Biomass and Natural Gas to Liquid Transportation Fuels (BGTL): Process Synthesis, Global Optimization, and Topology Analysis
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Biomass and Natural Gas to Liquid Transportation Fuels (BGTL): Process Synthesis, Global Optimization, and Topology Analysis Christodoulos A. Floudas Department of Chemical and Biological Engineering Princeton University Natural Gas and Biomass Natural Gas Biomass • Abundant supply in the United States • Prices more stable • Low prices than natural gas • Utilization of stranded • Reduce greenhouse gas reducesA hybrid biomassgas and emissions in the environmental life cycle analysis damage natural gas energy system can bring synergistic outcomes. Ensuring sustainability of . High fluctuation of prices production over long horizon BGTL Important Questions Q1: Can we produce liquid transportation fuels (gasoline, diesel, kerosene) using only biomass and natural gas? Q2: Can we address Q1 with a 50% reduction in lifecycle greenhouse gas emissions? Q3: Can we address Q1 and Q2 without disturbing the food chain? Q4: Can Q1, Q2, and Q3 be addressed at competitive prices compared to petroleum? Q5: Can we develop a framework for a single BGTL plant that considers (i) multiple natural gas conversion pathways, (ii) any plant capacity, and (iii) any product combination? Conceptual Design Feed biomass and natural gas to produce gasoline, diesel, and kerosene via a synthesis gas (syngas) intermediate Syngas is converted to liquid hydrocarbons via Fischer-Tropsch, MTG, or MTOD CO2 can either be vented, sequestered, or consumed/recycled via the water-gas-shift reaction Simultaneous heat, power, and water integration included during synthesis Develop input-output mathematical models for each unit in the refinery Baliban, R. C., Elia, J. A., Floudas, C. A., Biomass and Natural Gas to Liquid Transportation Fuels: Process Synthesis, Global optimization, and Topological Analysis, Ind. Eng. Chem. Res., 52, 3381-3406, 2013. Process Synthesis Strategy Unit Operation Feedstock / Process Unit Cost Input-Output Product / Superstructure Functions Models Byproduct Costs Process Synthesis Mathematical Model Economic Analysis Incorporated in Process Optimal Process Topology Synthesis Model [1] Baliban, R. C., Elia, J. A., Floudas, C. A., Comp. Heat Exchanger Chem. Eng., 35, 1647-1690, 2011. [2] Baliban, R. C., Elia, J. A., Floudas, C. A., Comp. Network Chem. Eng., 37, 297-327, 2011. Superstructure [3] Baliban, R. C., Elia, J. A., Misener, R., Floudas C. A., Comp. Chem. Eng., 42, 64-86, 2012. Add Heat [4] Baliban, R. C., Elia, J. A., Weekman, V. W., Floudas, C. A., Comp. Chem. Eng., 47, 29-56, 2012. Exchanger [5] Baliban, R. C., Elia, J. A., Floudas, C. A., AIChE J., Investment 59, 505-531, 2013. Costs [6] Baliban, R. C., Elia, J. A., Floudas, C. A., Ind. Eng. Chem. Res., 52, 3381-3406, 2013. [7] Baliban, R. C., Elia, J. A., Floudas, C. A., Energy Env. Break Even Oil Price Sci., 6, 267-287, 2013. BGTL Process: Biomass and Natural Gas to Liquids Biomass Ash / Hydrogen Oxygen Vent Biomass Syngas Sand Sulfur Generation Syngas Treatment Acid Gas Oxygen Raw Syngas Steam Clean Sour Syngas Water Recycle Natural Hydrocarbon Gases Gas Natural Gas Production Conversion Methanol Hydrogen Olefins Steam Vent Oxygen Hydrogen Organic Liquid Steam Electricity Product Upgrading Oxygen and Heat, Power, Butane Hydrogen Water Integration