Techno-Economic Modeling of AINABILIT T S U S Y Algal Processes with Aspen Eric H. Dunlop A. Kimi Coaldrake E NER G E T I C S S C I R T E M O N O Some Lessons Learned Pan Pacific Technologies Pty Ltd Adelaide Australia [email protected] EC ABO Algal Biomass Summit, San Diego, October 2014 1 Lesson Learned 1: M&EB • A fully converged mass and energy balance for the total SYSTEM is essential. • Without it, a model has limited use. • It can be started on a spreadsheet, but cannot finish there. ABO Algal Biomass Summit, San Diego, October 2014 2 Lesson Learned 2: Choice of Simulator • Process simulation is essential. • Using a full process simulator such as Aspen Plus is a good investment in money and time, but it is not enough. • A range of simulators is available (see next slide) but we found that AspenPlus and Comsol worked best for us. ABO Algal Biomass Summit, San Diego, October 2014 3 Lesson Learned 2: Choice of Simulator ABO Algal Biomass Summit, San Diego, October 2014 4 Lesson Learned 3: Reactive vs Proactive Simulation Excellent when the process has been decided. as needs a lot of information to be supplied. Great for a mature process. Unable to make predictions about an immature process. INPUT STREAMS DEFINED REACTOR CONFIGURATION DEFINED Provide: Pond areas Oil Production Cell density at harvesting Reaction kinetics etc etc “NORMAL” ASPEN+ OPERATION INPUT STREAMS DEFINED OUTPUT STREAMS PREDICTED GOOD FOR DEALING WITH THE PAST REACTOR CONFIGURATION PREDICTED Pond Areas predicted Productivities predicted Oil content of cell predicted Identifies oportunites for improvement Takes a lot of setting up Slow to converge OUTPUT STREAMS DEFINED “REVERSE” ASPEN+ OPERATION i.e. tell Aspen what you want and let it tell you how to get it. Typically solves 50,000 simulataneous equations (and their derivatives) so if what you ask for is unreasonable it will never converge. GOOD FOR DEALING WITH THE FUTURE Long convergence times can be a problem (3-4 hours) ABO Algal Biomass Summit, San Diego, October 2014 5 What actually happens when Aspen runs? • What happens? Each unit operation , flow stream, physical properties of each reactant, product and intermediate is run sequentially until convergence. Each possible ion species is solved for, including precipitation etc. • How many equations? A separate insight is available in the “equation oriented mode” where it can be seen that Aspen is solving 20,000 to 50,000 equations simultaneously. • What is the result? If the problem is “well-posed” i.e. the number of degrees of freedom is deliberately kept small, then the result is a rigorous imposition of a carefully designed mass and energy balance. ABO Algal Biomass Summit, San Diego, October 2014 6 Selected Results from Proactive Use of Aspen Selected Simulation Results Full recycle, no lipid loss Process operation CO2 removal Insolation (Corpus Christi, TX) Evaporation (Corpus Christi, TX) Carbon conversion to biodiesel (9 Methyl Esters) Biodiesel produced (as 9 Methyl Esters ) 7,884 1,000,000 4.2 1.27 95 46.4 2,630,450 hour/year (90 % ) tonne/year CO2 kWh/m2/day m3/hr/hc wt % tonne/hr barrel oil equivalent /yr Total Area Reaction Operation 1 Area for algae generation Reaction Operation 2 Area for