Seawater desalination — SWCC experience and vision

Abstract

In order to appreciate Mankind's technological advancements, one needs to present a historical overview. This applies to desalination technology (among all other human developments). Over the millennia, desalination did develop very slowly at the start and then its development started to accelerate. The author has so far traced this technology to as far back as to the third millennium BC. Arabian Peninsula and its surroundings had been the cradle of this, like quite many other, fields of knowledge and technology. Such development has left its mark also around the Mediterranean, especially in Alexandria and Athens, then much later in Italy. The Arabian Islamic Civilization has engraved several thumbprints on the path of distillation. An ingenious distiller with built-in internal reflux was found with Arabic writing below, to describe the device. Moreover, Demusquain glass was used in making lenses as solar heat concentrators for distillation. During this millennium colonialism, which brought prosperity to some through exploitation of resources and the deprivation of the colonized masses, implemented desalination as one of its tools on board ships and within the so-called prosperous new found lands. With the increase of water demand and emphasis on desalination technology due to shortage of underground resources in the kingdom, the government of Saudi Arabia established the Saline Water Conversion Corporation (SWCC) in 1974. Since the SWCC has grown and become the authority to look after all matters related to seawater desalination. At present SWCC has 27 plants producing 668MGD of desalinated water and 4115MW of electricity from existing operating plants. Additional four plants with a total capacity of 218MGD of water and 999MW of electrical power are under construction. This will take total desalinated water production to 886MGD and electrical power generation of 5114MW. The last three decades have seen a tremendous growth of SWCC along a few different lines, such as: a) enhanced production capacity of desalinated water, b) self administered operation and maintenance, c) execution of trouble shooting and applied projects, d) development of experience-based design concept, e) venturing into new technology and/or carry out modifications, into existing ones, f) promote Saudization in all disciplines of desalination. With the immense interest and concern in developing seawater desalination industry to minimize cost, upgrade performance and prolong life of plants, a Research and Development Center (RDC) was established and inaugurated in 1987 to achieve these objectives. Teh center has five sections, Thermal, Reverse Osmosis, Corrosion, Chemistry, and Ecology and Marine Biology. The center is equipped with most advanced and sophisticated equipment in addition to a multistage flash (MSF) and several RO pilot plants. The RDC helps in solving problems in operating plants thus leading to higher efficiencies and longer plant life. RDC also helps in the selection of ideal materials and chemicals for eventually achieving lower production cost. Studies to protect the environment have also been carried out. Since its inception the RDC has completed 117 projects in various aspects of desalination, some of which begot from problems encountered during plant operation. Moreover, SWCC Research and Development (R&D) and Studies and Designs (S&D) Departments are the corporate THINK TANKS for the future. SWCC activities have opened eyes into new horizons far behind the traditional ones. Lofty stands up high, as a new milestone which was brought into adaptation is nanofiltration of seawater as pretreatment, potentially for all desalination processes. In other words recent efforts at the center yielded a novel approach to membrane and thermal seawater desalination processes using nanofiltration (NF) membrane. This patented concept of using NF as pretreatment to both RO and MSF processes enhances the production of desalted water by more than 60% and reduces the cost by about 30%, yet it is an environmentally friendly process. Preliminary results of studies on NF indicate that this new concept could one day revolutionize desalination technology. Other prospective horizons are by conducting applied research on: a) design, commissioning then operation of large capacity distillers, b) hybridization of desalination processes, c) exploration of alternative energy sources for desalination, e.g., solar and nuclear, d) search for suitable and cost effective chemicals, alloys and synthetic materials, e) new design for very large number membrane elements housing (the proposed vessel is envisioned to be like a heat exchanger and/or a steam drum), f) designing, building and testing elevated top brine temperature (TBT) MSF process at (and/or above) 160°C, g) treatment and safe disposal of waste generated through better understanding of environment interactive impacts related to desalination, h) magnetically enhanced separation of seawater hardness.