Combined gasification and chemical post-treatment
The pilot plant will be built in Umbria at one of the CE facilities within our warehouses. The selected plastic waste, supplied by PRT, will be gasified and transformed into DME (dimethyl ether).
The process will start from CSS (secondary solid fuel), a fuel produced from non-hazardous waste compliant with the European standard EN 15359 and normally destined for cement factories or waste-to-energy plants. The type of CSS used in the demonstrator is obtained from non-recoverable plastic, collected through separate waste collection by the Corepla consortium, a platform owned by PRT. Plastics from separate collection are processed with a cutting-edge system by PRT, in such a way as to recycle as much as possible, leaving a non-recyclable compound, CSS.
The expected composition of the feedstock is, as per analyzes carried out by the CSM : 66.6 wt% plastic materials (40.7 wt% LDPE, 8.1 wt% PP, 6.7 wt% PET and 11.1 wt% HDPE), 26.0 wt% rubber, 0.4 wt% wood, 0.3 wt% leather and 6.7 wt% other materials.
The conversion of CSS into syngas will be carried out through a gasification process owned by the Chemical Empowering at high temperatures (~900 °C), low residence times and in an atmospheric pressure. Water vapor will be used to guarantee a good ratio H2/CO and an overall cleaner syngas.
The gasification of CSS can be schematized in the following phases: (1) pyrolysis, (2) oxidation and (3) reduction.
In the first phase, flash pyrolysis occurs rapidly and with short contact times to reduce the reformation of intermediate compounds. To favor the production of the gaseous fraction, pyrolysis occurs above 650 °C in less than a second.
In the second and third phases, oxidation and reduction reactions take place so that all the material can be gasified.
Once CSS has been gasified, the syngas will be cooled by recovering electrical energy through our Heat to Energy system, which is composed of a turbo expander and a thermoelectric system. The cooled gas will be then passed into the induction torch and at the same time it will vitrify the ash and clean the TAR. Finally, the gas will undergo a wet cleaning and the water will be recycled through our Empowering Device system.
The gas will be continuously monitored via sensors, evaluating its temperature, pressure and composition. If sulfur compounds are still present, these would be eliminated from the syngas via an iron oxide rat. After this stage, the syngas is ready to enter the ZEB reactor.
The subsequent synthesis of DME from the syngas will be favored by an innovative bifunctional catalyst from CNR. The ZEB is a particular chemical reactor with a semi-rewardable membrane which allows the elimination of the reaction water and favors the formation of the DME, the latter once formed will be purified and bottled.
The PLASTICE project also involves the conversion of DME into olefins via a catalyst designed by the CNR, starting from a non-recyclable waste material we would have a product with high added value, closing the circle and giving new life to a waste material.
