11 Methane capturing 11 Methane capturing 1 127

11 – Methane capturing 11 Methane capturing 1 1/27

11 – Methane capturing “Landfill gas extraction system in the making”, Braambergen landfill 2/27

11 – Methane capturing Overview n 11. 1 Types of extraction systems n 11. 2 Operational aspects n 11. 3 Management and maintenance 3/27

11 – Methane capturing 11. 1 Types of extraction systems 11. 1 Types of extractions systems 4/27

11 – Methane capturing 11. 1 Types of extraction systems Landfill gas dynamics n Three main factors influence the migration of landfill gases: n Pressure n Permeability and n Diffusion 5/27

11 – Methane capturing 11. 1 Types of extraction systems Landfill gas extraction n n Landfill gas is: n explosive in air n a Greenhouse Gas (GHG) and n toxic to humans …. and therefore should be controlled on landfills 6/27

11 – Methane capturing 11. 1 Types of extraction systems Landfill gas extraction n There are two types of landfill gas extraction: 1. passive 2. active 7/27

11 – Methane capturing 11. 1 Types of extraction systems Passive landfill gas extraction 8/27

11 – Methane capturing 11. 1 Types of extraction systems Active landfill gas extraction n Active landfill gas extraction demands the following: 1. Extraction system 2. Compressor 3. Flare installation or 4. Landfill gas utilization 9/27

11 – Methane capturing 11. 1 Types of extraction systems Extraction system n There are several types of active landfill gas extraction systems: 1. Vertical 2. Horizontal 3. Slope 4. Point 10/27

11 – Methane capturing 11. 1 Types of extraction systems Vertical Cell wise Conventional HDPE piping (non perforated) Build up GRAVEL Build up + early extraction HDPE piping (perforated) 11/27

11 – Methane capturing 11. 1 Types of extraction systems Horizontal 12/27

11 – Methane capturing 11. 1 Types of extraction systems Slope 13/27

11 – Methane capturing 11. 1 Types of extraction systems Point 14/27

11 – Methane capturing 11. 1 Types of extraction systems Gas well connection RULE OF THUMB: 4 GAS WELLS PER HA 15/27

11 – Methane capturing 11. 1 Types of extraction systems Gas well connection 16/27

11 – Methane capturing 11. 1 Types of extraction systems Compressor 17/27

11 – Methane capturing 11. 2 Operational aspects 18/27

11 – Methane capturing 11. 2 Operational aspects Explosive conditions during start up • Due to safety procedures, explosive conditions must be avoided at all times. The start up procedure to avoid explosive conditions is as follows: 1. 2. 3. 4. 5. 6. Every valve in the extraction system must be opened; At the flare installation or the booster station venting piping needs to be constructed at safe place within landfill boundaries (NOT nearby housing, scavengers or registration offices) and Under current conditions, landfill gas will force out the air naturally. Flare and extraction system full with landfill gas Start up flare at lowest extraction rate Monitor landfill gas quality and explosion limits frequently 19/27

11 – Methane capturing 11. 2 Operational aspects Explosive conditions § Landfill gas contains methane § Explosive conditions of methane in air achieved between 5 - 15% § Over extraction of the extraction system could result into high infiltration of ambient air and explosive conditions could be reached § Monitoring again is essential! 20/27

11 – Methane capturing 11. 2 Operational aspects Landfill gas monitoring n Monitoring equipment Anemo meter Digital manometer Gas analyser 21/27

11 – Methane capturing 11. 2 Operational aspects Landfill gas monitoring n Gas analyser can measure: 1. CH 4 2. CO 2 3. O 2 4. N 2 (= 100% - CH 4% - CO 2% - O 2%) 22/27

11 – Methane capturing 11. 2 Operational aspects Landfill gas monitoring n If CH 4 and O 2 concentration respectively in a gas well is: n > 50% and < 1% then more extraction n < 50% and > 1% then less extraction 23/27

11 – Methane capturing 11. 2 Operational aspects Landfill gas monitoring n If N 2: O 2 ratio is: n >5 indicator suction of ambient air n <4 indicator leakage piping extraction system 24/27

11 – Methane capturing 11. 3 Management and maintenance 11. 3 Management and Maintenance 25/27

11 – Methane capturing n n 11. 3 Management and maintenance Check at the flare installation: n Flowmeter and indicator function (CDM requirements) n State O 2 analyser n Automatic shut down in case of explosive mixtures . . on a regular basis 26/27

11 – Methane capturing n 11. 3 Management and maintenance Maintenance should be performed by: n Maintenance scheme n Arrange spare part list critical items (compressor, flare, extraction system) n The later enables planning and minimises down-time of extraction system and, therefore, minimises greenhouse gas emissions 27/27