Chemical neutralization

The sulfides are chemically neutral they can have a linear or ring structure. For molecules of equal carbon number, their boiling points are higher than those of mercaptans they constitute the majority of sulfur containing hydrocarbons in the middie distillates (kerosene and gas oil). 

Chemical Neutralization. Spray-type air washers are used extensively for removal or neutrali2ation of noxious components from large volumes of air, particularly exhaust air streams. Appropriate reagents are sprayed into the washer to purify the air by neutrali2ation, eg, sodium hydroxide solution is used if the air contains acidic gases. The solution must be continuously reconcentrated and any precipitated salts removed. The contact efficiency of such washers is high, and the simple constmction provides easy maintenance and constant efficiency (see AiRPOLLUTlON CONTROL METHODS). 

If decontamination caimot be left to natural processes, chemical neutralizers or means of physical removal must be employed. In general, the neutralizers are of two types chlorine-based oxidants or strong bases. Some neutralizers have been especially developed for the decontamination of chemical agents. 

Neutralization Acidic or basic wastewaters must be neutrahzed prior to discharge. If an industry produces both acidic and basic wastes, these wastes may be mixed together at the proper rates to obtain neutral pH levels. Equahzation basins can be used as neutralization basins. When separate chemical neutralization is required, sodium hydroxide is the easiest base material to handle in a hquid form and can be used at various concentrations for in-line neutralization with a minimum of equipment. Yet, lime remains the most widely used base for acid neutr zation. Limestone is used when reaction rates are slow and considerable time is available for reaction. Siilfuric acid is the primary acid used to neutralize high-pH wastewaters unless calcium smfate might be precipitated as a resmt of the neutralization reaction. Hydrochloric acid can be used for neutrahzation of basic wastes if sulfuric acid is not acceptable. For very weak basic waste-waters carbon dioxide can be adequate for neutralization. 

Larson, T. V., Frank, R., Covert, D..S., Efolub, D., and Morgan, M.S. (1982). Measurements of respiratory ammonia and chemical neutralization of inhaled sulfuric acid aerosol in anesthetized dogs. Am. Rev. Respir. Dis. 125, 502-506. 

Chemical neutralization Chemical reaction that converts acids or bases to... 

The reaction takes place at low temperature (40-60 °C), without any solvent, in two (or more, up to four) well-mixed reactors in series. The pressure is sufficient to maintain the reactants in the liquid phase (no gas phase). Mixing and heat removal are ensured by an external circulation loop. The two components of the catalytic system are injected separately into this reaction loop with precise flow control. The residence time could be between 5 and 10 hours. At the output of the reaction section, the effluent containing the catalyst is chemically neutralized and the catalyst residue is separated from the products by aqueous washing. The catalyst components are not recycled. Unconverted olefin and inert hydrocarbons are separated from the octenes by distillation columns. The catalytic system is sensitive to impurities that can coordinate strongly to the nickel metal center or can react with the alkylaluminium derivative (polyunsaturated hydrocarbons and polar compounds such as water). 

Aprotic solvents include those substances which may be considered to be chemically neutral and virtually unreactive under the conditions employed. Carbon tetrachloride and benzene come in this group, they possess low dielectric constants, do not cause ionisation in solutes and do not undergo reactions with acids and bases. Aprotic solvents are frequently used to dilute reaction mixtures while taking no part in the overall process. 

The sensitivity of a region to acidic deposition is related primarily to its capacity to reduce or chemically neutralize acidity. If there is an ability to quickly and effectively return conditions to nearly normal, the effects of the deposition will be minimized and the ecosystem is not considered to be sensitive. However, if there is little or no capacity to reduce the acidity, the ecosystem is highly sensitive and severe damage can occur if the acidic deposition is significant. 

Distillates (petroleum), chemically neutralized heavy paraffinic... 

T0187 Covenant Environmental Technologies, Inc., Mobile Retort Unit T0191 Cunningham-Davis Environmental (CDE Resources, Inc.), ID-20 Chemical Neutralization Process... 

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