Tubular precipitators

A development of interest to the chemical industiy is the tubular precipitator of reinforced-plastic construction (Wanner, Gas Cleaning Plant after T1O2 Rotary Kilns, technical bulletin, Lurgi Corp., Frankfurt, Germany, 1971). Tubes made of polyvinyl chloride plastic are reinforced on the outside with polyester-fiber glass. The use of modern economical materials of construction to replace high-maintenance materials such as lead has been long awaited for corrosive applications. 

Suprofen-induced AKI is characterized by acute flank and/or abdominal pain. In series of 16 patients. Hart et al. [114] described that the mean peak serum creatinine was 3.6 mg/dl (range 2 to 8 mg/dl), which returned to normal limits at follow-up. Suprofen is know to have uricosuric activity leading Hart and colleagues [114] to suggest that this renal syndrome may have resulted from ureteral or tubular precipitation of uric acid. 

Fig. 4 Relative field strength between the electrodes of a tubular precipitator arrangement. (View this art in color at WWW. dekker. com.)...

Tubular Precipitator. This type of continuous operation may be employed to reduce polydispersity of precipitates (Raphael et al. 1997 Raphael and Rohani 1999). The tubular precipitator may operate either under the turbulent flow or laminar flow regime. The reactants are added into the inlet section equipped with static mixers and may also enter as a multi-port feed along the length of the tubular precipitator. If the reactant feeding streams are too concentrated or if too excessive formation of precipitate occurs in the inlet section of the precipitator, a third stream of solvent is also fed to dilute the flowing suspension. The latter may contain a protective colloid or surfactant that prevent agglomeration of precipitate. 

Finally, we touch upon selected practical aspects of typical precipitation operations, using continuous MSMPR and tubular precipitators, and a semi-batch precipitator as illustrative examples. 

G. Renal failure. Examples of dmgs and toxins causing renal failure are listed in Table I-28. Renal failure may be caused by a direct nephrotoxic action of the poison or acute massive tubular precipitation of myoglobin (rhabdomyolysis), hemoglobin (hemolysis), or calcium oxalate crystals (ethylene glycol) or it may be secondary to shock caused by blood or fluid loss or cardiovascular collapse. 

Types of Precipitators. Studies on precipitation of oilseeds proteins have been reported by several workers using various types of precipitators. Batch precipitators have been used by many (2-7). Others (S-11) used mixed suspension mixed product removal (MSMPR) precipitators. Tubular precipitators have also been used (2,12,13). 

In the mixed suspension mixed product removal precipitators mixing of newly formed particles with old ones results in precipitates with a wide particle size distribution. A tubular precipitator operating in the turbulent flow regime produces a narrow PSD and in the laminar flow regime a wide PSD (13). A batch precipitator... 

Figure 3. The effect of precipitation time on the mean particles size (sunflower protein) for the batch, MSMPR, and tubular precipitators = batch precipitator (600 rpm) + = batch precipitator (900) = MSMPRP (600 ipm) A = tubular precipitator flow Re = 800 = tubular precipitator flow Re = 5,000. (A, B) = Protein feed concentration =11.8 kg/m (C,D) = Protein feed concentration = 2.9kg/ml...

Figures 6 and 7 present the solids yield for canola and sunflower proteins during isoelectric precipitations, respectively. Sunflower protein yields from the flow-type precipitators increased with increases in mean residence times. This means that slower processes of particle growth by aggregation and diffusion follow an initial rapid nucleation process. About two minutes are required before the final yield is reached according to the results obtained from the tubular precipitator operating in the laminar flow regime and the batch precipitator. For canola proteins, mns in an MSMPR precipitator showed little changes in the yield with the mean residence time. This is because the mean residence times were longer (between 1.5 and 7.5 min) allowing the reaction to go to completion.

Precipitation in a Tubular Precipitator Operating in the Dispersion Regime. 

The semi-empirical model used for an MSMPR and the dispersion model for the tubular precipitator proved to be capable of deterniining the kinetic parameters (nucleation rate, aggregation rate, and growth rate) from the experimental data. 

Makki, R., Roszol, L., Pagano, J., Steinbock, O. Tubular precipitation struemres materials synthesis under nonequilibrium conditions. Phil. Trans. R. Soc. A 370, 2848 (2012)... 

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