WATER & WASTEWATER MANAGEMENT


way for the introduction of product- lubricated bearings that require no oil or grease. Tat saves operators the expense and complexity of forced oil lubrication systems, reduces the risk of product contamination and enables state-of-the-art efficiency without compromising reliability. Improvements in hydraulic


performance have been achieved by replacing axial split casing pumps with ring section designs. Initially, this approach was only applied to smaller RO trains, but these pumps are now available with capacities of up to 1,000m3


for larger trains. Hydraulic improvements came also


in low pressure applications, where traditionally single stage, double suction pumps were traditionally used. Today, even at higher capacities, users are now choosing cost-effective end suction overhung pump designs with higher efficiencies and extremely good suction performance in a highly reliable way. Pump control technology has improved dramatically too, thanks to the availability of reliable and cost-effective variable speed drives. Tese give users the flexibility to run pumps over a wider range of operating conditions, minimising the need to regulate flows via valve throttling. Tey also allow pumps to operate closer to their best efficiency point, avoiding unnecessary impeller trims that can have a negative impact on overall efficiency. While the first variable speed drives used in the industry were affordable only for low voltage drivers


A choice of pump designs ensures the most efficient solution for each project


per hour


for low pressure pumps, the availability of medium voltage drives has extended the benefits of this approach to high-pressure pumps.


ECONOMIES OF SCALE Perhaps the most important driver of improved pump efficiency in RO plants leading to substantially reduced specific consumption has been scale, since the efficiency of a centrifugal pump increases with its capacity. Te first opportunity to capture scale advantages came with the introduction of larger RO trains, which increased from a maximum of 15,000m3 per day in 2001, to 25,000 or even 30,000m3


per day.


Te next opportunity came from a change in system architecture. Te creation of the Pressure Centre concept allowed the introduction of very large pumps that supply multiple RO trains through a


As a leading pump specialist, Sulzer has decades of


experience in the RO sector


manifold system. Plants using this design were first introduced in the mid-2000s and it has since become the standard approach for large SWRO facilities. Sulzer has been supplying high pressure pumps for such Pressure Centre concepts from the beginning. Using a two-stage solution, the high-pressure pumps used in those first Pressure Centre facilities had a high-pressure flow of around 2,500m3 per hour and achieved efficiencies of around 88%. Today, Sulzer is delivering high-pressure pumps for the largest plants with capacities in the range of 3,500 to 4,000m3 90%.


per hour and efficiencies above While efficiency improvements on the


high-pressure pump are getting close to the physical limits, potential improvements are coming from other pumps services in a SWRO plant. Tis performance is being matched by the company’s latest low- pressure end suction pumps, used in other continuous services like the intermediate, the low-pressure booster or the second pass pumps, which can also achieve efficiency ratings of more than 90%.


Te desalination sector is continually


advancing, with incremental improvements in scale, efficiency and reliability. Each new project aims to reach the limits of performance, and every year the sector finds ways to push those limits just a little further. Sulzer is proud to play its own part in that ongoing improvement process. Ultimately, everyone has one common goal: delivering more affordable fresh water to the people that need it most.


Antonio De La Torre is with Sulzer. www.sulzer.com


www.engineerlive.com 29


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52