Making large horizontal drums safe for entry has been a significant problem for oil refineries and processing facilities. There is simply too much horizontal surface area and too few drains to fully clear and clean. The problem is exacerbated when there is a significant amount of sludge in the drum. Not only is the sludge difficult to remove, but it tends to off gas when disturbed, endangering workers that are assigned to manually remove it following traditional clearing methods.
A large Gulf States refinery had a 12’x30’ flare knock out drum that required maintenance. Scans of the drum showed that it contained several feet of sludge. The refinery was planning to clean the drum using a series of liquid flushes and manual mopping over the course of five days. A better approach would allow the refinery to put the flare back into service faster and provide a safer work environment for their employees.
Refined Technologies has cleaned hundreds of horizontal vessels since 2001. Over that time, we have continuously improved our patented Vaporganic® process using our high-solvency QuikTurn® chemistry, while adapting it to specific applications in the refinery. In this case, we believed that we could reduce the clearing and cleaning time from 5 days to just 24 hours by adapting our process to this flare knock out drum.
The process began with two “rumble” steps. These involved adding QuikTurn chemistry to an amount of water in the drum. Steam was injected into the bottom of the drum to agitate the sludge. Adding QuikTurn to the water helped dissolve the sludge and make it miscible in the water.
The rumble steps were followed by a “polish” step using QuikTurn and the Vaporganic process. The bulk of the sludge was removed during rumbling but the polish step effectively removed residual sludge and completely cleared the drum of H2S and LEL. Since the refinery was also concerned about pyrophorics, we followed the polish step with a Permanna rinse.
The cleaning project was in fact completed in less than 24 hours. Adding two additional low point drains (to make a total of four) and applying a 2” steam line to each contributed to the success of this project. Refinery personnel were very impressed with the results which can be seen in a picture taken of the drum upon entry.