7 replies to this topic

[Pilesar]

What is the most expedient way to verify distillation tower internal manways are properly fastened after column tray work? I think it is typical that the last man inside closes all the doors on his way out. But this method does not allow independent verification and the financial consequences of a failed restart can be substantial. Do you have experience with a practical method to reduce the risk of insecure internal manways?

[Bobby Strain]

You could install them yourself. Otherwise, you need to assure that the workers are properly trained and supervised.

 

Bobby

[Art Montemayor]

I always used a trusted and well-trained "stake holder" in the operations within the maintenance department.  I limited the quantity of trays a man could "button-up" during a reasonable stay within the column.  This turned out to be 5 trays per man, using a team of two key men to do the buttoning-up.  This allowed me to give each man a rest period after a reasonable time within the column and reduced, in my opinion, anything going bad with using only one individual.  They were trained and worked as a team.  I have always considered vessel entry and maintenance inside confined spaces to be critical and potentially hazardous, so I limited the amount of time a person was inside and could be relied to be effective and do a proper job - without taking risks.

 

The "stake" that these key individuals had was a financial reward in the form of a bonus after successfully starting up and operating the distillation column.  These type of jobs are, as you infer, very critical to any operating plant and could result in extremely costly failures if the critical jobs are not done precisely correct.  That's why I prepared and trained the selected individuals on a very personal basis and insisted they be given a senior specialist status in our maintenance department.  Confined space work inside a column takes skill, process knowledge, and dedication in doing a proper, first-class job under trying and difficult conditions.  Additionally, as we all know, there are latent hazards that can occur if the procedure and safety precautions are not strictly followed.  I have a deep respect for persons who do this since I worked my way through college in a shipyard as a boilermaker, pulling and installing tubes in ships' boilers and working in the double bottoms of tanker vessels.  I can relate to the sweaty, hot, taxing conditions inside a vessel and the cramped and scraped knees, fingers, and other body parts that have to accommodate the confined space given while doing a job that could result in failure for the project if not done right.

 

As Bobby correctly points out, the only other option is for you to do the job.  I was lucky and fortunate in having good, dedicated workers who were interested in doing a good job and in being recognized as having contributed to a success story.

[latexman]

A word of warning from the school of experience.  Doing it yourself is NOT easy for one who does not do it routinely.  As a much younger, fit, and trim engineer, I found confined space entry in process equipment required a deliberate well planned pace with breaks for hydration and rest in relation to the climate inside and outside the equipment.  I recommend a cooler of assorted Gatorades at the job site for yourself, AND just in case someone forgets theirs!  THAT probably kept me from passing out several times in the hot humid climate of Freeport, TX.

[breizh]

Hi ,

That's a tricky one . Definitely need someone in your organization to witness the quality of the work , and already said skilled people are keys .

my 2 cents.

Breizh

[Pilesar]

Thank you for the comments. For large turnarounds with a lot of activity, the regular maintenance department is overwhelmed. When replacing column internals, we bring in one of the service companies which specialize in distillation column labor since the job should be well-defined and their workers are overseen by experienced foremen. Sometimes we have simultaneous work inside several columns around the clock and need to rely on the column specialists to do their job correctly. We can inspect the completed job up until the final buttoning which is difficult to verify. In narrow columns, there may be room for only one person on a tray. We should consider whether to transfer the final buttoning job to an in-house "stake holder" but much of our routine plant maintenance is performed by a contract company also! I would still be uncomfortable with the lack of verification even if I were to do the job myself... any person can make a mistake and it is easy to get disoriented inside a distillation column. I will think more on this.

[Bobby Strain]

Just make certain your contractor has good supervision. I don't think you have need for concern. If you really want verification, consider a photograph of each completed tray. I never encountered problems related to reassembly. It's the original trays that might give rise to a problem. I have encountered such during many years. But, even this is rare. I had one project where a large distillation column was erected in two sections. The top half got oriented 90 deg. out of position. Go figure that one. What goes wrong is usually something you never imagined. Like an owl's nest in an open pipe. Good luck, and don'[t lose sleep over the work.

 

Bobby

[AZIZ_MN]

Hi Pilesar,

  install GOPRO  camera on the Helmate of last man coming out from the column manhole, or each time after installing one tray manway that person should come out and enter the person who wants to make sure every thing is perfect,but more time consuming, or one more thing, after insalling each tray person should take photograph of important portions of the tray !!?