Bio-SNG from Thermal Gasification - Process Synthesis, Integration and Performance

Biomethane or synthetic natural gas (Bio-SNG) produced from gasified renewable woody biomass is a promising option for replacing fossil natural gas. The complete interchangeability with natural gas in all its conventional applications such as in the power generation, transportation and chemical industry sector is of particular interest. This work presents results from a comprehensive process integration study of different process alternatives for Bio-SNG production from gasified biomass. The influence of the main conversion steps in the process chain – drying, gasification, gas cleaning, methanation, and gas upgrade – on the overall process performance is investigated. Process bottlenecks and both heat and material integration opportunities are highlighted. Using future energy market scenarios the energetic, economic, and carbon footprint performance of the investigated processes are evaluated from a system perspective clearly showing the sensitivity of the obtained results to underlying assumptions. It is shown that drying of the biomass feedstock prior to gasification using excess process heat – using steam drying or low-temperature air drying technology – is an important aspect for improving the process energy efficiency. The results also indicate that indirect and direct gasification technologies perform equally well within the overall Bio-SNG production process. Existing infrastructure in the form of biomass-fired combined heat and power plants based on fluidised bed combustion technology presents interesting opportunities for integrating indirect gasification for Bio-SNG production, with beneficial effects on the cogeneration of electricity from the Bio-SNG process excess heat. The choice of methanation technology between fixed and fluidised bed is not a critical one with respect to process integration, since both technologies allow for efficient heat recovery and consequent cogeneration. For gas upgrade, in particular removal of CO2 from the product gas, amine based separation is shown to achieve better energy efficiency and economic performance than membrane based or pressure swing adsorption processes. Preliminary estimations of Bio-SNG costs are significantly higher than current natural gas prices, thus dedicated and long term policy measures are necessary in order to stimulate Bio-SNG production. The process integration aspects presented in this thesis can contribute to reducing production costs by increasing energy efficiency and in consequence increasing economic robustness of Bio-SNG process concepts.

[1]  Per-Anders Hansson,et al.  Greenhouse gas balance of harvesting stumps and logging residues for energy in Sweden , 2011 .

[2]  Kj Krzysztof Ptasinski,et al.  Exergy analysis of synthetic natural gas production method from biomass , 2010 .

[3]  T. Schildhauer,et al.  The regenerative effect of catalyst fluidization under methanation conditions , 2006 .

[4]  Aie.  World Energy Outlook 2011 , 2011 .

[5]  Jens R. Rostrup-Nielsen,et al.  High temperature methanation sintering and structure sensitivity , 2007 .

[6]  Martin Gassner.  Process Design Methodology for Thermochemical Production of Fuels from Biomass , 2010 .

[7]  W. A. Amos,et al.  Report on Biomass Drying Technology , 1999 .

[8]  Truls Liliedahl,et al.  Biomass Gasification - A Synthesis of Technical Barriers and Current Research Issues for the Deployment at Large Scale , 2013 .

[9]  Hartmut Spliethoff,et al.  Small‐scale production of synthetic natural gas by allothermal biomass gasification , 2013 .

[10]  Anthony V. Bridgwater,et al.  Progress in Thermochemical Biomass Conversion , 2001 .

[11]  Theodoros Damartzis,et al.  Thermochemical conversion of biomass to second generation biofuels through integrated process design—A review , 2011 .

[12]  Markku Hurme,et al.  Technoeconomical study of bio-SNG production from lignocellulosic biomass , 2011 .

[13]  M. Beil,et al.  Biogas upgrading to biomethane , 2013 .

[14]  Erik Hektor.  Post-Combustion CO2 Capture in Kraft Pulp Mills - Technical, Economic and System Aspects , 2008 .

[15]  Jan Szargut,et al.  Exergy Analysis of Thermal, Chemical, and Metallurgical Processes , 1988 .

[16]  T. J. Kotas,et al.  The Exergy Method of Thermal Plant Analysis , 2012 .

[17]  Mats Söderström,et al.  Biomass gasification in district heating systems - The effect of economic energy policies , 2010 .

[18]  K. Svoboda,et al.  Integration of biomass drying with combustion/gasification technologies and minimization of emissions of organic compounds , 2009 .

[19]  Jukka-Pekka Spets.  A NEW MULTISTAGE DRYING SYSTEM , 2001 .

[20]  Francesco Cherubini,et al.  Crop residues as raw materials for biorefinery systems - A LCA case study , 2010 .

[21]  F. W. Moeller,et al.  METHANATION OF COAL GAS FOR SNG , 1974 .

[22]  Hermann Hofbauer,et al.  H2 rich product gas by steam gasification of biomass with in situ CO2 absorption in a dual fluidized bed system of 8 MW fuel input , 2009 .

[23]  Heejoon Kim,et al.  The reduction and control technology of tar during biomass gasification/pyrolysis: An overview , 2008 .

[24]  A. Gómez-Barea,et al.  Modeling of biomass gasification in fluidized bed , 2010 .

[25]  Robin Smith,et al.  Chemical Process: Design and Integration , 2005 .

[26]  T. A. Milne,et al.  Biomass Gasifier "Tars": Their Nature, Formation, and Conversion , 1998 .

[27]  Ian C. Kemp,et al.  Pinch Analysis and Process Integration: A User Guide on Process Integration for the Efficient Use of Energy , 2007 .

[28]  T. Schildhauer,et al.  Production of synthetic natural gas (SNG) from coal and dry biomass - A technology review from 1950 to 2009 , 2010 .

[29]  M. Fatih Demirbas,et al.  Biorefineries for biofuel upgrading: A critical review , 2009 .

