Decoking process

• US 4,673,442 A
• Filed: 02/21/1986
• Issued: 06/16/1987
• Est. Priority Date: 01/29/1985
• Status: Expired due to Fees

• Current Assignee: Standard Oil Company (BP PLC)
• Original Assignee: Standard Oil Company (BP PLC)
• Inventors: Kaplan, Richard D.
• Primary Examiner(s): Coe, Philip R.
• Application Number:
  US06/832,157
• Time in Patent Office: 480 Days
• Field of Search: 134/24, 134/39, 134/95, 134/98, 134/99, 134/167 R, 134/167 C, 134/168 R, 134/168 C, 134/171, 134/172, 134/178, 201/2, 202/241, 208/48 R, 196/122, 239/DIG. 13, 239/178, 239/186, 239/227, 239/248, 239/447, 239/562, 239/563
• US Class Current: 134/24
• CPC Class Codes: C10B 33/006 Decoking tools, e.g. hydraulic coke removing tools with boring or cutting nozzles

Abstract

A specially constructed decoking apparatus is provided to effectively and efficiently bore a pilot hole and ream the remainder of a bed of coke with a high pressure stream of water or other cutting fluid without first changing nozzle heads or using different cutting instruments. The novel decoking apparatus has a vertical pilot nozzle and pilot pipe and a separate reamer and reaming pipe which are secured adjacent to each other and work in tandem.

Claims

1. A decoking process, comprising the steps of:

(a) lowering a pilot nozzle and reamer of a decoking instrument into a coking vessel;

(b) cutting a vertical pilot hole through a bed of coke in said coking vessel with said pilot nozzle of said decoking instrument by injecting a fluid through said pilot nozzle into said bed of coke at a pressure ranging from about 500 psi to about 3500 psi and moving said pilot nozzle and reamer substantially vertically through said bed of coke;

(c) reaming substantially all of the remaining bed of coke with said decoking instrument after step (b) while maintaining said pilot nozzle and reamer in fixed relationship to each other without removing said pilot nozzle and reamer of said decoking instrument from said coking vessel or adjusting the span and distance between said pilot nozzle and reamer, said reaming including substantially stopping the flow of fluid to said pilot nozzle, injecting said fluid through said reamer into said remaining bed of coke at a pressure ranging from about 500 psi to about 3000 psi and, thereafter, moving said reamer and pilot nozzle substantially vertically through said bed of coke while concurrent rotating said reamer to radially cut and substantially remove said remaining bed of coke; and

(d) stopping the flow of fluid to said reamer and withdrawing said pilot nozzle and reamer of said decoking instrument from said decoking vessel.

2. A decoking process in accordance with claim 1 wherein said cutting and reaming comprises water injection.

3. A decoking process in accordance with claim 1 wherein said pilot nozzle and reamer of said decoking instrument are moved simultaneously downwardly through said bed of coke during said cutting, said pilot nozzle and reamer of said cutting instrument are then raised above said bed of coke, and then said pilot nozzle and reamer of said decoking instrument are moved simultaneously downwardly through said bed of coke during said reaming.

4. A decoking process in accordance with claim 1 wherein said pilot nozzle and reamer decoking instrument are moved concurrently downwardly through said bed of coke during said cutting and said pilot nozzle and reamer decoking instrument are moved concurrently upwardly through said bed of coke during said reaming to minimize plugging of said pilot hole.