Process for conversion of waste plastics into hydrocarbons

Patent metadata

Field	Value
Publication number	US-2024279553-A1
Application number	US-202218571990-A
Country	US
Kind code	A1
Filing date	Jun 17, 2022
Priority date	Jun 22, 2021
Publication date	Aug 22, 2024
Grant date	—

Abstract

A process for production of chemical feedstocks from waste plastics, the process comprising providing a process configuration comprising a fractionation tower ( 1 ), a furnace ( 2 ), one or more coke drum(s) ( 3 ), and a pre-reactor ( 4 ), configured so that a bottoms stream (A) from the fractionation tower is mixed with an oligomeric stream (L) and supplied to the furnace, the product stream from the furnace (C) is supplied to a coke drum, and an overhead stream (D) from the coke drum is supplied back to the fractionation tower; wherein the oligomeric stream (L) is obtained as product stream from conversion of a waste plastics stream (B) in the pre-reactor, and has a weight average molecular weight of between 5,000 and 10,000 g/mol. Such process allows for the conversion of a wide variety of waste plastics into valuable chemical products.

First claim

1 . A process for production of chemical feedstocks from waste plastics, the process comprising providing a process configuration comprising a fractionation tower ( 1 ), a furnace ( 2 ), one or more coke drum(s) ( 3 ), and a pre-reactor ( 4 ), configured so that a bottoms stream (A) from the fractionation tower is mixed with a stream originating from waste plastics (L), and supplied to the furnace, the product stream from the furnace (C) is supplied to a coke drum, and an overhead stream (D) from the coke drum is supplied back to the fractionation tower;
wherein the stream (L) is obtained as product stream from conversion of a waste plastics stream (B) in the pre-reactor; wherein the stream (L) is supplied in molten condition.

2 . The process according to claim 1 , wherein in the fractionation tower a fractionation of a mixture comprising the overhead stream (D) and a residual oil (K) is performed to result in a gaseous output stream (F) obtained as overhead stream from the fractionation tower, a naphtha-range stream (G), a light gas oil stream (J), a heavy gas oil stream (H), and a bottoms stream (A).

3 . The process according to claim 1 , wherein the stream (L) is supplied at a temperature of ≥300 and ≤450° C.

4 . The process according to claim 1 , wherein the bottoms stream (A) is supplied at a temperature of ≥300 and ≤400° C.

5 . The process according to claim 1 , wherein the combined feed (A) and (B) are heated in the furnace by passing the feed through heating tubes and subjecting it to external heat energy to obtain a furnace product stream (C) having a temperature of >450° C. and ≤550° C.

6 . The process according to claim 1 , wherein the bottoms stream (A) has a boiling point of ≥400° C.

7 . The process according to claim 1 , wherein the pre-reactor ( 4 ) is a melt extruder.

8 . The process according to claim 1 , wherein the pre-reactor ( 4 ) is operated at a temperature of ≥350 and ≤450° C., and/or wherein the waste plastic is subjected to a residence time in the pre-reactor of ≥10 min.

9 . The process according to claim 2 , wherein the residual oil (K) is a residual oil obtained from atmospheric distillation of crude oil, or a residual oil obtained from vacuum distillation of the residual oil obtained from atmospheric distillation of crude oil.

10 . The process according to claim 1 , wherein the coke drum is operated at a pressure of between 100 and 600 kPa.

11 . The process according to claim 1 , wherein the fractionation tower operated so that the temperature in the bottom section of the tower is between 340° C. and 385° C.

12 . The process according to claim 1 , wherein the furnace product stream (C) comprises ≥0.1 and ≤50.0 wt % of the stream (L), with regard to the total weight of the stream (C).

13 . The process according to claim 1 , wherein a gaseous stream (M) comprising HCl that is formed from decomposition of chlorine-containing polymers, is removed from the pre-reactor ( 4 ), wherein the pre-reactor ( 4 ) is operated at a temperature where decomposition of the chlorine-containing polymers that are present in the waste plastics stream (B) occurs.

14 . The process according to claim 1 , wherein the pre-reactor ( 4 ) comprises a first pre-reactor ( 4 A) and a second pre-reactor ( 4 B), wherein in the first pre-reactor ( 4 A), which may for example be a melt extruder such as a twin-screw melt extruder, the solid mixed waste plastics stream (B), which may for example comprise 80-90 wt % of polyolefins, and 1-5 wt % of chlorine-containing polymers such as polyvinylchloride (PVC), is heated to such temperature, where the chlorine-containing polymers are molten and decompose to form a gaseous HCl product that is removed as stream (M), so that a molten, dechlorinated plastic stream (B′) is formed, which then is supplied to a second pre-reactor ( 4 B), which may for example be a melt extruder such as a twin-screw melt extruder, wherein stream (B′) is processed at a temperature of ≥350 and ≤450° C., during a residence time of >10 min to form the oligomeric stream (L).

15 . The process according to claim 13 , wherein the stream (M) is further contacted with an aqueous stream (R) containing a base to neutralise the HCl and thereby produce an aqueous stream (S).

Assignees

• Sabic Global Technologies Bv

Inventors

• Schucker Robert C
• Loiland Jason
• Farmer Dustin
• Narayanaswamy Ravichander
• Stanislaus Alexander
• Isimjan Tayirjan Taylor

Classifications

• C10G2300/4012

  Pressure · CPC title

• C10G2300/4006

  Temperature · CPC title

• C10G2300/202

  Heteroatoms content, i.e. S, N, O, P · CPC title

• C10G2300/107

  Atmospheric residues having a boiling point of at least about 538 °C · CPC title

• C10G2300/1033

  Oil well production fluids · CPC title