here - Costec Systems
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1. A measurement name is a lower case 11 character string aa nn aa nn a nn where a and n indicate an alphabetic and numeric character respectively There are two schemes for decoding the name string one for measurements sourced from networks and the other for measurements sourced from non network components Each of these coding conventions is illustrated by the following examples Measurements sourced from networks ntOibrO9fO3 flow f in cell 3 of branch br 09 of network 1 ntO2br27p02 pressure p in cell 2 of branch 27 of network 2 ntOind06tOO0 temperature t in node nd 06 of network 1 ntO3bri6i03 inner metal temperature i of cell 3 of branch 16 of network 3 ntOibri6q07 inner wall heat transfer q of cell 7 of branch 16 of network 1 Measurements sourced from aggregated components Each component simulation model is written as a library procedure and returns the state and output vectors to the calling program The contents and ordering of each vector are set out for each component in the User s Reference Manual A measurement may be connected to any element of either of these vectors by encoding its reference as illustrated by the following examples The use of x in position 5 indicates the source is not a network component The next character indicates whether the source is a state s or output y model variable The first two characters identify the component type and the numeric in2. Air extraction and vacuum systems e Steam systems High intermediate and low pressure steam distributiion Auxiliary steam generation and distribution Gland sealing Steam line tracing Water steam tems Gas systems General Sys NETALYSER rev 6 02 03 Costec Systems 6 Network branches are formed as the serial interconnection of one or more components drawn from the following 3 2 Steam systems circular pipe valve located in a circular pipe expansion turbine condensing or back pressure thermo compressor tubular heat exchanger steam gas tubular heat exchanger steam fluid Q 2 systems circular pipe pressurised system rectangular duct near atmospheric system fan axial centrifugal control valve circular pipe control damper louvres in rectangular ducts tubular heat exchanger gas steam tubular heat exchanger gas gas tubular heat exchanger gas fluid gas turbine Hydraulic systems circular pipe valve centrifugal pump fin fan cooler shell tube heat exchanger fluid fluid tubular heat exchanger fluid gas tubular heat exchanger fluid steam Aggregated components Aggregated components are complex stand alone equipment to which the networks connect and which serve to define the external boundary conditions of those networks They include drum boiler dual fuel firing with without integrated superheater waste heat recovery boiler direct contact heater evaporator deaer
3. may toggle the computation sequence between its RUN and FREEZE modes In RUN mode the computation will continue to iterate indefinitely In FREEZE mode the computation sequence is suspended and will be resumed upon reselection of RUN mode The user can cause the execution of a single step STEP mode of the computation sequence for step by step examination of the evolution of the event under study The state of the simulation computation that is the values of all State and Input variables may be saved for later use as an initialisation state The NETALYSER system provides an Initial Condition management facility for the storage and subsequent recovery of an initialisation state It is the user s responsibility to assign meaningful names to and to back up these files Any file so saved can be used as the initial state for subsequent analysis Physically based models need ex tensive plant data Relative import ance of some elements of plant data Example tubular heat exchanger NETALYSER rev 6 02 03 Costec Systems 17 9 Plant Data Requirements The process models used by NETALYSER are derived by the systematic application of mass en ergy and momentum balances and by the use of established engineering formulae for pressure loss and heat transfer coefficients With the exception of a small number of empirical constants intro duced to account for imponderables in the characterisation of process plant all model coefficients are expresse
4. of measurements and their connection points automatic control loop functional diagrams design of a graphical user interface GUI and its linkage to the plant A database table of pre defined format is used to present each of these items to the NETALYSER computation engine The bulk of the simulation is therefore configured by the user by the completion of a set of database tables with no writing of computer code The core of the NETALYSER system is its high speed computation engine Specifically devel oped for this application it is an advanced algorithm which automatically builds and then solves the network system matrix equations which describe the complex time varying and spatially dis tributed behaviour of the complete network Unlike other simulation methods which build up a complex system by the user s interconnection of discrete plant components NETALYSER builds a set of matrix equations directly from the network topology information and plant data set up by the user Spatially distributed effects one dimensional in the direction of flow are included by the representation of each network element as a contiguous set of control volumes or cells Two coupled matrix equations are formed one solving for the pressure flow distribution and one for the enthalpy temperature distribution simultaneously at all points cells throughout the network The coefficients of the two matrix equations and each interfacing component are com puted direc
