Steam-heat exchangers are used to raise the temperature of well effluents to prevent hydrate formation, reduce viscosity, and break down emulsions for efficient separation of oil and water. Because the steam-heat exchangers virtually eliminate fire risk, they are used on offshore platforms and in other work conditions where safety regulations do not permit the use of indirect-fired heaters.
The steam-heat exchanger requires an adequate steam supply for operation. Some rigs have a sufficient steam supply, but usually a steam generator is required.
Steam enters the vessel through an automatic control valve. The vessel contains an internal tubing bundle through which the effluent passes, a steam trap containing a steam condensate outlet, a safety relief valve, and a temperature controller. The vessel, which is equipped with two 152-mm [6-in] safety valves and a split coil, 106 mm by 106 mm [4 in by 4 in], is insulated with glass wool and an aluminum jacket. Heat from the steam is transferred to the tubing bundle and, in turn, to the effluent. A choke—with a 2-in seat, and a 3-in manifold equipped with three 31⁄16-in gate valves—is located between the effluent inlet and outlet. It allows the effluent to be preheated before and after the pressure is reduced at the choke.
All steam heat exchanger models are skid mounted