Fouling cleaning

Smaii-tube Tefion Chemical resistance of tubes no tube fouling. Clean fluids, condensing, cross-exchange. Low heat transfer coefficient. 2.0-4.0... 

Fouling Cleaning I Power extra I Production loss I Membrane replace (6-7)... 

Membrane compaction and fouling-cleaning studies by ultrasonic time-domain refiectometry... 

F.J. Mueller, W. Krieger, W. Kissing and R. Reiner, Fundam. Appl. Surf. Phenom. Assoc. Fouling Clean. Food Process., Proc. Int. Workshop, (1981) 343 [Chem. 

Pilot-plant experiments to obtain complementary information - continuous tests, new geometries, new operating conditions, mid-long term fouling, cleaning - and simulation with a strict compliance with basic rules for scaling-up (all the dimensionless numbers are kept constant). 

The author wants to thank Dr. H. S. Muralidhara for his careful review of the manuscript. He also made many useful suggestions and some contributions pertaining to the discussions on membrane fouling, cleaning and concentration polarization. 

In the situation of no fouling (clean membrane) and feed water completely free of any solutes, and assuming laminar flow through capillary tubes of radius r, the Hagen— Poiseuille law was obtained ... 

There is a continuing need for better ways to characterize membranes and membrane processes. In particular, noninvasive, real-time techniques are needed for characterizing membrane fouling, cleaning, module hydrodynamics, compaction, formation, morphology, and quality control. There is a particular need for characterization techniques that can be readily adapted to commercial membrane modules and processes. 

Are best if equipment needs regular cleaning because of fouling or needs regular sterilization. 

Figure A3.10.2 The influence of corrosion (C) and marine fouling (F) on the perfonnance of a steel ship dry docked amuially for cleaning and painting [5].

Fouling of the pH sensor may occur in solutions containing surface-active constituents that coat the electrode surface and may result in sluggish response and drift of the pH reading. Prolonged measurements in blood, sludges, and various industrial process materials and wastes can cause such drift. Therefore, it is necessary to clean the membrane mechanically or chemically at intervals that are consistent with the magnitude of the effect and the precision of the results requited. 

The subsequent improvement of the physical and chemical characteristics of these membranes, their incorporation into machines, and the development of procedures to prevent or clean surface-fouling films were the principal areas of significant advancement. By 1990, the industrial ultrafiltration market had grown to an estimated (90-100) x 10 . ... 

Gleaning. Fouling films are removed from the membrane surface by chemical and mechanical methods. Chemicals and procedures vary with the process, membrane type, system configuration, and materials of constmction. The equipment manufacturer recommends cleaning methods for specific apphcations. A system is considered clean when it has returned to >75% of its original water flux. 

Flux response to concentration, cross flow or shear rate, pressure, and temperature should be determined for the allowable plant excursions. Fouling must be quantified and cleaning procedures proven. The final design flux should reflect long-range variables such as feed-composition changes, reduction of membrane performance, long-term compaction, new foulants, and viscosity shifts. 

When fouling occurs, even mechanical cleaning does not remove all traces of the bio film. Previously fouled and cleaned surfaces are more rapidly colonized than new surfaces. Residual biofilm materials promote colonization and reduce the lag time before significant fouling reappears. 

Reverse Osmosis Membrane Cleaning. Citric acid solutions are used to remove iron, calcium, and other cations that foul ceUulose acetate and other membranes in reverse osmosis and electro dialysis systems. Citric acid solutions can solubilize and remove these cations without damaging the membranes (94—96). 

The success of EDR ia water demineralization has appareatly resulted from its greater tolerance of particulate and fouling matter compared to reverse osmosis greater forgivingness of process upsets greater tolerance for unskilled operators simplicity ia desiga and constmction of EDR stacks compared to reverse osmosis modules the abiHty to iaspect, clean, or replace one membrane at a time the existence of a comprehensive global sales and... 

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