Abatement methods

Plant layout and noise suppression material are two general noise abatement methods. Plant layout does not affect noise levels at any given point however, noise can be abated by screening off a section of the plant. An example of this is to orient cooling towers with their closed faces toward the critical location. This method must also consider wind direction to balance air draft. Tankage can be located to act as a noise screen. 

Emission abatement methods covered are suitable for the emission control of volatile organic compounds (VOCs). The VOCs include organic compounds existing in the gaseous phase in air at 293.15 K. However, or ganic compounds, which are not regarded as VOCs, can be treated by the methods covered in this section. 

The first task in selecting an abatement method is the preparation of an emission inventory. The inventory is the basis of planning and the selection of options. By the preparation of an inventory, all emission sources requiring treatment can be determined and recorded. The emission inventory... 

Concentration and Composition The average concentration of organic compounds in a waste gas determines the applicability of the abatement method. Recovery methods usually require high inlet concentrations. They may need a concentrator prior to actual treatment, which increases the investment cost. 

When a mixture of compounds is to be treated, more limitations may be placed upon the selection of a suitable abatement method. There may be several compounds in the waste gas, some being unsuitable to one method, while others are unsuitable to another method. In such cases, thermal incineration may be the best solution. When recovering mixtures, additional separation equipment may be needed for recycling the reclaimed compounds. 

Both these methods relate to the required removal efficiencies of the pollution control equipment. All abatement methods achieve high removal efficiencies when used in the correct applications (Fig. 13.19). The highest efficiency (with limitations) is in most cases achieved with incineration. When removal efficiencies of 99% or greater are required, incineration is usually recommended. ... 

In its NEP, OSHA points out that for workplaces not covered by 1910.272, but where combustible dust hazards exist within dust control systems or other containers, citations under section 5(a)(1) of the OSH Act (the General Duty Clause) may generally be issued for deflagration (fire) or explosion hazards. National Fire Protection Association (NFPA) standards should be consulted to obtain evidence of hazard recognition and feasible abatement methods. Other standards are applicable to the combustible dust hazard. For example, if the workplace has a Class II location, then citations under 29 CFR 1910.307 may be issued to those employers having electrical equipment not meeting the standard s requirements. 

Increasingly stringent environmental regulations imposed on both the military and civilian sectors has created a growing demand for alternative abatement methods for a variety of hazardous compounds. One alternative, the nonthermal plasma, shows promise of providing an efficient means for the destraction of dilute concentrations of hazardous air pollutants. Promising results have been obtained for toluene, methylene chloride, and dichlorodifluoromethane in air at concentrations of a few hundred parts per million. The device has been operated at voltages up to 30 kV, pulse repetition rates up to 1.4 kHz, and flow rates up to 60 1/min (Korzekwa et al., 1998). 

The development of pollution abatement methods is directed towards new techniques and new ways of upgrading the quality of life. 

Discuss various noise abatement methods and techniques. 

The primary collection system, where the bulk of the cell fluoride loss is captured, may simply discharge to a tall stack [24]. This aids in dispersal, which may be sufficient for a small smelter. But it neither decreases mass discharge rates nor allows recovery of fluoride for reuse. In some cases, a stack has been found to cost more to operate than abatement methods, which employ fluoride capture. 

As previously established, the catalytic oxidation of volatile organics to carbon dioxide and water offers significant advantages over all other current VOC abatement methods, as it enables complete destruction at relatively low temperatures with high volumetric throughput. A variety of parameters, other than the nature of the catalyst, influence this process. These include operational temperature, pre-heating of the system, space velocity, the oxidant used for the combustion, the nature and concentration of VOC(s) in the feed gas, and the deactivation of the catalyst. 

Abatement Method Minimum Concentration jppm Maximum Concentration /ppm... 

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