COKE CUTTING
SYSTEMS
The hydraulic decoking process is a complex manufacturing process that requires the use
of high-quality equipment and intelligent control systems.
The process of coke removal from coke drums is performed by hydraulic decoking and
is divided into two stages. During the first stage, a hole (stem) is made in the coke layer.
In the second stage, the coke is cut into layers as the tool is lowered by the operator. Hydraulic cutting tools should be mounted on the end of a hollow drilling stem that is suspended from a swivel joint. The drilling stem rotates by means of an electric motor.
A platform-based hoist is designed to raise and lower the drilling stem within the structure of the derrick built above the coke drums. The decoking water is supplied by a high-pressure coke cutting jet pump. To avoid frequent pump startups and shutdowns, a special hydraulic bypass control valve is used. After coke removal, the cover is reinstalled on the non-working coke drum, then steam blowing and pressing need to be carried out to extract air. After that, the fractionation column is fed with steam from the working coke drum, which is currently being filled. The vapor-liquid mixture formed as a result of steam condensation in a non-working fractionation column enters the purge column. After the coke drum has been sufficiently warmed up, it is ready to be filled.
1. Hoist — a lifting device with either electric
or hydraulic drive;
2. HPU — Hydraulic Power Unit (not shown);
3. HPW — High Pressure Water line, flexible hose or swing pipe;
4. LCP — Local (Operator) Control Panel free standing or installed in operator shelter (optional) one panel for one pair of drums. CH + FFA – Crosshead with Free Fall Arrestor;
5. DSD — Drill Stem Drive, hydraulically or electrically driven;
6. PB — Single and double Pulley Block equipped with instruments for rope load and tool position;
7. Guide Rails — T-type guide rails with shims, connectors, bolts and nuts with latching mechanism and proximitor switches;
8. DS+Tool-Drill — Drill Stem (threaded or welded), Tool (manual or autoswitch tool);
9. TOP-Unheading Device — Automated Top Unheading (optional) Device, electrically or hydraulically driven;
10. Feed Entry — (optional) side entry connection of feedline, separate or connected to cone;
11. Bottom Unheading Device — (optional) automatic bottom unheading system hydraulically driven, with hanger and installation system
12. LCP — Local (Operator) Control Panel for bottom unheading system, installed in an operator shelter (optional), for close and remote operation — (not shown);
SYSTEM
COMPONENTS
COKE CUTTING TOOL
The tool combines a drilling and cutting modes.
Basic Design:
• Slim tool, diameter 13” (310 mm);
• Low lift force;
• Low torque;
• Hydrodynamic optimized channels;
• Switching device;
• Manual / automatic switch;
FREE FALL ARRESTOR
Features:
• Simple functional testing performed
on a routine basis;
• Separate Arrestor cables, cable guides
for spring cans are eliminated;
• Cable grippers are eliminated;
• TÜV (UL/FM equivalent) approved, proven
in over 5000 installations;
DRILL STEM DRIVE
The drill stem drive (DSD) can be installed without interruption to existing decoking operation. DSD
is adapted to existing crossheads (+/-3”) and can
be adapted to existing crossheads without modification to the control limit switches or mechanical stops. In addition, if time permits, DSD can be adapted to the drill stem from a unibolt coupling to a flange connection.
JET WATER PUMPS /
Jet Water Pumps designed to handle hydraulic decoking:
The ADC Model designed according to
API 610 (BB5 type pump).
The pumps are designed according to API 610 standard (BB5 type pump).
• Capacity up to 400 m³/h;
• Head max. 4,000 m;
• Rotation speed according to conditions of usage;
• Temperature standard up to 150°C;
• Higher heads levels on a Customer’s demand;
• High-pressure water jet creation for water
jet cutting;