I worked on a job for CBI building a hydrogen unit out at the Conoco Philips in Wood River Illinois refinery for that tars sands project stuff.  I talked with a guy that said they have the patent for the vertical seam coke drums now or something like that.  This is supposed to be better for the expansion process and allow more volume if i recall correctly.  The horizantal seams didn't expand when the coker gets hot and it looks like you put a bunch of rubber bands around a summer sausage.  So you only get expansion inbetween each of the segments and with the vertical seams it allows for it to swell more evenly allowing you to cram some more goods in there.  Horizantal seam cokers are going to be a thing of the past.  I left before i found out if CBI got the contract for the new cokers they are suppose to put up out there.  Cherne has since moved in and might be doing it now because they have been getting a ton of work out there.  I worked for them on the SZORB (low sulfur absorbtion unit) project for the tar sands stuff in Wood River.

jiweiming,
the Welding Journal issue I'm talking about isn't as recent as I supposed. It's the April, 2004 issue, that contains an article written by Mr. Coby Stewart, who works (or at least worked in those days) for CB&I (again CB&I!). The article explains step by step how to weld vertical coke drums.
By the way, the first time in my life I saw coke drums was as far back as 1969 at the YPF's Lujan de Cuyo refinery in Argentina. The drums were supplied and were being erected by M. W. Kellogg Co. YPF doesn't exist any more, it's been purchased by the Spanish Repsol.
Giovanni S. Crisi