Production Oxygen Gasoline Diesel Kerosene Propane Air Water Boiler Feed Water Water Feedstocks and Process Inputs Process Outputs Biomass Syngas Generation Oxygen Steam Biomass Output Ash Gasifier1 Input CO2 Biomass Oxygen Biomass Biomass Dryer Lockhopper Biomass Gasifier with Hydrogen Recycle1 Output Ash CO2 Steam PSA Offgas Reformed Gases Biomass Syngas to reverse 2 Tar Cracker water-gas-shift Biomass Syngas to bypass reverse water-gas-shift [1] Baliban, R. C., J. A. Elia, and C. A. Floudas, I&ECR, 2010: 49(16), 7343. [2] Spath, P et al., NREL, 2005, TP-510-37408. Natural Gas Conversion Steam Steam ATR Reformed Auto Thermal Gases Reformer1 SMR Reformed Recycle Natural Steam Reformer2 Gases Gas Oxygen SPNG POM Raw Partial Oxidation to Methanol SULGRD Methanol Mixture Sulfur Guard Oxygen Olefins OCO-F INNG OCO-CO Water Knock 2 Input Natural OCO CO Removal Out 2 Gas Oxidative Coupling to Olefins Catalyst CO Natural Gas for Wastewater 2 Utility Generation OCO-CAT IN AIR Catalyst Flue Gas Input Air Reoxidation Syngas Cleaning and CO2 Recovery Reformed gases Recycle CO Oxygen Forward / 2 Reverse Water Gas OUT Shift CO2 CO Recycle Sequestered CO 2 2 Comp. Hydrogen Biomass Oxygen syngas Reformed CO2 Seq. Comp. gases Sour Forward / OUTV Reverse Water Outlet Vent Gas Shift Recovered Hydrogen Reformed CO2 Recovered gases CO2 Sulfur SCRUB Sour Syngas Acid Gas Scrubber Biomass Removal syngas Sulfur-rich System Wastewater acid syngas Syngas Flash Clean Gas Sulfur-free acid syngas Wastewater Dry Syngas [1] Kreutz, T.G., E.D. Larson, G. Liu, R.H. Williams, 25th Pittsburgh Coal Conference, 2008. [2] NETL, 2010, DOE/NETL-2010/1397. Hydrocarbon Production Purpose of process units Convert synthesis gas to raw hydrocarbon product Remove aqueous phase and oxygenated species from raw hydrocarbon effluent Key topological decisions Hydrocarbons generated via methanol conversion or Fischer-Tropsch synthesis Methanol to Gasoline (MTG) or Methanol to Olefins and Diesel (MTOD) Fischer-Tropsch catalyst: Cobalt/Iron Low-wax/high-wax Fischer-Tropsch Fischer-Tropsch Units Catalyst type Cobalt (no water-gas-shift reaction) Iron (water-gas-shift reaction) Forward water-gas-shift (fWGS) Reverse water-gas-shift (rWGS) Temperature o High-temperature (HT - 320 C) o Mid-temperature (MT - 267 C) o Low-temperature (LT - 240 C) Wax production Minimal (Min-Wax: for maximum gasoline) Nominal (Nom-Wax: to increase diesel) Fischer-Tropsch Production Clean Gas Hydrogen Hydrogen Cobalt LT Nom- Steam Steam Wax FT3 Iron MT fWGS Iron-MT fWGS Cobalt HT Min- Min-Wax FT2 Nom-Wax FT1 Wax FT3 Wax CO2 Hydrogen Hydrogen PSA Offgas Iron HT rWGS Hydrocarbons CO Min-Wax FT3 2 Reformed Gases PSA Offgas Hydrogen Iron LT rWGS Reformed Gases Nom-Wax FT3 FT Hydrocarbons Hydrogen Wax FT FT Hydrocarbons Hydrocarbons [1] Kuo, J. C. W., Aditya, S. K., Bergquist, P. M., Di Mattio, A. J., Di Sanzo, F. P., Di Teresi, E., Green, L. A., Gupte, K. M., Jagota, A. K., Kyan, C. P., Leib, T. M., Melconian, M. G., Schreiner, M., Smith, J., Taylor, J. A., Warner, J. P., Wong, W. K., Mobil Research and Development, DOE/PC/30022-10, 1983. [2] Kuo, J. C. W. et al., Mobil Research and Development, DOE/PC/60019-9, 1985. [3] Dry, M. E., Catalysis Today, 2002: 71(3-4), 227. Hydrocarbon Upgrading Purpose of process units Convert raw hydrocarbon product to final liquid fuels Recover light gases for treatment Key topological decisions Upgrading of