Pneumatic Vapor Valve to Shorten Coking Cycle
Coke drum overhead vapor valves are massive affairs. Switching a pair of 20-ft diameter drums may require the manipulation of four 18-in. and four 12-in. valves. Size aside, the vapor valves are difficult to open and close because of coke deposits on valve internal parts. Removing the insulation on piping upstream of the vapor valves or injecting a small liquid quench (typically 3 vol%) into the vapor line at the first 90° turn will help.
To minimize the amount of hard physical labor required to switch drums every 12 hours, the vapor valves should be fitted with locally controlled air operators. Such a device is little more than an air gun permanently mounted to the stem of each valve. The speed of the valve movement is controlled with a Win. air valve.
Categories: Process Troubleshooting | Tags: vapor valves | Leave a comment