Thermodynamic_Analysis_of_the_coal_to_SNG_process - Thermodynamic Analysis of Coal to Synthetic Natural Gas Process Lei Chen1 Rane Nolan1 Shakeel

Thermodynamic_Analysis_of_the_coal_to_SNG_process -...

This preview shows page 1 - 4 out of 31 pages.

Thermodynamic Analysis of Coal to Synthetic Natural Gas Process Lei Chen1, Rane Nolan1, Shakeel Avadhany2 Supervisor: Professor Ahmed F. Ghoniem11. Mechanical Engineering, MIT 2. Materials Science and Engineering, MIT 77 Massachusetts Avenue, Room 3-335 Cambridge, MA 02139-4307Tel: (617)-258-8740[email protected], [email protected], [email protected] Submitted: May 11th, 2009 AbstractNatural gas is a clean energy source of the fossil fuels that dominates today’s energy supply. The Coal-to-Synthetic Natural Gas (SNG) concept has been successfully demonstrated as a feasible energy production concept. As a final report for term project of Fundamentals of Advanced Energy Conversion, the scope of this research includes a state-of-the-art technologies review for Coal-to-SNG, the thermodynamic parametric study of main components in this process, and the efficiency assessment of the overall energy system implementing different gasification technologies, as well as the novel hydromethanation process. Results show that the optimized oxygen-steam-carbon constraints for Coal-to-SNG are in the range of ~0.25-0.3 for O2/C, and ~1.5-2 for H2O/C. High pressure is favorable to increase the methanation reaction, and increase the methane yield for hydromethanation. Efficiency analysis shows the moving-bed dry ash gasification achieves higher energy conversion efficiency (67%) than entrained flow gasification (57%) for the overall Coal-to-SNG process. Hydromethanation is a promising novel route with about 70% energy efficiency; however it is still under development because of the technique challenges on catalysts.
iTable of ContentsTable of Contents.....................................................................................................................................i List of Tables and Figures.......................................................................................................................ii 1 INTRODUCTION..............................................................................................................................1 1.1 Energy Landscape.....................................................................................................................1 1.2 Motivation of Analysis..............................................................................................................1 2 OVERVIEW OF THE COAL-TO-SNG PLANTS IN OPERATION............................................2 2.1 GREAT PLAINS SYNFUELS PLANT....................................................................................2 2.2 GREAT POINTS PILOT PLANT.............................................................................................2 3 FUNDAMENTALS OF COAL-TO-SNG PROCESSES.................................................................5 3.1 Gasification...............................................................................................................................5 3.2 Water Gas Shift (WGS).............................................................................................................5 3.3 Methanation..............................................................................................................................6 3.4 Hydromethanation (Catalytic steam gasification).....................................................................8 4 APPROACHES AND BASIC ASSUMPITIONS OF THE STUDY.............................................10 4.1 Thermodynamic analysis[12]..................................................................................................10 4.2 Assumptions............................................................................................................................10 4.2.1 Process simplification..................................................................................................10 4.2.2 Coal analysis................................................................................................................10 5 RESULTS AND DISCUSSION.......................................................................................................12 5.1 Parametric studies...................................................................................................................12 5.1.1 Gasification process.....................................................................................................12 5.1.2 Water Gas Shift process...............................................................................................17 5.1.3 Methanation process.....................................................................................................18 5.1.4 Hydromethanation (Catalytic steam gasification) process...........................................18 5.2 Efficiency analysis..................................................................................................................21 5.2.1 Base case study: GPSP process with Lurgi gasifier.....................................................24 5.2.2 Efficiency analysis implementing alternative gasifier..................................................24 5.2.3 Efficiency analysis implementing hydromethanation technology................................25 6. CONCLUSIONS.............................................................................................................................27 REFERENCES:....................................................................................................................................28
iiList of Tables and FiguresTable 1. Typical operating conditions and gas compositions in the 3-stage methanation process..........7 Table 2: Unit operation models and operating conditions.....................................................................10 Table 3: Proximate and ultimate analysis of coal samples....................................................................11 Table 4: Operating condition of typical Lurgi dry ash and GE-Texaco gasifier[2, 11].........................16 Table 5: Syngas composition at process exit (with Lurgi Dry Ash gasification)..................................22 Table 6: Syngas composition at process exit (with GE-Texaco gasification).......................................

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture