We are facing problem of shorter run length of our Delayed Coker Unit(DCU). The furnace coil inlet pressure increases to design limit within a very short interval i.e. 30-35 days after the SAD, however the tube skin temp remains well below the design limit.
The feed to the DCU unit is VR from VDU, having asphaltene about 5% & CCR about 17%. The COT, BFW flow and other operating parameters are maintained as per the design operating guidelines.
Can anyone help to identify reasons for the drop in the run length of our DCU?