Life-Cycle Energy and Greenhouse Gas Results of Fischer-Tropsch Diesel Produced from Natural Gas, Coal, and Biomass

Transcription

1 Life-Cycle Energy and Greenhouse Gas Results of Fischer-Tropsch Diesel Produced from Natural Gas, Coal, and Biomass Michael Wang, May Wu, and Hong Huo Center for Transportation Research Argonne National Laboratory 2007 SAE Government/Industry Meeting Washington, DC, May 14-16, 2007

2 Acknowledgement This study was funded by the Fuels Utilization Team of the FreedomCAR and Vehicle Technology Program of DOE s Energy Efficiency and Renewable Energy Office 2

3 Fischer-Tropsch Diesel (FT Diesel) Is A Premium Diesel Fuel Conventional Diesel FT Diesel Saturates 67.2% 91.8% Olefins 2.6% 5% Aromatics 30.2% 3.2% Carbon 86.59% 85.79% Hydrogen 12.67% 12.54% Sulfur 311 ppm 0.3 ppm Heat of Combustion Gross 19,633 Btu/lb 20,312 Btu/lb Net 18,477 Btu/lb 19,168 Btu/lb Specific Gravity Pour Point -5 F -5 F Cloud Point 4 F 4 F Viscosity 2.95 cst 1.55 cst Cetane Note: data is from Argonne testing; FT diesel specifications are for biomass-based SunDiesel TM by Choren Industries.

4 FT Diesel Offers Tailpipe Emission Reduction Benefits Relative to Petroleum Diesel: Argonne Test Results with the FTP-75 Cycle SunDiesel vs Conventional Diesel, % Difference 0 Bag 1 Bag 2 Bag 3 FTP HC NOx CO CO2 PM MPG

5 FT Diesel Can Be Produced from A Variety of Feedstocks Fischer-Tropsch process is a synthesis process to convert synthetic gas (syngas) to diesel fuels Brief history Developed by Germany during World War II to produce liquid fuels from coal Coal-based FT diesel production was modernized by South Africa s Sasol Many companies involve in FT diesel technology development and commercialization Syngas (thus FT diesel) can be produced from a variety of feedstocks Natural gas Coal via gasification Biomass via gasification Heavy refinery products such as pet coke via gasification 5

6 Argonne Has Applied Its GREET Model to Conduct Life-Cycle Analysis of Natural Gas, Coal, and Biomass to Liquid FT Diesel (GTL, CTL, and BTL) Fuel Cycle (Well-to-Wheels) (GREET 1 Series) Well to Pump Vehicle Cycle (GREET 2 Series) Pump to Wheels Key GREET features Emissions of greenhouse gases CO 2, CH 4, and N 2 O Emissions of six criteria pollutants Total and urban separately VOC, CO, NO x, SO x, PM 10 and PM 2.5 Energy use All energy sources Fossil fuels (petroleum, NG and coal) Petroleum Coal NG GREET and its documents are available at At present, there are over 3,500 registered GREET users from Auto industry, energy industry, governments, universities, etc. North America, Europe, and Asia The most recent GREET1.7 and GREET2.7 models were released in Feb

7 GREET Includes More Than 100 Fuel Production Pathways from Various Energy Feedstocks Petroleum: Conventional Oil Sands Natural Gas: NA Non-NA Nuclear Energy Coal Gasoline Diesel LPG Naphtha Residual oil CNG LNG LPG Methanol Dimethyl Ether FT Diesel and Naphtha Hydrogen Hydrogen Hydrogen FT Diesel Methanol Dimethyl Ether Corn Soybeans Sugar Cane Cellulosic Biomass: Switchgrass Fast growing trees Crop residues Forest residues Residual Oil Coal Natural Gas Nuclear Biomass Other Renewables Coke Oven Gas Ethanol Butanol Biodiesel Ethanol Hydrogen Methanol Dimethyl Ether FT Diesel Electricity Hydrogen 7

