Turbines, steam multistage condensing

A multistage compressor, driven by a steam turbine, compresses the cooled gas. LP and HP condensates are stripped in two separate strippers where medium gasoline is produced and part of the C3+ cut is recovered respectively. A caustic scrubber removes acid gases. 

Steam turbines competitive above 75 kW condensing 2 kg/h steam/kW with 1.8 m condenser surface area per kg/h steam. Multivalve, multistage efficiency 42 to 78%. 

Five principal drivers are used for multistage centrifugal compressors. These include condensing turbines, topping turbines, electric motors, gas turbines, and steam turbines. Electric motor drives generally are used in regions where cheap power is available. Steam turbines are usually inexpensive to operate and can provide up to 18,000 rpm. Condensation turbines usually run at lower speeds of between 10,000 to 14,000 rpm, while gas turbines tend to be the most expensive to operate and usually run in the range of 5,000-6,000 rpm. 

An increase in the average temperature during the heat-addition process can also be accomplished by regenerating the steam. A portion of the partially expanded steam between the stages of a multistage turbine is drawn off to preheat the condensed liquid before it is returned to the boiler. In this way, the amount of heat added at low temperature is reduced. So the average temperature during the heat-addition process is increased. 

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