RaakPro Bio P2G

  • looptijd: 2014 - 2017
  • locatie: Utrecht, Utrecht
  • functie: Waterstof

Studie naar accelerator technologieën voor biovergisting. 

Dit RaakPRO programma onderzocht of Power-to-Gas (P2G) met behulp van biologische methaanvorming (Bio-P2G) technologisch en economisch aantrekkelijk is als bijdrage aan het op elkaar afstemmen van vraag en aanbod van duurzame energie in Nederland.

De partners in dit project zijn het eens dat de oplossing die hier wordt voorgesteld, Power-to-Gas (P2G) met behulp van biologische methaanvorming (Bio-P2G), een waardevolle oplossing kan zijn als methode om meer en hogere kwaliteit methaan te maken als drager of opslag van duurzame energie.

RaakPro Bio-P2G

RaakPro Bio-P2G gebruikt elektriciteit om waterstof uit water te verkrijgen. De waterstof wordt vervolgens samen met kooldioxide omgezet in methaan. Dit proces gebruikt dus broeikasgas, kan leiden tot meer methaan uit biomassa en biedt een indirecte opslagmogelijkheid bij overmaat aan elektrische energie.

Zo kan Bio-P2G bijdragen aan een meer gedecentraliseerde aanbod van duurzame energie.

De chemische route voor P2G, bekend als de Sabatier-reactie, vereist grote gecentraliseerde installaties met hoge temperatuur en druk. Biologie zou het beter kunnen doen. Bacteriën kunnen waterstof en kooldioxide omzetten in methaan bij omgevingstemperatuur en druk. Bio-P2G is bewezen technologie op laboratoriumschaal.

Projectpartners

De samenwerkende partners in dit project waren: Hanzehogeschool Groningen, GasTerra, Gasunie

Contactpersoon

Jan-Peter Nap, j.p.h.nap@pl.hanze.nl

Betrokken wetenschappers

Professor Wim van Gemert, Hanzehogeschool

Subsidie: Raak Pro subsidie

Partners: 

raakpro

A new method of hydrogen administration

In Bio-P2G the excess of renewable electricity from wind turbines and solar panels is used for electrolysis of H2O to store energy as H2. Subsequently, this renewable H2 might be administered to an anaerobic digester to stimulate biological methanation by hydrogenotrophic methanogens. This research focusses on Hydrogen administration and the community change in the reactor as a result of H2 administration

Experimental design

Biological-methanation was studied at mesophilic conditions (42°C) in two 10 litre bioreactors (Infors) in an “in situ” setup, in which hydrogen was added directly to the CSTR in which AD was performed.

This bioreactor was equipped with a submerged 10-metre silicone tube, through which the hydrogen was added using a Mass Flow Controller (Bronckhorst®) to control the H2 addition.

Results

A clear difference of 28% was observed in the % of CH4 between reactor RH and reactor RC. This difference was accompanied by a decrease in CO2 in reactor RH.

Conclusion

  1. The setup makes use of the high permeability of siliconetubing: addition of 2 ml/min of hydrogen resulted in sufficient diffusion and solubilisation to convert the produced CO2 in the biogas by biomethanation.
  2. Furthermore, as expected, preliminary results with a newly developed Taqman assay clearly showed a relative increase of hydrogenotrophic methanogens compared to acetoclastic methanogens in the bioreactor in which hydrogen was added.
  3. Future experiments will also focus on development of an “ex situ” bioreactor setup, in which hydrogen and carbon dioxide will be added using silicone tubing
  4. On the reference model, a cost price of 72.1 €ct/Nm3 was obtained at an annual production of 2,400,000 Nm3/a of green gas, whereas this case study generated a price of 66.4 €ct/Nm3 of green gas at an annual production of 4,031,992 Nm3/a.

Link to the document

Is bio-P2G feasible from a techno-economic and sustainability point of view?

Methode

Concerning a reference biogas supply chain , the transformation blocks within the blue frame were replaced with transformation blocks resembling a biomethanation step.

For this adapted supply chain model, techno-economic parameters to model the new transformation blocks are determined from literature research. If parameters are not available from literature, experiments are suggested to find the information to fill the gap.

The cost price, energy efficiency and greenhouse gas reduction were calculated related to the biomethane produced. The model allows to study scale dependency of the biogas production and a variety of electrical input patterns.

  1. Although the cost price results show a reduction with regards to the reference model, the final price of the green gas is still subject to increase according to the expected need for equipment to stabilize the electrolyzer.
  2. Furthermore, this process relies on the availability of energy surpluses for its operation, which can be translated into operating hours per year.
  3. The less frequent the energy surpluses become, the lower amount of green gas will be produced and the more expensive it becomes.
  4. The same situation happens while studying the effect that the variation of the electricity prices would have within the process.
  5. The higher the price of the electricity, the more expensive the final gas becomes.
  6. Within this context, it is recommended to explore the effect that the establishment of a price for energy surpluses would have within the final price of the gas.