Method of converting plastic waste into useful stock

Patent metadata

Field	Value
Publication number	US-10894870-B2
Application number	US-201916389855-A
Country	US
Kind code	B2
Filing date	Apr 19, 2019
Priority date	Apr 19, 2018
Publication date	Jan 19, 2021
Grant date	Jan 19, 2021

Abstract

Methods of recovery of pristine polymers and hydrocarbon mixtures from a sorted waste feedstock or mixtures of waste feedstock, which are with or without organic additives are disclosed. The methods include Sequential Selective Extraction and Adsorption (SSEA), Hydrothermal Processing (HTP), and a combination of SSEA and HTP. Exemplarily, SSEA includes selecting a first solvent (S1), inputting the S1 and a sorted feedstock free of organic additives into an extractor, heating, waiting, and separating insolubles forming a pristine polymer solution. Exemplarily, HTP includes inputting a hydrothermal solvent and a sorted feedstock free of organic additives into a reactor, heating to form subcritical or supercritical H2O, waiting, causing thermal depolymerization to produce a slurry, cooling, venting formed gases and separating the hydrocarbon mixture.

First claim

The invention claimed is:

1. A method of recovery of pristine polymers frog a sorted waste feedstock free of organic additive, comprising:
a. selecting a first solvent (S1), wherein the S1 is within a Hansen's sphere with respect to the sorted waste feedstock and wherein the S1 is in a predetermined list of solvents;
b. inputting the S1 into an extractor;
c. inputting the feedstock into the extractor, thereby generating a mixture (M);
d. heating the M to a temperature ranging from 5° C. to 180° C.;
e. waiting a predetermined amount of time, thereby forming a polymer solution (PSl);
f. separating insolubles from the PSl, forming a pristine polymer solution (PSS);
g. separating the pristine polymer (PrP) from the PPS; and
h. collecting the separated PrP.

2. The method of claim 1 , wherein the step of separating the PrP from the PPS is by evaporating the S1.

3. The method of claim 1 , further comprising:
recycling the S1.

4. The method of claim 1 , wherein the step of separating the PrP from the PPS is by adding a second solvent (S2), wherein Hansen parameters of the mixture of the S1 and S2 are outside the Hansen's sphere for the PrP.

5. A method of recovery of pristine polymers from a sorted waste feedstock containing organic additives, comprising:
a. selecting a first solvent (S1), wherein the S1 is within a Hansen's sphere with respect to the sorted waste feedstock and wherein the S1 is in a predetermined list of solvents;
b. inputting the S1 into an extractor;
c. inputting e feedstock into the extractor, thereby generating a mixture (M);
d. heating the M to a temperature ranging from 5° C. to 180° C.;
e. waiting a predetermined amount of time, thereby forming a polymer solution containing the organic additives (PSlO);
f. separating insolubles from the PSlO, forming a pristine polymer solution with organic additives (PPSlO);
g. adsorbing the PPSlO using one or more adsorbents for the organic additives to thereby remove organic additives forming a pristine polymer solution (PPS);
h. separating the pristine polymer (PrP) from the PPS; and
i. collecting the separated PrP.

6. The method of claim 5 , wherein the adsorption step is by a stirred tank, and the step further includes separating the one or more adsorbents from output of the stirred tank prior to forming the PPS.

7. The method of claim 5 , wherein the adsorption step is by a single bed.

8. The method of claim 5 , wherein the adsorption step is by a carrousel.

9. The method of claim 5 , wherein the adsorption step is by a simulated moving bed (SMB).

10. The method of claim 4 , wherein the step of separating the PrP from the PPS is by evaporating the S1.

11. The method of claim 10 , further comprising:
recycling the S1.

12. The method of claim 4 , wherein the step of separating the PrP from the PPS is by adding a second solvent (S2), wherein Hansen parameters of the mixture of the S1 and S2 are outside the Hansen's sphere for the PrP.

