FLASH PYROLYSIS RECYCLING ORGANIC WASTE, TYRES & PLASTICS INTO OIL AT BASQUE COU
The Department of Chemical Engineering of the UPV/EHU-University of the Basque Country has developed fundamental processes for producing raw materials and fuels using biowastes and tyres.
According to the university, the group led by Martín Olazar, a researcher in the UPV/EHU's Department of Chemical Engineering, is studying the development of sustainable refineries where it is possible to produce fuels and raw materials providing an alternative to petroleum by using organic waste and other waste materials such as plastics, tyres, etc.
The university went on to explained that the key to the high energy efficiency of the refineries is conical spouted bed technology.
Olazar, a UPV/EHU chemical engineer, designed the fundamental process which uses a reactor based on conical spouted beds which, by means of flash or rapid pyrolysis, produces fuels and raw materials using various types of waste – without harming the environment.
The researcher has developed two lines, depending on the type of waste. One uses biomass as a feedstock and the other plastics, tyres and similar waste.
The first uses agricultural waste and biomass from forests. According to Olazar, 70% of the mass treated can be turned into bio-oil, which he said “means that if we process a tonne of biomass, we can obtain 700 litres of bio-oil.”
The process to produce bio-oils is based on flash pyrolysis.
"This is very rapid pyrolysis,” explained Olazar. “We can produce it in 20 milliseconds at a low temperature (500°C) so high energy consumption is not required."During pyrolysis the biomass is degraded and the compounds produced can be rapidly extracted. If they are not extracted quickly Olzar said that they start to react among themselves and produce “things we are not interested in”.
The compounds produced when the biomass is degraded are extracted and condensed, and bio-oil is produced.
"It is a biological oil, so to speak," asserted Olazar, who added that the quality of bio-oil is lower than that of petroleum based oil because it contains oxygen and has to be treated.
However, Olazar stressed that it can be used to produce any petroleum by-product: hydrogen, olefin derivatives, aromatics, etc. He also pointed out that the bio-oil process is much more efficient than the biodiesel process.
"To produce biodiesel, a specific plant needs to be grown and a very small percentage of it is taken advantage of. Only 10% of the mass used is turned into biodiesel, whereas we use whole plant waste and obtain 70%," said the researcher.
The Basque Country University noted that the reactor has already been patented and a pilot facility has been put into operation in collaboration with the IK4-IKERLAN research centre. The promoters of the project are planning to open a larger facility in the future.
Carbon black from tyres
In addition to the biomass project, Olazar has also designed a reactor to produce materials very similar to the original feedstock using waste plastics and tyres, etc. This is claimed to be particularly efficient in the treatment of tyres:
"When flash pyrolysis is carried out under specific conditions, we can produce some very interesting raw materials, like carbon black," said Olazar.
Carbon black is the main raw material used to manufacture tyres. In the sustainable refinery, the processing of used tyres is said to turn 30% of the waste into carbon black.
"A high enough percentage for it to be profitable," Olazar noted.
Apart from carbon black, the material produced by the process, which can operate continuously, is said to have a host of applications as an adsorbent. The (liquid) remainder can also be put to various uses.
"It is a unique reactor in its class,” concluded Olazar. “We have patented it and we want to start up a medium-sized unit.”
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