(61d) Catalytic Plastic Pyrolysis and Steam Cracking an Opportunity for a Win-Win Partnership

Anellotech has spent the last 12 years building a scalable advanced biofuel and chemical recycling
suite of technologies that can dramatically reduce greenhouse gas emissions of transportation
fuels or plastic manufacturing including packaging and textiles. The company’s unique patented
catalytic cracking and pyrolysis Plas-TCatTM process approach combines expertise in fluid bed
reaction engineering and catalysis with solids handling and pretreatment of waste plastic
feedstock materials for direct production of light olefins (C2, C3, C4) and BTX. This paper
presents the current stage of Plas-TCat development (TRL-6) with large pilot plant demonstration
in the expected commercial-scale olefins production environment.
Floods, droughts, everyday news confirm that climate change happens, and we need to handle.
Furthermore, ocean pollution and microplastic issue concern people. The growing market pull for the
products with a low CO2 footprint confirm people awareness of this fact. Usually, such developments are
followed by regulatory actions either in form of incentives or taxes. Circular economy is one of the options
to address, above mentioned, changing market and environmental needs but also an opportunity to make
money (develop new business area). Therefore, plastic recycling became in the last few years an increased
interest expressed in the development activities and investments in new recycling plants. However,
technologies available on the market can’t solve the recycling problem due to their limitations with
respect to the voluminal and plastic waste composition.
Chemical recycling is one of the advanced answers to the future market needs. Currently chemical
recycling, i.e. conversion of waste plastics to monomers or chemicals, is dominated by the gasification and
thermal pyrolysis processes. Both technology families need multistage processing in order to obtain basic
feedstock olefins and aromatics and to close the recycling loop. The gasification route is an especially long
processing chain and CAPEX intensive technology. In the case of thermal pyrolysis, its product, i.e., pyoil
can be fed either to FCC units or to steam cracker (“SC”) furnaces. However, when using it as SC feedstock
it needs to be deeply pretreated in order to remove heteroatoms and contaminates. It is also a low quality
feedstock because of its highly olefinic composition which promotes coking in the cracking furnaces.
Alternatively, Plas-TCatTM ’s catalytic pyrolysis of plastic wastes belongs to the second generation
technologies for conversion of plastic wastes which overcomes disadvantages of gasification and thermal
pyrolysis. Catalytic pyrolysis integrates thermochemical decomposition of plastics with in-situ catalytic
conversion of pyrolytic intermediates directly to high value chemicals, i.e. aromatic hydrocarbons (mainly
BTX) and light olefins (mainly C2, C3 and C4). Catalytic transformation also eliminates heteroatoms from
the liquid product stream by conversion to components that can be easily separated from the product
gas. The ability to remove heteroatoms allows this process to convert mixed plastic waste streams that
contain all types of plastics (1-7) with exception of PVC. Combining the expected emission reductions
of the direct conversion process with the scalability of fluid bed processing can deliver large CO2
mass reductions for the world’s transportation and chemical manufacturing sectors that are
consistent with the olefins industry GHG reduction goals.
Since it is a low pressure and relatively low temperature process it exhibits also competitive CAPEX. As for
most chemical processes it is important to achieve economy of scale. Catalytic pyrolysis offers the
possibility to scale the process to large units since it converts plastics in a fluidized bed reactor that utilizes
the same principles as FCC reactors. However, the maximum capacity of a catalytic pyrolysis plant
currently is limited by the logistic costs for the PSW supply. This limitation is especially critical for CAPEX
of product separation. One of the possibilities to reduce the downstream costs is an integration with a
large-scale units like FCC or Steam Crackers. By this linkage with existing units the catalytic conversion can
profit from the economy of scale. On the other side, by integration of the catalytic pyrolysis with Ethylene
Plant downstream purification trains, the olefin producers can reduce their CO2 footprint and offer plastic
waste-based monomers along with their virgin olefins supply to PE, PP, etc. downstream units without
affecting the steam cracking furnaces except for small paraffin recycling needs.
In the presentation, a catalytic pyrolysis process, developed by Anellotech, Inc., for conversion of mixed
plastics wastes (Plas-TCatTM) will be introduced. This development is at the stage of testing and validation
(TRL-6) in a large fully automatized and continuously operated pilot plant with a nameplate capacity of
0.5 t/d. Furthermore, the potential for integration of Plas-TCat with a steam cracker plant will be
discussed.