2000 AspenTech. All Rights Reserved. Power Plant Optimization

Transcription

1 Power Plant Optimization

2 Why Focus On Energy / Utilities? Energy is the single largest operating expense after raw materials in the process industries The best spend less than 50% on total energy cost compared to the worst. (Solomon) Deregulation has opened up new opportunities / threats Linked to CO 2 / NO X / SO X Energy costs are rising in some regions 2

3 Energy Optimization Goals Minimize Operating Costs / Maximize Profit while: Meeting electrical, steam, hydrogen and offgas demands Honoring operating/equipment constraints Honoring contract constraints Environmental concerns (NOx, CO, etc.) 3

4 Site Wide Energy System Emissions (CO2, SOx, NOx) Fuel Import/Export Power Import/Export Water Gas System e.g. H2 Fuel Energy System Water System Process A Process B Process C Process D Feed Side- Product Product Side-Product Feed Product Production System Waste Water Combined production and energy system analysis is required Interactions between energy - water and off-gas system considered Constraints from out of site bound should be considered 4

5 Utility System Operation Challenges How much electricity should I purchase, how much could I sell and at what price? Which boilers should I use and at what load should I run these boilers? What fuels should I use and how much should I purchase what contract? At what load should I run the GTG? How much steam do I need to provide today, tomorrow, next week? How does Actual compare to Plan? How is my equipment performing? When should I shut down for maintenance? Is it economic to run my steam turbine generator? What drives should I use for the BFW pump? What is the lowest operating cost? Many decisions to be made under many constraints How can we consider all aspects simultaneously? 5

6 Optimization Pyramid Open-Loop Advisory System Closed-Loop Optimization Multivariable Control Control & Automation Instrumentation 6

7 Life Cycle Energy Management 7

8 Lessons Learned Find the benefits 1. What is 1% of your energy bill? 2. What is your complexity and flexibility? 3. Can you estimate the performance of the equipment? Get the benefits 1. One time effort is not enough 2. You must deal with whatever pushes away from the optimum 3. Measurements are important 4. Automation is the key to continued benefits 8

9 Aspen Utilities Solution Overview DCS Multi-variable Predictive Control OPERATIONS TOOL Tariffs Operational Constraints Plant Demands Loop On-line Closed Optimization Lowest Cost Operation Closed Loop Optimization Load distribution Multiple objective functions On-line Open Loop Decision Making Lowest Cost Tariff scenarios Seasonal variations Changes in demand e.g. site expansion Scheme What-if Analysis Turbine/ boiler on/off decisions Tariff selection Optimize Investment options Significant changes in demands Changes in fuel supply STRATEGIC TOOL 9

10 Strategic Solution - Advisory Solution Integrated/Consistent with Operation Solution Long-term Issues Contract Selection/Negotiation Capital Investment Short-medium term issues Equipment selection optimization (on/off decisions) Maintenance Performance monitoring Optimization MILP solver with multi-period optimization capability - can include process production planning Off-line decision making / On-line decision support 10

11 Demand Forecast Do not start a new turbine Switch turbine 2 on Steam Demand T/hr 0 hours Time 48 hours Considering steam demand profile behavior into optimization 11

12 Contract Optimization Gas Demand M3/hr demands subject to incidental gas price (planned upfront) Peak Load Middle Load Base Load HUG contract value (planned up front) 8000 hr Average (determined at end of year) Gas Contract Structure Jan April July Oct Dec Time 21:00 20:00 19:00 18:00 17:00 22:00 23: Electricity Contract 0: :00 2:00 3:00 4:00 5:00 6:00 7:00 Jan. - Mar. Apr.-Jun.Sep Jul.-Aug. Oct-Dec. Electricity use [MWe] Transport boundary 25 gld/kwh 2.5 gld/kwh Base load Peak load Middle load 16:00 15:00 14:00 13:00 12:00 11:00 10:00 9:00 8:00 Elect. Contract Structure Chronological year 12

13 Contract optimization Gas M3/hr Jan Site wide gas and electricity demands Elect MWe Dec Jan Past Profile Optimized Profile Dec Gas & elect. bill for selected contract Iterations (new tariff constants) N-1 and equipment operational constraints Alternative fuel availability Utilities Optimizer Steam T/hr Gas M3/hr Elect. MWe Jan Dec Jan One profile for each header Dec Jan Consumer gas & electricity requirement Dec 13

14 Operations Solution Closed Loop Tightly Integrated Package Advanced Process Control - DMCplus Real Time Optimization AspenPlus Optimizer Proven Reliability Integrated Goals Tie line control Constraint handling Boiler, turbine load allocation Performance Monitoring 14

