Waste Heat Recovery With High Pressure Steam
Heat recovery through steam generation is not commonly used offshore. However, high pressure steam can be generated from turbines or reciprocating engine exhaust gases. Since this type of system does not provide engine cooling, higher pressure steam may be generated ranging from 100 to 450 PSIG.
The most common high-pressure steam system used offshore is the hybrid steam/water waste heat recovery system. This type of system uses forced circulation of water through a waste heat unit, as with the water system shown in Figure 3200-15. The outlet of the waste heat exchanger flows to a steam separator vessel where a portion of the water vaporizes to generate steam. This steam maintains the pressure in the steam separator at a level to preclude the need for a gas blanket system. A pressure controller on the steam outlet of this vessel controls the steam pressure and, consequently, the water temperature. Hot water from this separator can be pumped to nearby users, as with a water system. At the same time, steam may be used to provide heat to nearby users.