What are the differences between condensing, back-pressure, and regulated extraction steam turbines?
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What are the differences between condensing turbines, back-pressure turbines, and extraction turbines? Answer: A condensing turbine is one in which all the steam that enters the turbine is discharged into a condenser after performing work. A back-pressure turbine is one whose exhaust pressure is higher than atmospheric pressure. An extraction turbine draws out a portion of the steam that has already done work from a certain stage within the turbine to supply other users; it still has condensation equipment.
A regulated extraction steam turbine extracts a portion of the steam that has already done work from a certain stage in the turbine to supply it to other users; the turbine still has condensation equipment, or it can be a back-pressure type without such condensation equipment
Their efficiency in converting steam into work varies; the highest efficiency is achieved by the condensing type, while the lowest efficiency is seen in the back-pressure type. However, taking into account the requirements of the entire process, it is best to use a vacuum condensation type system appropriately; moreover, this type is also convenient for adjusting the compressor power.
Condensing steam turbines are now widely used; most of the turbines and syngas compressors chosen by our company are of the condensing type. CO2 compressors and the like are all such; air compressors use a suction-and-condensation mechanism, right? The syngas compressors in our plant are driven by back-pressure turbines. During this period of operation, we’ve found that it’s difficult to regulate these back-pressure turbines; several accidents have occurred as a result of the syngas compressors shutting down unexpectedly. The key issue with back-pressure type systems is that it’s difficult to determine whether the heat load at the rear should play a dominant role or the power of the compressor. At another plant, we found that the units driven by their condensing steam turbines operated very stably.
This choice depends on the actual steam balance of each factory. If a large amount of low-pressure steam is required in the process, a back-pressure type is the best option; if the demand is low, a condensing type is preferable. The regulated extraction type has not been used before, so I am not very familiar with it