8 Several GTL Plants Are Either in Operation Or Under Construction These plants are located in regions where natural gas is stranded and inexpensive A commercial size GTL plant came on line in March 2007 in Qatar Is jointly owned by Sasol and Qatar Petroleum Has a capacity of 34k B/D (24k B/D FT diesel, 9k naphtha, and 1k B/D LPG) Consumes 330 million ft 3 of natural gas a day Could be expanded to 130k B/D in the future Several GTL plants are under construction in the Middle East and North Africa 8

9 CTL Plants Are in Operation or Under Consideration Sasol has the world largest CTL plants in South Africa Sasol One in Sasolburg in 1955 Sasol Two in Secunda in 1976 Sasol Three in Secunda in 1982 The Secunda facility has a capacity of 160k B/D Sasol CTL provides 28% of South Afirica s liquid fuels Sasol is in the second stage of feasibility studies for two 80k B/D facilities in China CTL plants are being proposed in the U.S. 9

10 Choren Industries in Germany Is Building a BTL Plant The Choren BTL plant is 43 MW in Freiberg, German Wood chips are first gasified and subsequently put through the Fischer-Tropsch process to produce FT diesel A LCA was completed for the Choren process with three scenarios Self-Sufficiency Basis Scenario (current plant design): H2, O2, and N2 are provided internally Future Scenario: H2 and O2 are provided externally Partial Self-Sufficiency Scenario: H2 is provided internally but O2 and N2 are provided externally 10

11 Life-Cycle Analysis of GTL Considers These Steps 11

12 Life-Cycle Analysis of CTL and BTL Considers These Steps Agricultural chemical production Agricultural chemical transportation Tree farming or forest residue collection Biomass gasification Syngas synthesis FT diesel transportation and storage 12 FT diesel at refueling station

13 A Schematic of GTL Production Process Recycle Gas CARBON DIOXIDE CO2 Removal Syngas Vapor FT LIQUID FUELS Air Separation Syngas Conversion (FT) Hydrocarbon Recovery AIR Oxygen POWER STEAM Heat Recovery & Syngas Treatment Hydrogen Liquid Hydrocarbons Power Generation NATURAL GAS Sulfur Guard Bed Autothermal Reforming Hydrogen Recovery Product Upgrading 13

14 A Schematic of CTL Production Process Air Separation Sulfur Recovery SULFUR Recycle Gas AIR Oxygen Syngas Treatment CARBON DIOXIDE COAL Coal Preparation Sulfur Guard Bed Syngas Syngas Conversion (FT) Vapor CO2 Removal Dehydration/ Compression FT LIQUID FUELS OXYGEN SLAG Gas ification Liquid Hydrocarbons Hydrocarbon Recovery Product Upgrading Hydrogen STEAM Hydrogen Recovery Autothermal Reforming 14

15 A Schematic of BTL Production Process Hydrogen CO Shift STEAM Syngas Treatment & Compression Syngas Syngas Conversion (FT) WOOD Syngas Vapor Wood Preparation Indirect Gasification Sulfur Guard Bed Liquid Hydrocarbons Hydrocarbon Recovery FT LIQUID FUELS Product Upgrading CHAR Power Generation POWER 15

16 Key Issues and Assumptions for FT Diesel Plants FT diesel plant designs Standalone to produce diesel, naphtha, and other products Co-generation of steam and/or electricity for export Post-synthesis refining/upgrading Affect product slate and product quality Ultimately affect WTW energy efficiencies and GHG emissions GTL plant assumptions in this study Energy conversion efficiency of 63% Carbon conversion efficiency of 80% CTL plant assumptions in this study Based on studies by National Energy Technology Laboratory (2003) and by Southern State Energy Board (2006) Low efficiency scenario with 47.4% efficiency High efficiency scenario with 52% efficiency A carbon capture and storage (CCS) case with a carbon capture rate of 85% at FT plants BTL plant assumptions in this study Based on a summary report on Choren Industries technology An energy efficiency of 47% for wood chip feedstock 16

