Case Study — Site Considerations

Nitric acid and the nitrogen oxide gases present in the process are highly toxic. It is imperative that the choice of site selection and plant layout reflects the potential hazard from both of these sources. 

The nitric acid plant will be part of a chemical plant complex that will include an ammonia plant, a nitric acid plant and an ammonium nitrate plant. Consideration is given to the needs of all three of these plants in the site selection procedure. 

The site chosen for the nitric acid plant, as a part of the larger chemical plant, is a 10 hectare plot in the Bunbury district of Western Australia. The site is located between the port handling facilities (for alumina) belonging to Alcoa of Australia Ltd, and Leschenault Road. The site runs parallel to the Preston River and is less than 1 km from the main port area. It features easy port access, adjacent rail facilities, and an abundance of river water (for process cooling purposes). 

The layout suggested for the chemical plant complex includes a central control room to operate all three plants. Administration, laboratory, and workshop areas are also common. The nitric acid plant is small, occupying less than 1 hectare. There is space on the 1 hectare plot for inclusion of a second parallel process train for possible future expansion. 

Normal operation should be well within the environmental regulation limits set by the EPA. Liquid waste is virtually non-existent and can be sent to the normal sewerage drains. Any acid spills should be diluted. Tail-gas emissions are thought to be less than 1000 ppm of nitrogen oxides (about half the current EPA limit). Should tail-gas emissions exceed this figure, then a catalytic combustor would be necessary to reduce nitrogen oxide levels to below 400 ppm. 

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The two methods gave considerably different results when applied to the liquid hydrocarbon storage site case study. The TNT-equivalency method systematically... 

Epoxy resins and curing agents usually contain more than one reaction site per molecule, and the process of curing to form a three-dimensional network results from multiple reactions between epoxide molecules and curing agent. The specific reactions of the various reactants with epoxide groups have, in many cases, been studied in considerable detail and have been extensively reviewed elsewhere (2). 

For all cases studied, the Y zeolites are considerably more acidic than the X zeolites. This may be unexpected since there are more ion exchangeable cations in X zeolites and consequently more potential acid sites. It is possible that the weaker electrostatic fields in X zeolites do not result in the production of the maximum number of hydroxyl groups. In fact, for Ca and Mg, the Bronsted acidity increased linearly with decreasing aluminum content of the zeolite (69). Quinoline chemisorption also has been used. However, the results indicate that only Lewis acid sites are detected (10). 

In our case study, the two-sink model fitted most experimental data very efficiently. However, it is not supposed to provide a complete physical description of the real adsorption process(es). Increasing the number of regression parameters in any equation improves its adherence to the data. However, the model is supposed to be a better approximation to the more complex reality. This reality may include adsorption sites with a distribution of adsorption enthalpies instead of simply two distinct values, and may also include diffusion processes within the sorbing material. A further development of the two-sink model could take into consideration the transfer of molecules from the faster (more superficial) to the slower (deeper) sink sites. The model in its present form can be used to estimate four unknown parameters, i.e. the adsorption and desorption rate constants for each of the two sinks. 

The noncovalent interactions involved in the stabilization of the enzyme-substrate complex are the same as those involved in the stabilization of the protein stmcture. Many interactions are involved, but the strength of the interaction between enzyme and substrate varies considerably, although the equilibrium dissociation constants generally fall into the micromolar and millimolar range. In aU cases studied so far, very specific binding sites for substrates are found on enzymes these are called the active sites. 

A slope chosen for the case study is located in Southeast Washington D. C., and a plan view of the slope site is shown in Figure 2. There exist a parking lot, a storm water collection system, water and sewer systems and pavements within the area of the slope located. The ground movement within the slope had caused extensive damages to the facilities and properties. Moreover, the slope failure has caused considerable inconvenience as well as safety concerns to the publics. In order to stabilize the distressed slope, the remedial solutions to the slope are presented on the basis of the probabilistic method and the current conditions of the... 

Because oceans have continued to provide sites for energy development and utilization, mega-scale floaters have been playing a critical role in energy sectors. Without doubt, their role will continue to increase in the future. Thus, many technologies have been developed to maintain the position of offshore installation. In this case study, PGS, a position keeping solution for mega-scale floaters, was taken into consideration. 

Busan New Port in the Republic of Korea is selected as the target site for this case study. Busan Port Authority (BPA) has a plan to make Busan New Port an international logistics center port of Northeast Asia. In accordance with the technical report (J.W. Lee et al. 2009), many offshore installations will be taken into consideration for the shipping infrastructure near the Busan New Port. 

Terra-Vac, Inc., developed the In-Situ Vacuum Extraction process, which removes volatile organic constituents (VOCs) from the unsaturated zone of soils through extraction wells. The extracted gases and water proceed to a vapor-liquid separator and an emission control system. The process has been employed at over 60 sites. Four case studies, including three Superfund sites, have been documented. The process represents a viable technology to fully remediate sites contaminated with volatile organics. Considerations for use include contaminent volatility, site-specific cleanup level, and soil properties. The process works well with most soil types. The air-filled porosity of a soil is an important criterion to indicate whether vacuum extraction will work. Soils with low permeability but with... 

Whatever the case, the ability to irrigate test plots is an important consideration during field site selection. Sprinkler irrigation is preferred. Flood and furrow irrigation should be avoided since they may disturb surface residues, resulting in uneven residue distribution and/or inadvertent agrochemical loss from the study plots. Recommended irrigation practices are discussed in more detail in Section 3.3.8. 

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