Fischer-Tropsch product ZSM5 upgrading Standard upgrading Recycle of light gases Gas turbine Fuel combustor Natural gas conversion Simultaneous Heat/Power Recovery Incorporate heat engines with distinct operating conditions into the system to simultaneously minimize the hot/cold utilities and the recovered electricity Lower amounts of utilities and recovered electricity reduce the overall cost of the process increased profitability To Pump (b,c’) From Economizer (b,c’) To Superheater (b,t’) c’ ≠ c c’ ≠ c t’ ≠ t Operating Conditions Pump (b,c) Economizer Boiler b B B Condenser Pressures (c): 1, (b,c) P b, Tsat(P b) 5, 15, 40 bar Condenser c PC , T (PC ) Superheater (b,t) c sat c B B P b, Tsat(P b) to Tt Boiler Pressures (b): 25, 50, 75, 100, 125 bar Precooler (b,c,t) Turbine (b,c,t) Turbine Inlet Temp. (t): 500, 600, 700, 800, 900°C From Precooler (b’,c,t’) To Turbine (b,c’,t) b’ ≠ b, t’ ≠ t c’ ≠ c [1] Duran, M. A. and I. E. Grossmann, Simultaneous optimization and heat integration of chemical processes, AIChE J., 32, 123, 1986. [2] Floudas, C. A., A. R. Ciric, and I. E. Grossmann, Automatic synthesis of optimum heat exchanger network configurations, AIChE J., 32, 2, 276, 1986. [3] Holiastos, H., V. Manousiouthakis, Minimum hot/cold/electric utility cost for heat exchange networks, Comp. & Chem. Eng., 26, 1, 3, 2002. Objective Function Summation representing overall cost of liquid fuels production F Feedstock costs (Cost ) El Electricity cost (Cost ) Seq CO2 sequestration cost (Cost ) CW Makeup freshwater cost (Cost ) U Levelized unit investment cost (Cost ) Overall model size: 16,739 continuous variables, 33 binary variables, 16,492 constraints, and 345 nonconvex terms (nonconvex MINLP) Case Studies Three case studies illustrate optimal topologies for 10,000 barrel/day BTL refinery GDK: Gasoline, diesel, kerosene in US ratios MD: Maximum production (≥75%) of diesel MK: Maximum production (≥75%) of kerosene Four case studies illustrate effect of capacity for GDK refinery Extra-small capacity (1,000 barrels/day) Small capacity (5,000 barrels/day) Medium capacity (10,000 barrels/day) Large capacity (50,000 barrels/day) 50% lifecycle GHG emissions compared to petroleum-based processes Biomass type: Forest residues (45 wt% moist.) Process Results: Topological Analysis Operating temperatures for biomass gasification (BGS), auto- thermal reforming (ATR), and water gas shift (WGS) are selected by the optimization model Production of liquid fuels via Fischer-Tropsch or methanol conversion Cobalt LTFT unit is Operating temperature Capacity o used for US ratio and ( C) selected by MINLP 10,000 BPD model maximum kerosene Operating FT Unit Methanol Case Temperatures FT Gas CO2 Study Low Nom. Upgrading Turbine Seq. BGS ATR WGS MTG MTOD Wax Wax Co US Ratios 900 1000 - - ZSM-5 Y - - - LTFT Max Diesel 900 1000 - - - - - Y - - Max Co 900 1000 - - Fract. - - - - Kerosene LTFT Methanol synthesis is used for A gas turbine and CO2 US ratios and maximum diesel sequestration are not utilized Process Results: Topological Analysis Topological differences are highlighted for different capacities Natural gas conversion pathway is always through auto-thermal reforming Consistent gasifier Cobalt LTFT unit is Output Fuels temperature as used as refinery United States capacity increases capacity increases demand ratios Operating FT Unit FT Methanol Gas CO Capacity Temperatures 2 Upgrading Turbine Seq.