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D e v e l o p m e n t in o i l -water s epara t ion At the Manufac tur ing Week exhibi t ion (19-21 October 1993, Bi rmingham, UK), Zander (UK) will l a u n c h an u p d a t e d vers ion of i ts Aquaffl p roduc t for separa t ing emuls ions , pa r t i cu la r ly compressor condensate .

Named the Aquafll K, the range h a s five sizes capable of p rocess ing be tween 2000 and 15 000 l i tres of condensa t e a week.

Using a complete ly new flow a r r angemen t the emuls ion is p re t r ea t ed by removing any non-emusff ied oil by flotation. The emuls ion p a s s e s ac ross a ceramic crossflow m e m b r a n e which allows water molecules to p a s s through, bu t rec i rcu la tes the oil unt i l it is so concen t ra ted tha t it is p u m p e d into a conta iner for disposal . The Aquaffl concen t ra tes the emuls ion from a typical compressor ins ta l la t ion by a rat io of 600 to 1.

Recently, for example, a compressor s ta t ion with an ou tpu t of 2200 scfm p roduced 90 gal lons of condensa te a day. This cost £300 a week for disposal .

Aquafll K fo r separating emulsions.

Using an Aquafll sys tem the equivalent cost is e s t imated to be £300 a year.

Compressed air is u sed to f lush the m e m b r a n e at regular intervals, and a cleaning cycle, us ing detergent, au tomat ica l ly opera tes according to the applicat ion.

Zander h a s developed a por table test rig which can be u sed to tes t emuls ions for sui tabi l i ty of appl icat ion before purchase .

Further Information from: Nigel Morris, Zander (UK) Ltd, PO Box 2585, Tamworth, Staffordshlre, B77 4QZ, UK. Tel: +44 (0)827 51242. Fax: +44 (0)827 61904.

Col laborat ion for PEM fuel cel l s y s t e m US-based Dow Chemical Co and Bal lard Power Sys tems Inc of Vancouver, Bri t ish Columbia, Canada, have agreed to col laborate in developing and commercial iz ing na tu ra l -gas - fue led pro ton exchange m e m b r a n e (PEM) fuel cell sys tems.

Such sys tems produce less pol lut ion than conventional power genera t ion because the only by-produc t s are water, hea t and lower a m oun t s of carbon dioxide, Dow says. The fuel cells convert hydrogen into electricity, wi thout combust ion.

(Source: Free Press, Detroit, 14 July 1993)

Mem brane and superc tical CO2 e t h a n o l e x t r a c t i o n Recovery or removal of e thanol from aqueous solut ions is needed in m a n y indus t r i a l p rocesses and in the clean up of was te s t reams. Because of the relatively high affinity between e thanol a n d water, a large a m o u n t of energy is required to achieve separa t ion us ing the convent ional evapora t ion and dis t i l la t ion techniques . Less energy-consuming techniques for th is p rocess have been investigated, which include adsorpt ion, l iqnid extraction, reverse osmosis m e m b r a n e processes , and supercr i t ica l fluid extraction.

In J. Membrane Sci., 81, 1993, pp 273-285, the separa t ion of e thanol from aqueous solut ion by a method incorpora t ing supercr i t i ca l CO2 with reverse osmosis is d i scussed . The separa t ion was carr ied out in a m e m b r a n e module tha t cons is ted of two c h a m b e r s divided by the membrane . The supercr i t ical CO2 a n d aqueous solut ion flowed in paral le l into one

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chamber, while the other chamber was empty and kept at 1 a tmosphere pressure. By introduction of supercritical CO2 into the reverse osmosis operation at a proper time, the ethanol rejection of the present method was significantly better than that of reverse osmosis separat ion and the supercrltical CO2 extraction method. The effects of liquid and CO2 flow rates, ethanol and salt contents of the feed solution, as well as pH on ethanol rejection, were also examined.

Further information from: Chung-Sun Tan, Department of Chemical Engineering, National Tslng Hua University, Hslnchu 30043, Taiwan.

Micro f i l t ra t i on d i s i n f e c t i n g s e w a g e With increasing awareness of pollution and stricter regulations for the discharge of effluents, it is becoming increasingly necessary to disinfect effluents prior to release. However, all the disinfectants normally used have the disadvantage of being extremely sensitive to the effluent quality ups t ream of the disinfection stage. Thls has led to increased interest in the process of mlcroflltration, a purely physical separation method.

Results published In Brat. Scl. Tech., 27, No. 7--8, pp 19-27 were obtained from the initial phase of a s tudy to investigate the feasibility of using microflltration for disinfecting sewage. Despite the poor quality of the secondary effluent in the test, the microflltration process eliminated all faecal bacteria and tenia and ascaris eggs.

A 3-week trial of dead-end microfiltration of an effluent of very good quality confirmed the ability of the process to function for a long period without chemical cleaning, while continuing to perform well. In addition, a comparison between dead-end microfiltration and crossflow filtration has so far Indicated that the crossflow process may prove more enduring when considering permeate flux. Further trials are required to confirm this tendency.

Further informatlon from: Anjou Research, Compagnle Generale des Eaux Research Center, Chemin de la Digue, 78600 Matsons Lafflte, France.

I n o r g a n i c m e m b r a n e s - - cal l for papers The Third International Conference on Inorganic Membranes will be held at Worcester Polytechnic

Institute, Worcester, Massachuset ts , USA, on 10--14 Ju ly 1994. The theme is 'Looking ahead to the next generation of inorganic membranes ' , and one-page abstracts should be submitted to Professor Y.H. Ma before 1 November 1993.

The main proposed topics of the conference are:

• New inorganic membranes, organo-lnorganic membranes, nanoftltration membranes , catalytic or electrochemlcally active membranes .

• Membrane formation mechanisms, fundamental studies on formation processes.

• Theoretical and experimental aspects of mass transfer and separation phenomena: sorption, fouling, t ransport in microporous membrane reactors, environment applications, etc.

• Technlco-economlc aspects of membranology development.

• High temperature separations and catalytic applications.

• Prospects. A prize of US$250 plus a free registration will be

awarded to the best s tudent paper submit ted to the conference, either in fundamenta l research or in special application for Its technical impact. Two runners -up will be selected to receive a free registration plus a $150 prize. Student ' s wishing to enter this contest should submit both a one-page abstract and an extended abstract for evaluation.

Further Informatlon from: Professor Y.H. Ma, ICIM3-94, Chemical Englneerlng Department, Worcester Polytechnic Institute, 1 O0 Institute Road, Worcester, MA 01609, USA. Tel: +1 508 831 5398. Fax: +1 508 831 5853.

R e m o v i n g d y e s by low p r e s s u r e UF The conventional methods for removing barely-degradable dyes from aqueous solutions m chemical (coagulation) or biological (activated sludge) - - have in the past been inefficient, which has lead to research being directed towards pressure-driven membrane techniques.

The removal of dyes from aqueous solutions by the low pressure batch UF method has been studied by researchers in Taiwan (Sep. Scl. Technol., 28, 11 & 12, pp 2049-2059, 1993). Seven dye compounds were used in these studies, which were performed at 22°C. Experiments to investigate factors affecting membrane performance, such as the hydraulic permeability and the rejection coefficient, were carried out. These included initial dye concentration, the operating pressure, as well as the membrane material and the ionic nature of the dye molecules.

It was shown that the hydraulic permeability of dyes decreases with increasing molecular weight,

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