hydrocracking plastic mixtures into xylene (or btx) chao
TRANSCRIPT
Hydrocracking Plastic Mixtures into Xylene (or BTX)Chao Wang, Johns Hopkins UniversityTeam Members: Michael Tsapatsis (JHU)
We target catalytic upcycling of end-of-life hydrocarbon plastics into value-added, liquid aromatic chemicals such as benzene, toluene and xylene (BTX).
Total Project Cost: $1MLength 18 mo.
Project Vision
Award #: DE-AR0001362(2/23/2021 - present)
The Concept
▸ Chemical recycling of HDPE has been extensively studied
– Thermal pyrolysis– Light hydrocarbons/broad
distributions
▸ #3-7 plastic mixtures represents one of the cheapest plastic waste stream
– PVC (#3), LDPE (#4), PP (#5), PS (#6) and others (#7, including acrylic, polycarbonate, polylactide, etc.)
▸ Possible valuable products from depolymerization of plastics
– Xylene (>$20/MMBtu)– Aromatics (>$15/MMBtu)
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The Team‣ PI: Chao Wang (ChemBE, JHU)
– Catalyst development– Catalytic studies– Reactor design– TEA
‣ Co-PI: Michael Tsapatsis (ChemBE, JHU)– Catalyst development– Process engineering– Product separation and purification
‣ T2M: Stephen Goff (previously with Covanta)– Pre-engineering design for pilot facility– Industrial partnership development
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Project Objectives‣ We target energy-efficient and economically upcycling of low-cost
#3-7 plastic mixtures ($5/ton) into BTX (~$1,000/ton).
‣ Timeline– Bench-scale proof of concepts accomplished by the end of
2021– Demonstration of continuous hydrocracking
• 1 kg/day reactor is currently being built up at Hopkins (operation by Jan 2022)
– Pre-engineering design for pilot plant (T2M)• Pilot facility designed for 1 ton/day
‣ 1st market opportunities– WtE/MRF facilities, medical waste plastics– Chemical plants
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Batch Process: Hydrocracking of HDPE
‣ HDPE conversion accomplished within ~3 h
‣ Selectivity changes with time
‣ >80% liquid hydrocarbons
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Batch Process: Hydrocracking of HDPE – flow rate
‣ Higher flow rate leads to more small hydrocarbons
‣ Slower flow decrease the hydrocracking reaction rate
Batch Process: Hydrocracking of HDPE – different products
‣ Alternative catalysts
‣ ~90% conversion
‣ ~80% C3-C5 aliphatic hydrocarbons
Batch Process: Hydrocracking of Different Plastics
‣ Hydrocracking of HDPE, LDPE, PP and PS are compared under consistent reaction conditions
‣ Kinetics are rather consistent for aliphatic polymers
‣ Sluggish reaction for PS due to molecular hindrance
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Batch Process: Hydrocracking of Different Plastics
▸Branching reduces BTX yields
▸PS produces the most BTX but the isomer for xylene is different
Batch Process: Hydrocracking of Mixed Plastics
‣ Equal-mass mixture of HDPE, LDPE, PP and PS
‣ BTX yields seems to be averaged out, albeit lower xylene yields
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Batch Process: Hydrocracking of PVC
‣ Incineration of PVC produces toxic chlorinated hydrocarbons and dioxins
‣ Dechlorination pretreatment is developed to remove chlorine with minimized coking
‣ Hydrocracking the hydrocarbon residues produces BTX
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T2M
‣ Market analysis– Sourcing of end-of-life plastics– BTX production and consumption
‣ Pre-engineering design for 1 ton/day – PFD– Capital cost est.– To be delivered by May, 2022
Current Industrial Production of BTX from Refinery
12January 14, 2022 https://www.jonellsystems.com/industries/refinery-petrochemical/btx-filtration/
BTX Market Overview
The gl obal mar ket f or benzene, xyl ene and t ol uene seems t o be hi ghl y f r agment ed wi t h t he U. S. i n t he dr i vi ng seat . As i a- Paci f i c i s pr oj ect ed t o be t he f as t es t gr owi ng gl obal expor t er wi t h Sout h Kor ea l eadi ng t he pack. Some of t he key pl ayer s i ncl ude:
● BP● Chevr on● Exxon Mobi l● Chi na Nat i onal Pet r ol eum Cor p. ( CNPC)● For mosa Pl as t i cs Gr oup ( FPG)● ConocoPhi l l i ps● JX Hol di ngs● Fl i nt Hi l l s Resour ces● t he I neos Gr oup● Saudi Bas i c I ndus t r i es Cor p. ( SABI C)● DOW Chemi cal s● Royal Dut ch Shel l● SI NOPEC● LG Chem. Lt d.● Lot t e Chemi cal
sour ce: ht t ps : / / www. t r anspar encymar ket r esear ch. com/ benzene- xyl ene-t ol uene. ht ml
Summary Slide
‣ Efficient upcycling of hydrocarbon plastics into BTX via hydrocracking has been demonstrated with batch reactor
‣ Focus of the next phase– Continuous operation of hydrocracking– Refine TEA model with continuous operation– Pre-engineering design of pilot plant
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