Techno-Economic Feasibility Study of a Methanol Plant Using Carbon Dioxide and Hydrogen
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Techno-economic feasibility study of a methanol plant using carbon dioxide and hydrogen Judit Nyári Master of Science Thesis KTH School of Industrial Engineering and Management Energy Technology TRITA-ITM EX 2018:712 Division of Energy Systems Analysis SE-100 44 STOCKHOLM Master of Science Thesis TRITA-ITM EX 2018:712 Techno-economic feasibility study of a methanol plant using carbon dioxide and hydrogen Judit Nyári Approved Examiner Supervisor 26.10.2018 Professor Mark Howells Shahid Hussain Siyal Commissioner Contact person Abstract In 2015, more than 80% of energy consumption was based on fossil resources. Growing population especially in developing countries fuel the trend in global energy consumption. This constant increase however leads to climate change caused by anthropogenic greenhouse gas (GHG) emissions. GHG, especially CO2 mitigation is one of the top priority challenges in the EU. Amongst the solutions to mitigate future emissions, carbon capture and utilization (CCU) is gaining interest. CO2 is a valuable, abundant and renewable carbon source that can be converted into fuels and chemicals. Methanol (MeOH) is one of the chemicals that can be produced from CO2. It is considered a basic compound in chemical industry as it can be utilised in a versatility of processes. These arguments make methanol and its production from CO2 a current, intriguing topic in climate change mitigation. In this master’s thesis first the applications, production, global demand and market price of methanol were investigated. In the second part of the thesis, a methanol plant producing chemical grade methanol was simulated in Aspen Plus. The studied plants have three different annual capacities: 10 kt/a, 50 kt/a and 250 kt/a. They were compared with the option of buying the CO2 or capturing it directly from flue gases through a carbon capture (CC) unit attached to the methanol plant. The kinetic model considering both CO and CO2 as sources of carbon for methanol formation was described thoroughly, and the main considerations and parameters were introduced for the simulation. The simulation successfully achieved chemical grade methanol production, with a high overall CO2 conversion rate and close to stoichiometric raw material utilization. Heat exchanger network was optimized in Aspen Energy Analyzer which achieved a total of 75% heat duty saving. The estimated levelised cost of methanol (LCOMeOH) ranges between 1130 and 630 €/t which is significantly higher than the current listed market price for fossil methanol at 419 €/t. This high LCOMeOH is mostly due to the high production cost of hydrogen, which corresponds to 72% of LCOMeOH. It was revealed that selling the oxygen by-product from water electrolysis had the most significant effect, reducing the LCOMeOH to 475 €/t. Cost of electricity also has a significant influence on the LCOMeOH, and for a 10 €/MWh change the LCOMeOH changed by 110 €/t. Finally, the estimated LCOMeOH was least sensitive for the change in cost of CO2. When comparing owning a CC plant with purchasing CO2, it was revealed that purchasing option is only beneficial for smaller plants. Keywords methanol, CCU, CO2 hydrogenation, simulation, Aspen, economics, levelised cost Foreword This master’s thesis was carried out under Industry Decarbonisation R&D Portfolio of Vattenfall AB between February and September 2018. I thank Anders Wik for the opportunity to conduct my master’s thesis at a leading European energy company. I especially thank Johan Westin for his valuable advice and guidance during the period of the project, and Mohamed Magdeldin for the help and recommendations about the simulations in Aspen. I am also grateful for the feedback and comments from Professor Mika Järvinen, Anders Wik and Nader Padban. I would also like to thank my family, especially my husband, for the love and support during this journey. Helsinki, 8th October 2018 Judit Nyári Contents 1 Introduction .................................................................................................................... 1 1.1 Methodology and objective ..................................................................................... 2 2 Methanol ........................................................................................................................ 3 2.1 Applications of methanol ........................................................................................ 3 2.1.1 Methanol in the chemical industry ................................................................... 5 2.1.2 Methanol in the petrochemical industry .......................................................... 5 2.1.3 Other applications .......................................................................................... 10 2.2 Global methanol market and its cost of production .............................................. 11 2.3 Production of methanol ......................................................................................... 13 2.3.1 Conventional synthesis of methanol .............................................................. 14 2.3.2 Methanol production via CO2 hydrogenation ................................................ 21 3 Techno-economic study of a CO2 hydrogenation methanol plant ............................... 28 3.1 Literature review ................................................................................................... 28 3.2 Methodology ......................................................................................................... 29 3.2.1 Water electrolysis unit ................................................................................... 30 3.2.2 Carbon dioxide capture unit ........................................................................... 31 3.2.3 Methanol synthesis and distillation plant ....................................................... 32 3.2.4 Assumptions and calculations for economic analysis .................................... 38 4 Results .......................................................................................................................... 42 4.1 Technical performance .......................................................................................... 42 4.1.1 Results of heat optimization .......................................................................... 42 4.2 Economic results ................................................................................................... 44 4.2.1 Sensitivity analysis ........................................................................................ 47 5 Conclusion ................................................................................................................... 50 6 References .................................................................................................................... 52 Appendix 1 Detailed stream tables for methanol plants Appendix 2 Heat streams for methanol plants with 10 kt/a and 250 kt/a output Appendix 3 Composite Curves and Grand Composite Curve Appendix 4 Heat exchanger network designs Appendix 5 List of heat exchangers from HEN designs after heat integration Appendix 6 Annual fixed and variable OPEX List of figures Figure 2.1: Value chain of methanol ..................................................................................... 4 Figure 2.2: Schematic flow diagram of the fixed-bed methanol-to-gasoline process ........... 7 Figure 2.3: Chemicals and end-products produced by MTO process .................................... 8 Figure 2.4: a) Global methanol demand by application in 2017 (on the right), b) methanol demand by region in million tons (on the left) .................................................................... 11 Figure 2.5: Methanex quarterly average European posted contract methanol price ........... 12 Figure 2.6: Production costs and production capacity of (bio)methanol for various feedstock .............................................................................................................................. 13 Figure 2.7: Conventional methanol production ................................................................... 14 Figure 2.8: a) Adiabatic reactor with direct cooling, i.e. quench reactor; b) adiabatic reactor with indirect heat exchange; c) reactor with external cooling ............................................. 16 Figure 2.9: Radial water-cooled tubular reactor, Johnson Matthey’s DAVY™ ................. 17 Figure 2.10: Lurgi’s two-stage process design .................................................................... 18 Figure 2.11: LPMeOH slurry reactor ................................................................................... 19 Figure 2.12: Two-column distillation system from Lurgi ................................................... 20 Figure 2.13: Simplified methanol synthesis process ........................................................... 21 Figure 2.14: Effect of temperature on CO2 conversion and methanol selectivity over −1 Cu/Zn/Al (50:30:20) catalyst (CO2:H2 ratio 1:3, GHSV 2000 h and pressure 20 bar) ...... 23 Figure 2.15: Comparison of the by-products in crude MeOH for various feed gas compositions and process conditions ................................................................................... 24 Figure 2.16: Estimated methanol production costs for different concepts of methanol synthesis in 2005 .................................................................................................................. 25 Figure 3.1: Block diagram of the boundary conditions