A newly developed gasification process utilises waste plastics, carbon-containing sorting residues and rubber parts as well as shredded materials from the automotive industry.
The system can also process chlorine-containing plastic streams with PVC fractions in an environmentally friendly and efficient manner. It produces a purified syngas without flue gas emissions.
In the process, lime serves as a transport medium and simultaneously binds halogens and other harmful substances. The gas generated in the shaft kiln can replace valuable primary energy sources such as natural gas in high-temperature processes or be used to generate electricity in efficient gas engines.
The process utilises diverse residues, including problematic plastic wastes or contaminated materials, without them having to undergo complex processing in advance. Potential feedstocks include sorting residues from recycling bins, heavy and light fractions of shredded materials, plastic composites or contaminated waste wood, miscellaneous biomass, roofing felts, lignite, salt coal, oil shale, tar lakes, contaminated soils, bituminous waste and, in particular, sewage sludge.
Some waste, such as sewage sludge or plastic-containing e-waste fractions, contains valuable materials such as phosphorus, precious metals and rare earths. These can be enriched, separated and recycled by binding them with fineground lime.
Roland Möller, head of the research project and Director of the Ecoloop company, says: “We make gas from waste. Our technology does not have to limit the use of chlorine-producing feedstocks for the combustion processes as is usually the case. With Ecoloop we want to supplement the waste and recycling technology in a sensible manner.”
The energy efficient utilisation of plastic waste in the new gasification plant provides a cheap alternative to incineration in waste incinerators with the subsequently necessary flue gas cleaning.
Syngas is produced in the shaft kiln
The furnace plant combines proven technical systems and methods that mainly stem from the lime industry to provide an innovative, flexible recycling process.
Here the residues are mixed with coarse-ground lime and converted into syngas in a bulk material moving bed using the counter flow principle.
The moving bed gasifier system does not require complex rotating parts or fixtures that are susceptible to damage. Under its own gravity, the material is transported from top to bottom in a bulk material moving bed comprising lime and substitute fuels, just as in the lime burning process.
Read the full report on K-online.