5. 0NB Sm i Ignitors 1 3 Fuel Gas Supply Atmosphere fan01 mtr02 duc12 dpr01 duc13 nar 22m 10m 22m 10m gt Fumace 1 duc14 ducts Furnace 2 47 2x2m 10m gt 2x2m 10m 48 duci6 bate duc17 Furnace fan02 mtr03 2x2m 10m s 2x2m 10m fan03 mtrO4 duct1 dpr04 duc18 69 Fam 10 ma t eee Combustion Air Supply duc24 Hot air TUXO1 Tux TUX 2x2m consumer z 450 deni baia duc02 ue M NNI Umaga 4x4m 10m EE O 4x4m peu 4x4m tiana Superhoaters Sm 10m Air Heaters duco3 TUX02 TUX06 duco4 TUX10 duc20 51 u U U Furnace 2 ax4m 10m Hemd nS T D xam Atmosphere Economisers 10m ia x m TUX03 TWO og TUX11 T 52 u duc21 Atmosphere Furnace 3 Taxam 10m E SEN axam Be 4x4m ph pal bai Air Heaters TUX04 TUX08 duct l 53 u u duc22 Atmosphere Fumace 4 4x4m 10m Ni HE 4x4m SEE 4x4m P 5m 10m Flue Gas System y e duc23 Legend fan04 tb03 w 2x2m Air Blower System 12 internal branch index 30m pip23 intemal component code ID eq fan05 trb04 pipe 23 as used by data base 167 N duces x control valve J 30m Costec Systems Pty Ltd 1 Avon Street Bulamakanka Minerals Ltd DA valve with NRV direction gt Minerals Processing Div Power Department NB length ombustion Air Flue Gas an el Ga i b o 3 as and as Systems te Australia internal network node index Simulation Scope Schematic Date WWw costecsystems com 300NB 100m pipe dimensions Pro
6. NETALYSER rev 6 02 03 Costec Systems 1 NETALYSER A Process Utility Dynamic Analysis System The process analysis system NETALYSER is the in house simulation system developed and used by Costec Systems for the dynamic analysis of power generation and process plant utility systems It has been designed for the simulation of the transient behaviour of complex steam gas and hydraulic networks and their associated peripheral systems such as steam and gas generators gas holders deaerators tanks etc This document has been prepared for the information of clients of Costec Systems in order to acquaint them with the scope methods usage and utility of the NETALYSER system It is not a User Manual The system includes a user configurable fully featured interactive GUI for the on line control of the simulated plant This can be displayed on one or up to four screens depending on the selection of video graphics card The basic system can be configured and used with no links to any external controls However the system supports a TCP IP interface link to an external SCADA or process control system The process simulation configuration may therefore be separated from the user interface and plant controls each which may be implemented on an external but coupled unit Costec Systems Pty Ltd ENGINEERING CONSULTANTS 1 Avon St Cammeray NSW 2062 Australia Tel 61 02 9929 8885 Mobile 61 0 412 176 710 Fax 61 02 9929 8885 Email pok costecsy
7. a processing purposes In simulation terms in which only models exist outputs are quantities derived from states and inputs They are used to link models by providing the inputs needed by other models downstream in the execution sequence They may be sent to peripheral processing systems such as the plant data processing computer Outputs are related to their source variables via algebraic equations or decision variables They do not have internal states of their own Inputs Again in conventional process control terms process inputs are either actuation com mands given to the positioning actuators of the various control devices of the plant valves pumps dampers etc or are the defining parameters of material and other flows entering the process In simulation terms the outputs and inputs define the set of matching quantities via which individual models communicate with each other or which define the boundary conditions of the process In most cases but not always one model s output array provides elements of the input arrays of one or more other models NETALYSER rev 6 02 03 Costec Systems 12 Data encompasses the numerical values of all of the coefficients of the equations the model will use It usually comes in two flavours i static data which once calculated does not change as the process evolves and ii dynamic data which is recalculated and updated either every computation cycle or period ically as conditions elsewher
8. ain along the branch and may be within another component such as a heat exchanger The user is required to specify the index of the cell to which the side flow connects and the thermodynamic conditions at the other end Alternatively the other end can be connected to a specific connection stub on an aggregated component such as a tank to a specific node in a network or to atmosphere 3 7 Linkage of networks to aggregated components Network branches connect to peripheral aggregated components at pre defined connection stubs A stub is associated with a unique index which identifies the specific point of contact to the component Any number of branches can connect to a given stub The various stubs and their associated indices are summarised by the following table Lumped and dis tributed evaporator models NETALYSER rev 6 02 03 Costec Systems 9 Component Stub Index Connects to Tank en gas space liquid space Drum outgoing steam line feedwater inflow drum water drum steam space Condenser steam space hotwell air extraction Feedwater heater bled steam drain outflow cascade drain inflow shell steam space Deaerator bled steam support steam condensate inflow cascade drain 1 inflow cascade drain 2 inflow common drain outflow feedwater outflow water space Furnace gas recirculation secondary air supplementary air flue gas fuel oil fuel gas Burner furnace index burner mill primary air index 3 8 Fire
