Internet Thermoflow

Products > Conventional Steam Plant > THERMOFLEX > Sample 2

Operating 900 MW Conventional Steam Plant

This is the steam cycle screen of a model of an operating power plant in the US. It is a 900 MW, single-reheat, coal-fired, conventional steam plant. This is sample file (S1-10b)Rankine_900MW STAssembly.tfx and is located in the samples directory on the Thermoflow restricted trial CD.

Steam from the boiler (modeled on a separate screen, not shown) is admitted to the governing stage of the HPT shown together with the IPT in the red region. Steam extracted from these sections heats feedwater in the parallel train of HP feedwater heaters shown in the yellow box. The LPT consists of two double flow sections shown in the green box. Steam from each LPT cylinder condenses in a separate condenser. Cooling water flows through the condensers in series, so warm water leaving the first is the cooling water entering the second. Condenser cooling water is cooled in a 25-cell cooling tower modeled using one icon. The condenser in the light blue region services the condensing feedpump turbine, a steam turbine dedicated to driving the boiler feedpump. Its cooling water flows to and from the main plant cooling tower and represents approximately 5% of total tower heat duty.

The steam turbine physical size and cost is estimated using PEACE within THERMOFLEX. This elevation view illustrates the four separate casings, HPT, IPT, and two double flow LPTs. Overall turbine length is estimated at 232 feet (71 m), and total weight including generator is 2094 US tons (1900 metric tonnes). This turbine model was constructed using the PEACE steam turbine assembly, so all section efficiencies and leakage source/destinations, and flowrates are automatically estimated for you.  The defaults were accepted for this model.

The PEACE steam turbine assembly also automatically generates the Mollier chart shown below.  The two separate condenser pressures 1.0 and 1.39 psia (69 and 96 mbar) are illustrated in this plot.