Hi. We recently performed a OLS in two passes of our DCU furnaces, we were able to reduce skin temperatures below our operational values (1150 F) in an 80% of radiant tubes but we couldn`t do the same with the tubes at convection section. This section is common for the four passes. I guess those tubes don`t “cool” enough to crack the coke formed on their internal surface. Any suggestions? Thanks in advance to your answers.