oil generation 20,033 484 19,549 hc hc hc Oil productivity (based on total area) Effective oil content Genetic stability requirements -Number of generations/year (binary fision) 5.6 57% g/m2/day wt% 43.6 ABO Algal Biomass Summit, San Diego, October 2014 7 Outputs from Aspen Model The eighteen areas are: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. Process Summary Mass Balances Energy Balance (1st Law) Exergy (2nd Law) Energy Analysis of Reactor 1 Energy Analysis of Reactor 2 Effluent/Bleed, Salinity, TDS Water and Recycle The Role of Evaporation Control of Hazardous Precipitation of Inorganic Solids Summary of Input and Output Streams Photosynthetic Efficiency Preliminary Check of Process Costs Data Assembly for Flow Diagrams Flow Diagrams : (i) Carbon (ii) Water (iii) Mass (iv) Enthalpy (1st Law of Thermodynamics) (v) Exergy (2nd Law of Thermodynamics) (vi) Exergy and Lost Work (2nd Law of Thermodynamics) Establishing the Value Chain The Value of Adding Extra Glycerol Full Financial Analysis ABO Algal Biomass Summit, San Diego, October 2014 8 Carbon Flow (kg/hr) A-100 CO2 Absorber S-100 Flow Splitter CO2 distribution R-100 Reaction Operation/ Pond 1 R-200 Reaction Operation/ Pond 2 S-101 Flow Splitter Algae Purge S-102 Flow Splitter Primary Cell Separation Dissolved Air Flotation 17,979 36,166 Product S-106 38,190 R-104 35,941 S-105 36,031 S-104 S-103 S-102 S-101 23,136 54,348 54,348 54,613 R-103 73,183 73,268 R-200 4,469 R-100 48,108 S-100 34,598 A-100 52,577 Methanol 2,249 90 18,570 Purge 681 Flue Gas In 18,667 S-103 Flow Splitter Secondary Cell Separation Decanter Centrifuge R-103 Cell Lysis Ball Mill 85 S-104 Flow Splitter Debris Clarifier 265 S-105 Flow Splitter Oil-Water Separation 18,317 new R-104 Transesterification Reactor Glycerol recycle 2,024 S-106 Flow Splitter Glycerol Separation Carbon flowrate (kg/hr) ABO Algal Biomass Summit, San Diego, October 2014 9 Lesson Learned 4: This is an Energy Project -funded by the Department of Energy • Biofuels projects rely heavily on the science of energy aka thermodynamics. • Aspen and other data bases have been vastly expanded with new versions but it is never enough. • It is often necessary to calculate (because no-one has measured) ΔHformation and ΔGformation to establish heats of reaction. ΔHreaction=ΔHformation. products-ΔHformation. reactants) • If running Aspen forwards ( reactive) you mainly only need the thermodynamics of water. • If running Aspen in reverse ( proactive) then you need good data. ABO Algal Biomass Summit, San Diego, October 2014 10 Reliable Thermodynamic Data is hard to find. Not all databases are created equal. Need to establish much from 1st principles. Components and Their Properties Algae ("Nanno") OC5 OC35 OC70 TAG9 Formula C46.2859H87.9432O18.5143N3.8417S0.0787P0.0926 C47.1631H89.3564O17.9518N3.6496 S0.0748P0.0879 C52.4265H97.8357O14.5763N2.4971 S0.0511P0.0602 C58.5671H107.7282O10.6383N1.1525S0.0236P0.0278 C52.7316H96.0013O6.0000 ΔHf kJ/mol -12,907 -12,384 -9,250 -5,592 -2,030 S kJ/mol-K -6.04 -5.65 -3.32 -0.61 1.72 ΔGf kJ/mol -11,106 -10,699 -8,258 -5,411 -2,454 MW 1000.00 1000.00 1000.00 1000.00 826.12 Methyl Esters (FAME) Type Common Name Aspen Name CAS No. C14:0 C16:0 C16:1 C18:0 C18:1n9 