9. ator water cooled condenser gas turbine fixed volumetric flow source e gas holder e gas burner or burner register e atmosphere e tank cylindrical vertical horizontal open enclosed This selection of components and devices is adequate for most applications New elements e g fluidized bed once through and fuming furnaces evaporators may be added to suit specific requirements Network compo nents steam and gas tur bines drum boilers waste heat recovery boiler tanks deaerator gas holder Lags in tempera ture measurements Thermocouple pocket dynamics NETALYSER rev 6 02 03 Costec Systems T 3 3 Measurements Measurements available for connection to any network cell see section 4 2 or peripheral com ponents include but are not limited to pressure of the working medium temperature of the working medium mass or volumetric flow of the working medium inner and outer temperatures of the metal containing wall generated electric power MW e gas turbine exhaust and other air gas temperatures selected metal temperatures drum water level individual downcomer and riser metal temperatures drum water enthalpy and temperature drum pressure drum saturation steam temperature riser heat absorption and heat distribution upper and lower drum metal temperatures e as for a drum boiler fluid level temperature of fluid and gas pressure in the gas vapour space pressure at the lower connec
10. buted sometimes over considerable distances Their dynamic simu lation must be capable of reproducing the relevant consequences of this spatial extension Com ponents are generally not spatially distributed although in some cases the accurate reproduction of their internal processes needs spatial effects to be considered Networks are ephemeral and come into existence only as required by a specific application There are no libraries of networks Typically networks are built up as the interconnection of simple components into branches Individual networks are joined together by connection to complex components at their external nodes or interfacing points The aggregated components are frequently elements featuring significant mass or energy storage As such they serve as stable sources of boundary conditions for the more fragile networks which typically feature small volumes coupled non linearities and rapid transients the right ingredients for numerical stability problems Most process plant sub systems can be considered as networks for simulation purposes Systems which lend themselves to treatment as networks are summarised in the following list e Hydraulic systems e Feedwater e Condensate recirculation e Bearing lubrication e Power oil circuits e Condenser cooling water e Miscellaneous cooling water systems e Air and gas systems Compressed air Furnace combustion air primary secondary and tertiary Flue and exhaust gas
11. c Systems rev 6 02 03 NETALYSER Process Plant Feedwater Supply System with Economisers WOO Suiajs sa28 S00 AWM anewayas adoos uogejnuiis eijensny k Jajyempa94 19109 Z907 MSN Aelawweg jeans UOAY pr1 Aid swajsAg 791907 Aig Bursssoog sjeu p11 sje1eury eyueyewejng OEA co wor aNooz laz aNOOZI fo ang goa NO LDS L INN f gel zi T j Le woe uoi goo o lunz SNO pede uoo e aay codd vodid egdid a N9PON goxm BZMA S aS ti E gadid 10 Jal anoozi woz GNOOZ pay C eee som gza SJ8siulOuO23 a ws AN00ZI p lec ic 9sdd 9ZNI 9094 oduid zl ggdid S dung pes 1d4S S0qn zodwd 3 1gdid wor SNOOZ 04 SNOO Lonw Loduid dung 5 Z AeidsHSQ peesjounem MA 2 Luwopie uot SNO01 Sopou Wa sAs wea s wog aNoozi wot anootl X PU epou Jomeu euJe ur ui6us gN sugsu wp edid w00 AN00E lt UOn28JIp AYN UUM anjeA P4 BAIGA JONUOD x aseq ejep Aq pasn se cz adid 6a g apos jueuodwoo ewayul ezdid x pu youe jewayu 21 puobo NETALYSER rev 6 02 03 Costec Systems Process Plant Fuel Gas Combustion Air and Flue Gas System Schematic Regulated Gas Source 200 p Furnace 1 40 20NB 100m 20NB 5m n Ignitors 1 3 vlv21 par pip78 pip79 Furnace 2 20NB 100m 20NB 5m lanitors 1 3 viv22 42 pip80 pip81 Furnace 3 20NB 100m 20NB 5mj i Ignitors 1 3 viv23 43 pip82 pip83 A Fumace 4 20NB 100m 2
12. c recording of a log of all configured measurements Each measurement is sampled at a default rate of two seconds and stored to disk at regular intervals 5 minutes in a text file format suitable for the off line production of high quality charts Selection of dis crete time step FREEZE RUN se lection SAVE and LOAD functions NETALYSER rev 6 02 03 Costec Systems 16 8 Simulation Control and Initialisation Facilities A computation procedure designed to yield information on a steady state condition results in the production of a single perhaps large set of data A procedure designed to yield information on dynamic transient behaviour will result in a series of perhaps large sets of data which define the future evolution of a set of process variables Successive data sets are separated in time by the discrete time step selected by the user to match the expected transient characteristics of the process under study For process plant this is typically in the range 0 25 to 5 seconds though accurate reproduction of control system behaviour during fast transients will usually impose an upper limit of 1 second The NETALYSER system utilises a number of internal timers for computation and display sequencing Internal computations are executed with a user selectable fixed time duration Its default value of 50 milliseconds ensures a high degree of dynamic accuracy even for fast transients GUI displays are updated every second The user
13. cPlnt Cammeray NSW 2062 NETALYSER rev 6 02 03 Costec Systems Process Plant User Configured Control GUI with Real Time Trending a 100 20 300 400 do LP System Pressure pos Mc goo as w E Before e Gen Power IG 2 R kw Bat Flow Br 2 PLA 29m T 342 deg C 8 a E Drum Pressure Bir 4 NE sc Drm Sat Temp Bir 4 NE sc SH Sim Temp Bir 4 Funsce Ex T fk 4544 0 dec C EH r Drum Pressure Bn 2 NE aeo c Crm Sar Temp kI gon Es T fe 320 1 deg C weace Quel KW ao Fun EE Orum Pressure Bir 2 BEA ic Drm Sat Temp Bk 2 IFaace Qiel Kw 00 RH ieo c Dim 861 Temp Bp L dey c SH Stm Temp Bir 1 Drum Level Br 1 4410 rem Per l i 300 We Ekpradiman 17 15 24 25 Costec Systems rev 6 02 03 NETALYSER Process Plant Simulated Trip of One of Four Boilers with Recovery Measures URZ B8L adng WU 000 1 Azp uoo pag woy moj wg on OSE LYZ eng 19 dw yes wa 0 00 Olrich PPP GAS UU o igo edy OPSEEE usen 008 2 Pit wr 0597 gE zPOIS eA L Lig dus was HS Orr PL uoo L 1 9 Woy oj wS osoez nid Lyg due je5 wig USSC Peu
