Titanium Industrial Business Opportunities in Global Desalination
Titanium’s superior corrosion resistance to seawater and high strength make it a material of choice for the worldwide desalination industry. As such, executives taking part in the closely watched World Industry Demand speaker panel, which addresses the annual TITANIUM Conference and Exhibition hosted by the International Titanium Association (ITA), typically identify desalination as an important global market for titanium. There are two basic technology categories for desalination systems: membrane processes (primarily reverse osmosis) and thermal distillation (evaporation). Thermal distillation is broken out into three sub categories: multi-stage flash evaporation (MSF), multiple-effect evaporation (MED), and mechanical vapor compression (MVC). Titanium finds most of its applications in the thermal distillation category, used for tubing, valves and plate heat exchangers. By contrast, titanium has only limited use in reverse osmosis systems, primarily in pump heads. Industry estimates suggest about 60 percent of desalination plants in the world use reverse osmosis technology due to its flexibility and efficiency in terms of energy consumption.
Thermal distillation is the main desalination technology used in the Middle East. The world’s two largest thermal distillation desalination projects will be located in Saudi Arabia. The Ras Al-Khair MSF desalination plant, slated for completion in 2014, will require 6,000 metric tons of titanium, providing 1 million cubic meters per day (m3/day) of water to 3.5 million people in Saudi Arabia’s Riyadh region and additional 25,000 m3/day supply to Ma’aden Aluminum Complex. Thirty percent of this plant’s output will be produced by reverse osmosis. The Yanbu 3 MSF plant, slated for completion in March 2016, will supply 550,000 m3/day of water to nearly 2 million people in the industrial city of Yanbu and the nearby Medina region. Each desalination plant in Saudi Arabia will use between 5,000 and 6,000 metric tons of titanium. Doosan Heavy Industries of South Korea is the prime contractor for both projects. Executives at Valtimet, Boulogne Billancourt, France, a subsidiary of French industrial conglomerate Vallourec, say that, for the near term—except for major contracts like the two projects in Saudi Arabia—desalination is a moderate industrial growth market for titanium, with typical annual demand of around 500 metric tons. However, higher growth can be expected to ramp up in the next five to 10 years. In addition to the Middle East, Valtimet executives see opportunities for titanium unfolding in thermal desalination plants being planned in China.
For thermal desalination, when MSF technology is chosen, Valtimet officials say titanium competes with copper alloys and the choice depends on the relative cost of titanium compared with copper. MSF technology is being specified for large outside-diameter (OD) tubing (above 40mm) and long tubes (above 20m). When MED technology is chosen, titanium competes with stainless steel or aluminum/brass. Tubes for MED are closer to power-generation tubes, with an OD of 25mm and length around 13m. Valtimet has several research and development projects underway for desalination applications, such as thinner titanium tubes to reduce weight and cost, as well as enhanced surface area to improve heat-exchange efficiency. Valtimet touts itself as the leading supplier of titanium welded tubes for desalination applications, with an overall annual production capacity of nearly 6,000 metric tons. It has five installations that produce titanium tubes: Morristown, TN; Les Laumes, France; Incheon, South Korea; Xian, China; and in Hyderabad, India. Leon Awerbuch, director and past president of the International Desalination Association (IDA), Topsfield, MA, said the basic goal for thermal desalination technology is to evaporate and condense seawater efficiently. Awerbuch said heat-transfer tubes are the heart of the MSF process, and that MSF plants typically offers a reliable, 40-year life span. MSF typically has an operating range of more than 110 C (230 F). Titanium is considered the material of choice for this technology in Saudi Arabia, competing against copper/nickel and aluminum/brass. As for MED, seawater is sprayed on the outside of titanium tubes and vapor is condensed inside the tube. As the name suggests, there are multiple stages of evaporation and condensation in the MED process. In MED, the feedwater preheaters and final condenser tubing are made from titanium. The operating range for MED is 65 to 75 C (150 to 170 F).
In order to remain cost competitive with other metals, titanium must continue to strive for thinner-wall tubing. For MFS, titanium can reach 0.7mm for tube walls, while in MED the goal is to achieve 0.4mm. Awerbuch concurred with Valtimet’s forecast for near-term global market development, noting that China currently is evaluating MED desalination projects, which would offer growth for titanium. By contrast, Australia is a major global desalination market, but most plants there—such as Victorian Desalination Plant on the Bass Coast—use reverse osmosis technology, which favors the use of high-grade stainless steel. “Hybrid” desalination is a trend that has emerged in recent years, where a facility installs thermal and reverse osmosis/membrane technologies (a 70/30 mix), which provides cost flexibility for the operator, according to Awerbuch. All thermal desalination plants are combined with power plants when exhaust steam from the turbine is the source of energy for desalination. Another potentially lucrative business trend for applications in the United States involves redeploying thermal desalination technology for burgeoning hydraulic “fracking” (injecting water and chemicals deep underground) to extract natural gas from underground shale deposits. While fracking offers the promise of producing high volumes of natural gas to meet ever-increasing energy demands, the process has garnered its share of criticism regarding environmental issues. In particular, a major environmental concern is the disposal of “flowback” water produced after underground injection, which has a higher salt content than seawater. As a result, proper disposal of this flowback water is problematic. Thermal desalination can be used to clean up the flowback water, allowing it to be reused for another fracking project. Awerbuch said this would create a new market for desalination technology. “In my opinion, titanium would clearly be the material of choice for this application,” he said. In addition to MED and MSF, MVC desalination is a candidate for this application. Water vapor is compressed and passed over a heat exchanger condenser, and the resulting water is stored for reuse. According to information posted on its Web site (www.idadesal.org), the IDA, a non-profit organization, describes itself as the world’s leading resource for information and professional development for the global desalination industry.