DISCUSSION OF USING THERMOFLEX VS. ASPEN PLUS TO MODEL NGCC AND IGCC POWER PLANTS

摘要

For a research project for developing new clean coal processes for power plants,rnThermoflex®, from Thermoflow, Inc., was used. To validate the results from Thermoflex, arnNatural Gas Combined Cycle (NGCC) and an Integrated Gasification Combined Cycle (IGCC)rnwere modeled first in order to be compared with similar plants modeled in Aspen Plus by thernNational Energy Technologies Laboratory (NETL) of the United States Department of Energyrn(U.S. DoE). Thermoflex is a program within the Thermoflow software suite, which is mainlyrnused for modeling general thermal-flow components/processes, gas turbines, and power plants,rnwhile Aspen Plus is mainly used for designing thermodynamic and chemicalrncomponents/processes/reactors and modeling chemical plants.rnThroughout the study, the two different software programs are analyzed through theirrntreatments of various plant parameters, including the HRSG & deaerator design; the effects ofrnlow calorific value gas on the total gas turbine mass flow rate, turbine inlet temperature, andrnturbine polytropic efficiency; and mass balance capabilities (especially with regards to the steamrncycle). Multiple modeling issues are also discussed, such as local temperature matching, the usernof syngas heating during gas cleanup, determining the deaerator operating state, and verifyingrnthe deviation of the GT’s operating performance from the spec data.rnThe convenience of using built-in modules in Thermoflex is also discussed in comparisonrnwith Aspen Plus: for example, an air separation unit, an acid gas removal unit, a carbonyl sulfidernhydrolysis reactor, etc. The conclusions are: (a) the Thermoflex results match the Aspen Plusrnresults within a 1% difference in power outputs and efficiency, and (b) Thermoflex is morernconvenient for modeling the various subsystems, particularly with regard to its comprehensiverncapabilities involving the gas turbine system's performance, but is less versatile in modelingrnchemical processes, particularly those involving chemical reactions; whereas Aspen Plus is morernrobust in terms of modeling chemical reactions but requires extensive prior knowledge of therndetailed design of all relevant subsystems, and a significant amount of effort must be spent tornmodel them accurately. The capability of Aspen Plus for simulating the gas turbine system's performance is limited to using individually separate components: i.e., a compressor, a combustor (modeled as a generic reactor), and a turbine.