14. d and heat recovery evaporators The dynamic behaviour of the evaporator is frequently a dominant influence on the start up and manoeuvring dynamics of power and steam generating plant This can apply to both fired and heat recovery boilers For some cases for which the principal interest is in the behaviour of the steam system itself a simple generic boiler module can provide simulation of sufficient accuracy This module is an implementation of the model described by Astrom and Bell For applications requiring more detailed information on the behaviour of the boiler plant itself such as those looking at the dynamic interactions between fuel supply furnace heat release and distribution steam generation rates and steam pressure and temperature controls a more detailed module is available This is a 10 cell one dimensional in the direction of flow distributed model of the evaporator which may be configured either as a loop consisting of interconnected modules for the drum hydraulic circuit downcomer pipes assisted circulation pumps header drains and two phase riser or as a Benson once through boiler configuration Flow conditions in the hydraulic sections of the loop are treated as incompressible and homo geneous Note that this does not preclude the treatment of steam entrainment from the drum into the downcomer a condition which creates a small steam phase at the riser inlet The state of the working fluid in the riser can change from wat
15. d in terms of basic plant arrangement and physical design data While this approach yields high accuracy and reliability of the computation results and makes possible the prediction of plant behaviour on the basis of design information only it creates the need for the identification and entry of considerable basic plant data This is less onerous than may at first appear as much of the plant data relates to material properties and arrangement factors for which standard Handbook figures can be used and which will be approximately the same for all like components in a given plant The completion of plant data tables can therefore be greatly accelerated by the judicious use of the table editing facilities Not all data items are equally important and their accuracy can be matched to the principal results expected from individual investigations For example if the principal interest is pres sure flow behaviour the extensive data relating to enthalpy temperature distribution may be estimated and sensitivity checks made to demonstrate the absence of any adverse effect on pres sure behaviour which may arise because of the coupling between the two equation systems The reverse will not apply as accurate prediction of enthalpy temperature behaviour will presuppose accurate prediction of pressure flow behaviour An indication of detailed data requirements is given by the following comprehensive list of data for a tubular heat exchanger enclosed in a gas d
16. dex after the xs or xy identify the specific component Finally the last three characters identify the specific variable or measurement l hese are illustrated by the following examples drO3xs05tO01 upper metal temperature state 5 of drum dr 3 rs02xs06t05 fluid temperature state 6 of the 5th cell of 10 of the riser of boiler 2 da03xy04p01 pressure at the bottom takeoff point output 4 of deaerator da 3 fh03xs01p01 body pressure state 1 of feedwater heater fh 3 tki4xs01003 pressure in the gas space state 1 of tank tk 14 st39xy00W01 total power kW developed in steam turbines 3 to 9 This coding system gives the user access to every state and output variable within the scope of simulation regardless of how many The measurement database is constructed as a simple database table as part of the simulation configuration This database includes specification of GUI display location and trend recording assignments scaling and offset of displayed variables and other information NETALYSER rev 6 02 03 Costec Systems 20 11 Project Management It is assumed that in an engineering office environment more than one project will be under investigation or development at any one time NETALYSER provides facilities for the definition and management of several simulation projects on the one PC The system will automatically create and group into project specific directories all data files tables ICs and measur
17. e within the simulation change Static data is largely derived from the physical design parameters of the plant sizes geometries fixed characteristics environmental parameters etc Dynamic data is largely derived from changing process conditions such as the physical properties of materials and of the working media composition of the working media heat exchange coefficients and friction factors which depend on thermodynamic and flow states tank levels which depend on tank geometries pump head flow relationships which depend on speed etc These dynamically varying properties and parameters are the usual sources of sometimes extreme process non linearities Material properties are computed for all working media as functions of current thermo dynamic conditions Accuracy is assured by the use of table lookups combined with efficient interpolation schemes supplemented where appropriate by high fidelity polynomial fitting func tions NETALYSER rev 6 02 03 Costec Systems 13 5 Treatment of Controls Standard actuator NETALYSER provides a standard interface to all actuators and motorized drives pumps fans for interface modulating controls and manual GUI control stations The figure shows the standard arrange ment for a control valve Valve Position Manual Actual CONTROLS index Setpoint rate Follower CL Switch CL e Valve mi OP OP Position value Direction auto m Setpoint Para
