability is an important powder catalyst physical property. Sometimes, it can become more important than the catalyst activity depending on the chemical process. When a simple reaction requires less reaction time, a slow filtration operation can slow down the whole process. From a practical point of view, an ideal catalyst not only should have good activity, but also it should have good filtration. From catalyst development point of view, one should consider the relationship between catalyst particle size and its distribution with its catalytic activity and filterability. Smaller catalyst particle size will have better activity but will generally result in slower filtration rate. A narrower particle size distribution with proper particle size will provide a better filtration rate and maintain good activity. 

It has been ten years since Amoco announced the UltraCat process O) for SOx control in FCC units. In those ten years, as well as in the years previous to the announcement, much work was done to develop catalysts that would control SOx emissions. The evidence is the 80 or more U.S. patents that have issued in that time to Amoco and others. One of the first patents issued was to Amoco in 1974 ( ) for the addition of magnesia and other group IIA oxides to cracking catalyst. This paper reviews the SOx catalyst developments and emphasizes the work done at Amoco to identify the active materials, explain the deactivation mechanism and, finally, to make a side-by-side comparison of various catalytic systems that are being pursued commercially today. 

As the models presented in this chapter are relatively complex, they are not used for control purposes in their current status. They can however be used for the development of control models, either by linearization and simplification, or as virtual test bench . This way, a control model is pre-tuned on the catalyst or system model before parameterization on the real test bench, thus saving development time and costs. 

To put these problems into perspective, as already discussed, the PASCs remaining at the 0.20% S level are lower in reactivity, by a factor of 10-50, than the sulfur compounds that are now removed in lowering the sulfur level from 1.2 to 0.20%, Even with catalysts 2 times as active, the reactor volume may have to be doubled to convert the required 75% of the least-reactive PASCs to achieve the 0.05% S target. Based on the composition of a typical gas oil and using the first-order rate constants for the different classes of sulfur compounds (14), a theoretical HDS severity plot is presented in Fig. 9. It can be seen that reactor volumes will have to be increased by about a factor of 4 to meet the new specifications unless much more active catalysts can be developed than are presently available. 

A gas-phase alkylation over an alumina-supported BF3 catalyst developed by UOP (Alkar process)312,313 reduces the corrosion problems associated with liquid-phase alkylation processes. An advantage of this technology is that it utilizes very dilute (8-10%) ethylene streams, such as refinery fuel gases (cracked gas streams). At the same time, to properly support BF3 is difficult. 

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