Project: BiG>East (EIE/07/214) Biogas purification and assessment of the natural gas grid in Southern and Eastern Europe Deliverable 2.5 Task 2.5 Mag. Heinz Praßl Ing. Gerhard Agrinz GmbH Emmerich-Assmann-Gasse 6 8430 Leibnitz, Austria Leibnitz, 23.06.2008 Elaborated with input of the BiG>East partners Krasin Georgiev, Denitsa Dimitrova, Biljana Kulisic, Konstantinos Sioulas, Ilze Dzene, Augustin Ofiteru, Mihai Adamescu, Florian Bodescu, Aleks Jan, and Dominik Rutz. With the support of: The sole responsibility for the content of this publication lies with the authors. It does not represent the opinion of the Community. The European Commission is not responsible for any use that may be made of the information contained therein Task 2.5 Report Index Foreword................................................................................................................................... 5 1. Introduction .......................................................................................................................... 6 2. Properties of the natural gas grid ....................................................................................... 6 2.1 Classification according to grid levels .......................................................................................... 6 2.2 Classification according to pressure levels.................................................................................. 7 2.2.1 Low pressure grid ..................................................................................................................................... 7 2.2.2 Medium and high pressure grids ............................................................................................................. 7 2.3 Technical criteria for the feed-in of biogas ................................................................................... 8 2.3.1 Classification of the gas supply companies ........................................................................................... 9 2.3.2 Feed-in of admixture gas .......................................................................................................................... 9 2.4 Area restrictions of biogas feed-in................................................................................................. 9 3. Requirements of biogas composition............................................................................... 10 3.1 Biogas properties........................................................................................................................... 10 3.2 Gas property requirements for feed-in into the grid .................................................................. 11 3.2.1 Definition of gas labels ........................................................................................................................... 12 3.2.2 Discussion of technical combustion data ............................................................................................ 14 3.2.3 Discussion of gas impurities ................................................................................................................. 15 3.2.4 Conditioned gases from renewable sources for the public gas supply ............................................. 17 3.2.5 Gas odorisation ....................................................................................................................................... 18 3.2.6 Gas billing ................................................................................................................................................ 18 3.3 Comparison of international quality requirements..................................................................... 18 3.3.1. Quality requirements in Germany ......................................................................................................... 18 3.3.2. Quality requirements in Austria ............................................................................................................ 19 3.3.3. Quality requirements in Sweden ........................................................................................................... 20 3.3.4. Quality requirements in Denmark ......................................................................................................... 20 3.3.5. Quality requirements in Switzerland .................................................................................................... 21 3.4 Comparison of raw biogas with the quality requirements for feed-in into the grid ................ 22 4. Biogas cleaning and conditioning .................................................................................... 27 4.1 Biogas desulphurisation process ................................................................................................ 27 4.1.1 Biological desulphurisation ................................................................................................................... 28 4.1.2 Chemical / physical desulphurisation ................................................................................................... 30 4.2 Biogas drying ................................................................................................................................. 33 4.2.1 Condensation .......................................................................................................................................... 34 4.2.2 Membrane technology ............................................................................................................................ 34 4.2.3 Freezing technology ............................................................................................................................... 35 4.2.4 Dehumidification with triethyleneglycol ............................................................................................... 35 4.2.5 Dehumidification with potassium chloride ........................................................................................... 36 Ing. Gerhard Agrinz GmbH 2 Task 2.5 Report 4.3 Removal of siloxanes .................................................................................................................... 37 4.4 Other gas contaminants ................................................................................................................ 38 4.5 Biogas conditioning – Methane enrichment process for biogas .............................................. 38 4.5.1 Pressure swing adsorption with a carbon molecular sieve ................................................................ 38 4.5.2 Gas wash ................................................................................................................................................. 39 4.5.3 Low pressure – membrane absorption ................................................................................................. 41 4.5.4 Gas permeation using membranes ....................................................................................................... 42 4.5.5 Cryogenic gas separation ...................................................................................................................... 43 4.5.6 Comparison of processes for methane enrichment ............................................................................ 43 5. Technical requirements for the feed-in of biogas into the natural gas grid................... 46 5.1 Connection lines ............................................................................................................................ 46 5.2 Gas compression ........................................................................................................................... 47 5.2.1 Compressor stations and pressurisation systems .............................................................................. 47 5.2.2 Biogas compression ............................................................................................................................... 47 5.3 Gas storage..................................................................................................................................... 49 5.4 Gas pressure measurement and regulation equipment ............................................................ 51 5.5 Gas properties measurement equipment .................................................................................... 51 5.6 Odorisation equipment.................................................................................................................. 52 5.7 Conditioning and gas mixing equipment .................................................................................... 52 6. Examples of Biogas Feed-in.............................................................................................. 53 6.1 Germany.......................................................................................................................................... 53 6.2 Austria ............................................................................................................................................. 54 6.3 Sweden............................................................................................................................................ 55 6.4 Switzerland ..................................................................................................................................... 57 7. Summary............................................................................................................................