18. ement logs created for a project The system maintains a project name list from which the user can select a target project to work on 12 Example of a Set of Working Documentation A Process Energy Plant The following schematic diagrams show the extensive scope of simulation for an energy plant typical of the chemical process and mining industries The plant consists of 3 x 50 T hr plus 1 x 100 T Hr gas fired boilers 2 x 8 MW steam turbine driven electric generators and miscellaneous other plant including an additional 2 steam turbines driving blowers air compressors The HP steam pressure system is supplied by the fired boilers with pressure regulation via the gas flow rate control The LP system is supplied by the turbine exhausts and is regulated via two letdown valves from the HP system The 3 smaller boilers share a common steam turbine driven feedpump with individual drum level regulation via independent feed regulating valves The 4th boiler has an independent turbine driven feedpump and drum level regulation The system physically extends over a large site with some steam distribution pipes up to 1 km in length The NETALYSER simulation dynamically computes the thermodynamic and flow properties of the working medium steam water air gas in 128 cells throughout the connected flow networks It also dynamically computes the thermodynamic flow and mass properties of the working me dia within each of the lumped components furnaces boile
19. er only zero steam fraction prior to com mencement of boiling up to a maximum steam mass quality of 0 7 limit of validity of two phase 1 Simple Drum Boiler Models IFAC Symposium on Power Systems Modeling and Control Applications Brus sels 5 8 September 1988 Associated furnace heat release and distribution model NETALYSER rev 6 02 03 Costec Systems 10 pressure drop and heat transfer correlations Phase slip in the riser can be treated but zero slip conditions are normally assumed In the Benson boiler configuration the increase of steam mass fraction above 0 7 is accommodated by transition to burn out heat transfer and pressure drop correlations An associated linked furnace module provides point model computation of total heat release and lumped heat distribution within the furnace cavity and radiative transfer to absorbing sur faces visible beyond the cavity Using a centre of flame concept parametized empirical heat distribution profiling functions are available to distribute the heat transfer axially along the wa terwalls This profile is used by the riser module as the source of heat input to the tubes The user may set the profiling function to suit expectations or measurements of heat distribution and link the profiling parameters to other conditions of the furnace such as burner configuration and tilts NETALYSER rev 6 02 03 Costec Systems 11 4 The modelling approach 4 1 Simulation model organisation The ma
20. ev 6 02 03 Costec Systems 3 1 Overview NETALYSER is an advanced dynamic process simulation system used to quantify answers to questions of transient behaviour arising in the course of the design and operation of large power stations industrial process gas or steam systems waste heat recovery or of hydraulic networks handling such things as condensate recovery water treatment reticulation fuel oil distribution heat exchanger networks or tank farms NETALYSER is ideally suited to the systematic analysis of what if situations which can arise as a consequence of equipment malfunction altered operating procedures plant or control system modifications or unexpected or unintended external influences Detailed analysis of transient events can be undertaken with high dynamic accuracy The steady state conditions achieved at the conclusion of the transient will accurately reflect mass and energy balances throughout the plant NETALYSER is configured to operate on a standard high performance PC Windows 9x NT4 0 2000 XP It is built around a purpose designed high speed computation engine By providing easy to use facilities for initialisation computation data and graphical display and documentation NETALYSER allows the user to focus on simulation and problem solving without the need for extensive technical computing experience all within a user friendly Windows environment To reduce the time spent on problem preparation and the
21. ine display of computed values in numeric format with appropriate descriptive labels and units e the display of trend graphs which show the evolution with time of selected computed variables e labelled summary graphs covering the complete duration of the computation interval The first two displays provide information to the user on the evolution of the event and can be used to guide manual operational intervention The third is used for off line hard copy documentation of the investigation results for later scrutiny and inclusion in reports All displays are in colour A variety of devices are available for the GUI display of measured variables These include labelled numeric display windows and a number of traditional linear and rotary meters A selection of these is shown below These indicators also have the capability to alarm limit violations via a flashing display Steam Flow to Tuib 327 2 kg s 8 12 6 NN nm 14 Default Style 4 iE P RS c 2 mus 8 Deaerator Pressure mue Do Digital Value Display Drum Pressure a00 B00 Rotary Meter 270 Deg 500 ann 40 60 20 80 300 ES 200 0 100 100 100 A Crusher Motor Current TSV Temp Hot RH Temp Rotary Meter 180 Deg Vertical Linear Indicator 40 60 20 41 80 s 7 Dies 100 M 0 ZU NT B Elec Feed Pump Speed Reserve Oil Tank Rotary Meter 135 Deg Horizontal Linear Indicator The system includes a background recording facility for the automati
