Fuel allocation in a combined steam-injected gas turbine and thermal seawater desalination system

摘要

Fuel allocation in a combined steam-injected gas turbine(STIG)power generation and multi-effect thermal vapor compression(METVC)desalination system is studied,using seven methods:(1)Products Energy Method,(2)Products Exergy Method,(3)Power-Generation-Favored Method,(4)Heat-Production-Favored Method,(5)Basic Exergetic Cost Theory,(6)Functional Approach and(7)Splitting Factor Method.The latter three are thermo-economics-based.Two sample cases are calculated.The methods and results are compared and discussed.The main conclusions are:it is important to carefully choose suitable methods to perform fuel allocation in a dual purpose desalination systems(here a combined STIG-METVC system)since different methods produce very different results;The results obtained from Methods(1)and(5)are unreasonable,and those from Methods(3)and(4)set the range within which the fuel allocation values must reside;Although thermoeconomic methodologies are considered to be the most rational for cost attribution of multi-product systems,false results could be reached if they are not suitably used;When sufficient information is unavailable for performing a thermoeconomic analysis,Method(2)can be taken as an approximation for fuel allocation,as well as for the distribution of fuel cost and combustion pollutant emission,between power and water in a STIG-METVC system.A recommended fuel allocation analysis procedure,based on this study and with some generality for other gas-turbine power plant dual purpose thermal desalination systems,was outlined.