Solids techniques

Several processes based on non-precious metal also exist. Because of high catalyst deactivation rates with these catalyst systems, they all require some form of continuous regeneration. The Fluid Hydroforming process uses fluid solids techniques to move catalyst between reactor and regenerator TCR and Hyperforming use some form of a moving bed system. 

The use of the fluidised solids technique was developed mainly by the petroleum and chemical industries, for processes where the very high heat transfer coefficients and the... 

Equally important is the salt formation of solid bases with gaseous acids. An example has been cited above (30 31). This type of reaction is quite general. Strong and very weak bases react quantitatively and the gas-solid technique does not have problems with moisture. Amino acids such as L-phenylalanine, D-penicillamine (42), DL-penicillamine, L-cysteine, L-leucine, L-proline, DL-ty-rosine and others are quantitatively converted into their hydrohalides with... 

The gas-solid technique is particularly attractive in the synthesis of extremely sensitive hydrohalogenides of Schiff bases (e.g., 54) as the exclusion of moisture is automatically achieved. Some of these salts include additional HX, which cannot be completely removed by evacuation and the phenolic compounds keep a second mole of HX that cannot be evaporated (Table 1, Scheme 6) [9]. 

A big advantage of the solid-solid technique is the possibility of obtaining complexes that are not obtainable from solution. It must, however, be shown that uniform complexes rather than microcrystalline mixtures occur. Apart from X-ray powder diffraction (which does not properly account for very small crystallites), proof is obtained by solid-state spectroscopy (IR, UV, luminescence) or, in the case of stable radicals, by magnetic susceptibility measurements. The 1 1 and 2 1 complexes 68-72 were prepared by stoichiometric milling and relevant physical properties are collected in Table 3 [20]. 

Solid tertiary amines and imines may be quantitatively alkylated by gas-solid and solid-solid techniques. Methylation of quinuclidine (176) to give the methoiodide 177 is achieved waste-free by exposure of 176 to a stoichiometric amount of methyl iodide vapor (Scheme 23). Difficulties with the disintegration of the crystals of 177 from those of 176 (reaction step 3) are overcome by ultrasound treatment from a cleaning bath at 20 °C [22]. Numerous applications of this technique to tertiary amines can be envisaged. However, solid Troeger s base (with interlocked layers, i.e., no possibility for molecular migrations) is not alkylated by methyl iodide vapor unless an excess of the vapor is applied to induce intermediate (partial) liquefying of the solid [22]. 

The feedstock is sprayed onto a fluidized bed of hot coke particles which is agitated by the gaseous products rising through the bed in the reactor. The fluidized solids technique permits the use of higher temperatures (than delayed coking) but without the usual overabundance of coke formation because of the shorter contact times with the result that higher yields of liquid products are produced. 

Most NMR measurements are carried out in solution, where rapid molecular motion removes the effects of chemical shift anisotropy and (generally) produces sharp lines. For the study of solids, techniques are used which combine rapid spinning about the magic angle axis with special pulses, which remove much of the anisotropy and produce pseudo-solution spectra. 

Although the fluid-solids technique was originally developed for use in catalytic cracking, it is also being applied to other processes (156). 

Fluid coking is a continuous process that employs the fluidized solids technique for the conversion of heavy low-grade feedstocks to lighter, more valuable products. The feedstocks charged to a fluid coker may be any type of resid or residuum where the carbon residue falls into the range 5-50 wt% or those materials having an API gravity less than 20. 

J. Peuravuori, N. Paaso, K. Pihlaja (1999). Characterization of lake-aquatic humic matter isolated with two different sorbing solid techniques pyrolysis electron impact mass spectrometry. Anal. Chim. Acta, 391, 331-344. 

In contrast to delayed coking, fluid coking is a continuous process which uses the fluidized solids technique to convert vacuum residue to more valuable products, and coke formed during this kind of coking is a byproduct of the process... 

Ion-exchange chromatography is a liquid-solid technique of column chromatography and comprises of an electrolyte solution as the mobile phase and an ion-exchanger as the staionary phase. 

Lehtonen, T., Peuravuori, J., and Pihlaja, K., Characterization of aquatic humic matter isolated from two different sorbing solid techniques tetramethyl ammonium hydroxide treatment and pyrolysis-gas chromatography/mass spctrometry. Anal. Chim. Acta, 424, 91-103, 2000. 

The most obvious sources of error in analyses are related to insufficient extraction, low and irreproducible recoveries, insufficient peak resolution in chromatography, and the transformation of mercury species that may lead to artifacts. In the case of solubilized samples such as fish and mussels, speciation analysis was generally successful. However, with solids, techniques to remove or solubilize MeHg are complicated to validate by using spiking or tracer approaches, as it is difficult to prove that complete extrac-tion/separation has been achieved. A classical example of this difficulty is speciation of MeHg in sediments and soils. The only feasible approach adopted in certification of MeHg is to use different analytical approaches - that is, various extraction/sep-aration schemes and detection methods... 

The development took only three years from the initial concept to the first commercial operation. This paper reviews the development of the Fluidized Solids Technique, which revolutionized petroleum refining and created a new field of chemical engineering. 

This discussion has focused on the basic developments leading to successful commercialization of the Fluidized Solids Technique however, many areas were important to success of the project and were pursued vigorously at the same time. Some of these are listed in Table 3. For example, the availability of special equipment had to be assured, including cyclones, slide valves and expansion joints. Also, metals and refractories had to be tested and methods of fabrication developed. A large supply of catalyst was needed. Fortunately, the natural clay type catalyst used initially was readily available, having been used for clay treating of lubricating oils, etc. It was soon found that a synthetic silica-alumina catalyst was much better, with the result that a whole new industry was started to supply it. Twenty years later the silica alumina catalyst was displaced by the more active zeolites. 

Catalytic cracking to make high-octane gasoline was the first application of the new Fluidized Solids technique, and provided the impetus for commercial development. Since then, a great many other applications have been explored and many of them carried through to commercial use. Table 4 lists some of these. Fluid coking, as one example, fluidizes particles that are coated with a sticky liquid. 

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