[30]  R.W.R. Zwart,et al.  Oil‐based gas washing—Flexible tar removal for high‐efficient production of clean heat and power as well as sustainable fuels and chemicals , 2009 .

[31]  Eva-Lotta Lindholm,et al.  Energy Use and Environmental Impact of Roundwood and Forest Fuel Production in Sweden , 2010 .

[32]  Henrik Thunman,et al.  Highly efficient electricity generation from biomass by integration and hybridization with combined cycle gas turbine (CCGT) plants for natural gas , 2010 .

[33]  Harold Boerrigter,et al.  Methanation of Milena product gas for the production of bio-SNG , 2005 .

[34]  M. Mozaffarian.  FEASIBILITY OF BIOMASS / WASTE-RELATED SNG PRODUCTION TECHNOLOGIES , 2003 .

[35]  Hermann Hofbauer,et al.  In-Bed Catalytic Tar Reduction in a Dual Fluidized Bed Biomass Steam Gasifier , 2004 .

[36]  Henrik Thunman,et al.  Composition of Volatile Gases and Thermochemical Properties of Wood for Modeling of Fixed or Fluidized Beds , 2001 .

[37]  M. Seemann.  Methanation of biosyngas in a fluidized bed reactor , 2007 .

[38]  A. Lyngfelt,et al.  Synthesis gas generation by chemical-looping reforming in a continuously operating laboratory reactor , 2006 .

[39]  Robert C. Brown,et al.  Ancillary equipment for biomass gasification , 2002 .

[40]  Laura Cozzi.  World Energy Outlook 2011 , 2012 .

[41]  J. Drexhage.  Proposal for a DIRECTIVE OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL on the reduction of the impact of certain plastic products on the environment , 2002 .

[42]  H. Veringa,et al.  The production of synthetic natural gas (SNG): A comparison of three wood gasification systems for energy balance and overall efficiency , 2010 .

[43]  Ethniko Metsovio Polytechneio.  European energy and transport : trends to 2030 , 2003 .

[44]  C. M. Kinoshita,et al.  A review of sorbent materials for fixed bed alkali getter systems in biomass gasifier combined cycle power generation applications , 1998 .

[45]  C. M. Meijden,et al.  Waste wood fueled gasification demonstration project , 2011 .

[46]  Simon Harvey,et al.  Integration Opportunities for Substitute Natural Gas (sng) Production in an Industrial Process Plant , 2012 .

[47]  D. G. Christian,et al.  Biomass for Renewable Energy, Fuels, and Chemicals , 2000 .

[48]  Henrik Thunman,et al.  A cost effective concept for generation of heat, electricity and transport fuel from biomass in fluidized bed boilers – using existing energy infrastructure , 2007 .

[50]  François Maréchal,et al.  Hydrothermal gasification of waste biomass: process design and life cycle asessment. , 2009, Environmental science & technology.

[51]  F. Maréchal,et al.  Thermo-economic process model for thermochemical production of Synthetic Natural Gas (SNG) from lignocellulosic biomass , 2009 .

[52]  Simon Harvey,et al.  Scenarios for assessing profitability and carbon balances of energy investments in industry , 2010 .

[53]  Regeringen och Regeringskansliet.  Fossiloberoende fordonsflotta - ett steg på vägen mot nettonollutsläpp av växthusgaser , 2012 .

[54]  Pekka Ahtila,et al.  Evaluation of energy efficiency in biofuel drying by means of energy and exergy analyses , 2005 .

[55]  Erik O. Ahlgren,et al.  Biokombi Rya - Biobränsleförgasning satt i system , 2007 .

[56]  François Maréchal,et al.  Thermo-economic optimisation of the polygeneration of synthetic natural gas (SNG), power and heat from lignocellulosic biomass by gasification and methanation , 2012 .

[57]  R. Ocampo-Pérez,et al.  Adsorption of Fluoride from Water Solution on Bone Char , 2007 .

[58]  J. R. Hess,et al.  Process Design and Economics for Conversion of Lignocellulosic Biomass to Ethanol , 2011 .

[59]  B. Vreugdenhil,et al.  Bioenergy II: Scale-Up of the Milena Biomass Gasification Process , 2009 .

[60]  M. Waldner,et al.  Renewable Production of Methane from Woody Biomass by Catalytic Hydrothermal Gasification , 2005 .

[61]  S. Channiwala,et al.  A UNIFIED CORRELATION FOR ESTIMATING HHV OF SOLID, LIQUID AND GASEOUS FUELS , 2002 .

[62]  R. Hayes,et al.  A study of the nickel-catalyzed methanation reaction , 1985 .

[63]  Henrik Thunman,et al.  First Experiences with the New Chalmers Gasifier , 2009 .

[64]  Kj Krzysztof Ptasinski,et al.  Exergy analysis of biomass-to-synthetic natural gas (SNG) process via indirect gasification of various biomass feedstock , 2011 .

[65]  Marcus R. Olsson.  Simulations of Evaporation Plants in Kraft Pulp Mills: Including Lignin Extraction and Use of Excess Heat , 2009 .

[66]  Martin Kaltschmitt,et al.  Bio-SNG production — concepts and their assessment , 2012 .

[67]  Nina Johansson,et al.  Production of liquid biogas, LBG, with cryogenic and conventional upgrading technology - Description of systems and evaluations of energy balances , 2008 .

[68]  Hermann Hofbauer,et al.  Stoichiometric Water Consumption of Steam Gasification by the FICFB‐Gasification Process , 2008 .

[69]  Detlef Stolten,et al.  Power to Gas , 2013 .

[70]  Bodo Linnhoff,et al.  A User guide on process integration for the efficient use of energy , 1994 .