Projects

FWKO

A customer wanted to heat oil in a FWKO using surplus heat available from compressed supercritical CO2. Previous attempts to heat the oil with a shell-and-tube heat exchanger failed because of the large quantity of water in the feed stream. ETI elected to heat the oil with an internal heat exchanger bundle positioned in the oil phase, so heat would not be lost to the water phase.

 

 

The free-water knockout was sized to dehydrate 75,000 lb/h crude oil, 53.5 lb/ft3 density at 55°F, 13 cP and separate it from 1,000,000 lb/h of CO2-saturated produced water and 725,000 lb/h of water-saturated CO2 vapor. The oil was to be heated to 125°F using 163,000 lb/h of 180°F supercritical CO2. The heat exchanger bundle is 32” OD with 8” inlets and outlets and it provides heat through (90) 1” U-tubes x 0.133” thick, 316 stainless steel coils, 2531.5 ft2 surface area, 40 ft straight length, designed for 1860 psig at 200°F.

The vessel selected was a 12’ OD x 50’L vessel with internal coating and all stainless steel internals. Special internals consisted of two plate packs for oil dehydration, two plate packs for o/w separation, a special degassing inlet, baffling on the heat exchanger bundle to achieve cross flow conditions, a demisting mesh pad, and a Tore® OVD sand jet removal system. The vessel was to be elevated on piers with an adjacent piping skid, 15’W x 50’L as well as an overhead platform. The piping was constructed of 316 stainless steel.

The vessel, which is enclosed in a steel building, had a local control panel with a HMI interface. The vessel is completely automated with positioners on the control valves, an effluent oil turbine meter, an outlet water mag meter, an inlet critical flow transmitter on the supercritical CO2, and a flow transmitter on the CO2 outlet.