13. A method of recovery of pristine polymers from a mixture of a plurality of waste feedstock of different types of plastics (mixture of plastics) each free of organic additives, comprising:
a. inputting the mixture of plastics into an extractor;
b. selecting a solvent mixture (SMi) from a plurality of solvents, Hansen parameters of the selected solvent mixture are within the Hansen's sphere of a target plastic of the mixture of plastics and where each solvent of the plurality is in a predetermined list of solvents;
c. inputting the selected SMi into the extractor, thereby generating a mixture (M i );
d. selectively heating the M i to a temperature ranging 5° C. to 180° C. corresponding to a schedule of temperature vs. known type of plastic;
e. waiting a predetermined amount of time, thereby forming a polymer solution (PSl i ) containing a mixture of solvents and polymers;
f. separating insolubles from the PSl i , forming a pristine polymer solution (PPS i ), wherein the insolubles are provided to the extractor during a next cycle (i+1);
g. separating the pristine polymer (PrPi) frog the PPSi;
h. collecting the separated PrPi; and
i. repeating steps b through h for each type of target plastic where the index i corresponds to the number of plastic types in the mixture of plastics, where i=1, . . . M and K corresponds to the number of target plastics, where K≤M.

14. The method of claim 13 , wherein the step of separating the PrPi from the PPSi is by evaporating the SMi.

15. The method of claim 14 , further comprising:
recycling the SMi.

16. The method of claim 13 , wherein the step of separating the PrPi from the PPSi is by adding a separation solvent (SSi), wherein Hansen parameters of the mixture of the SMi and SSi are outside the Hansen's sphere for the PrPi.

17. A method of recovery of pristine polymers from a mixture of a plurality of waste feedstock of different types of plastics (mixture of plastics) each containing organic additives, comprising:
a. inputting the mixture of the plurality of waste feedstock into an extractor;
b. selecting a solvent mixture (SMi) from a plurality of solvents, where each solvent of the plurality is in a predetermined list of solvents, Hansen parameters of the selected solvent mixture are within the Hansen's sphere of a target plastic of the mixture of plastics; and
c. inputting the selected SMi into the extractor, thereby generating a mixture (M i );
d. selectively heating the M i to a temperature ranging from 5° C. to 180° C. corresponding to a schedule of temperatures vs. known type of plastic;
e. waiting a predetermined amount of time, thereby forming a polymer solution containing the organic additives (PSlOi);
f. separating insolubles from the PSlOi, forming a pristine polymer solution with organic additives (PPSlOi);
g. adsorbing the PPSlOi using one or more adsorbents for the organic additives to thereby remove organic additives forming a pristine polymer solution (PPSi);
h. separating the pristine polymer (PrPi) from the PPSi; and
i. collecting the separated PrPi; and
j. repeating steps b through i for each type of target plastic where the index i corresponds to the number of plastic types in the mixture of plastics, where i=1, . . . M and K corresponds to the number of target plastics, where K≤M.

18. The method of claim 17 , wherein the adsorption step is by a stirred tank, and the step further includes separating the one or more adsorbents from output of the stirred tank prior to forming the PPSi.

19. The method of claim 17 , wherein the adsorption step is by a single bed (SBi).

20. The method of claim 17 , wherein the adsorption step is by a carrousel (CARi).

21. The method of claim 17 , wherein the adsorption step is by a simulated moving bed (SMBi).

22. The method of claim 17 , wherein the step of separating the PrPi from the PPSi is by evaporating the SMi.

23. The method of claim 22 , further comprising:
recycling the SMi.

24. The method of claim 17 , wherein the step of separating the PrPi from the PPSi is by adding a separation solvent (SSi), wherein Hansen parameters of the mixture of the SMi and SSi are outside the Hansen's sphere for the PrPi.

25. A method of recovery of hydrocarbon mixtures from a sorted waste feedstock free of organic additives, comprising:
a. inputting a predetermined volume of a hydrothermal solvent into a reactor, the hydrothermal solvent comprising H 2 O;
b. inputting the feedstock into the r

Assignees

• Purdue Research Foundation

Inventors

• Chen Wan-Ting
• Wang Nien-Hwa L
• Jin Kai

Classifications

• C10G2400/04

  Diesel oil · CPC title

• C10G2400/02

  Gasoline · CPC title

• C10G2300/1003

  Waste materials · CPC title

• B01D17/0208

  by sedimentation · CPC title

• C10G1/10

  from rubber or rubber waste · CPC title