Thermal conversion is one of the important areas in distillate and heavy oil processing division. It has two sub area-visbreaking and delayed coking. The main theme of this area is to convert the high contaminant refinery streams to the value-added products. In the late last century, our indigenous visbreaking technology was commercialized at various Indian Refineries. This technology is further updated in recent time and the advanced technology has also been commercialized at three Indian refineries. With the help of EIL, even one of our delayed coker work was commercialized in Numaligarh Refinery Limited. Addition to these, we are now working on the production of needle coke via the delayed coking process.