Modelling IGCC Plants Using the Simulation Tool Ebsilon Professional

Transcription

1 Mdelling IGCC Plants Using the Simulatin Tl Ebsiln Prfessinal Dr. Reiner Pawellek, STEAG KETEK IT GmbH, Zwingenberg Abstract The effrts fr a reductin f the CO2 exhaust und the develpment and enhancement f technlgies, which are nt state-f-the-art fr the pwer plant industry f tday, is a challenge nt nly fr plant peratrs and planners, but als fr develpers f sftware tls used fr planning, design and supervisin f pwer plants. Using the example f the pwer plant simulatin system Ebsiln Prfessinal, which is established in the market fr 15 years, it is demnstrated which requirements are applied t such a prgram and hw Ebsiln is meeting these requirements. We had t cnsider tw aspects: Firstly, standard cmpnents were develped t allw mdelling cycles in the familiar simple way. Additinally, a platfrm fr the integratin f actual results f research and fr experiments with the sftware is needed. This was implemented by a graduated cncept frm user-adaptable macrs up t freely prgrammable cmpnents. 1. Why Cycle Calculatins? The different appraches fr a CO2 reductin are based n the integratin f new technlgies and standard technlgies where much experience is available. T evaluate the benefit f such a plant it is imprtant t cnsider the ttal perfrmance f all cmpnents tgether. With a reliable cycle calculatin, it is pssible t examine the influence f different tplgical variatins and different parameters like temperatures and pressures n physical quantities and perfrmance factrs. Even thugh the CO2 reductin is the majr target, it is reasnable t perfrm an ptimizatin with regard t efficiencies and csts as well. 2. Demands n Simulatin Tls fr New Technlgies A simulatin tl must be able t emulate the phenmenlgical behaviur f all cmpnents in rder t achieve results which are clse t the behaviur f the real plant. Even if the detailed cmpnent behaviur is nt already knwn, the simulatin tl is able t cnsider physical (and chemical) fundamentals like mass balances, energy balances, elementary balances, laws fr pressure lsses, chemical equilibriums, t describe the basic behaviur.

2 On the ther side, it is necessary t have the flexibility t include additinal knwledge due t the prgress in research, new experiences and custmer-specific investigatins. The prgram shuld supprt switching between calculatin mdes and specificatin mdes fr all cmpnents. In this case, yu can either use the prgram t calculate certain results (e.g., a cmpsitin at an utlet) r yu can include results frm ther surces, either calculatins frm ther prgrams, manufacturer data r measurement data as an input fr the simulatin prgram, adapting the behaviur f cmpnents by characteristics and/r plynmials r even neural netwrks, extending available material tables by wn specificatins r the integratin f external material libraries, custmizing the cmpnent behaviur r even creating wn cmpnents accrding t individual requirements. 3. Ebsiln s Cntributin fr the Applicatin f New Technlgies 3.1 Targets Ebsiln is well-knwn as a plant simulatin tl. Its main purpse is the calculatin f thermdynamic quantities (enthalpies, pressures) and mass flws in the water/steam cycle and the air/flue gas path. It is restricted t thermdynamic equilibrium states and usually applies a phenmenlgical apprach t describe plant cmpnents. Therefre, a detailed knwledge abut cmpnents (like gemetry r the internal functinality) is nt required. Yu can just specify a the majr parameters (like efficiencies r terminal temperature differences) and use characteristic lines r adaptatin plynmials t define the ff-design behaviur. The great advantage f Ebsiln is the handling f large and cmplex systems. While the graphical user interface allws t cnstruct such mdels in a cmfrtable way, the Ebsiln calculatin kernel yields stable results within a few secnds, even in case f thusands f variables. In additin t the simulatin kernel, Ebsiln ffers data recnciliatin, a script language (EbsScript) and miscellaneus interfaces (Excel, databases, DLLs) which will be useful nce the plants are built and need supervisin and ptimizatin. With the new technlgies, there is a trend t mre and mre chemistry in the pwer plant. The questin is t what degree Ebsiln shuld be able t simulate chemical prcesses. Our basic strategy fr the develpment f Ebsiln is: the pwer plant engineer f tmrrw must be able t simulate his plant with Ebsiln nly. Therefre, Ebsiln has t include as much chemistry as is needed by pwer plant engineers. Fr the current Ebsiln release, we the fllwing cmmitments were applied: Fr chemical reactins, Ebsiln des nt cnsider the kinetics f a prcess. Ebsiln is restricted t calculate chemical equilibrium states fr the mst imprtant substances. But it is able t accept specificatins fr cmpsitins that are supplied frm external calculatins r measurements.

