Primary conversions

The converted mash is pumped to a clean sterilised fermentor and the yeast inoculum is added. The set temperature range for whiskey fermentation of 72 hours is usually 17—21°C. At the beginning, the mash converted composition is approximately 80% sugars, mainly maltose and some (<1%) dextrose (primary conversion). The pH is adjusted to reduce initial bacterial growth. Grain neutral spidts are usually set at 27—29°C to expedite fermentation. Temperatures above 35°C inhibit yeast reproduction and promote rapid bacterial growth. Above 40°C actual yeast kill occurs. 

Fluid catalytic cracking (FCC) continues to play a key role in an integrated refinery as the primary conversion process. For many refiners, the cat cracker is the key to profitability in that the successful operation of the unit determines whether or not the refiner can remain competitive in today s market. 

Two principle approaches from thiopyrylium salts to thiopyrans accompanied by C-substitution have been found, e.g., the one-step additions of C-nucleophiles or the two-step procedures involving primary conversions of the salts to nucleophilic intermediates followed by attacks with appropriate electrophiles. 

In order to compete with fossil fuels, biofuels must become available in a variety of guises to meet the needs of our energy-hungry society. In order to meet these needs a number of primary conversion processes have been developed as summarized in Figure 6.3. 

The influence of coal structure on primary conversions and oil yields in thermolytic extraction with different H onor and non-H-donor solvents and in dry catalytic hydrogenation has been investigated. 

The mobile phase and the nature of H-donor and non-donor solvents all have a profound influence on primary conversions. In contrast, distillate or oil yields often correlate with parameters reflecting the aliphaticity of coals (H/C ratio -decreasing vitrinite reflectance - CHj content - Z), better correlations being achieved for low-rank coals if yields are expressed on a free" basis... 

In this paper, a number of low-severity liquefaction regimes are considered. The influence of different H-donor and non-donor solvents on primary conversions without a hydrogen overpressure is discussed in the light of other recent work (10-131. Also, it is demonstrated that oil yields broadly increase with decreasing coal rank in both H-donor extraction and dry catalytic hydrogenation provided that retrogressive reactions are avoided in the initial stages of coal dissolution. 

Primary Conversions and Influence of Mobile Phase Yields for the various H-donor and non-donor solvent extractions of Linby coal at 400% are summarised in Table III the conversions for the THF-extracted coal include the extracted material. Surprisingly, pre-extraction with THF significantly increases primary conversions in the polynuclear aromatic compounds (PACs) investigated. These findings appear to be contrary to those of other liquefaction (16) and pyrolysis (17) studies where prior removal of chloroform-extractable material significantly reduced conversions. However, Rincon and Cruz (18) have reported recently that pre-swelling coals in THF increases conversions for both anthracene oil and tetralin. The fact that Point of Ayr (87% dmmf C) coal yielded over 80% pyridine-solubles in pyrene (C.E. Snape, unpublished data) without pre-extraction is consistent with the earlier results of Qarke et al (19) for anthracene oil extraction where UK coals... 

The sulfur plant will also be impacted by minor constituents in the raw gas. Depending upon the primary conversion system utilized, the raw gas may contain sugnificant quantities of cyanides, ammonia, oils, and light hydrocarbons. Sulfur may be present in the forms of carbonyl sulfide, carbon disulfide, mer-captans, thiophenes, or other species. Design engineers should be aware of these species and their variability, in order to provide sufficient protection in the overall system. 

The importance of the determination of sulphuric acid and sulphates lies very largely in the fact that sulphur in various forms of combination, and also free sulphur, is frequently determined quantitatively by primary conversion into sulphuric acid or sulphate, followed by actual estimation in the latter form. For example, a convenient volumetric process applicable to the Carius method for determining sulphur in organic compounds is to neutralise the solution of sulphuric acid after removal of the excess of nitric acid by evaporation, and then add silver nitrate, by which the sulphate is converted into silver sulphate. This is separated from the excess of silver nitrate by means of its insolubility in alcohol, and is then estimated by dissolving in dilute nitric acid and titrating the silver with standard thiocyanate solution.3... 

Currently, delayed coking and fluid coking are the processes of choice for conversion of Athabasca bitumen to liquid products. Both processes are termed the primary conversion processes for the tar sand plants in Ft. McMurray, Canada. The unstable liquid product streams are hydrotreated before recombining to the synthetic crude oil. 

Although the process may not be the means by which direct conversion of the bitumen to a synthetic crude oil would be achieved it does nevertheless offer an attractive means of bitumen conversion. Indeed, the process would play the part of the primary conversion process from which liquid products would accrue—these products would then pass to a secondary upgrading (hydrotreating) process to yield a synthetic crude oil. 

It was also found that 2,6-dichlorobenzamide was the principal labeled metabolite. Now there are several possible routes for the hydrolysis of the benzoylphenyl ureas, as is illustrated in Figure 2, where route A would lead to ortho-substituted benzoic acids and jD-chloro-phenyl urea while routes 2 and 3 would both result in ortho-substituted benzamides and p-Cl-aniline as the primary conversion products. Evidently routes 2 or 3 were the preferred ones in the case of PH 6O-38 with X = Cl (28). 

Mechanistic details of the primary conversion to form the bicyclo[5.1.0]octane skeleton are available. " ... 

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