TWT in the Centre of Circular Economy – Roxyfuel for Energy-Saving CO₂ Delivery

The Roxyfuel-process uses the recirculation of flue gas with an addition of oxygen, so that the nitrogen in the flue gas gets substituted by CO2. With a concentration of about 85 Vol.-% of CO2 in the flue gas the compression and separation of CO2 gets very efficient especially considering about the later needed compression for transport.

by Ragnar Warnecke

Thermal Waste Treatment plants (TWT) are an important part of the circular economy. They are concentration machines for any kind of material and are able to use the inherent energy of the material. The energy using under a very high degree of efficiency is standard. The recovery of materials at present concentrates on metals. To increase the material recovery the ongoing projects lead to the substitution of raw materials for cement and concrete industry by the minerals especially in the bottom ash. In the future also the contaminants in the flue gas residues should be recovered for they can be used for similar products again in which they had been part of when entering the TWT. The main recovery mass flow can be CO2 from the flue gas. Different kinds of processes are mentioned and the compression process is recommended to be very efficient in relation to the other carbon capture processes, especially when it is combined with the Roxyfuel- (or Roxywaste-) process. The Roxyfuel-process uses the recirculation of flue gas with an addition of oxygen, so that the nitrogen in the flue gas gets substituted by CO2. With a concentration of about 85 Vol.-% of CO2 in the flue gas the compression and separation of CO2 gets very efficient especially considering about the later needed compression for transport. Although this process is efficient there are several boundary conditions listed to be fulfilled before the realisation can be successful – i.e. for example clearness about the transport of CO2 and the whereabout of CO2.

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published: , 4|2025
Keywords: Energy Recovery, Pollution Control, Resource management, Mixed Waste