22. jority of process systems can be best represented mathematically by some differen tial algebraic equation system The describing equations will establish the causal relationships which exist physically among two sets of quantities inputs and outputs via a third set the internal states of the process The physical data about the process and its environment used by the model is encapsulated within a fourth set of quantities which we will notate simply as data These relationships are illustrated by the following diagram Inputs gt States Outputs Data States These are quantities whose values completely define the state of the process at any time Multiple states are grouped together into a state vector or array The time evolution of a process is described by the time evolution of its states In the usual representation of process mathematical modeling each state is associated with a single differential or difference equation through which its rate of change with respect to time and or one or more spatial variables is related to itself and other states and to the process inputs The simulation model generates the time and spatial evolution of the states moving in response to the changing inputs Outputs In conventional process control terms outputs are those quantities which can be measured or estimated They are usually produced by the plant instrumentation and are used for control operator information and general dat
23. le the primary side of a superheater bank can be in a water steam branch with its secondary side in a flue gas branch 3 5 Treatment of compressibility of the working media By setting a compressibility flag for each branch the user can direct the computation engine to treat the working medium as compressible or incompressible Branches carrying steam for example would normally be treated as compressible whereas branches carrying water and oil such as found in cooling and lubricating oil circuits would be treated as incompressible A water steam branch in which phase change is known or expected would always be treated as compressible Choice of compressibility effects only the method of calculation of pressures and flows The calculation of thermal effects and heat transfer is independent of compressibility assumptions with the exception that compression energy is ignored in an incompressible branch 3 6 Treatment of side flows The usual and recommended method for joining flow paths within a network is via an internal node at the point of intersection However in some cases such as leak flows it can be more convenient to introduce a side flow NETALYSER allows the connection of a flow path to one cell along a network branch The flow path can include a valve or damper and might be used to connect say a drain valve or steam trap to a pipe The selection of the connecting cell will usually reflect the physical location of the leak or dr
24. meters manu fixed index local This arrangement includes connections and assignments for single input single output modu lating controller loops The loop includes a standard discrete step 3 term proportional integral derivative controller whose tuning parameters are to be adjusted by the user Three operating locations are available for any actuator or motorized drive Local manual operation only drive position set directly from GUI or in response to interlock signals Remote manual operation of a drive which is not the final control element of a modulating control loop no controller action manual operation of a drive which is the final control element of a modulating control loop controller action blocked when in manual mode auto manual selector in the associated GUI module Three operating modes are available for any actuator Stepping The actuator moves a single step for each manual pushbutton operation Latched The actuator moves continuously in the selected direction until stopped by the operator or it reaches the fully open or fully closed position Trip The actuator closes at high speed reopening of the actuator requires man ual clearance of the trip signal An actuator selector to automatic mode cannot be latched A trip command will override automatic or manual commands Configuration of The user can configure any standard drive interface and its associated control loop interactively control loops by approp
25. ndex in the range 01 99 The full list of device type codes is given in the User s Reference Manual Some samples are vlv valve dpr gas damper pip pipe pmp pump cpr thermo compressor trb expansion steam turbine trg gas turbine hxc shell tube heat exchanger tux tubular heat exchanger steam gas tug tubular heat exchanger gas gas duc gas duct blr fired boiler hrb heat recovery boiler cdn water cooled steam condenser tcp thermocouple pocket The entry of pip42 for example into a network configuration table indicates to the configu ration builder that the indicated position in the network branch is a pipe and that the data to be used in building the network matrix equations is that listed for the 42nd element in the pipe database With the exception of some heat exchangers all device codes are entered into the configuration tables in lower case For heat exchangers with both a primary and secondary side the secondary side assignment is indicated by the use of upper case Signal codes used to link measure ments to sources and users Measurement nam ing conventions NETALYSER rev 6 02 03 Costec Systems 19 10 2 Measurements In order to be available for GUI display or as an input to a control system a raw computed variable must be assigned and thereby linked to a measurement name This name is used by the system to create the link between the source variable and the internal user
