SIEMENS WATER TECHNOLOGIES (WARRENDALE, PA) . . .
Engineering for the Petroleum and Process Industries (ENPPI) has selected Siemens Water Technologies to provide a produced water treatment system as part of an expansion at Saudi Aramco’s Safaniya plant in the Eastern Province, Saudi Arabia. The new system will remove high concentrations of free oil from the water stream with the dissolved gas flotation (DGF) method from Siemens, so the water can be used for subsurface re-injection. The capacity will be 850,000 barrels of water per day (BWPD). The project is scheduled to begin operation mid-year 2008.

Saudi Aramco uses injected water to maintain reservoir pressure to maximize oil production. Presently, the system handles Arab Heavy crude oil and formation water from the Safaniya oil field and Arab Medium crude oil from Zuluf oilfields. The formation water from both fields is processed and then re-injected.

Siemens Water Technologies provides the plant with produced water treatment systems which consist of vessels using proprietary DGF pump technology. The DGF pump is the heart of the system. It works by using a dual sided impeller that pulls both water and gas into the pump volute. The backside of the impeller has a “sub-atmospheric” zone that pulls vapor from the blanket gas source or other means and allows mixing with the incoming fluid. As this mixing occurs, the vapor is dissolved into the water creating micro-fine bubbles that break out of solution once a pressure drop is experienced. This pressure drop occurs once the fluids and dissolved gas are flowed across a globe valve prior to entrance into the flotation vessel.

Due to the close tolerance between the back vanes of the impeller and the back plate of the DGF pump, the vapor is sheared into micro-fine bubbles piped into a vessel or tank allowing the fine gas bubbles to attach to the oil droplets. As the gas bubble attaches to the oil droplet, the droplet floats to the surface at an accelerated rate.