Delayed coke drum quench systems and methods having reduced atmospheric emissions

• US 10,479,941 B2
• Filed: 10/17/2018
• Issued: 11/19/2019
• Est. Priority Date: 09/21/2015
• Status: Active Grant

• Current Assignee: Bechtel Energy Technologies & Solutions Incorporated
• Original Assignee: Bechtel Hydrocarbon Technology Solutions, Inc. (Bechtel Group Incorporated)
• Inventors: Ward, John D., Heniford, Richard, Alexander, Scott
• Primary Examiner(s): Miller, Jonathan
• Assistant Examiner(s): Pilcher, Jonathan Luke
• Application Number:
  US16/163,266
• Publication Number:
  US 20190048265A1
• Time in Patent Office: 398 Days
• CPC Class Codes: C10B 39/04 Wet quenching
• CPC Class Codes: C10B 55/00 Coking mineral oils, bitumen, tar, and the like or mixtures thereof with solid carbonaceous material cracking oils C10G
• CPC Class Codes: C10G 9/005 Coking (in order to produce liquid products mainly)

Abstract

Systems and methods for reducing atmospheric emission of hydrocarbon vapors by flashing off hydrocarbon vapors in an overflow drum where the pressure is ultimately reduced to 0 psig and then flashing off any remaining hydrocarbon vapors in an overflow tank wherein the pressure in the overflow tank is reduced to 0 psig by an overflow ejector.

Claims

1. A system for reducing atmospheric emissions of hydrocarbon vapors in a delayed coke drum quench overflow system, which comprises:

an overflow drum connected to a blowdown header line for reducing hydrocarbon vapors and producing a vapor overflow remainder and a liquid overflow remainder;

an overflow tank, connected to the overflow drum by a liquid overflow remainder line, for separating at least one of skim oil, water, coke fines, and tank vapor from the liquid overflow remainder; and

a tank vapor line in fluid communication with the overflow tank for transmitting the tank vapor to an overflow ejector, wherein the overflow ejector includes an inlet in fluid communication with the tank vapor line and an outlet in fluid communication with a steam line for reducing the pressure in the overflow tank to 0 psig.

2. The system of claim 1, further comprising a suction pressure controller, the suction pressure controller in communication with the inlet of the overflow ejector and the outlet of the overflow ejector, for preventing a vacuum in the tank vapor line.

3. The system of claim 2, further comprising:

a liquid overflow remainder valve in the liquid overflow remainder line and a limit controller associated with the overflow drum and adapted to control the liquid overflow remainder valve for maintaining a constant level in the overflow drum.

4. The system of claim 3, further comprising:

a non-air gas supply in communication with the overflow tank; and

a non-air gas valve intermediate the non-air gas supply and the overflow tank for preventing a vacuum in the overflow tank.

5. The system of claim 4, further comprising:

a check valve, the check valve in the steam line intermediate an overhead line, the overhead line intermediate a quench tower and a blowdown condenser, and an overflow drum vapor line, to prevent flow from the quench tower to the overflow tank or the overflow drum.

6. The system of claim 5, further comprising:

a steam supply in connection with the overflow tank; and

an overflow ejector valve intermediate the steam supply and the overflow ejector to open a flow of steam to the overflow ejector.

7. The system of claim 1, further comprising:

an overflow line in communication with the overflow tank and a quench water tank for communicating water from the overflow tank to the quench water tank.

8. The system of claim 7, further comprising:

an overflow line valve in the overflow line for limiting a flow of water through the overflow water line.

9. The system of claim 8, further comprising:

a coke cutting line connected to the quench water tank;

a quench water line connected to the quench water tank;

a water in-flow line from the quench water line to the overflow tank; and

a water inflow valve in the water in-flow line, intermediate the quench water line and the overflow tank, for adjusting a volume of water in the overflow tank.

10. The system of claim 1, further comprising:

a coke cutting line connected to the overflow tank; and

a quench water line connected to the overflow tank.

11. A method for reducing atmospheric emissions of hydrocarbon vapors in a delayed coke drum quench overflow system, which comprises:

producing a vapor overflow remainder and a liquid overflow remainder from an overflow drum;

separating tank vapor from the liquid overflow remainder in an overflow tank;

transmitting the tank vapor to the steam line through an overflow ejector; and

reducing the pressure of the overflow tank to 0 psig.

12. The method of claim 11, further comprising:

introducing water into the overflow drum to maintain a constant level of water in the overflow drum.

13. The method of claim 12, further comprising:

introducing a non-air gas into the overflow tank to prevent a vacuum in the overflow tank.

14. The method of claim 13, further comprising:

positioning a check valve in a steam line to prevent flow from a quench tower to the overflow tank or the overflow drum.