17 Total Energy and Fossil Energy Use Per Million Btu of Fuel Produced and Used Energy Use: Btu/mmBtu 2,500,000 2,000,000 1,500,000 Total Energy Fossil Energy 1,000, ,000 0 Gasoline Diesel GTL CTL, Low Eff., W/O CCS CTL, Low Eff., W/ CCS CTL, High Eff., W/O CCS CTL, High Eff., W/ CCS BTL, Trees BTL, F. Residues 17

18 Natural Gas, Coal, and Oil Use Per Million Btu of Fuel Produced and Used Energy Use: Btu/mmBtu 2,500,000 2,000,000 1,500,000 Natural Gas Coal Petroleum 1,000, ,000 0 Gasoline Diesel GTL CTL, Low Eff., W/O CCS CTL, Low Eff., W/ CCS CTL, High Eff., W/O CCS CTL, High Eff., W/ CCS BTL, Trees BTL, F. Residues 18

19 Greenhouse Gas Emissions Per Million Btu of Fuel Produced and Used GHG Emissions: grams of CO2e/mmBtu 250, , , ,000 50, ,000 Gasoline Diesel GTL CTL, Low Eff., W/O CCS CTL, Low Eff., W/ CCS CTL, High Eff., W/O CCS CTL, High Eff., W/ CCS BTL, Trees BTL, F. Residues 19 GHG emissions here include CO2, CH4, and N2O

20 Total Energy and Fossil Energy Use Per Mile Energy Use: Btu/mile 10,000 8,000 6,000 Total Energy Fossil Energy 4,000 2,000 0 Gasoline Diesel GTL CTL, Low Eff., W/O CCS CTL, Low Eff., W/ CCS CTL, High Eff., W/O CCS CTL, High Eff., W/ CCS BTL, Trees BTL, F. Residues 20 Gasoline SI vehicle: on-road MPG of 24.8 Diesel CI vehicle: 22% improvement in gasoline equivalent MPG

21 Natural Gas, Coal, and Oil Use Per Mile Energy Use: Btu/mile 10,000 8,000 6,000 Natural Gas Coal Petroleum 4,000 2,000 0 Gasoline Diesel GTL CTL, Low Eff., W/O CCS CTL, Low Eff., W/ CCS CTL, High Eff., W/O CCS CTL, High Eff., W/ CCS BTL, Trees BTL, F. Residues 21 Gasoline SI vehicle: on-road MPG of 24.8 Diesel CI vehicle: 22% improvement in gasoline equivalent MPG

22 Grams of Greenhouse Gas Emissions Per Mile GHG Emissions: grams CO2e/mile 1, Gasoline Diesel GTL CTL, Low Eff., W/O CCS CTL, Low Eff., W/ CCS CTL, High Eff., W/O CCS CTL, High Eff., W/ CCS BTL, Trees BTL, F. Residues GHG emissions here include CO2, CH4, and N2O 22 Gasoline SI vehicle: on-road MPG of 24.8 Diesel CI vehicle: 22% improvement in gasoline equivalent MPG

23 Trade-Offs Between Petroleum Reductions and GHG Reductions Per-Mile Ratio Relative to Gasoline Vehicle GHG Ratio CTL, Low Effi. CTL, High Effi. GTL CTL, High Effi., CCS BTL, Forest Residues CTL, Low Effi., CCS BTL, Trees Petroleum Ratio Diesel Gasoline 23

24 Resource Supply and Feedstock Costs May Be Other Key Factors for Feedstock Choices Natural gas North American gas reserve of 265 trillion cubic feet World gas reserve of 6,112 trillion cubic feet U.S. wellhead NG price: $5-6/mmBtu Remote NG price of <$1/mmBtu? Coal U.S. reserve of 270 billon tons U.S. resource of 4 trillion tons U.S. minemouth coal price: $1.15/mmBtu Biomass Potential supply of 1.3 billion tons a year in the U.S. Price of $ /mmBtu (at $30-50/ton) 24

25 Conclusions GHG emission effects of FT diesel vary considerably among the three feedstocks Oil reduction benefits are similar among the three feedstocks Carbon capture and storage is assumed for CTL, should CCS be applied to GTL and BTL as well? Only limited FT diesel production options were examined in this analysis 25