Control pressure drop

For fast-setthug slurries, ensuring conveyance is usually the key design issue while pressure drop is somewhat less important. For nonsettling slurries conveyance is not an issue, because the particles do not separate from the liquid. Here, viscous and rheological behavior, which control pressure drop, take on critical importance. 

The catalyst volume is the same on both sides. It is assumed that no diffusional rate limitation exists even in the larger pellets. That is, the chemical reaction rate is controlling. Pressure drop must be the same for both sides, so the flow has to be less over the smaller pellets to maintain the AP (L/dp)(u /2g) = constant. 

Presently a commercially available two stage vacuum system comprising a membrane (Pfeiffer MVP 006-4) and a turbo pump (Pfeiffer HiPace 10) in combination with a pressure sensor (Leybold Vacuum Ionivac ITR 90) establish a pressure of about 0.1 Pa in the system. Three electric valves are used to control the gas flow into the capillary system and for the bypasses. The use of macro devices simplifies the handling of the experimental setup and also the electronic control. Pressure drops for plasma and sample gases are accomplished by an appropriate combination of capillaries with different diameters and lengths as described in Sect. 4. 

The actual value of the regulated pressure equals the set pressure at minimum flow (ijj). Once the flow rises above minimum, the actual controlled pressure drops. This "droop" or offset is permanent and increases with flow. 

Rezzoug, S.A. Maache-Rezzoug, Z. Mazoyer, J. Jeannin, M. Allaf, K. Effect of instantaneous controlled pressure drop process on the hydration capacity of scleroglucan optimisation of operating conditions by response surface methodology. Carbohydr. Polym. 2000, 42, 73-84. 

The selection of an appropriate fixed bed reactor design for a given process is performed assessing the main limitations of these reactors. The fixed packed bed reactors can be malfunctioning due to improper temperature control, pressure drop for processes with low tolerance, and deactivation of the catalyst. 

Guillamon E, Burbano C, Cuadrado C, et al. (2008). Effect of an instantaneous controlled pressure drop on in vitro allergenicity to lupins (Lupinus albus var. Multolupa). Int. Arch. Allergy Immunol, 145 9-14. 

Instant Controlled Pressure Drop Coupled to Intermittent Air Drying.496... 

The effective diffusivity becomes smaller with shrinkage, which results in a more compact structure. A very effective intensification method can take place by proper texturing of the material using instantaneously controlled pressure drop, Die. A second airflow drying stage can then improve both the process performance and final product quality (Albitar et al. 2011). 

Albitar, N., S. Mounir, C. Besombes, andK. Allaf (2011). Improving the drying of onion using the instant controlled pressure drop technology. Drying Technology 29(9) 993-1001. 

Allaf, K. (2009). The new instant controlled pressure—Drop DIC technology, in Essential Oils and Aromas Green Extraction and Application, F. Chemat (Ed.), pp. 85-121. New Delhi, India Har Krishan BhaUa Sons. 

Allaf, T. and K. Allaf (2014). Instant Controlled Pressure Drop (DIC) in Food Processing. Fundamental to Industrial Applications. New York Springer. 

Mounir, S. and K. Allaf (2008). Three-stage spray drying New process involving instant controlled pressure drop. Drying... 

Mounir, S., T. Allaf, A. S. Mujumdar, and K. Allaf (2012). Swell drying coupling instant controlled pressure drop DIC to standard convection drying processes to intensify transfer phenomena and improve quality—An overview. Drying Technology 30(14) 1508-1531. 

Some new green extraction techniques, aimed at sparing energy and reducing costs, such as solid state and submerse fermentation, enzymatic, microwave- or ultrasound-assisted extraction, ultrafiltration, flash distillation and controlled pressure drop processing [22, 23] have been studied to improve solvent extraction. 

In this study, we used a geometry variable device to control pressure drops collocated with a hot nozzle system. We tried to improve the cell uniformity and to get a smaller cell size through an injecting molding microcellular foaming process. The results are as follows ... 

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