C18:2n6 C20:4n6 C20:5n3 C22:1 Methyl myristate Methyl palmitate Methyl palmitoleate Methyl stearate Methyl oleate Methyl linoleate Methyl arachidonate Methyl eicosapentanoate Methyl erucinate METHY-01 METHY-02 METHY-05 METHY-03 METHY-04 METHY-06 METHY-07 METHY-08 METHY-09 124-10-7 112-39-0 1120-25-8 112-61-8 2462-84-2 112-63-0 2566-89-4 2734-47-6 1120-34-9 Formula C15 H30 O2 C17 H34 O2 C17 H32 O2 C19 H38 O2 C19 H36 O2 C19 H34 O2 C21 H34 O2 C21 H32 O2 C23 H44 O2 MWt 242.3975 270.4507 268.4348 298.5038 296.4879 294.4721 318.4935 316.4776 352.5943 MJ/kmol ΔHcomb -9,430.70 -10,107.00 -10,547.90 -11,962.00 -11,832.40 -11,690.10 -13,263.00 -12,659.10 -14,451.50 MJ/kmol ΔHform -759.40 -1,441.80 -674.29 -945.60 -789.27 -604.88 -1,003.00 -186.90 -887.47 MJ/kmol MJ/kmol mol file TS ΔGform available? 149 149 149 149 149 149 149 149 149 -908 -1,591 -823 -1,095 -938 -754 -1,152 -336 -1,037 NIST NIST NIST NIST NIST NIST NIST PPT NIST MJ/kmol MJ/kmol Used in this study wt% 2 36.5 37.5 2 9 3 2 7 1 100 Triglycerides Common Name Aspen Name CAS No. Trimyristin Tripalmitin Tripalmitolein Tristearin Triolein Trilinolein Triarachidonate Trieicosapentanoate Trierucin TRIMY-01 555-45-3 TRIPA-01 555-44-2 TRIPA-02 118450-52-5 TRIST-01 555-43-1 TRIOL-01 122-32-7 TRILI-01 537-40-6 TRIAR-02 23314-57-0 TRAEI-01 99660-94-3 TRIEU-01 2752-99-0 Formula C45 H86 O6 C51 H98 O6 C51 H92 O6 C57 H110 O6 C57 H104 O6 C57 H98 O6 C63 H98 O6 C63 H92 O6 C69 H128 O6 MWt 723.1925 807.3521 801.3044 891.5114 885.4637 879.4163 951.4805 945.4328 1053.7829 MJ/kmol ΔHcomb -27,643.70 -31,605.90 -31,179.20 -35,806.70 -35,099.60 -34,555.70 -39,467.70 -38,761.44 -42,802.30 MJ/kmol ΔHform -2,355.00 -2,468.70 -2,038.00 -2,344.00 -2,193.70 -1,880.10 -2,759.10 -1,890.80 -2,643.00 ABO Algal Biomass Summit, San Diego, October 2014 mol file TS ΔGform available? 370.82 413.98 410.88 457.14 454.04 450.93 500.29 484.79 540.35 -2,725.82 -2,882.68 -2,448.88 -2,801.14 -2,647.74 -2,331.03 -3,259.39 -2,375.59 -3,183.35 NIST NIST PPT NIST NIST NIST PPT CS NIST 11 Calculated Thermodynamic Properties of Algal Cells of Varying Oil Content ABO Algal Biomass Summit, San Diego, October 2014 12 Reactions with Corresponding Heats of Reaction Table 5. Reactions with Corresponding Heats of Reaction ΔH kJ/mol ΔG kJ/mol of reaction of reaction Reaction Number REACTION OPERATION 1 1 2 3 4 5 46.29 HCO3 + 3.84 NO3- + 0.079 SO4-- + 0.093 HPO4- + 46.02 H2O --> 1 Nanno + 64.05 O2 + 50.46 OH15.4286 Glycerol + 3.8417 NO3- + 0.0926 SO4-- + 0.0926 HPO4- + -->1 Nanno + 10.0502 O2 + 15.6971 H2O + 4.1842 OHDeb80 --> ALgDeb 0.0216048 NannoNew + 0.0074 NO3- 1.2708 O2 --> + 1 CO2- + 0.0017 SO4 + 0.002 HPO4- + 0.949 H2O + 0.0452 N2 0.1296292 NannoNew + 0.0444 NO3- 1.6248 O2 + 0.306 H2O --> + 1 SOLC- + 0.0102 SO4 + 0.012 HPO4- + 0.2712 N2 21,676 19,889 -3,888 -6,682 4,778 4,344 -21,676 -21,264 -1,148 -3,600 REACTION OPERATION 2 6 7 8 9 10 11 12 13 0.65 Nanno + 22.3292 HCO3- + 0.0 NO3-- + 20.4131 H2O --> 1 OC35 + 31.2653 O2 + 22.3292 OH- + 0.0 SO4- + 0.0 HPO4 + 22.3292 OH 19,126 15,710 0.3 Nanno + 44.6585 HCO3- + 40.8261 H2O --> OC70 + 62.5306 O2 + 0.0 NO3- + 0.0 SO4-- + 0.0 HPO4- + 44.6585 OH24,993 19,042 0.65 Nanno + 7.4431 Gly + +0.0 SO4-- + 0.0 HPO4- + 0.9942 H2O --> 1 OC35 + 9.3593 