Coke is cut automatically from drums. [Made by delayed coking]

Conoco Inc. is using an automated system to decoke delayed coker drums at its Humber refinery in the U.K. The company's experience with the system, which is designated the Automated Hydraulic Decoking System, and plans for it are described in this article. Coking is thermal cracking which results in light ends leaving the top of the drum and the heavy ends being deposited in the drum as petroleum coke. This coke can be of many grades. Usually, one of the following three is produced: soft or fuel grade coke, regular grade coke, and premium grade coke. Premium and regular grade cokes are sold to the metals industry for use in electrodes. Fuel grade coke is usually mixed with a low grade solid fuel and then used for fuel. The coke product, which sticks tightly to the sides of the drum, must be removed by hydro-blasting.