Temperature and pressure reducers are widely used in the steam power system of petrochemical plants

which can transfer higher pressure steam to lower pressure steam for different grades of heat demands.Otherwise

generally in summer there is abundant low pressure steam in plants.Using back-pressure turbines to replace temperature and pressure reducer

as well as condensing steam turbines to recover the energy of the abundant low pressure steam are effective energy-saving methods.In this paper

an economic evaluation model is proposed for determining the critical economic point for back-pressure and condensing steam turbines.The effect of steam price or the price ratio of electricity to heat on the critical point is discussed.The results for an industrial case show that the critical powers of steam turbine are relatively low

which means that in most industrial cases

using steam turbines to save energy is beneficial.This paper provides guidance in selection of suitable steam turbine for energy saving in petrochemical plants.