베올리아 소유의 Membratek사에 의하여 2천500개 이상의 tubular RO 멤브레인이 남아프리카 공화국의 coal-to-liquid 정유플랜트에 교체용으로 설치 완료됐다.
이 플랜트의 생산성 성능 개선을 위해 추진된 것으로 124만불 투자가 이루어 졌으며 이번 관형막 멤브레인의 교체 및 개선으로 다양한 정제과정에서 발생되는 ash water를 재이용 할 수 있으며 더불어 전체 유입 취수량을 줄이고 발생되는 오염물질을 지표수로 배출하는 양을 획기적으로 제한 할 수 있게 된다.
기존의 관형막 멤브레인 시스템은 이미 2001년에 베올리아에서 설치한 것으로 이번 개선작업으로 플랜트의 가동시간을 증가시킨 효과도 얻게 되었다. 베올리아 공급의 관형막 멤브레인은 고탁도 및 유기물 및 염분이 많이 함유된 열악한 원수 환경에 적합한 멤브레인으로 알려져 있으며 또한 전처리 및 케미칼에 의한 조절이 최소한도로 요구되고 있다. 일반적인 수명은 4-5년이며 모듈화된 디자인으로 멤브레인 교체가 용이한 것도 특징이다.
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Tubular membranes replaced at South Africa coal plant
More than 2,500 tubular reverse-osmosis (TRO) membrane modules have been replaced at a South African coal-to-liquids refinery by Veolia?owned Membratek in a subcontract.
To keep up with improved production performance at its refinery in Secunda, Sasol Limited has successfully completed a R 13 million (US$ 1.24 million) upgrade of its water treatment plant. The TRO plant helps to reuse water from the facility's ash water system for various refinery processes, reducing overall raw water intake while limiting the release of potentially harmful pollutants into surface water systems.
The TRO plant was originally designed and built in 2001 by Veolia Water Solutions & Technologies South Africa, then known as Weir Envig. The recent upgrade was foreseen in the plant's original designs, which significantly reduced engineering time during changeover while ensuring maximum plant uptime.
The expansion was implemented and commissioned by Malutsa, a 70% black-owned water projects company affiliated with the Veolia Water multinational.
"Membratek was subcontracted to manufacture 2,620 unique 4.3 m TRO membrane modules," says Abrie Wessels, regional general manager at Veolia. "These modules are ideally suited to the harsh conditions, such as high turbidity, organics and salinity experienced at this unit. After Sasol's own pilot studies, Membratek membranes proved to be the best solution for this application."
Featuring a large 12 mm bore construction and a robust design, Membratek's TRO membranes were chosen for Sasol's most recent upgrade based on their unique ability to resist fouling, even in highly demanding operating circumstances. "The membranes are superb at dealing with the variable nature of the feed water, requiring minimal pretreatment and chemical conditioning which reduces running costs significantly," says Wessels.
Regular mechanical cleaning using a sponge ball will further reduce operational costs of the TRO plant, while regular testing on site, facilitated by the unique membrane train design, ensures that membranes at the end of their useful lifespan are identified and replaced with minimal impact on standard plant operations.
"On average, Membratek tubular membranes have proven to have a typical lifetime of 4-5 years at this Sasol plant. Due to the modular nature of the system, membrane replacement is an easy and non-invasive task facilitated by a steady supply of replacement modules," says Wessels.
[출처 = Desalination & Water Reuse / 2014년 4월 4일]