H2O + 5.2145 O2 + 0.0 NO31,973 1,209 0.3 Nanno + 14.88616 Gly- + 0.0 SO4-- + 0.0 HPO4 --> 1 OC70 + 18.7185 H2O + 10.4291 O2 + 0.0 NO39,132 5,487 0.95 Nanno + 0.0 HPO4- + 2.91615 H2O + 3.18989 HCO3 --> 1 OC5 + 4.4665 O2 + 0.0 SO4 + 0.0 NO3 + 3.18989 OH 2,276 1,740 0.95 Nanno + 1.063297 Gly + 0.0 SO4-- + 0.0 HPO4- -->1 OC5 + 0.7449 O2 + +1.3370 H2O+0.0 NO3234 146 4) 0.0216048 NannoNew + 0.0074 NO3- 1.2708 O2 --> + 1 CO2- + 0.0017 SO4 + 0.002 HPO4- + 0.949 H2O + 0.0452 N2 (duplicate of Reaction-21,676 -21,264 0.1296292 NannoNew + 0.0444 NO3- 1.6248 O2 + 0.306 H2O --> + 1 SOLC- + 0.0102 SO4 + 0.012 HPO4- + 0.2712 N2 (duplicate of Reaction-1,148 5) -3,600 LYSIS OPERATION 14 15 16 OC35 + 0.187970 H2O --> 0.714286 Debris + 0.206767 O2 + 0.390977 TAG 1.4 OC70 + 0.4 H2O --> 0.4 Debris + 0.3 O2 + TAG OC5 + 0.031328 H2O --> 1.285714 Debris + 0.31328 O2 + 0.065163 TAG ABO Algal Biomass Summit, San Diego, October 2014 -3,344 -1,899 -6,131 -3,083 -1,768 -4,963 13 Lesson Learned 5: Handling Complex Stoichiometry Balancing the stoichiometry of these equations is a fast route to insanity. ABO Algal Biomass Summit, San Diego, October 2014 14 Stoichiometry Generator for Balancing Fractional Reactions Table 3. Calculations using the Matrix Stoichiometry Generator Example: a OC70 +b Debris +c O2 +d H20 +e SO42-+f HPO42- → TAG9 INPUT MATRIX [A] Raw materials C H O N S P RESULT VECTOR [B] Desired product OC70 Debris O2 H2O SO42- HPO42- TAG9 58.5501 107.955 10.6368 1.1525 0.02368 0.02780 1 1.9 0.4 0.083 0.0017 0.002 0 0 2 0 0 0 0 2 1 0 0 0 0 0 4 0 1 0 0 1 4 0 0 1 63.83 116.21 7.263 0 0 0 b c d e f a SOLUTION VECTOR [X] Stoichiometric coefficients INVERSE MATRIX [A]-1 0.022389 -0.31089 0.399691 -0.91317 -1.7E-06 -6.5E-07 1.51E-21 1.01E-17 -0.25 0.5 -3.8E-19 -1.6E-19 0 0 0.5 0 0 0 -0.269 15.793 -1.420 -0.432 -0.020 -0.024 0 0 -2 0 1 0 3.5-17 -2.1E-15 -1.75 -0.50 4.3E-19 1 1.429097 -19.84379 0.091596 -0.183107 -0.00011 -4.13E-05 a b c d e f OC70 Debris O2 H2O SO4-HPO4-- [A][X]=[B] or [X]=[A]-1[B] A positive coefficient in the solution vector denotes a reactant, while a negative coefficient denotes a product. Thus the balanced equation for this example is :1.429097 OC70 +0.091596 O2 → TAG9 + 19.84379 Debris +0.183107 H2O+0.00011 SO42-+4.13E-05 HPO42- ABO Algal Biomass Summit, San Diego, October 2014 15 Total solar =-15,145 MW Reaction Operation 1 Solar -840 MW Lost Work 660 MW Reaction Operation 2 Solar -14,305 MW -54,107 MW -347 MW -57 MW ≈-140 MW -15 MW -9 MW -2 MW -12 MW The System BioDiesel Reactor -33 MW IN Make-up Water In Fluegas In Make-up NaOH Mechanical Work pumps Methanol Chemwater N, P, S Product Biodiesel 16 MW PR -54,873 MW OG R ES S Lesson Learned 6: 2nd Law and Lost Work Reactor 1 -2,139 MW W OR Work done on system Solar 1 840 MW Solar 2 14,305 MW Shaft Work 140 MW Total 15285 MW Second Law Efficiency = 500/15,285 = 3.27% Misc lossses 17MW K Availablity in -54,647 MW Availability out -54,147 MW Availablity Increase 500 MW Pipes & Pumps 15 MW Lysis 16 MW Absorber loss 149 MW Reactor R2 -38,235 MW Recycle 658 MW Bleed 969 MW 4% Photosynthetic Efficiency 3.3% Second Law Efficicncy Exergy diagram for lost work analysis Evap1 2,232 MW Evap 2 37,996 MW As this is a Second Law of Thermodynamics