Boson Energy (€25M for biomass gasification)

Boson Energy develops solutions for clean, efficient, and affordable production of circular carbon-negative hydrogen from non-recyclable waste and biomass. They aim to create local, sustainable, and profitable ecosystems running on renewable hydrogen.

Challenges: biomass gasification

Hydrogen (H₂) is a “simple solution” to address the world’s energy problems and needs. The overall thermal efficiency of converting hydrogen to electric energy required by a fuel cell electric vehicle (FCEV) is three times greater than the thermal efficiency of burning this liquid fuel to power today’s internal combustion engine vehicles. Utilizing hydrogen in this manner may significantly contribute to global energy security.

Hydrogen must be separated from hydrocarbons (e.g., methane CH₄) or water (H₂O). The majority of the world’s hydrogen (over 60 million tonnes) is currently produced via steam methane reforming (SMR) process, which requires a significant amount of energy input and emits a substantial amount of carbon dioxide (CO₂). The SMR process emits between 5 and 9 tonnes of CO₂ per tonne of hydrogen produced.

Electrolysis of water by using renewable electric power produces green hydrogen without emitting CO₂. However, electrolysis requires 50 kWh of energy to produce 1 kg of H₂ which only gives 33 kWh of energy. 35% of the original input power is wasted. The cost of electrolysis-produced hydrogen is higher than that of SMR-produced hydrogen. In addition, the capacities of currently available electrolyzers are inadequate as they are useful for small scale production only.

Boson Energy Technology

Boson Energy has developed an efficient biomass gasification system that generates hydrogen-rich syngas through the use of a high-temperature gasifying agent and the chemical reaction between calcined lime (CaO) and CO₂.

The diagram below depicts Boson Energy’s biomass gasification system’s operation. The system comprises a high temperature gasifying agent generator, a gasifier, a reformer, a gas-solid separator (cyclone), and a regenerative combustor (calciner).

Boson Energy's biomass gasification system (ref. WO2009091325A1). — Boson Energy’s biomass gasification system (ref. WO2009091325A1).

The high temperature gasifying agent generator comprises a heat exchanger, a combustor, and a mixer. The heat exchanger heats the steam/air/oxygen gasifying agent to 1,200 ºC. In order to achieve a certain temperature for the gasifier, the steam/air/oxygen is mixed with 2,600 ºC exhaust gas from a fuel combustor. After mixing, the 1,600 ºC gasifying agent is injected from the bottom of the gasifier.

The biomass enters the gasifier from the top. The upward flow of high temperature gas heats biomass, which then descends to the bed of the gasifier. In the thermal decomposition of biomass, high-temperature gasifying agent promotes the steam reforming reactions and the formation of light gasses:

CₘHₙ + m H₂O → m CO + (m+n/2) H2

The produced gasses (such as CO, H₂, CH₄, light and heavy hydrocarbons) and solid materials (such as tar), as well as the surplus of steam, exit the gasifier at the top and enter the reformer with CaO injection. The reformer is run at 650 ºC. CaO captures over 90% CO₂ in the reformer:

CaO + CO₂ → CaCO₃ ∆H = −178 kJ/mol

The release of heat from the reaction reduces the amount of energy input required for the reforming reaction. Simultaneously, CaO’s capture reduces the CO₂ partial pressure. This promotes the water-shift reaction and steam reforming reaction, resulting the production of more H₂:

CO + H₂O → CO₂ + H₂ ∆H = −41 kJ/mol

CH₄ + H₂O → CO₂ + H₂ ∆H = 165 kJ/mol

Thus, a hydrogen-rich syngas is obtained.

The hydrogen-rich syngas and CaCO₃ pass through a gas-solid separator, resulting in pure hydrogen-rich syngas. The CaO can be regenerated by calcination at high temperature (900 ºC):

CaCO₃ → CaO + CO₂ ∆H = 178 kJ/mol

The heat for the calcination of CaCO₃ is supplied by combustion of a part of syngas. The calcined CaO sorbents are reused for CO₂ capture in the reformer.

The advantages of the Boson Energy’s biomass gasification system are:

The energy for biomass gasification to produce hydrogen-rich syngas is from heat of a high-temperature gasifying agent and the chemical reaction between CaO and CO₂. Thus, much less biomass needs to be burnt to supply the necessary energy compared to previous methods. Thus, the process can be run with a lower oxidant-to-fuel ratio, resulting in lower CO₂ and N₂ concentrations in the product gas and thus a higher heating value;
Enhanced heat transfer reduces the biomass’s residence time during the gasification process;
High content of hydrogen in the syngas;
Higher gas yields;
Lower tar contents; and
Lower soot and char residues.

Boson Energy Patent

WO2009091325A1 A biomass gasification method and apparatus for production of syngas with a rich hydrogen content
JP2011510115A Biomass gasification method and synthesis gas production apparatus with high hydrogen content
CN101932677A A biomass gasification method and apparatus for production of syngas with a rich hydrogen content
ZA201004824B A biomass gasification method and apparatus for production of syngas with a rich hydrogen content

Boson Energy Products

Boson Energy’s biomass gasification process can produce syngas with a high content of hydrogen and small amounts of tars. Per tonne of biomass, 80-120 kg/h of hydrogen can be produced with a fuel input of 3.5 MW. The standard annual unit treatment capacity is 5,500 tonnes. The site capacity can be scaled up by adding standard units.