Coating for HF Alky Prefrac Charge Drum

What coating should I use in a prefract charge drum in an HF alky unit? Contents include C3's, C4's, anhydrous HF at about 90 F. It is carbon steel and estimated long term corrosion rate is low (2 mpy), 3 mpy on acid outlet. Min/max temperature in the 75 - 115 F range. It is nearing end of life on the shell and I would like to prevent more corrosion if possible.