Analysis it needs ΔG and hence ΔS. Entropy measurements are in total disarray... if they even exist. ABO Algal Biomass Summit, San Diego, October 2014 16 Lesson Learned 7: Pipes & Pumps Get the pipes and pumps in early. This is not normal practice, but with algae processes, they consume so much energy and capex that the sooner they are identified the better. ABO Algal Biomass Summit, San Diego, October 2014 17 Pipes & Pumps in Aspen Process Flow Diagram The CO2 Absorber (Equilibium and Rate Based) COMMERCIAL IN CONFIDENCE © Pan Pacific Technologies 2012 Chapter 1.4 Setting up Aspen ABO Algal Biomass Summit, San Diego, October 2014 31 18 Gas Pipe Line Fluegas Lay out Diagram. Pipeline costs & pumping energies Urea Pipe 22 Reactor 1 Pipe 2 Coast Pipe 1A HCl Pipe 5 Bleed Pipe 19 Effluent Treatment Water recycle Seawater Makeup Pipe 3 Pipe 1C Absorber Split Pipe 24 Pipe 4 NaOH Pipe 6 Reactor 2 Pipe 21 Primary Cell Conc Secondary Cell Conc Pipe 7 Neutralisation Pipe 18 Cell Lysis Pipe 9 Pipe 23 Pipe 17 Pipe 14 BioDiesel Plant Pipe 11 Pipe 13 MeOH Pipe 15 Pipe 25 Pipe 10 Pipe 8 Debris Clarifier O/W Sep Pipe 20 Pipe 12 Pipe 16 Glycerol (OPG) 1000 m Scale ABO Algal Biomass Summit, San Diego, October 2014 19 Lesson Learned 8: Liquifaction As we move away from the “simple” systems of biodiesel and its components, we enter another difficult area. Namely the hundreds of components that form, at different temperatures and pressures, as the biomass is liquified. Multiple reaction schemes are being investigated. How to deal with that in a TEA? ABO Algal Biomass Summit, San Diego, October 2014 20 Lesson Learned 8: RGibbs • RGibbs usually overlooked. • All the others require knowledge of complex reaction stoichiometry and rate constants, none of which we usually have. • RGibbs treats all components, reactants and products, as potential products and calculates the product mix that minimizes the Gibbs Free Energy. This is what nature does anyway! But we do need the ΔH and ΔG as a function of temperature and pressure, usually calculable. “Einstein: God integrates empirically”. This must be the next best thing. ABO Algal Biomass Summit, San Diego, October 2014 21 Lesson Learned 9: Number of Organism Generations N(t)/N(0) = 2n (binary fission) ≈ 40+ generations An unexpected output from Aspen. Sets the target for the stability of genetically modified organisms that may subsequently be used. ABO Algal Biomass Summit, San Diego, October 2014 22 Lesson Learned 10:Costing Accuracy comes at a (very) high cost 1 2 3 4 5 Study/Design Probable Range of Accuracy Cost as % of Project Expenditure Preliminary Costing Design Study Preliminary Construction Estimate Definitive Estimate Detailed Estimate 30% to 50% 20% to30% 10% to 25% 5% to 15% 2% to 5% 0.05% to 0.1% 0.1% to 0.2% 0.4% to 0.8% 1% to 3% 5% to10% Lesson 10a. Beware of any TEA that does not come with error bars. ABO Algal Biomass Summit, San Diego, October 2014 23 Approach to Cost Financial Modeling Costing Model —> Financial Model Revenues & Costs—>Operating Margins Cash Flow Analysis. How many plants, what size, when on line Cost of capital, depreciation, taxation, tax shields, investment credits etc. —>Range of cash flows Financial Metrics (M)IRR, NPV