Method for making a heavy wax composition

• US 6,143,940 A
• Filed: 12/30/1998
• Issued: 11/07/2000
• Est. Priority Date: 12/30/1998
• Status: Expired due to Term

• Current Assignee: University Of Kentucky Research Foundation (University of Kentucky)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.), University Of Kentucky Research Foundation (University of Kentucky)
• Inventors: Miller, Stephen J., Huffman, Gerald P., Shah, Naresh
• Primary Examiner(s): Knode, Marian C.
• Assistant Examiner(s): Nguyen, Tam M.
• Application Number:
  US09/223,227
• Time in Patent Office: 678 Days
• Field of Search: 208/69, 208/97, 585/240, 585/241
• US Class Current: 585/240
• CPC Class Codes: C10G 1/10 from rubber or rubber waste
• CPC Class Codes: C10G 69/06 including at least one step of thermal cracking in the absence of hydrogen

Abstract

The invention includes a process of making a wax composition including: a process for making a heavy wax composition including the steps of (1) contacting a waste plastics feed containing primarily polyethylene in a pyrolysis zone at sub-atmospheric pressure, whereby at least a portion of the waste plastics feed is cracked, thereby forming a pyrolysis zone effluent including 1-olefins and n-paraffins; and (2) passing the pyrolysis zone effluent to a hydrotreating zone, for contacting with a hydrotreating catalyst at catalytic conditions.

Claims

1. A process for making a heavy wax composition comprising the steps of:

(a) passing a waste plastics feed comprising polyethylene to a pyrolysis zone, having a sub-atmospheric pressure, whereby at least a portion of said waste plastics feed is cracked, thereby forming a pyrolysis zone effluent comprising 1-olefins and n-paraffins;

(b) passing at least a portion of said pyrolysis zone effluent to a catalytic hydrotreating zone wherein at least a portion of said pyrolysis zone effluent is contacted with a hydrotreating catalyst at hydrotreating conditions, thereby producing a hydrotreated pyrolysis zone effluent; and

(c) wherein said hydrotreated pyrolysis zone effluent comprises a wax having a melting point of at least about 100°

C.

2. The process of claim 1, wherein at least about 10 wt. % of said hydrotreated pyrolysis zone effluent comprises a wax having a boiling point of at least about 1000°

F.

3. The process of claim 1, wherein a major portion of said wax boils in the bright stock range.

4. The process of claim 1, wherein said pyrolysis zone is at sub-atmospheric pressure not greater than about 0.75 atmospheres.

5. The process of claim 1, wherein said pyrolysis zone is at sub-atmospheric pressure not greater than about 0.50 atmospheres.

6. The process of claim 1, further comprising:

(a) passing said pyrolysis zone effluent of step (a), to a separation zone, thereby separating said pyrolysis zone effluent into at least one heavy fraction and one middle fraction, said middle fraction comprising 1-olefins; and

(b) passing at least a portion of said pyrolysis effluent heavy fraction to said catalytic hydrotreating zone.

7. The process of claim 1, wherein pyrolysis zone includes an inert gas selected from the group consisting of nitrogen, hydrogen, steam, methane or a recycled light fraction from said separations zone in step (b).

8. The process of claim 1, wherein said waste plastics feed comprises at least about 95 wt. % polyethylene.

9. The process of claim 1, wherein from about 25 wt. % to about 75 wt. % of said pyrolysis zone effluent comprises 1-olefins.

10. The process of claim 1, wherein said waste plastics feed comprises non-plastic material comprising paper or metal.

11. The process of claim 6, wherein the yield of said wax based on the weight of said pyrolysis effluent heavy fraction is at least about 50 wt. %.

12. The process of claim 6, wherein the yield of said wax based on the weight of said pyrolysis effluent heavy fraction is at least about 60 wt. %.

13. The process of claim 6, wherein the yield of said wax based on the weight of said pyrolysis effluent heavy fraction is at least about 70 wt. %.

14. The process of claim 1, wherein said pyrolysis zone is a temperature of from about 500°

C. to about 700°

C.

15. The process of claim 1, wherein said pyrolysis zone is a temperature of from about 600°

C. to about 700°

C.

16. The process of claim 1, wherein prior to passing said waste plastic feed to said pyrolysis zone, said waste plastic feed is ground and substantially liquefied.

17. The process of claim 1, wherein the S and N levels of said hydrotreated pyrolysis zone effluent are not greater than about 5 ppm S and 1 ppm N.

18. A process for making a heavy wax composition comprising the steps of:

(a) passing a waste plastics feed comprising polyethylene to a pyrolysis zone having a temperature of from about 600°

C. to about 700°

C. and pressure not greater than about 0.75 atm., whereby at least a portion of said waste plastics feed is cracked, thereby forming a pyrolysis zone effluent comprising 1-olefins and n-paraffins;

(b) passing said pyrolysis zone effluent, to a separation zone, thereby separating said pyrolysis zone effluent into at least a one heavy fraction and one middle fraction, said middle fraction comprising normal alpha olefins, to a separation zone;

wherein said pyrolysis effluent heavy fraction portion is separated from said pyrolysis effluent middle fraction;

(c) passing pt least a portion of said pyrolysis effluent heavy fraction to a catalytic hydrotreating zone wherein at least a portion of said pyrolysis effluent heavy fraction is contacted with a hydrotreating catalyst at hydrotreating conditions, thereby producing a hydrotreated pyrolysis effluent heavy fraction; and

(d) wherein said hydrotreated pyrolysis effluent heavy fraction comprises a wax having a melting point of at least about 100°

C.

19. The process of claim 18, wherein at least about 10 wt. % of said hydrotreated pyrolysis effluent heavy fraction comprises a wax having a boiling point of at least about 1000°

F.