15 Operations Closed Loop AspenPlus Optimizer calculates optimal operation for current state of process utilizing a rigorous model of process Buy/Sell (within constraints) Turbine/boiler loading DMCplus implements optimization targets and handles constraints and changes in demands and process between optimization solutions 15

16 When Do You Need RTO? High degree of non-linearity. Can be fundamentally modeled. Frequent disturbances. Correct time scale. Changing economics and plant constraints. Significant degrees of freedom with substantial benefits. Sufficient application scope. 16

17 AspenPlus Optimizer Closed Loop Real Time Optimization Based on fundamental non-linear models Frequent optimization cycles Model calibrated to plant each run (parameters updated) Uses current economics and constraints Cycle times of ~5 minutes Handles complex Constraints Handles tier pricing Consistency with APC and Strategic Model Facilitates performance monitoring 17

18 Closed Loop Optimization Sequence Selected Plant Measurements PLANT STEADY? NO WAIT Full Plant Measurements MEASUREMENT VALIDATION PARAMETER CALCULATIONS 1 MINUTE Controller Limits Control and Opt. Status Info OPTIMIZATION CALCULATIONS 1 MINUTE Prices Selected Plant Measurements & Controller Limits PLANT STEADY? NO IMPLEMENT OPT. SETPOINTS LINE-OUT PERIOD 18

19 Closed Loop Optimization Benefits Unit Profitabilify ($) actual unit profit potential unit profit RTO Implementations major disturbance/ price change Time (Minutes) 19

20 Analysis & Management of Boiler Fouling Fouling in Economizer 410 Outage of Plant /7/1 1999/7/ /7/ /8/ /8/ /9/9 1999/9/ /10/7 1999/10/ /11/4 1999/11/ /12/2 1999/12/ /12/ /1/ /1/ /2/ /2/ /3/9 2000/3/23 Fouling Factor [m2hc/kcal] Outlet Temp. of Exhast Gas [C] Temp. of Exhaust Gas Fouling of 1 st Super heater Fouling of 2 nd /3 rd Super heater 270 ボイラー汚れ係数 1m 2hC /kcal ボイラー汚れ係数 2m 2hC /kcal ボイラー汚れ係数 3m 2hC /kcal ボイラー排ガス温度 C -Strong correlations between Boiler Fouling and Outlet Temp. of Exhaust Gas - Assumed the fouling was removed by Thermal shock at the outage of Plant

21 DMCplus Dynamic multivariable control Moves multiple variables simultaneously Controls multiple variables simultaneously Operates at a scheduled high frequency Typically 15 sec. in utilities plant Reduces variability in key variables Honors constraints Automatically handles reconfiguration of equipment and control system 21

22 Benefits of DMCplus Operating Region Steam Demands APC Economic Optimum Reserve Requirements Power Demand Operator's Preferred Operating Region Temperatures Condensate Supply Equipment Constraints 22

23 Power Generation [MWH/H] Upper Limits Control Start??? Power Generation???? Exhaust Steam Flowrate time [min.] Exhaust Steam Flowrate [T/H] 23

24 Aspen Utilities Growing Customer Base 2000 Irving Oil, Newfoundland Huntsman, Texas BP Chemicals, Hull EniPower 2002 (2 sites - Italy ) DSM, Geleen (Netherlands) 1998 BP Chemicals Belgium JSR, Japan 2001 Celanese (6 sites - WW) BP Texas City Samsung, Korea Titan, Malaysia 1999 GE Plastics (5 sites - WW) Cepsa,, Spain Sasol, Sasolburg BP Bulwer Island, Australia Workshop Implementation 24

25 Utilities Management & Optimization Benefits Significant benefits possible 1.5-5% reduction in site-wide energy bill Provides a consistent approach for all the utilities related management and operations issues Consistent decision making from contracts to operation AspenTech Approach Systematic project approach - Energy Workshop Software Technology Transfer Complete Solution Project Services + + = 25

26 Optimization Pyramid Open-Loop Advisory System Closed-Loop Optimization Multivariable Control Control & Automation Instrumentation 26

27 CONTROL CLOSED-LOOP OPTIMIZATION STRATEGIC DECISIONS To be successful you need to do all aspects well!! 27

28 Thank You AspenTech is the World Leader in APC & Optimization Other 18.9 % Polymers Air Separation Specialty Chem Power Business Breakdown Refining 48.6 % Clients Include: Most Major Oil Companies Most Major Chemical Companies Most Major Olefins Producers More than 1,000 successful projects More than 300 full plant online optimization applications Olefins 32.5 % PROVEN integration with all leading DCS platforms including: Yokogawa, Bailey, Foxboro, ABB, Honeywell, Fisher-Rosemount 28