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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