Waste Becomes Hydrogen

Hydrogen is an important energy source for the transformation of the energy system. Within fuel cells, it can be converted into climate-friendly electricity and heat. Researchers from Siegen have developed their own gasification process for generating a hydrogen-rich gas from waste.

Scrap and waste wood, treated municipal waste or waste from car recycling – the developers have already tested various materials. The waste is used to produce a "designer fuel", which ensures that the quality of the producer gas is consistent. Compared to the traditional method of hydrogen production, the "ReEnvision" project saves 90 per cent of CO2.

With the ReEnvision project (abbreviation of ”regenerative energy vision”), researchers have developed their own gasification process to generate a hydrogen-rich gas from secondary fuels (waste). The gasification process was successfully developed and operated at the pilot plant at the University of Siegen (100 kW). Hydrogen for fuel cells and metallurgical applications is separated from the synthesis gas. The developers have already worked with several fuels such as scrap and waste wood, treated municipal waste or waste from car recycling. A special treatment process transforms the waste into a "designer fuel", which ensures that the quality of the producer gas is consistent.

Engine for progress:

  • green production of a hydrogen-rich gas mixture
  • wide range of applications for various secondary fuels
  • overall efficiency of 62 per cent including the recovery of waste heat
  • more than 90 per cent CO2 savings compared to conventional methods
  • possible to operate with almost no waste water

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Photo: Sicon GmbH

90 per cent CO2 savings possible: Gasification is significantly more eco-friendly and effective

Worldwide, highly calorific waste materials with heating values comparable to those of coal are, to a large extent, still being dumped in landfills. In Germany, for example, thermal recycling, i.e. the burning of these materials, is legally prescribed. This is done in conventional waste incineration plants using grate firing. However, the energy content of the fuels, with an efficiency level of about only 10 per cent, is converted into electricity. If the residual materials were to be gasified, the hydrogen separated from the producer gas and the residual gas converted into electricity in a gas engine, the efficiency could be more than tripled – a significant environmental improvement compared to the current state-of-the-art technology.

The overall efficiency of the ReEnvision plant is 51 or 62 per cent (with the utilisation of waste heat). Climate-damaging emissions from landfilling and incineration can be significantly reduced with the help of the process. Compared to the classical procedure of "steam reforming" to produce hydrogen, ReEnvision saves 90 per cent of CO2.

60 plants in Germany are conceivable, 36,000 tonnes of hydrogen per year are possible.

ReEnvision GmbH is planning the construction of a five-megawatt demonstration plant. The hydrogen separation and filling station are to be a direct integral part of the system. During operation, important findings should be gained for the subsequent industrial distribution and provision of hydrogen from secondary fuels.

600 tonnes of hydrogen can be produced per year at a 20-megawatt industrial plant. In addition to applications in the transport sector, applications in the field of metallurgy are also conceivable, for example as a reducing agent in the production of steel. In the business plan, the potential in Germany alone is stated at 60 large-scale (20 MW) plants. Worldwide, there is potential for over 500 plants.

Technical background:

The technical basis for ReEnvision is an upstream, two-stage synthesis gas production process using the so-called IPG procedure (Integrated Pyrolysis and Gasification). The principle is based on spatial separation of pyrolysis and the energy required for this. The process the IPG gasification technology builds on is new and initially a fixed-bed reactor and a fluidised bed reactor are being operated in parallel.

The fuel pyrolysis takes place under reducing conditions in a fixed bed and the resulting residual coke is burned in the fluidised bed. The inert (low reaction) parts of the fuel and the ashes resulting from the combustion process are used as circulating heat carriers. The material is heated in a fluidised bed reactor using residual coke combustion. The procedure can be operated with almost no waste water.

Photo: Sicon GmbH

"To date, the waste management industry has relied heavily on energy recovery from waste and secondary fuels. The decentralised production of fuel and hydrogen in particular opens up new perspectives for regional and resource-efficient waste management." (Photo: SICON GmbH)

Heiner Guschall, Managing Director of SICON GmbH

Partners and sponsors

  • ReEnvision GmbH
  • Universität Siegen, Lehrstuhl für Energie- und Umweltverfahrenstechnik