3 Fr material tables, it is nt reasnable t implement a large internal library fr all kinds f strange fluids. Instead, Ebsiln ffers an interface t include material tables that yu receive frm ther vendrs. 3.2 Ebsiln Cmpnents fr IGCC As an example, we set up an Ebsiln mdel fr an IGCC plant accrding t data specified frm RWE in /1/. Nte that this mdel is used just fr the demnstratin f the capabilities f Ebsiln and nt fr any real planning. Gasificatin Althugh Ebsiln includes a gasificatin mdule since the 1990 s, a new mdule is develped t cnsider different technlgies (fluidized bed as well) and t ffer mre flexibility (switch fr the usage f the water gas reactin r the specificatin f utlet cncentratin f ne f H2, CO, H2O r CO2, switches and characteristics fr the handling f CH4, NH3, H2S and benzene) and different mdes t cnsider heat lsses. Shift Reactr This mdule includes a rutine fr the calculatin f a chemical equilibrium f CH4, CO, CO2, H2, H2O, O2, C2H6, C2H2, CH3OH and slid C. Extensins n H2S and COS are planned. There are several ways t specify the equilibrium temperature, alternatively, it is pssible t replace the equilibrium calculatin by specificatin f the

4 H2, CO, H2O r CO2 utlet cncentratin. The ther substances can be handled by the equilibrium calculatin r by the specificatin f the utlet cncentratin r simply passed thrugh frm the inlet. Cal Dehumidificatin This mdule is available since It is nw extended by characteristics fr srptin isthermals and binding enthalpies. Pressure lsses in fluidized bed and the nzzle can be handled separately. Cmpressr Instead f a single characteristic line it is nw pssible t use characteristic fields fr efficiency (either istrpic r plytrpic) and pressure increase, depending n flw and a gemetrical parameter (flap psitin). Saturatr The new mdule supprts subcling and a greater flexibility in the specificatin f utlet parameters fr gas and water. 3.3 Ebsiln Macrs fr IGCC Washers and air separatin units are nt implemented as single Ebsiln cmpnents but by macrs. Macrs are cmpnents in Ebsiln that are cmpsed f several Ebsiln cmpnents with individual specificatins, results, scripting and pictures. As these macrs can be mdified by the user, it is pssible t custmize them accrding t individual requirements. Fr example, a simple macr fr a Claus Reactr lks like this:

5 If a mre detailed apprach is required, yu can d smething like this: In this cycle, methanl is calculated using the REFPROP library [2]. 3.4 Prgrammable Cmpnents in Ebsiln Due t the pen architecture f the Ebsiln sftware, it is pssible t include wn cmpnents. Yu can create cmpnent either with an external prgramming tl (creating a DLL that will be called frm the Ebsiln calculatin kernel) r yu can use EbsScript t create a script that defines the cmpnent behaviur. EbsScript is a very cnvenient way t slve tasks that extend the scpe f the Ebsiln kernel, because yu have an easy access t all quantities in the cycle. References [1] Lambertz, J.; Ewers, J; Clean Cal Pwer The respnse f pwer plant engineers t climate prtectin challenges; VGB PwerTech 5/2006, pp [2] NIST Reference Fluid Thermdynamic and Transprt Prperties Database (REFPROP), Natinal Institute f Standards and Technlgy, nist23.htm