This paper provides a review on the fouling mechanism and its effect onto the performance of finned tube heat exchangers in HVAC systems. Fouling tends to degrade the performance of heat exchangers by decreasing the heat transfer coefficient and increasing the air-side pressure drop across the heat exchangers. Air side fouling depends on a number of factors on the air side, including type and c...

Ultrafiltration, nanofiltration membranes and feed spacers were hydrophilized with polydopamine and polydopamine-g-poly(ethylene glycol) surface coatings. The fouling propensity of modified and unmodified membranes was evaluated by short-term batch protein and bacterial adhesion tests. The fouling propensity of modified and unmodified membranes and spacers was evaluated by continuous biofouling...

The membrane fouling index, widely used in the reverse osmosis (RO) membrane industry, is developed mainly to assess the fouling potential of particulate matter. However, the fouling potential by organic matter should also be accurately evaluated as the productivity loss by organic fouling is often more severe than particle fouling, despite its low concentration in feed water. This study was pe...

Pre-treatment is normally required to reduce or control the fouling of ultrafiltration (UF) membranes in drinking water treatment process. Current pre-treatment methods, such as coagulation, are only partially effective to prevent long-term fouling. Since biological activities are a major contributor to accumulated fouling, the application of an oxidation/disinfection step can be an effective c...

The combined fouling during ultrafiltration (UF) of surface water pretreated to different extents was investigated to disclose the roles of polysaccharides, proteins, and inorganic particles in UF membrane fouling. Both reversible and irreversible fouling decreased with enhanced pretreatment (biologically active carbon (BAC) treatment and sand filtration). The sand filter effluent fouled the me...

Anaerobic membrane bioreactor (AnMBR) can produce high-quality effluents through effective solid-liquid separation using microfiltration. During the operation of the membrane bioreactor system, membrane fouling is one of the main problems. Several models have been proposed to understand the mechanisms of fouling of the membrane. Usually, cake formation and pore blocking are found to be the main...

The Propose of this paper is to introduce a new model for crude oil fouling in preheat trains of crude distillation unit. The experimental results of Australian light crude oil with the tube side surface temperatures between 200-260 oC and fluid velocity ranged 0.25 to 0.4m/s were used. The activation energy of chemical reaction depends on the surface temperature has been calcula...

We investigated effects of microfiltration (MF) on heat transfer fouling tendencies of thin stillage. A stainless steel MF membrane (0.1 micron pore size) was used to remove solids from thin stillage. At filtration conditions of 690kPa, the MF process effectively recovered total solids from thin stillage. Thin stillage was concentrated from 7.0% to 22.4% solids with average permeate flux rates ...

This paper is a preliminary study that deals with time-optimal control of a batch membrane diafiltration processes where fouling of the equipped membrane is pronounced. We account for the membrane fouling by its dynamic model where the pore blocking mechanism applies. It is assumed that due to the deposit of foulants, the radius of membrane pores decreases and the part of membrane surface becom...

The importance of the multiphase fluid dynamics for fouling mitigation in MBR systems has been widely acknowledged with air sparging having been applied commercially for about 20 years. However, the effects of air scouring are still not fully understood since the transient orthogonal and parallel flows as well as turbulent eddies created by bubbling generate complex hydrodynamic flow fields in ...