Treating processes acid

Gas turbine fuels can contain natural surfactants if the cmde fraction is high in organic acids, eg, naphthenic (cycloparaffinic) acids of 200—400 mol wt. These acids readily form salts that are water-soluble and surface-active. Older treating processes for sulfur removal can leave sulfonate residues which are even more powerful surfactants. Refineries have installed processes for surfactant removal. Clay beds to adsorb these trace materials are widely used, and salt towers to reduce water levels also remove water-soluble surfactants. In the field, clay filters designed as cartridges mounted in vertical vessels are also used extensively to remove surfactants picked up in fuel pipelines, in contaminated tankers, or in barges. 

A bleed from the scmbbing system is sent to a sour slurry stripper. The water is then clarified and can be recycled to minimize the volume of effluent to be biotreated and discharged or evaporated. The acid gas from the acid gas removal system and from the sour slurry stripper is fed to a Claus plant, where salable elemental sulfur (qv) is produced. For maximum sulfur recovery and minimal sulfur emissions, the Shell Claus off-gas treating process (SCOT) is used. 

Low acid gas partial pressures (product of system pressure and concentration of acid gases—HiS and CO2 in the feed) of roughly 50psi and below. Another way of looking at selection based upon acid gas concentration is Figure 1 in the previous section entitled Gas Treating Processes. 

Technology Description Neutralization is a process used to treat acids or alkalis (bases) in order to reduce their reactivity or corrosiveness. Neutralization can be an inexpensive treatment if waste alkali can be used to treat waste acid and vice versa. Typical neutralizing reagents include ... 

Although the conversion of an aldehyde or a ketone to its enol tautomer is not generally a preparative procedure, the reactions do have their preparative aspects. If a full mole of base per mole of ketone is used, the enolate ion (10) is formed and can be isolated (see, e.g., 10-105). When enol ethers or esters are hydrolyzed, the enols initially formed immediately tautomerize to the aldehydes or ketones. In addition, the overall processes (forward plus reverse reactions) are often used for equilibration purposes. When an optically active compound in which the chirality is due to an asymmetric carbon a to a carbonyl group (as in 11) is treated with acid or base, racemization results. If there is another asymmetric center in the molecule. 

The basic unit operations/processes required for treating the acid pickling wastewater are (a) neutralization with NaOH and/or lime to increase the pH and (b) physicochemical methods, such as chemical coagulation, precipitation, clarification (sedimentation or DAF), and filtration to remove BOD5, COD, and iron. 

S.A. Newman, Acid and Sour Gas Treating Processes , Gulf, Houston, 1985, Ch. 20. 

Benzyl Alcohols. Benzyl alcohols of nearly all kinds undergo reduction when treated with acid in the presence of organosilicon hydrides. The most obvious exception to this is the behavior of benzyl alcohol itself. It resists reduction by the action of trifluoroacetic acid and triethylsilane, even after extended reaction times.26 Reducing systems consisting of triethylsilane and sulfuric acid/acetic acid or p-toluenesullonic acid/acetic acid mixtures also fail to reduce benzyl alcohol to toluene.134 As previously mentioned, substitution of boron trifluoride for trifluoroacetic acid results in the formation of modest yields of toluene, but only when a very large excess of the silane is used in order to capture the benzyl cation intermediate and suppress Friedel-Crafts oligomerization processes.129,143... 

Corrosivity is that characteristic of chemicals that exhibits extremes of acidity or basicity or a tendency to corrode steel. Such chemicals, used in various refining (treating) processes, are acidic and are capable of corroding metal such as tanks, containers, drums, and barrels. On the other hand, reactivity is a violent chemical change (an explosive substance is an obvious example) that can result in pollution and/or harm to indigenous flora and fauna. Such wastes are unstable under ambient conditions insofar as they can create explosions, toxic fumes, gases, or vapors when mixed with water. 

Caustics are widely used in petroleum refineries. Typical uses are to neutralize and to extract acidic materials that may occur naturally in crude oil, acidic reaction products that may be produced by various chemical treating processes, and acidic materials formed during thermal and catalytic cracking such as H2S, phenolics, and organic acids. 

Cerium is obtained from its ores by chemical processing and separation. The process involves separation of cerium from other rare-eartb metals present in the ore. Tbe ore is crushed, ground, and treated with acid. Tbe extract solution is buffered to pH 3 and tbe element is precipitated selectively as Ce4+ salt. Cerium also may be separated from other metals by an ion-exchange process. 

This technology can treat both acidic and basic solutions. It has the ability to remove organics, inorganics, radionuclides, and heavy metals from contaminated aqueous streams and is capable of treating process wastes and mixed wastes as well. 

A more comprehensive study on the behavior of 5-acetylenic iodides in the presence of zinc was later reported21 and clearly revealed that when iodide 14 was treated with acid-washed zinc (pre-treated with Mel for activation and removal of traces of moisture) in a mixture of benzene and DMF, the acyclic organozinc iodide 21 and the cyclic vinyl iodide 22 were both produced. The amount of 22 increased significantly when the reaction mixture was sonicated rather than stirred or if a zinc-copper couple was used. The accumulation of compound 22 was consistent with its inability to be converted to an alkenyl organozinc species by reaction with metallic zinc under these conditions. However, no substantial cyclization of the open-chain organozinc 21 was observed. The formation of the five-membered ring compound 22 was attributed to a free-radical process... 

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