Sulfuric acid operation, effects

The main justification for diesel fuel desulfurization is related to particulate emissions which are subject to very strict rules. Part of the sulfur is transformed first into SO3, then into hydrated sulfuric acid on the filter designed to collect the particulates. Figure 5.21 gives an estimate of the variation of the particulate weights as a function of sulfur content of diesel fuel for heavy vehicles. The effect is greater when the test cycle contains more high temperature operating phases which favor the transformation of SO2 to SO3. This is particularly noticeable in the standard cycle used in Europe (ECE R49). 

The aim of this work is to study the incorporation of cadmium and phosphate in the three calcium sulfate modifications. The uptake of other metal ions in AH will also be described. Kinetic effects of operating conditions such as the residence time, sulfuric acid and phosphate concentration upon the phosphate and cadmium uptake has been investigated. In addition the influence of a growth retarding impurity, AIF3, on the cadmium and phosphate uptake will be given. 

Smelter Acid. If acid is produced involuntarily, as in a smelter operation, it is possible to estimate the cost of acid production in the same manner as that for an elemental sulfur acid plant. To the smelter, however, acid output is simply a mandated concomitant of the process required to produce the metal. Depending on the location of the smelter, the sources of demand, the size of the market, and competition from other producers, the acid sale price may or may not be sufficiently high even to yield a positive net-back, much less a desired rate of return on investment for the acid portion of the operation. This situation does not necessarily lead to closure. Positive or negative, the effect should be registered only in the overall profitability of the entire smelter operation. 

Pour 50 cc. of concentrated sulfuric acid slowly into about 1 liter of water in an evaporating dish and add 50 g. of iron nails or turnings. When the action becomes slow heat the dish until the acid is practically all neutralized, as indicated by the fact that evolution of hydrogen ceases. Filter from the undissolved iron, carbon, silicon, and other residues, using a folded filter, and evaporate to crystallization. If the solution oxidizes appreciably in the operation additional iron and acid must be added to effect reduction. Oxidation will be indicated by a change in color from bottle green to a yellowish shade of green, or by the formation of a rusty precipitate. 

Incidents of several different types have arisen from reactions involving neutralisation of an acid with a base where the exotherm (57.3 kJ/equivalent for strong acid—strong base reactions) has not occurred smoothly over an extended period, but has been sudden in effect for various reasons. Individually indexed neutralisation incidents are f Formaldehyde, Magnesium carbonate hydroxide, 0415 Potassium hydroxide, Acids, 4422 Sodium carbonate, 0549 Sulfuric acid, 4-Methylpyridine, 4473 Sulfuric acid, Diethylamine, 4473 2,4,6-Trichloro-l,3,5-triazine, 2-Ethoxyethanol, 1035 See related UNIT process or unit operation incidents... 

The effects of the operational conditions in the hydrolysates and solid composition were compared using CS in the range of 1.39-3.06. Sulfuric acid concentration and reaction temperature were kept constant for all runs. The severity was varied by setting the isothermal period from 2 to 240 min. 

The fluorination of quinoline was performed in a microstructured reactor operated in the annular-flow regime, which contained one microchannel with two consecutive feeds for gas and liquid [311,312]. The role of the solvent was large. The reaction was totally unselective in acetonitrile and gave only tarlike products. With formic acid, a mixture of mono- and polyfluorinated products besides tar was formed. No tar formation was observed with concentrated sulfuric acid as solvent at 0-5 °C. In this way, a high selectivity of about 91% at medium conversion was achieved. Substitution was effective only in the electron-rich benzenoid core and not in the electron-poor pyridine-type core. The reactivity at the various positions in the quinoline molecule is 5 > 8 > 6 and thus driven by the vicinity to the heteroatom nitrogen that corresponds to the electrophilic reactivity known from proton/deuterium exchange studies in strong acid media. 

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