INITIAL SITUATION
Thermal waste treatment produces CO₂ emissions that are difficult to avoid with current technologies. Instead of releasing all the carbon contained in waste as CO₂ during incineration, it could be kept in the cycle as a chemical feedstock – provided there is a process that can produce high-quality synthesis gas suitable for material use from heterogeneous waste.
The technological basis is circulating fluidised bed gasification (CFB gasification) using oxygen and steam, which is already commercially available for feedstocks such as coal and biomass. However, when waste is used as a feedstock, the quality of the synthesis gas produced is only partly suitable for material use: it contains a high proportion of hydrocarbons (including methane, ethene and tars). This is where the technical challenge lies – the raw gas must be treated so that basic chemicals such as methanol can be produced from it.
PROJECT OBJECTIVE
The aim is to develop a system for the thermochemical conversion of waste that converts more than 98% of the carbon bound in the waste into carbon oxides (CO and CO₂), making it available for further material use. To achieve this, downstream partial oxidation (POX) is integrated into the CFB gasification process. Using minimal oxygen and electrical heating, it converts the hydrocarbons, thereby increasing the H₂ and CO yields.
The complete system – CFB gasification of the waste plus partial oxidation of the raw gas – will be tested at laboratory and pilot scale (at TU Darmstadt’s 1-MWth pilot plant). Based on the results, an industrial plant will then be designed for permanent operation at MVV’s site in Mannheim. The goal is to reduce CO₂ emissions from thermal waste treatment there by more than 90% and achieve annual savings of over 175,000 tonnes of CO₂.
OUR SOLUTION
PlasmaAir AG is developing plasma technology for partial oxidation – the crucial stage that turns hydrocarbon-rich raw gas into high-quality synthesis gas.
Its contribution includes:
Qualification and further development of water-vapour-operated DC plasma sources for use in a POX unit.
Adapting the geometry for integration into a POX reactor – the plasma source is engineered to match the reactor.
Suitability for continuous operation – the plasma system is designed for uninterrupted industrial use.
Low maintenance, consumables and energy costs as key design criteria for ensuring economic viability at a later stage.
PlasmaAir therefore provides more than just a plasma source: it qualifies the electrically heated POX stage to the point where it can be scaled from laboratory and pilot level to a future industrial plant. The electrical heating of the oxidation stage is the key to increasing carbon yield in a climate-neutral way and moving the process towards closed material cycles.