26. ntrol and data display modules organized into a pre sized arrangement of rows and columns The GUI is configured by entry of display module screen coordinates and display texts in the configuration tables for measurements actuators and controls Functions implemented via the GUI include adjustment of a fixed setpoint adjustment of a valve damper position motor start stop trip valve damper trip closed status change toggle on off or open close of any discrete state device selection of one of a set of alternatives digital status display numeric measurement value display trend graph display All displays are labelled with a user defined text Each GUI module displays process information relevant to the device e for a valve or damper o mass flow through the device o differential pressure across the device o stem or shaft position e for a motor drive o mass flow through the device o differential pressure across the device o speed in rpm For a controlled valve or damper the GUI module is labelled with the signal code name of the controlled measurement The GUI module displays e the numeric value of the controlled measurement e the deviation from setpoint e the position of the controlled actuator NETALYSER rev 6 02 03 Costec Systems 15 7 Display and Recording of Results Facilities for the display and recording of computation results have been integrated into the NETALYSER system to provide for e the on l
27. r evaporators and drums deaerator condensers etc and the work done by the individual rotating components steam turbines com pressors and pumps The entire system is recalculated in real time each 50 milliseconds as the dynamic events evolve Also shown are a screen print of the user configured interactive GUI used to control this plant during simulation testing and a sample print of simulation computation results in the form of summary trend graphs showing the response of the steam system to the loss of one heavily loaded boiler followed by a combination of manual and automated response measures 21 Costec Systems rev 6 02 03 NETALYSER Process Plant Main Steam System Schematic ND Bursseoo1d Sesau p11 Sj amp 1eury exuexeuireing woor qNOOc ELdid ueg dung pee asg Sa iog nys VENI nus 119 zn oxm zoxm sodid c odid z lena wap jo Joquoo BAIEA Bunejn6a paa Jajioq cong zug Jenpiupuj woz anoact xepui apou NOS Ieue e bust an suotsuawuip edid w00 ANODE SAMIRA 0 ju00 x aseq gep Aq pasn se gz adid Ba q apoo jueuodwoo jewayu gzdid x pul uoueaq jeuejur 121 OO ME SUOD dH JO DOAN esty v cedid wed zouu asn enme ou SO E rou YUE SujeJp Joj LOJU esn Z 0S AN SUI Urep lIV L SYON ws aNosz 1zdid Icd eU woa KAD ENOOE zad wopz anoog 1 d ezdid si wot Vedd Lus 8Nosz woz ANOSI woos SNooe PLAIA 22 Coste
28. riate entries in the database configuration table The configuration of more complex control loops involving the formation of the controlled variable from multiple measurements multiple interactive or cascaded control loops or overriding or integrated logic will require the preparation of special code using the standard NETALYSER control block library Alternatively these controls may be prepared graphically using some other controls design package and linked to the standard NETALYSER framework via the TCP IP link Process monitoring and manual control Configuration of the GUI GUI functions GUI module dis plays NETALYSER rev 6 02 03 Costec Systems 14 6 Graphical User Interface GUI The Graphical User Interface is used for control of the process during the computation sequence The user is able to intervene at any time during the course of the event under study as if controlling the real plant though clearly not via the same displays and facilities which might be found in the real plant The user is guided in the choice of intervention by the time based trend and digital information displayed on the screen and can immediately observe the result of such intervention NETALYSER provides facilities for the configuration of a useful GUI The NETALYSER system includes a GUI builder for the configuration and integration of a single GUI window formed from a standard set of GUI building blocks The GUI is formed as a tiled mosaic of co
29. risk of errors during the definition and configuration phases NETALYSER eliminates the need for original code preparation Con figuration tables define the principal elements of the system under investigation The system supports several standard database packages such as Inprise Borland Paradox and Microsoft Access ensuring compatibility with a wide user base Clients can prepare their own plant data bases on their own sites using pre defined tables for direct input to the analysis system A sophisticated configuration utility converts the configuration table information into a set of internal tables used by the system to set up all requisite simulation model interconnections and database linkages The configuration utility performs extensive validity checking to ensure that the user has complied with the NETALYSER rules Errors are notified to the user via an error log and must be corrected before the simulation can be executed High speed compu tation engine is the core of the system NETALYSER rev 6 02 03 Costec Systems 4 2 Preparation for a simulation study The simulation study of a power generation or process plant using the NETALYSER system is preceded by the following e inspection and analysis of the plant leading to the production of system topology and interconnection diagrams annotated according to NETALYSER naming conventions collection and collation of the individual items of data for each plant component list and naming
