Large amounts of hydrogen are currently produced globally—94 million tonnes were produced in 2021 (equivalent to more than 3,000 TWh per year). The hydrogen is mainly used in the refining (42%) and chemical sectors, primarily for the production of ammonia (36%) and methanol (16%). A smaller share is used in the iron and steel industry and other applications (6%). Hydrogen demand in new applications such as transport, high- temperature industrial heat, directly reduced iron, and power and buildings only reached around 40,000 tonnes in 2021.1
Current hydrogen production is mainly based on technologies converting fossil fuels (more than 99%), primarily via steam reforming of natural gas (70%), while gasification of coal contributes approximately 30%. Less than 1% of the hydrogen produced from fossil fuels was from facilities equipped with CCS or CCU. Hydrogen produced via electricity and biomass barely met 0.2% of the total hydrogen production in 2021.2
Figure 1 shows a high-level overview of the essential processing steps included in converting carbonaceous feedstocks to hydrogen via thermal gasification.
Many gasifier types exist, but the most suitable technologies for hydrogen production are:
- Dual fluidized bed steam gasifier
- Oxygen-blown entrained flow gasifier
- Oxygen-blown fluidized bed
Gas Cleaning and Tar Removal
As in most applications, particulates and contaminants such as sulphur-, nitrogen-, and chlorine-containing components, as well as alkali metals, must be removed from the producer gas. Cyclones and filters can be used for bulk particulates removal, while wet scrubbing could be needed to remove fine particulates. Acid gas removal may also be required to remove the sulphur-containing gases and CO2. Hydrocarbons and tar must be eliminated via steam reforming, occasionally followed by additional scrubbing.
The WGS reaction is a key process to adjust the H2:CO ratio of the synthesis gas, depending on desired product. If hydrogen is to be produced, the WGS constitutes an important post- gasification operation to maximize the H2:CO ratio by further converting CO (and water) into hydrogen (and carbon dioxide).3
There are several commercially available processes to separate and purify hydrogen from synthesis gas. The most widely applied methods are amine scrubbing, pressure, or temperature swing adsorption techniques, as well as membrane systems enabling continuous and selective extraction of hydrogen.
The gas leaving the WGS typically contains 65–70 vol % hydrogen can be purified by PSA, producing a high-purity hydrogen stream (99.9%).4 With membranes, hydrogen can be directly extracted during the WGS reaction process.
Negative CO2 Emissions
CO2 is separated into a concentrated residual stream as an integral part of the process, thus providing a favourable source for CCS and consequently negative CO2 emissions. For every tonne of dry biomass gasified, about 0.1 tonnes of hydrogen can be produced with
1.7 tonnes of CO2, (i.e., 17 kg CO2 per kilogram of hydrogen).
Lower Costs for Carbon Capture
It is likely that the current development of technologies for CCS and CCU for applications other than gasification will lead to lower capital costs. As a result, the capture techniques may also be applied in smaller scales, which would be favourable for the economic performance of gasification processes that previously have been responsible for this development. Any progress made within CCU and CCS in other applications thus means more competitive gasification systems.
Non-Weather-Dependant, Fossil-Free Hydrogen Production
Gasification of biomass can be operated non-intermittently and at large scale.
Adding Hydrogen from Electrolysis to Synthesis Gas Increases the Product Yield and Carbon Efficiency
By supplying renewable hydrogen from electrolysis to syngas, the product yield can be significantly increased, as the CO2 in the syngas is also converted to products.5
Current Commercial Developments
There is, to the best knowledge of the Task 33 members, no commercial production of hydrogen via thermal gasification of biomass or waste in operation today. However, there are numerous ongoing plans and projects, including:
- The German company RWE plans for hydrogen production from gasification of residues in Limburg in the Netherlands. The project is one of 17 projects selected by the EU Innovation Fund to receive funding. Under the name FUREC (FUse REuse ReCycle), RWE aims to produce hydrogen for the chemicals industry.
- BrigH2 is a startup company developing a 50-MW demonstration plant on the Brightlands Chemelot Campus to produce hydrogen by gasifying torrefied biomass, based on technology developed by Torrgas in the Netherlands. Biochar will also be produced, which may be used as a soil improver.
- The U.S. company Mote announced its first production facility to convert wood waste into hydrogen fuel while capturing, utilizing, and sequestering CO2 emissions from the
Mote expects to produce approximately 700,000 tons of carbon-negative hydrogen annually. Mote expects to start hydrogen production in 2024.
- In the United Kingdom, KEW’s pressurised Advanced Gasification Technology (AGT) converts biomass into a hydrogen-rich synthesis gas and is demonstrated at commercial scale at its plant in Wednesbury. KEW is adding processes based on proven technologies to produce high-purity hydrogen as well as CO2 ready for
1 IEA. 2022. Hydrogen. Paris: IEA https://www.iea.org/reports/hydrogen.
3 J.G. Speight (Ed.). 2019. “Chapter 13 – Upgrading by Gasification.” In Heavy Oil Recovery and Upgrading, Gulf Professional Publishing, 559–614. https://doi.org/10.1016/B978-0-12-813025-4.00013-1.
4 M.A. Fahim, T.A. Alsahhaf, and A. Elkilani (Eds.). 2010. “Chapter 11 – Hydrogen Production.” In Fundamentals of Petroleum Refining, Elsevier, 285–302. https://doi.org/10.1016/B978-0-444-52785-1.00011-5.
5 Y. Jafri, E. Wetterlund, J.M. Ahlström, E. Furusjö, K. Pettersson, S. Harvey, and E. Svensson. 2021. Future-proof biofuels through improved utilization of biogenic carbon – Carbon, climate, and cost efficiency (k3). Report No FDOS 32:2022. https://f3centre.se/app/uploads/FDOS-32-2022_P48363-1_SR-220224.pdf.