CO2 Separation for Biomethane Production
and Flue Gas Treatment
Processes and Technologies of HZI BioMethan GmbH, Zeven
March 2016
Contents
1
From Biogas to Biomethane
2
Amine Scrubbing Process
3
Membrane Technology Process
4
CO2 Separation in Flue Gas
5
Biomethane Filling Station
6
Use Cases
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
1) Biogas, Biomethane and Their Uses
Biogas is created through the digestion of biomass.
It is a flammable mixture of 50-70% methane and 30-50% carbon dioxide (CO2).
It also contains various trace gases, including nitrogen, ammonia, and hydrogen sulfide.
Biogas is upgraded to biomethane (equivalent in quality to natural gas) by separating the
CO2.
It can then be fed into the natural gas grid for use in a wide range of different
applications.
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
1) The Biomethane Value Chain
Source: HZI Kompogas
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
1) The Biomethane Value Chain
Source: dena
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
1) Uses
Source: HZI
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
1) European Plants
200
140'000
180
180
120'000
115'000
160
100'000
140
120
80'000
100
60'000
80
60
54
40'000
28'500
40
20
23
11'900
20'000
15
4'175
11
2'800
64'130
52'730
4
0
8'650
3
3 850
2 0
1 0
4'000
1
0
0
Number of Plants
Production Capacity in Nm³/h
Source: energie / wasser-praxis 02/2016
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
2) Pressureless Amine Scrubbing
Highly efficient and reliable heat-driven
process
Standard volumes: 125, 250, 500, 700,
1,000, 1,400, 2,000 m³/h
Methane slip < 0.1%
Biomethane purity > 99%
Outlet pressure 0.1-0.15 bar
A chemical scrubbing solution binds the
CO2 and separates it from the biogas.
The scrubbing solution is recycled and fed
back into the process.
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
2) Amine Scrubbing Process Diagram
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
2) Amine Scrubbing
CO2 separation
The reaction surface is maximized in the scrubbing
column.
The biogas flows upwards from the bottom.
The scrubbing solution is fed in from the top.
The loaded scrubbing solution is drawn off from
the bottom of the column.
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
3) Membrane Technology
Pressure-driven process with
membrane-based gas separation
Evonik Sepuran® membranes made of
high-performance polyamide plastics
Standard volumes: 125, 250, 500, 700,
1,000, 1,400, 2,000 m³/h
Under pressure, the membranes hold
the methane back but allow the CO2 to
permeate through.
Methane slip < 0.5%
Biomethane purity > 97%
Outlet pressure 6-16 bar
Membrane solutions are suited to
smaller and fluctuating biogas flows.
Photo: Evonik
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
3) Membrane Technology Process Diagram
1
2
3
4
5
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
3) Membrane Technology
CO2 separation through selective permeation
Biogas flows under pressure into the membranes (the process requires a pressure of
10-16 bar).
CO2 = permeate
CH4 = retentate, drawn off at end of module
CH
4
CO
2
NH
3
HS
2
HO
2
Biogas
Methane
Retentate
CO
Permeate
2
Membrane
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
3) Membrane Technology
Membrane separation takes place in three stages:
In the first stage, the pre-cleaned raw biogas feed is separated into methane-enriched
retentate and CO2-containing permeate.
This is followed by two stages of refining to achieve the desired biomethane purity and
maximize the methane yield.
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
3) Process Comparison
Amine scrubbing
Membrane technology
Functional principle
Chemical absorption
Physical, permeation
Electricity demand
0.1 kWhel/m3
0.25 kWhel/m3
Heat demand
0.6 kWhth/m3
-
Biomethane purity
> 99%
> 97%
Methane slip/loss
< 0.1%
< 0.5%
Outlet pressure
0.1-0.15 bar
6-16 bar
Standard volumes
125, 250, 500, 700, 1,000, 1,400,
2,000 m3/h
125, 250, 500, 700, 1,000, 1,400,
2,000 m3/h
Cost of consumables
EUR 30,000 to replace amine
solution every 3 years
EUR 250,000 to replace membrane
modules every 3 years (700 Nm3/h
plant)
Decisive factors in choice of process
• Low-cost heat source available
• High biomethane purity required
• High CO2 purity required
• Complies with LNG requirements
• Low, predictable electricity costs
• Small, fluctuating biogas flows
• High outlet pressure required
• Complies with CNG requirements
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
4) CO2 Separation in Flue Gas
Treatment of flue gases from industrial
processes
Example: HBB Holzbearbeitung Bralitz GmbH
Energy from waste wood in a wood-fired power
plant: the ORC plant generates electricity from
the heat energy in the flue gases.
The HZI BioMethan amine scrubbing process
is used to treat some of the flue gases and
separate the carbon dioxide they contain.
The CO2 is stored in a spherical tank.
It is then supplied to a nearby greenhouse,
making for an economical and environmentally
friendly solution.
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
5) Biomethane Filling Station
Example: bioCNG M 125 m³/h
Housed in a 45-foot container
Raw biogas cooling, pre-compression and activated carbon filter for outdoor installation
External dispensing unit and flow meter
Space requirement: approx. 60 m2
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
5) Biomethane Filling Station
Example: bioCNG M 700 m³/h
Membrane technology housed in 40-foot
container
CNG technology in additional 20-foot
container
Raw biogas cooling, pre-compression and
activated carbon filter for outdoor
installation
External dispensing unit and flow meter
Space requirement: approx. 150 m2
Overhead view, BioFuel 700 m³/h
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
5) CNG Supply Costs
Comparison between CNG and bioCNG
1.40 €
1.32
EUR/kg
1.20 €
1.04
0.95
1.00 €
0.80 €
0.82
0.60 €
0.55
0.40 €
0.20 €
125 Nm³/h
CNG Referenzpreis
kg CNG @ 5,00 €‐cts/kWh Biogas 700 Nm³/h
kg CNG @ 2,00 €‐cts/kWh Biogas CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
5) Biomethane Filling Station: Summary
Upgrading from biogas to bioCNG technically possible
Ideal combination of efficient membrane separation and proven
(high-pressure) compressor technology
Broad capacity range covered: 50-700+ m³/h (RBG)
Reliable pre-treatment of raw gas important, in particular for gas
from landfills, waste and sewage
Most important criterion in plant design: type and number of
vehicles to be fueled
Key economic factor: raw gas production costs
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References / Schwedt
Feed-in capacity: 700 Nm³/h
Input: liquid manure, dry chicken
dung, agricultural products
Commissioned: 2011
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References / Winterthur
Feed-in capacity: 250 Nm³/h
Input: 23,000 t biological waste
p.a.
Commissioned: 2014
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References / Berlin under license
Source: BSR
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References / Karft
Feed-in capacity: 700 Nm³/h
Input: industrial and
slaughterhouse waste
Commissioned: 2011
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References / Werlte / Audi e-gas project
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
6) References / Werlte / Audi e-gas project
Input power:
6,300 kWel
H2 output:
1,300 m³/h
e-gas output:
300 m³/h
CO2 source:
CO2 exhaust gas from biogas treatment plant
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016
Thank you for your attention
CO2 Separation for Biomethane Production and Flue Gas Treatment, HZI BioMethan GmbH, March 2016