Change search
ReferencesLink to record
Permanent link

Direct link
Pyrolysis of plastic waste for recovery of monomers and naphtha-like feedstock
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.ORCID iD: 0000-0002-1837-5439
(English)In: Journal of Waste ManagementArticle in journal (Other academic) Submitted
Abstract [en]

Pyrolysis of plastic waste is an alternative way of plastic recovery and could be a potential solution for the increasing stream of solid waste. The objective of this work was to increase the yield the gaseous olefins (monomers) as feedstock for polymerization process and to test the applicability of a commercial Ziegler-Natta (Z-N): TiCl4/MgCl2 for cracking a mixture of polyolefins consisted of 46 % wt. of LDPE, 30% wt. ofHDPE and 24 % of PP. Two sets of experiments have been carried out at 500oC and 650oC via catalyticpyrolysis (1% of Z-N catalyst) and at 650oC and 730oC via only-thermal pyrolysis. These experiments have been conducted in a lab-scale, fluidized quartz-bed reactor of a capacity of 1-3kg/h at Hamburg University. The results revealed a strong influence of temperature and presence of catalyst on the product distribution. The ratios of gas/liquid/solid mass fractions via thermal pyrolysis were: 36.9/48.4/15.7%wt. and 42.4/44.7/13.9%wt. at650oC and 730oC while via catalytic pyrolysis were: 6.5/89.0/4.5%wt. and 54.3/41.9/3.8%wt. at 500oC and 650oC, respectively. At 650oC the monomer generation increased by 55% up to 23.6 %wt. of total pyrolysis products distribution while the catalyst was added. Obtained yields of olefins were compared with the naphtha steam cracking process and other potentially attractive processes for feedstock generation. The concept of closed cycle material flow for polyolefins has been discussed, showing the potential benefits of feedstock recycling in a plastic waste management.

Keyword [en]
Fluidized Bed, Pyrolysis, Feedstock Recycling, catalysts, plastic waste
National Category
Metallurgy and Metallic Materials
URN: urn:nbn:se:kth:diva-34410OAI: diva2:421024
QS 2011 QS 20120326Available from: 2011-06-07 Created: 2011-06-07 Last updated: 2012-03-26Bibliographically approved
In thesis
1. Conversion of biomass and waste using highly preheated agents for materials and energy recovery
Open this publication in new window or tab >>Conversion of biomass and waste using highly preheated agents for materials and energy recovery
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

One of the greatest challenges of human today is to provide the continuous and sustainable energy supply to the worldwide society. This shall be done while minimizing all the negative consequences of the operation(s) to the environment and its living habitants including human beings, taking from the whole life cycle perspective. In this thesis work new solutions for treatment biomass and waste are analyzed.


Based on the fundamental research on the conversion of various materials (biomass: straw pellets, wood pellets; and waste: plastic waste, ASR residues after pyrolysis), converted by means of different systems (pyrolysis in a fluidized bed reactor, gasification in a fixed-bed reactor using highly preheated agents) it is recommended to classify materials against their charring properties under pyrolysis, in order to find the best destination for a given type of fuel. 


Based on phenomenological research it was found that one of the important effects, affecting performance of downdraft gasifiers, is the pressure drop through the bed and grate. It affects, directly, the velocity profile, temperature distribution and of the height of the bed, especially for the grate with restricted passage surface, although it was not investigated in literature. The lower grate porosity, the higher conversion of fuel and heating value of gas is produced. However, the stability of the process is disturbed; therefore reducing the grate porosity below 20% is not recommended, unless the system is designed to overtake the consequences of the rising pressure inside the reactor. This work proposed the method for prediction of a total pressure drop through the fixed-bed downdraft gasifier equipped with a grate of certain porosity with an uncertainty of prediction ±7.10.  


Three systems have been proposed; one for the treatment of automotive shredder residue (ASR), one for the treatment of plastic waste (polyolefins) and one for biomass (wood/straw pellets). Pyrolysis is an attractive mean of conversion of non-charring materials (like plastic waste) into valuable hydrocarbons feedstock. It gives directly 15-30% gaseous olefins while the residue consisting of naphtha-like feedstock has to be reformed/upgraded to olefins or other chemicals (e.g. gasoline generation) using available petrochemical technologies. Pyrolysis of complex waste mixture such as ASR is an attractive waste pretreatment method before applying any further treatments, whereby useful products are generated (gaseous and liquid fuel) and char, rich in precious metals. The solid residues are meant for further treatment for energy and metals recovery. Gasification is a complementary method for handling pyrolysis residues. However, metals can be removed before gasification. Pyrolysis of charring materials, like biomass, is a very important step in thermo-chemical conversion. However, the char being approximately 25%wt. contains still very high caloric value of about 30MJ/kg. This in connection with the High Temperature Steam Gasification process is a very promising technology for biomass treatment, especially, above 900oC. This enhances the heat transfer towards the sample and accelerates kinetics of the gasification. This, in turn, improves the conversion of carbon to gas, increases the yield of the producer gas and reduces tar content. At higher steam to fuel ratio the process increases the yield of hydrogen, making it suitable for second-generation biofuels synthesis, whereas at lower steam to fuel ratio (S/F<2) the generated gas is of high calorific value making it suitable for power generation in a combined cycle.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. 115 p.
biomass, waste, pyrolysis, gasification, ASR
National Category
Metallurgy and Metallic Materials
Research subject
SRA - Energy
urn:nbn:se:kth:diva-34253 (URN)ISBN 978-91-7501-033-5 (ISBN)
Public defence
2011-06-15, D3 (entreplan), Lindstedtsvägen 5, KTH, Stockholm, 10:00 (English)
QC 20110607Available from: 2011-06-07 Created: 2011-05-30 Last updated: 2011-12-12Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Donaj, Pawel J.Yang, Weihong
By organisation
Energy and Furnace Technology
Metallurgy and Metallic Materials

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 133 hits
ReferencesLink to record
Permanent link

Direct link