etc. Taxation has the potential to add significant cost OR tax shields may allow major cost reductions ABO Algal Biomass Summit, San Diego, October 2014 24 Lesson Learned 11: All TEA “unit costs”are not the same. ESTIMATED OPERATING MARGINS ($) REVENUES Selling Price per barrel ($120) no. of new plants total number of plants % of CO2 market oil production, barrels/year % US consumption Revenue CASH FLOW ANALYSIS Estimated cost of capital, 15% PROJECT DEVELOPMENT PHASES •Development Phase •Plant Construction & Operating phase -No. of new plants -Capital cost of plant -Cost of capital -Start up costs, 5% of capital -Maintenance, 5% of capital -Working capital, 10% of capital FINANCIAL METRICS (M)IRR % -Finance Rate -Reinvest Rate 15.00% 10.0 % NPV $xxE+y 5.00% @25.00% discount rate discount rate NPV $ 1.00% .4E+11 EXPENSES -VARIABLE COSTS (VC) Raw materials cost/yr Utility costs/yr (@ 10% raw material costs) Labor costs (@ 10% raw material costs) Workman's Comp & Unemployment Tax (@10% of Labor Costs) -FIXED COSTS (FC) Supervisory/mgmt costs/yr Cost of sales (6% of actual sales) Insurance (5% of sales) Plant overhead (5% of sales) Total costs(VC+FC) OPERATING MARGIN -Salvage value, 5% of capital cost 2.00% 3.00% Plant Depreciation (straight line 25 years) 4.00% Total Operating costs 10.00% 5.00% 20.00% Net operating cash flow TAX SHIELDS; 35%tax Depreciation (25 year straight line) Investment Tax Credit (10%) taxable income TAX @ 35% total tax shield 30.00% P:E 10 Market cap. Million $ Economy of scale over over 25 years Total oil produced 1.3E+09 barrels Total costs $1.2E+x Effective cost $xx/bbl $yy/gallon ±100% AFTER TAX CASH FLOW (revenue-costs) FINANCIAL/INVESTMENT MODEL FLOWS ABO Algal Biomass Summit, San Diego, October 2014 25 Lesson Learned 12: Missing information can be found by using other simulation tools The Case for Comsol: Depth, Light Scattering & Non-steady State Models t=0 hours. mu=1.8 days-1 t=10 hours mu=3.0 days-1 Close to maximum growth rate. t=14 hours. mu=1.7 days-1 The complete inversion point. t=100 hours. mu=0.24 days-1 Almost identical with NMSU growth rate at this point mu=growth rate Note the different scales, kept here to demonstrate the concept. GROWTH RATE and its Distribution within the reactor vs Time ABO Algal Biomass Summit, San Diego, October 2014 26 Conclusions • These are very personal observations on trying to do TechnoEconomic Analyses for algal processes & don’t suit everybody. • Each lesson we learned contributes to an integrated systems approach to algal biofuel production. • When each lesson is fully implemented into a process simulation such as AspenPlus, the result is more than the sum of the parts. ABO Algal Biomass Summit, San Diego, October 2014 27 Acknowledgements The authors wish to acknowledge that this work was prepared, in part, under the auspices of the U.S. Department of Energy under :1. Contract DE-EE0003046 awarded to the National Alliance for Advanced Biofuels and Bioproducts and 2. Contract DE-EE0006316 awarded to the research project, Realization of Algae Potential. ABO Algal Biomass Summit, San Diego, October 2014 28 ABO Algal Biomass Summit, San Diego, October 2014 29
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