Koch Membrane Filtration System Helps Profin Cut Costs

Citation

(2002), "Koch Membrane Filtration System Helps Profin Cut Costs", Pigment & Resin Technology, Vol. 31 No. 5. https://doi.org/10.1108/prt.2002.12931ead.005

Koch Membrane Filtration System Helps Profin Cut Costs

Koch Membrane Filtration System Helps Profin Cut Costs

Keywords: Microfiltration, Waste disposal, Coatings, Costs

A microfiltration system, from Koch Membrane Systems, of Stafford, UK, is reported to be helping Profin, of Redditch, UK, to cut the costs of waste disposal while ensuring optimum operation of their extensive electrophoretic paint plant.

Profin (the Protective Finishing Group Ltd) is a long-established company involved in general metal finishing, particularly for the automotive industry. It offers the latest technologies for the coating and painting of a wide range of components and press work items, including powder coating, centrifugal coating and cathodic electrophoretic painting (e-coat).

E-coating, where electrically charged paint is deposited on workpieces dipped into a paint bath, ensures a superb overall flush. However, it is important that the components to be coated are thoroughly degreased before being dipped. Profin's e-coat plant is a computer- controlled 14-stage system, the first three stages of which are dedicated to decreasing.

The first stage degreasing bath contains water with a little surfactant. Its prime purpose is to ensure that this fluid is drawn into each component through a capillary, so that no other liquor can be introduced into the components in the subsequent processing stages. The second and third stage tanks offer a thorough soak and degrease in caustic and decreasing solutions.

Previously, it had been necessary to empty the decreasing baths once a week to ensure the optimum operation of the electrophoretic coating. However, this proved inconvenient, as it was necessary to stop the plant, incurring unwanted downtime and production losses. This was additional to the expense involved in the disposal of the spent decreasing fluid, as this had first to be neutralised with acid before being tankered off-site.

In an effort to reduce these costs and to maximise the effective utilisation of the e-coat plant, Profin decided to investigate alternative methods of treating the spent decreasing solutions. Following this a Koch membrane separation system was fitted at the Redditch factory.

In operation, around 125 1/h of decreasing fluid is continuously drawn from the decreasing baths. This is first passed through a bag filter to remove any large suspended solids before being passed into a decanting and coalescing pre-treatment unit to remove any suspended solids and floating and suspended oil. The emulsion is then extracted from the fluid in a crossflow microfiltration membrane module. The filtrate from the membrane module is returned to the decreasing bath as clean washwater, containing any residual detergent, while the significantly lower volume of retentate is passed to storage barrels for subsequent, and now infrequent, removal from site.

Since the introduction of the membrane filtration plant, Profin has enjoyed considerable benefit, as managing director. Peter Smith, explains, "We have significantly reduced our waste treatment costs but, perhaps more importantly, we can operate our e-coat plant continuously, which is good for Profin and our customers."

Koch informs us that membrane filtration is rapidly gaining acceptance as a cost-effective, space-saving alternative to other available technologies. It is said to rely on the use of a thin semi-permeable membrane, which acts as a selective barrier and separates components of a feed stream on the basis of molecular size. Membrane processes are differentiated by the size of the particles they separate and are categorized into microfiltration, ultrafiltration, nanofiltration and reverse osmosis. Ultrafiltration is the most commonly used wastewater treatment process and removes a wide range of biological materials.

A range of solution for achieving oil/water separation in industrial environments is offered by Koch Membrane Systems. The company has earned a reputation as a major innovator in membrane technology, based on over 30 years experience in the field. It manufactures a complete range of membranes in tubular, multi-tubular, hollow fibre and spiral wound configurations, produced from polymeric materials.

Details available from: Koch Membrane Systems. Tel: +44 (0) 1785 272500; Fax: +44 (0) 1785 223149.