Case Study Detail
Al Shuaibah Seawater Desalination Plant
Introduction
Seawater desalination using the reverse osmosis process is now the least expensive, most environmentally friendly desalination technology available today. Advancements in membrane technology, as well as improvements in pump efficiency, have helped make seawater reverse osmosis (SWRO) a viable alternative to traditional thermal methods. However, the most significant advancement in recent years – making membrane-based desalination a truly cost-effective technology – has been the introduction of isobaric energy recovery systems, such as the Energy Recovery, Inc. (ERI) PX™ Pressure Exchanger (PX™) device.
The Al Shuaibah SWRO Plant
The country of Saudi Arabia must satisfy its water needs by either piping in water from other areas or by desalinating seawater. Jeddah, the country’s second largest city with 3.4 million residents, is situated on the coast of the Red Sea and, therefore, has a ready supply of seawater. The Al Shuaibah SWRO plant was designed primarily to provide for the personal water needs of Jeddah’s population, along with minor industrial water needs. Saudi Arabia plans to rely on independent entities to produce fresh water, which it will buy via the Saline Water Conservation Corporation state water agency.
The Challenge: Achieving Positive ROI In A Region With Low-Cost Power
A significant hurdle existed for Al Shuaibah’s Engineering, Procurement, Construction (EPC) contractor, Doosan Heavy Industries of Korea, with the Al Shuaibah SWRO plant – the availability of extremely low-cost power in the Gulf region. In some cases, power costs are subsidized by the government. This creates a unique challenge in terms of return on investment (ROI) in that the lower the power costs, the harder it is to justify power conservation expenditures.
The Innovation: Isobaric PX Technology
The desalination market had shifted over the past three to four years from centrifugal technology as a means of energy recovery to the more recent isobaric technology, the most advanced technology available in terms of energy efficiency. Doosan had previous experience with other desalination energy recovery technologies, including hydraulic turbines and centrifugal methods, but the Al Shuaibah plant was Doosan’s first experience with isobaric technology. It was also its first time designing and building a membrane SWRO plant in the Kingdom of Saudi Arabia.
Doosan acquired U.S. subsidiary Doosan Hydro Technologies, which in 2008 was named Desalination Company of the Year by Global Water Intelligence and the International Desalination Association. Doosan Hydro Technologies had extensive expertise in designing with isobaric technology, including with ERI’s PX device line of state-of-the art energy recovery devices.
Doosan worked with the client, Arabian Company for Water & Power Projects (ACWA Power Projects), on Saudi Arabia’s Al Shuaibah Expansion Independent Water and Power Project (IWPP) and selected isobaric technology for the project, specifically ERI’s PX technology. Although isobaric technology, in some cases, has a higher initial cost, it provides the plant operator with a more rapid ROI over the life of the plant compared to older, less efficient technologies.
With isobaric technology, the Al Shuaibah plant is projected to save 19 megawatts of energy and reduce CO2 emissions by 98,000 tons annually – a much greater environmentally friendly solution with a lower carbon footprint than would have been possible using older technologies.
The Decision: ERI
After careful review, ERI was the obvious choice for Doosan based on its PX technology’s performance, reliability and ease of operation. ERI’s R&D and manufacturing expertise, on-site commissioning services and training offerings were also significant factors in Doosan’s final decision. ERI provided 230 of its PX-220 units – 10 trains with 23 units each – as well as supply, process review and start-up support services to the project to help ensure a sound energy recovery design for the entire plant.
Included in all of ERI’s solution packages for clients is the opportunity to tour ERI’s manufacturing facility and inspect the equipment prior to shipping. In addition, clients have the option of sending their plant operators and engineers to ERI’s “PX School” for comprehensive training on its state-of-the-art PX technology. The company provides field service assistance as well as start-up and commissioning services.
The Result: Doosan Delivers “First Water” In Record Time
The time between equipment delivery and plant completion to making “first water” is critically important in the desalination industry. The Al Shuaibah plant took 26 months to complete the process, an impressive timetable given the remote location and local conditions. A more typical interval for a project of this size and magnitude would be 36 months. ERI team members ensured that on-site installation and testing of the PX units satisfied Doosan’s performance requirements and enabled this record time.
The Al Shuaibah Expansion SWRO plant – the first large-scale desalination plant in Saudi Arabia to use isobaric energy recovery devices – will consume at least 40 percent less energy per unit permeate than any other SWRO plant in the country. Moreover, its ERI PX Pressure Exchanger devices deliver exceptional process efficiency, productivity and flexibility with much lower environmental impact than turbine-based SWRO technology for a truly viable, cost-effective solution to the region’s water needs.