30. stems com NETALYSER rev 6 02 03 Costec Systems Contents 1 Overview 2 Preparation for a simulation study 3 NETALYSER Building Blocks Sd Networks 22 24 e200 484 Xe Seve ey v3 4 ee eee Se ee EG 3 2 Aggregated components rs 3 9 Measurements 1 5 Lu REGE ENS ce dec deeds RC RUE CET ROS E Gan ee di Rs 3 4 Selection of the working medium 0 0 0 0 0000004 3 5 Treatment of compressibility of the working media 3 6 Treatment of side flows se s ius d ad a a a a R R RRR es 3 7 Linkage of networks to aggregated components cles 3 8 Fired and heat recovery evaporators ee 4 The modelling approach 4 1 Simulation model organisation 2 0 0 0 0 00020000 0000000088 5 Treatment of Controls 6 Graphical User Interface GUI 7 Display and Recording of Results 8 Simulation Control and Initialisation Facilities 9 Plant Data Requirements 10 Plant and Measurement Signal Naming Conventions I0 L Plant Components e a Xa ae RIPE RIRs do Ru hoe So 10 2 Measurements 4 2 2l a ele see Rh ss 11 Project Management 12 Example of a Set of Working Documentation A Process Energy Plant 11 11 13 14 15 16 17 18 18 19 20 20 Used for analysis of power plant and industrial process utility network transients Analysis of what if situations Stand alone Win dows application Use of database ta bles for data entry and problem con figuration NETALYSER r
31. tion stub level dependent heat transfer to from tubes immersion heating e as for a tank e gas volume e rate of change of gas volume All measurements except temperature are provided without measurement lag Two forms of thermal lag are provided for temperature measurements The first is a simple first order lag with adjustable lag time constant and is typically used for low pressure applications and direct measurement of metal temperatures If the thermal dynamics of the thermocouple pocket are felt to be significant a special thermo couple pocket model may be interposed between the raw process variable and the measurement This represents the thermocouple pocket as a three stage heat transfer path involving heat ex changes between the working fluid pocket metal and pipe wall It reproduces the physical pressure and flow dependent measurement errors and delays Each branch has its own working medium Compressibility of the working medium in each branch NETALYSER rev 6 02 03 Costec Systems 8 3 4 Selection of the working medium A working medium must be assigned to each branch of a network Available media shown with the configuration code include at this time water steam ws air ar flue gas fg natural gas ng lubricating oil 1b light fuel oil 10 heavy fuel oil ho This permits for example the user to configure heat exchangers as links between branches having differing medium properties For examp
32. tly from the user entered plant data using sound physically based models supported by well established and documented engineering correlations for pressure loss and heat transfer coefficients together with routines for the computation of the single component transport and thermodynamic properties of the working media Each coefficient is computed as the product of two elements one which is a function only of the physical design and materials of the plant and is computed once during initialisation of the problem and one which is recomputed each computation cycle and includes the non linear process state and thermodynamic dependencies of the equation coefficients The interfacing and in the case of multiple networks interconnecting components and controls are computed on a component by component basis NETALYSER rev 6 02 03 Costec Systems 5 3 NETALYSER Building Blocks NETALYSER offers a wide set of standard building block components from which process plant simulations can be assembled Process plant utility sub systems are formed as the interconnection of e one or several piping or duct networks e a number of aggregated lumped plant components to which some network branches connect e aset of measurements derived from sensors within the network and aggregated components e aset of regulating control loops with associated protection interlocking and selection logic 3 1 Networks Networks are spatially distri
33. uct dde duct section depth dwi duct section width dL duct section length rinsul thickness of duct insulation fha tube outer surface fouling factor em tube metal specific heat lam tube metal thermal conductivity coefficient rhom tube metal density tdi tube inner diameter tdo tube outer diameter geo reference geodetic height of the heat exchanger above site datum thyr inner tube surface hydraulic roughness ntpb number of tubes per tube bundle ntbd number of tube bundles per row ntr number of tube rows tfe tube bank arrangement factor tfz tube row count correction factor for ntr 10 tL mean tube length Component codes used in plant configuration tables Typographical case convention for component codes NETALYSER rev 6 02 03 Costec Systems 18 10 Plant and Measurement Signal Naming Conventions The configuration tools available to the user with the NETALYSER system rely on the use of strictly defined component and signal naming conventions Only by the user s careful adherence to these conventions can the configuration utilities identify the type and specific index of the component to be linked or the raw computed variable to which a measurement will be linked 10 1 Plant Components Every plant component used within a network or as an interface to a network is identified by a five character code with the standard format abcnm where abc is a 3 character alphabetic device type code nm is a numeric i
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