11.0 - Methane capturing.ppt 5840KB Mar 29 2010 05:00:30 AM
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
11.1 Types of extraction systems
11.2 Operational aspects
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
Three main factors influence the migration of landfill gases:
Pressure
Permeability and
Diffusion
5/27
11 – Methane capturing
11.1 Types of extraction systems
Landfill gas extraction
Landfill gas is:
explosive in air
a Greenhouse Gas (GHG) and
toxic to humans
….and therefore should be controlled on landfills
6/27
11 – Methane capturing
11.1 Types of extraction systems
Landfill gas extraction
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
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
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
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
Monitoring
equipment
Anemo meter
Digital manometer
Gas analyser
21/27
11 – Methane capturing
11.2 Operational aspects
Landfill gas monitoring
Gas
analyser can measure:
1.
CH4
2.
CO2
3.
O2
4.
N2 (= 100% - CH4% - CO2% - O2%)
22/27
11 – Methane capturing
11.2 Operational aspects
Landfill gas monitoring
If
CH4 and O2 concentration respectively in a gas
well is:
> 50% and < 1% then
more extraction
< 50% and > 1% then
less extraction
23/27
11 – Methane capturing
11.2 Operational aspects
Landfill gas monitoring
If
N2:O2 ratio is:
>5
indicator suction of ambient air
11 Methane capturing
1
1/27
11 – Methane capturing
“Landfill gas extraction system in the making”, Braambergen landfill
2/27
11 – Methane capturing
Overview
11.1 Types of extraction systems
11.2 Operational aspects
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
Three main factors influence the migration of landfill gases:
Pressure
Permeability and
Diffusion
5/27
11 – Methane capturing
11.1 Types of extraction systems
Landfill gas extraction
Landfill gas is:
explosive in air
a Greenhouse Gas (GHG) and
toxic to humans
….and therefore should be controlled on landfills
6/27
11 – Methane capturing
11.1 Types of extraction systems
Landfill gas extraction
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
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
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
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
Monitoring
equipment
Anemo meter
Digital manometer
Gas analyser
21/27
11 – Methane capturing
11.2 Operational aspects
Landfill gas monitoring
Gas
analyser can measure:
1.
CH4
2.
CO2
3.
O2
4.
N2 (= 100% - CH4% - CO2% - O2%)
22/27
11 – Methane capturing
11.2 Operational aspects
Landfill gas monitoring
If
CH4 and O2 concentration respectively in a gas
well is:
> 50% and < 1% then
more extraction
< 50% and > 1% then
less extraction
23/27
11 – Methane capturing
11.2 Operational aspects
Landfill gas monitoring
If
N2:O2 ratio is:
>5
indicator suction of ambient air