I agree with Mr. Mitch, the risks are too high.
In the DCU I worked some years ago, we had a surge tank that was damaged in a fire.
While the tank was being repaired we were able to run the coker without it. Our fractionator had a larger diameter at the bottom, which helped, along with a closer control on the level in the vacuum and fractionator bottoms.)
After the tank was repaired, it was not used again as a surge tank.