Discussion

1
Agenda

• Welcome
• Presentation
• Discussion
• Evaluation
• Closing

2
Biogas upgrading

• Jos de Hullu
• Jenny Maassen
• Paul van Meel
• Siamak Shazad
• Jessica Vaessen
• Tutor Laura Bini
• Project coordinator Jetse Reijenga

3
Outline

• Biogas
• Upgrading techniques
• Boundaries
• Chemical absorption
• Water scrubbing
• Pressure swing adsorption
• Cryogenic separation
• Membrane separation
• Comparison
• Conclusions
• Outlook
• Questions

4
What is biogas?

• Combustible gas mixture (CH4, CO2, H2S)
• Anaerobic fermentation preferred
• Upgrading biogas
• Increasing calorific value
• Stripping CO2 and H2S
• Input 250 m3/hr
• Injecting in gas grid

5
Biogas demands
6
Outline

• Biogas
• Upgrading techniques
• Boundaries
• Chemical absorption
• Water scrubbing
• Pressure swing adsorption
• Cryogenic separation
• Membrane separation
• Comparison
• Conclusions
• Outlook
• Questions

7
Boundary conditions

• Simple model, only main parts are discussed
• Waste streams are not modeled but are considered
• The model starts with untreated biogas
• The total input of energy and materials will be
  investigated
• Costs of operating and investment will be
  estimated and be used to calculate the price per
  m3 of exit gas

8
Chemical absorption PFD
9
Chemical absorptionAdvantages Disadvantages

• Disadvantage
• Scrubber needed to remove CO2
• Advantages
• Almost complete removal H2S
• H2S converted into S

10
Water scrubbing PFD
11
Water scrubbing Advantages Disadvantages

• Disadvantages
• High amounts of H2S cannot be stripped
• H2S is corrosive and will damage the scrubber
• Advantages
• High purity of CH4 can be reached
• Removes both gases and particulate matter
• Neutralization of corrosive gases

12
Pressure swing adsorption PFD
13
Pressure swing adsorption Advantages
Disadvantages

• Disadvantage
• H2S has to be removed prior to PSA
• Advantages
• High CH4-enrichment
• Low power demand
• Low level of emission

14
Cryogenic separation PFD
15
Cryogenic separation Advantages Disadvantages

• Disadvantage
• A lot of equipment needed
• Advantages
• Large quantities with high purity produced
• No use of chemicals
• Easy scale up

16
Membrane separation PFD
17
Membrane separation Advantages Disadvantages

• Disadvantages
• Membranes are expensive
• Fouling
• Advantages
• Compact and light in weight
• Low maintenance
• Low equipment costs
• Low energy costs

18
Comparison

• Chemical absorption gives a total removal of H2S
  but requires a scrubber for CO2 removal.
• Water scrubbing is easy and has been proven
  profitable.
• PSA is a rather complicated process but gives
  good results in practice.
• Cryogenic separation will probably be very
  expensive and only profitable for high biogas
  streams.
• A membrane plant is very easy to operate but
  could be expensive.

19
Outline

• Biogas
• Upgrading techniques
• Boundaries
• Chemical absorption
• Water scrubbing
• Pressure swing adsorption
• Cryogenic separation
• Membrane separation
• Comparison
• Conclusions
• Outlook
• Questions

20
Conclusions

• Overview different techniques
• Waste streams
• Maintenance

21
Outlook

• Cost estimation
• CO2 footprint
• Cryogenic separation in model
• Comparison

22
Questions
23
Outlook