Process Analysis and Design: Objectives and Introduction

Transcription

1 Process Analysis and Design: Objectives and Introduction Presented by Dr. Richard L. Bain, Principal Research Supervisor Biorefinery Analysis, National Bioenergy Center Presented to the NSF Biomass Thermochemical Conversion Roadmap Workshop Washington, D.C. June 25-26, /17/07 1

2 Thrust Area Objective Slide To identify challenges and opportunities for process systems that implement the various chemical routes Including engineering design of single process units, process systems, and supply chains Addressing both technical and economic factors Including advantages, disadvantages, and tradeoffs in process engineering and design 7/17/07 2

3 Process Analysis and Design The application of scientific methods to the recognition and definition of problems and the development of procedures for their solution Involves an examination of the overall process, alternative processes, and economics Steps 1. Mathematical specification of the problem for the given physical situation 2. Detailed analysis to obtain mathematical models, and 3. Synthesis and presentation of results to ensure full comprehension Reference: Himmelblau, D. M. and K. B. Bischoff (1968). Process Analysis and Simulation, John Wiley & Sons, NY,NY. 7/17/07 3

4 Process Analysis and Design Other Definitions Process: an actual series of operations or treatment of materials Model: a mathematical representation of the real process System: The assemblage of elements which are tied together by common flows of materials and/or information Parameter: a property of the process or its environment, that can be assigned arbitrary numerical values; also, a constant or coefficient in an equation Simulation: the study of a system or its parts by manipulation of its mathematical representation or its physical model Reference: Himmelblau, D. M. and K. B. Bischoff (1968). Process Analysis and Simulation, John Wiley & Sons, NY,NY. 7/17/07 4

5 Examples of Disciplines and Applications Disciplines Thermodynamics Transport Phenomena Phase Equilibria Mass Transfer Heat Transfer Chemical Reaction Kinetics Mathematics Statistics, Multivariate Analysis Economics Applications Reactor Design Separations Material Transfer and Handling Life Cycle and Net Energy Analysis 7/17/07 5

6 Examples of Process Modeling Tools Kinetics Chemkin CFD Fluent Thermo/Phase Equilibria - FACT ASPEN ASPEN - Icarus Process Estimator (IPE) EXCEL Crystal Ball At-Risk R&D Process Modeling & Design Material & Energy Balance Capital & Project Cost Estimates Economic Analysis Unscrambler MatLab Environmental Analysis General: EXCEL, STELLA (dynamic modeling) LCA - TEAM - SimaPro - GREET 7/17/07 6

7 Process Modeling Example 7/17/07 7

8 Biomass to Biofuels via a syngas intermediate* has a number of processing configurations Primary Conversion Tar mitigation Syngas conditioning Biofuel production biomass Dry-Ash Gasifier (Indirect or Direct) Flash Pyrolysis Slow Pyrolysis Torrefaction Quench/Scrub Catalytic Tar Reformer Thermal Cracking Slagging Entrained Flow Gasifier Particulate removal Sulfur removal CO 2, CH 4, Light HC removal H 2 /CO shift Trace removal Fischer- Tropsch Methanol DME Mixed Alcohol Hydrogen *Adapted from van der Drift and Boerrigter Synthesis Gas from Biomass for fuels and 7/17/07 chemicals ECN-C , January

9 NREL 150 kw t Thermochemical Process Development Unit 7/17/07 9

10 Feedstock Fuel Variability Feedstock Composition NREL TCPDU Syngas Composition (S/B = 1) Wood Proximate Analysis (wt %) Corn Stover BioChem Residue Vol% Wood Corn Stover BioChem Residue Moisture (63.76) H ? Ash CO ? Volatiles CO ? Fixed C CH ? Ultimate Analysis (wt%) C 2 H ? C H N O S Benzene (mg/nm 3 ) 6,500 10,000 Gas cleanup requirements will be dictated by biorefinery residue compositions that are a function of feedstock and pretreatment/process conditions? 7/17/07 10

11 7/17/07 11

12 This simplified mixed alcohols flowsheet shows the type of processing steps Flue Gas Biomass Feed Handling and Conditioning Dried Biomass Gasification Crude Syngas Tar Reforming and Gas Cleaning Clean Syngas Syngas Compression High P Syngas Syngas Recycle Configuration Dependent on Specific Design Methanol Mixed Alcohol Synthesis Crude Products Preliminary Separation H2, CO, CO2, CH4 Mixed Alcohols C3 + Alcohols Ethanol 7/17/07 12

13 NREL Mixed Alcohols Design Case 7/17/07 13

14 Gaps and Needs Composition data oxygenated oils Physical & Thermodynamics Properties especially oxygenates etc This slide in progress 7/17/07 14

15 Illustration 7/17/07 by Oak Ridge National Lab 15