Regulatory control stacks

Regulatory control is governmental imposition of limits on emission from sources. In addition to quantitative limits on emissions from chimneys, vents, and stacks, regulations may limit the quantity or quality of fuel or raw material permitted to be used the design or size of the equipment or process in which it may be used the height of chimneys, vents, or stacks the location of sites from which emissions are or are not permitted or the times when emissions are or are not permitted. Regulations usually also specify acceptable methods of test or measurement. 

Perry and Lee [28,29] offer an enhancement of QPA, based upon use of dual heat flux sensors and additional thermocouples in autoclave curing. This enhancement entails determining heat transfer properties during the cure, then using these properties in conjunction with PID regulatory control of autoclave temperature. Using the additional sensors, Perry and Lee employ an on-line Damkohler number in lieu of the second time-derivative of temperature to avoid exothermic thermal runaway within the prepreg stack thermoset resin. The Damkohler number is defined as ... 

The State has listed seven sites in the state for possible Superfund action At one, several thousand drums of waste were stacked above ground, and then abandoned. Another represents a case of good intentions gone bad a commercial waste site that lacked tight regulatory controls to set its operating conditions, and consequently got into trouble. Another started out as a municipal solid waste site, and somehow ended up as an uncontrolled dump for hazardous wastes. Still another was an old waste oil recovery plant that was operated very poorly, in a poor site area. 

Cement plants in the United States are now carehiUy monitored for compliance with Environmental Protection Agency (EPA) standards for emissions of particulates, SO, NO, and hydrocarbons. AH plants incorporate particulate collection devices such as baghouses and electrostatic precipitators (see Air POLLUTION CONTROL methods). The particulates removed from stack emissions are called cement kiln dust (CKD). It has been shown that CKD is characterized by low concentrations of metals which leach from the CKD at levels far below regulatory limits (63,64). Environmental issues continue to be of concern as the use of waste fuel in cement kilns becomes more widespread. 

The first step in designing a stack for air pollution control purposes is to determine exactly what regulatory constraints and requirements exist at the particular site. These constraints and requirements may be so severe that alternative means of air pollution control may have to be sought. In any case, the regulations specify a performance standard to which the stack must be designed, and against which the design can be evaluated. 

There is a need today to quantify the effects of aerosol sources on ambient particulate matter loadings. Identifying the major sources of ambient particulate matter loadings was a fairly simple process when values exceeded 500 /ig/m and stack emissions were plainly visible. Control of these emitters was forthcoming and effective. At levels of 150 to 200 fxg/w , the use of annual emission inventories focused further regulatory efforts on major sources which have resulted in more successful reductions. Presently, at levels around 75-100 /ig/m, the uncertainties involved in these assessments of source contributions are greater than the contributions themselves. 

The authors are grateful to colleagues at Tata Steel, Mr Simon Johnston, Mr Richard Earl and Mr Pete Smith for collecting the stack emission samples used in this study and providing expert advice in XRF and carbon-sulphur analysis. This work has benefitted from collaboration with the regulatory authorities who have confirmed that best practicable means were used to measure and control sinter plant stack emissions. 

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