Abstract: An Energetic and exergetic analysis is conducted on a
Steam Turbine Power Plant of an existing Phosphoric Acid Factory.
The heat recovery systems used in different parts of the plant are also
considered in the analysis. Mass, thermal and exergy balances are
established on the main compounds of the factory. A numerical code
is established using EES software to perform the calculations
required for the thermal and exergy plant analysis. The effects of the
key operating parameters such as steam pressure and temperature,
mass flow rate as well as seawater temperature, on the cycle
performances are investigated. A maximum Exergy Loss Rate of about 72% is obtained for the
melters, followed by the condensers, heat exchangers and the pumps.
The heat exchangers used in the phosphoric acid unit present
exergetic efficiencies around 33% while 60% to 72% are obtained for
steam turbines and blower. For the explored ranges of HP steam
temperature and pressure, the exergy efficiencies of steam turbine
generators STGI and STGII increase of about 2.5% and 5.4%
respectively. In the same way optimum HP steam flow rate values,
leading to the maximum exergy efficiencies are defined.
Abstract: Recently ORC(Organic Rankine Cycle) has attracted
much attention due to its potential in reducing consumption of fossil
fuels and its favorable characteristics to exploit low-grade heat sources.
In this work thermodynamic performance of ORC with superheating of
vapor is comparatively assessed for various working fluids. Special
attention is paid to the effects of system parameters such as the evaporating
temperature and the turbine inlet temperature on the characteristics
of the system such as maximum possible work extraction from
the given source, volumetric flow rate per 1 kW of net work and
quality of the working fluid at turbine exit as well as thermal and
exergy efficiencies. Results show that for a given source the thermal
efficiency increases with decrease of the superheating but exergy
efficiency may have a maximum value with respect to the superheating
of the working fluid. Results also show that in selection of working
fluid it is required to consider various criteria of performance characteristics
as well as thermal efficiency.