Water-stripping

Sour water is to be routed to sour water stripping facilities. 

Tray efficiency is calculated as previously demonstrated and will not be repeated, except that normally stripping tray efficiencies run lower than rectification efficiencies. For ammonia-water stripping such as this example most over-all efficiencies run 50-60%. 

Random and structured packings are susceptible to surface fouling due to process conditions and/or the presence of oxygen as may be related to bacterial growth. Some systems will precipitate solids or crystals from solution usually due to the temperature and concentration effects. Bravo [135] discusses air-water stripping and illus-... 

The moles X/moles P in average plankton is given by a, and b is the surface water concentration in phosphorus free water (water stripped of nutrients). In the case of P itself the surface ocean concentration is close to zero, while the deep Pacific has a concentration of 2.5 pM. For N, the N/P ratio of plankton is 16 and the surface water concentration is 0 pM. The predicted deep sea nitrate is 40 pM. The ratio of (deep)/(surface) is greater than 10. For calcium the Ca/P of... 

The conference was subdivided into four sessions, and chapters within this text are arranged according to these categories. Papers included in the first section (Thermodynamics of Electrolytes for Pollution Control) provide the reader with insights into the practical aspects of pollution control, as well as an overall appreciation of applied electrolyte phase equilibria. Other chapters include detailed descriptions of thermodynamic models that recently have been developed to describe important industrial pollution control processes with emphasis on acid gas absorption/sour water stripping and flue gas desulfurization. 

A number of models have been developed to describe the chemistry occurring in sour-water stripping and absorption. 

Wennersten found that the extractant system tri- -butylphosphate (TBP) in Shellsol A diluent was temperature dependent with extraction decreasing with increasing temperature. Therefore, extraction from the broth at room temperature (22°C) and water stripping at 60°C provided an efficient process (Fig. 10.9). The extraction with long-chain amines was hampered by the formation of emulsions and thus poor separation. Emulsion formation depended on the diluent with hydrocarbons, e.g., Alamine 336/Shellsol A, given the best separation. 

The first step in good pretreatment practice is the segregation of major wastewater streams. This frequently simplifies waste treating problems as well as reducing treatment facility costs. Treatment at the source is also helpful in recovering byproducts that otherwise would not be economically recovered from combined wastes downstream [35]. Four major pretreatment processes that are applicable to individual process effluents or groups of effluents within a refinery are sour water stripping, spent caustics treatment, ballast water separation, and slop oil recovery. These are discussed below. 

Water Strip sample in sparger with helinm adsorb efflnent gas to adsorption tnbe thermally desorb to GC GC/FID/MS 10 g/L 89.7-95.7 Bianchi et al. 1991... 

Enzyme flexibility is greater in solvents with high polarity because of weaker electrostatic interactions in these solvents [54, 104, 105]. The loss in enzyme activity seen in the NMR study described above may be attributed to the water stripping model as water is stripped from the enzyme, locations in and on the enzyme previously inaccessible to the solvent may become accessible, thus permitting increased solvent-enzyme interactions [103]. As a result, enzyme structure may be disrupted (e.g., partially denatured), and catalytic activity is decreased. The partially denatured enzyme appears to exhibit greater flexibility as solvent polarity increases [106, 107]. 

Two resins were tested for the removal of succinic acid from simulated medium on a packed column of sorbent to simulate an actual process on a small scale. It is important to test the sorption with medium, because salts and other nutrients can interfere with the sorption. Table 4 presents the results for XUS 40285 MWA-1 was comparable. This indicates that either sorbent can remove succinic acid efficiently from the fermentation broth without direct loss of product. Both columns were then stripped or regenerated with hot water. Stripping with hot water recovered 70-80% of the succinic acid from the XUS 40285 resin whereas less (50-60%) was recovered from the MWA-1. The XUS 40285 column was stripped with 2 column volumes of hot water with eluent concentrations up to 49 g / L. Succinic acid was concentrated on average to 40 g/L in the XUS resin by this operation and to 30 g/L by the MWA-1. The 10-fold concentration factor bodes well for the use of sorbents to purify the fermentation broth. 

First, the effects of gas and liquid flows, co-current versus countercurrent operation, pressure and temperature were checked. As expected, based on the influence of these parameters on the vapor pressure or the vapor-liquid equilibrium (VLE), the fraction of water stripped by the nitrogen increases with increasing gas flows, decreasing liquid flows, lower pressures and higher temperatures. Countercurrent operation is more efficient than co-current operation, because the liquid phase at the inlet was already enriched with the compound which was to be separated. 

In order to understand the maxima and the minimum of the instantaneous selectivity Smstr it is useful to plot the predictions of the kinetic model as represented by the two rate Equations (1) and (2). In Fig. 8.31, the S m( expected from the kinetics is plotted depending on the fraction of water stripped from the liquid. All these curves start at around 75 %, increase to near-unity, and then show a sharp drop at high inlet conversion levels. Depending on the fraction of water stripped, the slope of the initial increase and onset of the final drop of Smst differ. 

Sour-Water System Improvements Sour water is the most likely source of Refinery odor problems. Follow-up on projects previously identified by Linnhoff-March engineering to reduce sour water production, and improve sour water stripping. 

In addition, the following equation has been developed for the calculation of the number of transfer units (NTU) for an air-water stripping system and is based on the stripping factor, R, and the inlet/outlet concentrations ... 

Overall, protein activity is affected by four major factors a) the ground state, thermodynamic stabilization of the protein, b) active site flexibility response to solvent polarity and adsorbed water content, c) the impact of water stripping from the protein on the active conformation and d) direct solvent induced perturbation of the protein (Dordick, 1992). 

Jeong, J. C. and Lee, S. B., Enzymatic esterification reaction in organic media with continuous water stripping effect of water content on reactor performance and enzyme agglomeration, Biotechnol. Tech., 11, 853-858, 1997. 

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